WO2011137384A2

WO2011137384A2 - A modular high power led light design

Info

Publication number: WO2011137384A2
Application number: PCT/US2011/034639
Authority: WO
Inventors: Heng FANG; Xiaoming Zheng
Original assignee: Uniflux Led, Inc.
Priority date: 2010-04-30
Filing date: 2011-04-29
Publication date: 2011-11-03
Also published as: WO2011137384A3; WO2011137364A2

Abstract

A modular lighting device. The modular lighting device includes two or more LED modules. Each LED module further including a printed circuit board (PCB) and multiple LEDs mounted on a first face of the PCB. A heat sink is mounted on a second face of the PCB. Further, the modular lighting device includes a power supply. The two or more LED modules are coupled to each other.

Description

A MODULAR HIGH POWER LED LIGHT DESIGN

TECHNICAL FIELD

[0001] The present disclosure relates generally to lighting devices, and more particularly to light emitting diode (LED) lighting devices.

BACKGROUND

[0002] Light emitting diodes (LEDs) are increasingly used these days to replace conventional lighting devices. Because of their small size, low power consumption, and long life, LEDs are applied to various display applications. These lighting devices, however, have one drawback - they generate excessive heat, and if the heat is not dissipated efficiently, the LED's efficiency and lifetime may be limited.

[0003] Typically, heat sinks or cooling fins are attached to the back-end or non-emitting surface of the LEDs to dissipate the heat. For large or high-power lighting systems with numerous LEDs, these existing heat controlling techniques, however, have some limitations. For example, large lighting devices typically include a light board or a printed circuit board (PCB) with multiple LEDs mounted on a first side, heat sinks mounted on a second side, an outer case, a cover, and a single power supply that powers all the LEDs. Moreover as all the LEDs are mounted on a single PCB, the heat sinks corresponding to the LEDs at the center of the PCB board are surrounded by other heat sinks. These central heat sinks find it harder to dissipate heat than the heat sinks at the board's edges. This uneven heat dissipation leads to uneven LED junction temperatures (the LEDs in the center are hotter than the LEDs at the board's edges), which in turn affects the LEDs' life.

[0004] Moreover, when more and more LEDs are connected in serial or in parallel, the electric current passing through these LEDs differs due to natural variations in the LEDs' characteristics. As a result, some LEDs bear higher power than the rest, which affects the overall life and working efficiency of the LED.

[0005] In addition, present lighting systems cannot dissipate heat from the back-end of the lighting device to the front. So when these lighting systems are mounted on walls, the central LEDs get still hotter. Therefore, there exists a need for an LED lighting system that overcomes at least one drawback described in the previous paragraphs.

SUMMARY

[0006] Embodiments of the present disclosure are directed to a modular lighting device. One such embodiment describes a lighting device including two or more LED modules. Each LED module includes a printed circuit board (PCB) with multiple LEDs mounted on a first face of the PCB. A heat sink is mounted on a second face of the PCB. Each LED module further includes independent power supply. Moreover, the two or more LED modules of the lighting device are coupled to each other.

[0007] Another embodiment of the present disclosure describes a modular lighting device. The lighting device comprises two or more LED modules. Each LED module has a first face and a second face, and the first face of the two or more LED modules are aligned in one plane. A connecting rod passes through the sides of the two or more LED modules to connect them. Further, a support structure engages the connecting rod.

[0008] Certain embodiments of the disclosure may provide various technical advantages.

For example, certain embodiments may produce constant and consistent LED junction temperatures for all the LEDs of the lighting device. Further, other embodiments of the system may provide approximately equal current to the LEDs of the lighting device, thereby providing equal power.

[0009] These and other aspects, features, and benefits of the present disclosure will become apparent from the following detailed written description of the preferred embodiments and aspects taken in conjunction with the following drawings, although variations and modifications thereto may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings illustrate one or more embodiments and/or aspects of the disclosure and, together with the written description, serve to explain the principles of the disclosure. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment. The drawings are illustrative in nature and are not necessarily drawn to scale.

[0011] FIG. 1 is a front view of a lighting device according to embodiments of the present disclosure.

[0012] FIG.2 is a side view of the lighting device illustrated in FIG. 1

[0013] FIG. 3 illustrates an alternative lighting device according to embodiments of the present disclosure.

[0014] FIG. 4 illustrates an exemplary lighting device according to embodiments of the present disclosure.

[0015] FIG. 5 illustrates an exemplary lighting device according to embodiments of the present disclosure.

DETAILED DESCRIPTION

[0016] To promote an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will, nevertheless, be understood that no limitation of the scope of the disclosure is thereby intended; any alterations and further modifications of the described or illustrated embodiments and any further applications of the principles of the disclosure as illustrated therein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. All limitations of scope should be determined in accordance with and as expressed in the claims.

[0017] As described here, the terms "bottom" and "top" imply the bottom and top portions of the described element as illustrated in the figures only. These terms do not refer to the bottom and top positions of the actual lighting device. If the device is inverted, these terms may be interchangeably used.

Overview

[0018] Embodiments of the present disclosure describe a modular LED lighting device.

The modular lighting device includes multiple LED modules, with each module including multiple LEDs. The LEDs on one module are connected to one another, but disjoined from the LEDs on a second module. Because of this disconnect between the modules, power is supplied independently to each module. With independent power supply, power applied to LEDs on one module does not depend on the variations in characteristics of LEDs on another module, reducing the overall power variation of the lighting device.

Exemplary Embodiments

[0019] FIG. 1 and FIG. 2 illustrate a front view and a side view of an exemplary lighting device 100, respectively. The lighting device 100 includes multiple LED light modules 102 placed side-by-side with their LED faces aligned in one plane. The modules 102 are connected to one another through connecting rods 103 and 104 and the entire structure is mounted on a support structure 105. Each LED module 102 is an independent lighting system with its own printed circuit board (PCB) 106, heat sinks 107, and power supply 108. LEDs 109 are mounted on one face of the PCB 106 and the heat sinks 107 are mounted on the opposite face.

[0020] Heat sinks 107 absorb heat from the LEDs 109 and dissipate this heat into the atmosphere, lowering the junction temperature of the corresponding LED 109. Any heat sink may be employed in this lighting device 100 without departing from the scope of the present disclosure. For example, pin type, straight or flared fin type heat sinks may be employed. In this exemplary embodiment, straight fin heat sinks are utilized.

[0021] As described previously, each LED module 102 may include multiple LEDs 109. Further, these LEDs 109 may be positioned in any fashion without departing from the scope of the present disclosure. For example, the LEDs 109 may be positioned in a single line, in two lines, in a particular pattern, or randomly. Moreover, the LEDs 109 of a particular module may be connected in series or in parallel. Power connections for the modules 102 may be pulled out from the module casing and connected to an external power supply. With individual power connections to each module 102, power is independently supplied to the modules 102.

Alternatively, a power supply 108 may be mounted on each LED module 102.

[0022] Connecting rods 103 and 104 pass through the breadth of the modules 102 at approximately their center portion and bottom portion, respectively. To this end, the modules 102 may include tubular cavities along their breadth. The connecting rods 103, 104 fit through these cavities. To snugly fit the connecting rods 103, 104, compliant sleeves may be added to the cavities. It will be understood that other fitting means may be contemplated and those means are well within the scope of the present disclosure. Further, the ends of the connecting rods 103, 104 may extend out from the first and last LED modules (such as module 102-A and 102-D). It will be understood that the connecting rods 103, 104 and the tubular cavities may have any cross-sectional shape. For example, the cross sections of the tubular cavity and the connecting rods may be circular, elliptical, polygonal, or triangular.

[0023] The support structure 105 includes a base 110, two prongs 112-A, 112-B extending perpendicularly from the two ends of the base 110, and a stand 114. The base 110 may be approximately as wide as the width of the modules 102 side-by-side. To connect the support structure to the modules, it may include one or more connecting means. For example, the prongs 112 may have cavities 202, 204 (illustrated in FIG. 2) of approximately the same dimensions as the connecting rods 103, 104 and at approximately the same distance from each other as the distance between the connecting rods 103, 104. Then, the cavities 202, 204 engage with the extending connecting rods 103, 104, connecting the support structure 105 to the modules 102. A fastener 116 may fix the support structure 105 to the connecting rods.

Examples of fasteners may include screws, bolts, nuts, welds, and so on. It will be understood that other known connecting means may also be contemplated without departing from the scope of the present disclosure. For instance, the prongs may include protrusions extending perpendicularly from the inner face of the prong. These protrusions may be aligned with apertures or cavities in the connecting rods 103, 104.

[0024] FIG. 2 illustrates the side view of support 105. Here the prongs 112 taper from the base 110 to the top. Angular movement is useful in focusing light at a certain angle, for example to point the lighting device 100 at a painting, at players in a stadium, and so on. To this end, the support structure includes a pivotable section in the form of an arcuate lower cavity 204 extending along the face of the prong 112. This feature aids in rotating the modules 102 around the bottom connecting rod 104. The shape and curve of the lower cavity 204 may determine the degree of rotation.

[0025] The lighting device's modularity helps maintain an even junction temperature across the LEDs 109 and also provides uniform power to them. To increase the lighting device's dissipative power, ventilating gaps 118 may be maintained between two adjacent LED modules 102. The gaps 118 allow cool air to travel from the front to the back (cooling the heat sinks 107) and hot air from the back to the front, allowing the heat sinks 107 to dissipate heat to a larger volume. Any suitable gap 118 may be maintained, depending on the module size and the required lighting device size. In one embodiment, an 8 mm gap may be maintained between the modules 102. To maintain the required gap 118, the connecting rods 103, 104 may include retention members. These retention members may be an integral part of the connecting rods 103, 104 or may be added later, during assembly. Some examples of retention members may include barbs extending from the connecting rods, stoppers, washers, or bushing. It will be appreciated that numerous other retention techniques are possible and any of these techniques may be utilized to maintain the gap 118 between the modules 102.

[0026] FIGS. 1 and 2 illustrate one exemplary embodiment of the modular lighting device 100. It will be understood that numerous other embodiments are possible and within the scope of the present disclosure. A few alternative embodiments will be described in the following sections. FIG. 3 illustrates another exemplary embodiment of the lighting device. Here, only one connecting rod 103 (approximately at the longitudinal center of the modules 102) connects the modules 102 together. In this embodiment, the rod 103 may be tightly fit into the modules' cavities so that the modules 102 do not rotate about the connecting rod 103.

Alternatively, if rotation is required, the connecting rod 103 may be fixed in such a manner to allow angular movement of the modules 102 about the rod 103. Moreover, the support structure 105 depicted in FIGS. 1 and 2 or any other support structure may be employed with the lighting system illustrated in FIG. 3.

[0027] In yet another embodiment, modules 102 may include tubular engaging apertures

402 on their side faces. FIG. 4 is an exploded view of such an arrangement 400. Unlike the tubular cavities of the exemplary lighting device 100, the apertures 402 do not extend all the way through the modules 102. Instead, these apertures 402 extend up to a certain depth. Moreover, the apertures 402 may be present on both side faces of the modules 102 at approximately the same height. Dowels 404 of suitable cross-section may be utilized to connect the modules 102 in pairs. The dowels 404 may be screw fit, snap fit, or welded to the apertures 402. To add modules to this assembly, additional dowels 404 may be utilized. A support structure similar to the support 105 illustrated in FIGS. 1 and 2 may be utilized here as well. Further, the length of the dowels 404 may determine the gap width between the modules 102, if any. For example, longer dowels 404 may be utilized to maintain a larger gap 118 and shorter dowels 404 may be utilized to reduce or eliminate the gap 118.

[0028] In another exemplary embodiment, the modules 102 may be coupled to each other using a frame structure. FIG. 5 illustrates such as embodiment. Here, the top end 502 and the bottom end 504 of the modules 102 may fit into a frame, such as frame 506. Connecting members 508 present in the frame 506 engage the modules 102. In one embodiment, the connecting members 508 may swivel about their axes, which in turn allow rotation of the modules 102 along their longitudinal axes. Moreover, the connecting rods may include means to fix the modules at a certain angle. These means may include stoppers or locking mechanisms widely known in the art. Power connection may be provided to the modules 102 through the connecting members 508. Further, to maintain gaps 118 between the modules 102, the connecting members 508 may be placed at a distance greater than the breadth of the modules 102. In this arrangement, a support structure 105 may also be incorporated. The support may include a stand 114 temporarily or permanently connected to the frame 500. Further, the stand may be connected on any side of the frame 500. For example, in certain applications the modules may be aligned horizontally, while in others, vertically. Depending on the application, the stand 114 may be fixed on the length of the frame 500 generally indicated at point 510, or on the breadth of the frame 500, generally indicated at point 512.

[0029] In the figures depicted in this disclosure, the modules are represented as generally rectangular structures. It will be understood, however, that this geometrical shape is merely exemplary and the modules may be shaped in any desired fashions without departing from the scope of the present disclosure. For example, in some embodiments, the modules 102 may have a generally circular, triangular, polygonal, or random shape. Moreover, it will be appreciated that the module size and the number of LEDs per module may vary in a given lighting device 100. In one preferred embodiment, there are no more than 50 LEDs per module, and no more than 6 modules coupled to each other; in yet another preferred embodiment, there are no more than 30 LEDs per module, and no more than 5 modules coupled to each other; in another further preferred embodiment, there are no more than 20 LEDs per module, and no more than 4 modules coupled to each other. When excessive numbers of LEDs are clustered in a module, and/or excessive numbers of modules are coupled together, the original purpose and intent of this invention becomes more difficult to achieve. It will also be understood that the coupling techniques described here are merely exemplary. Any other technique now known or contemplated in the future may be utilized to connect the modules 102 to each other. A support structure 105 or a stand 114 may be incorporated in the lighting devices to provide support. In some applications, however, the support structure 105 may not be required. In these

applications, no support structure is provided.

[0030] In one embodiment, twenty 3-watt LEDs may be mounted per module, and the lighting device may include four such LED modules. With this structure, the lighting device consumes 240 watts of power producing a luminous flux of 19000 Lm.

[0031] The specification has set out a number of specific exemplary embodiments, but those skilled in the art will understand that variations in these embodiments will naturally occur in the course of embodying the subject matter of the disclosure in specific implementations and environments. It will further be understood that such variation and others as well, fall within the scope of the disclosure. Neither those possible variations nor the specific examples set above are set out to limit the scope of the disclosure. Rather, the scope of the present disclosure is defined solely by the claims set out below.

Claims

CLAIMS What is claimed is:

1. A lighting device, comprising:

two or more LED modules, each LED module comprising:

a printed circuit board (PCB);

multiple LEDs mounted on a first face of the PCB;

a heat sink mounted on a second face of the PCB; and

a power supply; and

wherein the LED modules are coupled to one another.

2. The lighting device of claim 1 further comprising a support structure connected to the LED modules.

3. The lighting device of claim 1, wherein the two or more LED modules are separated by a ventilation gap.

4. The lighting device of claim 3, wherein the ventilation gap between the two or more LED modules is 8 mm wide.

5. The lighting device of claim 1, wherein each of the two or more LED modules includes twenty 3- watt white LEDs.

6. The lighting device of claim 1 including four LED modules.

7. The LED lighting device of claim 6, wherein the luminous flux of the lighting device is approximately 19000 Lm.

8. The LED lighting device of claim 1, wherein the LEDs are high-power LEDs.

9. A modular lighting device, comprising:

two or more LED modules, each with a first face and a second face, the first face of the two or more modules being aligned in one plane;

a first connecting rod passing through the sides of the two or more LED modules to connect them; and

a support structure engaging the connecting rod.

10. The modular lighting device of claim 9, wherein each LED module comprises:

a printed circuit board (PCB);

multiple LEDs mounted on a first face of the PCB;

a heat sink mounted on a second face of the PCB; and

a power supply.

11. The modular lighting device of claim 9, wherein the support structure includes a pivotable section allowing angular movement of the LED modules about the connecting rod.

12. The modular lighting device of claim 9, wherein the connecting rod passes through the sides of the two or more LED modules approximately near the longitudinal center of the modules, the ends of the connecting rod extending out from the outermost LED modules.

13. The modular lighting device of claim 12, further comprising a second connecting rod passing through the sides of the two or more LED modules at approximately a bottom portion of the LED modules, the ends of the second connecting rod extending out from the outermost LED modules.

14. The modular lighting device of claim 13, wherein the support structure includes connecting means to engage the portions of the first connecting rod and the second connecting rod extending from the outermost LED modules.

15. The modular lighting device of claim 9, wherein the two or more LED modules are separated by a ventilation gap.

16. The modular lighting device of claim 15, wherein the ventilation gap between the two or more LED modules is 8 mm wide.

17. The modular lighting device of claim 9, wherein each LED module includes twenty 3- watt white LEDs.

18. The modular lighting device of claim 17 including four LED modules.

19. The modular lighting device of claim 18, wherein the luminous flux of the lighting device is approximately 19000 Lm.

20. The modular lighting device of claim 9, wherein the LEDs are high-power LEDs.