HK1165851A - Light emitting diode luminaire - Google Patents

Description

Light emitting diode lighting device

Technical Field

The present invention relates to light emitting devices, and more particularly, to light emitting diode lighting devices.

Background

Light Emitting Diodes (LEDs) are attractive candidates for replacing conventional light sources, such as incandescent and fluorescent lamps. LEDs generally have higher light conversion efficiency than incandescent lamps and have longer lifetimes than both conventional light sources. Furthermore, some types of LEDs now have higher conversion efficiencies than fluorescent light sources, and higher conversion efficiencies have been shown experimentally.

Despite the advantages of using LEDs as light sources, consumer acceptance will be dictated at least in part by the variability in currently changing conventional light sources (i.e., incandescent or fluorescent) to light fixtures. LED light sources designed to directly replace conventional light sources can be helpful in promoting consumer acceptance, thereby revolutionizing the lighting industry. Unfortunately, significant challenges exist in designing LED light sources that directly replace existing light sources (e.g., incandescent light bulbs).

Disclosure of Invention

In one aspect of the invention, a lighting apparatus includes a light fixture having an opening; at least one LED positioned within the light fixture to emit light through the opening; and a solid state fan located within the light fixture to directly cool the at least one LED.

In another aspect of the invention, a lighting device includes at least one LED configured to emit light; a light fixture containing the at least one LED, wherein the light fixture comprises an opening configured to pass light emitted from the at least one LED; and a solid state fan located within the light fixture to directly cool the at least one LED.

In another aspect of the invention, a lighting apparatus includes a light fixture having an opening; at least one LED positioned within the light fixture to emit light through the opening, wherein the at least one LED is not in thermal contact with the heat sink; and a solid state fan located within the light fixture to cool the at least one LED.

In another aspect of the invention, a lighting apparatus includes a light fixture having an opening; at least one LED positioned within the light fixture to emit light through the opening; and a fan located within the light fixture to directly cool the at least one LED, wherein the fan includes no moving parts.

It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein only exemplary constructions of the LED lamp are shown and described by way of illustration. As will be realized, the invention is capable of other and different aspects and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Drawings

Aspects of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which:

FIG. 1 is a conceptual cross-sectional view showing one example of an LED;

fig. 2 is a conceptual sectional view showing one example of an LED having a phosphor layer;

FIG. 3A is a conceptual top view showing one example of an LED array;

FIG. 3B is a conceptual cross-sectional view of the LED array of FIG. 3A;

FIG. 4A is a conceptual top view showing one example of an alternative configuration of an LED array;

FIG. 4B is a conceptual cross-sectional view of the LED array of FIG. 4A;

FIG. 5 is a conceptual side view of an LED lighting apparatus; and

fig. 6 is a conceptual side view for recessed lighting applications.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which aspects of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the aspects of the invention set forth herein. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The various aspects of the invention illustrated in the drawings may not be drawn to scale. Thus, the dimensions of various features may be expanded or reduced for clarity. In addition, some of the drawings may be simplified for clarity. Accordingly, the drawings may not depict all of the components of a given apparatus (e.g., device) or method.

Aspects of the invention will be described herein with reference to the accompanying drawings, which are schematic illustrations of idealized configurations of the invention. It follows that the results are expected to be a variation from the exemplified shapes, e.g., manufacturing techniques and/or tolerances. Thus, aspects of the invention described throughout this disclosure should not be construed as limited to the particular shapes of elements (e.g., regions, layers, portions, substrates, etc.) shown and described herein but are to include deviations in shapes that result, for example, from manufacturing. By way of example, elements illustrated or described as rectangles may have rounded or curved features and/or have a gradient concentration at their edges, rather than a discrete change from one element to another. Thus, the elements shown in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of an element and are not intended to limit the scope of the present invention.

It will be understood that when an element such as a region, layer, portion, substrate, or the like is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. It will be further understood that when an element is referred to as being "formed" on another element, it can be grown, placed, etched, attached, connected, coupled, or otherwise prepared or fabricated on the other element or intervening elements.

Also, relational terms (e.g., "lower" or "bottom" and "upper" or "top") may be used herein to describe one element's relationship to another element (as illustrated in the figures). It will be understood that relational terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. By way of example, if the device in the figures is turned over, elements described as being on the "lower" side of other elements would then be on the "upper" side of the other elements. Thus, the term "lower" may encompass both an orientation of "lower" and "upper" depending on the particular orientation of the device. Similarly, if the device in the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. Thus, the terms "below" or "beneath" may encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term "and/or" includes any and all combinations of one or more of the associated listed items.

Aspects of the LED lighting device will now be described. However, as those skilled in the art will readily appreciate, these aspects may be extended to a number of aspects of LED lighting devices without departing from the present invention. The LED lighting apparatus may be configured as a direct replacement for conventional light sources including, by way of example, recessed lamps, surface mounted line lamps, pendant lamps, candlesticks, cove lights, track lights, closet lights, landscape or outdoor lights, floodlights, searchlights, street lights, flashlights, industrial lights, strip lights, industrial lights, emergency lights, boom lights, accent lights, background lights, and other light fixtures.

As used herein, the term "luminaire" shall denote a light fixture with a light source. The term "light fixture" shall include all components of the lighting device other than the light source (e.g., a housing or casing, a fan for cooling the light source, a mirror for directing light, etc.). The term "LED lighting device" shall denote a lighting device having a light source comprising one or more LEDs. LEDs are well known in the art and will only be discussed briefly to provide a thorough description of the present invention.

Fig. 1 is a conceptual sectional view showing one example of an LED. LEDs are semiconductor materials that are implanted or doped with impurities. These impurities add "electrons" and "holes" to the semiconductor, which can move relatively freely in the material. The doped region of the semiconductor may have mainly electrons or holes depending on the impurity species, and is referred to as an n-type or p-type semiconductor region, respectively. Referring to fig. 1, the LED100 includes an n-type semiconductor region 104 and a p-type semiconductor region 108. A reverse electric field is generated at the junction between the two regions that move electrons and holes away from the junction to form active region 106. When a forward voltage sufficient to overcome the reverse electric field is applied across the p-n junction through a pair of electrodes 110, 112, electrons and holes are forced into the active region 106 and recombine. When the electrons recombine with holes, they drop to a low energy level and release energy in the form of light.

In this example, the n-type semiconductor region 104 is formed on the substrate 102 and the p-type semiconductor region 108 is formed on the active layer 106, however, the regions may be reversed. That is, the p-type semiconductor region 108 may be formed on the substrate 102 and the n-type semiconductor region 104 may be formed on the active layer 106. As those skilled in the art will readily appreciate, the various concepts described throughout this disclosure may be extended to any suitable layered structure. Additional layers or regions (not shown) may also be included in the LED100, including but not limited to buffer, nucleation, contact and current spreading layers or regions, and light extraction layers. The P-type semiconductor region 108 is exposed at the top surface, and thus, the P-type electrode 112 can be easily formed thereon. However, the n-type semiconductor region 104 is buried under the p-type semiconductor layer 108 and the active layer 106. Thus, to form the n-type electrode 110 on the n-type semiconductor region 104, a cutout region or "mesa" is formed by removing a portion of the active layer 106 and the p-type semiconductor region 108 using methods well known in the art. After removing the portion, the n-type electrode 110 may be formed.

Fig. 2 is a conceptual sectional view showing one example of an LED having a phosphor layer. In this example, a phosphor layer 202 is formed on the top surface of the LED100 by methods well known in the art. The phosphor layer 202 converts a portion of the light emitted by the LED100 to light having a different spectrum from the light emitted from the LED 100. A white LED light source may be constructed by using an LED that emits light in the blue region of the spectrum and a phosphor that converts the blue light to yellow light. White light sources are suitable for use as replacement lamps for conventional lighting devices; however, the invention can be practiced with other LED and phosphor combinations to produce different colors of light. By way of example, the phosphor layer 202 may include phosphor particles suspended in a carrier of multiple or different phosphor species, or composed of soluble phosphors that decompose in the carrier.

In the construction of LED lighting devices, an array of LEDs may be used to provide increased light. Fig. 3A is a conceptual top view showing one example of an LED array, and fig. 3B is a conceptual cross-sectional view of the LED array in fig. 3A. In this example, a plurality of phosphor coated LEDs 200 may be formed on a substrate 302 by methods well known in the art. Bond wires (not shown) extending from the LEDs 200 may be connected to traces (not shown) on the surface of the substrate 302 that connect the LEDs 200 in parallel and/or in series or series-parallel. In general, the LEDs 200 may be connected in parallel streams of series LEDs with a current limiting resistor (not shown) in each stream. Substrate 302 may be any suitable material that may provide support to LED200 and may be mounted within a light fixture (not shown).

Fig. 4A is a conceptual top view showing one example of an alternative configuration of an LED array, and fig. 4B is a conceptual sectional view showing the LED array in fig. 4A. A substrate 302 designed for mounting in a light fixture (not shown) may be used to support an array of LEDs 100 in a manner similar to that described in connection with fig. 3A and 3B. However, in this configuration, the phosphor layer is not formed on each individual LED. Instead, the phosphor 406 is disposed within the cavity 402, the cavity 402 being bounded by an annular ring 404 extending circumferentially around the outer surface of the substrate 302. The annular ring 404 may be formed by drilling a cylindrical hole in the material forming the substrate 302. Alternatively, the substrate 302 and annular ring 404 may be formed using a suitable template, or the annular ring 404 may be formed separately from the substrate 302 and attached to the substrate using an adhesive or other suitable method. In the latter configuration, the annular ring 404 is typically attached to the substrate 302 before the LED100, but in some configurations, the LED400 may be attached first. Once the LEDs 100 and annular ring 404 are attached to the substrate 302, a suspension of phosphor particles in a carrier can be introduced into the cavity 402. The carrier material may be an epoxy or silicone; however, carriers based on other materials may also be used. The carrier material may be cured to produce a solid material that immobilizes the phosphor particles.

Fig. 5 is a conceptual side view of an LED lighting device. The LED luminaire may include a light fixture 500, which may include a housing 502 made of a thermally conductive material, such as aluminum. The housing 502 is shown with a cylindrical shape for recessed lighting applications, but may be configured for other lighting applications, such as surface mount lights, ceiling lights, candlesticks, recessed troffer lights, overhead projector lights, closet lights, landscape or outdoor lights, street lights, industrial lights, emergency lights, desk lights, background lights, and other light fixtures. Those skilled in the art will be readily able to determine the appropriate configuration of the shell for any particular application.

An LED array 504 is located within the light fixture 502. The LED array 504 may take a variety of forms, including any of the configurations discussed earlier in connection with fig. 2-4, or any other suitable configuration now known or later developed. Although an LED array is suitable for an LED lighting device, those skilled in the art will readily appreciate that the various concepts presented throughout this disclosure are not necessarily limited to arrays, and may be extended to LED lighting devices having a single LED light source.

The light fixture 500 includes a base 506 for supporting a light source. The base 506 may be an integral part of the housing 502 or attached by any suitable method. A plate 508 secured to a base 506 carries the LED array 504. In one configuration of the LED lighting device, standoffs 510 extending from the plate 508 are used to separate the LED array 504 from the plate 508. This configuration provides a means for mounting a fan 512 near the LED array 504. The standoffs 510 may be non-conductive (e.g., plastic, ceramic) standoffs having tapered heads that may pass through holes in the substrate of the LED array 504. Alternatively, the standoff 510 may be glued to the LED array 504, or alternatively, may include internal threads that allow the LED array 504 to be mounted with screws. Other ways of mounting the LED array 504 will be apparent to those skilled in the art in light of the teachings set forth throughout this disclosure. The plate 508 may be constructed of any suitable insulating material including, by way of example, plastic, cardboard, or the like.

The fan 512 may be a solid state fan. Solid state fans are devices used to generate airflow without moving parts. Basically, solid state fans use the charge on a conductor to ionize air, which results in ionized air molecules having the same polarity as the charge on the conductor. The electrodes repel the same charge of ionic molecules to produce an electric or ionic wind. A non-limiting example of a solid state fan is the RSD5 solid state fan developed by Thorrn Micro Technologies, Inc. RSD5 uses a series of energized wires that generate an ion enriched gas using free electrons for conduction. The wires are located within uncharged conductive plates that are contoured in a semi-cylindrical shape to partially cover the wires. Within the generated electric field, the ions push neutral air molecules from the wire to the plate, creating an air flow.

The positioning of the fan 512 on the board 508 provides a means for directly cooling the LED array 504, thereby eliminating the need for a heat sink. As used herein, "direct" cooling refers to positioning the LED array 504 within the air flow generated by the fan 512. In contrast, an LED array that is "indirectly" cooled by a fan means that a thermally conductive material attached to the LED array is disposed within the air flow generated by the fan. By way of example, a fan for cooling a heat sink for the LED array would be a form of indirect cooling. Although the fan 512 is mounted directly over the LED array 504, the fan 512 may be located elsewhere in the light fixture 500 and still provide direct cooling of the LED array 504. One skilled in the art will be readily able to determine the location of the fan 512 and LED array 504 that is best suited for any particular application based on all design parameters.

The light fixture 500 may include small apertures for routing wires 516a and 516b from a power source (not shown) to the LED array 504 and the fan 512. In one configuration of the LED lighting device, the wires 516a and 516b may be routed from the power source to the LED array 504 through the plastic hollow standoffs 510 described previously. An AC-DC converter (not shown) may be used to generate a DC voltage from an AC power source typically found in a home, office building, or other facility. The DC voltage generated by the AC-DC converter may be provided to a driver circuit (not shown) configured to drive both the LED array 504 and the fan 512. The AC-DC converter and drive circuitry may be located on the board 508, on the LED array 504, or anywhere else in the light fixture 500. In some applications, an AC-DC converter may not be required. By way of example, the LED array 504 and fan 512 may be designed for AC power. Alternatively, the power supply may be DC, as may be the case in automotive applications. The specific design of the power transfer circuit for any particular application is within the ability of those skilled in the art.

The light fixture 500 may take a variety of forms depending on the particular application. In recessed lighting applications, for example, the light fixture 500 may be an Insulated Contact (IC) or a non-insulated contact design. One example of a light fixture 602 for IC applications in recessed ceilings is shown in fig. 6. Light fixture 602 is configured with a housing 602a and an inner wall 602 b. The inner wall 602b acts as a heat sink for the LED array 504. The fan 512 is located in the inner wall 602b in the vicinity of the vent 614, which causes air to flow into the gap between the two walls 602a, 602 b. The air flow thermally insulates the outer shell 602a from the heated inner wall 602b, thereby protecting the insulation and other materials in the ceiling from heat and undesirable air flow.

Various aspects of the invention are provided to enable those skilled in the art to practice the invention. Various modifications to the aspects set forth throughout this disclosure will be readily apparent to those skilled in the art, and the concepts disclosed herein may be extended to other LED lamp configurations, regardless of the shape or diameter of the glass envelope and base, and the configuration of the electrical contacts on the lamp. Thus, the claims are not intended to be limited to the aspects of the disclosure, but is to be accorded the full scope consistent with the language claims. All structural and functional equivalents that are known or later come to be known to those of ordinary skill in the art to which elements of the various aspects described throughout this disclosure are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. Unless the phrase "means for … …" is used to specifically recite an element (or, in the case of method claims, the phrase "step for … …" is used to recite an element), no claim element is to be construed under the provisions of 35 u.s.c § 112, paragraph six.

Claims (64)

1. An illumination device, comprising:

a light fixture having an opening; and

at least one LED positioned within the light fixture to emit light through the opening;

wherein the light fixture further comprises a solid state fan positioned to directly cool the at least one LED.

2. The lighting device of claim 1, wherein the at least one LED comprises an array of LEDs.

3. The lighting device of claim 1, further comprising phosphor, wherein each of the one LED is disposed to emit light through the phosphor.

4. The luminaire of claim 3 wherein said phosphor comprises a phosphor layer on each of said at least one LED.

5. The luminaire of claim 3 further comprising a substrate having a cavity, wherein the at least one LED and the phosphor are in the cavity.

6. The lighting device of claim 1, further comprising a plate supporting the at least one LED and the fan.

7. The luminaire of claim 6 further comprising a base attached to the light fixture, wherein the base supports the plate.

8. The lighting device of claim 6, wherein the plate provides a through hole for coupling wires to the at least one LED and the fan.

9. The lighting device of claim 6, wherein the at least one LED is supported by the board by a plurality of hollow standoffs, and wherein the at least one LED comprises wires for coupling to a power source, each of the wires passing through one of the standoffs.

10. The luminaire of claim 1 further comprising a lens covering the opening in the light fixture.

11. The luminaire of claim 1 wherein the light fixture comprises a recessed light fixture.

12. The luminaire of claim 11 wherein the recessed light fixture is configured for an insulated ceiling or wall.

13. The luminaire of claim 11 wherein the recessed light fixture is configured for a non-insulated ceiling or wall.

14. The luminaire of claim 1 wherein the light fixture includes an air flow channel formed between an outer wall and an inner wall.

15. The luminaire of claim 1 wherein the light fixture comprises a vent.

16. The luminaire of claim 1 wherein the light fixture is configured to be attached into a track in a track lighting configuration.

17. An illumination device, comprising:

at least one LED configured to emit light;

a light fixture containing the at least one LED, wherein the light fixture comprises an opening configured to pass the light emitted from the at least one LED; and

a solid state fan located within the light fixture to directly cool the at least one LED.

18. The lighting device of claim 17, wherein the at least one LED comprises an array of LEDs.

19. The lighting device of claim 17, further comprising phosphor, wherein each of the one LED is configured to emit light through the phosphor.

20. The luminaire of claim 19 wherein the phosphor comprises a phosphor layer on each of the at least one LED.

21. The luminaire of claim 19 further comprising a substrate having a cavity, wherein the at least one LED and the phosphor are in the cavity.

22. The lighting device of claim 17, further comprising a plate supporting the at least one LED and the fan.

23. The luminaire of claim 22 further comprising a base attached to the light fixture, wherein the base supports the plate.

24. The lighting device of claim 22, wherein the plate provides a through hole for coupling wires to the at least one LED and the fan.

25. The lighting device of claim 22, wherein said at least one LED is supported by said plate by a plurality of hollow standoffs, and wherein said at least one LED comprises wires for coupling to a power source, each said wire passing through one said standoff.

26. The luminaire of claim 17 further comprising a lens covering the opening in the light fixture.

27. The luminaire of claim 17 wherein the light fixture comprises a recessed light fixture.

28. The luminaire of claim 27 wherein the recessed light fixture is configured for an insulated ceiling or wall.

29. The luminaire of claim 27 wherein the recessed light fixture is configured for a non-insulated ceiling or wall.

30. The luminaire of claim 17 wherein the light fixture includes an air flow channel formed between an outer wall and an inner wall.

31. The luminaire of claim 17 wherein the light fixture comprises a vent.

32. The luminaire of claim 17 wherein the light fixture is configured to be attached into a track in a track lighting configuration.

33. An illumination device, comprising:

a light fixture having an opening;

at least one LED positioned within the light fixture to emit light through the opening, wherein the at least one LED is not in thermal contact with the heat sink; and

a solid state fan located within the light fixture to cool the at least one LED.

34. The lighting device of claim 33, wherein the at least one LED comprises an array of LEDs.

35. The lighting device of claim 33, further comprising phosphor, wherein each of the one LED is configured to emit light through the phosphor.

36. The luminaire of claim 35 wherein said phosphor comprises a phosphor layer on each of said at least one LED.

37. The luminaire of claim 35 further comprising a substrate having a cavity, wherein the at least one LED and the phosphor are in the cavity.

38. The lighting device of claim 33, further comprising a plate supporting the at least one LED and the fan.

39. The luminaire of claim 38 further comprising a base attached to the light fixture, wherein the base supports the plate.

40. The lighting device of claim 38, wherein the plate provides a through hole for coupling wires to the at least one LED and the fan.

41. The lighting device of claim 38, wherein said at least one LED is supported by said plate by a plurality of hollow standoffs, and wherein said at least one LED comprises wires for coupling to a power source, each said wire passing through one said standoff.

42. The luminaire of claim 33 further comprising a lens covering the opening in the light fixture.

43. The luminaire of claim 33 wherein the light fixture comprises a recessed light fixture.

44. The luminaire of claim 43 wherein the recessed light fixture is configured for an insulated ceiling or wall.

45. The luminaire of claim 43 wherein the recessed light fixture is configured for a non-insulated ceiling or wall.

46. The luminaire of claim 33 wherein the light fixture includes an air flow channel formed between an outer wall and an inner wall.

47. The luminaire of claim 33 wherein the light fixture comprises a vent.

48. The luminaire of claim 33 wherein the light fixture is configured to be attached into a track in a track lighting configuration.

49. An illumination device, comprising:

a light fixture having an opening;

at least one LED positioned within the light fixture to emit light through the opening; and

a fan located within the light fixture to directly cool the at least one LED, wherein the fan does not include moving parts.

50. The lighting device of claim 49, wherein said at least one LED comprises an array of LEDs.

51. The luminaire of claim 49 further comprising phosphor, wherein each of said one LED is configured to emit light through said phosphor.

52. The luminaire of claim 51 wherein said phosphor comprises a phosphor layer on each of said at least one LED.

53. The luminaire of claim 51 further comprising a substrate having a cavity, wherein the at least one LED and the phosphor are in the cavity.

54. The luminaire of claim 49 further comprising a plate supporting said at least one LED and said fan.

55. The luminaire of claim 54 further comprising a base attached to the light fixture, wherein the base supports the plate.

56. The lighting device of claim 54, wherein the plate provides a through hole for coupling wires to the at least one LED and the fan.

57. The lighting device of claim 54, wherein said at least one LED is supported by said plate by a plurality of hollow standoffs, and wherein said at least one LED comprises wires for coupling to a power source, each said wire passing through one said standoff.

58. The luminaire of claim 49 further comprising a lens covering the opening in the light fixture.

59. The luminaire of claim 49 wherein the light fixture comprises a recessed light fixture.

60. The luminaire of claim 59 wherein the recessed light fixture is configured for an insulated ceiling or wall.

61. The luminaire of claim 59 wherein the recessed light fixture is configured for a non-insulated ceiling or wall.

62. The luminaire of claim 49 wherein the light fixture includes an air flow channel formed between an outer wall and an inner wall.

63. The luminaire of claim 49 wherein the light fixture comprises a vent.

64. The luminaire of claim 49 wherein the light fixture is configured to be attached into a track in a track lighting configuration.