Multi-sided thermal management device for electronic devices

Abstract

An LED device includes a multi-sided heat diffuser element having longitudinal multi-sided walls that at least partially enclose an interior space, and having a plurality of LEDs mounted to the outer surface of the heat diffuser element, and a flow space for a cooling medium in the interior space. The tubular heat diffuser element has at least one layer of heat-conductive metal that can be bent from a straight shape to a multi-sided shape. The multi-sided shape can be tubular with smoothly curved or multi-sided polygonal walls. The walls of the LED device can include a two-phase cooling element such as a vapor chamber to maintain the LED at a constant temperature, and can include a temperature control fan unit to control the LED temperature, and also control the wavelength and frequency of light emitted by the LED. A method for manufacturing an LED device is also disclosed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 872,058, filed on July 9, 2019, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to thermal management of electronic devices such as electronic lighting devices, and more particularly to multi-sided thermal management devices for electronic devices, and to electronic devices incorporating multi-sided thermal management devices. Background Art

[0004] Electronic devices contain heat-generating electronic components such as light emitting diodes (LEDs) and computer chips mounted on circuit boards. Examples of such devices are electronic lighting devices such as lamps or light bulbs, where light is generated by LEDs rather than incandescent elements. The electronic components of such electronic devices generate heat and must be cooled to avoid performance degradation and damage due to overheating. For example, LEDs should be maintained at a temperature below about 105°C.

[0005] While conventional ambient air cooling, by itself or in combination with cooling fins, heat sinks, or heat pipes, is sufficient to cool relatively low power electronic lighting devices, such conventional cooling techniques may be insufficient for higher power electronic lighting devices, such as those having a power of about 100 W to about 1,000 W or more. Furthermore, it may be challenging to provide sufficient surface area for cooling in an electronic lighting device that is intended to replace a conventional incandescent or halide lamp.

[0006] There remains a need for compact and effective thermal management devices for electronic lighting devices, particularly for relatively high power lighting devices intended to replace conventional incandescent or halide lamps. Summary of the invention

[0007] According to one aspect of the present disclosure, there is provided a thermal management device for electronic components, comprising: (a) a multi-sided heat spreader element, the heat spreader element defining a longitudinal axis and including a longitudinally extending multi-sided wall and an interior space at least partially enclosed within the multi-sided wall, the multi-sided wall having an inner surface, an outer surface, and a first end and a second end spaced apart longitudinally; (b) a plurality of electronic components mounted to the outer surface of the wall of the heat spreader element; and (c) a flow space for a cooling medium, the flow space being disposed in the interior space of the heat spreader element;

[0008] According to one aspect, a tubular heat spreader element includes at least one layer of thermally conductive metal that is bendable from a straight shape to a multi-sided shape.

[0009] According to one aspect, the thermal management device further includes a plurality of upstanding fins disposed along and in thermal contact with at least one of the inner and outer surfaces of the plurality of side walls of the heat spreader element.

[0010] According to one aspect, at least some of the upstanding fins have free edges extending substantially transversely to the longitudinal axis.

[0011] According to one aspect, the multi-side walls of the heat spreader element include at least one two-phase cooling element, wherein each two-phase cooling element is a vapor chamber or a heat pipe.

[0012] According to one aspect, each of the at least one two-phase cooling elements is elongated along a longitudinal axis; wherein each of the at least one two-phase cooling elements includes an evaporation region and a condensation region; and wherein each of the plurality of electronic components is located on top of and in thermal contact with the evaporation region of one of the at least one two-phase cooling elements.

[0013] According to one aspect, the thermal management device further comprises a plurality of upright fins, each of the plurality of upright fins being disposed on and in thermal contact with an inner surface or an outer surface of the plurality of side walls, and wherein each of the upright fins is located on top of and in thermal contact with a condensation zone of one of the two-phase cooling elements.

[0014] According to one aspect, the thermal management device further includes one or more holes passing through the multi-side wall to allow a cooling medium to flow between the inner and outer surfaces of the multi-side wall.

[0015] According to one aspect, at least one bendable layer of the multi-sided wall is smoothly bent to provide the tubular wall of the heat sink with a smooth rounded shape when viewed in transverse cross-section.

[0016] According to one aspect, at least one bendable layer of the multi-sided wall bends along a plurality of bend lines extending between a first end and a second end of the multi-sided wall such that the multi-sided wall of the heat spreader element comprises a plurality of faces when viewed in transverse cross-section.

[0017] According to one aspect, the thermal management device further comprises one or more holes passing through the multi-side wall to allow a cooling medium to flow between the inner surface and the outer surface of the multi-side wall; wherein the holes are arranged along the bend line.

[0018] According to one aspect, the thermal management device further comprises a plurality of upstanding fins disposed along at least one of an inner surface and an outer surface of the multi-side wall of the heat spreader element and in thermal contact therewith; wherein the plurality of upstanding fins are arranged into a plurality of discrete groups, each discrete group of upstanding fins being disposed on one face of the multi-side wall; and wherein the discrete groups of upstanding fins are spaced apart from one another by bend lines and holes between faces of the multi-side wall.

[0019] According to one aspect, the bend lines between the faces extend substantially longitudinally, and at least one of the bend lines is predefined by perforating, scoring, or slotting at least one bendable layer of the multi-sidewall along the bend line.

[0020] According to one aspect, the thermal management device also includes a first flow space, which is used for cooling medium, and the first flow space is arranged along the inner surface of the heat diffuser element, and the first flow space has an inlet and an outlet spaced apart along the longitudinal axis; and a turbulence enhancement insert, which is arranged in the first flow space; wherein the turbulence enhancement insert includes a plurality of corrugations, and the plurality of corrugations are arranged to have longitudinally oriented openings passing through the corrugations.

[0021] According to one aspect, the multi-side wall of the heat diffuser element is tubular, and the thermal management device also includes a tubular inner sleeve radially spaced inward from the tubular wall of the heat diffuser element, wherein the tubular inner sleeve includes a longitudinal wall portion having a hollow interior, the hollow interior defines a second flow space for a cooling medium, and wherein the first flow space is defined between the longitudinal wall portion of the tubular inner shell and the tubular wall of the heat diffuser element; wherein the corrugations of the turbulence enhancement insert each have a top surface in thermal contact with the tubular wall of the heat diffuser element, a bottom surface in thermal contact with the longitudinal wall portion of the tubular inner shell, and radially oriented side walls extending between the top surface and the bottom surface.

[0022] According to one aspect, the thermal management device further comprises one or more heat generating components, which are located inside the longitudinal wall portion of the tubular inner shell; wherein the tubular inner shell further comprises a transverse wall, which extends across the interior of the longitudinal wall portion; and wherein the transverse wall is provided with one or more holes to allow a cooling medium to flow through the second flow space.

[0023] According to one aspect, the plurality of electronic components comprises a plurality of light emitting diodes (LEDs); wherein the thermal management device further comprises a fan unit positioned proximate a first end or a second end of the plurality of side walls of a heat diffuser element, the fan unit being adapted to circulate a cooling medium through an interior space of the heat diffuser element; wherein the fan unit comprises a temperature responsive proportional speed control to maintain the light emitting diodes at a specific temperature, thereby maintaining a specific color or light output.

[0024] According to one aspect, the plurality of electronic components include a plurality of light emitting diodes (LEDs), and wherein the thermal management device further includes a transparent or translucent lens disposed over the outer surface of the plurality of side walls of the heat spreader element and over the LEDs.

[0025] According to one aspect of the present disclosure, there is provided a method of manufacturing a thermal management device as herein described. The method comprises: providing a flat metal substrate, the metal substrate comprising at least one bendable layer of tubular wall; forming a plurality of bend lines on at least one of an inner surface and an outer surface of the flat metal substrate, wherein the plurality of bend lines are formed by scoring, punching or slotting the flat metal substrate; and bending the flat metal substrate along the bend lines and forming a multi-sided heat spreader element, wherein the multi-sided heat spreader element comprises a plurality of faces, each face being substantially flat and defined between two bend lines.

[0026] According to one aspect, the method further comprises mounting electronic components on the outer surface of the flat metal substrate before the step of bending the flat metal substrate.

[0027] According to one aspect of the present disclosure, there is provided a light emitting diode device including a plurality of light emitting diodes and a thermal management device for controlling the temperature and the wavelength of radiation emitted by the plurality of light emitting diodes. The thermal management device includes: (a) a multi-sided heat diffuser element, the heat diffuser element defining a longitudinal axis and including a multi-sided wall extending longitudinally and an interior space at least partially enclosed within the multi-sided wall, the multi-sided wall having an inner surface, an outer surface supporting a light emitting diode, and a first end and a second end spaced apart longitudinally; (b) at least one two-phase cooling element, wherein each two-phase cooling element is a vapor chamber or a heat pipe; wherein each of the at least one two-phase cooling element is elongated along the longitudinal axis; wherein each of the at least one two-phase cooling element includes an evaporation region in thermal contact with one or more light emitting diodes, and a condensation region spaced apart from the light emitting diodes along the longitudinal axis; (c) a flow space for a cooling medium, the flow space being disposed in the interior space of the heat diffuser element; and (d) a temperature-controlled fan unit, the temperature-controlled fan unit being adapted to circulate a cooling medium through the interior space of the heat diffuser element, wherein the fan is operable to control a temperature and a wavelength of radiation emitted by the light emitting diode based on a temperature of the heat diffuser element, the at least one two-phase cooling element, and at least one of the light emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Exemplary embodiments of the present disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0029] Figure 1 is a perspective view of a thermal management device according to a first embodiment;

[0030] Figure 2 yes Figure 1 A partially exploded perspective view of a thermal management device;

[0031] Figure 3 yes Figure 1 A cross-sectional view of a heat diffuser element and a turbulence enhancement insert of a thermal management device;

[0032] Figure 4 yes Figure 1 A cross-sectional view of an inner sleeve of a thermal management device;

[0033] Figure 5A yes Figure 1 An exploded view of a heat spreader element and a two-phase cooling element of a thermal management device;

[0034] Figure 5B yes Figure 1 An enlarged view of two sides of the thermal management device;

[0035] Figure 5C yes Figure 1 An exploded view of one of the two-phase cooling elements of a thermal management device of FIG. 1 and illustrating a variation in the configuration of the two-phase cooling element;

[0036] Figure 6 It passes through Figure 1 A middle longitudinal cross-sectional view of a thermal management device;

[0037] Figure 7 It passes through Figure 1 A transverse cross-sectional view of a thermal management device;

[0038] Figure 8 yes Figure 7 A partial enlarged view of the cross section;

[0039] Fig. 9 is a perspective view of a thermal management device according to a second embodiment;

[0040] Fig.10 is a perspective view of a heat spreader element of a second embodiment shown in a flat form;

[0041] Fig.11 is a perspective view of another heat spreader element shown in a flat form;

[0042] Fig.12 is a perspective view of a thermal management device according to a third embodiment;

[0043] Fig.13 is a perspective view of a thermal management device according to a fourth embodiment;

[0044] Fig.14 yes Fig.13 A partial end view of a thermal management device;

[0045] Fig.15 yes Fig.13 A partial end view of another thermal management device;

[0046] Fig.16 is a perspective view of a heat spreader element showing another type of connector and the mounting of LEDs on an outer surface thereof;

[0047] Fig.17 is a perspective view of a heat spreader element of a thermal management device according to a fifth embodiment shown in a flat form; and

[0048] Fig.18 yes Fig.17 A partially cutaway perspective end view of a thermal management device. DETAILED DESCRIPTION

[0049] Reference now Figures 1 to 8 A heat management device 10 according to a first embodiment is described below.

[0050] The thermal management device 10 includes a heat spreader element 12 having a multi-sided non-linear configuration and having a Figure 3 1 is shown as being separated from the other components of the heat diffuser element 12. The heat diffuser element 12 includes a plurality of side walls 14 extending along a longitudinal axis L ( Figure 1 ) and has an inner surface 16 and an outer surface 18. The heat diffuser element 12 has first and second ends 20, 22 spaced apart in a longitudinal direction, and in the present embodiment, the first and second ends 20, 22 are open. Due to its multi-sided configuration, the wall 14 of the heat diffuser element 12 can define an open enclosure at least partially surrounding the interior space 24. The multi-sided non-linear heat diffuser element 12 shown in the figures has the wall 14 having a tubular shape, but this is not required. The multi-sided non-linear shape of the wall 14 can be partially open along its sides, such as a C-shape, a U-shape, etc., regardless of whether the wall 14 is smooth or multi-sided, as further described below.

[0051] When viewed from the end or transverse section, the wall 14 of the heat spreader element 12 has a plurality of facets 26, each of which may be substantially flat. A total of ten facets 26 make up the wall 14 of the heat spreader element 12, and these facets 26 include rectangles of substantially the same size, so that when viewed in a transverse plane, the wall 14 may define a regular decagon.

[0052] Although the wall 14 has ten identical faces 26, this is not necessary. The number and size of the faces 26 will depend on many factors, as discussed further below. In the case where the wall 14 is multi-faceted, it will include at least three faces, where the upper limit of the number of faces is not particularly limited. In the present embodiment, the longitudinal bend 28 is defined by the bend line between the faces 26, along which the wall 14 bends. The longitudinal bend 28 is straight and extends between the first end 20 and the second end 22, parallel to the longitudinal axis, so that the wall 14 has a constant diameter. However, it is understood that the wall 14 does not necessarily have a constant diameter, and can, for example, be tapered so that the sides of the face 26 and the bend 28 are angled relative to the longitudinal axis. For example, with a tapered wall 14, the heat diffuser element 12 can have a conical or truncated cone shape, wherein the conical or truncated cone wall 14 optionally includes a plurality of flat tapered faces 26.

[0053] In other embodiments, the wall 14 may be smoothly rounded such that when viewed in a transverse plane, the wall 14 defines a circular, oval, or other rounded shape.

[0054] In this embodiment, the wall 14 may include at least one layer of thermally conductive metal that may be bent or folded from a planar shape into the shape of the wall 14 by bending along bends 28, and the shape of the wall 14 may be predefined in the sheet material by perforating or scoring the sheet material along bend lines 28, as further described below. Thus, the wall 14 includes at least one bendable layer to allow it to be rolled and / or bent into a tubular shape.

[0055] A plurality of electronic components 30 are disposed proximate to the outer surface of the wall 14 of the heat spreader element 12. In the present embodiment, each electronic component 30 comprises a light emitting diode (LED). The LED 30 is in thermal contact with the outer surface of the wall 14 and may be electrically conductive, for example, via a thermally conductive dielectric layer (e.g., a thermal interface material (TIM) 32). Fig. 9 , 16 ) and circuit board 34( Fig. 9 , 16 ) is mounted directly to the wall 14, and each circuit board 34 carries one or more LEDs 30. The LEDs 30 are spaced apart from one another on the outer surface 18 of the wall 14, so that the thermal management device 10 forms part of an LED lamp. The number of LEDs 30 is selected so that the LED lamp will have a specific wattage and emit a predetermined amount of light. For example, the thermal management device 10 described herein may have a wattage ranging from less than 100 watts to more than 1000 watts. It will be appreciated that not every face 26 is required to carry one or more LEDs 30.

[0056] For example, the thermal management device 10 according to the present embodiment can be configured for use with a 240 watt LED lamp, with each face 26 having a sufficient number of LEDs 30 to provide a wattage of 24 watts. The LED lamp incorporating the thermal management device 10 can have a diameter of approximately 6 cm and a length of approximately 10 cm, wherein the LEDs 30 and the outer surface 18 of the heat diffuser element 12 are covered by a transparent or translucent lens.

[0057] The LEDs 30 generate a significant amount of heat during use, and cooling is required to maintain the LEDs 30 at a temperature at which they will operate efficiently and with minimal degradation. For example, the thermal management device 10 can be configured to maintain the LEDs 30 at a temperature of about 105° C. or less. In the present embodiment, cooling is provided by circulating a cooling medium along the inner surface 16 of the wall 14 and optionally along the outer surface 18 of the wall 14, wherein the cooling medium flows in a direction at least generally parallel to the longitudinal axis L. The circulating cooling medium is in contact with the inner and / or outer surfaces 16, 18 of the wall 14, and may also be in direct contact with the LEDs 30, absorbing heat generated by the LEDs 30.

[0058] The thermal management device 10 also includes a flow space 36 for circulating a cooling medium along the inner surface 16 of the wall 14 of the heat diffuser element 12. The flow space 36 may have an inlet 38 and an outlet 40 spaced apart along the longitudinal axis L. In the present embodiment, the inlet 38 and the outlet 40 have an annular or polygonal shape and are proximate to the first end 20 and the second end 22 of the heat diffuser element 12.

[0059] The flow space 36 of the thermal management device 10 is defined between an outer wall 42 and an inner wall 44 (both of which have a tubular configuration), and is also referred to herein as a "first flow space". In the present embodiment, the outer wall 42 of the flow space 36 corresponds to the wall 14 of the heat diffuser element 12, and reference to the outer wall 42 in the description of the present embodiment is equivalent to reference to the wall 14 of the heat diffuser element 12, and vice versa. The inner wall 44 of the flow space 36 is radially inwardly spaced from the outer wall 42.

[0060] A plurality of upright heat sink fins, such as corrugated fins or turbulators, are disposed within the flow space 36 of the thermal management device 10 in the form of turbulence enhancement inserts 46. As further described below, the upright heat sink fins may be disposed on the inner and / or outer surfaces 20, 22 of the wall 14 of the heat diffuser element 12. The turbulence enhancement inserts 46 and upright heat sink fins in general may increase the area of ​​the heat transfer surface of the heat diffuser element 12 and may improve heat transfer from the thermal management device 10 to the cooling medium. The turbulence enhancement inserts 46 provide turbulence in the flow of the cooling medium, thereby enhancing heat transfer from the LEDs 30 to the cooling medium through the wall 14 (outer wall 42) of the heat diffuser element 12. The turbulence enhancement inserts 46 may enhance the stiffness of the wall 14 of the heat diffuser element 12 and the thermal management device 10. In addition, the turbulence enhancement inserts 46 may separate the flow space 36 into a plurality of longitudinally extending fluid flow paths.

[0061] As used herein, the terms "fin" and "turbulator" refer to a corrugated turbulence enhancement insert 46 having a plurality of ridges or peaks 48 connected by sidewalls 50, and the ridges 48 are rounded or flat. As defined herein, a "fin" has continuous ridges, while a "turbulator" has corrugations that are interrupted along its length to provide a tortuous flow path. Turbulators are sometimes referred to as offset or lanced strip fins, and examples of such turbulators are described in U.S. Patent No. Re. 35,890 (So et al.) and U.S. Patent No. 6,273,183 (So et al.). The patents of So and So et al. are incorporated herein by reference in their entirety.

[0062] In the thermal management device 10, the turbulence enhancement insert 46 has flat ridges 48 and radially extending (vertical) sidewalls 50, and includes offset strip-shaped fins in which the corrugations are interrupted along their (longitudinal) length, and the offset of adjacent portions of the corrugations is about half the corrugation width. The insert 46 is oriented inside the space between the outer wall 42 and the inner wall 44 so that its ridges 48 are arranged parallel to the flow direction of the cooling medium so that the openings through the corrugations are longitudinally oriented. Each ridge 48 is in thermal contact with the inner surface of the outer wall or inner wall 42, 44. The ridges 48 of the turbulence enhancement insert 46 can be metallurgically bonded to the inner surfaces of the outer wall 42 and the inner wall 44, such as by brazing or soldering. Although metallurgical bonding is not required, it provides a good heat transfer path between the wall 14 of the heat diffuser element 12 and the insert 46.

[0063] The turbulence enhancement insert 46 itself may include a multi-faceted structure formed from a single sheet of metal. For example, the insert 46 may include a plurality of corrugated portions 52, each corresponding to one of the faces 26 of the heat diffuser element 12, and having non-corrugated bends 54 disposed between adjacent corrugated portions 52. The insert 46 is initially in the form of a flat sheet having corrugations with ridges 48 and sidewalls 50, and is then bent along each bend 54 to form the multi-faceted structure shown in the figure. Although not required, the bends 54 are provided with predefined longitudinal bend lines, such as by perforating or scoring the sheet, to ensure that the bends in the insert 46 are radially aligned with the bends 28 in the wall 14 of the heat diffuser element 12.

[0064] The turbulence enhancement insert 46 has a length along the longitudinal axis L that is substantially the same as the length of the wall 14 of the heat diffuser element 12, such that turbulence of the cooling medium is provided along substantially the entire length of the heat diffuser element 12. Thus, the turbulence enhancement insert 46 has a first end 56 proximate the first end 20 of the heat diffuser element 12 and a second end 58 proximate the second end 22 of the heat diffuser element 12. In the present embodiment, the first and second ends 56, 58 of the turbulence enhancement insert 46 are substantially longitudinally aligned with the first and second ends 20, 22 of the heat diffuser element 12.

[0065] In this embodiment, the inner wall 44 of the flow space 36 includes a tubular inner sleeve 60 having a hollow interior 62 and a shape corresponding to the shape of the wall 14 of the heat diffuser element 12. In this embodiment, the inner sleeve 60 has a longitudinal wall portion that includes a plurality of faces 64 separated by a plurality of bends 66. The shape and number of the faces 64 correspond to the shape and number of the heat diffuser element 12, wherein the bends 66 are radially aligned with the bends 54 of the turbulence enhancement insert 46 and the bends 28 of the heat diffuser element 12. Although not required, the inner sleeve 60 is shown in the drawings (e.g., Figure 8 ) is shown as having a thickness greater than the thickness of the wall 14 and the turbulence enhancement insert 46 in order to provide structural support for the thermal management device 10.

[0066] The longitudinal wall portion of the inner sleeve 60 has a first end 68 and a second end 70, the first end 68 of the inner sleeve 60 being proximate to the first ends 20, 56 of the heat diffuser element 12 and the turbulence enhancement insert 46, and the second end 70 of the inner sleeve 60 being proximate to the second ends 22, 58 of the heat diffuser element 12 and the turbulence enhancement insert 46. In the present embodiment, the second end 70 of the inner sleeve 60 is substantially longitudinally aligned with the second ends 22, 58 of the heat diffuser element 12 and the turbulence enhancement insert 46, and the second end 70 of the inner sleeve 60 may be configured to have a radially outwardly extending lip 72. As shown in the figure, the lip 72 may be multi-sided.

[0067] The outlet 40 of the flow space 36 is defined as a multi-faceted annular space at the wall 14, the turbulence enhancement insert 46, and the second end 22, 58, 70 of the inner sleeve 60. An outwardly extending lip 72 is provided to define an area of ​​the annular opening that constitutes the outlet 40 of the flow space 36. The lip 72 also helps to align the inner sleeve 60 relative to the turbulence enhancement insert 46.

[0068] For reasons to be explained below, the inner sleeve 60 is slightly shorter than the wall 14 of the heat diffuser element 12 such that the inlet 38 of the flow space 36 is defined as a multi-sided annular space between the first end 68 of the tubular inner sleeve 60 and the inner surface 16 of the wall 14 of the heat diffuser element 12, and the first end 20 of the heat diffuser element 12 extends longitudinally beyond the inlet 38. In the present embodiment, the first end 56 of the turbulence enhancement insert 46 extends to the first end 20 of the heat diffuser element 12, however, it will be appreciated that the first end 56 of the turbulence enhancement insert 46 may alternatively terminate at or near the first end 68 of the inner sleeve 60.

[0069] from Figure 4 It can be seen that the inner sleeve 60 includes a transverse wall 74 extending across the hollow interior 62 of the longitudinal wall portion of the inner sleeve 60. The transverse wall 74 can be located anywhere between the first end 68 and the second end 70 of the inner sleeve 60, however, in order to guide the cooling medium into the inlet 38 of the flow space 36, the transverse wall 74 is located at the first end 68 of the inner sleeve 60.

[0070] In the present embodiment, the transverse wall 74 is not perforated so that all cooling medium will enter the inlet 38 of the flow space 36, and no cooling medium will flow through the hollow interior 62 of the inner sleeve 60. However, in some embodiments, one or more heat generating components may be located inside the hollow interior 62. For example, where the thermal management device 10 comprises a portion of an LED lamp, the electronic components 76 (in the embodiment of the embodiment of the present invention) for controlling the operation of the LED 30 may be located inside the hollow interior 62. Figure 6The electronic components 76 (shown in dashed lines in FIG. 1 ) may be located inside the hollow interior 62. In conventional LED lamps, these electronic components 76 are located in the base of the lamp and may increase the length dimension of the lamp. Therefore, incorporating the electronic components 76 into the hollow interior 62 may save space.

[0071] In the case where these heat generating components are incorporated into the hollow interior 62 of the inner sleeve 60, the transverse wall 74 may be provided with one or more perforations 78 (eg, Figure 6 ), to allow a cooling medium to flow through the hollow interior 62 (also referred to herein as a “second flow space”) and cool the electronic components 76 .

[0072] Although the transverse wall 74 is shown as being flat, this is not required. For example, the wall 74 may have a rounded or conical shape that bulges outwardly in order to enhance the flow of the cooling medium into the inlet 38 of the flow space 36.

[0073] In the present embodiment, the cooling medium is gaseous and may include ambient air. Therefore, the thermal management device 10 includes a fan unit 80 positioned near the inlet or outlet 38, 40 of the flow space 36 to flow the cooling medium through the flow space 36 at a flow rate sufficient to maintain the LEDs 30 at a desired temperature.

[0074] The fan unit 80 of the thermal management device 10 is positioned near the first end 38 of the flow space 36 and blows the gaseous cooling medium into the first end 38 of the flow space 36. The fan unit 80 includes a fan blade 82 driven by a motor 84, wherein the fan blade 82 and the motor 84 may be mounted in a housing 86. The housing 86 includes a flat mounting flange 88 extending around the periphery of the fan unit 80. The housing 86 and the blades 82 of the fan unit 80 may be constructed of plastic.

[0075] The first end 20 of the heat diffuser element 12 may be provided with a radially outwardly extending flat mounting flange 90 to which the mounting flange 88 of the fan unit 80 may be secured. The mounting flanges 88, 90 may be provided with aligned openings 92, 94 to receive mechanical fasteners such as bolts (not shown). The mounting flanges 88, 90 may also be used to secure the thermal management device to the base of the lamp (not shown).

[0076] As can be seen, the fan blades 82 are longitudinally spaced from the inlet 38 of the flow space 36 such that the fan blades 82 are adapted to direct the flow of the cooling medium longitudinally toward the inlet 38. The transverse wall 74 of the inner sleeve 60 directs the flow of the cooling medium radially outward into the inlet 38 of the flow space 36. As can be seen, the longitudinal gap between the first end 68 of the inner sleeve 60 and the first end 20 of the heat diffuser element 12 can provide a radially inward space 96 through which the cooling medium enters the flow space 36 of the thermal management device 10.

[0077] Although the thermal management device 10 includes a fan unit 80, it will be appreciated that the fan unit 80 may not be required in all embodiments. For example, in some embodiments, the number of LEDs 30 may be such that natural convection of ambient air through the device 10 is sufficient to maintain the LEDs at an acceptable temperature. However, increasing the density and / or wattage of the LEDs 30 will increase the heat generated, and as the wattage increases, forced air from the fan unit 80 may be required. It will also be appreciated that the fan unit 80 may be controlled so that it is activated only when the temperature of the LEDs rises above a threshold level, or that the fan unit 80 may have a proportional speed control to maintain the LEDs 30 at a specific temperature in order to maintain a specific color (i.e., wavelength and / or frequency) or light output.

[0078] As described above, the plurality of electronic components 30 are disposed proximate to the outer surface of the wall 14 of the heat spreader element 12, and may include a plurality of LEDs in thermal contact with the outer surface 18 of the wall 14. The heat generated by the LEDs 30 is conducted to the wall 14 of the heat spreader element 12 and spreads across the entire area of ​​the wall 14. The heat is then transferred from the wall 14 to the turbulence enhancement insert 46 and to the cooling medium circulating through the flow space 36.

[0079] In some embodiments, the wall 14 of the heat diffuser element 12 includes a single flexible layer of thermally conductive metal. Examples of such embodiments will be further described below. In the present embodiment, the wall 14 of the heat diffuser element 12 also includes one or more two-phase cooling elements 98, each of which includes a vapor chamber or a heat pipe. Each two-phase cooling element 98 can have a construction as disclosed in commonly assigned U.S. Patent Application No. 16 / 047,484, which was filed on July 27, 2018, published as US 2019 / 0033006A1 on January 31, 2019, and is entitled "ULTRA THIN HEAT EXCHANGERS FOR THERMAL MANAGEMENT", which is incorporated herein by reference in its entirety. In this regard, each two-phase cooling element 98 is typically flat and planar and has a thickness in the range of approximately 200-2,000 microns. The single flexible layer of thermally conductive material may include a clad metal sheet such as those disclosed in publication number US 2019 / 0033006A1.

[0080] Where the wall 14 of the heat spreader element 12 includes a plurality of faces 26, each of the two-phase cooling elements 98 may be defined along one of the plurality of faces 26 and may correspond in shape to that face 26. To provide efficient cooling, the area of ​​each two-phase cooling element 98 is maximized so as to cover as much area as possible of each face 26. For these reasons, and also to provide a flat substrate for mounting LEDs, the two-phase cooling elements 98 are thin and flat and have substantially the same shape and area as the face 26. Thus, in this embodiment, the two-phase cooling elements 98 are relatively thin and elongated along the longitudinal axis.

[0081] As in Figure 5A , 5B As best seen in FIGS. 5C and 5C , the wall 14 of the heat spreader element 12 may have a two-layer or three-layer structure, depending on whether the two-phase cooling element 98 is formed integrally with the wall 14 or separately. In the two-layer structure, the wall 14 includes a first sheet-like element 100 that defines a flexible layer of thermally conductive metal along which the inner surface 16 of the wall 14 can be defined. The first sheet-like element 100 defines all of the faces 26 of the wall 14 and further defines bends 28 between the faces 26.

[0082] The wall 14 of the heat diffuser element 12 also includes a plurality of second sheet elements 102, each of which comprises a sheet of material formed by stamping or the like. Each second sheet element 102 has a shape and size substantially corresponding to the shape and size of one of the plurality of faces 26, having a flat flange 104 along its peripheral edge, along which the second sheet element 102 is sealingly joined to the first sheet element 100, such as by brazing or laser welding. Each second sheet element 102 includes a flat raised middle portion 106 located inside the flange 104, and a cavity 108 (at Figure 8 The cavity 108 is defined in the space between the raised middle portion 106 of each second sheet element 102 and the first sheet element 100. Each cavity 108 is thin and flat and has an area that substantially corresponds to the area of ​​one of the plurality of faces 26 minus the area of ​​the flange 104.

[0083] In the present embodiment, the first sheet element 100 constitutes an integral multi-faceted structure in which the bend 28 of the wall 14 is disposed. However, this is not required. For example, in other embodiments, between adjacent flanges 104, the second sheet element 102 may be integrated into a single multi-faceted structure in which the bend 28 of the wall 14 is disposed. In such alternative embodiments, the first sheet element 100 may have the form shown in the accompanying drawings, being an integral multi-faceted structure, or the first sheet element 100 may include a plurality of individual first sheet elements 100, each corresponding in size and shape to one of the faces 26 of the wall 14. As another alternative, the second sheet element 102 may be located on the inner surface of the multi-faceted first sheet element 100, such that the second sheet element 102 defines the inner surface 16 of the wall 14, and the first sheet element defines the outer surface 18 of the wall 14.

[0084] according to Figure 5C , each of the two-phase cooling elements 98 is defined by a pair of opposing inner and outer sheet elements 100, 102 that enclose a chamber 108. Each sheet element 100, 102 corresponds in size and shape to one of the multiple faces 26 of the wall 14, and the flexible layer of the wall 14 is defined as a separate multi-faceted structure 100'. The separately formed two-phase cooling element 98 can be attached to the wall 14 by a metallurgical bond such as brazing, welding, or soldering.

[0085] As disclosed in the above-mentioned publication number US 2019 / 0033006A1, the first and second sheet elements 100, 102 can be made of stainless steel and can be coated on one or both sides with a low melting point metal that is inert to the working fluid, such as copper or nickel. The first and second sheet elements 100, 102 can be metallurgically bonded together by welding, including laser welding as disclosed in the publication number US 2019 / 0033006A1.

[0086] In certain embodiments, the outer surfaces of the first and second sheet-like elements 100, 102 (the surfaces facing away from the chamber 108) may include a cladding that is different from the cladding of the inner surfaces of the sheet-like elements 100, 102 (the surfaces facing into the chamber 108). For example, the outer surfaces of the first and second sheet-like elements may be clad with an aluminum brazing alloy to allow aluminum upstanding fins or turbulence enhancement inserts to be brazed to the sheet-like elements 100, 102. Such brazing would be performed prior to welding the sheet-like elements 100, 102 together to seal the chamber 108.

[0087] Chamber 108 contains a working fluid such as water, and chamber 108 also contains a sheet of wicking material 110, which may include a wire mesh. Figure 5B and 5C As best seen in the wicking material 110, the wicking material 110 defines one or more liquid flow passages and may include a plurality of cutouts that define one or more gas flow passages 112. In the present embodiment, the wicking material 110 is elongated and extends substantially along the entire length of the chamber 108, thereby defining one or more elongated liquid flow passages 120. The cutout areas around the outer edges of the wicking material 110 may define one or more elongated gas flow passages 112. Thus, the shape of the wicking material 110 encourages the longitudinal circulation of the evaporated working fluid along the length of the two-phase cooling element 98 away from the LEDs 30, as well as the longitudinal return circulation of the condensed working fluid toward the LEDs 30.

[0088] In the present embodiment, the LEDs 30 are arranged in a plurality of linear arrays 114, each of which is disposed on one of the plurality of faces 26 of the heat diffuser element 12. However, the arrangement of the LEDs 30 may vary depending on a number of factors, including the shape and size of the heat diffuser element 12, the shape and size of the faces 26, the size of the LEDs 30, and the desired pattern of the LEDs 30 on the outer surface 18 of the heat diffuser element 12.

[0089] Each of the two-phase cooling elements 98 includes at least one evaporation zone 116 and at least one condensation zone 118. Each LED 30 is in thermal contact with one of the evaporation zones 116. In the present embodiment, the evaporation zones 116 correspond to portions of the exterior surface 18 on which the LEDs 30 are mounted, and the condensation zones 118 are spaced apart from the LEDs 30 along the exterior surface 18. For example, as can be seen in the drawings, each linear array 114 of LEDs 30 covers a portion of one of the plurality of faces 26 and extends from a point proximate the first end 20 of the heat spreader element 12 to a point intermediate between the first and second ends 20, 22. The portion of the chamber 108 of each cooling element 98 directly below the array 114 of LEDs 30 defines the approximate area of ​​the evaporation zone 116, wherein the liquid working fluid in the wicking material 110 is evaporated by the heat emitted by the LEDs 30. The condensation zone 118 is defined as the approximate area of ​​the chamber 108 of each cooling element 98 extending from the evaporation zone 116 to a point proximate the second end 22 of the heat spreader element 12. Although the two-phase cooling element 98 of this embodiment has a single evaporation zone 116 and a single condensation zone 118, this is not required. For example, the array 114 of LEDs 30 can be located between the ends 20, 22 of the heat spreader element 12, so that the two-phase cooling element 98 includes an evaporation zone 116 located between two condensation zones 118, and the two condensation zones 118 are located at opposite ends 20, 22 of the heat spreader element 12.

[0090] like Figure 5B and 5C As shown in FIG. 1 , the wicking material 110 extends through both the evaporation zone 116 and the condensation zone 118. In the evaporation zone 116, the working fluid is heated and evaporated, thereby absorbing thermal energy from the LED 30. The wicking material 110 in the evaporation zone 116 may include an increased edge surface area to enhance the transfer of the gaseous working fluid from the wicking material 110 (i.e., one or more liquid flow passages 120) to the one or more gas flow passages 112. For example, the wicking material 110 includes castellations 113 to increase its edge surface area in the evaporation zone 116, however, other shapes may be effective, including sinusoidal, triangular, etc.

[0091] The evaporated working fluid flows through one or more gas flow passages 112 toward the condensation region 118. The evaporated working fluid condenses in the condensation region 118, releasing thermal energy and thereby spreading the heat over the entire area of ​​the two-phase cooling element 98 and over the entire area of ​​each face 26. The wicking material 110 is hydrophilic and includes a large number of small voids in which capillary forces are generated. Figure 5B and 5CAs shown in FIG. 1 , condensed fluid in the condensation zone 118 is drawn into these voids and circulates back to the evaporation zone 116 through the wicking material 110 , which defines one or more liquid flow paths 120 .

[0092] One benefit of incorporating the two-phase cooling element 98 into the thermal management device 10 is that the temperature difference between the different LEDs 30 within each array is minimized and can be close to zero. Without two-phase cooling, one would expect the LEDs 30 in the center region of each array to be hotter than the LEDs located near the edge of the array. Because the frequency and wavelength of light emitted by the LEDs 30 are temperature dependent, keeping all of the LEDs 30 within a narrow temperature range will narrow the frequency and wavelength range of radiation emitted by the LEDs 30. This may be beneficial in applications that require the LED device to provide radiation of a specific frequency and / or wavelength, such as in greenhouse applications and / or in radiation curing applications.

[0093] Although the two-phase cooling element 98 produces the temperature uniformity described above without fan cooling, additional benefits can be achieved by incorporating the two-phase cooling element 98 into the thermal management device 10 and incorporating a temperature controlled fan unit 80. The fan unit 80 is operable to vary the flow rate of the cooling medium through intermittent operation and / or speed control in response to a temperature signal representing the temperature of the LEDs 30. By varying the flow of the cooling medium, the fan unit 80 can vary the heat transfer coefficient of any upstanding heat sink fins that are incorporated into the device 10 to conduct and radiate heat out of the wall 14. By doing so, the fan unit 80 can be controlled to vary the temperature of the LEDs 30 while maintaining the temperature difference within each array of the LEDs 30 at or near zero. For example, the fan unit 80 can include a temperature-responsive proportional speed control, where the control is a feedback control based on the temperature of the wall 14, the two-phase cooling element 98, and / or the LEDs 30. Because the two-phase cooling element maintains the LEDs 30 at a constant temperature, the temperature can be monitored at a single point along the length of the wall 14. Thus, the thermal management unit 10 including the two-phase cooling element 98 in combination with the temperature controlled fan unit 80 provides overall temperature uniformity and temperature variability for the LEDs 30, allowing the same LED device to provide a range of specific wavelengths depending on the specific application.

[0094] Reference now Figures 9 and 10 A heat management device 130 according to a second embodiment is described below.

[0095] Most elements of the thermal management device 130 are similar or identical to the elements of the thermal management device 10 described above. In the drawings and / or the following description, similar elements of the device 130 are identified with the same reference numerals, and the above description of similar elements of the device 10 is also applicable to the device 130. Therefore, the following description of the device 130 mainly focuses on the differences between the thermal management devices 10 and 130.

[0096] Fig. 9 The complete thermal management device 130 is shown, and Fig.10 The heat spreader element 12 is shown in a straight form.

[0097] The inner sleeve 60 and the fan unit 80 of the thermal management device 130 are the same as those of the thermal management device 10, and further description of these elements is omitted. The electronic components 30 of the thermal management device 130 are LEDs 30 arranged in a linear array 114 as in the thermal management device 10. However, Fig. 9 Also shown is a circuit board 34 on which the LEDs 30 are mounted, and a TIM layer 32 forming a thermally conductive dielectric layer between the LEDs 30 and the outer surface 18 of the heat spreader element 12. Figures 1 to 8 Not shown, but understood, the same TIM layer 32 and circuit board 34 may be provided in the thermal management device 10 .

[0098] Rather than being arranged proximate the first end 20 of the heat diffuser element 12, the linear array 114 of LEDs is shown positioned toward its second end 22. However, this is not required, and the LEDs 30 may be located anywhere on the outer surface 18 of the heat diffuser element 12 and in any arrangement.

[0099] Rather than being comprised of first and second sheet elements 100, 102, the heat diffuser element 12 is a relatively thick unitary plate structure, wherein the thickness of the wall 14 is greater than the thickness of the sheet elements 100, 102 of the thermal management device 10. In some embodiments, the wall 14 of the heat diffuser element 12 of the device 130 may have a thickness of 2 mm to 3 mm. Thus, in the device 130, the heat diffuser element 12 comprises a heat sink that absorbs and dissipates heat from the LEDs 30 over the entire area and thickness of the heat diffuser element 12.

[0100] Rather than having a turbulence enhancement insert as described above, the inner surface 16 of the wall 14 is provided with a plurality of mutually parallel, upright, longitudinally extending heat sink fins 132, wherein the heat sink fins are located in the flow space 36 between the inner surface 18 of the wall 14 and the inner sleeve 60. The heat sink fins 132 may be integrally formed with the wall 14, wherein the wall 14 and the heat sink fins 132 are integrally formed by casting, extrusion molding, and / or machining. The heat sink fins 132 absorb heat from the wall 14 by conduction and then release the heat to the cooling medium by convection. The heat sink fins 132 extend along the length of the inner surface of the wall 14 and may have a height of approximately 4 mm to 15 mm in some embodiments.

[0101] The free ends of the heat dissipating fins 132 are close to the inner sleeve 60 or in contact with the inner sleeve 60 .

[0102] Fig.10 The wall 14 (with the fins 132) is shown in a straight form, and the faces 26 are joined together along a bend line 28. In this embodiment, the bend line 28 is defined by a V-shaped notch 134 in one or both of the inner surface 16 and the outer surface 18 of the wall 14. In this embodiment, the bend line 28 is formed by opposing V-shaped notches 134 in both the inner surface 16 and the outer surface 18. These notches 134 can be formed by scoring, machining, extrusion, or casting. When the wall 14 is bent to form Fig. 9 When the multi-faceted structure is formed, the notch 134 on the inner surface 16 of the wall 14 will be at least partially closed. In other embodiments, it will be appreciated that a straight wall 14 can be used as a heat diffuser element 12 without bending, such as when the final product is a lighting panel or the like. In such an embodiment, the wall does not necessarily have to be provided with a bend line 28.

[0103] Fig.11 An alternative form of wall 14 is shown that may be used in the thermal management device 130 of the second embodiment. Fig.11 The wall 14 and Fig.10 , wherein V-shaped recesses 134 are provided in at least the outer surface 18 of the wall 14 , and optionally in the inner surface 16 , and heat dissipating fins 132 are provided along the entire length of the inner surface 16 of the wall 14 .

[0104] In addition, the outer surface 18 of the wall 14 is provided with a plurality of vertical longitudinally extending external heat sink fins 136 that are parallel to each other and can be integrally formed with the wall 14 in the same manner as the heat sink fins 132 described above. The external heat sink fins 136 conduct heat away from the outer surface 18 of the wall 14 and transfer it to the surrounding atmosphere by convection. The location of the external heat sink fins 136 is defined by the portion of the outer surface 18 of the wall 14 that is not occupied by the LEDs 30. For example, in the present embodiment, since the linear array 114 of LEDs is positioned toward the second end 22, the external heat sink fins 136 are positioned proximate to the first end 20 of the heat spreader element 12. However, as described above, the LEDs 30 can be positioned at any location and in any arrangement on the outer surface 18 of the heat spreader element 12, and therefore, the external heat sink fins 136 can be located in other areas of the outer surface 18.

[0105] Reference now Fig.12 A heat management device 140 according to a third embodiment is described below.

[0106] Many elements of the thermal management device 140 are similar or identical to elements of the thermal management device 10 described above. In the drawings and / or the following description, similar elements of the device 140 are identified with the same reference numerals, and the above description of similar elements of the device 10 is equally applicable to the device 140. Therefore, the following description of the device 140 focuses primarily on the differences between the thermal management devices 10 and 140.

[0107] Rather than having a multi-faceted configuration, the heat diffuser element 12 of the device 140 is a device having a smoothly curved wall 14 that has a smoothly circular shape when viewed in transverse cross-section. For example, the wall 14 may have a cylindrical shape and a circular cross-section and comprise a bendable layer of the heat diffuser element 12. In this embodiment, the wall 14 has no pre-formed bend lines and may be smoothly bent along any longitudinal line extending between the first end 20 and the second end 22. The inner surface 16 of the wall 14 is provided with a turbulence enhancement insert 46 comprising corrugated fins, and a set of ridges 48 are in contact with the inner surface 16 of the wall 14 and are optionally metallurgically bonded thereto. To manufacture such a heat diffuser element 12, the wall 14 and turbulence enhancement insert 46 may be assembled in a straight form and then rolled or smoothly bent into a cylindrical shape while being bent at its longitudinal side edges and secured mechanically or by metallurgical bonding. Although the illustrated thermal management device 140 does not have an inner sleeve, it will be appreciated that an inner sleeve, such as the sleeve 60 described above, may be inserted within the hollow interior of the cylindrical structure.

[0108] It will be appreciated that the wall 14 of the thermal management device 140 may include a single flexible sheet material layer, or it may include one or more two-phase cooling elements 98 including at least one first sheet element 100 and at least one second sheet element 102 .

[0109] Reference now Figures 13 to 15 A heat management device 150 according to a fourth embodiment is described below.

[0110] Many elements of the thermal management device 150 are similar or identical to elements of the thermal management devices 10 and / or 130 described above. In the drawings and / or the following description, similar elements of the device 150 are identified with the same reference numerals, and the above description of similar elements of the devices 10 and 130 is equally applicable to the device 150. Therefore, the following description of the device 150 focuses primarily on the differences between the thermal management device 150 and the previously described devices 10 and 130.

[0111] The thermal management device 150 includes a plurality of sections 152, one of which is Fig.13 14. Segment 152 includes one of the faces 26 of the multi-sided wall 14 and includes a first sheet-like element 100 and a second sheet-like element 102, which together form a two-phase cooling element 98 having an internal chamber 108 (not shown). The first sheet-like element 100 includes a flat middle portion 154 with a bendable flange 156, which is arranged along two longitudinal side edges of the flat middle portion 154. The second sheet-like element 102 of the multi-sided wall 14 can be the same as those of the device 10.

[0112] The first sheet element 100 defines the inner surface 16 of the wall 14 and is provided with upstanding fins in the form of an inner turbulence enhancement insert 46 comprising corrugated fins having a set of ridges 48 in contact with, and optionally metallurgically bonded to, the inner surface of the flat middle portion 154. The inner turbulence enhancement insert 46 extends along the entire length of the segment 152. The inner turbulence enhancement insert 46 is provided only on the inner surface of the flat middle portion 154 and not on the flange 156.

[0113] Similar to the devices 10 and 130 described above, the LED 30 is arranged at one end of a section 152 of the wall 14. The other end of the section 152 may be provided with an outer upstanding fin or turbulence enhancement insert 158 ​​which is in thermal contact with and may be metallurgically bonded to the outer surface of the flat middle portion 154 defined by the raised middle portion 106 of the second sheet element 102.

[0114] After each individual segment 152 is assembled, the multiple segments 152 are metallurgically or mechanically bonded together along their bendable longitudinal flanges 156. It will be appreciated that three or more segments 152 may be combined to provide a multi-sided thermal management device 150 having three or more sides. Fig.14 and 15 The end view of the four-sided thermal management device 150 is schematically shown, wherein: Fig.14 The embodiment has a chamfered corner forming a bent flange 156, and Fig.15 The embodiment has right angle corners due to the flange 156 being bent under the flat middle portion 154. It will be appreciated that the same segment 152 can be used to provide any number of faces 26 for the thermal management device 150, with the minimum number of faces 26 being three.

[0115] Fig.16 A partial cross-section diagram similar to Fig.10 , showing a portion of a straight wall 14, illustrating the LED 30, the circuit board 34 and the layers of the TIM layer 32, and also illustrating how the wall 14 is penetrated by holes 160 to allow the straight wall 14 to be bent into a multi-faceted structure, so that the holes 160 define bending lines 28 between adjacent faces 26.

[0116] Reference now Figure 17 to Figure 18 A heat management device 170 according to a fifth embodiment is described below.

[0117] Many elements of the thermal management device 170 are similar or identical to elements of the thermal management devices 10, 130, 140, and / or 150 described above. In the drawings and / or the following description, similar elements of the device 170 are identified with the same reference numerals, and the above description of these similar elements is equally applicable to the device 170. Therefore, the following description of the device 170 focuses primarily on the differences between the thermal management device 170 and the previously described embodiments.

[0118] Fig.17 and Fig.18 Not all features of the thermal management device 170 are shown, but only a single layer tubular heat spreader element 12 with upstanding fins attached thereto is shown. It is understood that the thermal management device 170 may also include a two-phase cooling element 98, electronic components such as LEDs, a TIM layer 32, a circuit board 34, internal electronic components 76, a fan unit 80, all as previously described.

[0119] The wall 14 of the heat diffuser element 12 is tubular, extending along a longitudinal axis L, having an inner surface 16 and an outer surface 18, longitudinally spaced first and second open ends 20, 22, and a hollow interior space 24. When viewed from the end or transverse section, the wall 14 has a plurality of faces 26, each of which is rectangular and elongated along the axis L. There are six faces 26 in the device 170, and the wall 14 has a hexagonal transverse cross-section. As previously mentioned, the wall 14 does not necessarily have to have a constant cross-section.

[0120] Upright heat dissipating fins 172 are disposed along and in thermal contact with at least one of the inner surface 16 and the outer surface 18 of the wall 14 to conduct and radiate heat away from the wall 14 of the heat spreader element 12. The upright fins 172 have free edges 174 distal to the wall 14, and the fins 172 may optionally extend perpendicularly to the wall 14 relative to the longitudinal axis L. However, they may be inclined relative to the axis L. The upright fins 172 also have fixed edges 176 along which the upright fins 172 are connected to the wall 14 directly or through a base layer 178. The upright fins 172 may be integrally formed with the base layer 178 by bending a metal sheet to form a series of transversely extending corrugations and compressing the corrugations in the longitudinal direction to form flat upright fins 172. In such a structure, the base layer 178 may include a single layer of metal and the upright fins 172 include two layers. It will be appreciated that the flat upstanding fins 172 of the device 170 may be replaced by another form of structure, such as corrugated fins or other turbulence enhancing inserts as described above.

[0121] The upstanding fins 172 of the device 170 and their free edges 174 extend substantially transverse to the longitudinal axis L. This type of fin arrangement is optimized for lateral flow of cooling medium over and between the upstanding fins 172, such as where the thermal management device 170 is incorporated into a horizontally mounted, air-cooled LED lighting device. The air will circulate upward between the upstanding fins 172 as the air absorbs heat by natural convection or with the aid of the fan unit 80.

[0122] The upstanding fins 172 on both the inner surface 16 and the outer surface 18 are arranged in a plurality of discrete groups 180, each discrete group 180 being disposed on one of the plurality of faces 26 of the wall 14. In the present embodiment, each group 180 includes a flat base layer 178 having a plurality of attached upstanding fins 172, with the width of each group 180 being equal to or slightly less than the width of each face 26. The discrete groups 180 of upstanding fins 172 are spaced apart from one another by the bends 28 between the faces 26.

[0123] Fig.17The wall 14 of the heat diffuser element 12 is shown in a straight form before being bent into a tubular shape. The bends 28 between the faces 26 extend substantially longitudinally and are formed along predefined bend lines, which may be defined by perforating, scoring or slotting the wall 14. In this embodiment, each bend line is defined by one or more apertures 182, each aperture 182 comprising an elongated slot extending substantially longitudinally.

[0124] The holes 182 not only serve to define bend lines to help form the tubular wall 14, but they also allow the cooling medium to flow between the inner and outer surfaces 16, 18 of the tubular wall 14. This may be useful in embodiments where the flow of the cooling medium through the interior space 24 of the wall 14 is not primarily longitudinal, such as in the case of incorporating the thermal management device 170 into a horizontally mounted LED lighting device. It will be appreciated that the holes 182 may also be provided in embodiments where the wall 14 does not bend along pre-formed bend lines, such as in embodiments similar to Fig.12 The thermal management device shown has a smoothly curved tubular wall 14.

[0125] Fig.17 The straight heat diffuser element 12 includes first and second side edges 184, 186 that are arranged in opposite, laterally spaced relation. The side edges 184, 186 extend substantially longitudinally. When the wall 14 is bent and folded into a tubular shape, similar to Figures 13 to 15 The flange 156 in the middle forms the side edges into an overlapping arrangement and joins them together to form a longitudinal seam.

[0126] Along the outer surface 18 of the tubular wall 14, each face 26 includes an area 188 where electronic components such as LEDs 30 will be secured to the wall 14 as described above. In the present embodiment, this area 188 is located between the ends 20, 22, and a discrete group 180 of upstanding fins 172 is provided on either side of the area 184. In the event that one or more faces 26 of the heat spreader element 12 include a two-phase cooling element 98, the area 188 will correspond to the area of ​​the evaporation zone 116, and the area of ​​the discrete group 180 of upstanding fins 172 will correspond to the area of ​​one of the condensation zones 118.

[0127] In some embodiments, upstanding fins 172 may be provided along substantially the entire length of the inner surface 16 of the tubular wall 14, including the portion of the inner surface 16 defined by the surface 188 directly opposite the LEDs 30. However, in the present embodiment, the area of ​​the wall 14 covered by the upstanding fins 172 is substantially the same on both the inner surface 16 and the outer surface 18 of the wall 14, and there are no upstanding fins 172 on the portion of the inner surface 16 corresponding to the area 188. This arrangement may be useful when the electronic components 76 are enclosed within the hollow interior space 24, in the area corresponding to the area 188.

[0128] Where the tubular wall 14 is constructed of aluminum or aluminum-clad sheet material, the upstanding fins 172 may also be constructed of aluminum and metallurgically bonded by brazing to the tubular wall 14. Where the surface of the tubular wall 14 to which the fins 172 are bonded is clad with copper or nickel, the fins 172 may include copper or may be clad with copper or nickel.

[0129] like Fig.18 As shown in FIG, the hollow interior space 24 of the wall 14 may be provided with one or more transverse walls or baffles 74 to partially or completely block the longitudinal air flow through the interior space 24. Fig.18 1 , a portion of the wall 14 is cut away to show the baffles 74. In this embodiment, there are two baffles 74, one at each end of the region 188. The electronic components 76 can be enclosed between the baffles 74, and the cooling medium enters and leaves the region between the baffles 74 through the holes 182 in the wall 14. The baffles 74 can be perforated where additional cooling medium flow is desired.

[0130] The thermal management device 170 may include a mounting flange 90 at one end 20 , 22 of the heat spreader element 12 for attachment to a base and / or a fan unit.

[0131] Although various embodiments have been described in conjunction with the present disclosure, it should be understood that certain changes and modifications may be made to the described exemplary embodiments within the scope of the present disclosure.Therefore, the embodiments discussed above are considered to be illustrative rather than restrictive.

Claims

1. A thermal management device for an electronic component, comprising: (a) a multi-sided heat diffuser element defining a longitudinal axis and comprising a longitudinally extending multi-sided wall and an interior space at least partially enclosed within the multi-sided wall, the multi-sided wall having an inner surface, an outer surface, and a longitudinally spaced first end and a second end; (b) a plurality of electronic components mounted to an outer surface of a wall of the heat spreader element; (c) a flow space for a cooling medium, the flow space being arranged in an inner space of the heat diffuser element; as well as (d) a tubular inner sleeve spaced radially inwardly from the multiple side walls of the heat diffuser element, wherein the tubular inner sleeve includes a longitudinal wall portion having a hollow interior, wherein the tubular inner sleeve further comprises a transverse wall extending across the interior of the longitudinal wall portion and provided with one or more holes to allow the flow of a cooling medium, The heat spreader element includes at least one layer of heat conductive metal, and the at least one layer of heat conductive metal can be bent from a straight shape to the multi-sidewall shape.

2. The thermal management device according to claim 1, characterized in that: Also included is a plurality of upstanding fins disposed along and in thermal contact with at least one of the inner and outer surfaces of the plurality of side walls of the heat spreader element.

3. The thermal management device according to claim 2, characterized in that: At least some of the upstanding fins have free edges extending substantially transverse to the longitudinal axis.

4. The thermal management device according to claim 1, characterized in that: The multiple side walls of the heat spreader element include at least one two-phase cooling element, wherein each of the two-phase cooling elements is a vapor chamber or a heat pipe.

5. The thermal management device according to claim 4, characterized in that: each of at least one of said two-phase cooling elements being elongated along said longitudinal axis; wherein each of at least one of the two-phase cooling elements comprises an evaporation region and a condensation region; and Wherein, each of the plurality of electronic components is located on top of and in thermal contact with an evaporation region of at least one of the two-phase cooling elements.

6. The thermal management device according to claim 5, characterized in that: Also included are a plurality of upright fins, each of the plurality of upright fins being disposed on and in thermal contact with an inner surface or an outer surface of the plurality of side walls, and Wherein, each of the upright fins is located on top of and in thermal contact with the condensation zone of one of the two-phase cooling elements.

7. The thermal management device according to claim 1, characterized in that: The one or more holes extend through the multi-sided wall to allow the cooling medium to flow between the inner and outer surfaces of the multi-sided wall.

8. The thermal management device according to claim 1, characterized in that: When viewed in transverse cross-section, at least one bendable layer of the multi-sided wall is smoothly bent so that the multi-sided wall of the heat spreader element has a smooth rounded shape.

9. The thermal management device according to claim 1, characterized in that: At least one bendable layer of the multi-sided wall is bent along a plurality of bend lines extending between a first end and a second end of the multi-sided wall such that the multi-sided wall of the heat spreader element includes a plurality of faces when viewed in transverse cross-section.

10. The thermal management device according to claim 9, characterized in that: The one or more holes extend through the multi-sided wall to allow the cooling medium to flow between the inner and outer surfaces of the multi-sided wall; Wherein, the hole is arranged along the bending line.

11. The thermal management device according to claim 10, characterized in that: Also included is a plurality of upstanding fins disposed along and in thermal contact with at least one of the inner and outer surfaces of the plurality of side walls of the heat spreader element; wherein the plurality of upright fins are arranged into a plurality of discrete groups, each discrete group of the upright fins being disposed on one surface of the plurality of side walls; and Wherein, the discrete groups of upstanding fins are spaced apart from each other by bend lines and holes between faces of the multiple side walls.

12. The thermal management device according to claim 9, characterized in that: The bend lines between the faces extend substantially longitudinally, and at least one of the bend lines is predefined by perforating, scoring or slotting the at least one bendable layer of the multi-sided wall along the bend line.

13. The thermal management device according to claim 1, characterized in that: Also includes: a first flow space for a cooling medium, the first flow space being disposed along an inner surface of the heat diffuser element, the first flow space having an inlet and an outlet spaced apart along the longitudinal axis; as well as a turbulence enhancement insert disposed in the first flow space; Wherein the turbulence enhancement insert comprises a plurality of corrugations arranged to have longitudinally oriented openings therethrough.

14. The thermal management device according to claim 13, characterized in that: the tubular inner sleeve comprising a longitudinal wall portion having a hollow interior defining a second flow space for a cooling medium, and wherein the first flow space is defined between the longitudinal wall portion of the tubular inner sleeve and the multi-side walls of the heat diffuser element; wherein the corrugations of the turbulence enhancement insert each have a top surface in thermal contact with the multiple side walls of the heat diffuser element, a bottom surface in thermal contact with the longitudinal wall portion of the tubular inner sleeve, and radially oriented side walls extending between the top and bottom surfaces.

15. The thermal management device according to claim 14, characterized in that: Also comprising one or more heat generating components, the one or more heat generating components being located inside the longitudinal wall portion of the tubular inner sleeve; Therein, the one or more holes of the transverse wall allow the cooling medium to flow through the second flow space.

16. The thermal management device according to claim 1, characterized in that: The plurality of electronic components includes a plurality of light emitting diodes (LEDs); wherein the thermal management device further comprises a fan unit, the fan unit being positioned proximate to the first end or the second end of the multi-side wall of the heat diffuser element, the fan unit being adapted to circulate the cooling medium through the interior space of the heat diffuser element; Wherein, the fan unit includes a temperature responsive proportional speed control to maintain the LEDs at a specific temperature to maintain a specific color or light output.

17. The thermal management device according to claim 1, characterized in that: The plurality of electronic components include a plurality of light emitting diodes (LEDs), and wherein the thermal management device further includes a transparent or translucent lens disposed over an outer surface of the plurality of side walls of the heat spreader element and over the LEDs.

18. A method of manufacturing the thermal management device according to claim 1, the method comprising: - providing a flat metal substrate constituting at least one bendable layer of the multi-side walls of the heat spreader element; - forming a plurality of bending lines on at least one of the inner surface and the outer surface of the flat metal substrate, wherein the plurality of bending lines are formed by scoring, punching or slotting the flat metal substrate; and - bending said flat metal substrate along said bending lines and forming a multi-sided heat spreader element, wherein said multi-sided heat spreader element comprises a plurality of faces, each of said faces being substantially flat and defined between two of said bending lines.

19. The method according to claim 18, characterized in that The method further includes mounting the electronic component on an outer surface of the flat metal substrate before the step of bending the flat metal substrate.

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