RELAMPABLE LED STRUCTURE
A lighting assembly includes a plurality of LEDs mounted on a flexible substrate such as a printed circuit board. The printed circuit board is bonded thermally and physically to a thicker, rigid substrate, such as a metal plate, to form a board assembly. The rigid substrate is made of a thermally conductive material, such as aluminum. As such, the board assembly provides structural rigidity and thermal conductance. Bonding the metal plate to the printed circuit board also provides improved thermal communication over the entire overlapping areas of the metal plate and printed circuit board. The board assembly is fastened to a heat exchanging device, such as an evaporator. The rigid substrate of the board assembly provides continuous contact of the substrate with the heat exchanging device in response to a reduced number of fastening points.
This Patent Application claims priority under 35 U.S.C. 119 (e) of the co-pending U.S. provisional application Ser. No. 61/665,179, filed Jun. 27, 2012, and entitled “LED LIGHTING” and U.S. provisional application Ser. No. 61/673,660, filed Jul. 19, 2012, and entitled “HIGH BAY LED LIGHTING AND HEAT DISSIPATION”, both by these same inventors. This application incorporates U.S. provisional application Ser. No. 61/665,179 and U.S. provisional application Ser. No. 61/673,660 in their entireties by reference.
FIELD OF THE INVENTIONThe present invention is generally directed to the field of light emitting diode (LED) lighting. More specifically, the present invention is directed to a LED structured as a replaceable light source.
BACKGROUND OF THE INVENTIONA light-emitting diode (LED) is a semiconductor light source. LEDs are increasingly being used in a wide variety of lighting applications. LEDs continue growing in popularity due in part to their efficiency and extended lifetimes. An LED-based light source typically includes a plurality of individual LEDs mounted on a printed circuit board. Printed circuit boards are flexible substrates.
SUMMARY OF THE INVENTIONA lighting assembly includes a plurality of LEDs mounted on a flexible substrate such as a printed circuit board. The printed circuit board is bonded thermally and physically to a thicker, rigid substrate, such as a metal plate, to form a board assembly. The rigid substrate is made of a thermally conductive material, such as aluminum. As such, the board assembly provides structural rigidity and thermal conductance. Bonding the metal plate to the printed circuit board also provides improved thermal communication over the entire overlapping areas of the metal plate and printed circuit board. The board assembly is fastened to a heat exchanging device, such as an evaporator. Due to the rigid structure, proper thermal communication is established across an entire interface surface of the board assembly and heat exchanging device even though fasteners are only sparsely applied, such as about the perimeter. The rigid substrate of the board assembly provides continuous contact of the substrate with the heat exchanging device in response to a reduced number of fastening points.
In an aspect, a lighting assembly includes a plurality of light emitting diodes, a first substrate and a second substrate. The plurality of light emitting diodes are electrically and mechanically coupled to the first substrate. The second substrate is thermally and mechanically coupled to the first substrate, wherein the second substrate is rigid and is made of thermally conductive material. In some embodiments, the first substrate is a printed circuit board. In some embodiments, the second substrate is a metal plate. In some embodiments, the metal plate is made of aluminum. In some embodiments, the second substrate and the first substrate are bonded together.
In another aspect, a lighting assembly includes a plurality of light emitting diodes, a first substrate, a second substrate, a mounting structure and a plurality of fastening devices. The plurality of light emitting diodes are electrically and mechanically coupled to the first substrate. The second substrate is thermally and mechanically coupled to the first substrate, wherein the second substrate is rigid and is made of a thermally conductive material. The second substrate is thermally and mechanically coupled to the mounting structure. The plurality of fastening devices are configured to mechanically couple the second substrate to the mounting structure. In some embodiments, the mounting structure is a heat exchanging device. In some embodiments, the lighting assembly also includes a thermal interface material between the second substrate and the mounting structure. In some embodiments, the thermal interface material is a thermally conductive pad, a thermally conductive epoxy, a thermally conductive grease, or a thermally conductive adhesive. In some embodiments, the plurality of fastening devices are a plurality of screws, a plurality of clamps, a plurality of brackets, or a plurality of quick release latches. In some embodiments, the first substrate is a printed circuit board. In some embodiments, the second substrate is a metal plate. In some embodiments, the metal plate is made of aluminum. In some embodiments, the second substrate and the first substrate are bonded together.
Several example embodiments are described with reference to the drawings, wherein like components are provided with like reference numerals. The example embodiments are intended to illustrate, but not to limit, the invention. The drawings include the following figures:
Embodiments of the present application are directed to a lighting assembly. Those of ordinary skill in the art will realize that the following detailed description of the lighting assembly is illustrative only and is not intended to be in any way limiting. Other embodiments of the lighting assembly will readily suggest themselves to such skilled persons having the benefit of this disclosure.
Reference will now be made in detail to implementations of the lighting assembly as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts. In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application and business related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.
The cooling system is configured to enable the dissipation of a large amount of energy in the form of heat without heating surrounding components, such as the one or more power supply units and device electronics. In some embodiments, the cooling loop is configured as a thermal siphon that uses a boiling fluid to transport heat between the evaporator and the radiators. In some embodiments, the evaporator also functions as a device chassis, which reduces the overall part count. In some embodiments, the light source is a plurality of LEDs. LEDs have a well defined thermal performance and therefore operate properly within a defined temperature range. The cooling system is designed to maintain the LED temperatures within the defined temperature range. The one or more power supply units are arranged such that heat generated by the one or more power supply units does not negatively impact the thermal performance of the LED light source.
The evaporator 14 is a fluid-based heat exchanger that conceptually functions as a boiling unit. In some embodiments, the evaporator 14 includes a fluid reservoir that is filled, or partially filled, with a fluid or fluid mixture, herein referred to collectively as a fluid. The evaporator 14 is thermally coupled to the light source such that heat generated by the light source is transferred to the fluid within the evaporator 14. The heat causes fluid in the evaporator 14 to evaporate. The resulting vapor rises through the vertically ascending pipes 16, 26 to the radiators 18, 28. In some embodiments, each pipe 16, 26 includes a first portion that extends straight up from the evaporator 14 and a second portion that bends at an angle from completely vertical, but not horizontal, which is coupled to the radiator 18, 28. In some embodiments, the angle of the second portion is 45 degrees relative to vertical. The portion of pipes 16, 26 shown in
The radiator 18 is aligned at a decline, or downward angle relative to horizontal, such that one end is higher than the other end. The pipe 16 is coupled to a top portion of the radiator 18 and the return pipe 20 is coupled to a bottom portion of the radiator 18. In some embodiments, the pipe 16 is coupled to an end of the top portion of the radiator 18. In some embodiments, the return pipe 20 is coupled to an end of the bottom portion of the radiator 18. Vapor entering the radiator 18 from the pipe 16 condenses and the liquid flows downward through the radiator 18 to the return pipe 20. Due to the declining orientation of the radiator 18, liquid within the radiator is gravity fed toward the bottom end and to the return pipe 20. The return pipe 20 is aligned at a decline such that one end is higher than the other end such that liquid received from the radiator 18 is gravity fed to the evaporator 14.
The second cooling loop is configured similarly as the first cooling loop. The radiator 28 is aligned at a decline, or downward angle relative to horizontal, such that one end is higher than the other end. The pipe 26 is coupled to a top portion of the radiator 28 and the return pipe 30 is coupled to a bottom portion of the radiator 28. In some embodiments, the pipe 26 is coupled to an end of the top portion of the radiator 28. In some embodiments, the return pipe 30 is coupled to an end of the bottom portion of the radiator 28. Vapor entering the radiator 28 from the pipe 16 condenses and the liquid flows downward through the radiator 28 to the return pipe 30. Due to the declining orientation of the radiator 28, liquid within the radiator is gravity fed toward the bottom end and to the return pipe 30. The return pipe 30 is aligned at a decline such that one end is higher than the other end such that liquid received from the radiator 28 is gravity fed to the evaporator 14.
The cooling loops are described above has having separate pipes 16 and 26 that couple the evaporator to the radiators 18 and 28, respectively. Alternatively, the pipes 16 and 26 can include a common portion that splits for coupling to the radiators 18 and 28. For example, a single vertically ascending pipe can be coupled to the evaporator 14, and at a top portion of the pipe, the pipe branches, such as into two branches, each branch bends at an angle from completely vertical, but not horizontal. One or more branches are coupled to the radiator 18 and one or more branches are coupled to the radiator 28. Still alternatively, multiple separate pipes can be coupled between the evaporator 14 and a single radiator. For example, two or more pipes, each pipe similar to the pipe 16, can be coupled between the evaporator 14 and the radiator 18.
As shown in
In some embodiments, the fluid is a fluid mixture consisting of at least two different types of fluids that each evaporate at a different temperature. The thermal characteristics of the cooling system and fluid mixture are configured such that the heat supplied to the fluid within the evaporator is sufficient to evaporate one of the fluids, but insufficient to evaporate the second fluid. The evaporated fluid forms vapor bubbles within the remaining non-evaporated fluid mixture. In this manner, heat transferred to the fluid mixture results in a boiling fluid, a portion of which is a vapor and another portion of which is a liquid. The configuration of the fluid mixture and the vertically ascending pipes enables a pumping means whereby the boiling fluid, including the vapor and liquid forms of fluid mixture, rises from the evaporator 14, through the pipes 16 and 26, to the radiators 18 and 28. The vapor bubbles within the boiling fluid are used to siphon non-evaporated fluid up the pipes 16 and 26 and into the radiators 18 and 28. In this manner, a pumping means is integral to the cooling loop without including a discrete pumping component such as a powered pump. An example of such a pumping means is a bubble pump found in U.S. Patent Application Publication No. 2007/0273024, which is hereby incorporated in its entirety be reference. Although the boiling fluid includes a non-evaporated liquid component, this liquid component has been heated and as such the circulating liquid provides additional thermal transport from the evaporator to the radiator. In the case where the pipes 16 and 26 are finned pipes, heat from the rising boiling fluid can be shed during transport through the pipes 16 and 26.
Alternative configurations of the lighting assembly are also contemplated.
As shown in
The lighting assembly includes a mounting structure 110 coupled to the evaporator 114 and positioned in the pathway between the radiators 118 and 128. The mounting structure 110 includes handles 111 for carrying the lighting assembly. In this exemplary configuration, the lighting assembly includes four power supplies 106. The power supplies 106 can be mounted to the mounting structure 110, as shown, the evaporator 114, the vertically ascending pipes 116 and 126 or some combination thereof. An external mounting base 107 is coupled to the mounting structure 110 and/or to the evaporator 114. Bracing elements 113 provide additional support and couple the radiators 118 and 128 to the mounting structure 110, the external mounting base 107, the evaporator 114 or some combination thereof. The external mounting base 107 is used to mount the lighting assembly. In some embodiments, the external mounting base 107 is configured to receive a conduit, which in turn is mounted to an external support, such as a ceiling.
In the configuration shown in
As described above, the evaporator is configured to transfer heat from a light source coupled to the evaporator to fluid within the evaporator.
In some embodiments, the light source 36 is a plurality of LEDs mounted to a printed circuit board. Printed circuit boards are inherently flexible. Attaching such a flexible substrate to a rigid thermal exchange interface and achieving the requisite thermal interface between the two requires many fasteners, both along the perimeter and interior of the printed circuit board. The printed circuit board can be modified for enhanced rigidity. In some embodiments, the printed circuit board is bonded thermally and physically to a thicker, rigid substrate, such as a metal plate, to form a board assembly. The rigid substrate is made of a thermally conductive material, such as aluminum. As such, the board assembly provides structural rigidity and thermal conductance. Bonding the metal plate to the printed circuit board also provides improved thermal communication over the entire overlapping areas of the metal plate and printed circuit board. The board assembly is fastened to the thermal interface surface 32 of the evaporator 14 via the thermal interface material 34. The rigid board assembly can be attached to the thermal interface surface 32 using fewer fasteners than if the printed circuit board alone is attached to the thermal interface surface 32. For example, the board assembly can be attached to the thermal interface surface 32 using fasteners around the perimeter. No interior fasteners are needed in this case due to the rigidity of the board assembly. Due to the rigid structure, proper thermal communication is established across the entire board assembly and thermal interface surface even though fasteners are only sparsely applied, such as about the perimeter. Without the board assembly, mounting a printed circuit board may require a screw positioned every inch or so in a grid pattern to supply enough normal force to the printed circuit board to provide proper thermal communication with the thermal interface surface 32. In contrast, the rigid substrate of the board assembly provides continuous contact of the substrate in response to a reduced number of normal force points, such as along the perimeter.
The use of fewer fasteners provides a number of advantages including easier and faster assembly and lower costs. Additionally, fewer fasteners speeds the process of replacing a light source in an already installed lighting assembly. The board assembly is mounted to the evaporator 14 using any conventional mounting means including, but not limited to, screws, clamps, and/or brackets. To provide additional speed and ease for replacing an installed light source, the board assembly can be mounted using quick release latches or other mounting mechanisms that allow for quick and easy removal and replacement. In this manner, the rigid board assembly enables an installed lighting assembly to be “relampable” where the light source can be simply replaced.
As shown in
In some embodiments, the upper spherical casing 42 and the lower base 44 are designed with an interface that allows them to be made with different processes to optimize costs. The separation of the upper spherical casing and the lower base allows the upper portion to be cast, for example, while the lower base is machined, for example, to achieve higher precise and more optimal heat transfer.
In some embodiments, the thermal exchanging surface of the evaporator is a non-planar surface. In this alternative configuration, a contour of the thermal exchanging surface is configured to match that of the corresponding thermal exchange surface of the light source. In some embodiments, the light source is configured with a plurality of planar surfaces angled relative to each other. In an exemplary configuration, the light source is a multi-facet LED light source where each facet is a planar surface having a plurality of LEDs. The facets are angled so as to provide a desired lighting pattern and backfilling. Configuring the light source as a multi-facet LED light source reduces shadowing and provides light directly to an external illumination surface without having to use additional secondary optical elements such as a reflector and/or lenses.
In contrast to the planar light source 36 in
In some embodiments, the second substrate 64 is rotatably coupled to the first substrate 62 so as to be able to change an angle between the first planar surface 68 and the second planar surface 70, and the third substrate 66 is rotatably coupled to the first substrate 62 so as to as to be able to change an angle between the first planar surface 68 and the third planar surface 72. These angles are set or changed to achieve a desired lighting pattern generated by the light source 60. In the exemplary configuration shown in
As shown in
As shown in
The LEDs can be positioned on a planar surface in any desired pattern. The spacing between LEDs is application specific, which when combined with the angles of the light emitting surfaces, is designed to achieve a specific light intensity per unit area. The size of the LEDs impacts this determination as smaller LEDs typically generate less illumination than larger LEDs.
In an exemplary application, the lighting assembly is designed for high bay lighting, such as 40-50 feet high ceilings. In such an application, the lighting assembly generates 100-400 kW. In some applications, the lighting assembly generates more than 400 kW. In general, the lighting assembly is useful for those applications requiring lighting solutions with higher wattages than those found in typical office environments having 8-10 feet high ceilings.
The present application has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the multi-facet LED device. Many of the components shown and described in the various figures can be interchanged to achieve the results necessary, and this description should be read to encompass such interchange as well. As such, references herein to specific embodiments and details thereof are not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications can be made to the embodiments chosen for illustration without departing from the spirit and scope of the application.
Claims
1. A lighting assembly comprising:
- a. a plurality of light emitting diodes;
- b. a first substrate wherein the plurality of light emitting diodes are electrically and mechanically coupled to the first substrate; and
- c. a second substrate thermally and mechanically coupled to the first substrate, wherein the second substrate is rigid and comprises thermally conductive material.
2. The lighting assembly of claim 1 wherein the first substrate comprises a printed circuit board.
3. The lighting assembly of claim 1 wherein the second substrate comprises a metal plate.
4. The lighting assembly of claim 3 wherein the metal plate comprises aluminum.
5. The lighting assembly of claim 1 wherein the second substrate and the first substrate are bonded together.
6. A lighting assembly comprising:
- a. a plurality of light emitting diodes;
- b. a first substrate wherein the plurality of light emitting diodes are electrically and mechanically coupled to the first substrate;
- c. a second substrate thermally and mechanically coupled to the first substrate, wherein the second substrate is rigid and comprises a thermally conductive material;
- d. a mounting structure wherein the second substrate is thermally and mechanically coupled to the mounting structure; and
- e. a plurality of fastening devices configured to mechanically couple the second substrate to the mounting structure.
7. The lighting assembly of claim 6 wherein the mounting structure comprises a heat exchanging device.
8. The lighting assembly of claim 6 further comprising a thermal interface material between the second substrate and the mounting structure.
9. The lighting assembly of claim 6 wherein the thermal interface material comprises a thermally conductive pad, a thermally conductive epoxy, a thermally conductive grease, or a thermally conductive adhesive.
10. The lighting assembly of claim 6 wherein the plurality of fastening devices comprises a plurality of screws, a plurality of clamps, a plurality of brackets, or a plurality of quick release latches.
11. The lighting assembly of claim 6 wherein the first substrate comprises a printed circuit board.
12. The lighting assembly of claim 6 wherein the second substrate comprises a metal plate.
13. The lighting assembly of claim 12 wherein the metal plate comprises aluminum.
14. The lighting assembly of claim 6 wherein the second substrate and the first substrate are bonded together.
Type: Application
Filed: Jun 18, 2013
Publication Date: Jan 2, 2014
Inventors: Jordon Musser (Coppell, TX), Chris Stratas (Burlingame, CA)
Application Number: 13/921,044
International Classification: H01L 33/64 (20060101);