Heat sink, light-emitting module, and method of producing heat sink

Abstract

Provided is a novel heat sink for which a bending process has been devised. A heat sink 24 is configured by folding a single metal plate, and comprises: a plurality of folded surfaces 24a on which a substrate is to be placed; and U-shaped fins 24b provided so as to interconnect adjacent folded surfaces 24a. The U-shaped fins 24b may have a ventilation hole 24d provided to a U-shape bottom surface 24c. The bottom surface 24c may be provided so that a perpendicular line X1 of the bottom surface and a perpendicular line X2 of the folded surfaces 24a have a twisted positional relationship.

Description

Heat sink, light emitting module, and method for manufacturing the heat sink

[0001] The present invention relates to a heat sink.

[0002] Conventionally, heat sinks for dissipating heat from a light source have been known that are partially or entirely made by bending a single sheet of metal. For example, a heat sink has been devised that includes a heat source mounting plate on the surface of which a heat source is attached, and a corrugated heat dissipation plate formed continuously with the heat source mounting plate (see Patent Document 1).

[0003] JP 2012-234909 A

[0004] However, in the above-mentioned heat sink, a heat dissipation plate consisting of multiple fins extends from one side of a rectangular heat source mounting plate, and the path for the heat generated by the heat source attached to the heat source mounting plate to dissipate to the fins of the heat dissipation plate is long, so it cannot necessarily be said that heat dissipation can be performed efficiently.

[0005] The present invention has been made in view of the above circumstances, and one of its objects is to provide a new heat sink with an improved bending process.

[0006] In order to solve the above problems, one embodiment of the heat sink of the present invention is a heat sink constructed by bending a single metal plate, and has multiple bending surfaces on which substrates are placed, and U-shaped fins arranged to connect adjacent bending surfaces.

[0007] According to this aspect, it is possible to realize a heat sink on which a substrate can be placed and which has U-shaped fins integrally provided with the bent surface.

[0008] The U-shaped fins may have ventilation holes on the bottom surface of the U. This allows air to flow in and out not only between the fins but also from the bottom surface, improving the heat dissipation effect.

[0009] The bottom surface may be provided so that a perpendicular line to the bottom surface and a perpendicular line to the bent surface are in a twisted positional relationship, which makes it easier for air to flow in a direction that intersects with the perpendicular line to the substrate.

[0010] The bending surface may be a rectangular plane, and the U-shaped fin may have a first U-shaped fin connected to one side of the rectangle and a second U-shaped fin connected to the other side opposite the one side.

[0011] The bottom surface of the U-shape of the first U-shaped fin and the bottom surface of the U-shape of the second U-shaped fin may be disposed across a diagonal line of the rectangular plane, thereby realizing a heat sink with vent holes on both sides of the bent surface on which the substrate is placed.

[0012] Another aspect of the present invention is a light-emitting module. The light-emitting module includes a heat sink formed by bending a single metal plate and having a plurality of bent surfaces and U-shaped fins provided to connect adjacent bent surfaces, a substrate having one surface mounted on the plurality of bent surfaces, and a light-emitting element mounted on the other surface of the substrate. The light-emitting element is arranged so that the other surface of the substrate overlaps with the bent surface when viewed from the front.

[0013] According to this aspect, the bent surface of the heat sink is disposed on the rear surface side of the light emitting element, so that heat from the light emitting element can be easily transferred to the heat sink.

[0014] Another aspect of the present invention is a method for manufacturing a heat sink, comprising the steps of: preparing a metal plate from which a rectangular portion is punched out to allow multiple bending processes; folding the metal plate in half in a predetermined direction to form multiple bent surfaces; and folding the metal plate in a direction different from the predetermined direction multiple times to form multiple U-shaped fins. The U-shaped fins are arranged to connect adjacent bent surfaces.

[0015] According to this embodiment, a heat sink having a plurality of U-shaped fins that contribute to heat dissipation can be manufactured by bending a single metal plate.

[0016] Any combination of the above components, and conversion of the present invention between a manufacturing method, a lighting fixture or lighting device, a light emitting module, a light source, etc. are also valid aspects of the present invention.

[0017] According to the present invention, a new heat sink can be provided that utilizes an improved bending process.

[0018] FIG. 1 is a longitudinal sectional view showing an example of a vehicle lamp capable of mounting a lighting control module according to the present embodiment. FIG. 2 is a perspective view of a heat sink according to the present embodiment. FIG. 3 is a front view of the heat sink shown in FIG. 2 as seen from direction A. FIG. 4 is a top view of the heat sink shown in FIG. 2 as seen from direction B. FIG. 5 is a top view of a metal plate before being bent into a heat sink according to the present embodiment. FIG. 6 is a front view of a light-emitting module according to the present embodiment. FIG. 7 is a perspective view of a light-emitting module according to the present embodiment. FIG. 8(a) to FIG. 8(c) are schematic diagrams for explaining a method for manufacturing a heat sink according to the present embodiment. FIG. 9(a) to FIG. 9(b) are schematic diagrams for explaining a method for manufacturing a heat sink according to the present embodiment.

[0019] The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0020] (Vehicle Lamp) Fig. 1 is a longitudinal cross-sectional view showing an example of a vehicle lamp that can be equipped with a lighting control module according to this embodiment. The headlamp 10 shown in Fig. 1 is one of left and right headlamp as a vehicle lamp. These headlamp 10 are attached to both sides in the vehicle width direction at the front of the vehicle, and these headlamp 10 illuminate the area ahead of the vehicle.

[0021] As shown in FIG. 1, the headlamp 10 has an exterior formed by a lamp body 12 that is open at the front and a front cover 14 that serves as a surface cover that covers the opening of the lamp body 12.

[0022] The lamp body 12 is composed of a rear wall 12a that stands upright in the vertical direction and a peripheral wall 12b that projects forward (to the left in FIG. 1 ) from the peripheral edge of the rear wall 12a. The rear wall 12a extends laterally (perpendicular to the plane of the paper in FIG. 1 ) while maintaining a constant height, and the peripheral wall 12b cooperates with the rear wall 12a to define a storage space 16, and the tip of the peripheral wall 12b forms a horizontally elongated opening 18 in the storage space 16.

[0023] The front cover 14 is detachably attached to the tip of the peripheral wall 12b of the lamp body 12. As a result, the front cover 14 and the lamp body 12 form a lamp housing, and a sealed lamp chamber 20 is formed inside the lamp housing. The front cover 14 is translucent, and light emitted in the lamp chamber 20 is irradiated to the outside through the front cover 14. A resin lens is used for the front cover 14 in this embodiment.

[0024] An LED unit 22 is disposed inside the lamp chamber 20. As shown in Fig. 1, the LED unit 22 includes a metal heat sink 24 serving as a conductive base. The heat sink 24 according to this embodiment integrally includes a plate-shaped metal support plate 26 attached to the LED unit 22 and a heat dissipation fin 28. The metal support plate 26 and the heat dissipation fin 28 may be formed as a single component.

[0025] The metal support plate 26 is supported by the rear wall 12a of the lamp body 12 via aiming screws 30 and the like, and the plate surface of the metal support plate 26 faces the front-rear direction and is disposed spaced forward from the rear wall 12a. The heat dissipation fins 28 are attached to the rear surface of the metal support plate 26, and are cooled by a heat dissipation fan 32 attached to the heat sink 24.

[0026] The LED unit 22 includes a cylindrical lens holder 34 and a projection lens 36 attached to the lens holder 34. The rear end of the lens holder 34 is attached to the front of the metal support plate 26, and the front end of the lens holder 34 extends forward. The projection lens 36 is attached to the front end of the lens holder 34, and thus the projection lens 36 is positioned on an optical axis L extending in the fore-and-aft direction of the vehicle. A front cover 14 is disposed in front of the projection lens 36. An extension reflector 38 is disposed around the projection lens 36 and the lens holder 34.

[0027] The LED unit 22 includes a light-emitting module 40. The light-emitting module 40 includes a resin circuit board 42, a plurality of light-emitting diodes (hereinafter referred to as LEDs) 44, and a power supply connector 46. The circuit board 42 is disposed within the lens holder 34, aligned with the front surface of the metal support plate portion 26, with a board surface 42a of the circuit board 42 facing forward. The circuit board 42 is disposed toward the lower side within the lens holder 34, and a power supply circuit (not shown) is formed on the board surface 42a.

[0028] The plurality of LEDs 44 are attached to an upper portion of the board surface 42a of the circuit board 42. The plurality of LEDs 44 are arranged as a planar light source that emits light, side by side in the vehicle width direction with their light-emitting surfaces facing forward of the vehicle, and in this embodiment, each LED 44 is configured such that a fluorescent layer is provided on the LED chip so as to emit white light.

[0029] The power supply connector 46 is attached to the lower portion of the board surface 42a. A power supply (not shown) is connected to the power supply connector 46 via an LED driver module (LDM) 50 using a wire harness 48, and each LED 44 is connected via a power supply circuit (not shown) on the board surface 42a. The LED driver module 50 is disposed in the lower portion of the lamp body 12 and includes a metal case 52 serving as a conductive case and a lighting control circuit board 54 housed within the metal case 52. The power supply connector 46 and the power supply (not shown) are connected via the lighting control circuit board 54 in the metal case 52, and the lighting and extinguishing of the plurality of LEDs 44 is controlled by the lighting control circuit board 54.

[0030] (Heat sink) Fig. 2 is a perspective view of a heat sink according to this embodiment. Fig. 3 is a front view of the heat sink shown in Fig. 2 as seen from direction A. Fig. 4 is a top view of the heat sink shown in Fig. 2 as seen from direction B. Fig. 5 is a top view of a metal plate before being bent into a heat sink according to this embodiment.

[0031] When manufacturing the heat sink 24, as shown in Fig. 5, a rectangular metal plate 56 is prepared with predetermined areas (slits 56a, corners 56b, and round holes 56c) punched out so that the heat sink 24 can be folded multiple times. The metal plate 56 is made of aluminum, for example. The thickness of the metal plate 56 is, for example, approximately 1 to 3 mm, and may be in the range of 1.5 to 2.5 mm, taking into account strength and workability.

[0032] The bending method will be described later, but the heat sink 24 shown in Figures 2 to 4 is formed by bending a single metal plate 56. The heat sink 24 has multiple bent surfaces 24a on which substrates are placed and U-shaped fins 24b that connect adjacent bent surfaces 24a. The five bent surfaces 24a may be bent on both sides, such as the three central surfaces, or may be bent on only one side at each end. The five bent surfaces 24a form part of the same plane, allowing for stable placement of substrates and realizing a heat sink 24 in which the U-shaped fins 24b are integrally formed with the bent surfaces 24a.

[0033] The U-shaped fins 24b have ventilation holes 24d on the bottom surface 24c of the U. This allows air to flow in and out not only through gaps 24e between the fins 24b but also through the bottom surface 24c, improving the heat dissipation effect.

[0034] The bottom surface 24c is provided so that a perpendicular line X1 to the bottom surface 24c and a perpendicular line X2 to the bent surface 24a are in a twisted positional relationship, which makes it easier for air to flow in a direction intersecting the perpendicular line to the substrate placed on the bent surface 24a (the direction of the perpendicular line X1).

[0035] The bending surface 24a may be a rectangular plane, and the U-shaped fin 24b may have a first U-shaped fin 24b1 connected to one side of the rectangle and a second U-shaped fin 24b2 connected to the other side opposite the one side (see Figure 3).

[0036] The U-shaped bottom surface 24c1 of the first U-shaped fin 24b1 and the U-shaped bottom surface 24c2 of the second U-shaped fin 24b2 are disposed across the diagonal of the common rectangular plane (folded surface 24a), thereby realizing a heat sink 24 with ventilation holes 24d on both sides of the folded surface 24a on which the substrate is placed.

[0037] The U-shaped fin 24b has two flat surfaces 24f bent from specific sides of a rectangular flat surface (bottom surface 24c) toward the depth of the page (see FIG. 4). In other words, the two opposing flat surfaces 24f are connected by the bottom surface 24c, thereby forming the fin 24b with a U-shaped cross section. In this embodiment, at least a portion of the bottom surface 24c connecting the two flat surfaces 24f includes a flat shape, but the portion of the bottom surface 24c may be formed as a curved surface without including a flat surface.

[0038] (Light-Emitting Module) Fig. 6 is a front view of a light-emitting module according to the present embodiment. Fig. 7 is a perspective view of the light-emitting module according to the present embodiment. A light-emitting module 40 according to the present embodiment includes a heat sink 24, a circuit board 42 having a back surface 42b placed on a plurality of bent surfaces, and a plurality of light-emitting elements mounted on a board surface 42a of the circuit board 42. The light-emitting elements according to the present embodiment are LEDs 44. As shown in Fig. 6, the LEDs 44 are arranged so as to overlap the bent surfaces 24a when the board surface 42a of the circuit board 42 is viewed from the front. As a result, the bent surfaces 24a of the heat sink 24 are arranged on the back surface side of each of the LEDs 44, making it easier for heat from the LEDs 44 to be transferred to the heat sink 24.

[0039] (Method of Manufacturing Heat Sink) Figures 8(a) to 8(c) are schematic diagrams for explaining a method of manufacturing a heat sink according to this embodiment. Figures 9(a) and 9(b) are schematic diagrams for explaining a method of manufacturing a heat sink according to this embodiment. Note that the ventilation holes 24d are not shown in each figure.

[0040] As described above, the metal plate 56 shown in FIG. 5 is prepared, and as shown in FIG. 8( a), the portions that will become the bending surfaces 24a are sandwiched between the portions on both sides and bent 90 degrees to fold the plate in half. Next, as shown in FIG. 8( b), the bending surfaces 24a at both ends are bent outward by 90 degrees. Next, as shown in FIG. 8( c), the second and fourth bending surfaces 24a are bent outward by 90 degrees. Furthermore, as shown in FIG. 9( a), the bending surfaces 24a at both ends are bent inward by 90 degrees. Finally, as shown in FIG. 9( b), the second and fourth bending surfaces 24a are bent inward by 90 degrees.

[0041] In this way, by bending the metal plate 56 multiple times in directions different from the predetermined direction, multiple U-shaped fins 24b are formed. The U-shaped fins 24b are provided so as to connect adjacent bent surfaces 24a. In this way, by bending a single metal plate 56, it is possible to manufacture a heat sink 24 having multiple U-shaped fins 24b that contribute to heat dissipation.

[0042] The heat sink 24 described above is easier to manufacture and requires less material cost than cast parts such as aluminum die-casting. Furthermore, by devising the punching and bending methods, a three-dimensional heat sink 24 with a large heat dissipation area can be manufactured from a rectangular aluminum plate, which allows for a larger number of aluminum plates to be cut out from a large aluminum plate.

[0043] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations and substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to make modifications to the embodiments such as various design changes, and such modified embodiments are also included in the scope of the present invention.

[0044] This international application claims priority based on Japanese Patent Application No. 2023-117066, filed on July 18, 2023, the entire contents of which are incorporated herein by reference.

[0045] The above descriptions of specific embodiments of the present invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications and variations will be apparent to those skilled in the art in light of the above description.

[0046] 10 Headlamp, 22 LED unit, 24 Heat sink, 24a Bent surface, 24b Fin, 24c Bottom surface, 24d Ventilation hole, 40 Light-emitting module, 42 Circuit board, 42a Board surface, 42b Back surface, 44 LED, 46 Power supply connector, 56 Metal plate, 56a Slit

Claims

1. A heat sink constructed by bending a single metal plate, characterized in that it has multiple folded surfaces on which substrates are placed, and U-shaped fins connecting adjacent folded surfaces.

2. The heat sink according to claim 1, wherein said U-shaped fin has ventilation holes on the bottom surface of the U-shape.

3. The heat sink according to claim 2, wherein the bottom surface is provided so that a perpendicular line to the bottom surface and a perpendicular line to the bent surface are in a twisted positional relationship.

4. A heat sink as described in any one of claims 1 to 3, characterized in that the bent surface is a rectangular plane, and the U-shaped fin has a first U-shaped fin connected to one side of the rectangle, and a second U-shaped fin connected to the other side opposite the one side.

5. A heat sink as described in claim 4, characterized in that the bottom surface of the U-shape of the first U-shaped fin and the bottom surface of the U-shape of the second U-shaped fin are arranged on either side of a diagonal line of the rectangular plane.

6. A light-emitting module comprising: a heat sink having a plurality of folded surfaces and U-shaped fins arranged to connect adjacent folded surfaces, the heat sink being constructed by folding a single metal plate; a substrate having one surface placed on the plurality of folded surfaces; and a light-emitting element mounted on the other surface of the substrate, the light-emitting element being positioned so as to overlap the folded surfaces when the other surface of the substrate is viewed from the front.

7. A method for manufacturing a heat sink, comprising the steps of: preparing a metal plate from which a rectangular portion is punched out to allow multiple folding processing; folding the metal plate in half in a predetermined direction to form multiple folding surfaces; and folding the metal plate multiple times in a direction different from the predetermined direction to form multiple U-shaped fins, wherein the U-shaped fins are arranged to connect adjacent folding surfaces.

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