Lamp unit and manufacturing method of the same

Abstract

To provide a lamp unit which achieves improvement of heat radiation effect of heat generated by a light source, and to provide a manufacturing method of the lamp unit.SOLUTION: A lamp unit 1 includes LED modules 5 (51 to 53) serving as light sources mounted on a base 31 surface of a heat sink 3 including heat radiation fins 32. Sub heat radiation fins 9 (91 to 96) are mounted on a position adjacent to the LED modules 5 on the base 31 surface. A base plate 4 having heat conductivity higher than that of the heat sink 3 is mounted on the base 31 surface. The LED modules 5 and the sub heat radiation fins 9 are mounted on a surface of the base plate 4. The LED modules 5 and the sub heat radiation fins 9 are bonded to the base plate and these components are bonded at the same time.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a lamp unit suitable for use in a vehicle lamp, and more particularly to a lamp unit having an improved heat dissipation effect for heat generated in a light source, and a method for manufacturing the same. [Background technology]

[0002] In vehicle lamps that use light-emitting elements such as LEDs (light-emitting diodes) as light sources, heat dissipation measures are implemented to prevent the light-emitting characteristics of the light source itself from being degraded by heat generated by the light source. Patent Document 1 proposes a lamp unit in which an LED and a reflector that reflects the light emitted from the LED are mounted on a heat sink, and the heat generated by the LED and the heat conducted to the reflector are dissipated from the heat sink. The upper surface of the heat sink is configured as a mounting surface, and the LED and reflector are mounted on this mounting surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-22424 A Summary of the Invention [Problem to be solved by the invention]

[0004] The heat sink is provided with heat dissipation fins to dissipate the heat generated by the LED, but the heat dissipation fins are generally provided on the bottom or back side of the heat sink, excluding the mounting surface. Most of the heat generated by the LED is conducted through the heat sink and dissipated into the air from the heat dissipation fins, while the rest of the heat is dissipated from the mounting surface of the heat sink.

[0005] Conventionally, the mounting surface of the heat sink is not provided with any heat dissipation fins or heat dissipation structure. Therefore, it is difficult to expect a heat dissipation effect from the mounting surface, and the heat dissipation effect of the LED is not necessarily sufficient, which causes problems with the light emission characteristics of the LED. In addition, the temperature of the reflector may become excessively high due to heat from the mounting surface, causing it to deform.

[0006] An object of the present invention is to provide a lamp unit having an improved heat dissipation effect and a method for manufacturing the same. [Means for solving the problem]

[0007] The present invention provides a lamp unit including a light source mounted on a sink base surface of a heat sink equipped with heat dissipation fins, and a sub-heat dissipation fin is mounted on the sink base surface at a position adjacent to the light source. Here, it is preferable that a base plate having a higher thermal conductivity than the heat sink is mounted on the sink base surface, and the light source and the sub-heat dissipation fin are mounted on the surface of the base plate. It is also preferable that the light source and the sub-heat dissipation fin are bonded to the base plate.

[0008] In the present invention, it is preferable that a reflector that reflects light emitted from the light source is mounted on the base plate, the sub heat dissipation fins are mounted adjacent to the reflector, and a light source board for controlling the light emission of the light source is mounted on the sink base surface adjacent to the base plate, and the light source and the light source board are electrically connected.

[0009] The method for manufacturing a lamp unit of the present invention includes a step of temporarily bonding the light source and the sub-radiating fin to the surface of the base plate in a lamp unit in which a base plate is supported on a sink base surface of a heat sink equipped with radiation fins and a light source and a sub-radiating fin are mounted on the surface of the base plate, and the light source and the sub-radiating fin are simultaneously bonded and fixed to the base plate by a predetermined process. In this step, it is preferable to bond them temporarily using a thermosetting adhesive and bond and fix them by a heat treatment. Effect of the Invention

[0010] According to the present invention, a lamp unit can be obtained that has an improved heat dissipation effect from the light source mounted on the heat sink and the reflector. Also, according to the present invention, the light source and the reflector can be mounted on the heat sink in one step, improving workability. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view of an automobile equipped with a headlamp to which a lamp unit according to an embodiment is applied, as viewed from the front. [Diagram 2] FIG. 2 is a schematic exploded perspective view of a headlamp. [Diagram 3] FIG. 2 is an external perspective view of the illumination lamp unit. [Figure 4] FIG. 2 is a partially exploded perspective view of the illumination lamp unit. [Diagram 5] 1A and 1B show a lighting lamp unit, in which FIG. 1A is a plan view and FIG. [Figure 6] FIG. [Figure 7] FIG. 13 is a conceptual diagram showing the process of bonding the light source and the sub-heat dissipation fin. [Figure 8] 11A to 11C are perspective views of two modified examples of the sub heat dissipation fin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an automobile CAR equipped with a headlamp HL to which a lamp unit according to an embodiment of the present invention is applied, as viewed from the front. In this headlamp HL, an illumination lamp unit 1 capable of illuminating high beam distribution and low beam distribution, and an auxiliary lamp unit 2 such as a clearance lamp or a daytime running lamp are integrally assembled. In the following description, the front-rear direction is the direction along the front-rear direction of the headlamp HL, and the side that emits light is referred to as the front side. In addition, the left-right direction is the direction along the left-right direction of the headlamp HL.

[0013] 2 is a schematic exploded perspective view of a headlamp. The headlamp HL includes a lamp housing 100 that includes a container-shaped lamp body 101 that is open on the side that emits light, and a light-transmitting cover 102 that is attached to the front opening of the lamp body 101. A concealing extension 103 that functions as a pseudo reflector is provided inside the lamp housing 100, and a light guide 21 that constitutes an auxiliary lamp unit 2 is provided in front of the extension 103. Although detailed description is omitted, the auxiliary lamp unit 2 includes a light source such as an LED (light-emitting diode) that is not shown in the figure, and guides light emitted from the LED inside the light guide 21 and emits it from a side surface of the light guide 21 facing forward to form a lamp having a linear lamp light-emitting surface.

[0014] A horizontally long opening window 104 is formed along the upper side of the extension 103, and an illumination lamp unit 1 is disposed at a rear side of the extension 103 facing this opening window 104. This illumination lamp unit 1, which will be described in detail later, is configured with three lamps arranged in the left-right direction, each of which can be turned on and off. Here, the two lamps L1 and L2 on the right side shown in Fig. 2 are configured as lamps for low beam light distribution, and the single lamp L3 on the left side is configured as a lamp for high beam light distribution.

[0015] Fig. 3 is an external perspective view of the illumination lamp unit 1, and Fig. 4 is a partially exploded perspective view. Fig. 5(a) is a plan view, and Fig. 5(b) is a front view seen from the front with a portion of the configuration removed. The illumination lamp unit 1 includes a heat sink 3 with multiple heat dissipation fins integrally formed therewith, and a base plate 4, a light source 5, a light source substrate 6, a multi-reflector 7, and a multi-illumination lens 8 are assembled to the heat sink 3.

[0016] The heat sink 3 is made of thermally conductive die-cast aluminum and includes a rectangular, flat base 31 and a plurality of heat dissipation fins 32 integrally formed and protruding from the underside of the base 31. The heat sink 3 is disposed with the long sides of the base 31 facing the front-to-rear direction of the headlamp HL, and is fixed to and supported by the lamp body 101 by fixing members (not shown).

[0017] A base plate 4 is supported on the top surface of the base 31, covering approximately half of the area from the front side. The base plate 4 is made of a material having a higher thermal conductivity than the heat sink 3, aluminum in this case, and is formed in a rectangular flat plate shape slightly smaller than the base 31. The base plate 4 is supported in a fixed state to the base 31 at both ends in the longitudinal direction facing the left and right sides by fixing means 41 such as screws. The outer shape of the base plate 4 is not limited to a rectangle, and may be an irregular shape that surrounds the light source substrate 6 from three sides depending on the arrangement of sub-fins described later.

[0018] The light source 5 includes three LED (light emitting diode) modules 51-53 corresponding to the three lamps L1-L3. Hereinafter, the three LED modules 51-53 may be collectively referred to as the LED module 5. These three LED modules 51-53 are mounted in a central region in the left-right direction on the upper surface of the base plate 4, and at a position along the rear edge thereof. The LED modules 51-53 are arranged at required intervals in the left-right direction of the base plate 4, and each of the bottom surfaces is adhered to the upper surface of the base plate 4 with a thermosetting adhesive.

[0019] Each of the LED modules 51 to 53 has the same configuration, and includes a rectangular parallelepiped submount 50 made of an insulating material such as ceramic or resin, as shown in the external perspective view of Fig. 6, and an LED 54 is mounted on a part of the upper surface of the submount 50 with its light emitting surface facing upward. The LED 54 is composed of an LED chip 56 housed in a reflector 55 in the shape of a rectangular container, and a fluorescent material 57 that is filled in the reflector 55 so as to cover the LED chip 56 and converts the wavelength of the light emitted from the LED chip 56. For example, the LED chip 56 emits blue light, and the fluorescent material 57 emits yellow light based on the blue light, and these color lights are mixed to emit white light.

[0020] A pair of electrode pads 58 are formed on another portion of the upper surface of the submount 50. The electrode pads 58 are formed as part of a conductive layer formed inside the submount 50, and are electrically connected to the anode and cathode electrodes of the LED chip 56. The LED 54 emits light when a required amount of power is supplied via the electrode pads 58, and white light is emitted from the upper surface of the phosphor material 57, i.e., the light emission surface of the LED 54.

[0021] 4, the light source board 6 is placed in a rear area of ​​the upper surface of the base 31 of the heat sink 3 in an area facing the three LED modules 51 to 53, and is supported on the base 31 by screws or the like (not shown). A required wiring pattern 61 is formed on this light source board 6, and required electronic components are mounted thereon, which constitute a light emission control circuit that controls the light emission of the LED modules 51 to 53. This light emission control circuit is not shown in the figure.

[0022] A power supply pad 62 constituted by a part of the wiring pattern 61 is formed on a part of the surface of the light source substrate 6, and this power supply pad 62 is electrically connected to the electrode pad 58 of the LED module 5 by a bonding wire 63. The state of this electrical connection is shown in Fig. 6. Also, an edge connector 64 constituted by including another part of the wiring pattern 61 is formed on a part of the rear edge of the light source substrate 6, and the vehicle body side connector 65 shown in Fig. 3 is fitted into this edge connector 64, so that power from an on-board power source or the like is supplied to the light source substrate 6.

[0023] The multi-reflector 7 is supported by the base 31 of the heat sink 3 in a state in which it covers the upper to rear regions of the three LED modules 51 to 53. The multi-reflector 7 is integrally formed with three reflectors 71 to 73 corresponding to the three LED modules 51 to 53 arranged in a horizontal row. At least the vertical cross section of the three reflectors 71 to 73 along the front-rear direction is elliptical, and the horizontal cross section is elliptical or a curved shape close to elliptical.

[0024] The multi-reflector 7 has two support pieces 74 formed at both ends in the left and right direction along the rear edge, protruding rearward, and is supported on the upper surface of the base 31 by screws 75 penetrating the support pieces 74 in the plate thickness direction. In addition, two protrusions 76 are formed downward at both ends in the left and right direction along the lower edge of the multi-reflector 7. When the multi-reflector 7 is supported on the base 31, these protrusions 76 are inserted into two positioning holes 42 opened in the base plate 4, and position the multi-reflector 7 relative to the base plate 4. In other words, the three reflectors 71 to 73 are positioned relative to the three corresponding LED modules 51 to 53, and the light reflecting surfaces of the reflectors 71 to 73 are positioned in a predetermined position and direction relative to the light emitting surfaces of the corresponding LED modules 51 to 53.

[0025] A total of six sub-heat dissipation fins 9 (91-96) are mounted on the upper surface of the base plate 4, three on each of the left and right side regions that sandwich the multi-reflector 7 in the longitudinal direction. The sub-heat dissipation fins 9 are formed from a material with a thermal conductivity similar to that of the base plate, in this case the same aluminum as the base plate 4, and each sub-heat dissipation fin 9 is formed by bending an aluminum plate into an L-shape and having a bottom piece 9b and a side piece 9s. Each sub-heat dissipation fin 9 is fixed with a thermosetting adhesive with the bottom piece 9b in close contact with the upper surface of the base plate 4.

[0026] Each sub-heat dissipation fin 9 is arranged in parallel at a required interval along the longitudinal direction of the base plate 4, in both side regions on the upper surface of the base plate 4 sandwiching the multi-reflector 7 on the left and right, with its longitudinal direction facing the front-to-rear direction, i.e., its longitudinal direction facing the short side direction of the base plate 4.

[0027] In addition, the length of the inner sub-radiation fins 9 that are closer to the multi-reflector 7 is shorter than that of the outer sub-radiation fins. That is, the lengths of the sub-radiation fins are as follows: 91>92>93, 96>95>94. The front ends of the sub-radiation fins 91-96 are set back in this order. This prevents the sub-radiation fins 9 from blocking the light that is reflected by the multi-reflector 7 and emitted toward a desired area. The height of each sub-radiation fin 9 is not particularly limited, but is set as high as possible within the range of the height allowed for the lamp unit 1. This increases the radiation area of ​​the sub-radiation fins 9, enhancing the radiation effect.

[0028] The multi-illumination lens 8 is integrally formed with three lenses 81-83 aligned in the left-right direction. Each of these lenses 81-83 is formed with a required light refraction characteristic, and is configured to irradiate the light of each of the LED modules 51-53 reflected by each of the reflectors 71-73 with a required light distribution. The multi-lens 8 is supported at its periphery by a frame-shaped lens holder 80, and is fixed to the front side of the heat sink 3 by a fixing piece 84 provided on the lens holder 80 with a screw 85. When the multi-illumination lens 8 is fixed, each of the lenses 81-83 is disposed to face the corresponding LED modules 51-53 and reflectors 71-73. The lens holder 80 may be formed integrally with the multi-lens 8.

[0029] In this embodiment, the lens holder 80 is provided with a shade (not shown) made of a non-transparent material at a portion corresponding to the two lenses 81, 82 on the right side of Figures 3 and 4. This shade is configured to block a portion of the light transmitted through the projection lenses 81, 82, i.e., the light projected in the horizontal direction or above. On the other hand, no shade is formed on the projection lens 83.

[0030] Here, the light sources 5 mounted on the base plate 4, i.e., the LED modules 5 (51-53) and the sub-heat dissipation fins 9, are attached to the base plate by adhesive. Thermosetting adhesives are used for both of these adhesives. Therefore, the process of manufacturing the lamp unit 1 requires a process of mounting the LED modules 5 and the sub-heat dissipation fins 9 on the base plate 4, but in this embodiment, these processes can be consolidated into one process.

[0031] For example, as shown in the conceptual diagram of Fig. 7, three LED modules 5 are temporarily attached with a thermosetting adhesive to required locations on the upper surface of a base plate 4, and six sub heat dissipation fins 9 are also temporarily attached in the same manner. Fig. 7 shows a state in which two LED modules 51, 52 and three sub heat dissipation fins 91-93 on the right side are temporarily attached, and one LED module 51 and three sub heat dissipation fins 94-96 on the left side are about to be temporarily attached.

[0032] Then, the base plate 4 to which all the LED modules 5 and sub-heat dissipation fins 9 have been temporarily attached is heated in a heating device (not shown) to harden the thermosetting adhesive, thereby simultaneously bonding and fixing the LED modules 5 and sub-heat dissipation fins 9 to the base plate 4. Therefore, in lamp units in which the LED modules 5 have previously been mounted on the heat sink 3 with a thermosetting adhesive, the sub-heat dissipation fins 9 can now be mounted at the same time as the LED modules 5 are mounted, so there is no increase in the number of work steps.

[0033] In the lamp unit having the above configuration, the three LED modules 51-53 emit light based on the control of the light emission control circuit, and when each of them emits white light, the white light emitted from each of the LED modules 51-53 is reflected forward by the corresponding reflectors 71-73. The white light from the two LED modules 51 and 52 on the right side of FIG. 3 is reflected by the reflectors 71 and 72 of the multi-reflector 7, and then part of it is blocked by the shade. As a result, the light that is to be projected horizontally or upward from the lenses 81 and 82 of the projection lens 8 is blocked, and a low-beam light distribution pattern having a required cutoff line is projected forward of the automobile. Furthermore, when the one LED module 53 on the left side emits light, this white light is reflected by the reflector 73, and then additional light is projected by the lens 83 toward the upper area of ​​the cutoff line of the low-beam light distribution pattern, and a high-beam light distribution pattern is projected.

[0034] Heat is generated as the LED module 5 emits light. Most of the generated heat is transferred from the submount 50 of the LED module 5 to the base plate 4. The transferred heat is further transferred to the heat sink 3 and dissipated from the heat dissipation fins 32 of the heat sink 3. Since the base plate 4 has a higher thermal conductivity than the heat sink 3, the heat of the LED module 5 is quickly transferred to the periphery of the base plate 4, and from there is quickly transferred to the entire heat sink 3. This enhances the heat dissipation effect of the heat sink 3. In addition, the heat transferred to the base plate 4 is also transferred to the sub heat dissipation fins 9, and is dissipated from the six sub heat dissipation fins 91 to 96. By disposing the sub heat dissipation fins 9 in this way, the substantial surface area of ​​the base plate 4 is expanded, and the heat dissipation effect is enhanced compared to when the base plate 4 is used alone.

[0035] On the other hand, heat that is not directly transferred from the LED module 5 to the base plate 4 is transferred by radiation to the multi-reflector 7 covering the LED module 5. When such heat transfer to the multi-reflector 7 occurs, the transferred heat is reflected back from the multi-reflector 7 toward the LED module 5, which causes the temperature of the LED module 5 to rise.

[0036] In this embodiment, the sub-heat dissipation fins 9 are disposed adjacent to the positions sandwiching the multi-reflector 7, so that the heat transferred to the multi-reflector 7 is transferred at a high rate by radiation to the adjacent sub-heat dissipation fins 9 and dissipated from there. Therefore, the heat reflected back from the multi-reflector 7 to the LED module 5 is reduced, and the LED module 5 is prevented from being heated.

[0037] In the embodiment, the sub-radiating fin 9 is formed in an L-shape by the bottom piece 9b and the side piece 9s, and therefore can be easily manufactured by bending a plate material. On the other hand, the weight balance of the sub-radiating fin 9 in the width direction, i.e., in the direction in which it is bent into an L-shape, cannot be said to be uniform. Therefore, when the sub-radiating fin 9 is temporarily attached to the base plate 4, the sub-radiating fin 9 is likely to fall due to external force, vibration, or the like, and the bonding work to prevent this may become complicated.

[0038] Therefore, as a preferred embodiment of the sub-radiation fin 9, a notch 9c is made in a part of a bottom piece 9b of an L-shaped sub-radiation fin, and the notch 9c is bent in the opposite direction to form an inverted T-shaped sub-radiation fin 9A, as shown in Fig. 8(a). Alternatively, a sub-radiation fin 9B may be formed by bending a plate material into a U-shape with a flat bottom surface, as shown in Fig. 8(b). In both of the sub-radiation fins 9A and 9B, the weight balance in the width direction at the bottom piece 9b is stabilized, so that the sub-radiation fin 9 can be prevented from falling during temporary bonding or heat treatment, improving workability.

[0039] The shape of the sub-heat dissipation fins 9 is not limited to that of the embodiment. In addition, the position where the sub-heat dissipation fins are mounted is not limited to both sides of the LED module or the multi-reflector as in the embodiment, but is preferably as close as possible to the LED module or the multi-reflector.

[0040] In addition, the adhesive used to bond the LED module and the sub-radiating fin does not necessarily have to be a thermosetting adhesive, and may be, for example, an adhesive that hardens over time even at room temperature. Even in this case, the LED module and the sub-radiating fin can be mounted simultaneously in a single process, simplifying the work process.

[0041] In the embodiment, a base plate is disposed on the base of the heat sink, and an LED module and sub-heat dissipation fins are mounted on this base plate, but if a satisfactory heat dissipation effect can be obtained with the heat sink alone, the base plate may be omitted, and the LED module and heat dissipation fins may be mounted directly on the base of the heat sink.

[0042] In the embodiment, the heat sink 3 is made of die-cast aluminum, but it may be made of a flat metal plate as a base, and a folded metal plate may be fixed as a heat dissipation fin. The metal plate may be fixed by any known technique such as caulking, welding, or screw fixing.

[0043] In the embodiment, an example of an LED module is described as a light source, but the present invention can be applied to any light source that generates heat. For example, it may be a light emitting element including a discrete type or chip type LED. In addition, in the embodiment, the present invention is applied to a lamp unit having three light sources and a plurality of lamps integrally provided with three reflectors and lenses, but it is also possible to apply the present invention to a lamp unit having one light source and composed of one reflector and irradiation lens. In addition, the lamp unit is not limited to a lamp unit of an illumination lamp, but can also be applied to a lamp unit of an auxiliary lamp. [Explanation of symbols]

[0044] 1. Lighting lamp unit 2 Auxiliary Lamp Unit 3. Heat sink 4 Base plate 5 LED module (light source) 6 Light source board 7 Multi-Reflecta 8 Multi-illumination lens 9, 9A, 9B Sub heat dissipation fin 31 Base 32 Heat dissipation fin 51~53 LED Module 71~73 Reflector 81~83 Lens 91~96 Sub heat sink fin HL Headlamp

Claims

1. A lamp unit having a light source mounted on a sink base surface of a heat sink having heat dissipation fins, characterized in that a sub-heat dissipation fin is mounted at a position adjacent to the light source on the sink base surface.

2. 2. The lamp unit according to claim 1, wherein a base plate having a thermal conductivity higher than that of the heat sink is mounted on a surface of the sink base, and the light source and the sub-heat dissipation fins are mounted on a surface of the base plate.

3. 3. The lamp unit according to claim 2, wherein the light source and the sub-heat dissipation fins are bonded to the base plate.

4. 4. The lamp unit according to claim 3, wherein the sub-heat dissipation fin has a bottom piece and a side piece, and the bottom piece is bonded to the base plate.

5. The lamp unit according to claim 4 , wherein the cross-sectional shape of the sub heat dissipation fin is formed to be any one of an L-shape, an inverted T-shape, and a U-shape.

6. 3. The lamp unit according to claim 2, wherein a reflector that reflects the light emitted from the light source is mounted on the base plate, and the sub heat dissipation fin is mounted at a position adjacent to the reflector.

7. The lamp unit according to claim 2 , wherein a light source board for controlling the light emission of the light source is mounted on the sink base surface at a position adjacent to the base plate, and the light source and the light source board are electrically connected.

8. A method for manufacturing a lamp unit in which a base plate is supported on a sink base surface of a heat sink having heat dissipation fins, and a light source and a sub-heat dissipation fin are mounted on the surface of the base plate, the method comprising temporarily bonding the light source and the sub-heat dissipation fin to the surface of the base plate, and simultaneously bonding and fixing the light source and the sub-heat dissipation fin to the base plate by a specified process.

9. 9. The method for manufacturing a lamp unit according to claim 8, further comprising the steps of: temporarily bonding the lamp unit using a thermosetting adhesive; and then bonding and fixing the lamp unit by heat treatment.

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