JP2007329338A - Heat dissipation structure in electronic instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipation structure in an electronic instrument that can be applied to a heating element which is mounted on a printed board, and in which a projection is formed in a part of a face on a side which is brought into contact with a heat sink and to a plurality of heating elements different in height. <P>SOLUTION: In the heat dissipation structure in the electronic instrument radiating heat of the heating element 12 mounted on the printed board 11 through the heat sink 13, the projection 12b is formed in a part of the face 12a on the side which is brought into contact with the heat sink. In the heat sink, a face 13b confronted with the projection of the heating element is brought into contact with the projection of the heating element, and projections 13d which are brought into contact with a region 12d are formed in a region 13c confronted with the region 12d except for the projection. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat dissipation structure in an electronic device that efficiently transfers heat of a heat generating element mounted on a printed circuit board to a heat sink to dissipate the heat.

  Electronic components such as an IC element (CPU) and a large-scale integrated circuit for control (LSI) mounted on a printed circuit board of an electronic device have a structure in which a chip is enclosed in a ceramic or resin package. These IC elements and control large-scale integrated circuits are heating elements, and it is necessary to secure a heat dissipation path. As a heat radiating structure of the heat generating element, a structure is proposed in which heat can be radiated even when the heat generating portions are not limited to the central portion but scattered over a wide range (see, for example, Patent Document 1). In this heat dissipation structure, a heat sink in which a bonding seat protrudes from a part of the bottom surface is bonded to the center of the top surface of the heating element package at the bonding seat portion, and the bottom surface of the heat sink other than the bonding seat and the top surface of the heating element package The heat conductive rubber sheet is interposed in the gap.

Alternatively, as shown in FIG. 10, the heat sink 5 and the upper surfaces 2a, 3a of the heat generating elements 2, 3, 4 that integrally cover a plurality of heat generating elements 2, 3, 4 mounted on the upper surface 1a of the printed board 1 are integrated. , 4a, and a structure in which a heat conductive sheet 6 is interposed between the heat generating elements 2 to 4 to transmit heat to the heat sink 5 to dissipate heat.
JP-A-8-222667 (page 2-3, FIG. 1)

  However, the heat sink disclosed in Patent Document 1 is applied to a heating element having a planar structure on the top surface of the package, and cannot be applied to a heating element having a structure in which a protrusion is formed on the top surface of the package. . In particular, when a plurality of heat generating elements are arranged in one package, the shape of the upper surface of the component including the heat generating element varies depending on the product (manufacturer) and may not be uniform (planar). For this reason, the shape of the heat sink itself has to be changed, which takes time and cost.

  In addition, it is necessary to manage the thickness of the thermally conductive rubber sheet in order to adhere the adhesive seat to the upper surface of the package by pressing the thermally conductive rubber sheet on the bottom surface other than the adhesive seat of the heat sink. That is, even when the thickness of the thermally conductive rubber sheet is slightly larger than the predetermined thickness, the heat sink adhesive seat cannot be satisfactorily adhered to the entire upper surface of the package and may be peeled off. Further, when the plate thickness of the heat conductive rubber sheet is thinner than a predetermined plate thickness, the heat conduction is poor.

  Further, the heat conductive rubber sheet 6 shown in FIG. 10 has a thickness corresponding to the gap between the heat generating element 2 and the heat sink 5 having the lowest height from the upper surface 1 a of the printed board 1. For this reason, the clearance gap between the heat generating elements 3 and 4 higher than the heat generating element 2 and the heat sink 5 becomes narrow. A large reaction force is generated in the heat sink 5 due to the elasticity of the thickness of the heat conductive rubber sheet 6 in the narrow space portion, and it swells at the center as shown in the figure.

  For this reason, there is a possibility that a gap is generated in the bulging portion and the heat conduction efficiency is lowered or the heat sink 5 is deformed. In particular, when the heat sink 5 is a low-strength plate such as an aluminum plate, it is easily deformed. In addition, it is unclear whether the bulging portion is in close contact with the heat conductive rubber sheet 6, and it cannot be confirmed whether the heat is sufficiently transmitted from each of the heating elements 2 to 4 to the heat sink 5. Furthermore, an excessive stress may be applied to the high heating elements 3 and 4 due to the reaction force caused by the elasticity of the heat conductive rubber sheet 6.

  An object of the present invention is an electronic device that can be applied to a heating element in which a protrusion is formed on a part of a surface mounted on a printed circuit board and in contact with a heat sink, or a plurality of heating elements having different heights. It is in providing the heat dissipation structure in.

  In order to solve the above-described problem, a heat dissipation structure for an electronic device according to the present invention is a heat dissipation structure in an electronic device that dissipates heat of a heat generating element mounted on a printed circuit board via a heat sink. A protrusion is formed on a part of the surface in contact with the heat sink, and the surface of the heat sink that faces the protrusion of the heat generating element is in contact with the protrusion of the heat generating element and in a region that faces a region other than the protrusion. A protrusion that contacts the region is formed.

  The upper surface of the protrusion of the heat generating element mounted on the printed circuit board is brought into contact with the opposite surface (lower surface) of the heat sink, and the lower surface of the protrusion of the heat sink is brought into contact with the surface (upper surface) of the region other than the protrusion of the heat generating element. Thereby, the heat generating element in which the protrusion is formed can be brought into good contact with the heat sink, and the heat of the heat generating element can be efficiently transmitted to the heat sink. As a result, the heat of the heating element can be radiated favorably.

  The heat dissipation structure for an electronic device according to claim 2 of the present invention is a heat dissipation structure in an electronic device that dissipates heat of a heat generating element mounted on a printed circuit board via a heat sink, and the heat generating element is in contact with the heat sink. A protrusion is formed on a part of the side surface, the heat sink is opposed to a region other than the protrusion of the heat generating element, and a protrusion having the same height as or lower than the protrusion is formed. A heat conductive grease is interposed between the heat sink and the surface of the heat generating element that is in contact with the heat sink.

  The upper surface of the protrusion of the heating element mounted on the printed circuit board is opposed to the surface (lower surface) facing the heat sink with a slight gap, and the lower surface of the protrusion of the heat sink is the surface of the region other than the protrusion of the heating element. Opposite the top surface with a slight gap. Then, thermally conductive grease is interposed (filled) between the heating element and the heat sink. Since the gap between the upper surface of the projecting portion of the heat generating element and the surface of the region other than the projecting portion and the lower surface of the projecting portion of the heat sink is narrow, the heat of the heat generating element is well transmitted to the projecting portion through the heat conductive grease.

  Further, the height of the protrusion of the heat sink is slightly lower than the height of the protrusion of the heat generating element so that the upper surface of the protrusion of the heat generating element is in direct contact with the surface of the heat sink and the lower surface of the protrusion of the heat sink and the heat generating element Thermally conductive grease is interposed (filled) in a gap with the region other than the protruding portion on the upper surface of the substrate. Thereby, the heat of the heat generating element in which the protruding portion is formed can be efficiently transmitted to the heat sink. As a result, the heat of the heating element can be radiated favorably.

  According to a third aspect of the present invention, there is provided a heat dissipating structure for an electronic device, wherein the heat generating element in the electronic device dissipates the heat of the heat generating element mounted on the printed circuit board through the heat sink, and the heat generating element contacts the heat sink. A protrusion is formed on a part of the side surface, a heat conductive sheet is interposed between the heat generating element and the heat sink, and the heat sink is disposed in a region facing the protrusion of the heat generating element. A hole for allowing the part to escape is formed, and a protrusion for contacting the thermally conductive sheet is formed in a region other than the protrusion of the heating element.

  A heat conductive sheet is interposed between the heat generating element mounted on the printed circuit board and the heat sink. A part (excess part) of the heat conductive sheet interposed between the upper surface of the protrusion of the heating element and the heat sink protrudes out of the hole, so that the protrusion and the heat sink are in good contact.

  Further, the heat conductive sheet is brought into contact with a region other than the protruding portion on the upper surface of the heat generating element by the protrusion of the heat sink, and a part (excessive portion) thereof protrudes to the side, so that the heat sink is in good contact. Thereby, the heat of the heat generating element in which the protrusion is formed can be efficiently transmitted to the heat sink, and the heat of the heat generating element can be radiated well.

  According to a fourth aspect of the present invention, there is provided a heat dissipation structure for an electronic device, wherein a heat conductive sheet is interposed between a plurality of heat generating elements mounted on a printed circuit board and different heat sinks, and the heat generating elements. In the heat dissipating structure in the electronic device for transferring heat to the heat sink to dissipate heat, the heat sink is formed with a hole for allowing a part of the heat conductive sheet to escape in a region facing the heat generating element. The heat conductive sheet is contacted substantially uniformly.

  A heat conductive sheet is integrally mounted on a plurality of heating elements having different heights mounted on a printed board, and a heat sink is attached. The heat sink exposes a part (excess part) of the heat conductive sheet out of the hole in a region where the reaction force due to the elastic force of the heat conductive sheet is large, that is, a heating element having a high height from the printed board. Thereby, while reducing the reaction force with respect to the heat sink by the elasticity of a heat conductive sheet, reaction force is equalized. Moreover, the stress by the heat conductive sheet added to the several heat generating element from which height differs is reduced.

  According to the present invention, it is possible to efficiently transfer the heat of the heating element having a shape in which the protruding portion is formed on a part of the surface in contact with the heat sink to the heat sink, thereby improving the heat dissipation efficiency. Further, it is possible to interpose a heat conductive grease, a heat conductive sheet, or the like between the heat generating element having a shape in which a protruding portion is formed on a part of the surface in contact with the heat sink and the heat sink.

  In addition, the state of the heat conductive sheet can be visually confirmed from the hole for letting out the heat conductive sheet of the heat sink, so that it is possible to confirm a mounting error at the time of manufacture. In this case, it can be confirmed that the heat conductive sheet is in close contact with the heat sink. Moreover, when a part (excess part) of a heat conductive sheet protrudes from the hole of a heat sink, a heat conductive sheet can be stuck to a heat sink. In addition, when a heat conductive sheet is interposed, it is not necessary to accurately manage the plate thickness, so that management of components is not necessary and the assembling property is improved.

  Furthermore, a heat conductive sheet can be reasonably interposed between a plurality of heat generating elements mounted on a printed circuit board and different heights, and the heat of each heat generating element can be transmitted to the heat sink well. I can do it. In this case, the elasticity due to the thickness of the heat conductive sheet can be reduced, and the reaction force to the heat sink can be greatly reduced. Further, the reaction force against the heat sink can be made uniform. Further, it is possible to reduce the deformation applied to the heat sink and the stress applied to the heating element.

  Hereinafter, a heat dissipation structure in the electronic apparatus according to the first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a heating element 12 such as an IC element is mounted at a predetermined position, for example, a substantially central position on the upper surface 11 a of the printed board 11. Further, a heat sink fixing portion 11b for fixing the heat sink 13 protrudes on one side of the upper surface 11a, and a screw hole 11c is formed on the upper surface. A large number of non-heat generating electronic components (not shown) are mounted around the heat generating element 12 on the upper surface 11a of the printed circuit board 11, but these electronic components are omitted.

  The heating element 12 has a rectangular parallelepiped shape, and a protruding portion 12b is formed at, for example, a central position of the upper surface 12a. The protrusion 12b protrudes from the upper surface 12a in a substantially rectangular parallelepiped shape. The heat generating elements 12 are arranged such that the heat generating portions are scattered over a wide range of, for example, the upper surface 12c of the protruding portion 12b and the region 12d around the protruding portion 12b.

  The heat sink 13 has a flat plate shape substantially the same size as the printed circuit board 11, and as shown in FIG. 2, the region 13b facing the upper surface 12c of the substantially central position of the lower surface 13a, that is, the protruding portion 12b of the heating element 12, is the protruding portion 12a. It is considered as a contact surface. On the lower surface 13a, a large number of protrusions 13d are formed in a region 13c facing the region 12d around the region 13b and around the protrusion 12b with a slight gap. These protrusions 13 d have a lower surface 13 e that is flat and set to the same height as the protrusions 12 b of the heat generating element 12. Further, the height of the heat sink fixing portion 11b of the printed circuit board 11 shown in FIG. 1 is set to the same height as the height from the upper surface 11a of the printed circuit board 11 to the upper surface 12c of the protruding portion 12b of the heating element 12.

  As shown in FIG. 1, a mounting hole 13 f is formed on one side of the heat sink 13 corresponding to the screw hole 11 c of the heat sink fixing portion 11 b of the printed board 11. The heat sink 13 is formed by pressing a lightweight and inexpensive metal plate, such as an aluminum plate, with good thermal conductivity.

  Further, as described above, a large number of non-heat generating electronic components (not shown) are mounted around the heat generating element 12 on the printed circuit board 11, and the height of these electronic components is the protruding portion 12 b of the heat generating element 12. Some are higher than Therefore, the heat sink 13 is formed with a hole, a notch, or the like (not shown) at a position facing such an electronic component so as not to interfere.

  As shown in FIG. 1, the heat sink 13 is disposed on the heat generating element 12 mounted on the printed board 11, and one side portion is placed on the heat sink fixing portion 11b. And the heat sink 13 is fixed to the heat sink fixing | fixed part 11b through the attachment hole 13f with the screw 14 screwed together in the screw hole 11c. In this state, as shown in FIG. 3, the central region 13 b of the lower surface 13 a of the heat sink 13 contacts (contacts) the upper surface 12 c of the protruding portion 12 b of the heating element 12. Then, the lower surface 13e of each protrusion 13d formed so as to protrude downward outside the region 13b comes into contact (contact) with the region 12d around the protrusion 12b of the heating element 12.

  As a result, the heat generating portion scattered in the upper surface 12c of the protruding portion 12b and the surrounding region 12d of the heat generating element 12 having the protruding portion 12b on the upper surface 12a can be brought into contact with the heat sink 13. As a result, the heat of the heating element 12 can be efficiently transmitted to the heat sink 13. Since the heat sink 13 is substantially the same size as the printed board 11, the heat sink 13 has a large surface area and can dissipate heat transferred from the heating element 12 satisfactorily.

  FIG. 4 is a cross-sectional view of a heat dissipation structure in an electronic apparatus according to the second embodiment of the present invention. The same or corresponding members as those shown in FIG. 1 are denoted by the same or corresponding reference numerals, and detailed description thereof will be omitted. As shown in FIG. 4, the heat sink 13 is formed such that the height of each protrusion 13 d ′ is the same as or slightly lower than the height from the upper surface 12 a of the protrusion 12 b of the heating element 12.

  When the height of the protrusion 13d ′ of the heat sink 13 is slightly lower than the height of the protrusion 12b of the heat generating element 12, the upper surface 12c of the protrusion 12b of the heat generating element 12 is brought into contact with the region 13b of the lower surface 13a of the heat sink 13. Then, the lower surface 13e ′ of the protrusion 13d ′ can be opposed to the region 12d of the upper surface 12a of the heating element 12 with a slight gap.

  A heat conductive grease 15 is interposed (filled) between the heat generating element 12 and the lower surface 13 a of the heat sink 13. That is, the regions 13b and 13c of the lower surface 13a of the heat sink 13 facing the upper surface 12c of the protruding portion 12b of the heat generating element 12 and the region 12d around the protruding portion 12b, the region 12d, and the lower surface 13e ′ of each protruding portion 13d ′. In between, the heat conductive grease 15 is filled. An example of the thermally conductive grease is silicone grease.

  The height of the protrusion 13d 'of the heat sink 13 is slightly lower than the height of the protrusion 12b of the heat generating element 12, and the upper surface 12c of the protrusion 12b is brought into direct contact with the region 13b of the lower surface 13a of the heat sink 13. Also good. In this case, a slight gap is formed between the lower surface 13 e ′ of the protrusion 13 d ′ of the heat sink 13 and the region 12 d facing the heat generating element 12. Then, the heat conductive grease 15 may be interposed (filled) between the region 12 d other than the protruding portion 12 b of the upper surface 12 a of the heat generating element 12 and the lower surface 13 a of the heat sink 13.

  Heat from the upper surface 12c of the protruding portion 12b of the heat generating element 12 is efficiently transmitted to the lower surface 13a of the heat sink 13 through the thermally conductive grease 15 filled at a slight interval. Further, the heat in the region 12 d of the upper surface 12 a of the heating element 12 is transmitted to the lower surface 13 a of the heat sink 13 through the heat conductive grease 15. Further, the lower surface 13e ′ of the protrusion 13d ′ of the heat sink 13 is opposed to the region 12d of the upper surface 12a of the heat generating element 12 with a slight gap, so that the heat of the region 12d is filled with the slight gap. It is efficiently transmitted to the protrusion 13d ′ via the conductive grease 15.

  Further, when the upper surface 12c of the protruding portion 12b of the heat generating element 12 is brought into direct contact with the lower surface 13a of the heat sink 13, heat from the upper surface 12c of the protruding portion 12b of the heat generating element 12 is directly transmitted to the heat sink 13 and a good heat dissipation effect. Is obtained. The lower surface 13e ′ of the protrusion 13d ′ of the heat sink 13 is opposed to the region 12d of the upper surface 12a of the heat generating element 12 with a slight space therebetween, so that the heat of the region 12d is filled with the small space. It is efficiently transmitted to the protrusion 13d ′ via the conductive grease 15. Thereby, the heat of the heat generating element 12 can be transmitted to the heat sink 13 favorably, and a good heat dissipation effect can be obtained.

  In this structure, the height of the protrusion 13d 'of the heat sink 13 from the lower surface 13e' need not be exactly the same as the height of the protrusion 12b from the upper surface 12a of the heating element 12. For this reason, the height accuracy of the protrusion 13d 'in the press working can be lowered, and the manufacture of the heat sink 13 is facilitated without requiring a strict dimensional tolerance.

  5 to 8 show a heat dissipation structure in an electronic apparatus according to the third embodiment of the present invention. The same or corresponding members as those shown in FIGS. 1 and 4 are denoted by the same or corresponding reference numerals, and detailed description thereof is omitted. As shown in FIG. 5, a heat conductive sheet 17 is interposed between the upper surface 12 a of the heating element 12 and the upper surface 12 c of the protruding portion 12 b and the lower surface of the heat sink 13. An example of the thermally conductive sheet is a silicon rubber sheet reinforced with glass cloth or the like.

  As shown in FIGS. 5 and 6, the heat sink 13 has a plurality of holes 13 g formed in a region 13 c facing the upper surface 12 c of the protruding portion 12 b of the heating element 12. These holes 13g are for releasing a part (excessive part) of the heat conductive sheet 17 in the region of the protruding portion 12b of the heating element 12. The heat sink 13 has a large number of protrusions 13d 'in the region 13c of the lower surface 13a. The height of these protrusions 13d 'is slightly lower than the height from the upper surface 12a of the protrusion 12b of the heating element 12. The gap between the lower surface 13 e ′ of the protrusion 13 d ′ and the region 12 d of the upper surface 12 a of the heating element 12 is slightly narrower than the thickness of the heat conductive sheet 17.

  Then, as shown in FIG. 5, a heat conductive sheet 17 is placed on the heating element 12, and then a heat sink 13 is arranged and fixed with screws 14 as in the case of FIG. 1. Thereby, the heat conductive sheet 17 is pressed against the heat generating element 12 by the heat sink 13. As shown in FIGS. 7 and 8, a part (excess part) of the heat conductive sheet 17 pressed against the upper surface 12c of the protruding part 12b protrudes (escapes) from each hole 13g.

  Further, a part (excess part) of the heat conductive sheet 17 pressed against the region 12d of the upper surface 12a of the heat generating element 12 by the lower surface 13e 'of the protrusion 13d' of the heat sink 13 protrudes to the side. As a result, the pressing force (stress) on the heat generating element 12 by the heat conductive sheet 17 is reduced, and the heat conductive sheet 17 and the heat sink 13 or the heat conductive sheet 17 and the heat generating element 12 are closely adhered to each other. The gap is not generated.

  The heat of the upper surface 12 c of the protruding portion 12 b of the heat generating element 12 and the region 12 d around the protruding portion 12 b is transmitted to the lower surface 13 a of the heat sink 13 through the heat conductive sheet 17. The lower surface 13e ′ of the protrusion 13d ′ of the heat sink 13 is opposed to the region 12d of the upper surface 12a of the heat generating element 12 with a slight gap so that the heat generated in the region 12d protrudes through the heat conductive sheet 17. It is efficiently transmitted to the part 13d ′. Thereby, the heat of the heat generating element 12 can be favorably transmitted to the heat sink 13 and a good heat dissipation effect can be obtained.

  Then, an excessive portion of the heat conductive sheet 17 is brought out from the hole 13g in the region facing the protruding portion 12b of the heat generating element 12 where the reaction force due to the elasticity of the heat conductive sheet 17 is large, thereby reducing the reaction force against the heat sink 13. And uniform reaction force. In addition, the stress applied to the heating element 12 can be reduced.

  Moreover, the state of the heat conductive sheet 17 can be visually recognized from the hole 13g of the heat sink 13, and the attachment mistake etc. at the time of manufacture can be confirmed. It can also be confirmed that the heat conductive sheet 17 is in close contact with the lower surface 13 a of the heat sink 13. Furthermore, the heat conductive sheet 17 can stick to the lower surface 13 a of the heat sink 13 by protruding the heat conductive sheet 17 from the hole 13 g of the heat sink 13.

  The hole 13g may be a single hole having a size substantially corresponding to the protruding portion 12b without being formed from a plurality of holes.

  FIG. 9 is a sectional view of a heat dissipation structure in an electronic device according to the fourth embodiment of the present invention. A plurality of heating elements 22, 23, and 24 having different heights are mounted on the upper surface 21 a of the printed circuit board 21. These heating elements 22, 23 and 24 have upper surfaces 22a, 23a and 24a as heating portions. A heat sink 25 is attached on the printed circuit board 21, and a heat conductive sheet 27 is interposed between the upper surfaces 22 a, 23 a, 24 a of the heat generating elements 22, 23, 24 and the heat sink 25.

  The heat sink 25 is formed such that both side portions 25a are bent downward at a right angle, and a plurality of locking claws 25b are bent at the lower end portion. The height of both side portions 25a is set to be slightly higher than, for example, the height of the heat generating element 23, which is the highest of the heat generating elements 22, 23, and 24. In the heat sink 25, the locking claws 25 b on both side portions 25 a can be locked to the locking portions 21 b formed on the side surfaces of the printed circuit board 21.

  The heat sink 25 has holes 25e, 25f, and 25g formed in regions (positions) facing the heat generating elements 22, 23, and 24 of the upper plate portion 25c. The holes 25e, 25f, and 25g are approximately the same size as the upper surfaces 22a, 23a, and 24a of the heating elements 22, 23, and 24. These holes 25e, 25f, and 25g are for releasing a part (excess part) of the heat conductive sheet 27 in the region of the heating elements 22, 23, and 24. The heat sink 25 is formed by pressing one aluminum plate.

  The thermally conductive sheet 27 is set to a size that can cover the heating elements 22, 23, and 24 integrally. The thickness is slightly thicker than, for example, the lowest gap (distance) between the upper surface 23a of the heat generating element 23 and the inner surface of the upper plate portion 25c of the heat sink 25 among the heat generating elements 22, 23, and 24. Is set.

  Then, the heat conductive sheet 27 is placed on the heat generating elements 22, 23, 24, and then the heat sink 25 is disposed, and the locking claws 25 b of the both side portions 25 a are formed on the side surfaces of the printed circuit board 21. Lock to and fix. Thereby, the heat conductive sheet 27 is pressed against the upper surfaces 22a, 23a, 24a of the heat generating elements 22, 23, 24 by the heat sink 25.

  The heat conductive sheet 27 has an excessive thickness portion corresponding to the heat generating elements 22, 23, and 24 having different heights from the corresponding holes 25e, 25f, and 25g of the upper plate portion 25c of the heat sink 25 as shown in the figure. Stick out. Thereby, the heat conductive sheet 27 can be reasonably interposed between the heat generating elements 22, 23, 24 having different heights and the heat sink 25, and elasticity due to the thickness of the heat conductive sheet 27 can be reduced. .

  As a result, the reaction force to the heat sink 25 can be significantly reduced, and the stress applied to the heat sink 25 by the deformation of the heat sink 25 and the heating elements 22, 23, 24 can be reduced. Then, the heat of the heating elements 22, 23, 24 can be transmitted to the heat sink 25 satisfactorily.

  Note that the top surface of each heat generating element 22, 23, 24 mounted on the printed circuit board has a top surface around the holes 25e, 25f, 25g of the heat sink 25 as in the heat generating elements according to the first to third embodiments described above. When providing a protrusion partly, you may provide the protrusion which concerns on 1st thru | or 3rd embodiment mentioned above around each hole 25e, 25f, 25g of the heat sink 25. FIG. As a result, the heat of the heating element can be efficiently radiated to the heat sink 25.

  In the fourth embodiment, when the heat sink 25 is provided with protrusions around the holes 25e, 25f, and 25g, the protrusions bite into the heat conductive sheet 27 and try to escape from the holes 25e, 25f, and 25g. The heat conductive sheet 27 can be brought into close contact with the protrusion.

1 is an assembled perspective view of a heat dissipation structure in an electronic apparatus according to a first embodiment of the present invention. It is a partial perspective view which shows the shape of the lower surface facing the heat generating element of the heat sink shown in FIG. FIG. 3 is a cross-sectional view taken along arrows III-III in a state where a heat sink is assembled on the heat generating element shown in FIG. 1. It is principal part sectional drawing of the thermal radiation structure in the electronic device concerning the 2nd Embodiment of this invention. It is an assembly perspective view of the thermal radiation structure in the electronic device concerning the 3rd Embodiment of this invention. It is a partial perspective view which shows the shape of the lower surface facing the heat generating element of the heat sink shown in FIG. FIG. 7 is a cross-sectional view taken along arrows VII-VII in a state in which a heat conductive sheet and a heat sink are assembled on the heating element shown in FIG. 5. FIG. 6 is a cross-sectional view taken along arrows VIII-VIII in a state where a heat conductive sheet and a heat sink are assembled on the heating element shown in FIG. 5. It is principal part sectional drawing of the thermal radiation structure in the electronic device concerning the 4th Embodiment of this invention. It is sectional drawing of the conventional heat dissipation structure when the several heat generating element from which height differs is mounted on the printed circuit board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 1a Upper surface 2, 3, 4 Heating element 2a, 3a, 4a Upper surface (heat generating part)
5 Heat sink 6 Thermal conductive rubber sheet 11 Printed circuit board 11a Upper surface 11b Heat sink fixing portion 11c Screw hole 12 Heating element 12a Upper surface 12b Protruding portion 12c Upper surface of protruding portion 12d Area other than protruding portion of upper surface 12a 13 Heat sink 13a Lower surface 13b Region facing the upper surface of the protruding portion 13c Region facing the region other than the protruding portion of the heating element 13d, 13d 'Projecting portion 13e, 13e' Lower surface 13f Mounting hole 13g Hole 14 Screw 15 Thermal conductive grease 17, 27 Thermal conductivity Sheet 21 Printed circuit board 21a Upper surface 21b Locking portion 22, 23, 24 Heating element 22a, 23a, 24a Upper surface (heat generating portion)
25 heat sink 25a side portion 25b locking claw 25c upper plate portion 25e, 25f, 25g hole

Claims (4)

In the heat dissipation structure in electronic equipment that dissipates the heat of the heating element mounted on the printed circuit board through the heat sink,
The heating element is formed with a protrusion on a part of the surface in contact with the heat sink,
The heat sink has a surface facing the protruding portion of the heat generating element in contact with the protruding portion of the heat generating element, and a protrusion contacting the region is formed in a region facing the region other than the protruding portion. Heat dissipation structure in electronic equipment. In the heat dissipation structure in electronic equipment that dissipates the heat of the heating element mounted on the printed circuit board through the heat sink,
The heating element is formed with a protrusion on a part of the surface in contact with the heat sink,
The heat sink is opposed to a region other than the protrusion of the heat generating element, and a protrusion having the same height as or lower than the protrusion is formed.
A heat dissipation structure in an electronic device, wherein a heat conductive grease is interposed between a surface of the heat generating element on a side in contact with the heat sink and the heat sink. In the heat dissipation structure in electronic equipment that dissipates the heat of the heating element mounted on the printed circuit board through the heat sink,
The heating element is formed with a protrusion on a part of the surface in contact with the heat sink,
A heat conductive sheet is interposed between the heating element and the heat sink,
The heat sink is provided with a hole for allowing a part of the heat conductive sheet to escape in a region facing the protruding portion of the heat generating element, and for bringing the heat conductive sheet into contact with a region other than the protruding portion of the heat generating element. A heat dissipation structure in an electronic device, characterized in that a protrusion is formed. In a heat dissipation structure in an electronic device that dissipates heat by transmitting heat to the heat sink by interposing a heat conductive sheet between a plurality of heat generating elements mounted on a printed circuit board and a heat sink.
The heat sink is formed with a hole for allowing a part of the heat conductive sheet to escape in a region facing each heat generating element, and the heat conductive sheet is brought into contact with each heat generating element substantially uniformly. Heat dissipation structure in electronic equipment.

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