U.S. patent application number 16/933678 was filed with the patent office on 2021-03-25 for lighting systems for providing tunable white light with functional diode emissions.
The applicant listed for this patent is ECOSENSE LIGHTING INC.. Invention is credited to Benjamin Harrison, Ihor Lys, Raghuram L.V. Petluri, Paul Kenneth Pickard.
Application Number | 20210092810 16/933678 |
Document ID | / |
Family ID | 1000005253315 |
Filed Date | 2021-03-25 |
View All Diagrams
United States Patent
Application |
20210092810 |
Kind Code |
A1 |
Petluri; Raghuram L.V. ; et
al. |
March 25, 2021 |
LIGHTING SYSTEMS FOR PROVIDING TUNABLE WHITE LIGHT WITH FUNCTIONAL
DIODE EMISSIONS
Abstract
The present disclosure provides systems for generating tunable
white light. The systems include a plurality of LED strings that
generate light with color points that fall within red, blue, and
green color ranges, with each LED string being driven with a
separately controllable drive current in order to tune the
generated light output. The systems can include an additional LED
string configured for functional applications that includes a type
of LED selected from 380-420 nm violet saturated LEDs, 200-280 nm
UVC saturated LEDs, 850-940 nm near-IR saturated LEDs, 580-620 nm
amber-orange/red saturated LEDs, and 460-490 nm long-blue saturated
LEDs.
Inventors: |
Petluri; Raghuram L.V.; (Los
Angeles, CA) ; Pickard; Paul Kenneth; (Los Angeles,
CA) ; Lys; Ihor; (Los Angeles, CA) ; Harrison;
Benjamin; (Los Angeles, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ECOSENSE LIGHTING INC. |
LOS ANGELES |
CA |
US |
|
|
Family ID: |
1000005253315 |
Appl. No.: |
16/933678 |
Filed: |
July 20, 2020 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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16694998 |
Nov 25, 2019 |
10721802 |
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16933678 |
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16049776 |
Jul 30, 2018 |
10492264 |
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16694998 |
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PCT/US18/20793 |
Mar 2, 2018 |
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16049776 |
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PCT/US16/15402 |
Jan 28, 2016 |
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PCT/US18/20793 |
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PCT/US16/15385 |
Jan 28, 2016 |
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PCT/US16/15402 |
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PCT/US16/15441 |
Jan 28, 2016 |
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PCT/US16/15385 |
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PCT/US16/15318 |
Jan 28, 2016 |
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PCT/US16/15441 |
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62616401 |
Jan 11, 2018 |
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62616404 |
Jan 11, 2018 |
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62616423 |
Jan 11, 2018 |
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62634798 |
Feb 23, 2018 |
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62616414 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 33/502 20130101;
F21Y 2115/10 20160801; F21K 9/00 20130101; H05B 45/20 20200101;
H01L 25/0753 20130101; F21Y 2113/13 20160801 |
International
Class: |
H05B 45/20 20060101
H05B045/20; F21K 9/00 20060101 F21K009/00 |
Claims
1. A semiconductor light emitting device comprising: first, second,
and third LED strings, with each LED string comprising one or more
LEDs having an associated luminophoric medium; wherein the first,
second, and third LED strings together with their associated
luminophoric mediums can comprise red, blue, and green channels
respectively, producing first, second, and third unsaturated color
points within red, blue, and green regions on the 1931 CIE
Chromaticity diagram, respectively; a control circuit can be
configured to adjust a fourth color point of a fourth unsaturated
light that results from a combination of the first, second, and
third unsaturated light, with the fourth color point falls within
a7-step MacAdam ellipse around any point on the black body locus
having a correlated color temperature between 1800K and 10000K.
2-69. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International
Patent Application No. PCT/US2018/020793 filed Mar. 2, 2018, which
claims the benefit of U.S. Provisional Patent Application No.
62/626,423 filed Jan. 11, 2018; is a continuation-in-part of
International Patent Application No. PCT/US2016/015402 filed Jan.
28, 2016; is a continuation-in-part of International Patent
Application No. PCT/US2016/015385 filed Jan. 28, 2016; is a
continuation-in-part of International Patent Application No.
PCT/US2016/015441 filed Jan. 28, 2016; is a continuation-in-part of
International Patent Application No. PCT/US2016/015318 filed Jan.
28, 2016; and claims the benefit of U.S. Provisional Patent
Application No. 62/616,401 filed Jan. 11, 2018; U.S. Provisional
Patent Application No. 62/616,404 filed Jan. 11, 2018; U.S.
Provisional Patent Application No. 62/616,414 filed Jan. 11, 2018;
U.S. Provisional Patent Application No. 62/616,423 filed Jan. 11,
2018; and U.S. Provisional Patent Application No. 62/634,798 filed
Feb. 23, 2018, the contents of which are incorporated by reference
herein in their entirety as if fully set forth herein.
FIELD OF THE DISCLOSURE
[0002] This disclosure is in the field of solid-state lighting. In
particular, the disclosure relates to devices for use in, and
methods for, providing tunable white light with high color
rendering performance.
BACKGROUND
[0003] A wide variety of light emitting devices are known in the
art including, for example, incandescent light bulbs, fluorescent
lights, and semiconductor light emitting devices such as light
emitting diodes ("LEDs").
[0004] There are a variety of resources utilized to describe the
light produced from a light emitting device, one commonly used
resource is 1931 CIE (Commission Internationale de l'Eclairage)
Chromaticity Diagram. The 1931 CIE Chromaticity Diagram maps out
the human color perception in terms of two CIE parameters x and y.
The spectral colors are distributed around the edge of the outlined
space, which includes all of the hues perceived by the human eye.
The boundary line represents maximum saturation for the spectral
colors, and the interior portion represents less saturated colors
including white light. The diagram also depicts the Planckian
locus, also referred to as the black body locus (BBL), with
correlated color temperatures, which represents the chromaticity
coordinates (i.e., color points) that correspond to radiation from
a black-body at different temperatures. Illuminants that produce
light on or near the BBL can thus be described in terms of their
correlated color temperatures (CCT). These illuminants yield
pleasing "white light" to human observers, with general
illumination typically utilizing CCT values between 1,800K and
10,000K.
[0005] Color rendering index (CRI) is described as an indication of
the vibrancy of the color of light being produced by a light
source. In practical terms, the CRI is a relative measure of the
shift in surface color of an object when lit by a particular lamp
as compared to a reference light source, typically either a
black-body radiator or the daylight spectrum. The higher the CRI
value for a particular light source, the better that the light
source renders the colors of various objects it is used to
illuminate.
[0006] Color rendering performance may be characterized via
standard metrics known in the art. Fidelity Index (Rf) and the
Gamut Index (Rg) can be calculated based on the color rendition of
a light source for 99 color evaluation samples ("CES"). The 99 CES
provide uniform color space coverage, are intended to be spectral
sensitivity neutral, and provide color samples that correspond to a
variety of real objects. Rf values range from 0 to 100 and indicate
the fidelity with which a light source renders colors as compared
with a reference illuminant. In practical terms, the Rf is a
relative measure of the shift in surface color of an object when
lit by a particular lamp as compared to a reference light source,
typically either a black-body radiator or the daylight spectrum.
The higher the Rf value for a particular light source, the better
that the light source renders the colors of various objects it is
used to illuminate. The Gamut Index Rg evaluates how well a light
source saturates or desaturates the 99 CES compared to the
reference source.
[0007] LEDs have the potential to exhibit very high power
efficiencies relative to conventional incandescent or fluorescent
lights. Most LEDs are substantially monochromatic light sources
that appear to emit light having a single color. Thus, the spectral
power distribution of the light emitted by most LEDs is tightly
centered about a "peak" wavelength, which is the single wavelength
where the spectral power distribution or "emission spectrum" of the
LED reaches its maximum as detected by a photo-detector. LEDs
typically have a full-width half-maximum wavelength range of about
10 nm to 30 nm, comparatively narrow with respect to the broad
range of visible light to the human eye, which ranges from
approximately from 380 nm to 800 nm.
[0008] In order to use LEDs to generate white light, LED lamps have
been provided that include two or more LEDs that each emit a light
of a different color. The different colors combine to produce a
desired intensity and/or color of white light. For example, by
simultaneously energizing red, green and blue LEDs, the resulting
combined light may appear white, or nearly white, depending on, for
example, the relative intensities, peak wavelengths and spectral
power distributions of the source red, green and blue LEDs. The
aggregate emissions from red, green, and blue LEDs typically
provide poor color rendering for general illumination applications
due to the gaps in the spectral power distribution in regions
remote from the peak wavelengths of the LEDs.
[0009] White light may also be produced by utilizing one or more
luminescent materials such as phosphors to convert some of the
light emitted by one or more LEDs to light of one or more other
colors. The combination of the light emitted by the LEDs that is
not converted by the luminescent material(s) and the light of other
colors that are emitted by the luminescent material(s) may produce
a white or near-white light.
[0010] LED lamps have been provided that can emit white light with
different CCT values within a range. Such lamps utilize two or more
LEDs, with or without luminescent materials, with respective drive
currents that are increased or decreased to increase or decrease
the amount of light emitted by each LED. By controllably altering
the power to the various LEDs in the lamp, the overall light
emitted can be tuned to different CCT values. The range of CCT
values that can be provided with adequate color rendering values
and efficiency is limited by the selection of LEDs.
[0011] The spectral profiles of light emitted by white artificial
lighting can impact circadian physiology, alertness, and cognitive
performance levels. Bright artificial light can be used in a number
of therapeutic applications, such as in the treatment of seasonal
affective disorder (SAD), certain sleep problems, depression, jet
lag, sleep disturbances in those with Parkinson's disease, the
health consequences associated with shift work, and the resetting
of the human circadian clock. Artificial lighting may change
natural processes, interfere with melatonin production, or disrupt
the circadian rhythm. Blue light may have a greater tendency than
other colored light to affect living organisms through the
disruption of their biological processes which can rely upon
natural cycles of daylight and darkness. Exposure to blue light
late in the evening and at night may be detrimental to one's
health. Some blue or royal blue light within lower wavelengths can
have hazardous effects to human eyes and skin, such as causing
damage to the retina.
[0012] Significant challenges remain in providing LED lamps that
can provide white light across a range of CCT values while
simultaneously achieving high efficiencies, high luminous flux,
good color rendering, and acceptable color stability. It is also a
challenge to provide lighting apparatuses that can provide
desirable lighting performance while allowing for the control of
circadian energy performance.
DISCLOSURE
[0013] The present disclosure provides aspects of semiconductor
light emitting devices comprising first, second, and third LED
strings, with each LED string comprising one or more LEDs having an
associated luminophoric medium. The first, second, and third LED
strings together with their associated luminophoric mediums can
comprise red, blue, and green channels respectively, producing
first, second, and third unsaturated color points within red, blue,
and green regions on the 1931 CIE Chromaticity diagram,
respectively. A control circuit can be configured to adjust a
fourth color point of a fourth unsaturated light that results from
a combination of the first, second, and third unsaturated light,
with the fourth color point falls within a 7-step MacAdam ellipse
around any point on the black body locus having a correlated color
temperature between 1800K and 10000K. The devices can be configured
to generate the fourth unsaturated light corresponding to a
plurality of points along a predefined path with the light
generated at each point having light with Rf greater than or equal
to about 85, Rg greater than or equal to about 90 and less than or
equal to about 110, or both. The devices can be configured to
generate the fourth unsaturated light corresponding to a plurality
of points along a predefined path with the light generated at each
point having light with Ra greater than or equal to about 92 along
points with correlated color temperature between about 1800K and
10000K, R9 greater than or equal to 80 along points with correlated
color temperature between about 2100K and about 10000K, or both.
The devices can be configured to generate the fourth unsaturated
light corresponding to a plurality of points along a predefined
path with the light generated at each point having EML greater than
or equal to about 0.5 along points with correlated color
temperature above about 2400K, EML greater than or equal to about
1.0 along points with correlated color temperature above about
5500K, or both. The devices can be configured to generate the
fourth unsaturated light corresponding to a plurality of points
along a predefined path with the light generated at each point
having light with R13 greater than or equal to about 92, R15
greater than or equal to about 88, or both. The blue color region
can be a region on the 1931 CIE Chromaticity Diagram defined by a
line connecting the ccx, ccy color coordinates of the infinity
point of the Planckian locus (0.242, 0.24) and (0.12, 0.068), the
Planckian locus from 4000K and infinite CCT, the constant CCT line
of 4000K, the line of purples, and the spectral locus. The red
color region can be a region on the 1931 CIE Chromaticity Diagram
defined by the spectral locus between the constant CCT line of
1600K and the line of purples, the line of purples, a line
connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47,
0.28), and the constant CCT line of 1600K. The green color region
can be a region on the 1931 CIE Chromaticity Diagram defined by the
constant CCT line of 6700K, the Planckian locus, and the spectral
locus. The spectral power distributions for the red, blue, and
green channels can fall within the minimum and maximum ranges shown
in Tables 1 and 2. The present disclosure provides aspects of
semiconductor light emitting devices comprising the first, second,
and third LED strings and a fourth LED string. The fourth LED
string can comprise a type of LED selected from 380-420 nm violet
saturated LEDs, 200-280 nm UVC saturated LEDs, 850-940 nm near-IR
saturated LEDs, 580-620 nm amber-orange/red saturated LEDs, and
460-490 nm long-blue saturated LEDs. The control circuit can be
further configured to adjust a sixth color point of a sixth
unsaturated light that results from a combination of the first,
second, and third unsaturated light and the a fifth saturated light
generated by the fourth LED string, with the sixth color point
falling within a 7-step MacAdam ellipse around any point on the
black body locus having a correlated color temperature between
1800K and 10000K. The LEDs of the fourth LED string can comprise
380-420 nm violet saturated LEDs and the device can be configured
to generate the sixth unsaturated light corresponding to a
plurality of points along a predefined path with one or more of the
following: the light generated at each point having light with Rf
greater than or equal to about 85, Rg greater than or equal to
about 95 and less than or equal to about 103, or both; the light
generated at each point having light with Rf greater than or equal
to about 90, Rg greater than or equal to about 97 and less than or
equal to about 103, or both; the light generated at each point
having light with Rf greater than or equal to about 90, Rg greater
than or equal to about 99 and less than or equal to about 103, or
both; the light generated at each point having light with Rf
greater than or equal to about 90, Rg greater than or equal to
about 97 and less than or equal to about 101, or both; the light
generated at each point having light with Ra greater than or equal
to about 93 along points with correlated color temperature between
about 1800K and 10000K, R9 greater than or equal to 85 along points
with correlated color temperature between about 1800K and about
10000K, or both; the light generated at each point having one or
more of EML greater than or equal to about 0.5 along points with
correlated color temperature above about 2700K, EML greater than or
equal to about 0.75 along points with correlated color temperature
above about 4000K, EML greater than or equal to about 1.0 along
points with correlated color temperature above about 5500K, and EML
greater than or equal to about 1.2 along points with correlated
color temperature above about 8000K; the light generated at each
point having light with R13 greater than or equal to about 94, R15
greater than or equal to about 90, or both; the light generated at
each point having light with R13 greater than or equal to about 95,
R15 greater than or equal to about 92, or both; and the light
generated at each point having light with R13 greater than or equal
to about 94, R15 greater than or equal to about 95, or both.
[0014] In some aspects, the present disclosure provides methods of
generating white light, the methods comprising providing first,
second, and third LED strings, with each LED string comprising one
or more LEDs having an associated luminophoric medium, providing a
fourth LED string, wherein the first, second, and third LED strings
together with their associated luminophoric mediums comprise red,
blue, and green channels respectively, producing first, second, and
third unsaturated light with color points within red, blue, and
green regions on the 1931 CIE Chromaticity diagram, respectively,
providing a control circuit configured to adjust a fourth color
point of a fourth unsaturated light that results from a combination
of the first, second, and third, unsaturated light, with the fourth
color point falls within a 7-step MacAdam ellipse around any point
on the black body locus having a correlated color temperature
between 1800K and 10000K, wherein the control circuit is further
configured to adjust a sixth color point of a sixth unsaturated
light that results from a combination of the first, second, and
third unsaturated light and a fifth saturated light from the fourth
LED string, generating light in a first operating mode with two or
more of the first, second, and third unsaturated light by combining
the two or more generated unsaturated lights to create the fourth
unsaturated light, and generating light in a second operating mode
with two or more of the first, second, and third unsaturated light
and the fifth saturated light by combining the two or more
generated unsaturated/saturated light to create the sixth
unsaturated light. In some implementations, the LEDs of the fourth
LED string comprise a type of LED selected from 380-420 nm violet
saturated LEDs, 200-280 nm UVC saturated LEDs, 850-940 nm near-IR
saturated LEDs, 580-620 nm amber-orange/red saturated LEDs, and
460-490 nm long-blue saturated LEDs. In some implementations, the
LEDs of the fourth LED string comprise 380-420 nm violet saturated
LEDs. In some implementations, the LEDs of the fourth LED string
comprise 200-280 nm UVC saturated LEDs. In some implementations,
the LEDs of the fourth LED string comprise 850-940 nm near-IR
saturated LEDs. In some implementations, the LEDs of the fourth LED
string comprise 580-620 nm amber-orange/red saturated LEDs. In some
implementations, the control circuit can be configured to switch
between the first operating mode and the second operating mode to
provide the fourth unsaturated light and the sixth unsaturated
light having substantially the same ccx, ccy coordinates on the
1931 CIE Chromaticity Diagram. In some implementations, the fourth
unsaturated light and the sixth unsaturated light can have color
points within about 1.0 standard deviations of color matching
(SDCM). In some implementations, the fourth unsaturated light and
the sixth unsaturated light can have color points within about 0.5
standard deviations of color matching (SDCM). In some
implementations, the sixth unsaturated light can have improved
color-rendering performance in comparison to the fourth unsaturated
light in one or more of Ra, R9, Rf, and Rg.
[0015] The general disclosure and the following further disclosure
are exemplary and explanatory only and are not restrictive of the
disclosure, as defined in the appended claims. Other aspects of the
present disclosure will be apparent to those skilled in the art in
view of the details as provided herein. In the figures, like
reference numerals designate corresponding parts throughout the
different views. All callouts and annotations are hereby
incorporated by this reference as if fully set forth herein.
DRAWINGS
[0016] The summary, as well as the following detailed description,
is further understood when read in conjunction with the appended
drawings. For the purpose of illustrating the disclosure, there are
shown in the drawings exemplary implementations of the disclosure;
however, the disclosure is not limited to the specific methods,
compositions, and devices disclosed. In addition, the drawings are
not necessarily drawn to scale. In the drawings:
[0017] FIG. 1 illustrates aspects of light emitting devices
according to the present disclosure;
[0018] FIG. 2 illustrates aspects of light emitting devices
according to the present disclosure;
[0019] FIG. 3 depicts a graph of a 1931 CIE Chromaticity Diagram
illustrating the location of the Planckian locus;
[0020] FIGS. 4A-4D illustrate some aspects of light emitting
devices according to the present disclosure, including some
suitable color ranges for light generated by components of the
devices;
[0021] FIG. 5 illustrates some aspects of light emitting devices
according to the present disclosure, including some suitable color
ranges for light generated by components of the devices;
[0022] FIG. 6 illustrates some aspects of light emitting devices
according to the present disclosure, including some suitable color
ranges for light generated by components of the devices;
[0023] FIGS. 7A-7F show tables of data of color rendering
characteristics of an implementation of the present disclosure;
[0024] FIGS. 8A-8F are tables of data of relative spectral power
versus wavelength regions for some suitable color points of light
generated by components of devices of the present disclosure;
and
[0025] FIGS. 9A-9F are tables of data of relative spectral power
versus wavelength regions for some suitable color points of light
generated by components of devices of the present disclosure.
[0026] All descriptions and callouts in the Figures are hereby
incorporated by this reference as if fully set forth herein.
FURTHER DISCLOSURE
[0027] The present disclosure may be understood more readily by
reference to the following detailed description taken in connection
with the accompanying figures and examples, which form a part of
this disclosure. It is to be understood that this disclosure is not
limited to the specific devices, methods, applications, conditions
or parameters described and/or shown herein, and that the
terminology used herein is for the purpose of describing particular
exemplars by way of example only and is not intended to be limiting
of the claimed disclosure. Also, as used in the specification
including the appended claims, the singular forms "a," "an," and
"the" include the plural, and reference to a particular numerical
value includes at least that particular value, unless the context
clearly dictates otherwise. The term "plurality", as used herein,
means more than one. When a range of values is expressed, another
exemplar includes from the one particular value and/or to the other
particular value. Similarly, when values are expressed as
approximations, by use of the antecedent "about," it will be
understood that the particular value forms another exemplar. All
ranges are inclusive and combinable.
[0028] It is to be appreciated that certain features of the
disclosure which are, for clarity, described herein in the context
of separate exemplar, may also be provided in combination in a
single exemplary implementation. Conversely, various features of
the disclosure that are, for brevity, described in the context of a
single exemplary implementation, may also be provided separately or
in any subcombination. Further, reference to values stated in
ranges include each and every value within that range.
[0029] In one aspect, the present disclosure provides semiconductor
light emitting devices 100 that can have a plurality of light
emitting diode (LED) strings. Each LED string can have one, or more
than one, LED. As depicted schematically in FIG. 1, the device 100
may comprise one or more LED strings (101A/101B/101C/101D) that
emit light (schematically shown with arrows). In some instances,
the LED strings can have recipient luminophoric mediums
(102A/102B/102C/102D) associated therewith. The light emitted from
the LED strings, combined with light emitted from the recipient
luminophoric mediums, can be passed through one or more optical
elements 103. Optical elements 103 may be one or more diffusers,
lenses, light guides, reflective elements, or combinations thereof.
In some implementations, one or more of the LED strings
101A/101B/101C/101D may be provided without an associated
luminophoric medium. In further implementations, three of the LED
strings 101A/101B/101C can be provided with an associated
luminophoric medium for each, and the fourth LED string 101D can be
provided without an associated luminophoric medium.
[0030] A recipient luminophoric medium 102A, 102B, 102C, or 102D
includes one or more luminescent materials and is positioned to
receive light that is emitted by an LED or other semiconductor
light emitting device. In some implementations, recipient
luminophoric mediums include layers having luminescent materials
that are coated or sprayed directly onto a semiconductor light
emitting device or on surfaces of the packaging thereof, and clear
encapsulants that include luminescent materials that are arranged
to partially or fully cover a semiconductor light emitting device.
A recipient luminophoric medium may include one medium layer or the
like in which one or more luminescent materials are mixed, multiple
stacked layers or mediums, each of which may include one or more of
the same or different luminescent materials, and/or multiple spaced
apart layers or mediums, each of which may include the same or
different luminescent materials. Suitable encapsulants are known by
those skilled in the art and have suitable optical, mechanical,
chemical, and thermal characteristics. In some implementations,
encapsulants can include dimethyl silicone, phenyl silicone,
epoxies, acrylics, and polycarbonates. In some implementations, a
recipient luminophoric medium can be spatially separated (i.e.,
remotely located) from an LED or surfaces of the packaging thereof.
In some implementations, such spatial segregation may involve
separation of a distance of at least about 1 mm, at least about 2
mm, at least about 5 mm, or at least about 10 mm. In certain
embodiments, conductive thermal communication between a spatially
segregated luminophoric medium and one or more electrically
activated emitters is not substantial. Luminescent materials can
include phosphors, scintillators, day glow tapes, nanophosphors,
inks that glow in visible spectrum upon illumination with light,
semiconductor quantum dots, or combinations thereof. In some
implementations, the luminescent materials may comprise phosphors
comprising one or more of the following materials:
BaMg.sub.2Al.sub.6O.sub.27:Eu.sup.2+,
BaMg.sub.2Al.sub.6O.sub.27:Eu.sup.2+,Mn.sup.2+, CaSiO.sub.3:Pb,Mn,
CaWO.sub.4:Pb, MgWO.sub.4, Sr.sub.5Cl(PO.sub.4).sub.3:Eu.sup.2+,
Sr.sub.2P.sub.2O.sub.7:Sn.sup.2+, Sr.sub.6P.sub.5BO.sub.20:Eu,
CaF(PO.sub.4).sub.3:Sb, (Ba,Ti).sub.2P.sub.2O.sub.7:Ti,
SrsF(PO.sub.4).sub.3:Sb,Mn, (La,Ce,Tb)PO.sub.4:Ce,Tb,
(Ca,Zn,Mg).sub.3(PO.sub.4).sub.2:Sn,
(Sr,Mg).sub.3(PO.sub.4).sub.2:Sn, Y.sub.2O.sub.3:Eu.sup.3*,
Mg.sub.4(F)GeO.sub.6:Mn, LaMgAl.sub.11O.sub.9:Ce, LaPO.sub.4:Ce,
SrAl.sub.12O.sub.19:Ce, BaSi.sub.2O.sub.5:Pb, SrB.sub.4O.sub.7:Eu,
Sr.sub.2MgSi.sub.2O.sub.7:Pb, Gd.sub.2O.sub.2S:Tb,
Gd.sub.2O.sub.2S:Eu, Gd.sub.2O.sub.2S:Pr, Gd.sub.2O.sub.2S:Pr,Ce,F,
Y.sub.2O.sub.2S:Tb, Y.sub.2O.sub.2S:Eu, Y.sub.2O.sub.2S:Pr,
Zn(0.5)Cd(0.4)S:Ag, Zn(0.4)Cd(0.6)S:Ag, Y.sub.2SiO.sub.5:Ce,
YAlO.sub.3:Ce, Y.sub.3(Al,Ga).sub.5O.sub.12:Ce, CdS:In, ZnO:Ga,
ZnO:Zn, (Zn,Cd)S:Cu,Al, ZnCdS:Ag,Cu, ZnS:Ag, ZnS:Cu, NaI:Tl,
CsI:Tl, .sup.6LiF/ZnS:Ag, .sup.6LiF/ZnS:Cu,Al,Au, ZnS:Cu,Al,
ZnS:Cu,Au,Al, CaAlSiN.sub.3:Eu, (Sr,Ca)AlSiN.sub.3:Eu,
(Ba,Ca,Sr,Mg).sub.2SiO.sub.4:Eu, Lu.sub.3AsO.sub.12:Ce,
Eu.sup.3+(Gd.sub.0.9Y.sub.0.1).sub.3Al.sub.5O.sub.12:Bi.sup.3+,Tb.sup.3,
Y.sub.3Al.sub.5O.sub.12:Ce, (La,Y).sub.3Si.sub.6N.sub.11:Ce,
Ca.sub.2AlSi.sub.3O.sub.2N.sub.5:Ce.sup.3+,
Ca.sub.2AlSi.sub.3O.sub.2N.sub.5:Eu.sup.2+,
BaMgAl.sub.10O.sub.7:Eu, Sr.sub.5(PO.sub.4).sub.3C: Eu,
(Ba,Ca,Sr,Mg).sub.2SiO.sub.4:Eu,
Si.sub.6-zAl.sub.zN.sub.8-zO.sub.z:Eu (wherein 0<z.ltoreq.4.2);
M.sub.3Si.sub.6O.sub.12N.sub.2:Eu (wherein M=alkaline earth metal
element), (Mg,Ca,Sr,Ba)Si.sub.2O.sub.2N.sub.2:Eu,
Sr.sub.4Al.sub.14O.sub.25:Eu, (Ba,Sr,Ca)Al.sub.2O.sub.4:Eu,
(Sr,Ba)Al.sub.2Si.sub.2O.sub.8:Eu, (Ba,Mg).sub.2SiO.sub.4:Eu,
(Ba,Sr,Ca).sub.2(Mg, Zn)Si.sub.2O.sub.7:Eu,
(Ba,Ca,Sr,Mg).sub.9(Sc,Y,Lu,Gd).sub.2(Si,Ge).sub.6O.sub.24: Eu,
Y.sub.2SiO.sub.5:CeTb,
Sr.sub.2P.sub.2O.sub.7-Sr.sub.2B.sub.2O.sub.5:Eu,
Sr.sub.2Si.sub.3O.sub.8-2SrCl.sub.2:Eu, Zn.sub.2SiO.sub.4:Mn,
CeMgAl.sub.11O.sub.19:Tb, Y.sub.3Al.sub.5O.sub.12:Tb,
Ca.sub.2Y.sub.8(SiO.sub.4).sub.6O.sub.2:Tb,
La.sub.3Ga.sub.5SiO.sub.14:Tb, (Sr,Ba,Ca)Ga.sub.2S.sub.4:Eu,Tb,Sm,
Y.sub.3(Al,Ga).sub.5O.sub.12:Ce,
(Y,Ga,Tb,La,Sm,Pr,Lu).sub.3(Al,Ga).sub.5O.sub.12:Ce,
Ca.sub.3Sc.sub.2Si.sub.3O.sub.12:Ce,
Ca.sub.3(Sc,Mg,Na,Li).sub.2Si.sub.3O.sub.12:Ce,
CaSc.sub.2O.sub.4:Ce, Eu-activated P-Sialon, SrAl.sub.2O.sub.4:Eu,
(La,Gd,Y).sub.2O.sub.2S:Tb, CeLaPO.sub.4:Tb, ZnS:Cu,Al,
ZnS:Cu,Au,Al, (Y,Ga,Lu,Sc,La)BO.sub.3:Ce,Tb,
Na.sub.2Gd.sub.2B.sub.2O.sub.7:Ce,Tb,
(Ba,Sr).sub.2(Ca,Mg,Zn)B.sub.2O.sub.6:K,Ce,Tb, CasMg
(SiO.sub.4).sub.4C.sub.2:Eu,Mn,
(Sr,Ca,Ba)(Al,Ga,In).sub.2S.sub.4:Eu, (Ca,Sr).sub.8
(Mg,Zn)(SiO.sub.4).sub.4Cl.sub.2:Eu,Mn,
M.sub.3Si.sub.6O.sub.9N.sub.4:Eu,
Sr.sub.5Al.sub.5Si.sub.21O.sub.2N.sub.35:Eu,
Sr.sub.3Si.sub.3Al.sub.3N.sub.21O.sub.2:Eu,
(Mg,Ca,Sr,Ba).sub.2Si.sub.5N.sub.8:Eu, (La,Y).sub.2O.sub.2S:Eu,
(Y,La,Gd,Lu).sub.2O.sub.2S:Eu, Y(V,P)O.sub.4:Eu,
(Ba,Mg).sub.2SiO.sub.4:Eu,Mn, (Ba,Sr, Ca,Mg).sub.2SiO.sub.4:Eu,Mn,
LiW.sub.2O.sub.8:Eu, LiW.sub.2O.sub.8:Eu,Sm,
Eu.sub.2W.sub.2O.sub.9, Eu.sub.2W.sub.2O.sub.9:Nb and
Eu.sub.2W.sub.2O.sub.9:Sm, (Ca,Sr)S:Eu, YAlO.sub.3:Eu,
Ca.sub.2Y.sub.8(SiO.sub.4).sub.6O.sub.2:Eu,
LiY.sub.9(SiO.sub.4).sub.6O.sub.2:Eu,
(Y,Gd).sub.3Al.sub.5O.sub.12:Ce, (Tb,Gd).sub.3Al.sub.5O.sub.12:Ce,
(Mg,Ca,Sr,Ba).sub.2Si.sub.5(N,O).sub.5:Eu,
(Mg,Ca,Sr,Ba)Si(N,O).sub.2:Eu, (Mg,Ca,Sr,Ba)AlSi(N,O).sub.3:Eu,
(Sr,Ca,Ba,Mg).sub.10(PO.sub.4).sub.6Cl.sub.2:Eu, Mn,
Eu,Ba.sub.3MgSi.sub.2O.sub.8:Eu,Mn,
(Ba,Sr,Ca,Mg).sub.3(Zn,Mg)Si.sub.2O.sub.8:Eu,Mn,
(k-x)MgO.xAF.sub.2.GeO.sub.2:yMn.sup.4+ (wherein k=2.8 to 5, x=0.1
to 0.7, y=0.005 to 0.015, A=Ca, Sr, Ba, Zn or a mixture thereof),
Eu-activated .alpha.-Sialon, (Gd,Y,Lu,La).sub.2O.sub.3:Eu, Bi,
(Gd,Y,Lu,La).sub.2O.sub.2S:Eu,Bi, (Gd,Y,Lu,La)VO.sub.4:Eu,Bi,
SrY.sub.2S.sub.4:Eu,Ce, CaLa.sub.2S.sub.4:Ce,Eu,
(Ba,Sr,Ca)MgP.sub.2O.sub.7:Eu, Mn,
(Sr,Ca,Ba,Mg,Zn).sub.2P.sub.2O.sub.7:Eu,Mn,
(Y,Lu).sub.2WO.sub.6:Eu,Ma, (Ba,Sr,Ca).sub.xSi.sub.yN.sub.z:Eu,Ce
(wherein x, y and z are integers equal to or greater than
1),(Ca,Sr,Ba,Mg).sub.10(PO.sub.4).sub.6(F,Cl,Br,OH):Eu,Mn,
((Y,Lu,Gd,Tb).sub.1-x-ySc.sub.xCe.sub.y).sub.2(Ca,Mg)(Mg,Zn).sub.2+rSi.su-
b.z-qGe.sub.qO.sub.12+.delta., SrAlSi.sub.4N.sub.7,
Sr.sub.2Al.sub.2Si.sub.9O.sub.2N.sub.14:Eu,
M.sup.1.sub.aM.sup.2.sub.bM.sup.3.sub.cO (wherein M=activator
element including at least Ce, M.sup.2=bivalent metal element,
M.sup.3=trivalent metal element, 0.0001.ltoreq.a.ltoreq.0.2,
0.8.ltoreq.b.ltoreq.1.2, 1.6.ltoreq.c.ltoreq.2.4 and
3.2.ltoreq.d.ltoreq.4.8), A.sub.2+xM.sub.yMn.sub.zF.sub.n (wherein
A=Na and/or K; M=Si and Al, and -1.ltoreq.x.ltoreq.1,
0.9.ltoreq.y+z.ltoreq.0.1, 0.001.ltoreq.z.ltoreq.0.4 and
5.ltoreq.n.ltoreq.7), KSF/KSNAF, or (La.sub.1-x-y, Eu.sub.x,
Ln.sub.y).sub.2O.sub.2S (wherein 0.02.ltoreq.x.ltoreq.0.50 and
0.ltoreq.y.ltoreq.0.50, Ln=Y.sup.3+, Gd.sup.3+, Lu.sup.3+,
Sc.sup.3+, Sm.sup.3+ or Er.sup.3+). In some preferred
implementations, the luminescent materials may comprise phosphors
comprising one or more of the following materials:
CaAlSiN.sub.3:Eu, (Sr,Ca)AlSiN.sub.3:Eu, BaMgAl.sub.10O.sub.17:Eu,
(Ba,Ca,Sr,Mg).sub.2SiO.sub.4:Eu, [-SiAlON,
Lu.sub.3Al.sub.5O.sub.12:Ce,
Eu.sup.3+(Cd.sub.0.9Y.sub.0.1).sub.3Al.sub.5O.sub.12:Bi.sup.3+,Tb.sup.3+,
Y.sub.3Al.sub.5O.sub.12:Ce, La.sub.3Si.sub.6N.sub.11:Ce,
(La,Y).sub.3Si.sub.6N.sub.11:Ce,
Ca.sub.2AlSi.sub.3O.sub.2N.sub.5:Ce.sup.3+,
Ca.sub.2AlSi.sub.3O.sub.2N.sub.5:Ce.sup.3+,Eu.sup.2+,
Ca.sub.2AlSi.sub.3O.sub.2N:Eu.sup.2+,
BaMgAl.sub.10O.sub.17:Eu.sup.2+,
Sr.sub.4.5Eu.sub.0.5(PO.sub.4).sub.3C, or
M.sup.1.sub.aM.sup.2.sub.bM.sup.3.sub.cO.sub.d (wherein
M.sup.1=activator element comprising Ce, M.sup.2=bivalent metal
element, M.sup.3=trivalent metal element,
0.0001.ltoreq.a.ltoreq.0.2, 0.8.ltoreq.b.ltoreq.1.2,
1.6.ltoreq.c.ltoreq.2.4 and 3.2.ltoreq.d.ltoreq.4.8). In further
preferred implementations, the luminescent materials may comprise
phosphors comprising one or more of the following materials:
CaAlSiN.sub.3:Eu, BaMgAl.sub.10O.sub.17:Eu,
Lu.sub.3Al.sub.5O.sub.12:Ce, or Y.sub.3Al.sub.5O.sub.12:Ce.
[0031] Some implementations of the present invention relate to use
of solid state emitter packages. A solid state emitter package
typically includes at least one solid state emitter chip that is
enclosed with packaging elements to provide environmental and/or
mechanical protection, color selection, and light focusing, as well
as electrical leads, contacts or traces enabling electrical
connection to an external circuit. Encapsulant material, optionally
including luminophoric material, may be disposed over solid state
emitters in a solid state emitter package. Multiple solid state
emitters may be provided in a single package. A package including
multiple solid state emitters may include at least one of the
following: a single leadframe arranged to conduct power to the
solid state emitters, a single reflector arranged to reflect at
least a portion of light emanating from each solid state emitter, a
single submount supporting each solid state emitter, and a single
lens arranged to transmit at least a portion of light emanating
from each solid state emitter. Individual LEDs or groups of LEDs in
a solid state package (e.g., wired in series) may be separately
controlled. As depicted schematically in FIG. 2, multiple solid
state packages 200 may be arranged in a single semiconductor light
emitting device 100. Individual solid state emitter packages or
groups of solid state emitter packages (e.g., wired in series) may
be separately controlled. Separate control of individual emitters,
groups of emitters, individual packages, or groups of packages, may
be provided by independently applying drive currents to the
relevant components with control elements known to those skilled in
the art. In one embodiment, at least one control circuit 201 a may
include a current supply circuit configured to independently apply
an on-state drive current to each individual solid state emitter,
group of solid state emitters, individual solid state emitter
package, or group of solid state emitter packages. Such control may
be responsive to a control signal (optionally including at least
one sensor 202 arranged to sense electrical, optical, and/or
thermal properties and/or environmental conditions), and a control
system 203 may be configured to selectively provide one or more
control signals to the at least one current supply circuit. In
various embodiments, current to different circuits or circuit
portions may be pre-set, user-defined, or responsive to one or more
inputs or other control parameters. The design and fabrication of
semiconductor light emitting devices are well known to those
skilled in the art, and hence further description thereof will be
omitted.
[0032] FIG. 3 illustrates a 1931 International Commission on
Illumination (CIE) chromaticity diagram. The 1931 CIE Chromaticity
diagram is a two-dimensional chromaticity space in which every
visible color is represented by a point having x- and
y-coordinates. Fully saturated (monochromatic) colors appear on the
outer edge of the diagram, while less saturated colors (which
represent a combination of wavelengths) appear on the interior of
the diagram. The term "saturated", as used herein, means having a
purity of at least 85%, the term "purity" having a well-known
meaning to persons skilled in the art, and procedures for
calculating purity being well-known to those of skill in the art.
The Planckian locus, or black body locus (BBL), represented by line
150 on the diagram, follows the color an incandescent black body
would take in the chromaticity space as the temperature of the
black body changes from about 1000K to 10,000 K. The black body
locus goes from deep red at low temperatures (about 1000 K) through
orange, yellowish white, white, and finally bluish white at very
high temperatures. The temperature of a black body radiator
corresponding to a particular color in a chromaticity space is
referred to as the "correlated color temperature." In general,
light corresponding to a correlated color temperature (CCT) of
about 2700 K to about 6500 K is considered to be "white" light. In
particular, as used herein, "white light" generally refers to light
having a chromaticity point that is within a 10-step MacAdam
ellipse of a point on the black body locus having a CCT between
2700K. and 6500K. However, it will be understood that tighter or
looser definitions of white light can be used if desired. For
example, white light can refer to light having a chromaticity point
that is within a seven step MacAdam ellipse of a point on the black
body locus having a CCT between 2700K and 6500K. The distance from
the black body locus can be measured in the CIE 1960 chromaticity
diagram, and is indicated by the symbol .DELTA.uv, or DUV. If the
chromaticity point is above the Planckian locus the DUV is denoted
by a positive number; if the chromaticity point is below the locus,
DUV is indicated with a negative number. If the DUV is sufficiently
positive, the light source may appear greenish or yellowish at the
same CCT. If the DUV is sufficiently negative, the light source can
appear to be purple or pinkish at the same CCT. Observers may
prefer light above or below the Planckian locus for particular CCT
values. DUV calculation methods are well known by those of ordinary
skill in the art and are more fully described in ANSI C78.377,
American National Standard for Electric Lamps--Specifications for
the Chromaticity of Solid State Lighting (SSL) Products, which is
incorporated by reference herein in its entirety for all purposes.
A point representing the CIE Standard Illuminant D65 is also shown
on the diagram. The D65 illuminant is intended to represent average
daylight and has a CCT of approximately 6500K and the spectral
power distribution is described more fully in Joint ISO/CIE
Standard, ISO 10526:1999/CIE S005/E-1998, CIE Standard Illuminants
for Colorimetry, which is incorporated by reference herein in its
entirety for all purposes.
[0033] The light emitted by a light source may be represented by a
point on a chromaticity diagram, such as the 1931 CIE chromaticity
diagram, having color coordinates denoted (ccx, ccy) on the X-Y
axes of the diagram. A region on a chromaticity diagram may
represent light sources having similar chromaticity
coordinates.
[0034] The ability of a light source to accurately reproduce color
in illuminated objects can be characterized using the color
rendering index ("CR1"), also referred to as the CIE Ra value. The
Ra value of a light source is a modified average of the relative
measurements of how the color rendition of an illumination system
compares to that of a reference black-body radiator or daylight
spectrum when illuminating eight reference colors R1-R8. Thus, the
Ra value is a relative measure of the shift in surface color of an
object when lit by a particular lamp. The Ra value equals 100 if
the color coordinates of a set of test colors being illuminated by
the illumination system are the same as the coordinates of the same
test colors being irradiated by a reference light source of
equivalent CCT. For CCTs less than 5000K, the reference illuminants
used in the CRI calculation procedure are the SPDs of blackbody
radiators; for CCTs above 5000K, imaginary SPDs calculated from a
mathematical model of daylight are used. These reference sources
were selected to approximate incandescent lamps and daylight,
respectively. Daylight generally has an Ra value of nearly 100,
incandescent bulbs have an Ra value of about 95, fluorescent
lighting typically has an Ra value of about 70 to 85, while
monochromatic light sources have an Ra value of essentially zero.
Light sources for general illumination applications with an Ra
value of less than 50 are generally considered very poor and are
typically only used in applications where economic issues preclude
other alternatives. The calculation of CIE Ra values is described
more fully in Commission Internationale de l'Eclairage. 1995.
Technical Report: Method of Measuring and Spec'ing Colour Rendering
Properties of Light Sources, CIE No. 13.3-1995. Vienna, Austria:
Commission Internationale de l'Eclairage, which is incorporated by
reference herein in its entirety for all purposes. In addition to
the Ra value, a light source can also be evaluated based on a
measure of its ability to render seven additional colors R9-R15,
which include realistic colors like red, yellow, green, blue,
caucasian skin color (R13), tree leaf green, and asian skin color
(R15), respectively. The ability to render the saturated red
reference color R9 can be expressed with the R9 color rendering
value ("R9 value"). Light sources can further be evaluated by
calculating the gamut area index ("GAI"). Connecting the rendered
color points from the determination of the CIE Ra value in two
dimensional space will form a gamut area. Gamut area index is
calculated by dividing the gamut area formed by the light source
with the gamut area formed by a reference source using the same set
of colors that are used for CRI. GAI uses an Equal Energy Spectrum
as the reference source rather than a black body radiator. A gamut
area index related to a black body radiator ("GAIBB") can be
calculated by using the gamut area formed by the blackbody radiator
at the equivalent CCT to the light source.
[0035] The ability of a light source to accurately reproduce color
in illuminated objects can be characterized using the metrics
described in IES Method for Evaluating Light Source Color
Rendition, Illuminating Engineering Society, Product ID: TM-30-15
(referred to herein as the "TM-30-15 standard"), which is
incorporated by reference herein in its entirety for all purposes.
The TM-30-15 standard describes metrics including the Fidelity
Index (RI) and the Gamut Index (Rg) that can be calculated based on
the color rendition of a light source for 99 color evaluation
samples ("CES"). The 99 CES provide uniform color space coverage,
are intended to be spectral sensitivity neutral, and provide color
samples that correspond to a variety of real objects. Rf values
range from 0 to 100 and indicate the fidelity with which a light
source renders colors as compared with a reference illuminant. Rg
values provide a measure of the color gamut that the light source
provides relative to a reference illuminant. The range of Rg
depends upon the Rf value of the light source being tested. The
reference illuminant is selected depending on the CCT. For CCT
values less than or equal to 4500K, Planckian radiation is used.
For CCT values greater than or equal to 5500K, CIE Daylight
illuminant is used. Between 4500K and 5500K a proportional mix of
Planckian radiation and the CIE Daylight illuminant is used,
according to the following equation:
S r , M ( .lamda. , T t ) = 5500 - T t 1000 S r , P ( .lamda. , T t
) + ( 1 - 5500 - T t 1000 ) S r , D ( .lamda. , T t ) ,
##EQU00001##
where Tt is the CCT value, S.sub.r,M(.lamda., T.sub.t) is the
proportional mix reference illuminant, S.sub.r,P(.lamda., T.sub.t)
is Planckian radiation, and S.sub.r,D (.lamda., T.sub.t) is the CIE
Daylight illuminant.
[0036] Circadian illuminance (CLA) is a measure of circadian
effective light, spectral irradiance distribution of the light
incident at the cornea weighted to reflect the spectral sensitivity
of the human circadian system as measured by acute melatonin
suppression after a one-hour exposure, and CS, which is the
effectiveness of the spectrally weighted irradiance at the cornea
from threshold (CS=0.1) to saturation (CS=0.7). The values of CLA
are scaled such that an incandescent source at 2856K (known as CIE
Illuminant A) which produces 1000 lux (visual lux) will produce
1000 units of circadian lux (CLA). CS values are transformed CLA
values and correspond to relative melotonian suppression after one
hour of light exposure for a 2.3 mm diameter pupil during the
mid-point of melotonian production. CS is calculated from
CS = | 0.7 ( 1 - 1 1 + ( CLA 355.7 ) ^ 1.126 ) . ##EQU00002##
The calculation of CLA is more fully described in Rea et al.,
"Modelling the spectral sensitivity of the human circadian system,"
Lighting Research and Technology, 2011; 0: 1-12, and Figueiro et
al., "Designing with Circadian Stimulus", October 2016, LD+A
Magazine, Illuminating Engineering Society of North America, which
are incorporated by reference herein in its entirety for all
purposes. Figueiro et al. describe that exposure to a CS of 0.3 or
greater at the eye, for at least one hour in the early part of the
day, is effective for stimulating the circadian system and is
associated with better sleep and improved behavior and mood.
[0037] Equivalent Melanopic Lux (EML) provides a measure of
photoreceptive input to circadian and neurophysiological light
responses in humans, as described in Lucas et al., "Measuring and
using light in the melanopsin age." Trends in Neurosciences,
January 2014, Vol. 37, No. 1, pages 1-9, which is incorporated by
reference herein in its entirety, including all appendices, for all
purposes. Melanopic lux is weighted to a photopigment with
.lamda.max 480 nm with pre-receptoral filtering based on a 32 year
old standard observer, as described more fully in the Appendix A,
Supplementary Data to Lucas et al. (2014), User Guide: Irradiance
Toolbox (Oxford 18.sup.th October 2013), University of Manchester,
Lucas Group, which is incorporated by reference herein in its
entirety for all purposes.
[0038] Blue Light Hazard (BLH) provides a measure of potential for
a photochemical induced retinal injury that results from radiation
exposure. Blue Light Hazard is described in IEC/EN 62471,
Photobiological Safety of Lamps and Lamp Systems and Technical
Report IEC/TR 62778: Application of IEC 62471 for the assessment of
blue light hazard to light sources and luminaires, which are
incorporated by reference herein in their entirety for all
purposes. A BLH factor can be expressed in (weighted power/lux) in
units of .mu.W/cm.sup.2/lux.
[0039] In some aspects the present disclosure relates to lighting
devices and methods to provide light having particular vision
energy and circadian energy performance. Many figures of merit are
known in the art, some of which are described in Ji Hye Oh, Su Ji
Yang and Young Rag Do, "Healthy, natural, efficient and tunable
lighting: four-package white LEDs for optimizing the circadian
effect, color quality and vision performance," Light: Science &
Applications (2014) 3: e141-e149, which is incorporated herein in
its entirety, including supplementary information, for all
purposes. Luminous efficacy of radiation ("LER") can be calculated
from the ratio of the luminous flux to the radiant flux (S(1)),
i.e. the spectral power distribution of the light source being
evaluated, with the following equation:
LER ( lm W ) = 683 ( lm W ) .intg. V ( .lamda. ) S ( .lamda. ) d
.lamda. .intg. S ( .lamda. ) d .lamda. . ##EQU00003##
Circadian efficacy of radiation ("CER") can be calculated from the
ratio of circadian luminous flux to the radiant flux, with the
following equation:
CER ( blm W ) = 683 ( blm W ) .intg. C ( .lamda. ) S ( .lamda. ) d
.lamda. .intg. S ( .lamda. ) d .lamda. . ##EQU00004##
Circadian action factor ("CAF") can be defined by the ratio of CER
to LER, with the following equation:
( blm lm ) = CER ( blm W ) LER ( lm W ) . ##EQU00005##
The term "blm" refers to biolumens, units for measuring circadian
flux, also known as circadian lumens. The term "lm" refers to
visual lumens. V(.lamda.) is the photopic spectral luminous
efficiency function and C(.lamda.) is the circadian spectral
sensitivity function. The calculations herein use the circadian
spectral sensitivity function, C(.lamda.), from Gall et al.,
Proceedings of the CIE Symposium 2004 on Light and Health:
Non-Visual Effects, 30 September-2 Oct. 2004; Vienna, Austria 2004.
CIE: Wien, 2004, pp 129-132, which is incorporated herein in its
entirety for all purposes. By integrating the amount of light
(milliwatts) within the circadian spectral sensitivity function and
dividing such value by the number of photopic lumens, a relative
measure of melatonin suppression effects of a particular light
source can be obtained. A scaled relative measure denoted as
melatonin suppressing milliwatts per hundred lumens may be obtained
by dividing the photopic lumens by 100. The term "melatonin
suppressing milliwatts per hundred lumens" consistent with the
foregoing calculation method is used throughout this application
and the accompanying figures and tables.
[0040] The ability of a light source to provide illumination that
allows for the clinical observation of cyanosis is based upon the
light source's spectral power density in the red portion of the
visible spectrum, particularly around 660 nm. The cyanosis
observation index ("COI") is defined by AS/NZS 1680.2.5 Interior
Lighting Part 2.5: Hospital and Medical Tasks, Standards Australia,
1997 which is incorporated by reference herein in its entirety,
including all appendices, for all purposes. COI is applicable for
CCTs from about 3300K to about 5500K, and is preferably of a value
less than about 3.3. If a light source's output around 660 nm is
too low a patient's skin color may appear darker and may be falsely
diagnosed as cyanosed. If a light source's output at 660 nm is too
high, it may mask any cyanosis, and it may not be diagnosed when it
is present. COI is a dimensionless number and is calculated from
the spectral power distribution of the light source. The COI value
is calculated by calculating the color difference between blood
viewed under the test light source and viewed under the reference
lamp (a 4000 K Planckian source) for 50% and 100% oxygen saturation
and averaging the results. The lower the value of COI, the smaller
the shift in color appearance results under illumination by the
source under consideration.
[0041] The ability of a light source to accurately reproduce color
in illuminated objects can be characterized by the Television
Lighting Consistency Index ("TLCI-2012" or "TLCI") value Qa, as
described fully in EBU Tech 3355, Method for the Assessment of the
Colorimetric Properties of Luminaires, European Broadcasting Union
("EBU"), Geneva, Switzerland (2014), and EBU Tech 3355-s1, An
Introduction to Spectroradiometry, which are incorporated by
reference herein in their entirety, including all appendices, for
all purposes. The TLCI compares the test light source to a
reference luminaire, which is specified to be one whose
chromaticity falls on either the Planckian or Daylight locus and
having a color temperature which is that of the CCT of the test
light source. If the CCT is less than 3400 K, then a Planckian
radiator is assumed. If the CCT is greater than 5000 K, then a
Daylight radiator is assumed. If the CCT lies between 3400 K and
5000 K, then a mixed illuminant is assumed, being a linear
interpolation between Planckian at 3400 K and Daylight at 5000 K.
Therefore, it is necessary to calculate spectral power
distributions for both Planckian and Daylight radiators. The
mathematics for both operations is known in the art and is
described more fully in CIE Technical Report 15:2004, Colorimetry
3.sup.rd ed., International Commission on Illumination (2004),
which is incorporated herein in its entirety for all purposes.
[0042] In some exemplary implementations, the present disclosure
provides semiconductor light emitting devices 100 that include a
plurality of LED strings, with each LED string having a recipient
luminophoric medium that comprises a luminescent material. The
LED(s) in each string and the luminophoric medium in each string
together emit an unsaturated light having a color point within a
color range in the 1931 CIE chromaticity diagram. A "color range"
in the 1931 CIE chromaticity diagram refers to a bounded area
defining a group of color coordinates (ccx, ccy).
[0043] In some implementations, four LED strings
(101A/101B/101C/101D) are present in a device 100. One or more of
the LED strings can have recipient luminophoric mediums
(102A/102B/102C/102D). In some implementations, one or more of the
luminophoric mediums can be omitted. In certain implementations,
the fourth luminophoric medium 102D can be omitted. A first LED
string 101A and a first luminophoric medium 102A together can emit
a first light having a first color point within a blue color range.
The combination of the first LED string 101A and the first
luminophoric medium 102A are also referred to herein as a "blue
channel." A second LED string 101B and a second luminophoric medium
102B together can emit a second light having a second color point
within a red color range. The combination of the second LED string
101A and the second luminophoric medium 102A are also referred to
herein as a "red channel." A third LED string 101C and a third
luminophoric medium 102C together can emit a third light having a
third color point within a green color range. The combination of
the third LED string 101C and the third luminophoric medium 102C
are also referred to herein as a "green channel." A fourth LED
string 101D can be provided for functional performance for
capability other than white light generation, or can provide an
additional channel within the visible light spectrum to contribute
to white light generation.
[0044] The first, second, third, and fourth LED strings
101A/101B/101C/101D can be provided with independently applied
on-state drive currents in order to tune the intensity of the
first, second, third, and fourth unsaturated light produced by each
string and luminophoric medium together. By varying the drive
currents in a controlled manner, the color coordinate (ccx, ccy) of
the total light that is emitted from the device 100 can be tuned.
In some implementations, the device 100 can provide light at
substantially the same color coordinate with different spectral
power distribution profiles, which can result in different light
characteristics at the same CCT. In some implementations, white
light can be generated in modes that only produce light from two or
three of the LED strings. In one implementation, white light is
generated using only the first, second, and third LED strings, i.e.
the blue, red, and green channels. In another implementation, white
light is generated using only the first, second, third, and fourth
LED strings, i.e., the blue, red, and green channels, and an
additional channel. In some implementations, only two of the LED
strings are producing light during the generation of white light,
as the other two LED strings are not necessary to generate white
light at the desired color point with the desired color rendering
performance.
[0045] FIGS. 4-6 depict suitable color ranges for some
implementations of the disclosure. FIG. 4A depicts a blue color
range 301A defined by a line connecting the ccx, ccy color
coordinates of the infinity point of the Planckian locus (0.242,
0.24) and (0.12, 0.068), the Planckian locus from 4000K and
infinite CCT, the constant CCT line of 4000K, the line of purples,
and the spectral locus. FIG. 4B depicts a red color range 302A
defined by the spectral locus between the constant CCT line of
1600K and the line of purples, the line of purples, a line
connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47,
0.28), and the constant CCT line of 1600K. FIG. 4C depicts a green
color range 303A defined by the constant CCT line of 6700K, the
Planckian locus, and the spectral locus. It should be understood
that any gaps or openings in the described boundaries for the color
ranges 301A, 302A, 303A should be closed with straight lines to
connect adjacent endpoints in order to define a closed boundary for
each color range.
[0046] In some implementations, suitable color ranges can be
narrower than those described above. FIG. 5 depicts some suitable
color ranges for some implementations of the disclosure. A blue
color range 301B can be defined by a 60-step MacAdam ellipse at a
CCT of 20000K, 40 points below the Planckian locus. A red color
range 302B can be defined by a 20-step MacAdam ellipse at a CCT of
1200K, 20 points below the Planckian locus. A green color range
303B shown in FIG. 4D can be defined by a 60-step MacAdam ellipse
centered approximately 65 points above the Planckian locus at
4500K, the Planckian locus, and the constant CCT line of 6700K.
FIG. 6 depicts some further color ranges suitable for some
implementations of the disclosure. A blue color range 301C is
defined by a polygonal region on the 1931 CIE Chromaticity Diagram
defined by the following ccx, ccy color coordinates: (0.22, 0.14),
(0.19, 0.17), (0.26, 0.26), (0.28, 0.23). A red color range 302C is
defined by a polygonal region on the 1931 CIE Chromaticity Diagram
defined by the following ccx, ccy color coordinates: (0.53, 0.41),
(0.59, 0.39), (0.63, 0.29), (0.58, 0.30).
[0047] In some implementations, the LEDs in the first, second,
third and fourth LED strings can be LEDs with peak emission
wavelengths at or below about 535 nm. In some implementations, the
LEDs emit light with peak emission wavelengths between about 360 nm
and about 535 nm. In some implementations, the LEDs in the first,
second, third and fourth LED strings can be formed from InGaN
semiconductor materials. In some preferred implementations, the
first, second, and third LED strings can have LEDs having a peak
wavelength between about 405 nm and about 485 nm. The LEDs used in
the first, second, third, and fourth LED strings may have
full-width half-maximum wavelength ranges of between about 10 nm
and about 30 nm. In some preferred implementations, the first,
second, and third LED strings can include one or more LUXEON Z
Color Line royal blue LEDs (product code LXZ1-PR01) of color bin
codes 3, 4, 5, or 6 or one or more LUXEON Z Color Line blue LEDs
(LXZ1-PB01) of color bin code 1 or 2 (Lumileds Holding B.V.,
Amsterdam, Netherlands). Similar LEDs from other manufacturers such
as OSRAM GmbH and Cree, Inc. could also be used, provided they have
peak emission and full-width half-maximum wavelengths of the
appropriate values.
[0048] In implementations utilizing LEDs that emit substantially
saturated light at wavelengths between about 360 nm and about 535
nm, the device 100 can include suitable recipient luminophoric
mediums for each LED in order to produce light having color points
within the suitable blue color ranges 301A-C, red color ranges
302A-C, and green color ranges 303A-B described herein. The light
emitted by each LED string, i.e., the light emitted from the LED(s)
and associated recipient luminophoric medium together, can have a
spectral power distribution ("SPD") having spectral power with
ratios of power across the visible wavelength spectrum from about
380 nm to about 780 nm. While not wishing to be bound by any
particular theory, it is speculated that the use of such LEDs in
combination with recipient luminophoric mediums to create
unsaturated light within the suitable color ranges 301A-C, 302A-C,
and 303A-B, provides for improved color rendering performance for
white light across a predetermined range of CCTs from a single
device 100. Some suitable ranges for spectral power distribution
ratios of the light emitted by the four LED strings
(101A/101B/101C) and recipient luminophoric mediums
(102A/102B/102C), if provided, together are shown in Tables 1, 2,
3, and 4. The Tables 1, 2, 3, and 4 show the ratios of spectral
power within wavelength ranges, with an arbitrary reference
wavelength range selected for each color range and normalized to a
value of 100.0. Tables 1 and 2 show suitable minimum and maximum
values for the spectral intensities within various ranges relative
to the normalized range with a value of 100.0, for the color points
within the blue, green, and red color ranges. While not wishing to
be bound by any particular theory, it is speculated that because
the spectral power distributions for generated light with color
points within the red, blue, and green color ranges contains higher
spectral intensity across visible wavelengths as compared to
lighting apparatuses and methods that utilize more saturated
colors, this allows for improved color rendering for test colors
other than R1-R8.
TABLE-US-00001 TABLE 1 Spectral Power Distribution for Wavelength
Ranges (nm) 380- 420- 461- 501- 541- 581- 621- 661- 701- 741- 420
460 500 540 580 620 660 700 741 780 Blue 0.3 100.0 20.9 15.2 25.3
26.3 15.4 5.9 2.3 1.0 minimum Blue 8.1 100.0 196.1 35.6 40.5 70.0
80.2 20.4 7.8 2.3 maximum Red 0.0 2.1 2.0 1.4 8.7 48.5 100.0 1.8
0.5 0.3 minimum Red 14.8 15. 6.7 12.2 20.5 102.8 100.0 74.3 29.5
9.0 maximum Green 0.2 100.0 112.7 306.2 395.1 318.2 245.0 138.8
52.6 15.9 minimum Green 130.6 100.0 534.7 6748.6 10704.1 13855.8
15041.2 9802.9 3778.6 1127.3 maximum
TABLE-US-00002 TABLE 2 Spectral Power Distribution for Wavelength
Ranges (nm) 380-500 501-600 601-700 701-780 Blue minimum 100.0 27.0
24.8 1.1 Blue maximum 100.0 65.1 46.4 6.8 Red minimum 17.4 8.9
100.0 1.1 Red maximum 3.3 24.8 100.0 18.1 Green minimum 100.0 279.0
170.8 14.6 Green maximum 100.0 2313.6 2211.6 270.7
[0049] In some implementations, the green channel can have certain
spectral power distributions. Table 3 shows the ratios of spectral
power within wavelength ranges, with an arbitrary reference
wavelength range selected for the green color range and normalized
to a value of 100.0, for a green channel that may be used in some
implementations of the disclosure. The exemplary Green Channel 1
has a ccx, ccy color coordinate of (0.3263, 0.5403) and a dominant
wavelength of approximately 554 nm. The exemplary Green Channel 2
has a ccx, ccy color coordinate of (0.4482, 0.5258) and a dominant
wavelength of approximately 573 nm. The exemplary Green Channel 3
has a ccx, ccy color coordinate of (0.5108, 0.4708) and a dominant
wavelength of approximately 582 nm. In certain implementations, the
green channel can have a spectral power distribution with spectral
power in one or more of the wavelength ranges other than the
reference wavelength range increased or decreased within 30%
greater or less, within 20% greater or less, within 10% greater or
less, or within 5% greater or less than the values shown in Table
3.
[0050] In some implementations, the red channel can have certain
spectral power distributions. Tables 3 and 4 show the ratios of
spectral power within wavelength ranges, with an arbitrary
reference wavelength range selected for the red color range and
normalized to a value of 100.0, for a red channel that may be used
in some implementations of the disclosure. The exemplary Red
Channel 1 has a ccx, ccy color coordinate of (0.5735, 0.3007) and a
dominant wavelength of approximately 641 nm. The exemplary Red
Channel 2 has a ccx, ccy color coordinate of (0.5842, 0.3112) and a
dominant wavelength of approximately 625 nm. In certain
implementations, the red channel can have a spectral power
distribution with spectral power in one or more of the wavelength
ranges other than the reference wavelength range increased or
decreased within 30% greater or less, within 20% greater or less,
within 10% greater or less, or within 5% greater or less than the
values shown in Tables 3 and 4.
[0051] In some implementations, the blue channel can have certain
spectral power distributions. Tables 3 and 4 show the ratios of
spectral power within wavelength ranges, with an arbitrary
reference wavelength range selected for the blue color range and
normalized to a value of 100.0, for a blue channel that may be used
in some implementations of the disclosure. The exemplary Blue
Channel 1 has a ccx, ccy color coordinate of (0.252, 0.223) and a
dominant wavelength of approximately 470 nm. Exemplary Blue Channel
2 has a ccx, ccy color coordinate of (0.2625, 0.1763) and a
dominant wavelength of approximately 381 nm. In certain
implementations, the blue channel can have a spectral power
distribution with spectral power in one or more of the wavelength
ranges other than the reference wavelength range increased or
decreased within 30% greater or less, within 20% greater or less,
within 10% greater or less, or within 5% greater or less than the
values shown in Tables 3 and 4.
TABLE-US-00003 TABLE 3 Exemplary Spectral Power Distribution for
Wavelength Ranges (nm) Color 380- 401- 421- 441- 461- 481- 501-
521- 541- 561- 581- 601- Channels 400 420 440 460 480 500 520 540
560 580 600 620 Blue 0.3 0.7 11.4 100 70.7 27.9 23.5 25.1 24.6 22.3
21.0 21.2 Channel 1 Red 0.1 0.1 0.7 4.5 4.9 3.5 6.7 11.6 17.6 30.0
48.9 67.9 Channel 1 Green 0.6 0.5 2.4 14.0 21.6 63.4 97.1 99.5
100.0 89.1 71.9 57.8 Channel 1 Green 0.4 1.5 1.6 0.5 1.0 10.0 53.1
93.5 100.0 93.5 84.5 77.3 Channel 2 Green 0.0 0.0 0.1 1.2 2.3 3.3
23.1 51.6 64.5 67.5 73.5 89.3 Channel 3 Exemplary Spectral Power
Distribution for Wavelength Ranges (nm) Color 621- 641- 661- 681-
701- 721- 741- 761- 781- Channels 640 660 680 700 720 740 760 780
800 Blue 20.9 18.1 13.4 8.7 5.2 3.1 1.9 1.3 0.0 Channel 1 Red 93.5
100.0 66.0 33.7 16.5 7.6 3.2 1.5 0.0 Channel 1 Green 54.1 48.6 31.0
16.1 8.1 3.9 1.8 1.1 0.0 Channel 1 Green 72.0 62.7 47.5 31.7 19.2
11.0 6.0 3.1 0.0 Channel 2 Green 100.0 91.3 70.0 47.1 28.8 16.6 9.1
4.8 0.0 Channel 3
TABLE-US-00004 TABLE 4 Spectral Power Distribution for Wavelength
Ranges (nm) Exemplary Color Channels 380-420 420-460 461-500
501-540 541-580 581-620 621-660 661-700 701-741 741-780 Blue
Channel 0.4 100.0 20.9 15.2 25.3 26.3 25.1 13.9 5.2 1.6 2 Red
Channel 9.2 8.6 1.0 4.6 11.0 46.5 100.0 75.5 29.8 8.5 2
[0052] In some implementations, the semiconductor light emitting
devices of the present disclosure can include first, second, and
third LED strings 101A/101B/101C that generate the red, blue, and
green channels described elsewhere herein in combination with
luminophoric mediums 102A/102B/102C. In certain implementations,
the first, second, and third LED strings can provide broad-range,
spectrally rich high CRI white light, which can enable the use of
an application-specific fourth LED string. The application-specific
fourth LED string can contribute to the color-rendering of white
light generated by the other three LED strings, or the fourth LED
string can be operated in a separate mode when the other three LED
strings are not generating light, or the fourth LED string can be
operated simultaneously with the other three LED strings but can
generate wavelengths unrelated to white light. In some
implementations, a fourth LED string can be provide in the
semiconductor light emitting devices of the disclosure, with the
fourth LED string including diodes that can have emissions driven
by the same electronic circuitry and control systems as the diodes
of the first, second, and third LED strings. In certain
implementations, the semiconductor light emitting devices can
further include a fourth LED string that comprises one or more of
380-420 nm violet saturated LEDs, 200-280 nm UVC saturated LEDs,
850-940 nm near-IR saturated LEDs, 580-620 nm amber-orange/red
saturated LEDs, 460-490 nm long-blue saturated LEDs, or any other
type of LEDs with the desired application-specific wavelength
emissions. In certain implementations, each diode in the fourth LED
string can be provided with an associated luminophoric medium so
that a desired combined emission of unsaturated light can be
provided.
[0053] Blends of luminescent materials can be used in luminophoric
mediums (102A/102B/102C/102D) to create luminophoric mediums having
the desired saturated color points when excited by their respective
LED strings (101A/101B/101C/101D) including luminescent materials
such as those disclosed in co-pending application PCT/US2016/015318
filed Jan. 28, 2016, entitled "Compositions for LED Light
Conversions", the entirety of which is hereby incorporated by this
reference as if fully set forth herein. Traditionally, a desired
combined output light can be generated along a tie line between the
LED string output light color point and the saturated color point
of the associated recipient luminophoric medium by utilizing
different ratios of total luminescent material to the encapsulant
material in which it is incorporated. Increasing the amount of
luminescent material in the optical path will shift the output
light color point towards the saturated color point of the
luminophoric medium. In some instances, the desired saturated color
point of a recipient luminophoric medium can be achieved by
blending two or more luminescent materials in a ratio. The
appropriate ratio to achieve the desired saturated color point can
be determined via methods known in the art. Generally speaking, any
blend of luminescent materials can be treated as if it were a
single luminescent material, thus the ratio of luminescent
materials in the blend can be adjusted to continue to meet a target
CIE value for LED strings having different peak emission
wavelengths. Luminescent materials can be tuned for the desired
excitation in response to the selected LEDs used in the LED strings
(101A/101B/101C/101D), which may have different peak emission
wavelengths within the range of from about 360 nm to about 535 nm.
Suitable methods for tuning the response of luminescent materials
are known in the art and may include altering the concentrations of
dopants within a phosphor, for example. In some implementations of
the present disclosure, luminophoric mediums can be provided with
combinations of two types of luminescent materials. The first type
of luminescent material emits light at a peak emission between
about 515 nm and about 590 nm in response to the associated LED
string emission. The second type of luminescent material emits at a
peak emission between about 590 nm and about 700 nm in response to
the associated LED string emission. In some instances, the
luminophoric mediums disclosed herein can be formed from a
combination of at least one luminescent material of the first and
second types described in this paragraph. In implementations, the
luminescent materials of the first type can emit light at a peak
emission at about 515 nm, 525 nm, 530 nm, 535 nm, 540 nm, 545 nm,
550 nm, 555 nm, 560 nm, 565 nm, 570 nm, 575 nm, 580 nm, 585 nm, or
590 nm in response to the associated LED string emission. In
preferred implementations, the luminescent materials of the first
type can emit light at a peak emission between about 520 nm to
about 555 nm. In implementations, the luminescent materials of the
second type can emit light at a peak emission at about 590 nm,
about 595 nm, 600 nm, 605 nm, 610 nm, 615 nm, 620 nm, 625 nm, 630
nm, 635 nm, 640 nm, 645 nm, 650 nm, 655 nm, 670 nm, 675 nm, 680 nm,
685 nm, 690 nm, 695 nm, or 700 nm in response to the associated LED
string emission. In preferred implementations, the luminescent
materials of the first type can emit light at a peak emission
between about 600 nm to about 670 nm. Some exemplary luminescent
materials of the first and second type are disclosed elsewhere
herein and referred to as Compositions A-F. Table 5 shows aspects
of some exemplar luminescent materials and properties:
TABLE-US-00005 TABLE 5 Emission Peak Density Emission FWHM Range
FWHM Designator Exemplary Material(s) (g/mL) Peak (nm) (nm) (nm)
Range (nm) Composition Luag: Cerium doped 6.73 535 95 530-540
90-100 ''A'' lutetium aluminum garnet (Lu.sub.3Al.sub.5O.sub.12)
Composition Yag: Cerium doped yttrium 4.7 550 110 545-555 105-115
''B'' aluminum garnet (Y.sub.3Al.sub.5O.sub.12) Composition a 650
nm-peak wavelength 3.1 650 90 645-655 85-95 ''C'' emission
phosphor: Europium doped calcium aluminum silica nitride
(CaAlSiN.sub.3) Composition a 525 nm-peak wavelength ''D'' emission
phosphor: GBAM: 3.1 525 60 520-530 55-65 BaMgAl.sub.10O.sub.17:Eu
Composition a 630 nm-peak wavelength 5.1 630 40 625-635 35-45 ''E''
emission quantum dot: any semiconductor quantum dot material of
appropriate size for desired emission wavelengths Composition a 610
nm-peak wavelength 5.1 610 40 605-615 35-45 ''F'' emission quantum
dot: any semiconductor quantum dot material of appropriate size for
desired emission wavelengths
[0054] Blends of Compositions A-F can be used in luminophoric
mediums (102A/102B/102C/102D) to create luminophoric mediums having
the desired saturated color points when excited by their respective
LED strings (101A/101B/101C/101D). In some implementations, one or
more blends of one or more of Compositions A-F can be used to
produce luminophoric mediums (102A/102B/102C/102D). In some
preferred implementations, one or more of Compositions A, B, and D
and one or more of Compositions C, E, and F can be combined to
produce luminophoric mediums (102A/102B/102C/102D). In some
preferred implementations, the encapsulant for luminophoric mediums
(102A/102B/102C/102D) comprises a matrix material having density of
about 1.1 mg/mm.sup.3 and refractive index of about 1.545 or from
about 1.4 to about 1.6. In some implementations, Composition A can
have a refractive index of about 1.82 and a particle size from
about 18 micrometers to about 40 micrometers. In some
implementations, Composition B can have a refractive index of about
1.84 and a particle size from about 13 micrometers to about 30
micrometers. In some implementations, Composition C can have a
refractive index of about 1.8 and a particle size from about 10
micrometers to about 15 micrometers. In some implementations,
Composition D can have a refractive index of about 1.8 and a
particle size from about 10 micrometers to about 15 micrometers.
Suitable phosphor materials for Compositions A, B, C, and D are
commercially available from phosphor manufacturers such as
Mitsubishi Chemical Holdings Corporation (Tokyo, Japan), Intematix
Corporation (Fremont, Calif.), EMD Performance Materials of Merck
KGaA (Darmstadt, Germany), and PhosphorTech Corporation (Kennesaw,
Ga.).
[0055] In some applications, it can be desirable to provide white
light having spectral power in the violet or ultraviolet spectrum
between 380 nm-420 nm. For example, some commercial textiles are
provided with brightening agents that are excited by violet or
ultraviolet wavelengths in order to provide products that appear
whiter or more vibrant. Further, some detergents are provided with
such brightening agents, such that clothing may appear duller under
light that lacks violet or ultraviolet wavelengths to induce
excitation and the desired color appearance to an observer.
Accordingly, in some implementations of the disclosure, devices are
provided having one or more LEDs in the violet or ultraviolet
spectrum in order to contribute those wavelengths to the final
spectrum of generated white light. This can produce desirable
effects in some settings, such as making clothing or other textiles
appear more white or vibrant.
[0056] In some aspects, the present disclosure provides
semiconductor light emitting devices capable to producing tunable
white light through a range of CCT values. In some implementations,
devices of the present disclosure can output white light at color
points along a predetermined path within a 7-step MacAdam ellipse
around any point on the black body locus having a correlated color
temperature between 1800K and 10000K. In some implementations, the
semiconductor light emitting devices can comprise first, second,
and third LED strings, with each LED string comprising one or more
LEDs having an associated luminophoric medium, wherein the first,
second, and third LED strings together with their associated
luminophoric mediums can comprise red, blue, and green channels
respectively, producing first, second, and third unsaturated color
points within red, blue, and green regions on the 1931 CIE
Chromaticity diagram, respectively, and a control circuit can be
configured to adjust a fourth color point of a fourth unsaturated
light that results from a combination of the first, second, and
third unsaturated light, with the fourth color point falls within a
7-step MacAdam ellipse around any point on the black body locus
having a correlated color temperature between 1800K and 10000K. In
some implementations the device further comprises a fourth LED
string comprising one or more LEDs. In some implementations the
LEDs of the fourth LED string comprise a type of LED selected from
380-420 nm violet saturated LEDs, 200-280 nm UVC saturated LEDs,
850-940 nm near-IR saturated LEDs, 580-620 nm amber-orange/red
saturated LEDs, and 460-490 nm long-blue saturated LEDs. In certain
implementations, the LEDs of the fourth LED string comprise 380-420
nm violet saturated LEDs. In other implementations, the LEDs of the
fourth LED string comprise 200-280 nm UVC saturated LEDs. In
further implementations, the LEDs of the fourth LED string comprise
850-940 nm near-IR saturated LEDs. In yet further implementations,
the LEDs of the fourth LED string comprise 580-620 nm
amber-orange/red saturated LEDs. In certain implementations, the
control circuit is further configured to adjust a sixth color point
of a sixth unsaturated light that results from a combination of the
first, second, and third unsaturated light and a fifth saturated
light generated by the fourth LED string, with the sixth color
point falling within a 7-step MacAdam ellipse around any point on
the black body locus having a correlated color temperature between
1800K and 10000K. In some implementations, the control circuit is
configured to provide two operating modes comprise a first
operating mode that generates light only using the blue, red, and
green channels and a second operating mode that generates light
using the blue, red, and green channels and the fourth LED string.
In some implementations, the control circuit is configured to
switch between the first operating mode and the second operating
mode to provide the fourth unsaturated light and the sixth
unsaturated light having substantially the same ccx, ccy
coordinates on the 1931 CIE Chromaticity Diagram. In some
implementations, the fourth unsaturated light and the sixth
unsaturated light have color points within about 1.0 standard
deviations of color matching (SDCM). In some implementations, the
fourth unsaturated light and the sixth unsaturated light have color
points within about 0.5 standard deviations of color matching
(SDCM). In certain implementations, the sixth unsaturated light has
improved color-rendering characteristics in comparison to the
fourth unsaturated light. In certain implementations, the improved
color-rendering characteristics of the sixth unsaturated light in
comparison to the fourth unsaturated light is one or more of Ra,
R9, Rf, and Rg. In some implementations, the devices can be
configured to generate the fourth or sixth unsaturated light
corresponding to a plurality of points along a predefined path with
the light generated at each point having light with BLH factor less
than 0.05 .mu.W/cm.sup.2/lux. In some implementations, the devices
can be configured to generate the fourth or sixth unsaturated light
corresponding to a plurality of points along a predefined path with
the light generated at each point having light with one or more of
BLH factor less than or equal to about 0.01 along points with
correlated color temperature below about 2100K, BLH factor less
than or equal to about 0.015 along points with correlated color
temperature below about 2400K, BLH factor less than or equal to
about 0.025 along points with correlated color temperature below
about 3000K, BLH factor less than or equal to about 0.05 along
points with correlated color temperature below about 4000K, and BLH
factor less than or equal to about 0.060 along points with
correlated color temperature below about 6500K. In some
implementations, the devices can be configured to generate the
fourth or sixth unsaturated light corresponding to a plurality of
points along a predefined path with the light generated at each
point having light with the ratio of the EML to the BLH factor
being greater than or equal to about 15, greater than or equal to
about 20, greater than or equal to about 21, greater than or equal
to about 22, greater than or equal to about 23, greater than or
equal to about 24, greater than or equal to about 25, greater than
or equal to about 26, greater than or equal to about 27, greater
than or equal to about 28, greater than or equal to about 29,
greater than or equal to about 30, greater than or equal to about
35, or greater than or equal to about 40. Providing a higher ratio
of the EML to the BLH factor can be advantageous to provide light
that provides desired biological impacts but does not have as much
potential for photochemical induced injuries to the retina or
skin.
[0057] In some aspects, the present disclosure provides methods of
generating white light, the methods comprising providing first,
second, and third LED strings, with each LED string comprising one
or more LEDs having an associated luminophoric medium, providing a
fourth LED string, wherein the first, second, and third LED strings
together with their associated luminophoric mediums comprise red,
blue, and green channels respectively, producing first, second, and
third unsaturated light with color points within red, blue, and
green regions on the 1931 CIE Chromaticity diagram, respectively,
providing a control circuit configured to adjust a fourth color
point of a fourth unsaturated light that results from a combination
of the first, second, and third, unsaturated light, with the fourth
color point falls within a 7-step MacAdam ellipse around any point
on the black body locus having a correlated color temperature
between 1800K and 10000K, wherein the control circuit is further
configured to adjust a sixth color point of a sixth unsaturated
light that results from a combination of the first, second, and
third unsaturated light and a fifth saturated light from the fourth
LED string, generating light in a first operating mode with two or
more of the first, second, and third unsaturated light by combining
the two or more generated unsaturated lights to create the fourth
unsaturated light, and generating light in a second operating mode
with two or more of the first, second, and third unsaturated light
and the fifth saturated light by combining the two or more
generated unsaturated/saturated light to create the sixth
unsaturated light. In some implementations, the LEDs of the fourth
LED string comprise a type of LED selected from 380-420 nm violet
saturated LEDs, 200-280 nm UVC saturated LEDs, 850-940 nm near-IR
saturated LEDs, 580-620 nm amber-orange/red saturated LEDs, and
460-490 nm long-blue saturated LEDs. In some implementations, the
LEDs of the fourth LED string comprise 380-420 nm violet saturated
LEDs. In some implementations, the LEDs of the fourth LED string
comprise 200-280 nm UVC saturated LEDs. In some implementations,
the LEDs of the fourth LED string comprise 850-940 nm near-IR
saturated LEDs. In some implementations, the LEDs of the fourth LED
string comprise 580-620 nm amber-orange/red saturated LEDs. In some
implementations, the control circuit is configured to switch
between the first operating mode and the second operating mode to
provide the fourth unsaturated light and the sixth unsaturated
light having substantially the same ccx, ccy coordinates on the
1931 CIE Chromaticity Diagram. In some implementations, the fourth
unsaturated light and the sixth unsaturated light have color points
within about 1.0 standard deviations of color matching (SDCM). In
some implementations, the fourth unsaturated light and the sixth
unsaturated light have color points within about 0.5 standard
deviations of color matching (SDCM). In some implementations, the
sixth unsaturated light has improved color-rendering performance in
comparison to the fourth unsaturated light in one or more of Ra,
R9, Rf, and Rg.
EXAMPLES
General Simulation Method.
[0058] Devices having four LED strings with particular color points
were simulated. For each device, LED strings and recipient
luminophoric mediums with particular emissions were selected, and
then white light rendering capabilities were calculated for a
select number of representative points on or near the Planckian
locus between about 1800K and 10000K. Ra, R9, R13, R15, LER, Rf,
Rg, CLA, CS, EML, BLH factor, CAF, CER, COI, and circadian
performance values were calculated at each representative
point.
[0059] The calculations were performed with Scilab (Scilab
Enterprises, Versailles, France), LightTools (Synopsis, Inc.,
Mountain View, Calif.), and custom software created using Python
(Python Software Foundation, Beaverton, Oreg.). Each LED string was
simulated with an LED emission spectrum and excitation and emission
spectra of luminophoric medium(s). For luminophoric mediums
comprising phosphors, the simulations also included the absorption
spectrum and particle size of phosphor particles. The LED strings
generating combined emissions within blue, green, and red color
regions were prepared using spectra of a LUXEON Z Color Line royal
blue LED (product code LXZ1-PR01) of color bin codes 3, 4, 5, or 6
or a LUXEON Z Color Line blue LED (LXZ1-PB01) of color bin code 1
or 2 (Lumileds Holding B.V., Amsterdam, Netherlands). Similar LEDs
from other manufacturers such as OSRAM GmbH and Cree, Inc. could
also be used.
[0060] The emission, excitation and absorption curves are available
from commercially available phosphor manufacturers such as
Mitsubishi Chemical Holdings Corporation (Tokyo, Japan), Intematix
Corporation (Fremont, Calif.), EMD Performance Materials of Merck
KGaA (Darmstadt, Germany), and PhosphorTech Corporation (Kennesaw,
Ga.). The luminophoric mediums used in the LED strings were
combinations of one or more of Compositions A, B, and D and one or
more of Compositions C, E, and F as described more fully elsewhere
herein. Those of skill in the art appreciate that various
combinations of LEDs and luminescent blends can be combined to
generate combined emissions with desired color points on the 1931
CIE chromaticity diagram and the desired spectral power
distributions.
Example 1
[0061] A semiconductor light emitting device was simulated having
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3. A fourth LED string is a violet LED having a
peak emission wavelength of approximately 380 nm.
[0062] FIGS. 7A-7F shows light-rendering characteristics of the
device for a representative selection of white light color points
near the Planckian locus. FIGS. 7A-7B show data for white light
color points generated using only the first, second, and third LED
strings. FIGS. 7C-7D show data for white light color points
generated using all four LED strings. FIGS. 7E-7F show performance
comparison between white light color points generated at similar
approximate CCT values under operating modes using three or four
LED strings.
Example 2
[0063] A semiconductor light emitting device was simulated having
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3. A fourth LED string is a violet LED having a
peak emission wavelength of approximately 400 nm.
[0064] FIGS. 8A-8F shows light-rendering characteristics of the
device for a representative selection of white light color points
near the Planckian locus. FIGS. 8A-8B show data for white light
color points generated using only the first, second, and third LED
strings. FIGS. 8C-8D show data for white light color points
generated using all four LED strings. FIGS. 8E-8F show performance
comparison between white light color points generated at similar
approximate CCT values under operating modes using three or four
LED strings.
Example 3
[0065] A semiconductor light emitting device was simulated having
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3. A fourth LED string is a violet LED having a
peak emission wavelength of approximately 420 nm.
[0066] FIGS. 9A-9F shows light-rendering characteristics of the
device for a representative selection of white light color points
near the Planckian locus. FIGS. 9A-9B show data for white light
color points generated using only the first, second, and third LED
strings. FIGS. 9C-9D show data for white light color points
generated using all four LED strings. FIGS. 9E-9F show performance
comparison between white light color points generated at similar
approximate CCT values under operating modes using three or four
LED strings.
Example 4
[0067] A semiconductor light emitting device can be formed from
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3.
[0068] A fourth LED string can be a LED string designed to provide
functional performance for capability other than white light
generation. The fourth LED string can be a 200-280 nm UVC saturated
LED string to provide sterilization capabilities. This generated
radiation is non-visible, and may be used in conjunction with the
other visible channels or as an alternative mode for hospital rooms
or other care facilities. Sensors or other data inputs can verify
that the illuminated area is unoccupied during a sterilization
process using the UVC light.
Example 5
[0069] A semiconductor light emitting device can be formed from
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3.
[0070] A fourth LED string can be a LED string designed to provide
functional performance for capability other than white light
generation. The fourth LED string can be an 850-940 nm near IR
saturated LED to provide "night vision" capabilities for security
cameras. The near IR radiation is non-visible, and may be used in
conjunction with the other visible channels or as an alternative
mode for lights-out observation of secured facilities with IR
cameras.
Example 6
[0071] A semiconductor light emitting device can be formed from
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3.
[0072] A fourth LED string can be a LED string designed to provide
functional performance for capability other than white light
generation. The fourth LED string can be a 580-620 nm
amber-orange/red saturated LED to provide a "night light" mode for
assisted care facilities, hospital bathrooms, or nurseries. By not
stimulating any of the Circadian-active wavelengths, amber or
red/orange light is less likely to disrupt sleep levels. These
wavelengths are close enough to the peak eye response to allow for
reasonable visual acuity for tasks like getting to/from a bathroom,
or changing a baby's diaper. The amber-orange/red color can be used
in conjunction with the other three channels or may be used in an
alternative illumination mode.
Example 7
[0073] A semiconductor light emitting device can be formed from
four LED strings. A first LED string is driven by a blue LED having
peak emission wavelength of approximately 450 nm to approximately
455 nm, utilizes a recipient luminophoric medium, and generates a
combined emission of a blue channel having the characteristics of
Blue Channel 1 as described above and shown in Table 3. A second
LED string is driven by a blue LED having peak emission wavelength
of approximately 450 nm to approximately 455 nm, utilizes a
recipient luminophoric medium, and generates a combined emission of
a red channel having the characteristics of Red Channel 1 as
described above and shown in Table 3. A third LED string is driven
by a blue LED having peak emission wavelength of approximately 450
nm to approximately 455 nm, utilizes a recipient luminophoric
medium, and generates a combined emission of a green color channel
having the characteristics of Green Channel 1 as described above
and shown in Table 3.
[0074] A fourth LED string can be a LED string designed to provide
functional performance for capability other than white light
generation. The fourth LED string can be a 460-490 nm long-blue
saturated LED to provide a bilirubin-therapy mode to a general
illumination system. This eliminates the need for a specific lamp
for the purpose in addition to general-purpose white lighting. This
would allow for physicians to evaluate the infant in situ, under
high color quality white light, and return the infant to 460-490 nm
phototherapy without having to move the infant from one location to
another. The saturated long-blue channel could provide color
rendering benefits when used in conjunction with the other three
channels in a white light mode.
[0075] Those of ordinary skill in the art will appreciate that a
variety of materials can be used in the manufacturing of the
components in the devices and systems disclosed herein. Any
suitable structure and/or material can be used for the various
features described herein, and a skilled artisan will be able to
select an appropriate structures and materials based on various
considerations, including the intended use of the systems disclosed
herein, the intended arena within which they will be used, and the
equipment and/or accessories with which they are intended to be
used, among other considerations. Conventional polymeric,
metal-polymer composites, ceramics, and metal materials are
suitable for use in the various components. Materials hereinafter
discovered and/or developed that are determined to be suitable for
use in the features and elements described herein would also be
considered acceptable.
[0076] When ranges are used herein for physical properties, such as
molecular weight, or chemical properties, such as chemical
formulae, all combinations, and subcombinations of ranges for
specific exemplar therein are intended to be included.
[0077] The disclosures of each patent, patent application, and
publication cited or described in this document are hereby
incorporated herein by reference, in its entirety.
[0078] Those of ordinary skill in the art will appreciate that
numerous changes and modifications can be made to the exemplars of
the disclosure and that such changes and modifications can be made
without departing from the spirit of the disclosure. It is,
therefore, intended that the appended claims cover all such
equivalent variations as fall within the true spirit and scope of
the disclosure.
* * * * *