JP2018082021A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus having a heat release part ensuring sufficient heat dissipation effect even with a small number of components, and capable of suppressing leakage of heat transmission grease.SOLUTION: An electronic apparatus having a heating element includes a board mounting an element, a housing section for housing the board while exposing the element non-mounting surface of the board, and heat release section. The heat release section has a fixed part to be fixed to the side of the housing section, and a heat receiving section having a face opposing the element non-mounting surface so as to cover the element non-mounting surface, and the heat receiving section has a grease pool. Heat conduction from the board to the heat release section becomes more effective because of the existence of grease in the grease pool, thus improving heat reception and heat release effect by the heat release section. The grease pool may have a protrusion of closed loop. The fixed part may be fixed to press the heat receiving section against the element non-mounting surface.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electronic device, and more particularly to an electronic device having an element that generates heat.

  A heat radiation fin may be used for heat radiation from an electronic device having an element that generates heat. FIG. 7 shows an electronic device 100 as a conventional example of such an electronic device. 7A is a perspective view of the electronic device 100, FIG. 7B is a plan view of the electronic device 100, FIG. 7C is a VIIC-VIIC cross-sectional view of the electronic device 100 of FIG. FIG. 7D is a VID-VID cross-sectional view of the electronic device 100 of FIG. The electronic device 100 illustrated in FIG. 7 includes a surface of the substrate 101 opposite to the surface on which the element 101a that generates heat is mounted, and a heat sink 102 having a plurality of heat dissipation fins on the side opposite to the heat dissipation fins. The heat transfer gel sheet 103 is sandwiched between the surfaces, the cover 104 is covered from the surface of the heat sink 102 on the side of the heat radiating fins, and the holes 104a on the side surface of the cover 104 are hung by the claws 105a of the housing 105. The cover 104 has a plurality of leaf springs 104 b, and the plurality of leaf springs 104 b exerts a force that presses the heat sink 102 against the substrate 101. Thereby, the element non-mounting surface of the substrate 101, the heat transfer gel sheet 103, and the surface of the heat sink 102 on the side opposite to the heat dissipating fins are in close contact with each other, and the heat transfer effect between them can be enhanced.

  However, since the heat radiating fins are used, the size of the entire electronic device is increased. Further, since the cover 104 having the leaf spring 104b is used, the number of parts is increased. Furthermore, since the heat transfer gel sheet 103 is used, the cost increases accordingly. When heat transfer grease is used instead of the heat transfer gel sheet 103, the gap between the substrate 101 and the heat sink 102 is pressed by the action of the leaf spring 104b, so that the heat transfer grease is reduced from there. Extruded to the outside, the heat dissipation function deteriorates, and the protruding heat transfer grease causes poor appearance.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electronic device that has a heat radiating portion that can obtain a sufficient heat radiating effect even with a small number of parts and can suppress leakage of heat transfer grease. There is to do.

The inventors of the present invention have intensively studied to solve the above problems, and as a result, have arrived at the various aspects of the present invention as follows.
That is, the electronic device according to the first aspect of the present invention is an electronic device having a heat generating element, and a substrate on which the element is mounted, and a storage unit that stores the substrate by exposing the element non-mounting surface of the substrate. A heat dissipating part, and the heat dissipating part has a fixed part fixed to the side surface of the storage part, and a heat receiving part having a surface facing the element non-mounting surface so as to cover the element non-mounting surface. The heat receiving part is an electronic device having a grease reservoir.
According to said structure, the heat conduction from a board | substrate to a thermal radiation part is performed more effectively by presence of the grease inside a grease reservoir, and the effect of the heat reception and thermal radiation by a thermal radiation part is improved.

According to the second aspect of the present invention, in the electronic device, the grease pool has a closed loop-shaped protrusion. Thereby, a grease pool as a closed space having a predetermined volume can be formed. Moreover, it is possible to suppress the leakage of grease from the grease reservoir to the outside by the closed loop-shaped protrusion.
According to the third aspect of the present invention, in the electronic device, the fixed part is fixed so as to press the heat receiving part against the element non-mounting surface. Thereby, since the protrusion part of a heat receiving part can be pressed with respect to an element non-mounting surface, the sealing property of a grease pool can be improved and the effect which suppresses the leakage of grease is heightened.

According to the fourth aspect of the present invention, in the electronic device, the side surface of the storage portion has a protrusion, and the fixed portion has a hole that engages with the protrusion.
According to the fifth aspect of the present invention, in the electronic device, the heat receiving portion and the storage portion form a case. Thereby, since the heat receiving part of a thermal radiation part forms a part of case, it can contribute to reducing the number of parts as a whole.

According to the sixth aspect of the present invention, in the electronic device, the heat dissipation part is a single plate-like member. With such a configuration, the electronic device is more compact than a configuration in which the heat dissipating part has a fin shape, and the manufacturing cost of the electronic device can be reduced.
According to the seventh aspect of the present invention, in the electronic device, the fixed portion has a shape along the side surface of the storage portion. Thereby, an electronic device becomes compact.

  According to the eighth aspect of the present invention, in the electronic device, the storage portion has a rectangular parallelepiped shape, and the heat dissipation portion is adjacent to the one surface of the rectangular parallelepiped shape of the storage portion and the one surface. Cover another two or three faces that fit. Thereby, although a heat radiating part is a compact shape, it can have a wide area for heat receiving and heat radiation.

FIG. 1 is an exploded perspective view of a vehicle lighting device according to an embodiment of the present invention. FIG. 2 is a perspective view of the vehicle lighting device according to the embodiment. FIG. 3 is a perspective view of the vehicular illumination device of FIG. 2 viewed from the back side. FIG. 4A is a view of the housing of the vehicle lighting device according to the embodiment as seen from the reflecting portion side, and FIG. 4B is a view of the housing as seen from the substrate storage portion side. 5A is a plan view of the back side of the vehicle lighting device according to the embodiment, and FIG. 5B is a VB-VB sectional view of the vehicle lighting device of FIG. 5A. (C) is a VC-VC cross-sectional view of the vehicular illumination device of FIG. 5 (A), and FIG. 5 (D) is a VD-VD cross-sectional view of the vehicular illumination device of FIG. 5 (A). 6A is an enlarged partial cross-sectional view showing an essential part of the vehicular lighting device shown in FIG. 5C, and FIG. 6B is an alternate long and short dash line VIB in the cross-sectional view of FIG. FIG. 6C is an enlarged partial cross-sectional view showing the vicinity of the range surrounded by a circle, and FIG. 6C is an enlarged view showing the vicinity of the range surrounded by the alternate long and short dash line VIC in the cross-sectional view of FIG. FIG. 6D is an enlarged partial cross-sectional view showing a modification of the configuration shown in FIG. 6C. 7A and 7B are diagrams showing a conventional electronic device. FIG. 7A is a perspective view, FIG. 7B is a plan view, and FIG. 7C is a VIIC-VIIC of the electronic device in FIG. FIG. 7D is a cross-sectional view of the electronic device of FIG.

  Hereinafter, a vehicular lighting device 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a vehicular illumination device 1 according to an embodiment of the present invention, FIG. 2 is a perspective view of the vehicular illumination device 1 according to an embodiment, and FIG. 3 is the vehicular illumination device of FIG. It is the perspective view which looked at the illuminating device 1 from the back side. The vehicle lighting device 1 illustrated in these drawings is a lamp installed on a ceiling portion of a passenger compartment. For example, the vehicular lighting device 1 may be installed on a ceiling portion hidden by a sun visor when a sun visor that can be rotated between the use position and the storage position is in the storage position. The lighting and extinguishing operations of the vehicular illumination device 1 may be performed in conjunction with the rotation between the storage position of the sun visor and the use position, and the lid of the vanity mirror provided in the sun visor is opened and closed. It may be performed in conjunction with the device, or may be performed by a separate switch, and is not limited to these.

As illustrated, the vehicular lighting device 1 includes a lens unit 10, a housing 20, a substrate 30, and a cover 40.
(Lens part)
The lens unit 10 is a plate-like member mainly made of a light-transmitting resin such as polycarbonate resin (PC resin) or acrylic resin (PMMA resin). A light diffusing material may be dispersed in the lens unit 10. A portion including the center of the lens portion 10 is configured such that the inner structure cannot be seen through by performing uneven processing such as embossing or lens cutting on the surface.

(substrate)
The substrate 30 is realized by a so-called printed wiring board, and particularly realized by a metal base substrate having excellent heat dissipation such as an aluminum substrate or a copper substrate. An LED 31 as a light source and other elements are mounted on the surface of the substrate 30. Further, the board 30 is provided with a connector fitting portion 32, and a power supply terminal for supplying power to the LED 31 is accommodated in the connector fitting portion 32. The connector fitting portion 32 has a connector receiving opening 32a for receiving a power supply connector. The LED 31 is packaged including a light emitting unit. When power is supplied via a power supply terminal and circuit wiring (not shown) of the substrate 30, the light emitting unit emits light. The outer shape of the packaged LED 31 is arbitrary, such as a rectangular shape, a circular shape, or a bullet shape.

(housing)
The housing 20 is made of a resin such as polypropylene resin (PP resin), polybutylene terephthalate resin (PBT resin), polycarbonate resin (PC resin), ABS resin, PC resin + ABS resin, and reflects light from the LED 31 toward the lens unit 10 side. A reflecting portion 21 having a reflecting surface 21a for receiving the substrate 30 and a substrate receiving portion 22 for receiving and storing the substrate 30. 4A is a view of the housing 20 viewed from the reflecting portion 21 side, and FIG. 4B is a view of the housing 20 viewed from the substrate housing portion 22 side. The reflecting portion 21 has a plurality of reflecting surfaces 21a on the inside, and these reflecting surfaces 21a form a substantially quadrangular pyramid shape, and the inner side surface 21b (this surface 21b also functions as a reflecting surface). And an opening 21c (hereinafter referred to as “LED insertion opening 21c”). The LED insertion opening 21 c is provided at a position corresponding to the LED 31. That is, when the board | substrate 30 is accommodated in the board | substrate accommodating part 22, LED31 will be a position which penetrates LED insertion opening 21c.

  In the reflecting portion 21, the entire surface on the side facing the inner back surface 21b is a substantially rectangular opening (hereinafter referred to as “light emitting opening 21d”), and demarcates the edge of the light emitting opening 21d. The edge portion of the housing 20 can be engaged with the back side of the edge portion of the lens unit 10. In addition, it is preferable to set the reflective surface 21a to a highly reflective material, color, or the like. For example, the reflective surface 21a may be white by making the entire housing 20 white, or only the reflective surface 21a may be selectively white.

  The substrate housing portion 22 is integrally formed on the side opposite to the reflecting surface 21a and the inner back surface 21b of the reflecting portion 21 (that is, the outer surface of the reflecting portion 21), and at least of the inner back surface 21b. Enclose the opposite surface and its vicinity. A part of the housing 20 belongs to both the reflection portion 21 and the substrate storage portion 22. The external shape of the board | substrate storage part 22 has a shape which follows a rectangular parallelepiped shape as a whole. The substrate storage portion 22 has a substrate receiving opening 22 a for receiving the substrate 30 on the side opposite to the reflecting portion 21. A plurality of substrate support portions 22 b are provided in the substrate storage portion 22, and a surface of the substrate 30 on which the LED 31 is mounted (hereinafter referred to as “element mounting surface”) is brought into contact with the substrate support portion 22 b to The substrate 30 can be stored in the substrate storage portion 22 in such a manner that a surface opposite to the mounting surface (hereinafter referred to as “element non-mounting surface”) is exposed to the outside of the substrate receiving opening 22a. The surface opposite to the inner surface 21b of the reflection portion 21 is also included in the substrate support portion 22b. Further, the board housing part 22 has a connector insertion opening 22c for inserting a connector at a position corresponding to the connector receiving opening 32a of the connector fitting part 32 when the board 30 is housed. The board receiving opening 22a and the connector insertion opening 22c are respectively provided on two adjacent surfaces of the board housing portion 2.

  A snap fit 23 for attaching the vehicle lighting device 1 to the ceiling is formed on the outer surface of the housing 20 by engaging with the edge of the engagement opening of the interior material of the vehicle ceiling. The snap fit 23 is formed to have a mountain shape protruding in the direction of the back side of the ceiling interior material when mounted on the ceiling. The snap fit 23 is formed with a skirt that protrudes outward from the edge of the lens unit 10, and the skirt is locked to the edge of the engagement opening of the interior material.

(Cover 40)
5A is a plan view of the back side of the vehicular lighting device 1, and FIG. 5B is a VB-VB cross-sectional view of the vehicular lighting device 1 of FIG. 5A, and FIG. FIG. 5A is a sectional view taken along the line VC-VC of the vehicle lighting device 1 in FIG. 5A, and FIG. 5D is a sectional view taken along the line VD-VD of the vehicle lighting device 1 in FIG. 6A is an enlarged partial cross-sectional view showing an enlarged main part (the vicinity of the cover 40) of the vehicular lighting device 1 shown in FIG. 5C, and FIG. 6B is FIG. 6A. FIG. 6C is an enlarged partial cross-sectional view showing the vicinity of the range surrounded by the alternate long and short dash line VIB in FIG. 6C, and FIG. 6C is a cross-sectional view of FIG. It is an enlarged partial sectional view expanding and showing.

  The cover 40 is made of a metal such as aluminum, iron or copper, an inorganic material such as aluminum nitride, a resin containing metal or carbon, and has a shape obtained by bending a single plate. More specifically, as shown in FIG. 1, the cover 40 has a substantially rectangular heat receiving portion 41 that faces the substrate receiving opening 22 a of the substrate storing portion 22 and covers it. The cover 40 has two flat side-extending portions 42 and 43 that are in contact with the two sides of the heat receiving portion 41 and are bent about 90 degrees from the heat receiving portion 41 to the same side. There is no laterally extending portion at the portion of the portion 41 that contacts the remaining two sides. Thus, when the cover 40 is attached to the substrate storage part 22, the two side surfaces that are in contact with the surface having the board receiving opening 22a and the surface having the connector insertion opening 22c of the substrate storage part 22 are located on the two sides of the cover 40. The connector insertion opening 22 c is not covered by the cover 40 while being covered by the extending portions 42 and 43. The cover 40 may have another side extending portion at a position covering the surface of the board housing portion 22 opposite to the connector insertion opening 22c.

  The heat receiving portion 41 has a closed loop-shaped protruding portion 41 a that protrudes inside the cover 40. The two laterally extending portions 42 and 43 have a function as a fixed portion that is fixed to the substrate storage portion 22. That is, a plurality of engagement holes 42 a and 43 a are formed in the laterally extending portions 42 and 43 as fixed portions, respectively, and when the cover 40 is attached to the substrate storage portion 22, the substrate of the substrate storage portion 22 is formed. The receiving openings 22a and the connector insertion openings 22c are respectively engaged with a plurality of engaging protrusions 22d formed on the outer sides of the two opposing side faces that are in contact with the two faces. At that time, the protrusion 41 a of the heat receiving portion 41 of the cover 40 abuts on the element non-mounting surface of the substrate 30 on the entire circumference, and the element mounting surface of the substrate 30 abuts on the substrate support portion 22 b of the housing 20. As a result, the substrate 30 is sandwiched and held between the protrusion 41 a of the heat receiving portion 41 and the substrate support portion 22 b of the housing 20. The dimensions of each part are determined so that the heat receiving part 41 of the cover 40 does not directly contact the housing 20.

  The cover 40 has a function of protecting the substrate 30 stored in the substrate storage unit 22, a function as a heat sink that receives heat from the substrate 30 by contacting the substrate 30, and a radiator that dissipates the received heat to the outside. It has the function of. In particular, in addition to the heat receiving portion 41 that receives heat by directly contacting the element non-mounting surface of the substrate 30 and releases the heat to the outside, it has two laterally extending portions 42 and 43 that further spread from the heat receiving portion 41. Therefore, a large area for receiving and radiating heat is secured. Thereby, the cover 40 can provide sufficient heat receiving and heat dissipation effects.

  Further, with the above-described configuration, a closed space is formed by the protrusion 41a between the heat receiving portion 41 of the cover 40 and the element non-mounting surface of the substrate 30. The closed space is filled with heat transfer grease 50 as shown in FIG. Thus, the protruding portion 41a constitutes a grease pool. The heat transfer grease 50 is used to increase the heat transfer from the substrate 30 to the cover 40, thereby increasing the effect of the cover 40 receiving and radiating the heat generated by the LEDs 31. For example, a silicone-based heat transfer grease is used as the heat transfer grease 50. As the heat transfer grease 50, a two-component curable resin is preferably used. Thereby, the heat transfer grease 50 is hardened with the passage of a predetermined time, and the possibility that the heat transfer grease 50 leaks from the gap between the protrusion 41a and the non-element mounting surface can be reduced.

  As shown in FIG. 6C, the engaging protrusion 22d provided on the side surface of the substrate housing portion 22 of the housing 20 has an inclined portion 221d on the side opposite to the substrate receiving opening 22a. It has an inclination which approaches the board | substrate reception opening 22a, so that it goes to the outer side (namely, the side away from the side surface of the board | substrate storage part 22 and left side in FIG.6 (C)). On the other hand, the positions of the engagement holes 42a and 43a of the cover 40 are such that the edges of the engagement holes 42a and 43a are always in contact with the inclined portion 221d, and the edges of the engagement holes 42a and 43a and the inclined portion 221d exert a pressing force. It is set to be a position. Since the inclined portion 221d has the inclination as described above, the force exerted by the inclined portion 221d on the edges of the engaging holes 42a and 43a opens the side extending portions 42 and 43 of the cover 40 outward. A component to be pressed, and a component that acts to pull the heat receiving portion 41 of the cover 40 against the element non-mounting surface of the substrate 30 by pulling the side extending portions 42 and 43 in the vertical direction (vertical direction in FIG. 6C). Can be broken down into

  As described above, the heat receiving portion 41 of the cover 40 is in contact with the element non-mounting surface of the substrate 30, but the dimensions of each portion are determined so as not to contact the housing 20. Further, as described above, the force exerted by the inclined portion 221d on the edges of the engagement holes 42a and 43a of the cover 40 pulls the side extending portions 42 and 43 of the cover 40 in the vertical direction, and the heat receiving portion 41 of the cover 40 is placed on the substrate. 30 includes a component that acts to press against the element non-mounting surface, and the inclined portion 221d always presses the edges of the engagement holes 42a and 43a, so that the heat receiving portion 41 of the cover 40 is always the element of the substrate 30. It will be pressed against the non-mounting surface. As a result, a pressing force always acts between the protrusion 41a and the element non-mounting surface, and both come into close contact with each other. Therefore, the possibility that the grease 50 leaks to the outside from the gap between the protrusion 41a and the element non-mounting surface is further reduced. In particular, if the cover 40 floats in the vertical direction due to variations in the shape and position of the housing 20, the substrate 30, and the cover 40, abnormal noise and grease leakage may occur, but as described above, the protrusion 41 a and the element non-mounting surface Since the pressing force always works during the period of time and they are in close contact with each other, the possibility of abnormal noise and grease leakage due to the rising of the cover 40 can be effectively reduced.

  In the engaging protrusion 22d, a flat portion 222d is provided on the outer side of the inclined portion 221d. The flat portion 222d does not have an inclination like the inclined portion 221d, and has a surface perpendicular to the side surface of the substrate storage portion 23. Therefore, for some reason, the edges of the engagement holes 42a, 43a move on the inclined portion 221d, and the side extending portions 42, 43 as the fixed portions of the cover 40 are elastically deformed so as to open further outward. In addition, the edges of the engagement holes 42a and 43a are caught by the flat portion 222d, and the side extending portions 42 and 43 as the fixed portions of the cover 40 can be prevented from further opening. Note that although the inclined portion 221d shown in FIG. 6C has a flat inclined surface, the inclined surface is a curved surface like the inclined portion 221d ′ shown in FIG. 6D. It may be.

  In the vehicle lighting device 1 described above, when the LED 31 emits light upon receiving electric power, the direct light from the LED 31 and the light reflected by the reflection surface 21a and the inner surface 21b are transmitted from the light emission opening 21d to the lens unit. 10 is irradiated to the exterior of the vehicular lighting device 1, that is, the vehicle interior. As understood from FIG. 4, the installation position of the LED 31 is slightly shifted to one side with respect to the center of the planar shape of the vehicle lighting device 1, and the reflection surface 21 a of the reflection portion 21 also corresponds to the installation position of the LED 31. It has a different shape. This is for matching the irradiation range of the light emitted from the vehicular lighting device 1 with the intended irradiation range.

In the configuration described above, the heat receiving portion 41 preferably covers the entire element non-mounting surface of the substrate 30, but may cover only a part.
Further, in the configuration described above, each of the side extending portions 42 and 43 preferably covers the entire corresponding surface of the side surfaces of the substrate storage portion 22, but covers only a part thereof. May be. Alternatively, each of the laterally extending portions 42 and 43 may extend to a wider range than the corresponding surface of the side surfaces of the substrate storage portion 22.
In the above description, the laterally extending portions 42 and 43 have been described as flat plate portions, but the present invention is not limited to this, and may have any shape such as a strip shape, a rod shape, or a lattice shape. For this reason, the laterally extending portions 42 and 43 as the fixed portions are also formed, for example, as portions extending in a belt shape from the heat receiving portion 41, and the engagement holes 42a and 43a are formed therein to engage with the protrusions 22d. You may let them.
Further, the method of fixing the laterally extending portions 42 and 43 as the fixed portions to the side surface of the substrate housing portion 22 is not limited to the above-described engagement, but is also based on a fixing method such as screwing or adhesion. It is good.

1 ... Vehicle lighting device (electronic equipment)
DESCRIPTION OF SYMBOLS 10 ... Lens part 20 ... Housing 21 ... Reflection part 22 ... Board | substrate storage part (storage part)
23 ... Snap fit 30 ... Substrate 31 ... LED (element)
32 ... Connector fitting part 40 ... Cover (heat radiation part)
41 ... heat receiving part 42, 43 ... side extension part (fixed part)

Claims (8)

An electronic device having an element that generates heat,
A substrate on which the element is mounted;
A storage portion for storing the substrate by exposing an element non-mounting surface of the substrate;
A heat dissipating part,
The heat radiating portion has a fixed portion fixed to a side surface of the storage portion, and a heat receiving portion having a surface facing the element non-mounting surface so as to cover the element non-mounting surface,
The heat receiving unit has an accumulation of grease.   The electronic device according to claim 1, wherein the grease pool has a closed loop-shaped protrusion.   The electronic device according to claim 1, wherein the fixed portion is fixed so as to press the heat receiving portion against the element non-mounting surface. The side surface of the storage portion has a protrusion,
The electronic device according to claim 1, wherein the fixed portion includes a hole that engages with the protrusion.   The electronic device according to claim 1, wherein the heat receiving unit and the storage unit form a case.   The electronic device according to any one of claims 1 to 5, wherein the heat dissipating part is a single plate-like member.   The electronic device according to claim 1, wherein the fixed portion has a shape along the side surface of the storage portion. The storage portion has a rectangular parallelepiped shape,
The electronic device according to claim 1, wherein the heat radiating unit covers one surface of the rectangular parallelepiped shape of the storage unit and two or three surfaces adjacent to the one surface. .

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