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Publication numberUS20080186695 A1
Publication typeApplication
Application numberUS 11/693,597
Publication dateAug 7, 2008
Filing dateMar 29, 2007
Priority dateFeb 3, 2007
Publication number11693597, 693597, US 2008/0186695 A1, US 2008/186695 A1, US 20080186695 A1, US 20080186695A1, US 2008186695 A1, US 2008186695A1, US-A1-20080186695, US-A1-2008186695, US2008/0186695A1, US2008/186695A1, US20080186695 A1, US20080186695A1, US2008186695 A1, US2008186695A1
InventorsGeorge K. Awai, Michael D. Ernst, Alain S. Corcos
Original AssigneeAwai George K, Ernst Michael D, Corcos Alain S
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Light emitting diode assemblies for illuminating refrigerated areas
US 20080186695 A1
Abstract
An LED assembly for illuminating a refrigerated area includes a plurality of LED modules and a reflector base configured to reflect light generated by the plurality of LED modules into the refrigerated area. The reflector base is further configured to conduct heat away from the plurality of LED modules and also includes a base cooling channel. Both the reflector base and the plurality of LED modules are located substantially within the refrigerated area. The LED assembly also includes an external heat sink coupled to the reflector base, and configured to conduct heat away from the reflector base, wherein the external heat sink is further configured to be mounted substantially outside the refrigerated area. The LED assembly can include a doom lens that forms a doom cooling channel substantially enclosing the reflector base. This internal heat sink includes an internal sink cooling channel.
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Claims(14)
1. A light emitting diode (LED) assembly useful for illuminating a refrigerated area, the LED assembly comprising:
a plurality of LED modules;
a reflector base configured to reflect light generated by the plurality of LED modules into the refrigerated area and is further configured to conduct heat away from the plurality of LED modules, wherein the reflector base includes a base cooling channel, and wherein the reflector base and the plurality of LED modules are configured to operate substantially within the refrigerated area; and
an external heat sink coupled to the reflector base, and configured to conduct heat away from the reflector base, wherein the external heat sink is further configured to be mounted substantially outside the refrigerated area.
2. The LED assembly of claim 1 further comprising a doom lens forming a doom cooling channel substantially enclosing the reflector base.
3. The LED assembly of claim 1 further comprising an internal heat sink configured to be mounted substantially within the refrigerated area and further configured to conduct heat from the reflector base to the external heat sink and wherein the internal heat sink includes an internal sink cooling channel.
4. The LED assembly of claim 1 wherein the external heat sink includes an external sink cooling channel.
5. A light emitting diode (LED) assembly useful for illuminating a refrigerated area, the LED assembly comprising:
a plurality of LED modules;
a conductive base configured to conduct heat away from the plurality of LED modules coupled to the conductive base, wherein the conductive base includes a base cooling channel, and wherein the conductive base and the plurality of LED modules are configured to operate substantially within the refrigerated area;
an external heat sink coupled to the conductive base, and configured to conduct heat away from the conductive base, wherein the external heat sink is further configured to be mounted substantially outside the refrigerated area; and
wherein at least one of the plurality of LED modules includes:
an LED base;
an LED located substantially within the LED base and configured to generate a light beam;
an inner beam director; and
an outer beam director, wherein an interface between the inner beam director and the outer beam director is shaped to refract and reflect the light beam along the interface, thereby narrowing a substantial portion of the light beam.
6. The LED assembly of claim 5 wherein the LED has a geometrically coated phosphor layer.
7. The LED assembly of claim 5 wherein the interface between the inner beam director and the outer beam director includes an intermediate beam director configured to further refract and reflect the light beam generated by the LED.
8. The LED assembly of claim 5 wherein the shaped interface is curved.
9. The LED assembly of claim 5 wherein the shaped interface is highly reflective.
10. The LED assembly of claim 7 wherein the intermediate beam director is highly reflective.
11. The LED assembly of claim 5 wherein the inner beam director has a first N value and the outer beam director has a second N value, and wherein the first N value is substantially lower than the second N value.
12. The LED assembly of claim 5 further comprising a doom lens forming a doom cooling channel substantially enclosing the conductive base.
13. The LED assembly of claim 5 further comprising an internal heat sink configured to be mounted substantially within the refrigerated area and further configured to conduct heat from the conductive base to the external heat sink and wherein the internal heat sink includes an internal sink cooling channel.
14. The LED assembly of claim 5 wherein the external heat sink includes an external sink cooling channel.
Description
CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of U.S. application Ser. No. 11/670,981, filed on Feb. 3, 2007, pending, and entitled “Light Emitting Diode Modules for Illuminated Panels”, incorporated by reference in its entirety; and co-pending and concurrently filed application Ser. No. ______, (Attorney Docket No. IM 0702) filed Mar. 29, 2007, entitled “Light Emitting Diode Waveguide Assemblies for Illuminating Refrigerated Areas”, by George K. Awai, Michael D. Ernst and Alain S. Corcos, which is incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

This invention relates generally to illuminating panels. More particularly, this invention relates to light emitting diode (LED) modules for illuminating refrigerated areas.

Refrigerated display areas, such as supermarket freezers, make use of interior case lighting to illuminate products and to attract shoppers. In addition, the lighting should generate minimal heat so as to reduce cooling requirements and avoid spoilage of the displayed food.

Fluorescent lighting are commonly used and are mounted vertically along the inside edge of the glass display doors of refrigerated areas. Although fluorescent lighting generate less heat and are more efficient than incandescent lighting, fluorescent lighting suffer from decreased light output and reduced lamp life when operated in cold temperature environments. Florescent lighting also produces diffused light patterns and hence do not illuminate the food products efficiently.

Recent attempts at replacing florescent lighting with LEDs resulted in very limited success for several reasons. While the compact size and durability of LEDs makes them suitable for compact edge lighting for illuminated display doors, LEDs, especially high-powered LEDs, generate a substantial amount of heat which substantially increase cooling load of the refrigerated areas.

It is therefore apparent that an urgent need exists for LED assembly/structures that are suitable for evenly and efficiently illuminating refrigerated displays, and is easy to manufacturer, easy to maintain, shock resistant, impact resistant, portable, cost effective, and have long lamp-life.

SUMMARY OF THE INVENTION

To achieve the foregoing and in accordance with the present invention, light emitting diode (LED) assemblies for illuminating refrigerated display areas are provided. Such LED assemblies can be operated very efficiently, cost-effectively and with minimal maintenance once installed in the field.

In accordance with one embodiment of the invention, an LED assembly provides illumination for a refrigerated area, the LED assembly including a plurality of LED modules and a reflector base configured to reflect light generated by the plurality of LED modules into the refrigerated area. The reflector base is further configured to conduct heat away from the plurality of LED modules and also includes a base cooling channel. Both the reflector base and the plurality of LED modules are located substantially within the refrigerated area.

The LED assembly also includes an external heat sink coupled to the reflector base, and configured to conduct heat away from the reflector base, wherein the external heat sink is further configured to be mounted substantially outside the refrigerated area. The external heat sink can include an integral cooling channel.

The LED assembly can include a doom lens that forms a doom cooling channel substantially enclosing the reflector base. An internal heat sink can also be mounted substantially within the refrigerated area thereby conducting heat from the reflector base to the external heat sink. This internal heat sink includes an internal sink cooling channel.

In some embodiments, at least one of the plurality of LED modules includes an LED base, an LED located substantially within the LED base and configured to generate a light beam, an inner beam director, and an outer beam director. The interface between the inner beam director and the outer beam director is shaped to refract and/or reflect the light beam along the interface, thereby narrowing a substantial portion of the light beam into the refrigerated area.

These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention may be more clearly ascertained, one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a front view showing three illuminated doors for a refrigerated space in accordance with the invention;

FIGS. 2A, 2B are a cross-sectional side view of one of the illuminated wall pillars for the refrigerated area of FIG. 1 and also shows display shelves;

FIGS. 3A-3D are cross-sectional views of several embodiments of LED assemblies for the illuminated pillar of FIG. 2A;

FIG. 4 illustrates a variant of the embodiment shown in FIG. 3B;

FIGS. 5A-5C are cross-sectional views of additional embodiments of LED assemblies for the illuminated pillar of FIG. 2A;

FIG. 6 illustrates a variant of the embodiment shown in FIG. 5B;

FIGS. 7A, 7B and 7C are an isometric view, a cut-away view and a cross-sectional view, respectively, of an LED module 700 in accordance with an aspect of the present invention;

FIGS. 7D, 7E are cross-sectional views of a substantially reflective module and a refractive/reflective module in accordance with the present invention;

FIGS. 8A-10E are cross-sectional views of additional embodiments of the LED modules of the present invention; and

FIG. 11 is a cross-sectional view of another embodiment of LED assembly for the illuminated pillar of FIG. 2A.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of the present invention may be better understood with reference to the drawings and discussions that follow.

In accordance with the present invention, FIG. 1 is a front view showing an illuminated refrigerated display area 100 with a plurality of doors including doors 110, 120, 130. Door 110 includes a transparent panel 112, a frame 114 and a door handle 116. For clarity, doors 120, 130 are shown partially cut-away to expose a support pillar 105 and a horizontal span 108.

FIG. 2A is a cross sectional side view showing pillar 105 of FIG. 1 and also shows display shelves 210 a, 210 b . . . 210 k supported by corresponding brackets 215 a, 215 b . . . 215 k. An LED assembly 240 (described in greater detail below) is attached to the refrigerated side of vertical pillar 105. LED assembly 240 can also be coupled to an external heat sink 245 via heat pipes 248 a, 248 b, 248 c, 248 d . . . and 248 m, thereby enabling LED assembly 240 to dissipate heat outside the refrigerated area.

FIGS. 3A-3D are cross sectional views of exemplary embodiments 300A, 300B, 300C, 300D for the LED assembly 240 of the present invention, and correspond to cross section line 1A-1A of FIG. 1. Referring first to FIG. 3A, LED assembly 300A includes doom lens 310, reflector base 320 a, LED boards 362, 364, internal heat sink 350 a, conductors 342, 344, 346 and external heat sink 340 a.

Doom lens 310 is located substantially within the refrigerated side of wall 330, while external heat sink 340 a is located on the ambient side of wall 330. Lens 310 can be made from a suitable transparent or translucent material such as glass or a suitable polymer, e.g., acrylic or polycarbonate. Depending on the specific implementation, lens 310 can be clear or frosty. In addition, lens 310 can have optical characteristics such as that of a Fresnel lens which can be incorporated onto the protected inner surface of lens 310.

Each LED boards 362, 364 includes a row of LED modules and the circuitry for coupling the LED modules to a suitable power source (not shown). Suitable LED modules are commercially available from OSRAM Opto Semiconductors Inc. of Santa Clara, Calif., Nichia Corporation of Detroit, Mich., Cree Inc. of Durham, N.C., or Philips Lumileds Lighting Company of San Jose, Calif. LED boards 362, 364 may also include some of the power circuitry components such as resistors and may also include sensors such as temperature sensors and/or illumination level sensors.

LED boards 362, 364 are mounted on reflector base 320 a which focuses light rays 371 a, 372 a and rays 381 a, 382 a into rays 371 b, 372 b and rays 381 b, 382 b, respectively, onto the display area located in the refrigerated side of wall 330.

Reflector base 320 a which is coupled to internal heat sink 350 a. Conductors 342, 344, 346 couple internal heat sink 350 a to external heat sink 340 a through wall 330. As a result, the heat generated by LED boards 362, 364 can be conducted from reflector base 320 a to internal heat sink 350 a, and in turn to external heat sink 340 a via conductors 342, 344, 346.

In accordance with the present invention, the heat dissipation capability of reflector base 320 a and heat sinks 350 a, 340 a is further enhanced by lens cooling channel 315, base cooling channel 325 a and heat sink cooling channel 355 a. As illustrated by both FIGS. 1 and 2A, in this embodiment cooling channels 315, 325 a, 355 a are oriented vertically and hence are capable of efficiently dissipating heat via air convection from ambient air drawn from outside the refrigerated space, thereby substantially reducing the amount of heat dissipated into the refrigerated space. Circulation of cooling air can also be from forced air cooling. It is also possible to divert some of the chilled air from the refrigerated space into one or more of cooling channels 315, 325 a, 355 a. While air is used as the exemplary cooling medium in this embodiment, it is also possible to use other suitable fluids and gases known to one skilled in the refrigeration arts such as Freon, R12 and R134a.

FIG. 3B shows a variant 300B of the LED assembly 240, in which the cooling surface area of heat sink cooling channel 355 b is substantially increased by introducing ribs or groves into the internal surface of channel 355 b thereby enhancing the heat dissipating capability of LED assembly 300B and substantially reducing the heat dissipated into the refrigerated space. In this embodiment, ribs or groves can also be incorporated onto the surface of external heat sink 340 b to further increase the heat dissipation capability of external heat sink 340 b into the ambient air.

Other modifications are also possible. For example, as shown in FIG. 3C, light rays 371 a, 372 a, 381 a, 382 a produced by yet another embodiment 300C of LED assembly 240 are focused into rays 371 b, 372 b, 381 b, 382 b, respectively, by a pair of curved reflectors located on reflector base 320 c. The shape and orientation of these reflectors of base 320 c can vary in accordance to the width and depth of display shelves 210 a, 210 b . . . 210 k. As shown in FIG. 3D, in some implementations, LED assembly 300D can have three LED boards 362, 364, 368.

Referring again to FIG. 1, it is also possible to mount any one of LED assemblies 300A, 300B, 300C and 300D vertically along the refrigerated side of door frame 114 and corresponding to cross section line 1B-1B.

FIG. 4 is a cross sectional view of yet another embodiment 400 for the LED assembly 240 of the present invention, and corresponds to section line 1C-1C of door frame 114. External heat sink 440 is coupled to internal heat sink 350 b via heat conducting connectors 442, 444. In this embodiment, external heat sink 440 also includes a ribbed cooling channel 448. As a result, external heat sink 440 is shaped to also function as a door handle which is now warmer and more comfortable for a customer to use because external heat sink 440 is now dissipating heat generated by LED assembly 400.

Referring back to FIG. 1, instead of vertical mounting, LED assemblies 300A, 300B and 300C can also be modified to operate in a horizontal orientation along a top front span 108 of refrigerated area 100 corresponding to section line 1E-1E, by for example eliminating one of the LED board and also using forced air cooling. This horizontal variant of LED assemblies 300A, 300B and 300C can also be mounted along the top of door frame 114 corresponding to section line 1D-1D.

Alternatively, as shown in FIG. 2B, it is also possible to horizontally mount LED assemblies 242 a, 242 b . . . 242 k, with each LED assembly spanning vertical pillars, e.g., spanning pillar 105 and the adjacent pillar located between doors 110, 120, of refrigerated area 100.

FIGS. 5A, 5B, 5C are additional cross sectional views of additional variants 500A, 500B, 500C for exemplary vertical LED assembly 240 and horizontal LED assemblies 242 a, 242 b . . . 242 k in accordance with the present invention.

Referring first to FIG. 5A, LED assembly 500A includes an optical waveguide 510 a, LED board 560, conductive base 545, thermal barrier 535, external heat sink 540 a and external cooling doom 520. Waveguide 510 a is located substantially within the refrigerated side of wall 530, while the rest of assembly 500A, including cooling doom 520, is located substantially on the ambient air side of wall 530.

LED board 560 includes a row of LED modules and the circuitry for coupling the LED modules to a suitable power source (not shown). Suitable LED modules are commercially available from OSRAM Opto Semiconductors Inc. of Santa Clara, Calif., Nichia Corporation of Detroit, Mich., Cree Inc. of Durham, N.C., or Philips Lumileds Lighting Company of San Jose, Calif. LED board 560 may also include some of the power circuitry components such as resistors and may also include sensors such as temperature sensors and/or illumination level sensors.

By repeatedly reflecting and refracting light rays generated by LED board 560, waveguide 510 a provides a pair of evenly-illuminated and focused light beams into the refrigerated area. For example, light ray 571 a is internally reflected as light ray 571 b, which is refracted outside waveguide as light ray 571 c and also internally reflected as light ray 571 d, and further refracted and reflected into light rays 571 e, 571 f, respectively. Light ray 571 f is then refracted as light ray 571 g and reflected as light ray 571 h, which in turn is refracted and reflected into light rays 571 k, 571 m, respectively.

Similarly, light ray 572 a is internally reflected as light ray 572 b, which is refracted outside waveguide as light ray 572 c and also internally reflected as light ray 572 d, and further refracted and reflected into light rays 572 e, 572 f, respectively. Light ray 572 f is then refracted as light ray 572 g and reflected as light ray 572 h, which in turn is refracted and reflected into light rays 572 k, 572 m, respectively.

LED board 560 is mounted on conductive base 545 which in turn is coupled to external heat sink 450 a. As a result, the heat generated by LED board 560 can be conducted by base 545 to external heat sink 540 a, and then dissipated outside the refrigerated area.

In accordance with the present invention, the heat dissipation capability of heat sink 540 a is further enhanced by cooling channel 525 formed by external cooling doom 520. As illustrated by both FIGS. 1 and 2, in this embodiment cooling channel 525 is oriented vertically and hence is capable of efficiently dissipating heat via air convection from ambient air drawn from outside the refrigerated space, thereby substantially reducing the amount of heat dissipated into the refrigerated space. Circulation of cooling air can also be from forced air cooling. It is also possible to divert some of the chilled air from the refrigerated space into cooling channel 525.

FIG. 5B shows a variant 500B of the LED assembly 240, in which the cooling surface area of heat sink 540 b is substantially increased by incorporating ribs or groves onto the surface of external heat sink 540 b thereby enhancing the heat dissipating capability of LED assembly 300B and further reducing the heat dissipated into the refrigerated space by LED board 530 and waveguide 510 a.

Other waveguide profiles are also possible and include straight, tapered, and curved shapes and combinations thereof. For example, as shown in FIG. 5C, waveguide 510 c has a straight body and a curved tip.

FIG. 6 is a cross sectional view of yet another embodiment 600 for the LED assembly 240 of the present invention, and corresponds to cross section line 1C-1C of door frame 114. In this embodiment, external heat sink 640 also includes a cooling channel 648 and is shaped as a door handle which is now warmer and more comfortable for the customer's use because external heat sink 640 is now dissipating heat from LED board 560 via base 645.

In some embodiments, since white LEDs are not the most efficient emitter of light, it is also possible for LED board 560 to transmit light in the substantially blue-to-ultraviolet range into optical waveguides 510 a, 510 c that have been impregnated with phosphors, enabling waveguides 510 a, 510 c to convert the blue-to-ultraviolet light into white light or any colored light within the visible spectrum.

FIGS. 7A, 7B and 7C are an isometric view, a cut-away view and a cross-sectional view, respectively, of a highly efficient LED module 700 in accordance with another aspect of the present invention. LED module 700 includes a base 710, an outer beam director 720, an inner beam director 730, and an LED 790.

Suitable materials for base 710 include high temperature acrylic co-polymer and for beam directors 720, 730 include acrylic and optical grade silicone. Depending on the application, beam directors 720, 730 can be an optically clear material or slightly diffusive. LEDs suited for LED 790 include commercially available LEDs from OSRAM Opto Semiconductors Inc. of Santa Clara, Calif. such as model numbers LW-E6SG, LW-G6SP and LW-541C.

Since most efficient LEDs typically generate substantially more blue and ultraviolet light, LED 790 can be geometrically coated with a suitable phosphor layer, also known as conformal phosphor coating (not shown), known to one skilled in the art so as to produce a compact LED capable of generating a whiter light beam whose spectrum is better suited for illuminating display panels. This is possible because an even phosphor coating minimizes chromatic separation of the white light generated by LED 790. It is also possible to use LEDs that generate a whiter light spectrum without an additional phosphor layer.

While LEDs have been used for illumination applications, most commercially available LED packages are designed to generate a fairly wide-angled and evenly-spread beam of light for applications such as area lighting. Hence, these off the shelf LED packages are not suitable for edge illumination of display panels because a wide-angled beam will generate a substantially higher level of illumination closer to the edge of the display panels resulting in uneven illumination.

In contrast, light sources for edge illumination of the display panels should be capable of generating a substantially narrow beam of penetrating light so as to evenly illuminate the central portions of the display panels which can have a large display surface area.

In accordance with one aspect of the present invention as illustrated by FIG. 7C, the deep penetration needs are accomplished primarily by reliance on the refractive and/or reflective properties of the interface between outer beam director 720 and inner beam director 730. The refractive and/or reflective properties can be controlled by selecting suitable interface profiles and N index values. Suitable profiles for beam director interfaces include parabolic and elliptical curved shapes. Suitable N values include for example, N1 being approximately 1.33 to 1.41 and N2 being approximately 1.49 to 1.6 for beam directors 720 and 730, respectively. In some embodiments, most of the light produced by LED module 700 is substantially concentrated within an approximately 40 degree beam angle.

Accordingly, exemplary light rays 760 a, 770 a produced by LED 790 are refracted by beam directors 720, 730 into rays 760 b, 770 b, respectively. Light rays 760 b, 770 b are further refracted by the external surface of outer beam director 720 into rays 760 c, 770 c, and thereby enabling LED module 700 to generate a substantially narrower beam of light than that initially produced by LED 790.

FIG. 7D shows a modified LED module 700D in which a reflective layer 740 is added between outer beam director 720 and inner beam director 730 thereby enhancing the reflective properties of the interface between beam directors 720, 730. Reflective layer 740 can be formed by techniques well known in the art including vapor and electrostatic deposition. Light rays 760 a, 770 a produced by LED 790 are reflected by layer 740 into rays 760 b, 770 b, respectively, enabling LED module 700D to produce a substantially narrow and penetrating beam of light including rays 760 c, 770 c.

As discussed above, a substantially wide-angled beam will better illuminate the surface of display panels closest to the light source, while a substantially narrow light beam is especially beneficial for deeper penetration of relatively large display panels. At first blush, the shallow penetration and deep penetration needs appear to be competing requirements.

In accordance with another aspect of the present invention as illustrated by the cross-sectional view of FIG. 7E, both shallow and deep penetration needs can be accomplished by reliance on a suitable balance between the reflective and/or refractive properties of the interface between outer beam director 720 and inner beam director 730. This delicate refractive/reflective balance can be controlled by selecting suitable materials with suitable relative N values for directors 720, 730, e.g. N1 being approximately 1.33 to 1.41 and N2 being approximately 1.49 to 1.6, respectively.

For example, light ray 760 is refracted into ray 764 b and also reflected as ray 762 b, while light ray 770 is reflected into ray 774 b and also reflected as ray 772 b. Hence, LED module 700 is now capable of producing a substantially narrow beam of light, e.g., rays 762 c, 772 c, for penetrating the display panel while still able to produce enough shorter range light rays, e.g., rays 764 c, 774 c to illuminate the closer surface of the display panel. As a result, LED module 700 is capable of generating variable intensity ranges at various beam angles, e.g., 80% intensity at between 0 and 40 degrees, and 20% intensity between 40 to 80 degrees.

Several additions and modifications to LED module 700 are also possible as shown in the exemplary cross-sectional views of FIGS. 8A through 10E. Many other additions and modifications are also possible within the scope of the present invention.

FIGS. 8A and 8B show embodiments 800A, 800B with substantially straight interface profiles between outer beam directors 820 a, 820 b and inner beam directors 830 a, 830 b, respectively. Note the cone-shaped inner beam director 830 a and cylindrical-shaped inner beam director 830 b.

FIGS. 9A-9C illustrate additional embodiments with multiple refractive and/or reflective interfaces introduced by adding intermediate beam directors, i.e., directors 932 of module 900A, directors 934, 938 of module 900B, and director 932 of module 900C. As discussed above, the multiple interfaces can have refractive and/or reflective properties defined by suitable interface profiles and N values.

For example, light rays 960 a, 970 a produced by LED 790 are refracted by the interface between beam directors 930, 932 into rays 960 b, 970 b, respectively. Light rays 960 b, 970 b are further refracted by the external surface of intermediate beam director 932 into rays 960 c, 970 c.

Similarly, light rays 965 a, 975 a produced by LED 790 are refracted by the interface between beam directors 932, 930 into rays 965 b, 975 b, respectively, which are in turn further refracted by the interface between beam directors 920, 932 into rays 965 c, 975 c. Light rays 965 c, 975 c are then refracted by the external surface of outer beam director 920 into rays 765 d, 775 d.

As a result, a focused beam of light including exemplary light rays 965 d, 960 c, 970 c, 975 d is formed, enabling LED module 900A to generate a substantially narrower and penetrating beam of light than that initially produced by LED 790. As discussed above, the balance between the refractive and/or reflective properties of beam directors 920, 932, 930 can be controlled by selecting suitable materials with suitable relative N values for directors 920, 932, 930. In addition, beam directors 920, 932, 930 can be optically clear or slightly diffusive.

The cross-sectional views of FIGS. 10A-10E show additional possible LED module embodiments, e.g., module 1000A without an inner beam director; module 1000B with a concave-topped inner beam director 1032; module 1000C with a convex-topped inner beam director 1034; module 1000D has an exposed LED 790 and a substantially reflective layer 1042 with a curved profile; and module 1000E has an exposed LED 790 and a substantially reflective layer 1044 with a cone-shaped profile.

FIG. 11 shows how the focused-beam LED modules described above, e.g., LED modules 700, 800A, 800B . . . 1000E can be incorporated into the LED assemblies 240 and 242 a of the present invention. In this example, LED boards 1162, 1164 each include at least one focused-beam LED module, and hence LED boards 1162, 1164 can be mounted onto base 1120 of LED assembly 1100 without the need for external reflectors. Depending on the application, it may also be possible to combine focused-beam LED modules having different beam angles onto LED boards 1162, 1164.

Many modifications and variations are possible. For example, LED assemblies 300A, 300B, 300C, 400, 500A, 500B, 600, 1100 can be dimmable by adding a variable current control circuitry. An infrared red sensor can also be added to the control circuitry of assemblies 300A, 300B, 300C, 400, 500A, 500B, 600, 1100 so that the refrigerated area is illuminated when a potential customer enters the detection field thereby dimming or turning on and off in an appropriate manner.

Other modifications and variations are also possible. For example, it is also possible to sense the ambient light level of the surrounding and adjust the light output of the panels accordingly, thereby conserving power. The present invention can also improve the quality and quantity of light transmitted by other non-point light sources such as neon and fluorescent light sources.

In the above described embodiments, frame members of doors 110, 120 and the heat conducting components of LED assemblies 300A, 300B, 300C, 400, 500A, 500B, 600 can be manufactured from aluminum extrusions. The use of any other suitable rigid and heat-conducting framing materials including other metals, alloys, plastics and composites such as steel, bronze, wood, polycarbonate, carbon-fiber, and fiberglass is also possible.

In sum, the present invention provides improved LED assemblies for evenly illuminating refrigerated areas that is easy to manufacturer, easy to maintain, shock resistant, impact resistant, cost effective, and have long lamp-life.

While the present invention has been described with reference to particular embodiments, it will be understood that the embodiments are illustrative and that the inventive scope is not so limited. In addition, the various features of the present invention can be practiced alone or in combination. Alternative embodiments of the present invention will also become apparent to those having ordinary skill in the art to which the present invention pertains. Such alternate embodiments are considered to be encompassed within the spirit and scope of the present invention. Accordingly, the scope of the present invention is described by the appended claims and is supported by the foregoing description.

Referenced by
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US8434889 *Mar 19, 2010May 7, 2013GE Lighting Solutions, LLCLighted display case having reduced glare
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Classifications
U.S. Classification362/92
International ClassificationF25D27/00
Cooperative ClassificationF25D27/005, G02B6/001, F25D2700/04, G02B6/0085
European ClassificationF25D27/00B, G02B6/00L4L