U.S. patent application number 13/204355 was filed with the patent office on 2012-03-15 for color enhancement utilizing up converters and down converters.
This patent application is currently assigned to Immunolight, LLC. Invention is credited to Frederic J. Bourke, JR., Harold Walder.
Application Number | 20120064134 13/204355 |
Document ID | / |
Family ID | 45560088 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120064134 |
Kind Code |
A1 |
Bourke, JR.; Frederic J. ;
et al. |
March 15, 2012 |
COLOR ENHANCEMENT UTILIZING UP CONVERTERS AND DOWN CONVERTERS
Abstract
A light emitting composition including first color emitters and
second color emitters. The first color emitters are configured to
emit, upon exposure to an energy source, visible light at a target
color in response to absorption of energy across a first band of
wavelengths. The second color emitters are configured to emit, upon
exposure to the energy source, visible light at the target color in
response to absorption of energy across a second band of
wavelengths. The light intensity observable at the target color is
enhanced relative to reflected white light without emission from
the first and second color emitters. The light emitting composition
can be a part of a paint, an ink, a fabric, a thread, a road sign,
a highway marking, an automobile, a boat, a plane, a reflector, a
building product, a concrete product, an epoxy product, a jewelry
product, colored contact lens, a candle product, a rubber product,
a plastic product, or other colored surface.
Inventors: |
Bourke, JR.; Frederic J.;
(Greenwich, CT) ; Walder; Harold; (Belville,
NC) |
Assignee: |
Immunolight, LLC
Detroit
MI
|
Family ID: |
45560088 |
Appl. No.: |
13/204355 |
Filed: |
August 5, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61371549 |
Aug 6, 2010 |
|
|
|
Current U.S.
Class: |
424/401 ;
106/287.17; 106/287.18; 106/287.32; 106/287.34; 106/31.13;
252/301.4F; 252/301.4P; 252/301.4R; 252/301.4S; 252/301.6R;
252/301.6S; 252/582; 252/586; 252/588; 313/483; 362/84; 424/59;
424/63; 424/70.1; 424/70.7; 424/70.9; 514/769; 514/770;
977/773 |
Current CPC
Class: |
A61K 8/23 20130101; C09D
11/50 20130101; C09D 5/22 20130101; A61Q 17/04 20130101; G02B 5/23
20130101; C09D 7/66 20180101; A61K 8/20 20130101; A61Q 1/04
20130101; C09D 5/29 20130101; A61K 8/19 20130101; G02B 5/008
20130101; A61K 8/21 20130101; A61K 2800/434 20130101; A61Q 1/02
20130101; A61K 2800/42 20130101; A61K 8/29 20130101; B82Y 30/00
20130101; A61Q 1/10 20130101; A61K 8/24 20130101; A61K 8/25
20130101 |
Class at
Publication: |
424/401 ; 362/84;
313/483; 252/301.4R; 252/586; 252/301.4S; 252/301.4P; 252/301.4F;
252/301.6S; 252/301.6R; 514/769; 514/770; 424/70.7; 424/70.1;
424/63; 424/59; 424/70.9; 252/582; 106/287.18; 106/287.17;
106/287.32; 106/287.34; 106/31.13; 252/588; 977/773 |
International
Class: |
C09K 11/08 20060101
C09K011/08; H01J 1/62 20060101 H01J001/62; G02B 5/23 20060101
G02B005/23; C09K 11/77 20060101 C09K011/77; C09K 11/64 20060101
C09K011/64; C09K 11/62 20060101 C09K011/62; C09K 11/60 20060101
C09K011/60; C09K 11/58 20060101 C09K011/58; C09K 11/87 20060101
C09K011/87; C09K 11/78 20060101 C09K011/78; C09K 11/84 20060101
C09K011/84; C09K 11/85 20060101 C09K011/85; C09K 11/80 20060101
C09K011/80; C09K 11/81 20060101 C09K011/81; C09K 11/82 20060101
C09K011/82; C09K 11/59 20060101 C09K011/59; C09K 11/54 20060101
C09K011/54; C09K 11/88 20060101 C09K011/88; C09K 11/55 20060101
C09K011/55; A61K 8/19 20060101 A61K008/19; A61K 8/02 20060101
A61K008/02; A61K 8/25 20060101 A61K008/25; A61K 8/26 20060101
A61K008/26; A61K 8/29 20060101 A61K008/29; A61K 8/24 20060101
A61K008/24; A61K 8/21 20060101 A61K008/21; A61K 8/20 20060101
A61K008/20; A61K 8/23 20060101 A61K008/23; A61Q 1/10 20060101
A61Q001/10; A61Q 19/00 20060101 A61Q019/00; A61Q 5/00 20060101
A61Q005/00; A61Q 1/08 20060101 A61Q001/08; A61Q 17/04 20060101
A61Q017/04; C09D 1/00 20060101 C09D001/00; C09D 11/00 20060101
C09D011/00; F21V 9/06 20060101 F21V009/06; F21V 9/16 20060101
F21V009/16 |
Claims
1. A light emitting composition comprising: first color emitters
configured to emit, upon exposure to an energy source, visible
light at a first target color in response to absorption of energy
across a first band of wavelengths; second color emitters
configured to emit, upon exposure to the energy source, visible
light at a second target color in response to absorption of energy
across a second band of wavelengths, wherein light intensity
observable at the target color is enhanced relative to reflected
white light without emission from the first and second color
emitters.
2. The composition of claim 1, wherein the first target color and
the second target color are the same.
3. The composition of claim 1, wherein the first target color and
the second target color are different.
4. The composition of claim 1, wherein at least one of the first
and second color emitters comprises light emitting particles having
a diameter less than about 1000 nanometers.
5. The composition of claim 4, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides spectral overlap with either the first or second band of
wavelengths.
6. The composition of claim 4, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the first or second target color.
7. The composition of claim 1, wherein a mixture of the first and
second color emitters are included with dye molecules for a
display.
8. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a color emitting
pixel display element.
9. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a color filter.
10. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a colored surface of
at least one of a paint, an ink, a fabric, a thread, a road sign, a
highway marking, an automobile, a boat, a plane, a reflector, a
building product, a concrete product, an epoxy product, a jewelry
product, colored contact lens, a candle product, a rubber product,
a plastic product, or other colored surface.
11. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a colored reflective
surface.
12. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a colored reflective
surface in a pixel for a display.
13. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a white-light
emitting pixel display element.
14. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component disposed on glass beads
in a retroreflective paint.
15. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a component of a binder layer
securing glass beads in a retroreflective paint to a base
paint.
16. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises an ink component.
17. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from an up conversion process.
18. The composition of claim 1, wherein mixtures of the first and
second color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
an up conversion process.
19. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a down conversion process.
20. The composition of claim 1, wherein mixtures of the first and
second color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
a down conversion process.
21. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a mixture of up converters and down converters.
22. The composition of claim 1, wherein mixtures of the first and
second color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
mixtures of up converters and down converters.
23. The composition of claim 1, wherein a mixture of the first and
second color emitters comprises a mixture of fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof.
24. The composition of claim 1, wherein mixtures of the first and
second color emitters comprise mixtures of fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof.
25. The composition of claim 1, wherein the first and second color
emitters comprise: a first material configured to emit a first
visible color in response to absorption of ultraviolet light; and a
second material configured to emit a second visible color in
response to absorption of infrared light, wherein the second
visible color is different from the first visible color.
26. The composition of claim 25, further comprising a third
material configured to emit a third visible color in response to
absorption of the ultraviolet light, wherein the third visible
color is different from the first visible color and the second
visible color.
27. The composition of claim 25, wherein the first visible color,
the second visible color, and the third visible color are primary
colors.
28. The composition of claim 25, further comprising a third
material configured to emit a third visible color in response to
absorption of the infrared light, wherein the third visible color
is different from the first visible color and the second visible
color.
29. The composition of claim 1, wherein the first and second color
emitters comprises: a first material configured to emit a first
visible color in response to absorption of ultraviolet light; and a
second material configured to emit a second visible color in
response to absorption of infrared light, wherein the second
visible color is substantially the same color as the first visible
color.
30. The composition of claim 29, further comprising a third
material configured to emit a third visible color in response to
absorption of the ultraviolet light, wherein the third visible
color is different from the first visible color and the second
visible color.
31. The composition of claim 29, further comprising a third
material configured to emit a third visible color in response to
absorption of the infrared light, wherein the third visible color
is different from the first visible color and the second visible
color.
32. The composition of claim 29, wherein the first visible color,
the second visible color, and the third visible color are at least
two of the primary colors.
33. The composition of claim 1, wherein at least one of the first
and second color emitters comprises a metallic structure disposed
in relation to a nanoparticle emitter.
34. The composition of claim 33, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
35. The composition of claim 33, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof.
36. The composition of claim 33, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
37. The composition of claim 36, wherein the nanoparticle comprises
a dopant including at least one of Er, Eu, Yb, Tm, Nd, Tb, Ce, Y,
U, Pr, La, Gd and other rare-earth species or a combination
thereof
38. The composition of claim 37, wherein the dopant is included at
a concentration of 0.01%-50% by mol concentration.
39. The composition of claim 1, wherein at least one of the first
and second color emitters comprises a down converter including at
least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn,
Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb MgS; Mn, Yb
CaS; Mn,Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
40. The composition of claim 1, wherein at least one of the first
and second color emitters comprises a dielectric up converter
including at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
41. The composition of claim 40, wherein the dielectric up
converter has a diameter ranging from at least one of 2-1000 nm,
2-100 nm, 2-50 nm, 2-20 nm, or 2-10 nm.
42. The composition of claim 40, wherein: the dielectric up
converter comprises a dopant including at least one of Er, Eu, Yb,
Tm, Nd, Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
43. The composition of claim 40, further comprising a metallic
structure disposed in relation to the dielectric up converter, and
the metallic structure includes at least one of Au, Ag, Cu, Ni, Pt,
Pd, Co, Ru, Rh, Al, Ga, or alloys or layers thereof.
44. The composition of claim 40, wherein the dielectric up
converter is configured to exhibit visible emission upon
interaction with NIR light.
45. The composition of claim 1, wherein at least one of the first
and second color emitters comprise an upconverter including at
least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped-based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
46. A paint comprising: a pigment; and color emitters comprising,
first color emitters configured to emit, upon exposure to an energy
source, visible light at a first target color in response to
absorption of energy across a first band of wavelengths second
color emitters configured to emit, upon exposure to the energy
source, visible light at a second target color in response to
absorption of energy across a second band of wavelengths, wherein
light intensity observable at the first and second target colors is
enhanced relative to reflected white light without emission from
the first and second color emitters.
47. The paint of claim 46, wherein the first target color and the
second target color are the same.
48. The paint of claim 46, wherein the first target color and the
second target color are different.
49. The paint of claim 46, wherein at least one of the first and
second color emitters comprise light emitting particles having a
diameter less than about 1000 nanometers.
50. The paint of claim 49, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides spectral overlap with either the first or second band of
wavelengths.
51. The paint of claim 49, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the first or second target color.
52. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises a component of a colored surface of
at least one of a paint, a fabric, a thread, a road sign, a highway
marking, an automobile, a boat, a plane, and a reflector, or other
painted surface.
53. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises a component disposed on glass beads
in a retroreflective paint.
54. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises a component of a binder layer
securing glass beads in a retroreflective paint to a base
paint.
55. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from an up conversion process.
56. The paint of claim 46, wherein mixtures of the first and second
color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
an up conversion process.
57. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a down conversion process.
58. The paint of claim 46, wherein mixtures of the first and second
color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
a down conversion process.
59. The paint of claim 46, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a mixture of up converters and down converters.
60. The paint of claim 46, wherein mixtures of the first and second
color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
mixtures of up converters and down converters.
61. The paint of claim 46, wherein a mixture of the color emitters
comprises a mixture of fluorescent emitters including at least one
of europium, terbium, cerium, and erbium or combinations
thereof.
62. The paint of claim 46, wherein mixtures of the color emitters
comprise mixtures of fluorescent emitters including at least one of
europium, terbium, cerium, and erbium or combinations thereof.
63. The paint of claim 46, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is different from the first visible color.
64. The paint of claim 63, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
65. The paint of claim 64, wherein the first visible color, the
second visible color, and the third visible color are primary
colors.
66. The paint of claim 63, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
67. The paint of claim 46, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is substantially the same color as the first
visible color.
68. The paint of claim 67, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
69. The paint of claim 67, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
70. The paint of claim 69, wherein the first visible color, the
second visible color, and the third visible color are at least two
of the primary colors.
71. The paint of claim 46, wherein at least one of the first or
second color emitters comprises a metallic structure disposed in
relation to a nanoparticle emitter.
72. The paint of claim 71, wherein the metallic structure comprises
a metallic shell having at least one of a spherical shell, an
oblate shell, a crescent shell, a multilayer shell, a star-shaped
shell, a cone-shaped shell, or a rod-shaped shell.
73. The paint of claim 71, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof.
74. The paint of claim 71, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
75. The paint of claim 74, wherein the nanoparticle comprises a
dopant including at least one of Er, Eu, Yb, Tm, Nd, Tb, Ce, Y, U,
Pr, La, Gd and other rare-earth species or a combination
thereof.
76. The paint of claim 75, wherein the dopant is included at a
concentration of 0.01%-50% by mol concentration.
77. The paint of claim 46, wherein at least one of the first and
second color emitters comprises a down converter including at least
one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn, Er
MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb MgS; Mn, Yb CaS;
Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
78. The paint of claim 77, wherein at least one of the first and
second color emitters comprises a dielectric up converter including
at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4,
NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3,
La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4, YbF.sub.3,
YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or layers
thereof.
79. The paint of claim 78, wherein the dielectric up converter has
a diameter ranging from at least one of 2-1000 nm, 2-100 nm, 2-50
nm, 2-20 nm, or 2-10 nm.
80. The paint of claim 78, wherein: the dielectric up converter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof and the dopant has a concentration of 0.01%-50%
by mol concentration.
81. The paint of claim 78, further comprising a metallic structure
disposed in relation to the dielectric up converter, and the
metallic structure includes at least one of Au, Ag, Cu, Ni, Pt, Pd,
Co, Ru, Rh, Al, Ga, or alloys or layers thereof.
82. The paint of claim 66, wherein the dielectric up converter is
configured to exhibit visible emission upon interaction with NIR
light.
83. The paint of claim 46, wherein at least one of the first and
second color emitters comprise an upconverter including at least
one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped-based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
84. An ink comprising: a dye; and color emitters included in the
dye, and comprising, first color emitters configured to emit, upon
exposure to an energy source, visible light at a first target color
in response to absorption of energy across a first band of
wavelengths, second color emitters configured to emit, upon
exposure to the energy source, visible light at a second target
color in response to absorption of energy across a second band of
wavelengths, wherein light intensity observable at the first and
second target colors is enhanced relative to reflected white light
without emission from the first and second color emitters.
85. The ink of claim 84, wherein the first target color and the
second target color are the same.
86. The ink of claim 84, wherein the first target color and the
second target color are different.
87. The ink of claim 84, wherein at least one of the first and
second color emitters comprises light emitting particles having a
diameter less than about 1000 nanometers.
88. The ink of claim 87, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides spectral overlap with either the first or second band of
wavelengths.
89. The ink of claim 87, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the first or second target color.
90. The ink of claim 84, wherein a mixture of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from an up conversion
process.
91. The ink of claim 84, wherein mixtures of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from an up conversion
process.
92. The ink of claim 84, wherein a mixture of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a down conversion
process.
93. The ink of claim 84, wherein mixtures of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a down conversion
process.
94. The ink of claim 84, wherein a mixture of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a mixture of up
converters and down converters.
95. The ink of claim 84, wherein mixtures of color emitters
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from mixtures of up
converters and down converters.
96. The ink of claim 84, wherein at least one of the first or
second color emitters comprises a mixture of fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof.
97. The ink of claim 84, wherein mixtures of the first and second
color emitters comprise mixtures of fluorescent emitters including
at least one of europium, terbium, cerium, and erbium or
combinations thereof.
98. The ink of claim 84, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is different from the first visible color.
99. The ink of claim 98, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
100. The ink of claim 99, wherein the first visible color, the
second visible color, and the third visible color are primary
colors.
101. The ink of claim 98, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
102. The ink of claim 84, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is substantially the same color as the first
visible color.
103. The ink of claim 102, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
104. The ink of claim 102, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
105. The ink of claim 104, wherein the first visible color, the
second visible color, and the third visible color are at least two
of the primary colors.
106. The ink of claim 84, wherein at least one of the first and
second color emitters comprises a metallic structure disposed in
relation to a nanoparticle emitter.
107. The ink of claim 106, wherein the metallic structure comprises
a metallic shell having at least one of a spherical shell, an
oblate shell, a crescent shell, a multilayer shell, a star-shaped
shell, a cone-shaped shell, or a rod-shaped shell.
108. The ink of claim 106, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof.
109. The ink of claim 106, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
110. The ink of claim 109, wherein the nanoparticle emitter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof.
111. The ink of claim 110, wherein the dopant is included at a
concentration of 0.01%-50% by mol concentration.
112. The ink of claim 84, wherein at least one of the first and
second color emitters comprises a down converter including at least
one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn, Er
MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn,Yb MgS; Mn, Yb CaS;
Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
113. The ink of claim 84, wherein at least one of the first and
second color emitters comprises a dielectric up converter including
at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4,
NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3,
La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4, YbF.sub.3,
YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or layers
thereof.
114. The ink of claim 113, wherein the dielectric up converter has
a diameter ranging from at least one of 2-1000 nm, 2-100 nm, 2-50
nm, 2-20 nm, or 2-10 nm.
115. The ink of claim 113, wherein: the dielectric up converter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
116. The ink of claim 113, further comprising a metallic structure
disposed in relation to the dielectric up converter, and the
metallic structure includes at least one of Au, Ag, Cu, Ni, Pt, Pd,
Co, Ru, Rh, Al, Ga, or alloys or layers thereof.
117. The ink of claim 113, wherein the dielectric up converter is
configured to exhibit visible emission upon interaction with NIR
light.
118. The ink of claim 84, wherein the dye comprises a dye for an
electronic display device.
119. The ink of claim 84, wherein the dye comprises a printing
dye.
120. The ink of claim 84, wherein at least one of the first and
second color emitters comprise an upconverter including at least
one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped -based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R=Li, Na, K) glasses, and metal-to-ligand charge transfer (MLCT)
transition materials, and MLCT transition materials including
[Ru(dmb).sub.3].sup.2+ (dmb=4,4'-dimethyl-2,2'-bipyridine).
121. A light display comprising: at least one of a color filter or
a color reflective surface; color emitters included in the color
filter or the color reflective surface, and including, first color
emitters configured to emit, upon exposure to a light source,
visible light at a target color in response to absorption of energy
across a first band of wavelengths, and second color emitters
configured to emit, upon exposure to the light source, visible
light at the target color in response to absorption of energy
across a second band of wavelengths, wherein light intensity
observable at the target color is enhanced relative to reflected
white light without emission from the first and second color
emitters.
122. The display of claim 121, wherein the first target color and
the second target color are the same.
123. The display of claim 121, wherein the first target color and
the second target color are different.
124. The display of claim 121, wherein at least one of the first
and second color emitters comprises light emitting particles having
a diameter less than about 1000 nanometers.
125. The display of claim 124, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the target color.
126. The display of claim 124, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from an up conversion process.
127. The display of claim 121, wherein a mixture of the first and
second color emitters is attached to dye molecule in a pixel of the
display.
128. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color emitting
pixel element of the display.
129. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color filter of
the display.
130. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color filter for a
display of the display.
131. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color surface of
the display.
132. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color reflective
surface of the display.
133. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a color reflective
surface in a pixel of the display.
134. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a component of a white-light
emitting pixel display element of the display.
135. The display of claim 121, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from an up conversion process.
136. The display of claim 121, wherein mixtures of the first and
second color emitters comprise at least one of red, blue, and green
emitters configured to produce red, blue, and green emissions from
an up conversion process.
137. The display of claim 121, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a down conversion process.
138. The display of claim 121, wherein mixtures of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a down conversion process.
139. The display of claim 121, wherein a mixture of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from a mixture of up converters and down converters.
140. The display of claim 121, wherein mixtures of the first and
second color emitters comprises at least one of red, blue, and
green emitters configured to produce red, blue, and green emissions
from mixtures of up converters and down converters.
141. The display of claim 121, wherein a mixture of the first and
second color emitters comprises a mixture of fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof.
142. The display of claim 121, wherein mixtures of the first and
second color emitters comprise mixtures of fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof.
143. The display of claim 121, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is different from the first visible color.
144. The display of claim 143, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
145. The display of claim 144, wherein the first visible color, the
second visible color, and the third visible color are primary
colors.
146. The display of claim 144, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
147. The display of claim 121, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is substantially the same color as the first
visible color.
148. The display of claim 145, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
149. The display of claim 145, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
150. The display of claim 149, wherein the first visible color, the
second visible color, and the third visible color are at least two
of the primary colors.
151. The display of claim 121, wherein at least one of the first
and second color emitters comprises a metallic structure disposed
in relation to a nanoparticle emitter.
152. The display of claim 151, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
153. The display of claim 151, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof
154. The display of claim 151, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
155. The display of claim 154, wherein the nanoparticle comprises a
dopant including at least one of Er, Eu, Yb, Tm, Nd, Tb, Ce, Y, U,
Pr, La, Gd and other rare-earth species or a combination
thereof
156. The display of claim 155, wherein the dopant is included at a
concentration of 0.01%-50% by mol concentration.
157. The display of claim 121, wherein at least one of the first
and second color emitters comprises a down converter including at
least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn,
Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb MgS; Mn, Yb
CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
158. The display of claim 121, wherein at least one of the first
and second color emitters comprises a dielectric up converter
including at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
159. The display of claim 158, wherein the dielectric up converter
has a diameter ranging from at least one of 2-1000 nm, 2-100 nm,
2-50 nm, 2-20 nm, or 2-10 nm.
160. The display of claim 158, wherein: the dielectric up converter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
161. The display of claim 158, further comprising a metallic
structure disposed in relation to the dielectric up converter, and
the metallic structure includes at least one of Au, Ag, Cu, Ni, Pt,
Pd, Co, Ru, Rh, Al, Ga, or alloys or layers thereof.
162. The display of claim 158, wherein the dielectric up converter
is configured to exhibit visible emission upon interaction with NIR
light.
163. The display of claim 121, wherein at least one of the first
and second color emitters comprise an upconverter including at
least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped -based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
164. A protective coating for moderating UV light damage to an
object exposed to UV light irradiation, comprising: a mixture of
light scattering and light emitting particles configured, upon
exposure to UV light, to convert a first part of the UV light into
visible light, emit from the mixture a fraction of the visible
light, and reflect from the mixture a second part of the UV light
such that said second part of the UV light is not absorbed by said
object.
165. The coating of claim 164, wherein said light scattering and
light emitting particles have a diameter less than about 1000
nanometers.
166. The coating of claim 164, wherein the particles comprise a
particle having a metallic structure disposed in relation to the
particle, wherein a physical characteristic of the metallic
structure is set to a value where a surface plasmon resonance in
the metallic structure resonates at a frequency which provides
spectral overlap with the UV light.
167. The coating of claim 164, wherein the particles comprise a
particle having a metallic structure disposed in relation to the
particle, wherein a physical characteristic of the metallic
structure is set to a value where a surface plasmon resonance in
the metallic structure resonates at a frequency which provides
enhanced emission at a color having an energy lower than the UV
light.
168. The coating of claim 164, wherein the mixture of particles
comprises a component of a color filter.
169. The coating of claim 164, wherein the mixture of particles
comprises a component of a color filter for a picture.
170. The coating of claim 164, wherein the mixture of particles
comprises a component of a colored surface of at least one of a
paint, an ink, a fabric, a thread, a road sign, a highway marking,
an automobile, a boat, a plane, a reflector, a building product, a
concrete product, an epoxy product, a jewelry product, colored
contact lens, a candle product, a rubber product, a plastic
product, or other colored surface.
171. The coating of claim 164, wherein the mixture of particles
comprises a component of a colored reflective surface.
172. The coating of claim 164, wherein the mixture of particles
comprises a paint component.
173. The coating of claim 164, wherein the mixture of particles
comprises a component disposed on glass beads in a retroreflective
paint.
174. The coating of claim 164, wherein the mixture of particles
comprises a component of a binder layer securing glass beads in a
retroreflective paint to a base paint.
175. The coating of claim 164, wherein the mixture of particles
comprises an ink component.
176. The coating of claim 164, wherein the mixture of particles
comprises at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a down conversion
process.
177. The coating of claim 164, wherein mixtures of the light
scattering and light emitting particles comprise at least one of
red, blue, and green emitters configured to produce red, blue, and
green emissions from a down conversion process.
178. The coating of claim 164, wherein the mixture of particles
comprise fluorescent emitter including at least one of europium,
terbium, cerium, and erbium or combinations thereof.
179. The coating of claim 164, wherein mixtures of the light
scattering and light emitting particles comprise fluorescent
emitters including at least one of europium, terbium, cerium, and
erbium or combinations thereof.
180. The coating of claim 164, wherein the particles comprises a
metallic structure disposed in relation to a nanoparticle
emitter.
181. The coating of claim 180, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
182. The coating of claim 180, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof
183. The coating of claim 164, wherein the particles comprise a
down converter including at least one of Y.sub.2O.sub.3; ZnS; ZnSe;
MgS; CaS; Mn, Er ZnSe; Mn, Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb
ZnSe; Mn, Yb MgS; Mn, Yb CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+;
ZnS:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+,
Er3.sup.+; ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
184. A light emitting composition comprising: first color emitters
configured to emit, upon exposure to an energy source at an energy
higher than or lower than the visible light spectrum, visible light
at a first target color; second color emitters configured to emit,
upon exposure to the energy source, visible light at a second
target color, wherein light intensity observable at the first and
second target colors is enhanced relative to reflected white light
without emission from the first and second color emitters.
185. The composition of claim 184, wherein the first target color
and the second target color are the same.
186. The composition of claim 184, wherein the first target color
and the second target color are different.
187. The composition of claim 184, wherein the first color emitters
are configured to emit upon exposure to at least one of ultraviolet
light, x-rays, and high energy particles.
188. The composition of claim 184, wherein the first color emitters
are configured to emit upon exposure to at least one of near
infrared, infrared, and microwave irradiation.
189. The composition of claim 184, wherein at least one of the
first and second color emitters comprises light emitting particles
having a diameter less than about 1000 nanometers.
190. The composition of claim 189, wherein the light emitting
particles comprise a particle having a metallic structure disposed
in relation to the particle, wherein a physical characteristic of
the metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides spectral overlap with either the energy of the energy
source.
191. The composition of claim 189, wherein the light emitting
particles comprise a particle having a metallic structure disposed
in relation to the particle, wherein a physical characteristic of
the metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the first or second target color.
192. The composition of claim 184, wherein a mixture of the first
and second color emitters comprises a component of a colored
surface of at least one of a paint, an ink, a fabric, a thread, a
road sign, a highway marking, an automobile, a boat, a plane, a
reflector, a building product, a concrete product, an epoxy
product, a jewelry product, colored contact lens, a candle product,
a rubber product, a plastic product, or other colored surface.
193. The composition of claim 184, wherein a mixture of the first
and second color emitters comprises a component of a white-light
emitting pixel display element.
194. The composition of claim 184, wherein a mixture of the first
and second color emitters comprises a mixture of fluorescent
emitters including at least one of europium, terbium, cerium, and
erbium or combinations thereof.
195. The composition of claim 184, wherein at least one of the
first and second color emitters comprises a down converter
including at least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn,
Er ZnSe; Mn, Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb
MgS; Mn, Yb CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
196. The composition of claim 184, wherein at least one of the
first and second color emitters comprises an up converter including
at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4,
NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3,
La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4, YbF.sub.3,
YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or layers
thereof.
197. The composition of claim 184, wherein at least one of the
first and second color emitters comprise an upconverter including
at least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped -based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
198. A light emitting composition comprising: first color emitters
configured to emit, upon exposure to an energy source, visible
light at a first target color in response to absorption of energy
at a first band of wavelengths; second color emitters configured to
emit, upon exposure to the energy source, visible light at a second
target color offset from said first target color in response to
absorption of energy at the first band of wavelengths, wherein
light intensity observable at the first and second target colors is
enhanced relative to reflected white light without emission from
the first and second color emitters.
199. The composition of claim 198, wherein the offset comprises an
offset of 10 nm in the wavelength of the target color to change the
chromaticity of the target color.
200. The composition of claim 198, wherein the offset comprises an
offset of 20 nm in the wavelength of the target color to change the
chromaticity of the target color.
201. The composition of claim 198, wherein the offset comprises an
offset of 30 nm in the wavelength of the target color to change the
chromaticity of the target color.
202. The composition of claim 198, wherein the offset comprises an
offset of 100 nm in the wavelength of the target color to change
the saturation of the target color.
203. The composition of claim 198, wherein the offset comprises an
offset of 200 nm in the wavelength of the target color to change
the saturation of the target color.
204. The composition of claim 198, wherein the offset comprises an
offset of 300 nm in the wavelength of the target color to change
the saturation of the target color.
205. A cosmetic product comprising: color emitters including, first
color emitters configured to emit, upon exposure to an energy
source, visible light at a first target color in response to
absorption of energy across a first band of wavelengths second
color emitters configured to emit, upon exposure to the energy
source, visible light at a second target color in response to
absorption of energy across a second band of wavelengths, wherein
light intensity observable at the first and second target colors is
enhanced relative to reflected white light without emission from
the first and second color emitters.
206. The product of claim 205, wherein the first target color and
the second target color are the same.
207. The product of claim 205, wherein the first target color and
the second target color are different.
208. The product of claim 205, wherein at least one of the first
and second color emitters comprise light emitting particles having
a diameter less than about 1000 nanometers.
209. The product of claim 208, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides spectral overlap with either the first or second band of
wavelengths.
210. The product of claim 208, wherein the light emitting particles
comprise a particle having a metallic structure disposed in
relation to the particle, wherein a physical characteristic of the
metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the first or second target color.
211. The product of claim 205, wherein the color emitters comprise
a component disposed on glass beads in a retroreflective
cosmetic.
212. The product of claim 205, wherein the color emitters comprise
a component of a base layer securing glass beads in a
retroreflective cosmetic.
213. The product of claim 205, wherein the color emitters comprise
at least one of red, blue, and green emitters configured to produce
red, blue, and green emissions from an up conversion process.
214. The product of claim 205, wherein mixtures of the color
emitters comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from an up
conversion process.
215. The product of claim 205, wherein the color emitters comprise
at least one of red, blue, and green emitters configured to produce
red, blue, and green emissions from a down conversion process.
216. The product of claim 205, wherein mixtures of the color
emitters comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from a down
conversion process.
217. The product of claim 205, wherein the color emitters comprise
at least one of red, blue, and green emitters configured to produce
red, blue, and green emissions from a mixture of up converters and
down converters.
218. The product of claim 205, wherein mixtures of the color
emitters comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from mixtures
of up converters and down converters.
219. The product of claim 205, wherein the color emitters comprise
at least one fluorescent emitter including at least one of
europium, terbium, cerium, and erbium or combinations thereof.
220. The product of claim 205, wherein mixtures of the color
emitters comprise fluorescent emitters including at least one of
europium, terbium, cerium, and erbium or combinations thereof.
221. The product of claim 205, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is different from the first visible color.
222. The product of claim 221, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
223. The product of claim 222, wherein the first visible color, the
second visible color, and the third visible color are primary
colors.
224. The product of claim 221, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
225. The product of claim 205, wherein at least one of the first or
second color emitters comprises: a first material configured to
emit a first visible color in response to absorption of ultraviolet
light; and a second material configured to emit a second visible
color in response to absorption of infrared light, wherein the
second visible color is substantially the same color as the first
visible color.
226. The product of claim 225, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
227. The product of claim 225, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
228. The product of claim 227, wherein the first visible color, the
second visible color, and the third visible color are at least two
of the primary colors.
229. The product of claim 205, wherein color emitters comprises a
metallic structure disposed in relation to a nanoparticle
emitter.
230. The product of claim 229, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
231. The product of claim 229, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof.
232. The product of claim 229, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
233. The product of claim 232, wherein the nanoparticle emitter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof.
234. The product of claim 233, wherein the dopant is included at a
concentration of 0.01%-50% by mol concentration.
235. The product of claim 205, wherein at least one of the first
and second color emitters comprises a down converter including at
least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn,
Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb MgS; Mn, Yb
CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er.sup.3+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
236. The product of claim 205, wherein at least one of the first
and second color emitters comprises a dielectric up converter
including at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
237. The product of claim 236, wherein the dielectric up converter
has a diameter ranging from at least one of 2-1000 nm, 2-100 nm,
2-50 nm, 2-20 nm, or 2-10 nm.
238. The product of claim 236, wherein: the dielectric up converter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
239. The product of claim 236, further comprising a metallic
structure disposed in relation to the dielectric up converter, and
the metallic structure includes at least one of Au, Ag, Cu, Ni, Pt,
Pd, Co, Ru, Rh, Al, Ga, or alloys or layers thereof.
240. The product of claim 236, wherein the dielectric up converter
is configured to exhibit visible emission upon interaction with NIR
light.
241. The product of claim 205, wherein at least one of the first
and second color emitters comprise an upconverter including at
least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped -based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
242. The product of claim 205, further comprising: a skin cream
having the color emitters.
243. The product of claim 205, further comprising: a mascara having
the color emitters.
244. The product of claim 205, further comprising: at least one of
a shampoo, hair conditioner, hair gel, hair styling compound, hair
spray, and hair cream having the color emitters.
245. The product of claim 205, further comprising: a lip balm
having the color emitters.
246. The product of claim 205, further comprising: a blush having
the color emitters.
247. A cosmetic product for moderating UV light damage to skin
exposed to UV light irradiation, comprising: a mixture of light
scattering and light emitting particles configured, upon exposure
to UV light, to convert a first part of the UV light into visible
light, emit from the mixture a fraction of the visible light, and
reflect from the mixture a second part of the UV light such that
said second part of the UV light is not absorbed by said skin.
248. A cosmetic product for moderating UV light damage to hair
exposed to UV light irradiation, comprising: a mixture of light
scattering and light emitting particles configured, upon exposure
to UV light, to convert a first part of the UV light into visible
light, emit from the mixture a fraction of the visible light, and
reflect from the mixture a second part of the UV light such that
said second part of the UV light is not absorbed by said hair.
249. A light emitting composition comprising: color emitters
configured to emit, upon exposure to an energy source, visible
light at a target color in response to absorption of said energy at
a first wavelength .lamda..sub.1; wherein the color emitters are at
least one of up converters or down converters producing the target
color which is enhanced relative to reflected white light without
emission from the color emitter, the color emitters comprise light
emitting particles having a metallic structure disposed in relation
to the particle, and a physical characteristic of the metallic
structure is set to a value where a surface plasmon resonance in
the metallic structure resonates at a frequency which provides
spectral overlap with the first wavelength .lamda..sub.1.
250. The composition of claim 249, wherein the light emitting
particles having a diameter less than about 1000 nanometers.
251. The composition of claim 249, wherein the color emitters
produce the target color from a band of energy about the first
wavelength .lamda..sub.1.
252. The composition of claim 249, wherein the physical
characteristic of the metallic structure is set to a value where a
surface plasmon resonance in the metallic structure resonates at a
frequency which provides enhanced emission at the target color.
253. The composition of claim 249, wherein the particles are
included with dye molecules for a display.
254. The composition of claim 249, wherein the particles comprise a
component of a color emitting pixel display element.
255. The composition of claim 249, wherein the particles comprise a
component of a color filter.
256. The composition of claim 249, wherein the particles comprise a
component of a color filter for a display.
257. The composition of claim 249, wherein the particles comprise a
component of a colored surface of at least one of a paint, an ink,
a fabric, a thread, a road sign, a highway marking, an automobile,
a boat, a plane, a reflector, a building product, a concrete
product, an epoxy product, a jewelry product, colored contact lens,
a candle product, a rubber product, a plastic product, or other
colored surface.
258. The composition of claim 249, wherein the particles comprise a
component of a colored reflective surface.
259. The composition of claim 249, wherein the particles comprise a
component of a colored reflective surface in a pixel for a
display.
260. The composition of claim 249, wherein the particles comprise a
component of a white-light emitting pixel display element.
261. The composition of claim 249, wherein the particles comprise a
paint component.
262. The composition of claim 249, wherein the particles comprise a
component disposed on glass beads in a retroreflective paint.
263. The composition of claim 249, wherein the particles comprise a
component of a binder layer securing glass beads in a
retroreflective paint to a base paint.
264. The composition of claim 249, wherein the particles comprise
comprises an ink component.
265. The composition of claim 249, wherein a mixture of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from an up
conversion process.
266. The composition of claim 249, wherein mixtures of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from an up
conversion process.
267. The composition of claim 249, wherein a mixture of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from a down
conversion process.
268. The composition of claim 249, wherein mixtures of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from a down
conversion process.
269. The composition of claim 249, wherein a mixture of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from a mixture
of up converters and down converters.
270. The composition of claim 249, wherein mixtures of the
particles comprise at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from mixtures
of up converters and down converters.
271. The composition of claim 249, wherein a mixture of the
particles comprises a mixture of fluorescent emitters including at
least one of europium, terbium, cerium, and erbium or combinations
thereof.
272. The composition of claim 249, wherein mixtures of the
particles comprises mixtures of fluorescent emitters including at
least one of europium, terbium, cerium, and erbium or combinations
thereof.
273. The composition of claim 249, wherein the particles comprise:
a first material configured to emit a first visible color in
response to absorption of ultraviolet light; and a second material
configured to emit a second visible color in response to absorption
of infrared light, wherein the second visible color is different
from the first visible color.
274. The composition of claim 273, further comprising a third
material configured to emit a third visible color in response to
absorption of the ultraviolet light, wherein the third visible
color is different from the first visible color and the second
visible color.
275. The composition of claim 274, wherein the first visible color,
the second visible color, and the third visible color are primary
colors.
276. The composition of claim 273, further comprising a third
material configured to emit a third visible color in response to
absorption of the infrared light, wherein the third visible color
is different from the first visible color and the second visible
color.
277. The composition of claim 249, wherein the particles comprise:
a first material configured to emit a first visible color in
response to absorption of ultraviolet light; and a second material
configured to emit a second visible color in response to absorption
of infrared light, wherein the second visible color is
substantially the same color as the first visible color.
278. The composition of claim 277, further comprising a third
material configured to emit a third visible color in response to
absorption of the ultraviolet light, wherein the third visible
color is different from the first visible color and the second
visible color.
279. The composition of claim 277, further comprising a third
material configured to emit a third visible color in response to
absorption of the infrared light, wherein the third visible color
is different from the first visible color and the second visible
color.
280. The composition of claim 279, wherein the first visible color,
the second visible color, and the third visible color are at least
two of the primary colors.
281. The composition of claim 249, wherein the metallic structure
is disposed in relation to a nanoparticle emitter.
282. The composition of claim 281, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
283. The composition of claim 282, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof
284. The composition of claim 281, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
285. The composition of claim 284, wherein the nanoparticle
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof
286. The composition of claim 285, wherein the dopant is included
at a concentration of 0.01%-50% by mol concentration.
287. The composition of claim 249, wherein said down converter
comprises at least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn,
Er ZnSe; Mn, Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb
MgS; Mn, Yb CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er3.sup.+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
288. The composition of claim 249, wherein said up converter
comprises a dielectric up converter including at least one of
Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4, NaYbF.sub.4, YAG, YAP,
Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2,
LuPO.sub.4, YVO.sub.4, YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or
SiO.sub.2 or alloys or layers thereof.
289. The composition of claim 288, wherein the dielectric up
converter has a diameter ranging from at least one of 2-1000 nm,
2-100 nm, 2-50 nm, 2-20 nm, or 2-10 nm.
290. The composition of claim 288, wherein: the dielectric up
converter comprises a dopant including at least one of Er, Eu, Yb,
Tm, Nd, Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
291. The composition of claim 288, wherein the metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or alloys or layers thereof.
292. The composition of claim 288, wherein the dielectric up
converter is configured to exhibit visible emission upon
interaction with NIR light.
293. The composition of claim 288, wherein the upconverter
comprises at least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NsGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped -based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine).
294. A cosmetic product comprising: color emitters configured to
emit, upon exposure to an energy source, visible light at a target
color in response to absorption of said energy at a first
wavelength .lamda..sub.1; wherein the color emitters are at least
one of up converters or down converters producing the target color
which is enhanced relative to reflected white light without
emission from the color emitter, the color emitters comprise light
emitting particles having a metallic structure disposed in relation
to the particle, and a physical characteristic of the metallic
structure is set to a value where a surface plasmon resonance in
the metallic structure resonates at a frequency which provides
spectral overlap with the first wavelength .lamda..sub.1.
295. The product of claim 294, wherein the light emitting particles
having a diameter less than about 1000 nanometers.
296. The product of claim 294, wherein the color emitters produce
the target color from a band of energy about the first wavelength
.lamda..sub.1.
297. The product of claim 294, wherein the physical characteristic
of the metallic structure is set to a value where a surface plasmon
resonance in the metallic structure resonates at a frequency which
provides enhanced emission at the target color.
298. The product of claim 294, wherein the color emitters comprise
a component disposed on glass beads in a retroreflective
cosmetic.
299. The product of claim 289, wherein the color emitters comprise
a component of a base layer securing glass beads in a
retroreflective cosmetic.
300. The product of claim 294, wherein a mixture of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from an up conversion
process.
301. The product of claim 294, wherein mixtures of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from an up conversion
process.
302. The product of claim 294, wherein a mixture of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a down conversion
process.
303. The product of claim 294, wherein mixtures of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a down conversion
process.
304. The product of claim 294, wherein a mixture of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from a mixture of up
converters and down converters.
305. The product of claim 294, wherein mixtures of the particles
comprise at least one of red, blue, and green emitters configured
to produce red, blue, and green emissions from mixtures of up
converters and down converters.
306. The product of claim 294, wherein a mixture of the particles
comprises a mixture of fluorescent emitters including at least one
of europium, terbium, cerium, and erbium or combinations
thereof.
307. The product of claim 294, wherein mixtures of the particles
comprises mixtures of fluorescent emitters including at least one
of europium, terbium, cerium, and erbium or combinations
thereof.
308. The product of claim 294, wherein the particles comprise: a
first material configured to emit a first visible color in response
to absorption of ultraviolet light; and a second material
configured to emit a second visible color in response to absorption
of infrared light, wherein the second visible color is different
from the first visible color.
309. The product of claim 308, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
310. The product of claim 309, wherein the first visible color, the
second visible color, and the third visible color are primary
colors.
311. The product of claim 308, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
312. The product of claim 294, wherein the particles comprise: a
first material configured to emit a first visible color in response
to absorption of ultraviolet light; and a second material
configured to emit a second visible color in response to absorption
of infrared light, wherein the second visible color is
substantially the same color as the first visible color.
313. The product of claim 312, further comprising a third material
configured to emit a third visible color in response to absorption
of the ultraviolet light, wherein the third visible color is
different from the first visible color and the second visible
color.
314. The product of claim 312, further comprising a third material
configured to emit a third visible color in response to absorption
of the infrared light, wherein the third visible color is different
from the first visible color and the second visible color.
315. The product of claim 314, wherein the first visible color, the
second visible color, and the third visible color are at least two
of the primary colors.
316. The product of claim 294, wherein the metallic structure is
disposed in relation to a nanoparticle emitter.
317. The product of claim 316, wherein the metallic structure
comprises a metallic shell having at least one of a spherical
shell, an oblate shell, a crescent shell, a multilayer shell, a
star-shaped shell, a cone-shaped shell, or a rod-shaped shell.
318. The product of claim 316, wherein said metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or a combination or alloys or layers thereof.
319. The product of claim 316, wherein the nanoparticle emitter
comprises at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2 or alloys or
layers thereof.
320. The product of claim 319, wherein the nanoparticle comprises a
dopant including at least one of Er, Eu, Yb, Tm, Nd, Tb, Ce, Y, U,
Pr, La, Gd and other rare-earth species or a combination
thereof.
321. The product of claim 320, wherein the dopant is included at a
concentration of 0.01%-50% by mol concentration.
322. The product of claim 294, wherein said down converter
comprises at least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn,
Er ZnSe; Mn, Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn, Yb ZnSe; Mn, Yb
MgS; Mn, Yb CaS; Mn, Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er3.sup.+;
ZnS:Mn.sup.2+; ZnS:Mn, Er.sup.3+.
323. The product of claim 294, wherein said up converter comprises
a dielectric up converter including at least one of Y.sub.2O.sub.3,
Y.sub.2O.sub.2S, NaYF.sub.4, NaYbF.sub.4, YAG, YAP,
Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2,
LuPO.sub.4, YVO.sub.4, YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or
SiO.sub.2 or alloys or layers thereof.
324. The product of claim 323, wherein the dielectric up converter
has a diameter ranging from at least one of 2-1000 nm, 2-100 nm,
2-50 nm, 2-20 nm, or 2-10 nm.
325. The product of claim 323, wherein: the dielectric up converter
comprises a dopant including at least one of Er, Eu, Yb, Tm, Nd,
Tb, Ce, Y, U, Pr, La, Gd and other rare-earth species or a
combination thereof; and the dopant has a concentration of
0.01%-50% by mol concentration.
326. The product of claim 323, wherein the metallic structure
comprises at least one of Au, Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al,
Ga, or alloys or layers thereof.
327. The product of claim 323, wherein the dielectric up converter
is configured to exhibit visible emission upon interaction with NIR
light.
328. The product of claim 294, wherein the upconverter comprises at
least one of Tm.sup.3+ doped flourozirconate glasses,
LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and YbPO.sub.4:Er.sup.3+
nanocrystals, tellurium and germanium oxides, tellurium and
germanium oxides doped with at least one Tm, Yb, Ho, Er, or Pr,
Yb.sup.3+ doped BaZrO.sub.3, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6,
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6, Nd.sup.3+ and Ho.sup.3+
co-doped-based ZrF.sub.4 fluoride glasses,
Tm.sup.3+/Yb.sup.3+-codoped TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O
(R.dbd.Li, Na, K) glasses, and metal-to-ligand charge transfer
(MLCT) transition materials, and MLCT transition materials
including [Ru(dmb).sub.3].sup.2+
(dmb.dbd.4,4'-dimethyl-2,2'-bipyridine).
329. A method for enhancing visible light emission from a surface,
comprising: providing on the surface a mixture of color emitters,
said mixture including first color emitters configured to emit,
upon exposure to an energy source, visible light at a first target
color in response to absorption of energy across a first band of
wavelengths and including second color emitters configured to emit,
upon exposure to the energy source, visible light at a second
target color in response to absorption of energy across a second
band of wavelengths, wherein light intensity observable at the
first and second target colors is enhanced relative to reflected
white light without emission from the first and second color
emitters; exposing the first and second color emitters to an energy
source; and emitting said visible light at at least one of the
first and second target colors by conversion of a part of said
energy into said visible light.
330. The method of claim 329, wherein the emitting said visible
light comprises emitting the same first and second target
color.
331. The method of claim 329, wherein the emitting said visible
light comprises emitting different first and second target
colors.
332. The method of claim 329, wherein the providing comprises
providing the mixture of color emitters on at least one of a paint,
an ink, a fabric, a thread, a road sign, a highway marking, an
automobile, a boat, a plane, a reflector, a building product, a
concrete product, an epoxy product, a jewelry product, colored
contact lens, a candle product, a rubber product, a plastic
product, or other colored surface.
333. A method for enhancing visible light emission from a paint,
comprising: providing in the paint or in a vicinity of a surface of
the paint a mixture of color emitters, said mixture including first
color emitters configured to emit, upon exposure to an energy
source, visible light at a first target color in response to
absorption of energy across a first band of wavelengths and
including second color emitters configured to emit, upon exposure
to the energy source, visible light at a second target color in
response to absorption of energy across a second band of
wavelengths, wherein light intensity observable at the first and
second target colors is enhanced relative to reflected white light
without emission from the first and second color emitters; exposing
the first and second color emitters to an energy source; and
emitting said visible light at at least one of the first and second
target colors by conversion of a part of said energy into said
visible light.
334. The method of claim 333, wherein the emitting said visible
light comprises emitting the same first and second target
color.
335. The method of claim 333, wherein the emitting said visible
light comprises emitting different first and second target
colors.
336. A method for enhancing visible light emission from an ink,
comprising: providing in the ink a mixture of color emitters, said
mixture including first color emitters configured to emit, upon
exposure to an energy source, visible light at a first target color
in response to absorption of energy across a first band of
wavelengths and including second color emitters configured to emit,
upon exposure to the energy source, visible light at a second
target color in response to absorption of energy across a second
band of wavelengths, wherein light intensity observable at the
first and second target colors is enhanced relative to reflected
white light without emission from the first and second color
emitters; exposing the first and second color emitters to an energy
source; and emitting said visible light at at least one of the
first and second target colors by conversion of a part of said
energy into said visible light.
337. The method of claim 336, wherein the emitting said visible
light comprises emitting the same first and second target
color.
338. The method of claim 336, wherein the emitting said visible
light comprises emitting different first and second target
colors.
339. A method for enhancing visible light emission from a display,
comprising: providing on a color filter or a color reflective
surface of the display a mixture of color emitters, said mixture
including first color emitters configured to emit, upon exposure to
an energy source, visible light at a first target color in response
to absorption of energy across a first band of wavelengths and
including second color emitters configured to emit, upon exposure
to the energy source, visible light at a second target color in
response to absorption of energy across a second band of
wavelengths, wherein light intensity observable at the first and
second target colors is enhanced relative to reflected white light
without emission from the first and second color emitters; exposing
the first and second color emitters to an energy source; and
emitting said visible light at at least one of the first and second
target colors by conversion of a part of said energy into said
visible light.
340. The method of claim 339, wherein the emitting said visible
light comprises emitting the same first and second target
color.
341. The method of claim 339, wherein the emitting said visible
light comprises emitting different first and second target colors.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to and claims priority under 35
U.S.C. .sctn.119(e) to U.S. provisional patent application
61/371,549, filed Aug. 6, 2010. This application is related to U.S.
provisional patent application 61/161,328, filed Mar. 18, 2009 and
to U.S. provisional patent application 61/259,940, filed Nov. 10,
2009, the entire disclosures of which are hereby incorporated by
reference. This application is related to U.S. Ser. No. 12/725,108,
the entire disclosures of which are hereby incorporated by
reference.
[0002] This application is related to Provisional Applications Ser.
No. 60/954,263, filed Aug. 6, 2007, and 61/030,437, filed Feb. 21,
2008, and U.S. application Ser. No. 12/059,484, filed Mar. 31,
2008, the contents of which are hereby incorporated herein by
reference. This application is also related to U.S. application
Ser. No. 11/935,655, filed Nov. 6, 2007; and Provisional
Applications Ser. No. 61/042,561, filed April 4, 2008; 61/035,559,
filed Mar. 11, 2008, and 61/080,140, filed Jul. 11, 2008, the
entire contents of which are hereby incorporated herein by
reference. This application is related to U.S. patent application
Ser. No. 12/401,478 filed Mar. 10, 2009, the entire contents of
which are hereby incorporated herein by reference. This application
is related to U.S. patent application Ser. No. 11/935,655, filed
Nov. 6, 2007, and Ser. No. 12/059,484, filed Mar. 31, 2008; U.S.
patent application Ser. No. 12/389,946, filed Feb. 20, 2009; U.S.
patent application Ser. No. 12/417,779, filed Apr. 3, 2009, the
entire disclosures of which are hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The invention relates to methods and systems for generating
or enhancing light emission or reflectance from visible displays
and colored surfaces so as to enhance the appearance of the visible
object.
[0005] 2. Discussion of the Background
[0006] Presently, light (i.e., electromagnetic radiation from the
radio frequency through the visible to the X-ray wavelength range)
is used in a number of industrial, communication, electronic, and
pharmaceutical processes. Light in the infrared and visible range
is typically generated from an electrical energy source which for
example either heats a material to extremely high temperatures
where black body emission occurs (as in an incandescent lamp).
Light in the visible and ultraviolet range is typically generated
by heating a gas to an electrical discharge where transitions from
one electronic state of the gas atom or molecule occur with the
emission of light. There are also semiconductor based light sources
(as in light emitting diodes and semiconducting lasers) where
electrons/holes in a material recombine to produce light
emission.
[0007] Visible light is defined as the electromagnetic radiation
with wavelengths between 380 nm and 750 nm. In general,
electromagnetic radiation including light is generated by the
acceleration and deceleration or changes in movement (vibration) of
electrically charged particles, such as parts of molecules (or
adjacent atoms) with high thermal energy, or electrons in atoms (or
molecules).
[0008] For reference purposes, infra-red (IR) radiation just beyond
the red end of the visible region; and, ultra-violet (UV) radiation
has a shorter wavelength than violet light. The UV portion of the
spectrum is divided into three regions: UVA (315-400 nm), UVB
(280-315 nm) and UVC (100-280 nm).
[0009] Industrial lamps used in lighting applications cover the
visible range of wavelengths for proper white perception. Thermal
sources like heated filaments can be made of different type
conductors, including W-filaments, halogen-protected W-filaments,
and electrically induced high temperature plasmas (arc lamps).
[0010] The power (energy emitted per second) of a radiant source is
frequently expressed in watts (W), but light can also be expressed
in lumens (lm) to account for the varying sensitivity of the eye to
different wavelengths of light. The derived relevant units are the
radiance (luminance) of a source in W/m.sup.2 (lm/m.sup.2) in a
certain direction per steradian (unit of solid angle) and the
irradiance (illuminance) of a surface in W/m.sup.2 (lm/m.sup.2 or
lux).
[0011] With the development of ultraviolet sources, ultraviolet
radiation is being increasingly utilized for industrial, chemical,
and pharmaceutical purposes. For example, UV light is known to
sterilize media and is known to drive a number of photo-activated
chemical processes such as the cross-linking of polymers in
adhesives or coatings. Typically, ultraviolet sources use gas
discharge lamps to generate emitted light in the ultraviolet range.
The emitted light is then optically filtered to remove many of not
all of the non-ultraviolet frequencies. Ultraviolet light can also
be produced in semiconductor phosphors from the excitation of these
phosphors from high energy sources such as, for example, X-ray
irradiation.
[0012] With the development of infrared radiation sources, infrared
radiation is being increasingly utilized for communications and
signaling purposes. Typically, infrared sources use broad spectrum
light sources referred to as glowbars to generate a broad spectrum
of light centered in the infrared range or use lasers to emit very
specific infrared wavelengths. For the broad band sources, the
emitted light is optically filtered to remove many, if not all, of
the non-infrared frequencies.
[0013] It is generally desirable to have devices, materials, and
capabilities to convert light from one frequency range to another.
Down conversion has been one way to convert higher energy light to
lower energy, as used in the phosphors noted above. Up conversion
has also been shown where lower energy light is converted to higher
energy light. Typically, this process is a multi-photon absorption
process where two or more photons are used to promote an excited
electronic state in a host medium which in turn radiates at a
wavelength of light that has a higher energy than the energy of the
incident light which promoted the multi-photon absorption process.
Both down conversion and up conversion have been studied and
documented in the past.
[0014] Indeed, workers have studied the phenomenon of
photoluminescence and fluorescence, which is the ability of certain
solids to emit light when driven or charged by an external energy
source. Many well-known phosphors and fluorescors are triggered by
high-energy electrons or photons and emit photons of lower energy.
It has been recognized that certain infrared phosphors can convert
infrared light to light in the visible range (violet through
red).
[0015] The properties of light such as its radiance is particularly
important in reading or display applications where the human eye
has to perceive and discern temporary images or permanent images
(as for example shown by road and highway signs) formed with
visible light. Televisions, computer monitors, displays, and signs
use a cathode ray technololyg (CRT) technology where high energy
electrons impinge on phosphors that emit visible light.
Televisions, computer monitors, displays, and signs more recently
have used liquid crystal display or plasma display technology to
generate visible images discernable to the human eye.
[0016] In these and other reading or display applications, attempts
have been made to develop displays with relatively high contrast
images while minimizing the amount of broadband light emitted or
reflected from a display, which may detract from the contrast of
the image displayed.
SUMMARY OF THE INVENTION
[0017] In one embodiment, there is provided a light emitting
composition including first color emitters configured to emit, upon
exposure to an energy source, visible light at a target color in
response to absorption of energy across a first band of wavelengths
and including second color emitters configured to emit, upon
exposure to the energy source, visible light at the target color in
response to absorption of energy across a second band of
wavelengths. The light intensity observable at the target color is
enhanced relative to reflected white light without emission from
the first and second color emitters.
[0018] In another embodiment, there is provided a paint including a
pigment and a mixture of color-emitters included in the pigment.
The mixture includes first color emitters configured to emit, upon
exposure to an energy source, visible light at a target color in
response to absorption of energy across a first band of wavelengths
and including second color emitters configured to emit, upon
exposure to the energy source, visible light at the target color in
response to absorption of energy across a second band of
wavelengths. The light intensity observable at the target color is
enhanced relative to reflected white light without emission from
the first and second color emitters. In another embodiment, there
is provided an ink including a dye and a mixture of color-emitters
included in the dye. The mixture includes first color emitters
configured to emit, upon exposure to an energy source, visible
light at a target color in response to absorption of energy across
a first band of wavelengths and including second color emitters
configured to emit, upon exposure to the energy source, visible
light at the target color in response to absorption of energy
across a second band of wavelengths. The light intensity observable
at the target color is enhanced relative to reflected white light
without emission from the first and second color emitters.
[0019] In another embodiment, there is provided a display including
a color filter or a color reflective surface and a mixture of
color-emitters included in the color filter or the color reflective
surface. The mixture includes first color emitters configured to
emit, upon exposure to an energy source, visible light at a target
color in response to absorption of energy across a first band of
wavelengths and including second color emitters configured to emit,
upon exposure to the energy source, visible light at the target
color in response to absorption of energy across a second band of
wavelengths. The light intensity observable at the target color is
enhanced relative to reflected white light without emission from
the first and second color emitters.
[0020] In another embodiment, there is provided a method for
enhancing visible light emission from a surface. The method
provides on the surface a mixture of color emitters including first
color emitters configured to emit, upon exposure to an energy
source, visible light at a target color in response to absorption
of energy across a first band of wavelengths and including second
color emitters configured to emit, upon exposure to the energy
source, visible light at the target color in response to absorption
of energy across a second band of wavelengths. The light intensity
observable at the target color is enhanced relative to reflected
white light without emission from the first and second color
emitters. The method exposes the color emitters to an energy
source. The method emits the visible light at a first wavelength
.lamda..sub.1 by conversion of a part of the energy into the
visible light at the first wavelength .lamda..sub.1.
[0021] In another embodiment, there is provided a method for
enhancing visible light emission from a paint. The method provides
in the paint or in a vicinity of a surface of the paint a mixture
of color emitters including first color emitters configured to
emit, upon exposure to an energy source, visible light at a target
color in response to absorption of energy across a first band of
wavelengths and including second color emitters configured to emit,
upon exposure to the energy source, visible light at the target
color in response to absorption of energy across a second band of
wavelengths. The light intensity observable at the target color is
enhanced relative to reflected white light without emission from
the first and second color emitters. The method exposes the color
emitters to an energy source. The method emits the visible light at
a first wavelength .lamda..sub.1 by conversion of a part of the
energy into the visible light at the first wavelength
.lamda..sub.1.
[0022] In another embodiment, there is provided a method for
enhancing visible light emission from an ink. The method provides
in the ink a mixture of color emitters including first color
emitters configured to emit, upon exposure to an energy source,
visible light at a target color in response to absorption of energy
across a first band of wavelengths and including second color
emitters configured to emit, upon exposure to the energy source,
visible light at the target color in response to absorption of
energy across a second band of wavelengths. The light intensity
observable at the target color is enhanced relative to reflected
white light without emission from the first and second color
emitters. The method exposes the color emitters to an energy
source. The method emits the visible light at a first wavelength
.lamda..sub.1 by conversion of a part of the energy into the
visible light at the first wavelength .lamda..sub.1.
[0023] In another embodiment, there is provided a method for
enhancing visible light emission from a display. The method
provides on a color filter or a color reflective surface of the
display a mixture of color emitters including first color emitters
configured to emit, upon exposure to an energy source, visible
light at a target color in response to absorption of energy across
a first band of wavelengths and including second color emitters
configured to emit, upon exposure to the energy source, visible
light at the target color in response to absorption of energy
across a second band of wavelengths. The light intensity observable
at the target color is enhanced relative to reflected white light
without emission from the first and second color emitters. The
method exposes the color emitters to an energy source. The method
emits the visible light at a first wavelength .lamda..sub.1 by
conversion of a part of the energy into the visible light at the
first wavelength .lamda..sub.1.
[0024] It is to be understood that both the foregoing general
description of the invention and the following detailed description
are exemplary, but are not restrictive of the invention.
BRIEF DESCRIPTION OF THE FIGURES
[0025] A more complete appreciation of the invention and many of
the attendant advantages thereof will be readily obtained as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0026] FIG. 1 is an energy diagram of an infrared phosphor
system;
[0027] FIG. 2 is a schematic energy level diagram showing
upconversion excitation and visible emissions schemes for
Er.sup.3+, Tm.sup.3+ and or Yb.sup.3+ ions;
[0028] FIG. 3 is an energy diagram showing energy states for a
four-photon upconversion process in Y.sub.2O.sub.3
nanocrystals;
[0029] FIG. 4A is a schematic illustration of various upconverter
structures of the invention;
[0030] FIG. 5 is a schematic illustration of plasmon resonance as a
function of shell thickness;
[0031] FIG. 6A is a schematic illustration of other various
upconverter structures of the invention;
[0032] FIG. 6B is another schematic illustration of other various
upconverter structures of the invention;
[0033] FIG. 6C is a schematic illustration of plasmonics-active
upconverter structures of the invention;
[0034] FIG. 6D is a schematic illustration of photo-active
molecules linked to plasmonics-active upconverter structures of the
invention;
[0035] FIG. 7 is a schematic representation of the retro-reflective
paint geometry using the color shifting particles of this
invention;
[0036] FIG. 8 is a schematic representation of a top coat on a
painted surface which includes the color shifting particles of this
invention;
[0037] FIGS. 9A-9D are schematic representations of an electronic
ink display using the color shifting particles of this
invention;
[0038] FIGS. 10A-10C are schematic representations of IR light
activated displays using the color shifting particles of this
invention; and
[0039] FIG. 11 is a schematic representation of of a LCD light
activated display in which the color filters have the color
shifting particles of this invention.
DETAILED DESCRIPTION OF THE INVENTION
[0040] This invention is directed to methods and systems for
producing electromagnetic radiation having desirable frequency
windows (at least one frequency within a desirable frequency range)
from other electromagnetic radiation having lower or higher
frequency ranges using up converting transitional media or down
converting transitional media as the case may apply.
[0041] In various embodiments of the invention, there are provided
systems and methods for up conversion of light e.g., from the IR
regime into visible electromagnetic radiation and for down
conversion of light e.g., from the UV range into visible
electromagnetic radiation. The invention in various embodiments up
converts energy, preferably light in the visible spectrum and/or
downLets also include other areas of the electromagnetic spectrum,
from radio to gamma converts energy, preferably light in the
visible spectrum. The invention encompasses a variety of
applications where the up and down conversions are conducted to
enhance the color of the object being displayed. These application
areas can include paints on signs, walls, cars, buildings, boats,
airplanes. These application areas can include display monitors,
computer monitors, telephone displays, watch dials, instrument
dials to name but a few.
[0042] Among various materials, luminescent nanoparticles have
attracted increasing technological and industrial interest. In the
context of the invention, nanoparticle refers to a particle having
a size less than one micron. While the description of the invention
describes specific examples using nanoparticles, the invention in
many embodiments is not limited to particles having a size less
than one micron. However, in many of the embodiments, the size
range of less than one micron, and especially less than 100 nm
produces properties of special interest such as for example
emission lifetime luminescence quenching, luminescent quantum
efficiency, and concentration quenching and such as for example
diffusion, penetration, and dispersion into mediums where larger
size particles would not migrate.
[0043] The invention in various embodiments can use a wide variety
of down conversion materials (or mixtures of down converters) to
enhance a particular color of light observable from reflective
material or surface. These down conversion materials can include
quantum dots, semiconductor materials, alloys of semiconductor
materials, scintillation and phosphor materials, materials that
exhibit X-ray excited luminescence (XEOL), organic solids, metal
complexes, inorganic solids, crystals, rare earth materials
(lanthanides), polymers, scintillators, phosphor materials, etc.,
and materials that exhibit excitonic properties. Accordingly, the
down conversion materials to enhance color emission can convert
energy from one of ultraviolet light, x-rays, and high energy
particles to visible light. The down conversion materials to
enhance color emission can convert energy from higher energy
visible light to lower energy visible light.
[0044] In one embodiment of the invention, a quantum dot mixture
can be used for the multiple nanoparticles. Quantum dots are in
general nanometer size particles whose energy states in the
material of the quantum dot are dependent on the size of the
quantum dot. For example, quantum dots are known to be
semiconductors whose conducting characteristics are closely related
to the size and shape of the individual crystal. Generally, the
smaller the size of the crystal, the larger the band gap, the
greater the difference in energy between the highest valence band
and the lowest conduction band becomes. Therefore, more energy is
needed to excite the dot, and concurrently, more energy is released
when the crystal returns to its resting state. In fluorescent dye
applications, this equates to higher frequencies of light emitted
after excitation of the dot as the crystal size grows smaller,
resulting in a color shift from red to blue in the light emitted.
Quantum dots represent one way to down convert ultraviolet light of
the spectrum to a targeted color emission, such as for example a
green light emission. Quantum dots represent one way to down
convert blue light of the spectrum to a targeted color emission,
such as for example a green light emission.
[0045] Specifically, in one embodiment of the invention, a quantum
dot mixture (QDM) coating can be deposited using CVD and or sol-gel
techniques using standard precipitation techniques. The QDM coating
can be made of a silicate structure that does not diminish UV
output. Within the silicate family, silica (SiO.sub.2) is suitable
since it maximizes UV transmission through the coating. The coating
can further include a second layer of a biocompatible glass. Such
bio-compatible glass and glass ceramic compositions can contain
calcium, a lanthanide or yttrium, silicon, phosphorus and oxygen.
Other biocompatible materials and techniques are described in the
following patents which are incorporated herein in their entirety:
U.S. Pat. Nos. 5,034,353; 4,786,617; 3,981,736; 3,922,155;
4,120,730; and U.S. Pat. Appl. Nos. 2008/0057096; 2006/0275368; and
2010/0023101.
[0046] Further, the down conversion materials for the invention
described here can be coated with insulator materials such as for
example silica which will reduce the likelihood of any chemical
interaction between the luminescent particles and the medium the
particles are included therein. For biocompatible applications of
inorganic nanoparticles, one of the major limiting factors is their
toxicity. Generally speaking, all semiconductor nanoparticles are
more or less toxic. For biocompatible applications, nanoparticles
with toxicity as low as possible are desirable or else the
nanoparticles have to remain separated from the medium. Pure
TiO.sub.2, ZnO, and Fe.sub.2O.sub.3 are biocompatible. CdTe and
CdSe are toxic, while ZnS, CaS, BaS, SrS and Y.sub.2O.sub.3 are
less toxic. In addition, the toxicity of nanoparticles can result
from their inorganic stabilizers, such as TGA, or from dopants such
as Eu.sup.2+, Cr.sup.3+ or Nd.sup.3+. Other suitable down
conversion materials which would seem the most biocompatible are
zinc sulfide, ZnS:Mn.sup.2+, ferric oxide, titanium oxide, zinc
oxide, zinc oxide containing small amounts of Al.sub.2O.sub.3 and
AgI nanoclusters encapsulated in zeolite. For non-medical
applications, where toxicity may not be as critical a concern, the
following materials (as well as those listed elsewhere) are
considered suitable: lanthanum and gadolinium oxyhalides activated
with thulium; Er.sup.3+ doped BaTiO.sub.3 nanoparticles, Yb.sup.3+
doped CsMnCl.sub.3 and RbMnCl.sub.3, BaFBr:Eu.sup.2+ nanoparticles,
Cesium Iodine, Bismuth Germanate, Cadmium Tungstate, and CsBr doped
with divalent Eu.
[0047] In various embodiments of the invention, the following
luminescent polymers are also suitable as conversion materials:
poly(phenylene ethynylene), poly(phenylene vinylene),
poly(p-phenylene), poly(thiophene), poly(pyridyl vinylene),
poly(pyrrole), poly(acetylene), poly(vinyl carbazole),
poly(fluorenes), and the like, as well as copolymers and/or
derivatives thereof.
[0048] In various embodiments of the invention, the following
particles can be used similar to that detailed in U.S. Pat. No.
7,090,355, the entire contents of which are incorporated herein by
reference. For down-conversion, the following materials can be
used. Inorganic or ceramic phosphors or nano-particles, including
but not limited to metal oxides, metal halides, metal chalcoginides
(e.g. metal sulfides), or their hybrids, such as metal oxo-halides,
metal oxo-chalcoginides. Laser dyes and small organic molecules,
and fluorescent organic polymers. Semiconductor nano-particles,
such as II-VI or III-V compound semiconductors, e.g. fluorescent
quantum dots. Organometallic molecules including at least a metal
center such as rare earth elements (e.g. Eu, Tb, Ce, Er, Tm, Pr,
Ho) and transitional metal elements such as Cr, Mn, Zn, Ir, Ru, V,
and main group elements such as B, Al, Ga, etc. The metal elements
are chemically bonded to organic groups to prevent the quenching of
the fluorescence from the hosts or solvents. Phosphors can be used
including the Garnet series of phosphors:
(Y.sub.mA.sub.1-m).sub.3(Al.sub.nB.sub.1-n).sub.5O.sub.12, doped
with Ce; where 0.ltoreq.m, n.ltoreq.1, where A includes other rare
earth elements, B includes B, Ga. In addition, phosphors containing
metal silicates, metal borates, metal phosphates, and metal
aluminates hosts can be used. In addition, nano-particulates
phosphors containing common rare earth elements (e.g. Eu, Tb, Ce,
Dy, Er, Pr, Tm) and transitional or main group elements (e.g. Mn,
Cr, Ti, Ag, Cu, Zn, Bi, Pb, Sn, TI) as the fluorescent activators,
can be used. Materials such as Ca, Zn, Cd in tungstates, metal
vanadates, ZnO, etc. can be used.
[0049] The commercial laser dyes obtained from several laser dye
vendors, including Lambda Physik, and Exciton, etc can be used. A
partial list of the preferred laser dye classes includes:
Pyrromethene, Coumarin, Rhodamine, Fluorescein, other aromatic
hydrocarbons and their derivatives, etc . In addition, there are
many polymers containing unsaturated carbon-carbon bonds, which
also serve as fluorescent materials and find many optical and
fluorescent applications. For example, MEH-PPV, PPV, etc have been
used in opto-electronic devices, such as polymer light emitting
diodes (PLED). Such fluorescent polymers can be used directly as
the fluorescent layer of the transparent 2-D display screen.
[0050] As noted above, semiconductor nanoparticles (e.g., quantum
dots) can be used. The terms "semiconductor nanoparticles," in the
art refers to an inorganic crystallite between 1 nm and 1000 nm in
diameter, preferably between 2 nm to 50 nm. A semiconductor
nano-particle is capable of emitting electromagnetic radiation upon
excitation (i.e., the semiconductor nano-particle is luminescent).
The nanoparticle can be either a homogeneous nano-crystal, or
comprises of multiple shells. For example, the nanoparticle can
include a "core" of one or more first semiconductor materials, and
may be surrounded by a "shell" of a second semiconductor material.
The core and/or the shell can be a semiconductor material
including, but not limited to, those of the group II-VI (ZnS, ZnSe,
ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, MgS, MgSe, MgTe, CaS, CaSe,
CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, and the like) and III-V
(GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, and the like) and IV
(Ge, Si, and the like) materials, and an alloy or a mixture
thereof.
[0051] Fluorescent organometallic molecules containing rare earth
or transitional element cations can be used for down conversion.
Such molecules include a metal center of rare earth elements
including Eu, Tb, Er, Tm, Ce protected with organic chelating
groups. The metal center may also include transitional elements
such as Zn, Mn, Cr, Ir, etc and main group elements such as B, Al,
Ga. Such organometallic molecules can readily dissolved in liquid
or transparent solid host media. Some examples of such fluorescent
organomettalic molecules include: 1.
Tris(dibenzoylmethane)mono(phenanthroline)europium(III); 2.
Tris(8-hydroxyquinoline)erbium; 3.
Tris(1-phenyl-3-methyl-4-(2,2-dimethylpropan-1-oyl)pyrazolin-5-one)terbiu-
m(III); 4. Bis(2-methyl-8-hydroxyquinolato)zinc; 5.
Diphenylborane-8-hydroxyquinolate.
[0052] Specific examples of down-converting particles for red
emission include those discussed above and europium complexes such
as those described in JP Laid-open Patent Publication (Kokai) No.
2003-26969, constructed such that .beta.-diketone ligand is
coordinated to europium forming an europium complex capable of
emitting red fluorescence. Other specific examples of the rare
earth element complexes include complexes include lanthanum (Ln),
europium (Eu), terbium (Tb), and gadolinium (Gd) and combinations
thereof. An europium (Eu) complex is capable of emitting red
fluorescence when irradiated with ultraviolet rays having a
wavelength ranging from 365 nm to 410 nm. Terbium (Tb) is capable
of emitting green fluorescence when irradiated with ultraviolet
rays having a wavelength of 365 nm.
[0053] In other down-conversion embodiments, light emitting
particles which emit red light may include europium, light emitting
particles which emit green light may include Terbium, and light
emitting particles which emit blue or yellow light may include
cerium (and/or thulium). In up-conversion embodiments, light
emitting particles which emit red light may include praseodymium,
light emitting particles which emit green light may include erbium,
and light emitting particles which emit blue light may include
thulium. In embodiments, light emitting particles can be
fluorescent molecules that emit different colors (e.g. red, green,
and blue). In embodiments, light emitting particles can be included
in pure organic or organo-metallic dyes.
[0054] In addition to the combinations of rare earth complexes,
such as a combination of a europium complex and a terbium complex,
it is also possible employ a combination of a europium complex and
a green-emitting fluorescent substance which is not a complex, or a
combination of a terbium complex and a red-emitting fluorescent
substance which is not a complex.
[0055] Other down converters include for example ZnS, PbS,
SbS.sub.3, MoS.sub.2, PbTe, PbSe, BeO, MgO. Li.sub.2CO.sub.3,
Ca(OH).sub.2, MoO.sub.3, SiO.sub.2, Al.sub.2O.sub.3, TeO.sub.2,
SnO.sub.2, KBr, KCl, and NaCl. These materials can include dopants
to tailor the emission properties, as noted above. Examples of
doped (or alloyed) glass systems suitable for the include
Y.sub.2O.sub.3:Gd, Y.sub.2O.sub.3:Dy, Y.sub.2O.sub.3:Tb,
Y.sub.2O.sub.3:Ho, Y.sub.2O.sub.3:Er, Y.sub.2O.sub.3:Tm,
Gd.sub.2O.sub.3:Eu, Y.sub.2O.sub.2S:Pr, Y.sub.2O.sub.2S:Sm,
Y.sub.2O.sub.2S:Eu, Y.sub.2O.sub.2S:Tb, Y.sub.2O.sub.2S:Ho,
Y.sub.2O.sub.2S:Er, Y.sub.2O.sub.2S:Dy, Y.sub.2O.sub.2S:Tm,
ZnS:Ag:Cl (blue), ZnS:Cu:Al (green), Y.sub.2O.sub.2S:Eu (red),
Y.sub.2O.sub.3:Eu (red), YVO.sub.4:Eu (red), and Zn.sub.2SiO.sub.4
Mn (green).
[0056] Alternatively, quantum dots (as described above) can be used
to tailor the down conversion process. As described in U.S. Pat.
No. 6,744,960 (the entire contents of which are incorporated by
reference), different size quantum dots produce different color
emissions. In that work and applicable to this invention, quantum
dots can comprise various materials including semiconductors such
as zinc selenide (ZnSe), cadmium selenide (CdSe), cadmium sulfide
(CdS), indium arsenide (InAs), and indium phosphide (InP). Another
material that may suitably be employed is titanium dioxide
(TiO.sub.2). The size of the particle, i.e., the quantum dot 18,
may range from about 2 to 10 nm. Since the size of these particles
is so small, quantum physics governs many of the electrical and
optical properties of the quantum dot. One such result of the
application of quantum mechanics to the quantum dot 18 is that
quantum dots absorb a broad spectrum of optical wavelengths and
re-emit radiation having a wavelength that is longer than the
wavelength of the absorbed light. The wavelength of the emitted
light is governed by the size of the quantum dot. For example, CdSe
quantum dots 5.0 nm in diameter emit radiation having a narrow
spectral distribution centered about 625 nm while quantum dots 18
including CdSe 2.2 nm in size emit light having a center wavelength
of about 500 nm. Semiconductor quantum dots comprising CdSe, InP,
and InAs, can emit radiation having center wavelengths in the range
between 400 nm to about 1.5 .mu.m. Titanium dioxide TiO.sub.2 also
emits in this range. The linewidth of the emission, i.e.,
full-width half-maximum (FWHM), for these semiconductor materials
may range from about 20 to 30 nm. To produce this narrowband
emission, quantum dots simply need to absorb light having
wavelengths shorter than the wavelength of the light emitted by the
dots. For example, for 5.0 nm diameter CdSe quantum dots light
having wavelengths shorter than about 625 nm is absorbed to produce
emission at about 625 nm while for 2.2 nm quantum dots comprising
CdSe light having wavelengths smaller than about 500 nm is absorbed
and re-emitted at about 500 nm. In practice, however, the
excitation or pump radiation is at least about 50 nanometers
shorter than the emitted radiation.
[0057] With regard more specifically to down converters suitable
for the invention, U.S. Pat. No. 4,705,952 (the contents of which
are hereby incorporated herein by reference) describes an
infrared-triggered phosphor that stores energy in the form of
visible light of a first wavelength and released energy in the form
of visible light of a second wavelength when triggered by infrared
light. The phosphors in U.S. Pat. No. 4,705,952 were compositions
of alkaline earth metal sulfides, rare earth dopants, and fusible
salts. The phosphors in U.S. Pat. No. 4,705,952 were more
specifically phosphors made from strontium sulfide, barium sulfide
and mixtures thereof; including a dopant from the rare earth series
and europium oxide, and mixtures thereof; and including a fusible
salt of fluorides, chlorides, bromides, and iodides of lithium,
sodium, potassium, cesium, magnesium, calcium, strontium, and
barium, and mixtures thereof. The materials described in U.S. Pat.
No. 4,705,952 are useful in various embodiments of the
invention.
[0058] In other embodiments of the invention, the down converters
(or mixtures of down converters) can include Y.sub.2O.sub.3: Li.
Sun et al "Luminescent properties of Li+ doped nanosized
Y.sub.2O.sub.3:Eu," Solid State Comm. 119 (2001) 393-396 (the
entire contents of which are incorporated herein by reference)
describe such materials. Hou et al "Luminescent properties
nano-sized Y.sub.2O.sub.3:Eu fabricated by co-precipitation
method," Journal of Alloys and Compounds, vol. 494, issue 1-2, 2
Apr. 2010, pages 382-385 (the entire contents of which are
incorporated herein by reference) describe that nano-sized yttria
(Y.sub.2O.sub.3) powders have been successfully synthesized by a
co-precipitation method. The powders were well crystallized, and
the grains were almost spherical with good dispersibility. The
quenching concentration of Eu.sup.3+ ions is 9 mol % which is much
higher than micro-scaled powders. The incorporation of Li+ ions
greatly improved the luminescence intensity. The highest emission
intensity was observed with 4 mol % Li+ doped Y.sub.2O.sub.3:Eu
powder ((Y.sub.0.87Eu.sub.0.09Li.sub.0.04).sub.2O.sub.3) and the
fluorescence intensity was increased by as much as 79%. Yi et al
"Improved cathodoluminescent characteristics of
Y.sub.2O.sub.3:Eu.sup.3+ thin films by Li-doping," Appl. Phys. A
87, 667-671 (2007) (the entire contents of which are incorporated
herein by reference) describe cathodoluminescent spectra for both
Y.sub.2O.sub.3:Eu.sup.3+ and Li-doped Y.sub.2O.sub.3:Eu.sup.3+
films and methods for making these materials.
[0059] These references show that Li-doped Y.sub.2O.sub.3 materials
can be used as down converters or in the mixtures of down
converters and therefore would be acceptable materials for the
color enhancing mixtures of the invention. This material is an
especially suited material for x-ray stimulated emissions in the
ultraviolet to violet region of the light spectrum.
[0060] The invention in other embodiments use a wide variety of up
conversion materials (or mixtures of up converters) to enhance a
particular color of light observable from reflective material or
surface. These up conversion materials can include similar
materials as discussed above with regard to down conversion but
typically included doped or impurity states in a host crystal that
provide a mechanism for up conversion pumping. Accordingly, the up
conversion materials to enhance color emission can convert energy
from one of near infrared, infrared, and microwave irradiation. The
upconversion materials to enhance color emission can convert energy
from lower energy visible light to higher energy visible light.
[0061] Reference will now be made in detail to a number of
embodiments of the invention, examples of which are illustrated in
the accompanying drawings, in which like reference characters refer
to corresponding elements.
[0062] The energy relations present in the upconverter in U.S. Pat.
No. 4,705,952 are shown in the energy diagram of FIG. 1, where
energy states E and T are introduced by two selected impurities.
Excitation of these states by absorption of light or energy having
a minimum energy of E minus G will cause electrons to be raised to
the band at energy state E. When charging illumination ceases, many
of the excited electrons will fall to energy state T and remain
trapped there. The trapping phenomenon is illustrated at the left
of FIG. 1. Later exposure to triggering illumination of infrared
light can supply E minus T energies, permitting the
infrared-triggered phosphor in excited state T to transition to
level E, as shown at the right of FIG. 1. A photon is emitted
during this transition process. The resulting light emission is
characterized by a wavelength associated with E minus G.
[0063] If the depth of the trap is several times higher than the
thermal energy, more than 99% of the electrons are in the
electron-hole trap. If the depth of the traps is about 1 eV, then
in the dark, most of the traps are filled, band E is almost empty
and electron hole recombination is negligible. Here the choice of
appropriate phosphors presents an occurrence where the charging
light (of an energy higher than visible light) stores itself to be
emitted upon exposure to infrared light (of an energy lower than
visible light) to thereby emit visible light.
[0064] Considerable effort has gone into the synthesis of
luminescent nanoparticles, and numerous investigations of their
optical properties have been performed. The synthesis of oxide
nanoparticles such as those that are based on lanthanides have been
achieved by a number of processes including solid-gel (sol-gel)
techniques, gas phase condensation or colloidal chemical methods.
While efforts to make concentrated colloidal solutions of highly
uniform size luminescent nanoparticles have met with some technical
difficulties, synthesis of useful amounts of some 5 nanometer sized
lanthanide doped oxides have been achieved as shown in a paper by
Bazzi et al entitled Synthesis and luminescent properties of sub
5-nm lanthanide oxide particles, in the Journal of Luminescence 102
(2003) pages 445-450, the entire contents of which are incorporated
herein by reference. The work by Bazzi et al concentrated on
understanding the properties on lanthanide oxide nanonparticles
with an emphasis on the microstructural properties and optical
emission properties (i.e. concentrated on the fluorescence and down
conversion properties of these materials). Nevertheless, the
materials described by Bazzi et al are useful in various
embodiments of the invention.
[0065] The present inventors have realized that such upconversion
materials can be used in various ways to enhance visible light
emission by way of conversion of infrared light from a solar
spectrum (as in daylight exposure) or a black body spectrum (as in
an incandescent lamp). In one example to be described below, a
nanoparticle of a lanthanide doped oxide can be excited with near
infrared laser light such as 980 nm and 808 nm to produce visible
light in different parts of the red, green, blue spectrum depending
on the dopant trivalent rare earth ion(s) chosen, their
concentration, and the host lattice.
[0066] Other work reported by Suyver et al in Upconversion
spectroscopy and properties of NaYF.sub.4 doped with Er.sup.3+,
Tm.sup.3+ and or Yb.sup.3+, in Journal of Luminescence 117 (2006)
pages 1-12, the entire contents of which are incorporated herein by
reference, recognizes in the NaYF.sub.4 material system
upconversion properties. Yet, there is no discussion as to the
quality or quantity of upconverted light to even suggest that the
amount produced could be useful for display or color enhancing
applications The materials described by Suyver et al are useful in
various embodiments of the invention.
[0067] FIG. 2 is a schematic reproduced from Suyver et al showing a
schematic energy level diagram of upconversion excitation and
visible emissions schemes for Er.sup.3+, Tm.sup.3+ and or Yb.sup.3+
ions. Full, dotted, dashed, and curly arrows indicate respectively
radiative, non-radiative energy transfer, cross relaxation and
other relaxation processes.
[0068] The lanthanide doped oxides differ from more traditional
multi-photon up conversion processes where the absorption of, for
example, two photons is needed in a simultaneous event to promote
an electron from a valence state directly into an upper level
conduction band state where relaxation across the band gap of the
material produces fluorescence. Here, the co-doping produces states
in the band gap of the NaYF.sub.4 such that the Yb.sup.3+ ion has
an energy state at .sup.2F.sub.5/2 pumpable by a single photon
event and from which other single photon absorption events can
populate even higher states. Once in this exited state, transitions
to higher energy radiative states are possible, from which light
emission will be at a higher energy than that of the incident light
pumping the .sup.2F.sub.5/2 energy state. In other words, the
energy state at .sup.2F.sub.5/2 of the Yb.sup.3+ ion is the state
that absorbs 980 nm light permitting a population build up serving
as the basis for the transitions to the higher energy states such
as the .sup.4F.sub.7/2 energy state. Here, transitions from the
.sup.4F.sub.7/2 energy state produce visible emissions.
[0069] Chen et al have described a four-photon upconversion in
Four-photon upconversion induced by infrared diode laser excitation
in rare-earth-ion-doped Y.sub.2O.sub.3 nanocrystals, Chemical
Physics Letters, 448 (2007) pp. 127-131 In that paper, emissions at
390 nm and at 409 nm were associated with a four-photon
upconversion process in the Y.sub.2O.sub.3 nanocrystals. FIG. 3
reproduced from Chen et al shows a ladder of states by which an
infrared light source can progressively pump until the
.sup.4D.sub.7/2 state is reached. From this upper state,
transitions downward in energy occur until the .sup.4G.sub.1/2
state is reached, where a transition downward in energy emits a 390
nm photon. The materials described by Chen et al are useful in
various embodiments of the invention.
[0070] The transitions from 390 nm, 410 nm, 564 nm, and 662 nm
represent potential emissions across the visible spectrum that
could for example enhance white light emission upon absorption of
light or energy from an IR light source, or depending on the
relative strengths for each of these emissions could be used to
enhance a particular color emission upon absorption of light or
energy from an IR light source.
[0071] U.S. Pat. No. 7,008,559 (the entire contents of which are
incorporated herein by reference) describes the upconversion
performance of ZnS where excitation at 767 nm produces emission in
the visible range. The materials described in U.S. Pat. No.
7,008,559 (including the ZnS as well as Er.sup.3+ doped BaTiO.sub.3
nanoparticles and Yb.sup.3+ doped CsMnCl.sub.3) are suitable in
various embodiments of the invention.
[0072] Further, materials specified for up conversion in the
invention include CdTe, CdSe, ZnO, CdS, Y.sub.2O.sub.3, MgS, CaS,
SrS and BaS. Such up conversion materials may be any semiconductor
and more specifically, but not by way of limitation, sulfide,
telluride, selenide, and oxide semiconductors and their
nanoparticles, such as Zn.sub.1-xMn.sub.xS.sub.y,
Zn.sub.1-xMn.sub.xSe.sub.y, Zn.sub.1-xMn.sub.xTe.sub.y,
Cd.sub.1-xMnS.sub.y, Cd.sub.1-xMn.sub.xSe.sub.y,
Cd.sub.1-xMn.sub.xTe.sub.y, Pb.sub.1-xMn.sub.xS.sub.y,
Pb.sub.1-xMn.sub.xSe.sub.y, Pb.sub.1-xMn.sub.xTe.sub.y,
Mg.sub.1-xMnS.sub.y, Ca.sub.1-xMn.sub.xS.sub.y,
Ba.sub.1-xMn.sub.xS.sub.y and Sr.sub.1-x, etc. (wherein,
0<x.ltoreq.1, and 0<y.ltoreq.1). Complex compounds of the
above-described semiconductors are also contemplated for use in the
invention--e.g. (M.sub.1-zN.sub.z).sub.1-xMn.sub.xA.sub.1-yB.sub.y
(M=Zn, Cd, Pb, Ca, Ba, Sr, Mg; N.dbd.Zn, Cd, Pb, Ca, Ba, Sr, Mg;
A=S, Se, Te, O; B.dbd.S, Se, Te, O; 0<x.ltoreq.1,
0<y.ltoreq.1, 0<z.ltoreq.1). Two examples of such complex
compounds are Zn.sub.0.4Cd.sub.0.4Mn.sub.0.2S and
Zn.sub.0.9Mn.sub.0.1S.sub.0.8Se.sub.0.2. Additional conversion
materials include insulating and nonconducting materials such as
BaF.sub.2, BaFBr, and BaTiO.sub.3, to name but a few exemplary
compounds. Transition and rare earth ion co-doped semiconductors
suitable for the invention include sulfide, telluride, selenide and
oxide semiconductors and their nanoparticles, such as ZnS; Mn; Er;
ZnSe; Mn, Er; MgS; Mn, Er; CaS; Mn, Er; ZnS; Mn, Yb; ZnSe; Mn,Yb;
MgS; Mn, Yb; CaS; Mn,Yb etc., and their complex compounds:
(M.sub.1-zN.sub.z).sub.1-x(Mn.sub.qR.sub.1-q).sub.xA.sub.1-yB.sub.y
(M=Zn, Cd, Pb, Ca, Ba, Sr, Mg; N.dbd.Zn, Cd, Pb, Ca, Ba, Sr, Mg;
A=S, Se, Te, O; B.dbd.S, . . . 0<z.ltoreq.1,
o<q.ltoreq.1).
[0073] Some nanoparticles such as ZnS:Tb.sup.3+, Er.sup.3+;
ZnS:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+,
Er3.sup.+; ZnS:Mn.sup.2+; ZnS:Mn,Er.sup.3+ are known in the art to
function for both down-conversion luminescence and upconversion
luminescence and would be suitable for the invention. In
up-conversion embodiments, light emitting particles which emit red
light may include praseodymium, light emitting particles which emit
green light may include erbium, and light emitting particles which
emit blue light may include thulium.
[0074] In general, the upconversion process generally requires one
of more rare-earth dopants, such as Er, Eu, Yb, Tm, Nd, Tb, Ce, Y,
U, Pr, La, Gd and other rare-earth species or a combination
thereof, doped into a dielectric crystal (of any size >0.1 nm),
including at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2, where
incident radiation is at longer wavelength than emissive radiation
from the crystal. The wavelength emitted in based entirely on the
dopant ion(s) chosen and their associated and relative contration
in the host crystal. For the example of upconversion in a
Y.sub.2O.sub.3 host crystal, to achieve a blue emission
(.about.450-480 nm) one could synthesize [Y.sub.2O.sub.3; Yb (3%),
Tm (0.2%)], where the Yb and Tm are the percentages doped in the
crystal relative to the Y atoms being 100%. Likewise, typical green
upconversion materials are [Y.sub.2O.sub.3; Yb (5%), Ho (1%)] and
[Y.sub.2O.sub.3; Yb (2%), Er (1%)] and [Y.sub.2O.sub.3; Yb (5%),
and typical red upconversion materials are [Y.sub.2O.sub.3; Yb
(10%), Er (1%)] and [Y.sub.2O.sub.3; Yb (5%), Eu (1%)]. The
concentrations of dopants relative to each other and the crystal
matrix must be tuned for every combination, and there are multiple
ways to achieve multiple colors from even the same dopants.
[0075] Up-conversion of red light with a wavelength of about 650 nm
in Tm.sup.3+ doped flourozirconate glasses can be used in the
invention to produce blue light. In this system, the blue light
consists of two emission bands; one at 450 nm which is ascribed to
the 1D2.fwdarw.3H4 transition, the others at 475 nm is ascribed to
the 1G4.fwdarw.3H6 transition. The emission intensities of both
bands have been observed by others to vary quadratically with the
excitation power. For glasses with a Tm.sup.3+ concentration of 0.2
mol % and greater, cross-relaxation processes occur which decrease
the up-conversion efficiency.
[0076] The emission of visible light upon excitation in the
near-infrared (NIR) has been observed in optically clear colloidal
solutions of LuPO.sub.4:Yb.sup.3+, Tm.sup.3+, and
YbPO.sub.4:Er.sup.3+ nanocrystals in chloroform. Excitation at 975
nm has been shown by others to produce visible luminescence in the
blue, green, or red spectral regions.
[0077] Tellurium and germanium oxides (tellurites and germinates)
are also suitable upconverters. These glasses can be doped with Tm,
Yb, Ho, Er, Pr, for example.
[0078] Yb.sup.3+ doped BaZrO.sub.3 is also suitable for
upconversion. Er.sup.3+ and/or Tm.sup.3+ doping is also suitable
for tailoring the emission wavelengths.
[0079] In another embodiment, Nd.sup.3+:Cs.sub.2NaGdCl.sub.6 and
Nd.sup.3+, Yb.sup.3+:Cs.sub.2NaGdCl.sub.6 polycrystalline powder
samples prepared by Morss method have been reported to be up
converters and are suitable for the present invention. These
materials, under 785 nm irradiation, have shown upconversion
emissions near 538 nm (Green), 603 nm (Orange), and 675 nm (Red)
were observed and assigned to 4G7/2.fwdarw.4I9/2,
(4G7/2.fwdarw.4I11/2; 4G5/2.fwdarw.4I9/2), and
(4G7/2.fwdarw.4I13/2; 4G5/2.fwdarw.4I11/2), respectively.
[0080] In another embodiment, Nd.sup.3+ and Ho.sup.3+ co-doped
-based ZrF.sub.4 fluoride glasses under 800 nm excitation have been
reported to be up converters and are suitable for the present
invention. Among the up-conversion luminescences for the ZrF.sub.4
fluoride glasses, the green emission was seen to be extremely
strong and the blue and red emission intensities were very
weak.
[0081] In another embodiment, Tm.sup.3+/Yb.sup.3+-codoped
TeO.sub.2--Ga.sub.2O.sub.3--R.sub.2O (R.dbd.Li, Na, K) glasses have
been reported to be up converters and are suitable for the present
invention. These materials, under excitation at 977 nm, showed
intense blue upconversion emission centered at 476 nm along with a
weak red emission at 650 nm.
[0082] In another embodiment, metal-to-ligand charge transfer
(MLCT) transition in [Ru(dmb).sub.3].sup.2+
(dmb=4,4'-dimethyl-2,2'-bipyridine) in the presence of anthracene
or 9,10-diphenylanthracene have been reported to be up converters
and are suitable for the present invention. Upconverted singlet
fluorescence resulting from triplet-triplet annihilation at low
excitation power has been reported. In particular
9,10-diphenylanthracene (DPA) (substituted for anthracene) showed
higher efficiencies for upconversion. In these experiments, workers
with this material system assumed that DPA's increased singlet
fluorescence quantum yield (=0.95) relative to anthracene (=0.27)7.
This work lead to an approximate 24.4.+-.6.1 enhancement of
green-to-blue light upconversion permitting direct visualization of
the process at low excitation power, for example by a commercial
green laser pointer (.lamda..sub.ex=532 nm, <5 mW peak
power).
[0083] FIG. 4A is a schematic of a depiction of an upconverter or a
down converter material (i.e., a photoactive material) according to
one embodiment of the invention.
[0084] FIG. 4A shows a number of structural configurations for
placement of a dielectric core upconverter or a down converter
material (which is of a nanometer sized scale) in proximity to a
metal shell. Incident light at a wavelength .lamda..sub.1 interacts
with the upconverting dielectric core. The interaction of light
.lamda..sub.1 with the dielectric core produces a secondary
emission at a frequency .lamda..sub.2 which has a shorter
wavelength than .lamda..sub.1 and accordingly has a higher energy
than .lamda..sub.1. While the exact physical mechanisms for the
upconversion may depend on the particular upconversion material and
process being used in a particular application, for the purposes
for discussion and illustration, the following explanation is
offered.
[0085] In the context of FIG. 4A, when a wavelength .lamda..sub.1
interacts with a dielectric material core, three separate processes
are well understood for the upconversion process involving
trivalent rare earth ions. These three processes are: [0086] 1)
excited state absorption whereby two photons are absorbed
sequentially by the same ion to excite and populate one or more
states; [0087] 2) energy transfer upconversion which is a transfer
of excitation from one ion to another already in an excited state;
and [0088] 3) a cooperative process of multiphotons where two
nearby ions in excited states are emitting collectively from a
virtual state. Regardless of which one of these processes is
occurring between the chosen ion(s) and the host lattice, the end
result is a photon of energy greater than the excitation energy
being emitted from the host lattice for the upconversion
process.
[0089] Therefore, the particular ion being activated (whether it be
a dopant ion or a host ion of a lattice such as in the neodymium
oxide) will be chosen based on the host material being processed,
in order that the dopant ion or the host ion in the dielectric core
provide ion states which are pumpable by a NIR source to generate
the resultant emission .lamda..sub.2.
[0090] Hence, the invention in one embodiment provides an
upconversion or a down conversion system including a nanoparticle
configured, upon exposure to a first wavelength .lamda..sub.1 of
radiation, to generate a second wavelength .lamda..sub.2 of
radiation having an energy higher or lower than the first
wavelength .lamda..sub.1. The system can include a metallic
structure disposed in relation to the nanoparticle (e.g. a metallic
shell covering a fraction of the nanoparticle). The system may
include a receptor disposed in the medium in proximity to the
nanoparticle. The receptor upon activation by the second wavelength
.lamda..sub.2 may itself fluoresce producing visible light. In one
embodiment of the invention, a physical characteristic of metallic
structure (such as those described above and below in the drawings)
is set to a value where a surface plasmon resonance in the metallic
structure resonates at a frequency which provides spectral overlap
with either the first wavelength .lamda..sub.1 or the second
wavelength .lamda..sub.2.
[0091] Within the context of the invention, the term "physical
characteristic" of the metallic shell or core can relate to any
characteristic of the metal itself or the shell or core dimensions
or shape which affects the surface plasmon resonance frequency.
Such physical characteristics can include, but are not limited to,
a conductivity, a radial dimension, a chemical composition or a
crystalline state of the metal shell or core.
[0092] In various embodiments, the metallic structures can be a
metallic shell encapsulating at least a fraction of the
nanoparticle in the metallic shell wherein a conductivity, a radial
dimension, or a crystalline state of the metallic shell sets the
surface plasmon resonance in the metallic structure to resonate at
a frequency which provides spectral overlap with either the first
wavelength .lamda..sub.1 or the second wavelength .lamda..sub.2. In
various embodiments, the metallic structures can be a multi-layer
metallic shell encapsulating at least a fraction of the
nanoparticle in the metallic shell wherein a conductivity, a radial
dimension, or a crystalline state of the metallic shell sets the
surface plasmon resonance in the metallic structure to resonate at
the first wavelength .lamda..sub.1 and the second wavelength
.lamda..sub.2. This capability permits radiation at .lamda..sub.1
and .lamda..sub.2 to be amplified.
[0093] In various embodiments, the metallic structures can be a
metallic particle existing in one or more multiple structures.
These multiple structures can have a variety of shapes including
for example sphere, spheroid, rod, cube, triangle, pyramid, pillar,
crescent, tetrahedral shape, star or combination thereof disposed
adjacent the nanoparticle wherein a conductivity, a dimension (e.g.
a lateral dimension or a thickness), or a crystalline state of the
metallic structure sets the surface plasmon resonance in the
metallic particle or rod to resonate at a frequency which provides
spectral overlap with either the first wavelength .lamda..sub.1 or
the second wavelength .lamda..sub.2. Such shapes are described in
the present figures and in the figures in U.S. Ser. No. 12/401,478
which is incorporated by reference in its entirety. The shape
choice can affect the frequency of the surface plasmon resonance.
It is known that the plasmon band is changed by the shape of
nanoparticles (e.g., prolate and obloid spheroids). The paper
"Spectral bounds on plasmon resonances for Ag and Au prolate and
oblate nanospheroids," in the Journal of Nanophotonics, Vol. 2,
029501 (26 Sep. 2008), the entire contents of which are
incorporated by reference, shows plasmon resonance shifts for
shaping of Ag and plasmon resonance shifts for shaping of Au of
prolate and obloid spheroids. In one embodiment of the invention,
with an increasing aspect ratio for a metallic structure of the
invention, the prolate spheroid resonance is red shifted relative
to a sphere with no lower limit (under the assumptions of a Drude
dispersion model). On the other hand, the oblate resonances are
"blue shifted" as the spheroid becomes increasingly flat, but up to
a limit.
[0094] In various embodiments, the metallic structures can be a
metallic structure disposed interior to the nanoparticle wherein a
conductivity or a dimension (e.g. a lateral dimension or a
thickness) of the metallic structure sets the surface plasmon
resonance in the metallic structure to resonate at a frequency
which provides spectral overlap with either the first wavelength
.lamda..sub.1 or the second wavelength .lamda..sub.2. In various
embodiments, the metallic structures can be a metallic multi-layer
structure disposed interior to the nanoparticle wherein a
conductivity or a dimension (e.g. a lateral dimension or a
thickness) of the metallic structure sets the surface plasmon
resonance in the metallic structure to resonate at the first
wavelength .lamda..sub.1 and the second wavelength .lamda..sub.2.
This capability once again permits radiation at .lamda..sub.1 and
.lamda..sub.2 to be amplified.
[0095] In another embodiment, the invention provides a nanoparticle
structure including a sub 1000 nm dielectric core and a metallic
structure disposed in relation to the nanoparticle. The dielectric
core includes at least one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S,
NaYF.sub.4, NaYbF.sub.4, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or SiO.sub.2. Such
nanoparticle structures can exhibit in certain embodiments surface
plasmon resonance in the metallic structures to enhance
upconversion of light from a first wavelength .lamda..sub.1 to a
second wavelength .lamda..sub.2.
[0096] As described above, a shell (or other structure) is in
particular designed with a layer thickness (or for example a
lateral dimension) to enhance the photon upconversion process
through plasmonic enhancement. The thickness of the shell (or other
physical characteristic) is "tuned" in its thickness to the
absorption process by having a dimension in which plasmons (i.e.,
electrons oscillations) in shell have a resonance in frequency
which provides spectral overlap with the absorption band targeted.
Thus, if the upconversion is to be stimulated by 980 nm NIR light,
then the thickness of the shell is "tuned" in a thickness to where
a plasmon resonance resonates at a frequency also of 980 nm (or in
the neighborhood thereof as plasmon resonances are typically broad
at these wavelengths).
[0097] Such a plasmon resonating shell can be made of numerous
transition metals, including though not limited to gold, silver,
platinum, palladium, nickel, ruthenium, rhenium, copper, and cobalt
or a combination or alloys or layers thereof. Such a plasmon
resonating shell can be also made of a combination of metals and
non-metals. When formed of a gold nanoshell, the recommended
thickness to resonate with 980 nm light is approximately 3.5 nm
surrounding an 80 nm upconverting core, as projected by extended
Mie theory calculations. (See Jain et al., Nanolett. 2007, 7(9),
2854 the entire contents of which are incorporated herein by
reference.) FIG. 4B is reproduced from Jain et al and illustrates
the capability in the invention to "tune" the metal shell to have a
spectral overlap with the excitation and/or emission radiation
wavelengths. This capability of matching or tuning of the
frequencies provides an enhancement of the absorption which would
not be present with a dielectric core alone.
[0098] In one embodiment of the invention, the metallic structures
can be an alloy such as for example a Au:Ag alloy. The alloy
content can be set to adjust the frequency of the surface plasmon
resonance. In one embodiment of the invention, the metallic
structures can be an alloy such as for example a Pt:Ag alloy. The
alloy content can be set to adjust the frequency of the surface
plasmon resonance. In one embodiment of the invention, the metallic
structures can be an alloy such as for example a Pt:Au alloy. The
alloy content can be set to adjust the frequency of the surface
plasmon resonance.
[0099] In one embodiment of the invention, the nanoparticle can be
an alloy of two or more materials. In this embodiment, the alloy
can have a composition between the two or more materials which is
set to a compositional value where excitation of the alloy at first
wavelength .lamda..sub.1 produces emission at the second wavelength
.lamda..sub.2. In one embodiment of the invention, the nanoparticle
can be a zinc sulfide and zinc selenide alloy. In one embodiment of
the invention, the nanoparticle can be a zinc sulfide and cadmium
sulfide alloy.
[0100] In one embodiment of the invention, the zinc sulfide and
zinc selenide nanoparticle alloy can have an alloy content set to
provide a predetermined surface plasmon resonance. In one
embodiment of the invention, the zinc sulfide and cadmium sulfide
nanoparticle alloy can have an alloy content is set to provide a
predetermined surface plasmon resonance.
[0101] Some techniques for producing nanoparticles and nanoparticle
alloys which are suitable for the invention are described in the
following documents, all of which are incorporated herein in their
entirety: U.S. Pat. Nos. 7,645,318; 7,615,169; 7,468,146;
7,501,092; U.S. Pat. Appl. Publ. No. 2009/0315446; 2008/0277270;
2008/0277267; 2008/0277268; and WO 2009/133138.
[0102] In one embodiment of the invention, the nanoparticle can be
a dielectric or semiconductor configured to generate an up
converted or down converted wavelength .lamda..sub.2. In one
embodiment of the invention, the nanoparticle can include multiple
dielectrics or semiconductors respectively configured to emit at
different wavelengths for .lamda..sub.2. In one embodiment of the
invention, multiple nanoparticles having different dielectrics or
semiconductors can be included in a mixture of the nanoparticles
dispersed in the medium.
[0103] In one embodiment of the invention, the thickness of the
metal shell is set depending on the absorption frequency (or in
some cases the emission frequency) of the particular dopant ions in
the dielectric core to enhance the total efficiency of the emission
process of the upconverted light. Accordingly, the thickness of the
shell can be considered as a tool that in one instance enhances the
absorption of .lamda..sub.1, and in another instance can be
considered as a tool that enhances the emission of .lamda..sub.2,
or in other situations can be considered an enhancement feature
that in combination enhances the overall net process.
[0104] Additionally, plasmon-phonon coupling may be used to reduce
a resonance frequency through the tuning of the bands to a degree
off resonance. This may be useful in optimizing resonance energy
transfer processes for the purpose of shifting the outputted color
to a color desirable for a painted, colored, or displayed surface.
In one example, FIG. 5 shows an example of the plasmon resonance
shift as a function of shell thickness.
[0105] Here, in one embodiment of the invention, the capability to
produce stimulated emission at a targeted wavelength or color is
complemented by the ability to design nanoparticles for the color
enhancing compositions that have designed absorption bands.
[0106] Such absorption materials could for example further serve to
improve the color purity of light observed from a paint, ink, dye,
or otherwise reflecting surface treated with the color enhancing
compositions of the invention.
[0107] Details of the preparation of this nanoparticle system are
included in U.S. Ser. No. 12/725,108, the entire contents of which
are incorporated herein by reference. The absorption spectrum of
Y.sub.2O.sub.3 alone (lower trace) is fairly featureless, showing
absorption due to the tri-arginine near 200 nm and a gentle slope
associated with scattering and absorption by the Y.sub.2O.sub.3
nanoparticles extending into the visible portion of the spectrum.
The gold-coated Y.sub.2O.sub.3 (upper trace), on the other hand,
exhibit a strong absorption band at 546 nm, which is characteristic
of the plasmonics resonance band due to the gold shell around the
Y.sub.2O.sub.3 cores. The red-shifting of the plasmon absorption to
546 nm is consistent with the presence of a gold shell around a
dielectric core.
[0108] In one embodiment of the invention, the materials for the
upconverter dielectric core can include a wide variety of
dielectric materials, as described above. In various embodiments of
the invention, the upconverter dielectric core includes more
specifically lanthanide doped oxide materials. Lanthanides include
lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd),
promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd),
terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium
(Tm), ytterbium (Yb), and lutetium (Lu). Other suitable dielectric
core materials include non-lanthanide elements such as yttrium (Y)
and scandium (Sc). Hence. suitable dielectric core materials
include Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4, NaYbF.sub.4,
Na-doped YbF.sub.3, YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3,
LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2, LuPO.sub.4, YVO.sub.4,
YbF.sub.3, YF.sub.3, or SiO.sub.2. These dielectric cores can be
droped with Er, Eu, Yb, Tm, Nd, Tb, Ce, Y, U, Pr, La, Gd and other
rare-earth species or a combination thereof.
[0109] Lanthanides usually exist as trivalent cations, in which
case their electronic configuration is (Xe) 4f.sup.n, with n
varying from 1 (Ce.sup.3+) to 14 (Lu.sup.3+). The transitions
within the f-manifold are responsible for many of the
photo-physical properties of the lanthanide ions, such as
long-lived luminescence and sharp absorption and emission lines.
The f-electrons are shielded from external perturbations by filled
5s and 5p orbitals, thus giving rise to line-like spectra. The f-f
electronic transitions are LaPorte forbidden, leading to long
excited state lifetimes, in the micro- to millisecond range.
[0110] Accordingly, examples of doped materials in the invention
include oxides such as yttrium oxide and neodymium oxide and
aluminum oxide as well as sodium yttrium fluoride and
nanocrystalline perovskites and garnets such as yttrium aluminum
garnet (YAG) and yttrium aluminum perovskite (YAP). Of these
materials, doping is required for some, but not all of these
materials, for promoting upconversion efficiencies. In various
embodiments of the invention, the host nanocrystals are doped with
trivalent rare earth lanthanide ions from those lanthanide series
elements given above.
[0111] More specifically, in various embodiments of the invention,
pairs of these dopants are introduced in order to make accessible
more energy states in the host crystal. The activation and pumping
of these energy states follows closely the principles discussed
above with regard to FIG. 3. Doping concentrations in the invention
can range from 0.2% to 20% roughly per ion into the host lattice or
in a weight or mol % variation. The efficiency of the upconversion
processes of specific bands in these materials can be modulated by
the percentages doped to induce and enhance targeted emissions.
Lanthanide doped upconverters while not limited to, can use the
following mol percent dopant compositions: 5% Er, 10% Yb, 0.2%
Tm+3% Yb, and 1% Er+10% Yb.
[0112] The size of the nanocrystal will also have an effect on the
efficiency of the upconversion process, as a larger nanocrystal
will have more sites for dopant ions to be accommodated into the
host lattice, therefore enabling more emissions from the same doped
host than if the nanocrystal were smaller. While the dopant
percentages listed above are not rigidly fixed, these numbers
provide a rudimentary teachings of the typical percentages one
would use in obtaining a particular dielectric core material of the
invention.
[0113] Moreover, some of these host crystals (e.g., neodymium
oxide) in one embodiment of the invention may require no specific
doping to facilitate upconversion, which has been seen in one
instance in Nd.sub.2O.sub.3 with an excitation wavelength of 587 nm
producing emissions at 372 nm, 402 nm, and 468 nm. See Que, W et
al. Journal of Applied Physics 2001, vol 90, pg 4865, the entire
contents of which are incorporated herein by reference. Doping
neodymium oxide with Yb.sup.3+, in one embodiment of the invention,
would enhance upconversion through sensitizing the Nd.sup.3+ ions
with a lower energy Yb.sup.3+ activator.
[0114] In one embodiment of the invention, the dielectric core is
coated, such as for example with a metallic shell, to enhance
electron-phonon coupling and thereby increase upconversion or down
conversion efficiency, as discussed above. In another embodiment of
the invention, the shell can include a SiO.sub.2-- and/or
TiO.sub.2-coating, and this coating is in one embodiment coated on
doped Y.sub.2O.sub.3 upconverting nanoparticles to thereby, in some
instances, increase the upconversion efficiency relative to an
uncoated nanocrystal. In another embodiment of the invention, the
shell can include a SiO.sub.2-- and/or TiO.sub.2-coating, and this
coating is in one embodiment coated on doped Y.sub.2O.sub.3 down
converting nanoparticles to thereby, in some instances, increase
the down conversion efficiency relative to an uncoated nanocrystal.
Further, in one embodiment of the invention, the coating can be a
polymer. In one embodiment, this coating is provided on
NaYF.sub.4:Ln/NaYF.sub.4 dielectric core. Such coatings can
increase the upconversion efficiency relative to an uncoated
upconverter.
[0115] In another embodiment of the invention, phonon modes of an
undoped host-lattice (e.g., Y.sub.2O.sub.3) nanocrystals are
modulated, for example, by Au, Ag, Pt, and Pd shells of varying
thicknesses. In various embodiments of the invention, the
upconverter dielectric core and the shell system includes as
upconverting nanocrystals Y.sub.2O.sub.3:Ln with NaYF.sub.4 shells,
Y.sub.2O.sub.3:Ln with Au(Ag,Pt) shells, NaYF.sub.4:Ln with
Y.sub.2O.sub.3 shells, NaYF.sub.4:Ln with Au(Ag,Pt) shells. In this
system, the core diameter and shell outer/inner diameter of the
metallic coatings can be set to dimensions that are expected to be
tunable to a plasmon mode overlap.
[0116] In other embodiments as discussed below, the metal coating
or the metallic structure can exist inside the dielectric and the
relative position of the metal structure to the dielectric
structure can enhance plasmon resonance. These structures with the
metallic structure inside can be referred to as a metallic core up
converter or a metallic core down converter. The metallic core
technique for energy conversion is useful since it takes advantage
of metal nano-particles that have improved surface morphology
compared to shell coatings on core dielectrics. The metal or
metallic alloy in the inner core metallic energy converter can be
selected to tune its plasmonic activity. These structures with the
metallic structure outside can be referred to as a core up
converter or a core down converter.
[0117] In various embodiments of the invention, the upconverter or
down converter dielectric core can be coated with thiol-terminated
silanes to provide a coating of SiO.sub.2 about the core of similar
reactivity to Y.sub.2O.sub.3. In one embodiment of the invention,
the above-described methodology is used to synthesize core-shell
nanoparticles of Y.sub.2O.sub.3:Ln with NaYF.sub.4 shells,
Y.sub.2O.sub.3:Ln with Au(Ag,Pt) shells, NaYF.sub.4:Ln with
Y.sub.2O.sub.3 shells, NaYF.sub.4:Ln with Au(Ag,Pt) shells where
core and shell diameters varying from 2 to 20 nm. In these material
systems, the tuned ratio of core-to-shell diameter may permit a
plasmon-phonon resonance which should amplify absorption of NIR
light and/or upconverted emission. In these material systems,
control of the core and shell diameters is one factor determining
the size dependent effect and subsequent tuning of plasmon-phonon
resonance.
[0118] In one embodiment of the invention, the upconverter
dielectric core can be mixed core-shell materials including for
example semiconducting Y.sub.2O.sub.3 and NaYF.sub.4 cores doped
with various Ln series metals, which have been shown to possess
large upconverting efficiencies. These doped Y.sub.2O.sub.3 and
NaYF.sub.4 cores will have shells of Au(Ag,Pt, Pd) or undoped
Y.sub.2O.sub.3 and NaYF.sub.4 matrices which have the potential to
enhance or tune the phonon modes needed for energy transfer in the
upconversion process. Solubility can be enhanced, for example, by
addition of thiolated organics (Au shell), organic chain
triethanolsilane (Y.sub.2O.sub.3 shell), and trioctylphospine-oleic
amine (NaYF.sub.4 shell). All core-shell nanoparticles may further
be solublized into a colloidal suspension with the addition of
triarginine peptide, polyethylene glycol, and polyethyleneimine
surfactants.
[0119] FIG. 6A shows some of the various embodiments of the
upconverter structures of the invention that can be designed: (a) a
structure including upconverter (UC) molecules bound to a metal
(gold) nanoparticle; (b) a structure including an UC-containing
nanoparticle covered with metal nanoparticles, (c) a metal
nanoparticle covered with an UC-containing nanocap; (d) an
UC-containing nanoparticle covered with metal nanocap, (e) a metal
nanoparticle covered with UC nanoshell, (f) an UC-containing
nanoparticle covered with metal nanoshell, (g) an UC-containing
nanoparticle covered with metal nanoshell with protective coating
layer.
[0120] The configurations (while shown in the FIG. 6 series with
UC-containing materials) would be applicable for enhancement for
down converting materials such as the quantum dots described above.
Moreover, in one embodiment of the invention, dielectric spacers
(for examples silicates as discussed below) can be used with the
structure of FIG. 6A-b to space apart the particle type metallic
structures. In another embodiment of the invention, dielectric
spacers can be used with the structure of FIG. 6A-d, f to space
apart the metal layers, whether or not these layers are partial
metal layers as in FIG. 6A-d or continuous metal layers as in FIG.
6A-f. See FIGS. 6B-b, d, and f.
[0121] The plasmonic properties of various metallic structures,
which have been investigated in the art and are suitable for the
invention, include metallic nanoshells of spheroidal shapes [S. J.
Norton and T. Vo-Dinh, "Plasmonic Resonances of Nanoshells of
Spheroidal Shape", IEEE Trans. Nanotechnology, 6, 627-638 (2007)],
oblate metal nanospheres [S. J. Norton, T. Vo-Dinh, "Spectral
bounds on plasmon resonances for Ag and Au prolate and oblate
nanospheroids", J. Nanophotonics, 2, 029501 (2008)], linear chains
of metal nanospheres [S. J. Norton and T. Vo-Dinh, "Optical
response of linear chains of metal nanospheres and nanospheroids",
J. Opt. Soc. Amer., 25, 2767 (2008)], gold nanostars [C. G. Khoury
and T. Vo-Dinh, "Gold Nanostars for Surface-Enhanced Raman
Scattering: Synthesis, Characterization and Applications", J. Phys.
Chem C, 112, 18849-18859 (2008)], nanoshell dimmers [C. G. Khoury,
S. J. Norton, T Vo-Dinh, "Plasmonics of 3-D Nanoshell Dimers Using
Multipole Expansion and Finite Element Method, ACS Nano, 3,
2776-2788 (2009)], and multi-layer metallic nanoshells [S. J.
Norton, T. Vo-Dinh, "Plasmonics enhancement of a luminescent or
Raman-active layer in a multilayered metallic nanoshell", Applied
Optics, 48, 5040-5049 (2009)]. The entire contents of each of the
above noted references in this paragraph are incorporated herein by
reference. In various embodiments of the invention, multi-layer
metallic nanoshells discussed in this application have the
potential capability to enhance electromagnetically two spectral
regions. Accordingly, the metallic structures of the invention can
be used in the upconverting mode to enhance both the excitation at
wavelength .lamda..sub.1 and the emission at wavelength
.lamda..sub.2 This feature also can be used in the down converting
to enhance primarily the emission at wavelength .lamda..sub.2 and
potentially the excitation at wavelength .lamda..sub.1.
[0122] Such metallic structures in various embodiments of the
invention include conducting materials made for example of metals,
or doped glasses or doped semiconductors. These conducting
materials can be in the form of pure or nearly pure elemental
metals, alloys of such elemental metals, or layers of the
conducting materials regardless of the constituency. The conducting
materials can (as noted above) include non-metallic materials as
minor components which do not at the levels of incorporation make
the composite material insulating.
[0123] Similarly, in various embodiments of the invention, the up
or down converting materials can include at least one of a
dielectric, a glass, or a semiconductor. The up or down converting
materials can include an alloy of two or more dielectric materials,
an alloy of two or more glasses, or an alloy of two or more
semiconductors.
[0124] Accordingly, FIG. 6A represents embodiments of the invention
where the dielectric core is supplemented with a shell. The shell
can include a metal layer of a prescribed thickness. The metal
layer can include materials such as nickel, gold, iron, silver,
palladium, platinum and copper and combinations thereof. The metal
layer can be also made of a combination of metals and non-metals.
The shell functions as a plasmonic shell where surface plasmons can
form in the metal between the dielectric core and the outer
environment acting as an exterior dielectric. The shell (as shown)
may not be a complete shell. Partial metallic shells or metallic
shells of varying thicknesses are also acceptable in the
invention.
[0125] As discussed below, the metallic shells in another
embodiment of the invention serve as scattering centers for UV
light where UV light which, even if absorbed in a paint or coating
layer contributes at a minimum to localized heating of the paint or
coating layer material, will be scattered from the paint or coated
layer.
[0126] FIG. 6B shows yet other embodiments of upconversion
structures that have a dielectric layer between the metal and the
UC materials.
[0127] FIG. 6C shows still further embodiments of plasmonics-active
nanostructures having upconverting (UC) materials that can be
designed: (a) a metal nanoparticle, (b) an UC nanoparticle core
covered with metal nanocap, (c) a spherical metal nanoshell
covering an UC spheroid core, (d) an oblate metal nanoshell
covering UC spheroid core, (e) a metal nanoparticle core covered
with UC nanoshell, (f) a metal nanoshell with protective coating
layer, (g) multi layer metal nanoshells covering an UC spheroid
core, (h) multi-nanoparticle structures, (i) a metal nanocube and
nanotriangle/nanoprism, and (j) a metal cylinder.
[0128] FIG. 6D shows yet other embodiments of plasmonics-active
nanostructures having upconverting materials with linked
photo-active (PA) molecules that can be designed. For example, for
the case of psoralen (as the PA molecule), the length of the linker
between the PA molecule and the UC material or the metal surface is
tailored such that it is sufficiently long to allow the PA
molecules to be active (attach to DNA) and short enough to allow
efficient excitation of light from the UC to efficiently excite the
PA molecules. FIG. 6D shows (a) PA molecules bound to an UC
nanoparticle, (b) an UC material-containing a nanoparticle covered
with metal nanoparticles, (c) a metal nanoparticle covered with UC
material nanocap, (D) an UC material-containing nanoparticle
covered with metal nanocap, (e) a metal nanoparticle covered with
an UC material nanoshell, (f) an UC material-containing
nanoparticle covered with metal nanoshell, (g) an UC
material-containing nanoparticle covered with metal nanoshell with
protective coating layer.
[0129] With the upconverter and down converter structures of the
invention, a plasmonics effect is advantageous. A plasmonics effect
can increase the local intensity of the received light or the local
intensity of the emitted light from the up and/or down converter
structures of the invention. A plasmonics effect can occur
throughout the electromagnetic region provided the suitable
nanostructures, nanoscale dimensions, metal types are used.
Plasmonic effects are possible over a wide range of the
electromagnetic spectrum, ranging from gamma rays and X rays
throughout ultraviolet, visible, infrared, microwave and radio
frequency energy. However, for practical reasons, visible and NIR
light are used for metal structures such as for example silver and
gold nanoparticles, since the plasmon resonances for silver and
gold occur in the visible and NIR region, respectively.
[0130] The color-shifting structures of the invention include in
various embodiments nanoparticles of neodymium and ytterbium doped
yttrium oxide, europium and ytterbium doped yttrium oxide, and any
combination of rare earth trivalent ions doped into a neodymium
oxide nanocrystal. The dual doped yttrium oxide of composition
neodymium and ytterbium and also the dual doped europium and
ytterbium are new for the yttrium oxide host lattice, although such
dual doped systems have been shown to work in other host lattices
such as YAG.
[0131] These dual doped lanthanide glasses have been shown to
upconvert efficiently on bulk materials, and thereby can provide
new upconverter structures at the nano-scale. There are a number of
advantages offered by these yttrium oxide nanostructures of the
invention. The small scale synthetic methodology for creating
nanoscale yttrium oxide is easier to control and produce in yttrium
oxide than in YAG. The host structure of yttrium oxide scintillates
by down conversion. These combinations of dopants in yttrium oxide
for example can provide predetermined emission colors for the
yttrium oxide nanocrystal for the color shifting of the
invention.
[0132] In one embodiment of the invention, a dual dopant permits
excitation of either ion in the host glass. For instance,
excitation by 980 nm light excites an ytterbium ion, where through
transfer of energy from one excited state of the ytterbium ion to
another dopant provides a mechanism for upconversion emission of
light in the visible and NIR spectral regions.
[0133] Up-conversion phosphors similar in chemical compositions to
the down-conversion fluorescent materials discussed above can be
used. The up-conversion phosphors can include laser dyes, e.g., the
organic small molecules that can be excited by the absorption of at
least two infrared photons with emission of visible light. The
up-conversion phosphors can include fluorescent polymers, e.g., the
class of polymers that can be excited by the absorption of at least
two infrared photons with emission of visible light. The
up-conversion phosphors can include inorganic or ceramic particles
or nano-particles, including the conventional up-conversion
phosphors (e.g. metal fluorides, metal oxides) that can be excited
by the absorption of at least two infrared photons with emission of
visible light. The up-conversion phosphors can include
semiconductor particles, including nano-particles such as II-VI or
III-V compound semiconductors, e.g. quantum dots, described in
details in the "down-conversion" semiconductors above.
[0134] Fluorescent up-conversion inorganic phosphors can include
but are not limited to metal oxides, metal halides, metal
chalcoginides (e.g. sulfides), or their hybrids, such as metal
oxo-halides, metal oxo-chalcoginides. Fluorescent up-conversion
inorganic phosphors are usually doped with rare earth elements
(e.g. Yb.sup.3+, Er.sup.3+, Tm.sup.3+). Some host examples include,
but are not limited to: NaYF.sub.4, YF.sub.3, BaYF.sub.5,
LaF.sub.3, La.sub.2MOO.sub.8, LaNbO.sub.4, LnO.sub.2S; where Ln is
the rare earth elements, such as Y, La, Gd).
[0135] These up conversion and down conversion materials, according
to the invention, are a mixture of color emitters configured to
emit, upon exposure to a light source, visible light at a first
wavelength .lamda..sub.1 in response to absorption of light or
energy across a band of wavelengths inside and outside the visible
spectrum. The visible light emission is enhanced relative to an
amount of light which would be emitted only by reflection of the
first wavelength .lamda..sub.1.
[0136] The color emitters particles can have a diameter less than
about 1000 nanometers. The light emitting particles (up or down)
can include a metallic structure disposed in relation to the
particle. A physical characteristic of the metallic structure is
set to a value where a surface plasmon resonance in the metallic
structure resonates at a frequency which provides spectral overlap
with either the first wavelength .lamda..sub.1. The physical
characteristic of the metallic structure is set to a value where a
surface plasmon resonance in the metallic structure resonates at a
frequency which provides enhanced emission at the first wavelength
.lamda..sub.1.
[0137] As detailed below, the mixture of color-emitters can be
attached to a dye molecule of a display. The mixture of
color-emitters can be a color emitting pixel display element. The
mixture of color-emitters can be a component of a color filter. The
mixture of color-emitters can be a component of a color filter for
a display. The mixture of color-emitters can be a component of a
colored surface. The mixture of color-emitters can be a component
of a colored reflective surface. The mixture of color-emitters can
be a component of a colored reflective surface in a pixel for a
display. The mixture of color-emitters can be a component of a
white-light emitting pixel display element. The mixture of
color-emitters can be a paint component. The mixture of
color-emitters can be a component disposed on glass beads in a
retroreflective paint. The mixture of color-emitters can be a
component of a binder layer securing glass beads in a
retroreflective paint to a base paint. The mixture of
color-emitters can be an ink component.
[0138] The mixture of color-emitters can be at least one of red,
blue, and green emitters configured to produce red, blue, and green
emissions from an up conversion process. The mixture of
color-emitters can be at least one of red, blue, and green emitters
configured to produce red, blue, and green emissions from a down
conversion process. The mixture of color-emitters can be at least
one of red, blue, and green emitters configured to produce red,
blue, and green emissions from a mixture of up converters and down
converters.
[0139] The mixture of color-emitters can be fluorescent emitters
including at least one of europium, terbium, cerium, and erbium or
combinations thereof The mixture of color-emitters can include a
first material configured to emit a first visible color in response
to absorption of ultraviolet light and a second material configured
to emit a second visible color in response to absorption of
infrared light, wherein the second visible color is different from
the first visible color. The mixture of color-emitters can include
a third material configured to emit a third visible color in
response to absorption of the ultraviolet light, wherein the third
visible color is different from the first visible color and the
second visible color. The first visible color, the second visible
color, and the third visible color can be the primary colors or a
mixture of the primary colors. Alternatively or in addition, the
mixture of color-emitters can include a third material configured
to emit a third visible color in response to absorption of the
infrared light. The third visible color can be different from the
first visible color and the second visible color.
[0140] The mixture of color-emitters can include a first material
configured to emit a first visible color in response to absorption
of ultraviolet light and a second material configured to emit a
second visible color in response to absorption of infrared light.
The second visible color can be substantially the same color as the
first visible color. The mixture of color-emitters can include a
third material configured to emit a third visible color in response
to absorption of the ultraviolet light. The third visible color can
be different from the first visible color and the second visible
color. Alternatively or in addition, the mixture of color-emitters
can include a third material configured to emit a third visible
color in response to absorption of the infrared light. The third
visible color can be different from the first visible color and the
second visible color. The first visible color, the second visible
color, and the third visible color can be the primary colors or a
mixture of the primary colors.
[0141] The mixture of color-emitters can include a metallic
structure disposed in relation to a nanoparticle emitter. The
metallic structure can be a metallic shell including at least one
of a spherical shell, an oblate shell, a crescent shell, or a
multilayer shell. The metallic structure can be at least one of Au,
Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al, Ga, or a combination or alloys
or layers thereof. The nanoparticle emitter can be at least one of
Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4, NaYbF.sub.4, YAG, YAP,
Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3, La.sub.2O.sub.3, TiO.sub.2,
LuPO.sub.4, YVO.sub.4, YbF.sub.3, YF.sub.3, Na-doped YbF.sub.3, or
SiO.sub.2 or alloys or layers thereof. The nanoparticle emitter can
include a dopant including at least one of Er, Eu, Yb, Tm, Nd, Tb,
Ce, Y, U, Pr, La, Gd and other rare-earth species or a combination
thereof. The dopant can have a concentration of 0.01%-50% by mol
concentration.
[0142] The color-emitters can be a down converter including at
least one of Y.sub.2O.sub.3; ZnS; ZnSe; MgS; CaS; Mn, Er ZnSe; Mn,
Er MgS; Mn, Er CaS; Mn, Er ZnS; Mn,Yb ZnSe; Mn,Yb MgS; Mn, Yb CaS;
Mn,Yb ZnS:Tb.sup.3+, Er.sup.3+; ZnS:Tb.sup.3+;
Y.sub.2O.sub.3:Tb.sup.3+; Y.sub.2O.sub.3:Tb.sup.3+, Er3.sup.+;
ZnS:Mn.sup.2+; ZnS:Mn,Er.sup.3+, alkali lead silicate including
compositions of SiO.sub.2, B.sub.2O.sub.3, Na.sub.2O, K.sub.2O,
PbO, MgO, or Ag, and combinations or alloys or layers thereof The
color-emitters can be a dielectric up converter including at least
one of Y.sub.2O.sub.3, Y.sub.2O.sub.2S, NaYF.sub.4, NaYbF.sub.4,
YAG, YAP, Nd.sub.2O.sub.3, LaF.sub.3, LaCl.sub.3, La.sub.2O.sub.3,
TiO.sub.2, LuPO.sub.4, YVO.sub.4, YbF.sub.3, YF.sub.3, Na-doped
YbF.sub.3, or SiO.sub.2 or alloys or layers thereof The dielectric
up converter can have a particle diameter ranging from at least one
of 2-1000 nm, 2-100 nm, 2-50 nm, 2-20 nm, or 2-10 nm. The
dielectric up converter can include a dopant of at least one of Er,
Eu, Yb, Tm, Nd, Tb, Ce, Y, U, Pr, La, Gd and other rare-earth
species or a combination thereof The dopant can have a
concentration of 0.01%-50% by mol concentration. A metallic
structure can be disposed in relation to the dielectric up
converter, and the metallic structure includes at least one of Au,
Ag, Cu, Ni, Pt, Pd, Co, Ru, Rh, Al, Ga, or alloys or layers
thereof. The dielectric up converter can be configured to exhibit
visible emission upon interaction with NIR light.
[0143] Coating Applications: Almost all surfaces of products
exposed to our environment are either coated, painted, stained, or
sealed with a protect that helps the underlying material resist
deterioration from the environmental factors such as sun, wind,
raid, moisture, salt, acid, and alkali exposure. Stainless steel,
aluminum, and copper are a few examples of materials who do not
necessarily require a coated, painted, stained, or sealed
protective layer. The coated surfaces are almost always of a
particular color chosen to improve the attractiveness of the
object.
[0144] As described at
http://www.howeverythingworks.org/supplements/paint.pdf, pigment
particles in paint are responsible for the opacity or color of the
paint. Pure white paint has pigment that absorbs no light but
rather scatters light in random directions. White pigment particles
are clear and have relatively high refractive indices. The pigment
particles are embedded in a polymer layer. As light tries to pass
through the paint, part of the light is reflected at every boundary
between polymer and pigment, and almost none of the light reaches
the back of the layer. Because the pigment particles in the paint
are typically rough and randomly oriented, the pigment particles
scatter the light in every direction making the paint appear to be
white. This high reflectivity gives paint its hiding power--its
ability to prevent light from reaching the material beneath the
paint and then returning to paint's surface.
[0145] Paints with very high refractive index pigments are best at
hiding the surfaces they cover. Absorption of light in the pigments
will give the paint. For example, a pigment which absorbs blue
light will give the paint a yellow tint. The reflected light has a
color characteristic of the non-absorbed colors of the spectrum. In
other words, colored pigments give paints their colors by
selectively absorbing some of the spectrum of light striking the
paint.
[0146] U.S. Pat. No. 4,283,320 (the entire contents of which are
incorporated herein by reference) describes an opacified latex
paint having small particle film-forming latex binders in
combination with minor amounts of opacifying pigment, and
substantial amounts of non-film-forming polymeric particles
(plastic pigment) provides a semi-gloss latex paint composition
having excellent hard enamel surfaces along with desirable film
integrity properties. The plastic pigment particles in U.S. Pat.
No. 4,283,320 are between about 0.1 and 0.5 microns and contain 0.2
to 2% copolymerized monomers containing carboxylic acid groups. The
semi-gloss plastic pigment latex paint of U.S. Pat. No. 4,283,320
is compounded at pigment-volume-content (PVC) between about 30% and
45% and considerably higher than conventional high quality enamel
latex paints. Into the latex paint of U.S. Pat. No. 4,283,320 or
onto painted surface of U.S. Pat. No. 4,283,320, in one embodiment
of the invention, the color enhancing mixtures described herein are
applied.
[0147] U.S. Pat. No. 5,134,186 (the entire contents of which are
incorporated herein by reference) describes a paint having a film
former and polymeric composition. The polymeric composition
comprises about 30 to about 50 weight percent of a substantially
non-self-polymerizable monomer and about 50 to about 70 weight
percent of a copolymerizable monomer having a water-soluble
homopolymer. Into the latex paint of U.S. Pat. No. 5,134,186 or
onto painted surface of U.S. Pat. No. 5,134,186, in one embodiment
of the invention, the color enhancing mixtures described herein are
applied.
[0148] U.S. Pat. No. 4,789,694 (the entire contents of which are
incorporated herein by reference) describes a paint coating
composition having a cationic free, functional emulsion polymer
mixture adapted to be coreacted at room temperature with glycoluril
to provide a cured thermoset paint film. The curing copolymerizes
ethylenically unsaturated monomers, including functional monomers,
but excluding amine monomers, in an aqueous polymerization medium,
followed by ion exchange of the resulting reactive emulsion
polymer. The glycoluril can be processed through an ion exchange
step separately or in conjunction with the reactive emulsion
polymer. Into the latex paint of U.S. Pat. No. 4,789,694 or onto
painted surface of U.S. Pat. No. 4,789,694, in one embodiment of
the invention, the color enhancing mixtures described herein are
applied.
[0149] U.S. Pat. No. 4,613,633 (the entire contents of which are
incorporated herein by reference) describes a copolymer latex
having heterogeneous polymer particles which is particularly
suitable for paper coating, and to a paper coating composition
comprising this latex which gives coated paper having improved
adaptability to blister packaging and printing. Into the latex
paint of U.S. Pat. No. 4,613,633 or onto painted surface of U.S.
Pat. No. 4,613,633, in one embodiment of the invention, the color
enhancing mixtures described herein are applied.
[0150] U.S. Pat. No. 7,682,435 (the entire contents of which are
incorporated herein by reference) describes an oil-based pigmented
ink composition containing at least a pigment, a polymer compound
and an organic solvent, which contains, as the organic solvent,
methoxybutyl acetate in an amount of 20 to 90% by weight based on
the entire ink composition; and particularly to the above oil-based
pigmented ink composition, which contains, as the other organic
solvent, a nitrogen-containing and/or oxygen-containing
heterocyclic compound in an amount of 1 to 50% by weight based on
the entire ink composition and/or a (poly)alkylene glycol
derivative in an amount of 1 to 50% by weight based on the entire
ink composition; and to the above oil-based pigmented ink
composition, which has a flash point of 61.degree. C. or higher, a
viscosity of 2.0 to 6.5 cp at 25.degree. C., and a surface tension
of 20 to 40 mN/m at 25.degree. C. Into the oil based pigmented ink
of U.S. Pat. No. 7,682,435 or onto painted surface of U.S. Pat. No.
7,682,435, in one embodiment of the invention, the color enhancing
mixtures described herein are applied.
[0151] U.S. Pat. Application Publ. No. 20090088500 (the entire
contents of which are incorporated herein by reference) describes
an oil-based ink composition having a colorant, an organic solvent
and a polymeric compound, and optionally an alkylamine ethylene
oxide derivative as a pH adjusting agent, in which the pH of an
aqueous phase is from 5.5 to 10, when ions in the ink composition
are transferred to water. This oil-based ink composition prevents
corrosion of a nozzle plate and is improved in storage stability,
and thus can ensure printer reliability such as ink-jet stability
obtainable even after long storage thereof, and can withstand
outdoor service environments. Into the oil-based ink composition of
U.S. Pat. Application Publ. No. 20090088500, in one embodiment of
the invention, the color enhancing mixtures described herein are
applied.
[0152] In general, the color enhancing mixtures described herein
are applicable to other paints or inks to enhance the color
perceived by an observer.
[0153] Human eyes are not instruments which measure precise
wavelengths of light. Instead, a human eye looks for three
different ranges of wavelengths. Within the retina of the human
eye, there are specialized cells that only detect light of certain
wavelengths. Some of these cells detect reddish light, others
detect greenish light, and still others detect bluish light. These
three types of color sensitive cells are called cone cells. Cone
cells are most abundant in the fovea--the region of high visual
acuity near the center of the retina. Retinal cells are more
light-sensitive than cone cells but can not distinguish color. Rod
cells sense light and dark. It might seem as through these three
types of color sensors will only allow one to see three colors.
Yet, a wide variety of colors are perceived when two or more of the
color sensors are stimulated at once. Each sensor informs the brain
about how much light it sees and the brain interprets the mixture
of responses as a particular color.
[0154] In general, visible light of a particular wavelength
stimulates all three types of cone cells to some extent. However,
the cells do not respond equally to each wavelength of light. When
exposed 680 nm (680 nanometer) light, the cone cells specialized
for reddish light respond much more strongly than those specialized
for greenish or bluish light. Because of this strong response by
the red sensors, the light appears to be red. Yellow light at 580
nm is in between red and green light. Both the red sensitive cone
cells and the green sensitive cone cells respond moderately when
exposed to yellow light. The brain interprets this balanced
response as yellow light.
[0155] But the same response can be invoked from your retina by
exposing it to an equal mixture of pure red and green lights.
Again, both the red sensitive and green sensitive cone cells
respond moderately, and it appears to the brain as yellow light,
rven though there is no pure yellow light at 580 nm reaching your
retina. Likewise, a mixture of pure red, green, and blue lights can
make one see virtually any color. The only problem comes in
choosing the pure red, green, and blue wavelengths. This is the
technique used by a television. It creates relatively pure red,
green, and blue lights with phosphor dots and "tricks" the eyes
into seeing any color across the visible spectrum.
[0156] Accordingly, in a red paint, this paint absorbs light that
would stimulate green or blue sensors of your eyes. All that is
left is reflected light that stimulates red sensors, so the eye
perceives the paint as red. Most paint pigments are based on
specific molecules that absorb light in a particular range of
wavelengths. Many metal compounds, including those of copper,
chromium, iron, antimony, nickel, and lead absorb certain
wavelengths of light and appear brightly colored. If one starts
with white light and removes various amounts of the three primary
colors of light, one can create any color of paint. If you remove
all light, the paint appears to be black. A yellow pigment absorbs
some blue light, and a cyan pigment absorbs some red light. What is
left is mostly green light. The more of each primary pigment added
to the paint, the more completely the paint will absorb its color
of light, and the deeper the color the paint will become.
[0157] Inks are similar to paints except that inks contain
dissolved dyes rather than solid pigment particles. Inks do not
contain any reflective white pigments. Inks themselves tend to be
transparent but colored. Inks rely on the underlying paper to
reflect light. Paper consists mainly of cellulose, a clear natural
polymer. Because this cellulose is finely divided in paper, it
reflects light at each surface and the paper appears white. Often
white paint pigments are applied to paper during manufacture to
make the paper even whiter.
[0158] In one aspect of the invention, the conventional dynamic of
the absorption of light in a paint normally resulting only in the
heating of the paint is changed to a dynamic of the absorbed light
(normally lost from the absorption) being emitted a color of light
of intended paint color. Thus, the brightness of the paint or ink
or coating is enhanced over that which would normally be lost to
absorption. Furthermore, "color shifting" from bands of light
outside the visible in the ultraviolet or infrared which normally
contribute nothing to the perceived light reflected to the eye
provides an additional source of color enhancement.
[0159] Conventionally, in the production of the fluorescent ink,
fluorescent pigments were employed in place of organic or inorganic
color pigments exhibiting absorption in a visible light region and
being used in the ordinary printing inks. In order to identify
fluorescent images formed on an image-printed article, it is
required to irradiate the image-printed article with ultraviolet
rays employed as an exciting light. When the image-printed article
was irradiated with ultraviolet rays, the ultraviolet rays are
absorbed by the fluorescent substance of fluorescent images,
thereby causing the emission of fluorescence in the visible region.
This fluorescence was recognized through visual observation or
using a camera, and represents a limited demonstration of the
concept utilized and yet extended by the present invention. In one
aspect of the invention here, a mixture of down-converting
particles tuned to a specific excitation and emission are used
instead of a fixed fluorescent particle. In one aspect of the
invention here, a mixture of down-converting particles tuned to a
specific excitation and emission are used instead of or in
complement to the mixture of down-converting particles.
[0160] As described in U.S. Pat. No. 6,744,960 (the entire contents
of which are incorporated herein by reference) and applicable to
this invention, pump radiation may comprise natural light, i.e.,
sunlight, or artificial light such as from UV or blue light
emitting diodes (LED) or fluorescent lights. The light incident on
the fluorescent structure need only comprise radiation having
wavelengths within the absorption spectrum of the quantum dots.
Since the absorption spectrum of the quantum dots comprises
wavelengths shorter than the wavelength of emission from the
quantum dots, the pump radiation includes wavelengths shorter than
the emitted wavelengths. For example, sunlight can be employed to
pump a fluorescent structure 10 having a layer of quantum dots
comprising CdSe particles 5.0 nm in diameter, which emit at an
optical wavelength of 625 nm, since the sun radiates light across a
broad spectrum including light having wavelengths at least 50 nm
shorter than 625 nm. Alternatively, such a fluorescent structure
can be pumped with one or more light emitting diodes (LEDs) that
provide light of, for example, 550 nm. Incandescent lights as well
as ultraviolet light sources such as UV LEDs would also be capable
of exciting the layer of quantum dots.
[0161] The fluorescent structures described in U.S. Pat. No.
6,744,960 and applicable to this invention can be employed in
various applications requiring bright, narrowband illumination. For
example, light sources of colored illumination are useful in
constructing signs, in creating artistic or architectural designs,
and in producing bright regions of color, including outlines, bands
and borders on products including but not limited to furniture,
automobiles, appliances, electronics, clothes or any other object
where bright color is useful for aesthetic or functional purposes.
These fluorescent structures are advantageously capable of
producing intense colored light illumination during daytime when
exposed to daylight. Since, quantum dots do not degrade with
exposure to UV rays such as produced by the sun, the structure has
a long lifetime and can be incorporated in architectural features,
such as a border to highlight a rooftop of a building during the
daytime.
[0162] Yet, unlike that in U.S. Pat. No. 6,744,960, in this
invention, upconverting particles stimulated by IR light from
natural or artificial sources complement the fluorescence and yield
even brighter structures. Moreover, mixtures of the down converters
permit a wider spectrum of the "out-of-band" color region from the
natural or artificial radiation source to be utilized and tuned for
example to a specific color emission or to a mixture of primary
color emissions.
[0163] In still another embodiment of the invention, there is
provided a light emitting composition including first color
emitters configured to emit, upon exposure to an energy source,
visible light at a target color in response to absorption of energy
at a first band of wavelengths and second color emitters configured
to emit, upon exposure to the energy source, visible light offset
from the target color in response to absorption of energy at the
first band of wavelengths, Light intensity observable at the target
color is enhanced relative to reflected white light without
emission from the first and second color emitters. Further, by
offsetting the emissions about the target color, the resulting
color would appear to the human eye to be richer in color. The
offset can be an offset of 5, 10, 15, 20, 25, and 30 nm or more.
The offset can be a positive or negative offset from the target
color. More specifically, a color purity or chromaticity can be
changed by the offset defined above.
[0164] In another embodiment, the offset values can produce a
saturation quality where the target color will appear different
under different lighting conditions. For instance, a room painted
to a specific target color by the mixtures of different color
emitters will appear different at night (under artificial lighting
conditions) than in daylight. The offset can be an offset of 50,
100, 150, 200, 250, and 300 nm or more. The offset can be a
positive or negative offset from the target color.
[0165] Moreover, a target color can vary from its original color by
adding white pigment to make a lighter version or by adding black
pigment to make a darker version.
[0166] Table 1 included below includes the recognized wavelength
intervals for the major visible color bands.
TABLE-US-00001 TABLE 1 color wavelength interval red ~700-635 nm
orange ~635-590 nm yellow ~590-560 nm green ~560-490 nm blue
~490-450 nm violet ~450-400 nm
[0167] One area of particular application for the color shifting
particle mixtures would be their use as coatings on glass beads for
use in retro-reflective paints. FIG. 7 shows a schematic
representation of the retro-reflective paint geometry. The glass
bead serves as an optical element directing incident light along a
path of reflection back to the observer that is nearly, if not
perfectly, aligned with the incident ray. Instead of diffuse
scatter, the light is directed back and appears brighter than
"normal." In this invention, the color shifting particle mixtures
would be applied to the paint binder or, as shown in FIG. 7 as a
color converter layer on the glass bead so that light (not of the
color of the painted surface) would be converted to that color of
the painted surface (or of a combination of primary color emissions
simulating the color of the painted surface) so that additional
light enhancement is realizable.
[0168] In conventional retroreflective road paint applications,
there exist two classes of retroreflective beads: IGB-I and IGB-II.
IGB-I is used to be mixed with the paint prior to stripping the
road. As the paint layers wear, the beads are exposed giving the
enhanced visibility of road markings IGB-II is used to be dropped
on the freshly stripped paint surface on the road to give immediate
enhanced visibility to night drivers. Table 2 (reproduced below
from http://www.indoglassbeads.com/road-marking-glass-beading.htm)
provides recognized specifications for these materials.
TABLE-US-00002 TABLE 2 Chemical & Physical Properties Basic
material SiO2 69-71% Shape Spherical Color Clear Specify gravity
g/cm3 2.5 Hardness (Moh's) 6.0 Refractive Index 1.5-1.55 Type Sieve
Size um Retained by % IGB-I 1180 0-3 (Intermix) 850 5-20 425 65-95
<425 0-10 Roundness >70% IGB-II 850 0-5 (Drop On) 600 5-20
300 30-75 180 10-30 <180 0-15 Roundness >80%
[0169] U.S. Pat. No. 5,650,213 (the entire contents of which are
incorporated herein by reference) describe retroreflective
compositions having a non-volatile matrix material, a volatile
constituent, and a plurality of retroreflective microsphere beads
where the ratio of the volume of matrix material to the volume of
retroreflective microsphere beads is in the range of 75% to 185%.
The retroreflective microsphere beads in U.S. Pat. No. 5,650,213
had a diameter of 20 to 200 microns, were constructed of glass, and
had an index of refraction ranging from 1.7 to 2.5. These and other
retroreflective compositions include (in one embodiment of the
invention), the color enhancing mixtures of the invention coated
thereon or in the paint composition itself.
[0170] Accordingly, in this invention, a glass bead in for example
a blue paint would have down converters and up converters in the
color converter layer on the glass bead so that white light (for
example as from a head light on a car) would have its UV and IR
light converted more to blue light thereby producing more blue
light to be reflected from the blue painted surface. Alternatively,
for a green painted surface, white light would have its UV and IR
light converted more to green thereby producing more green light to
be reflected from the glass bead in the painted surface.
[0171] FIG. 8 shows a schematic representation of a painted surface
in which a color shifting layer in disposed as a topcoat. Similar
to above before, a blue paint would have down converters and up
converters in the color converter layer applied at a topcoat so
that white light (for example as from a head light on a car) would
have its UV and IR light converted more to blue light thereby
producing more blue light to be reflected from the blue painted
surface. Alternatively, for a green painted surface, white light
would have its UV and IR light converted more to green light
thereby producing more green light to be reflected from the glass
bead in the painted surface.
[0172] In another embodiment, the colors in the visible part of the
spectrum are also color shifted. A blue paint would have down
converters and up converters in the color converter layer applied
at a topcoat so that white light (for example as from a head light
on a car) would have its deep blue and red-green light converted
more to blue light thereby producing more blue light to be
reflected from the blue painted surface. Alternatively, for a green
painted surface, white light would have its blue and red light
converted more to green light thereby producing more green light to
be reflected from the glass bead in the painted surface.
[0173] Stated differently, with the color shifting particles of the
invention in the color converter layer, the red paint or ink has
color shifting particles which down convert the spectrum of light
of a higher energy than red (e.g., a blue light) and up convert the
spectrum of light of a lower energy than red (e.g., near IR and IR
light). Similarly, the green paint or ink has color shifting
particles which down convert the spectrum of light of a higher
energy than green (e.g., a blue light) and up convert the spectrum
of light of a lower energy than green (e.g., red, near IR, and IR
light). Similarly, the blue paint or ink has color shifting
particles which down convert the spectrum of light of a higher
energy than blue (e.g., a UV light) and up convert the spectrum of
light of a lower energy than blue (e.g., green, red, near IR, and
IR light).
[0174] Cosmetic products: Cosmetics are substances used to enhance
the appearance or odor of the human body. Cosmetics include but are
not limited to skin-care creams, lotions, powders, perfumes,
lipsticks, fingernail and toe nail polish, eye and facial makeup,
permanent waves, colored contact lenses, hair colors, hair sprays
and gels, deodorants, baby products, bath oils, bubble baths, bath
salts, butters and many other types of products. A subset of
cosmetics is called "make-up," which refers primarily to colored
products intended to alter the user's appearance. Many
manufacturers distinguish between decorative cosmetics and care
cosmetics.
[0175] In one aspect of the invention, the color mixtures described
above are included in those cosmetics that are intended to alter
the user's appearance. In one aspect of the invention, the color
mixtures described above are included in those cosmetics that are
used to protect the body from the harmful UV aging effects.
[0176] Accordingly, those products where the color mixtures
described above would be suitable for inclusion include but are not
limited to lipstick, lip gloss, lip liner, lip plumper, lip balm,
lip conditioner, lip primer, and lip boosters. Those products
further include foundation, used to smooth out the face and cover
spots or uneven skin coloration, usually a liquid, cream, or
powder. Those products further include powders, used to give a
matte finish, and also to conceal small flaws or blemishes. Those
products further include rouge, blush or blusher, cheek coloring
used to bring out the color in the cheeks and make the cheekbones
appear more defined. Those products further include bronzers, used
to give skin a bit of color by adding a golden or bronze glow.
Those products further include mascara used to darken, lengthen,
and thicken the eyelashes (available in natural colors such as
brown and black, but also comes in bolder colors such as blue,
pink, or purple). Those products further include eye liners, eye
shadows, eye shimmers, and glitter eye pencils as well as different
color pencils used to color and emphasize the eyelids, eyebrow
pencils, creams, waxes, gels and powders used to color and define
the brows. Those products further include nail polish, used to
color the fingernails and toenails. Those products further include
concealers and makeup used to cover any imperfections of the
skin.
[0177] Also included in the general category of cosmetics are skin
care products. These include creams and lotions to moisturize the
face and body, sunscreens to protect the skin from damaging UV
radiation, and treatment products to repair or hide skin
imperfections (acne, wrinkles, dark circles under eyes, etc.).
Cosmetics can be liquid or cream emulsions; powders, both pressed
and loose; dispersions; and anhydrous creams or sticks.
[0178] In this application area, the color mixtures of the
invention can both provide color shifting capability (as detailed
above), but can also moderate UV light damage to skin or hair
exposed to UV light irradiation. The cosmetics in this way can
additionally or optionally provide a protective coating which has a
mixture of light scattering and light emitting particles
configured, upon exposure to UV light, to convert a first part of
the UV light into visible light, emit from the mixture a fraction
of the visible light, and reflect from the mixture a second part of
the UV light such that the second part of the UV light is not
absorbed by the skin or hair.
[0179] For example, while not limited to the details described
below, UV light from the sun incident on the protective coating
could have 50% or more of the UV light reflected due to the index
of refraction change between air and the protective coating. That
part of the UV light entering the interior layers of the protective
coating converted into visible light. Other parts of the UV light
would be scattered from protective coating and not incident on the
underlying surface.
[0180] Regardless, the color shifting mixtures of the invention can
include a cosmetically acceptable medium compatible with all skin,
lip, or hair materials with which it comes into contact with. When
these composition are to be applied in the form of an emulsion, the
composition may optionally additionally include a surfactant,
preferably in a quantity of 0 to 30% by weight, preferably from
0.01 to 30% by weight based on the total weight of the composition.
The emulsion may be a single or multiple emulsion. The color
shifting mixtures of the invention may be present in any one or
more of these phases.
[0181] According to the application envisaged, the composition may
also additionally include at least one film-forming polymer, in
particular for mascaras, eyeliner or hair compositions of the
lacquer type. The polymer may be dissolved or dispersed in a
cosmetically acceptable medium and possibly associated with at
least one coalescing agent and/or at least one plasticizer. The
composition according to the invention may also include a fat phase
that contains in particular at least one liquid fat and/or at least
one fat that is solid at ambient temperature and atmospheric
pressure. Liquid fats, often called oils, may constitute 0 to 90%,
preferably 0.01 to 85% by weight based on the total weight of the
fat phase. Solid or pasty fats may be chosen in particular from
waxes, gums and mixtures thereof. The composition may contain 0 to
50%, preferably 0.01 to 40%, and in particular 0.1 to 30% by weight
of solid or pasty fats based on the total weight of the
composition.
[0182] The composition according to the invention may additionally
include 0 to 30%, preferably 0.01 to 35% by weight of other
particles based on the total weight of the composition. These
particles may in particular be a pigment other than the color
mixtures of the invention, a pearl pigment or a filler. The
presence of these other particles makes it possible in particular
to make the composition opaque.
[0183] In addition, the composition according to the invention may
include ingredients conventionally present in such compositions,
such as preservatives, antioxidants, thickeners, perfumes,
moisturizing agents, sun filters, essential oils, vegetable
extracts and vitamins.
[0184] In one embodiment of the invention, the color shifting
mixtures of the invention can be used in shampoos, conditioners,
gels, styling compounds, sprays, and other beauty products. In one
embodiment of the invention, he color shifting mixtures of the
invention are added to these hair and beauty products to increase
the sheen of one's hair for example. The sheen in one's hair is a
property of the surface finish of the hair and the scattering of
the light at the top surfaces. Standard hair treatments "repair"
i.e., fill the surfaces torn in the hair by aging, excessive
washing, etc. In this embodiment of the invention the color
converters in the hair treatments also fill into the broken
surfaces. The effect would be to provide a surface of the hair
which reflects more visible light and also has less diffusive
scatter, by the filing and smoothing of the surfaces.
[0185] The color shifting mixtures of the invention can include (in
addition to the up converters and down converters described herein)
a number of other emulsions and conditioning agents such as
described in U.S. Pat. Appl. No. 2005/0136258, U.S. Pat. Appl. No.
2005/0265935, U.S. Pat. Appl. No. 2006/0083762, U.S. Pat. Appl. No.
2006/0165621, U.S. Pat. Appl. No. 2007/0274938, and U.S. Pat. No.
7,608,237, the entire contents of each of these patent documents
are incorporated herein by reference.
[0186] DISPLAYS: In a conventional electronic ink display, i.e. an
electrophoretic display, titanium dioxide particles approximately
one micrometer in diameter are dispersed in a hydrocarbon oil. A
dark-colored dye is also added to the oil, along with surfactants
and charging agents that cause the particles to take on an electric
charge. This mixture is placed between two parallel, conductive
plates are typically separated by a gap of 10 to 100 .mu.m. Upon
applying a voltage the two plates, the particles will migrate
electrophoretically to the plate bearing the opposite charge from
that on the particles. When the particles are located at the front
(viewing) side of the display, it appears white, because light is
scattered back to the viewer by the high-index "white" titanium
dioxide particles. When the particles are located at the rear side
of the display, the display appears dark, because the incident
light is absorbed by the colored dye. If the rear electrode is
divided into a number of small picture elements (pixels), then an
image can be formed by applying the appropriate voltage to each
region of the display to create a pattern of reflecting and
absorbing regions.
[0187] U.S. Pat. Appl. Publ. No. 20040257330 (the entire contents
of which are incorporated herein by reference) describes details of
formation of a conventional electronic ink display that would be
applicable to the base components depicted in the displays of this
invention. U.S. Pat. Appl. Publ. No. 20040257330 describes for
example that it is possible to use a liquid filling the pixel
cells, which is high insulative and colorless and transparent,
including: aromatic hydrocarbons, such as toluene, xylene,
ethylbenzene and dodecylbenzene; aliphatic hydrocarbons, such as
hexane, cyclohexane, kerosine, normal paraffin and isoparaffin;
halogenated hydrocarbons, such as chloroform, dichloromethane,
pentachloromethane, tetrachloroethylene, trifluoroethylene and
tetrafluoroethylene, various natural or synthetic oils, etc. These
may be used singly or in mixture of two or more species.
[0188] A dispersion liquid can be used which may be colored with
oil soluble dye having a color of R (red), G (green), B (blue), C
(cyan), M (magenta), Y (yellow), etc. Examples of the dye may
preferably include azo dyes, anthraquinone dyes, quinoline dyes,
nitro dyes, nitroso dyes, penoline dyes, phthalocyanine dyes, metal
complex salt dyes, naphthol dyes, benzoquinone dyes, cyanine dyes,
indigo dyes, quinoimine dyes, etc. These may be used in
combination. Examples of the oil soluble dye may include Vari Fast
Yellow (1101, 1105, 3108, 4120), Oil Yellow (105, 107, 129, 3G,
GGS), Vari Fast Red (1306, 1355, 2303, 3304, 3306, 3320), Oil Pink
312, Oil Scarlet 308, Oil Violet 730, Vari Fast Blue (1501, 1603,
1605, 1607, 2606, 2610, 3405). Oil Blue (2N, BOS, 613), Macrolex
Blue RR, Sumiplast Gren G, Oil Green (502, BG), etc. A
concentration of these dyes may preferably be 0.1-3.5 wt. %.
[0189] At the particle surface of the electrophoretic particles in
the pixels, at least an amphipathic residual group derived from a
reactive surfactant is fixed. Particles used for reaction may
include organic or inorganic particles, pigment particles coated
with a polymer, and polymer particles coated with a dye. An average
particle size of these particles may be 10 nm to 5 .mu.m,
preferably 15 nm to 2 .mu.m.
[0190] Examples of organic pigments which can be used in the pixel
cells include azo pigments, phthalocyanine pigments, quinacridone
pigments, isoindolinone pigments isoindolin pigments, dioazine
pigments, perylene pigments, perinone pigments, thioindigo
pigments, quinophthalone pigments, anthraquinone pigments, nitro
pigments, and nitroso pigments. Specific examples thereof may
include: rod pigments, such as Quinacridone Red, Lake Red,
Brilliant Carmine, Perylene Red, Permanent Red, Toluidine Red and
Madder Lake; green pigments, such as Diamond Green Lake,
Phthalocyanine Green, and Pigment Green; blue pigments, such as
Victoria Blue Lake, Phthalocyanine Blue, and Fast Sky Blue; yellow
pigments, such as Hansa Yellow, Fast Yellow, Disazo Yellow,
Isoindolinone Yellow, an Quinophthalone Yellow; and black pigments,
such as Aniline Block and Diamond Black.
[0191] Examples of the inorganic pigments which can be used in the
pixel cells include: white pigments, such as titanium oxide,
aluminum oxide, zinc oxide, lead oxide, and zinc sulfide; black
pigments, such as carbon black, manganese ferrite block, cobalt
ferrite black, and titanium black; red pigments, such as cadmium
red, red iron oxide, and molybdenum red; green pigments, such as
chromium oxide, viridian, titanium cobalt green, cobalt green, and
victoria green; blue pigments, such as ultramarine blue, prussian
blue, and cobalt blue; and yellow pigments, such as cadmium yellow,
titanium yellow, yellow iron oxide, chrome yellow, and antimony
yellow.
[0192] As the pigment particles coated with a polymer, it is
possible to use particles of the above described pigments coated
with a polymer, such as polystyrene, polyethylene,
polymethylacrylate, and polymethylmethacrylate. Coating of the
pigment particles with the polymer may be performed by using a
known method such as a polymer precipitation method or suspension
polymerization.
[0193] As the polymer particles colored with a dye, it is possible
to use particles of preliminarily synthesized crosslinkable polymer
fine particles colored with a dye, particles obtained through
suspension polymerization or emulsion polymerization of a
polymerizable monomer containing a dye, etc.
[0194] In the electrophoretic particles to which surface at least
the reactive surfactant-derived amphipathic residual group can be
fixed, when the reactive surfactant is adsorbed by the particle
surface and co-polymerized, a comonomer to be co-polymerized with
the reactive surfactant is solubilized in the adsorption layer and
polymerized or co-polymerized with the use of a polymerization
initiator. As a result, the reactive surfactant-derived amphipathic
residual group can be fixed at the particle surface.
[0195] Specific formulation procedures described in U.S. Pat. Appl.
Publ. No. 20040257330 are suitable for this invention. Accordingly,
in this invention, white electrophoretic particles and a dispersion
medium colored with a blue dye can be filled in a pixel cell. The
electrophoretic particles can be positively charged by fixing an
amphipathic residual group derived from a reactive surfactant
having a cationic functional group. When an electric field
[0196] E is applied to the electrophoretic liquid, the positively
charged electrophoretic particles are moved toward the upper side
of the cell and distributed over the upper display surface. As a
result, when the cell is observed from above, the cell looks white
due to distribution of the white electrophoretic display. On the
other hand, when the electric field E is applied to the
electrophoretic liquid in an opposite direction, white
electrophoretic particles are moved toward the bottom of the cell
and distributed thereover, so that the cell looks blue when
observed from above.
[0197] Accordingly, in this invention, a colorless dispersion
medium and two types (white and black) of electrophoretic particles
can be included in a pixel cell. The white electrophoretic
particles are positively charged by fixing an amphipathic residual
group derived from a reactive surfactant having a cationic
functional group, and the black electrophoretic particles are
negatively charged by fixing an amphipathic residual group derived
from an anionic functional group. When an electric field E is
applied to the electrophoretic liquid, the positively charged white
electrophoretic particles are moved toward the upper side of the
cell and the negatively charged black electrophoretic particles 1 e
are moved toward the lower (bottom) side of the cell. As a result,
when the cell is observed from above, the cell looks white due to
distribution of the white electrophoretic display. On the other
hand, when the electric field E is applied to the electrophoretic
liquid in the opposite direction, the black electrophoretic
particles are moved toward the upper side of the cell, and the
white electrophoretic particles are moved toward the bottom of the
cell, so that the cell looks black when observed from above.
[0198] U.S. Pat. Appl. Publ. No. 20040257330 describes for example
a surfactant synthesis example where 4.8 g (41 mmol) of
chlorosulfuric acid was gradually added dropwise to 35 ml of
pyridine cooled at 0.degree. C., followed by stirring for 30
minutes. To the reactive mixture, 9 ml of a pyridine solution
containing 7.0 g (41 mmol) of 10-undecene alcohol was gradually
added dropwise, followed by stirring for 1 hour at 0.degree. C. and
further stirring for 20 hours at 55.degree. C. The reaction mixture
was poured into a saturated sodium hydrogen-carbonate aqueous
solution cooled at 0.degree. C., and stirred for 1 hour and further
stirred of 20 hours at room temperature. After the reaction, the
solvent of the reaction mixture was distilled off under reduced
pressure. To the residue, acetone was added to precipitate a
crystal. The crystal was dissolved in methanol and thereafter, a
methanol insoluble content was removed, followed by removal of the
solvent under reduced pressure to obtain a crystal. The crystal was
recrystallized from a mixture solvent (methanol/acetone=1/3) to
obtain a reactive surfactant having an anionic functional group
represented by the following formula (Yield: 80%).
CH2=CH--(CH2)9-OSO3Na
As a result of 1H-NMR (400 MHz, CD3, OD) of the resultant reactive
surfactant, measured values (.delta./ppm) including 1.33 (12H),
1.68 (2H), 2.02 (2H), 4.00 (2H), 4.95 (2H) and 5.83 (1H) were
obtained, thus identifying synthesis of the objective reactive
surfactant (33).
[0199] U.S. Pat. Appl. Publ. No. 20040257330 describes thereafter
the process for making a pixel solution, 5 wt. parts of titanium
oxide and 3 wt. parts of the reactive surfactant prepared in the
synthesis example above were added in 100 wt. parts of water,
followed by irradiation of ultrasonic wave to form a bimolecular
adsorption layer of the reactive surfactant at the surface of
titanium oxide particles.
[0200] To the above treated particles, 2 wt. parts of di-n-butyl
fumarate and 0.05 wt. part of potassium persulfate were added,
followed by polymerization reaction for 48 hours at 60.degree. C.
in a nitrogen atmosphere. After coarse particles contained in the
reaction mixture were removed with a filter, objective particles
contained in the removed with a filter, objective particles
contained in the reaction mixture were separated by centrifugation.
The resultant precipitate was repeatedly recovered by filtration
and washed, followed by drying to obtain particles to which the
reactive surfactant-derived amphipathic residual group was fixed at
the particle surface.
[0201] The obtained particles were subjected to salt exchange
reaction by using a methanol solution o of
n-hexadecyltrimethylammonium hydride (C16H33(CH3)3NOH), followed by
washing of excessive ions with acetonitrile to obtain objective
electrophoretic particles.
[0202] An electrophoretic liquid was prepared by dispersing 5 wt.
parts of the electrophoretic particlesin 50 wt. parts of
isoparaffin ("Isopar H", mfd. by Exxon Corp.) colored blue by the
addition of 0.1 wt. part of a dye ("Oil Blue N", mfd. by Aldrich
Corp.). The prepared electrophoretic liquid was filled and sealed
in a plurality of cells
[0203] In this invention, the particles in U.S. Pat. Appl. Publ.
No. 20040257330 (e.g., the titanium oxide) would be replaced with a
mixture of color emitting particles or larger microscopic particle
of the titanium oxide would be coated with nano-meter size mixtures
of the color emitters of the invention.
[0204] FIG. 9A shows one example of an electronic ink display where
a white color converting layer is applied for example to dielectric
(e.g., titanium dioxide) particles. Here, depending on the voltage
state of a pixel, the "white particles" in the black or dark dye
are either drawn up to the near surface of the top electrode where
white light is reflected or are repelled face he top electrode
where the black dye, not at the near surface of the top electrode,
absorbs incident light. The contrast then depends on the amount of
light reflected from the "white particles" as opposed to the light
not reflected from the blue dye. Here, in this embodiment, the
dielectric particles include the color shifting particles of this
invention to produce more white light by up converting of the
infrared part of the spectrum and down converting of the UV part of
the spectrum.
[0205] Upon reversing the charge on the top electrode, the
dielectric particles is attracted to the bottom electrode, and
little if any light is reflected. Thus, the voltage state of each
pixel thus determines whether that pixel appears white or black to
the observer on the top side.
[0206] The excitation light for the display shown in FIG. 9 may be
an ultraviolet light source or a black body or solar source (having
wavelengths in the ultraviolet), in accordance with various
embodiments of the invention. If the excitation light is
ultraviolet light, then when the light emitting material emits
visible light in response to the ultraviolet light, a
down-conversion physical phenomenon occurs. Specifically,
ultraviolet light has a shorter wavelength and higher energy than
visible light. Accordingly, when the light emitting material
absorbs the ultraviolet light and emits lower energy visible light,
the ultraviolet light is down-converted to visible light because
the ultraviolet light's energy level decreases when it is converted
into visible light. In embodiments, the light emitting material is
fluorescent material.
[0207] The excitation light for the display shown in FIG. 9 may be
infrared light source or a black body or solar source (having
wavelengths in the infrared), in accordance with various
embodiments of the invention. If the excitation light is infrared
light, then when the light emitting material emits visible light in
response to the infrared light, an up-conversion physical
phenomenon occurs. Specifically, infrared light has a longer
wavelength and lower energy than visible light. Accordingly, when
the light emitting material absorbs the infrared light and emits
higher energy visible light, the infrared light is up-converted to
visible light because the infrared light's energy level increases
when it is converted into visible light. Accordingly, in
down-conversion embodiments, when ultraviolet light is absorbed by
light emitting particles on the blue dye, visible light is emitted
from the light emitting particles. Likewise, in up-conversion
embodiments, when infrared light is absorbed by light emitting
particles, visible light is emitted from the light emitting
particles.
[0208] The size of the particles in the white light converting
layer may be smaller than the wavelength of visible light, which
may reduce or eliminate visible light scattering by the particles.
Examples of particles that are smaller than the wavelength of
visible light are nanoparticles or molecules. According to these
embodiments, each of the light emitting particles could have a
diameter that is less than about 500 nanometers. According to these
embodiments, each of the light emitting particles could have a
diameter that is less than about 400 nanometers. According to
embodiments, each of the light emitting particles could have s a
diameter that is less than about 300 nanometers. According to these
embodiments, each of the light emitting particles could have a
diameter that is less than about 200 nanometers. According to these
embodiments, each of the light emitting particles could have a
diameter that is less than about 100 nanometers. The light emitting
particles may be individual molecules.
[0209] Different types of light emitting particles may be used
together that have different physical characteristics. For example,
in order to emit color images from selected pixels of the display
of FIG. 9B, for example, different types of dyes may be utilized in
pixels associated with different colors. FIG. 9B shows three pixels
including respectively, red, green and blue dyes. When the top
electrode attracts the dielectric particles with the white color
enhancing layers to the top surface, the dye molecules in those
pixels are displaced, turning that particular pixel the color of
the dye. In one embodiment of the invention, the dyes (similar to
the inks described below) contain nanoparticles of the
color-shifting mixtures.
[0210] For example, a first type of light emitting particles may be
associated with the color red, a second type of light emitting
particles may be associated with the color green, and a third type
of light emitting particles may be associated with the color blue.
Although the example first type, second type, and third type of
light emitting particles are primary colors, other combinations of
colors (e.g. types of colors and number of colors) can be used to
facilitate a color display.
[0211] FIG. 9C shows another embodiment in which three pixels
include respectively, red, green and blue dyes where the dyes
themselves have contain the color-shifting (and thus color
enhancing) mixtures. When the top electrode attracts the dielectric
particles with the white color enhancing layers to the top surface,
the dye molecules in those pixels are displaced, turning that
particular pixel the color of the color-enhanced dye. In one
embodiment of the invention, the dyes (similar to the inks
described below) contain nanoparticles of the color-shifting
mixtures.
[0212] FIG. 9D shows another embodiment in which three pixels
include dielectric particles with respectively, red, green and blue
color enhancing layers. When the top electrode attracts the
dielectric particles with the distinct color enhancing layers to
the top surface, the dye molecules in those pixels are displaced,
turning that particular pixel the color of the dielectric
particle's converting layer.
[0213] FIG. 10A shows one example of an IR light activated display
of the invention. Accordingly, in this embodiment, a display can be
produced utilizing color shifting particles of different
upconversion color emission characteristics segregated into
different display pixels.
[0214] In this embodiment, an IR laser illuminates a near surface
of a pixilated surface having the color shifting particles
attracted thereto (by selectively biasing separate pixels). In one
embodiment, IR light is emitted so as to undergo total internal
reflection along the interior surface of the IR light channel
plate. For the IR light channel plate, typically crystalline
materials are transparent in the of 980 nm (NIR) light range;
quartz, glass, Y.sub.2O.sub.3, etc. Also, small polymers
(length/molecular weight) can also be transmissive but transmission
in the range of IR is dependent on type and length etc.
[0215] In one embodiment, the IR light channel plate contains
within itself scattering centers which scatter light off axis so as
to illuminate a portion of the pixel region close to the IR light
channel plate. In the example shown in FIG. 10, an IR light channel
provides IR light propagation across the pixilated surface. The IR
light in this example only stimulates the blue color converting
layer, as the bias electrode above the blue pixel has attracted the
blue color converting layer (e.g., with negative particles) to the
near surface, while the red and green color converting layers are
repelled.
[0216] Different types of light emitting particles may absorb
different ranges of excitation light to emit the different colors.
Accordingly, the wavelength range of the excitation light may be
modulated in order to control the visible color emitted from the
light emitting particles. In embodiments, different types of light
emitting particles may be mixed together and integrated into/onto a
substrate or in the dyes or inks of the pixel. By modulating the
wavelength of the excitation light, along with spatial modulation
and intensity modulation of the excitation light, visible light
with specific color characteristics can be created in substrate.
For example, by selectively exciting specific combinations of
different types of light emitting particles associated with primary
colors, virtually any visible color can be emitted.
[0217] FIG. 10B shows another example of an IR light activated
display of the invention. In this embodiment, infrared light
emitting diodes are patterned on a substrate. The pattern of diodes
are registered with a pattern of pixels. Each of the pixels
contains a specific color emitter, for example a blue color
upconverter matrix containing the color shifting mixtures of the
invention.
[0218] In one embodiment, anti-reflective coatings or filters can
be applied. For example, a reflective layer may be employed on
surface opposite the LED light sources to reflect unconverted light
back through the color shifting particle mixture. Indeed, as in
laser cavity designs, this color pass filer would reflect light of
the "wrong" unconverted wavelength back through the color shifting
particle mixture for increased conversion.
[0219] U.S. Pat. No. 6,054,724 (the entire contents of which are
incorporated herein by reference) describes ways to produce arrays
of infrared light emitting diodes. The techniques described in that
patent would be applicable for forming the patterned substrate
containing the infrared light emitting LEDs shown in FIG. 10B.
Alternatively, bonding technologies can be used to take diced laser
diodes and mount laser diodes into the red, blue, and green pixel
elements shown in FIG. 10B.
[0220] U.S. Pat. No. 6,104,740 (the entire contents of which are
incorporated herein by reference) describes ways to produce arrays
of infrared light emitting diodes and blue light emitting diodes on
the same chip. The techniques described in that patent would be
applicable for forming the patterned substrate containing the
infrared light emitting LEDs shown in FIG. 10B. In this case, some
of the light emitting LEDs would be blue light emitters, whose
light could be either directly passed through the display or itself
down converted.
[0221] FIG. 10C shows another example of an IR light activated
display of the invention.
[0222] In this embodiment, microelectrical mechanical systems
(MEMS) are patterned on a substrate. The MEMS devices contain
shutters which when open allow IR light from a back light source to
pass through holes in the substrate and illuminate respective
pixels. Each of the pixels contains a specific color emitter, for
example a blue color upconverter matrix containing the color
shifting mixtures of the invention. The IR back light source may be
a an infrared glow bar with appropriate filters or could be light
diffused from an IR LED or IR laser source.
[0223] FIG. 11 shows one example of a liquid crystal (LC) light
activated display in which the color filters have the color
shifting particles of this invention. In one embodiment of this
invention, the color shifting particles can be employed in the
color filter elements associated with conventional liquid crystal
display technology. In this embodiment, light from a back light
source passes through red, blue, and green color filters disposed
in front of respective pixels of the liquid crystal display.
Normally, light of the "wrong" color from the white back light
would be merely absorbed making no contribution to the front side
luminance of the display. With the color shifting particles of the
invention, the white light for the red filter has color shifting
particles which down convert the spectrum of light of a higher
energy than red (e.g., a blue light) and up convert the spectrum of
light of a lower energy than red (e.g., near IR and IR light).
Similarly, the white light for the green filter has color shifting
particles which down convert the spectrum of light of a higher
energy than green (e.g., a blue light) and up convert the spectrum
of light of a lower energy than green (e.g., red, near IR, and IR
light). Similarly, the white light for the blue filter has color
shifting particles which down convert the spectrum of light of a
higher energy than blue (e.g., a UV light) and up convert the
spectrum of light of a lower energy than blue (e.g., green, red,
near IR, and IR light).
[0224] Similar principles would apply to reflective LCD structures
where ambient light is passed through LC elements and reflected
from colored surfaces back through the LC elements to be viewed.
Here, the colored surfaces would have their respective reflected
light luminance increased by color shifting particles which down
convert the spectrum of light of a higher energy than red (e.g., a
blue light) and up convert the spectrum of light of a lower energy
than red (e.g., near IR and IR light) to reflect a higher luminance
of red. Similarly, the white light for the green filter has color
shifting particles which down convert the spectrum of light of a
higher energy than green (e.g., a blue light) and up convert the
spectrum of light of a lower energy than green (e.g., red, near IR,
and IR light) to reflect a higher luminance of green. Similarly,
the white light for the blue filter has color shifting particles
which down convert the spectrum of light of a higher energy than
blue (e.g., a UV light) and up convert the spectrum of light of a
lower energy than blue (e.g., green, red, near IR, and IR light) to
reflect a higher luminance of blue.
[0225] In various embodiments, reflective layers can be used at
respective color pixels, and these reflective layers can be
selective waveband reflective layers to compensate for varying
emission efficiencies of different light emitting materials. For
example, if light emitting materials that emit red light from the
red pixel emit light at a higher intensity than light emitting
materials from a blue pixel emit blue light, a selective waveband
reflective layer may compensate for these differences in emission
efficiencies. For example, a "blue" reflective layer may reflect
blue light with a higher intensity than a "red" reflective layer
reflects red light.
[0226] Aging Resistance:
[0227] Chalking, blistering, and cracking are common signs of the
aging of latex and oil based paints. UV light exposure plays a
significant role in the deterioration of paint pigments leading to
these visual discrepancies. In one embodiment of the invention, UV
light (and thus the energy contained in the UV light) is converted
and/or scattered back away from a coated or painted or stained
surface.
[0228] In this embodiment, a protective coating for moderating UV
light damage to an object exposed to UV light irradiation is
provided. The protective coating has a mixture of light scattering
and light emitting particles configured, upon exposure to UV light,
to convert a first part of the UV light into visible light, emit
from the mixture a fraction of the visible light, and reflect from
the mixture a second part of the UV light such that the second part
of the UV light is not absorbed by said object.
[0229] For example, while not limited to the details described
below, UV light from the sun incident on the protective coating
could have 50% or more of the UV light reflected due to the index
of refraction change between air and the protective coating. That
part of the UV light entering the interior layers of the protective
coating converted into visible light. Other parts of the UV light
would be scattered from protective coating and would not be
incident on the underlying surface.
[0230] Other applications: The color enhancing mixtures of the
invention described above are applicable across a broad variety of
artificially colored products. These products included (in addition
to those products listed above) the following non-exhaustive list
of products. For example, the color enhancing mixtures of the
invention described above can be included in or on the surface of
building products such as concrete products, asphalt, pavement,
bathroom and kitchen tiles, structural tiles, pavers, bricks (e.g.,
as a glazing bricks) and other glazing or glazed products.
[0231] In one illustrative example, the color contrast of tennis
court lines in day light or artificial light could be enhanced by
the color mixtures of the present invention. Moreover, depending on
the mixture additives which could include down converters targeted
to for example a primary emission line in a plasma or arc discharge
lamp, under artificial lighting (such as night-time lighting), the
tennis pavement and the lines could exhibit a significant color
change at nighttime, adding attraction to tennis as a night time
sport.
[0232] Other products where the color enhancing mixtures would have
value would be jewelry, rings, earrings, necklaces, braclets, mood
rings, candles, epoxies, contact lens, rubber products, plastic
products. Of particular example, contact lenses permit one to
change their eye color. Besides adding the color enhancing mixtures
of the invention to the typical colorants used in this product, the
colorants can be added as the retroreflective glass spheres
described above in order to produce a "cat-eyed" effect of
reflecting light from a source more directionally to an
observer.
[0233] U.S. Pat. No. 6,896,369 (the entire contents of which are
incorporated herein by reference) describes the construction of
colored contact lenses. In one embodiment of this invention, the
color enhancing mixtures of the invention (with or without a
retroreflective component) would be added to the multicolored
pattern region having an epithelial region, a pupillary margin
region, a collarette region, crypts of Fuchs elements, and a
dilator pupillae region. These regions would have a plurality of
colored elements or a combination of colored and non-colored
elements. A colored element would be a colorant sufficiently opaque
to mask the underlying region of the wearer's iris. An uncolored
element would preferably clear, but may be slightly colored by a
colorant which is sufficiently non-opaque so as not to mask the
underlying region of the wearer's iris. To the colorants of U.S.
Pat. No. 6,896,369, the color enhancing mixtures of the invention
are added.
[0234] Having generally described this invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only and are not intended to be limiting unless otherwise
specified.
[0235] Numerous modifications and variations of the invention are
possible in light of the above teachings. It is therefore to be
understood that within the scope of the appended claims, the
invention may be practiced otherwise than as specifically described
herein.
* * * * *
References