U.S. patent application number 14/051616 was filed with the patent office on 2014-02-13 for solid state light with optical guide and integrated thermal guide.
This patent application is currently assigned to 3M INNOVATIVE PROPERTIES COMPANY. The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to RAYMOND P. JOHNSTON, MARTIN KRISTOFFERSEN, MICHAEL A. MEIS.
Application Number | 20140043824 14/051616 |
Document ID | / |
Family ID | 43534721 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140043824 |
Kind Code |
A1 |
JOHNSTON; RAYMOND P. ; et
al. |
February 13, 2014 |
SOLID STATE LIGHT WITH OPTICAL GUIDE AND INTEGRATED THERMAL
GUIDE
Abstract
A solid state light having a solid state light source such as
LEDs, and optical guide, and a thermal guide. The optical guide is
coupled to the light source for receiving and distributing light
from the light source, and the thermal guide is integrated with the
optical guide for providing thermal conduction from the solid state
light source and dissipating heat through convection for cooling
the light.
Inventors: |
JOHNSTON; RAYMOND P.; (LAKE
ELMO, MN) ; MEIS; MICHAEL A.; (STILLWATER, MN)
; KRISTOFFERSEN; MARTIN; (PORSGRUNN, NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Assignee: |
3M INNOVATIVE PROPERTIES
COMPANY
St. Paul
MN
|
Family ID: |
43534721 |
Appl. No.: |
14/051616 |
Filed: |
October 11, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12535203 |
Aug 4, 2009 |
8596825 |
|
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14051616 |
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Current U.S.
Class: |
362/294 |
Current CPC
Class: |
F21Y 2105/00 20130101;
G02B 6/0045 20130101; F21Y 2115/10 20160801; F21Y 2115/15 20160801;
H01L 51/5262 20130101; F21V 29/83 20150115; G02B 6/0095 20130101;
H01L 2251/5361 20130101; F21K 9/61 20160801; F21V 29/673 20150115;
F21K 9/232 20160801; F21V 29/677 20150115; G02B 6/0085 20130101;
F21V 29/773 20150115; H01L 51/529 20130101; F21V 29/51 20150115;
F21V 29/74 20150115; F21V 29/70 20150115 |
Class at
Publication: |
362/294 |
International
Class: |
F21V 29/00 20060101
F21V029/00 |
Claims
1. A light with integrated light and thermal guides, comprising: a
light source; a light guide coupled to the light source for
receiving and distributing light from the light source, wherein the
light is transported within the light guide until the light exits
from a surface of the light guide; and a thermal guide integrated
with the light guide for providing thermal conduction from the
light source for cooling the light, wherein the thermal guide
comprises a solid material capable of conducting heat from the
light source and dissipating the heat, wherein the light guide
comprises a material having a first surface and a second surface
opposite the first surface and an edge between the first and second
surfaces, the light exits from the first or second surface, and the
light with the integrated light and thermal guides provides for air
flow proximate the first and second surfaces, wherein the light
source is located at the edge of the light guide in order to
optically couple the light into the light guide at the edge,
wherein the light includes a light frequency shifting material.
2. The light of claim 1, wherein the light frequency shifting
material comprises a dye.
3. A light with integrated light and thermal guides, comprising: a
light source; a light guide coupled to the light source for
receiving and distributing light from the light source, wherein the
light is transported within the light guide until the light exits
from a surface of the light guide; and a thermal guide integrated
with the light guide for providing thermal conduction from the
light source for cooling the light, wherein the thermal guide
comprises a solid material capable of conducting heat from the
light source and dissipating the heat, wherein the light guide
comprises a material having a first surface and a second surface
opposite the first surface and an edge between the first and second
surfaces, the light exits from the first or second surface, and the
light with the integrated light and thermal guides provides for air
flow proximate the first and second surfaces, wherein the light
source is located at the edge of the light guide in order to
optically couple the light into the light guide at the edge,
wherein the light guide comprises a sheet of material having a
non-planar shape.
4. The light of claim 3, wherein the first or second surface of the
light guide includes light extraction features.
5. The light of claim 4, wherein the light extraction features
comprise a pattern of dots.
6. The light of claim 4, wherein the light extraction features
comprise prisms.
7. The light of claim 4, wherein the light extraction features
comprise lenslets.
8. The light of claim 3, further comprising a reflective layer on
one side of the light guide.
9. A light with integrated light and thermal guides, comprising: a
light source; a light guide comprising a material having a first
surface and a second surface opposite the first surface and an edge
between the first and second surfaces, wherein the second surface
forms an interior volume, the light guide is coupled to the light
source for receiving and distributing light from the light source
through the first or second surface, and the light is transported
within the light guide until the light exits from the first or
second surface of the light guide, wherein the light source is
located at the edge of the light guide in order to optically couple
the light into the light guide at the edge; and a thermal guide at
least partially contained within the interior volume and integrated
with the light guide for providing thermal conduction from the
light source for cooling the light, wherein the thermal guide
comprises a solid material capable of conducting heat from the
light source and dissipating the heat, wherein the light includes a
light frequency shifting material.
10. The light of claim 9, wherein the light frequency shifting
material comprises a dye.
11. A light with integrated light and thermal guides, comprising: a
light source; a light guide comprising a material having a first
surface and a second surface opposite the first surface and an edge
between the first and second surfaces, wherein the second surface
forms an interior volume, the light guide is coupled to the light
source for receiving and distributing light from the light source
through the first or second surface, and the light is transported
within the light guide until the light exits from the first or
second surface of the light guide, wherein the light source is
located at the edge of the light guide in order to optically couple
the light into the light guide at the edge; and a thermal guide at
least partially contained within the interior volume and integrated
with the light guide for providing thermal conduction from the
light source for cooling the light, wherein the thermal guide
comprises a solid material capable of conducting heat from the
light source and dissipating the heat, wherein the light guide
comprises a spherical shape.
12. The light of claim 11, wherein the first or second surface of
the light guide includes light extraction features.
13. The light of claim 12, wherein the light extraction features
comprise a pattern of dots.
14. The light of claim 12, wherein the light extraction features
comprise prisms.
15. The light of claim 12, wherein the light extraction features
comprise lenslets.
16. The light of claim 11, wherein the light guide includes a
plurality of apertures.
Description
BACKGROUND
[0001] The energy efficiency of lighting has become an important
consideration in industrial, consumer, and architectural lighting
applications. With the advances in solid state light technology,
light emitting diodes (LEDs) have become more energy efficient than
fluorescent lights. Further, the marketplace has a large
established fixture base for Edison, fluorescent and high intensity
discharge lights. These types of applications present a significant
technical challenge for LEDs due to their inherent point source
nature, and the need to operate the LEDs at relatively low
temperatures. Today there are many solutions addressing these
issues, including fans, thermal sinks, heat pipes and the like.
However, these approaches limit the applications by adding
complexity, cost, efficiency loss, added failure modes, and an
undesirable form factor. The need remains to find a solution that
can provide optical and efficiency benefits, at attractive
manufacturing costs and design.
SUMMARY
[0002] A light, consistent with the present invention, includes a
light source, an optical guide, and a thermal guide. The optical
guide is coupled to the light source for receiving and distributing
light from the light source, and the thermal guide is integrated
with the optical guide for providing thermal conduction from the
light source for cooling the light.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The accompanying drawings are incorporated in and constitute
a part of this specification and, together with the description,
explain the advantages and principles of the invention. In the
drawings,
[0004] FIG. 1 is a diagram illustrating a solid state light source
with an optical guide and integrated thermal guide;
[0005] FIG. 2 is a perspective view of a solid state light using an
optical guide sheet and co-extensive thermal guide;
[0006] FIG. 3 is a side view of the light of FIG. 2;
[0007] FIG. 4 is a perspective view of a solid state light using an
optical guide sheet and dual co-extensive thermal guides;
[0008] FIG. 5 is a side view of the light of FIG. 4;
[0009] FIG. 6 is a cross sectional side view of a solid state light
using an optical guide having an exterior portion for emitting
light and an interior portion for cooling;
[0010] FIG. 7 is a top view of the light of FIG. 6;
[0011] FIG. 8 is a bottom view of the light of FIG. 6;
[0012] FIG. 9 is a cross sectional side view of a solid state light
with an active cooling element;
[0013] FIG. 10 is a side view of a solid state light with a thermal
guide having an air passage;
[0014] FIG. 11 is a top view of the light of FIG. 10;
[0015] FIG. 12 is a side view of a solid state light with a thermal
guide having an air passage;
[0016] FIG. 13 is a top view of the light of FIG. 12;
[0017] FIG. 14 is a side view of a solid state light with a thermal
guide having a single aperture;
[0018] FIG. 15 is a top view of the light of FIG. 14;
[0019] FIG. 16 is a diagram illustrating an optical guide with
light extraction features;
[0020] FIG. 17 is a diagram illustrating an optical guide with
apertures for cooling or as extraction features;
[0021] FIG. 18 is a diagram illustrating an optical guide with a
reflective layer;
[0022] FIG. 19 is a top view of a heat spreader prior to forming
features that couple to fins for the thermal guide;
[0023] FIG. 20 is a top view of the heat spreader of FIG. 19 after
forming the features;
[0024] FIG. 21 is a side view of the heat spreader of FIG. 19 after
forming the features; and
[0025] FIG. 22 is a top view of the heat spreader of FIG. 19 after
forming the features.
DETAILED DESCRIPTION
[0026] FIG. 1 is a diagram illustrating components of a light 10
having a power circuit 12, a solid state light source 14, and a
thermo optical guide comprising an optical guide 16 and an
integrated thermal guide 18. Power circuit 12 receives power from a
power supply and provides the required voltage and current to drive
solid state light source 14, which is optically coupled to optical
guide 16. In particular, solid state light source 14 injects light
into optical guide 16, which receives and distributes the light.
Optical guide 16 includes light injection, light transport, and
light extraction zones or elements in order to distribute the
light.
[0027] Thermal guide 18 is integrated with optical guide 16 in
order to draw heat from solid state light source 14 through
conduction and dissipate the heat through convection to cool light
10 and to efficiently utilize both area and volume for the cooling.
Thermal guide 18 includes heat acquisition, heat spreading, and
heat dissipation zones or elements in order to cool the light.
Through integration of the optical and thermal guides, embodiments
of this invention overcome many of the limitations of current solid
state light concepts such as those identified above.
[0028] Solid state light source 14 can be implemented with, for
example, LEDs, organic light emitting diodes (OLEDs), or other
solid state light sources. Certain embodiments can provide for
uniformly distributed light from the solid state light source.
Alternatively, lenses can be used to focus the emitted light. For
example, in certain embodiments the light can produce a cone or
curtain of light. The lenses could have air permeability for
cooling and can include Fresnel lenses, prismatic structures, or
lenslet structures. The solid state light sources can emit light of
various colors for decorative or other lighting effects. Solid
state light source 14 is electrically connected with power circuit
12, which can include a flexible circuit or other circuitry for
powering the solid state light source. The circuitry to power the
light source can include dimming circuitry and electronics to
control frequency shifting or color shifting components that help
produce a more desirable light, and an example of such electronics
are described in U.S. patent application Ser. No. 12/137667,
entitled "AC Illumination Apparatus with Amplitude Partitioning,"
and filed Jun. 12, 2008, which is incorporated herein by reference
as if fully set forth.
[0029] Optical guide 16 can be implemented with, for example, a
transparent or translucent material capable of receiving light from
the solid state light source and emitting the light. For example,
optical guide 16 preferably is made of an optically suitable
material such as polycarbonate, polyacrylates such as polymethyl
methacrylate, polystyrene, glass, or any number of different
plastic materials having relatively high refractive indexes. The
optical guide can be configured in a variety of shapes such as a
bulb, sphere, cylinder, cube, sheet, or other shape. Furthermore,
the optical guide can include a matrix material that can contain
light frequency shifting chromaphores to obtain a more desirable
color rendering index, and examples of matrix stabilized dyes are
described in U.S. Pat. No. 5,387,458, which is incorporated herein
by reference as if fully set forth.
[0030] Thermal guide 18 can be implemented with a material capable
of conducting heat from the solid state light source and
dissipating the heat. For example, the thermal guide is preferably
comprised of a material with a thermal conductivity from about 1
W/(m-K) to 1000 W/(m-K), and more preferably from 10 W/(m-K) to
1000 W/(m-K), and most preferable from 100 W/(m-K) to 1000 W/(m-K).
The thermal guide draws heat from the solid state light source
through conduction and dissipates heat into air through convection.
Optionally, components of the thermal guide can include heat pipes.
The thermal guide is integrated with the optical guide, meaning
that the thermal guide is in sufficient contact, directly or
indirectly, with the solid state light source in order to conduct
and dissipate heat from the solid state light source for the light
to function. For example, the thermal guide can draw heat from the
solid state light sources to maintain the light sources cool enough
to function as intended. The thermal guide can be directly in
physical contact with the solid state light sources or indirectly
in contact with them such as through a ring or other components
upon which the solid state light sources are mounted. The thermal
guide can also be in physical contact with the optical guide,
either directly or indirectly through other components.
Alternatively, the thermal guide need not be in physical contact
with the optical guide, provided that the thermal guide can conduct
sufficient heat from the solid state light sources in order for the
light to function. Therefore, the thermal guide resides either
co-extensively proximate at least a portion or preferably a
majority of the area of the optical guide, or the thermal guide
resides within at least a portion or preferably a majority of the
volume of the optical guide in the case of a bulb, sphere or other
three dimensional shape having an interior volume.
[0031] The thermal guide can include thermal conductive
enhancements such as metal coatings or layers, or conductive
particles, to help conduct the heat generated by the solid state
light sources into and along the thermal guide. Further, the
thermal guide can have convective thermal enhancements such as fins
and microstructures to increase the convective heat transfer
coefficient. The thermal guide can also have optical enhancements
in order to enhance the light output of the optical guide. For
example, the thermal guide can be formed from a reflective material
or a material modified to have a reflective surface such as white
paint, a polished surface, or a thin reflective material on its
surface.
[0032] FIGS. 2 and 3 are perspective and side views, respectively,
of a solid state light 20 using an optical guide sheet 24 and
co-extensive thermal guide 22. Light 20 includes a plurality of
solid state light sources 26 optically coupled with optical guide
sheet 24. For example, solid state light sources 26 can be located
within hemispherical or other types of depressions in the edge of
optical guide sheet 24 and possibly secured through use of an
optically clear adhesive. Optical guide sheet 24 distributes light
from the solid state light sources 26 through an emission surface
28, and it can be configured to provide substantially uniform
distribution of light across surface 28. Thermal guide 22 is
integrated with optical guide 24 by being sufficiently co-extensive
and in physical proximity with it in order to draw heat away from
solid state light sources 26 and dissipate the heat to maintain
light 28 cool enough to function.
[0033] FIGS. 4 and 5 are perspective and side views, respectively,
of a solid state light 30 using an optical guide sheet 34 and dual
co-extensive thermal guides 32 and 36. Light 30 includes a
plurality of solid state light sources 38 optically coupled with
optical guide sheet 34. For example, solid state light sources 38
can be located within hemispherical or other types of depressions
in the edge of optical guide sheet 34 and possibly secured through
use of an optically clear adhesive. Optical guide sheet 34
distributes light from the solid state light sources through an
emission end 40, and it can be configured to provide substantially
uniform distribution of light from end 40. Thermal guides 32 and 36
are integrated with optical guide 34 by being sufficiently
co-extensive and in physical proximity with it in order to draw
heat away from solid state light sources 38 and dissipate the heat
to maintain light 30 cool enough to function.
[0034] For lights 20 and 30, the optical guide and co-extensive
thermal guide can be configured in a variety of shapes, aside from
planar. For example, they can be formed in a circle, spiral, or a
non-planar shape for decorative or other lighting effects. The
optical guide can be formed from, for example, polycarbonate,
polyacrylates such as polymethyl methacrylate, polystyrene, glass,
or any number of different plastic materials having relatively high
refractive indexes. The co-extensive thermal guides can be formed,
for example, as a metallic coating on the optical guide.
[0035] FIG. 6 is a cross sectional side view of a preferred
embodiment of a solid state light 42 using an optical guide having
an exterior portion for emitting light and an interior portion for
cooling. FIGS. 7 and 8 are top and bottom views, respectively of
light 42. Light 42 includes an optical guide 52, integrated thermal
guide 54, and solid state light sources on an optional heat
spreader ring 46. The heat spreader ring 46 can operate by thermal
conduction or have a heat pipe or thermal siphon associated with
it. The heat spreader ring contains elements that efficiently
connect to the thermal guide, an example of which includes a ring
containing bent fin elements that are thermally connected to the
thermal guide. Alternatively, the solid state light sources can be
coupled directly to a thermal guide without a heat spreader ring.
For the solid state light sources, light 42 can include, for
example, LEDs 48, 50, 66, 68, 70, and 72 arranged around ring 46,
as shown in FIG. 8. The solid state light sources are optically
coupled to optical guide 52; for example, the light sources can be
located within hemispherical or other types of depressions in an
edge of optical guide 52 and possibly secured through use of an
optically clear adhesive.
[0036] A base 44 is configured to connect to a power supply, and it
can include a power circuit for providing the required voltage and
current from the power supply to drive the solid state light
sources. Base 44 can be implemented with, for example, an Edison
base for use with conventional light bulb sockets or a base for use
with conventional fluorescent light fixture connections. Air
passages 56 and 58 are provided between optical guide 52 and base
44 to provide free convection across thermal guide 54 through an
air passage 60.
[0037] In this exemplary embodiment, the thermal guide is
implemented with metallic fins 54, 62, and 64, as illustrated in
FIG. 7. The fins are integrated with light guide 52, as shown in
FIGS. 7 and 8, in order to draw heat from solid state light sources
48, 50, 66, 68, 70, 72 and dissipate the heat through convection by
air flow in air passage 60. The thermal guide can optionally
include a heat pipe or thermal siphon. Optical guide 52 can be
implemented with, for example, polycarbonate, polyacrylates such as
polymethyl methacrylate, polystyrene, glass, or any number of
different plastic materials having relatively high refractive
indexes.
[0038] The exterior portion of light 42 can be used to distribute
and emit light from the solid state light sources, and the interior
portion of light 42 is used for cooling the thermal guide and solid
state light sources. Optical guide 52 can be formed in a bulb
shape, as represented in FIG. 6, or in other shapes. With certain
shapes, such as a bulb shape shown in FIG. 6, the interior portion
of optical guide 52 can form an interior volume, and the thermal
guide can be integrated with the interior volume of the optical
guide for providing thermal conduction from the solid state light
sources.
[0039] FIG. 9 is a cross sectional side view of a solid state light
74 with an active cooling element 88. Light 74 can have a similar
construction as light 42. Light 74 includes a base 76, an optical
guide 84, a thermal guide 86, and solid state light sources, such
as LEDs 80 and 82, arranged on an optional heat spreader ring 78.
Active cooling element 88, such as a fan, draws air through air
passage 87 for cooling in addition to free convection. Active
cooling element 88 can be coupled to a power source through base
76, and it can run continuously when light 74 is in operation or
can include a temperature sensor to active it only when light 74 is
above a certain temperature.
[0040] FIGS. 10-15 illustrate additional configurations of solid
state lights having an optical guide with an exterior portion for
emitting light and an interior portion for cooling via an
integrated thermal guide. They can function in a manner similar to
light 42 as described above. FIGS. 10 and 11 are side and top
views, respectively, of a solid state light 90 with a perforated
air passage opening. Light 90 includes a base 92 for connection to
a power supply, an optical guide 98 for distributing light, an air
passage 100 through optical guide 98, and a thermal guide
associated with optical guide 98. The thermal guide includes fins
102, a ring 94, and a perforated portion 96 between base 92 and
ring 94. Perforated portion 96 allows for air flow through air
passage 100. Fins 102 of the thermal guide conduct heat from ring
94 and dissipate the heat through convection in air passage
100.
[0041] FIGS. 12 and 13 are side and top views, respectively, of a
solid state light 104 with a thermal guide having plurality of
apertures. Light 104 includes a base 106 for connection to a power
supply, an optical guide 114 for distributing light, an air passage
116 through optical guide 114, and a thermal guide associated with
optical guide 114. The thermal guide includes fins 118, a ring 108,
and a section 110 having a plurality of apertures 112 between base
106 and ring 108. Apertures 112 allow for air flow through air
passage 116. Fins 118 of the thermal guide conduct heat from ring
108 and dissipate the heat through convection in air passage
116.
[0042] FIGS. 14 and 15 are side and top views, respectively, of a
solid state light 120 with a thermal guide having a single
aperture. Light 120 includes a base 122 for connection to a power
supply, an optical guide 130 for distributing light, an air passage
132 through optical guide 130, and a thermal guide associated with
optical guide 130. The thermal guide includes fins 134, a ring 124,
and a section 126 having an aperture 128 between base 122 and ring
124. Aperture 128 allows for air flow through air passage 132. Fins
134 of the thermal guide conduct heat from ring 124 and dissipate
the heat through convection in air passage 132.
[0043] FIGS. 16-18 illustrate various optional features for an
optical guide for the solid state lights described above. FIG. 16
is a diagram illustrating an optical guide 140 with light
extraction features 142. Such light extraction features can be used
to provide for greater or more uniform distribution of light
emitted by the optical guide, or the extraction features can
provide for particular optical effects such as tailoring the light
pattern for particular illumination patterns. Examples of
extraction features include a pattern of dots or other shapes of
light extraction material printed or otherwise affixed onto the
exterior or interior surface of the optical guide. Extraction
features can also include roughening of the exterior of the optical
guide through sandblasting or other techniques, and other
extraction features include microstructured features formed on a
surface such as microstructured prisms or lenslets.
[0044] FIG. 17 is a diagram illustrating an optical guide 144 with
apertures 146 for cooling. If the solid state light is mounted
substantially horizontally, apertures 146 can provide for air flow
through the optical guide and across the thermal guide for the
cooling though convection rather than air flow substantially along
the interior surface of the optical guide such as through air
passage 60. Apertures 146 can also function as extraction
features.
[0045] FIG. 18 is a diagram illustrating an optical guide 148 with
a reflective layer 150. Optical guide 148 can include reflective
layer 150 on its interior surface such that a portion of light
distributed through optical guide 148 is reflected by reflective
layer 150 and emitted from exterior surface 152 rather than being
emitted from the interior surface of the optical guide. An example
of a reflective layer is the Enhanced Specular Reflective (ESR)
film product available from 3M Company.
[0046] FIGS. 19-22 illustrate a heat spreader 160 with features for
use in mounting fins of a thermal guide. FIG. 19 is a top view of
heat spreader 160 prior to forming the features that couple to fins
for the thermal guide. FIGS. 20, 21, and 22 are top, side, and
perspective view, respectively, of heat spreader 160 after forming
the features. Heat spreader 160 can operate in a manner similar to
heat spreader ring 46 as described above but with the additional
features for mounting cooling fins for connection with the thermal
guide.
[0047] As shown in FIG. 19, heat spreader 160 has a ring portion
162 and triangularly shaped sections 164, 166, 168, and 170. In a
manufacturing process, heat spreader 160 can be formed from a sheet
of metal or other material. For example, a stamping process can be
used to cut heat spreader 160 from the sheet of metal and bend
sections 164, 166, 168, and 170 to substantially right angles to
ring portion 162, as shown in FIGS. 20-22, forming upward
protrusions.
[0048] The solid state light sources can be mounted on ring portion
162 in a manner similar to the LEDs mounted on heat spreader ring
46. Cooling fins of a thermal guide, such as the fins described
above, can be thermally connected to sections 164, 166, 168, and
170 such as through soldering, conductive epoxy, clips, or in other
ways. In that manner, heat spreader 160 with the mounting features
effectively becomes part of the thermal guide and can be easily
manufactured from a sheet of material. Four triangularly shaped
sections 164, 166, 168, and 170 are shown for illustrative purposes
only. More or fewer features can be used, and the features can have
various shapes, depending upon, for example, a configuration of the
cooling fins to which they are to be connected.
* * * * *