JP2015126104A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissipate heat generated from a heating element efficiently.SOLUTION: A metal plate 20 is fastened for a heat dissipation member 12 by means of three fastening members 41, 42, 43, so that a region Z1 surrounded by the fastening members 41, 42, 43 in the metal plate 20 includes at least a part of the mounting part 26 in the metal plate 20 for mounting each electronic component 11. With such an arrangement, even if a circuit board 10a deforms to warp for the heat dissipation member 12 by the heat generated from each electronic component 11, warpage for the heat dissipation member 12 due to fastening of the fastening members 41, 42, 43 is suppressed in a region Z1 surrounded by the fastening members 41, 42, 43. Consequently, the region Z1 in the metal plate 20 surrounded by the fastening members 41, 42, 43 functions as a heat transmission path between the metal plate 20 and heat dissipation member 12.

Description

  The present invention relates to an electronic device.

  Conventionally, for example, a heat dissipation structure for a heating element in an electronic device is disclosed in Patent Document 1. As shown in FIG. 4, in Patent Document 1, a printed circuit board 102 (circuit board) on which a heat generating electronic component 101 (heating element) is mounted is accommodated in a case 103 made of aluminum or the like. A heat dissipation pattern 104 made of copper foil or the like is integrally provided on the insulating substrate 102 a of the printed circuit board 102. The heat generating electronic component 101 is fixed to the heat radiation pattern 104. A cylindrical boss portion 105 is integrally formed with the case 103. Further, a heat radiating nut 106 made of aluminum or the like having good heat conduction efficiency is insert-molded in the boss portion 105. The heat radiating nut 106 has a protruding portion 106 a that protrudes toward the insulating substrate 102 a side from an end portion of the boss portion 105 on the insulating substrate 102 a side, and an exposed portion 106 b that is exposed outside the case 103. The printed circuit board 102 is supported by the heat radiating nut 106 by screwing screws 107 (male screws) to the heat radiating nut 106 in a state where the heat radiating pattern 104 and the protrusion 106 a are in contact with each other. According to this, the heat generated from the heat generating electronic component 101 is radiated out of the case 103 from the heat radiation pattern 104 via the heat radiation nut 106.

JP-A-9-32467

  However, since the linear expansion coefficient of the insulating substrate 102a and the linear expansion coefficient of the heat radiation pattern 104 are different, the printed circuit board 102 is deformed so as to warp against the heat radiation nut 106 due to heat generated from the heat generating electronic component 101. There is. When the printed circuit board 102 is deformed so as to warp with respect to the heat radiating nut 106, the contact area between the heat radiating pattern 104 and the protruding portion 106 a is reduced, and the heat generated from the heat generating electronic component 101 is reduced from the heat radiating pattern 104. It becomes difficult to be discharged out of the case 103 through the heat radiating nut 106.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an electronic device that can efficiently dissipate heat generated from a heating element.

  An electronic device that solves the above problem includes a circuit board having an insulating substrate and a metal plate that is bonded to the insulating substrate and on which a heating element is mounted, and is a heat dissipation member that is thermally coupled to the metal plate The metal plate is fastened to the heat radiating member by at least three fastening members, and the region surrounded by the fastening member in the metal plate is the heating element in the metal plate. Includes at least a portion of the mounting portion on which the is mounted.

  For example, when the metal plate is fastened to the heat radiating member with one fastening member, the linear expansion coefficient of the insulating substrate is different from the linear expansion coefficient of the metal plate. If it deform | transforms so that it may warp with respect to a heat radiating member, there exists a possibility that the heat transfer path | route between a metal plate and a heat radiating member may become only the site | part by which the metal plate and the heat radiating member are fastened by the fastening member. Further, when the metal plate is fastened to the heat radiating member with two fastening members, the metal plate and the heat radiating member are deformed so that the circuit board is warped against the heat radiating member due to the heat generated from the heating element. There is a possibility that the heat transfer path between the two portions is only on the portion where the metal plate and the heat radiating member are fastened by each fastening member and on the line connecting the two portions. Thus, the heat transfer path between the metal plate and the heat radiating member is only the portion where the metal plate and the heat radiating member are fastened by the fastening member, or the metal plate and the heat radiating member are each fastening member. If it becomes only on the site | part fastened by and the line which connects both site | parts, the heat | fever emitted from a heat generating body cannot be thermally radiated efficiently.

  Therefore, the metal plate is fastened to the heat radiating member with at least three fastening members, and the region surrounded by the fastening member on the metal plate includes at least a part of the mounting portion on which the heating element on the metal plate is mounted. . According to this, even if the circuit board tries to deform so as to warp against the heat radiating member due to the heat generated from the heating element, in the region surrounded by the fastening member in the metal plate, the heat radiating member Against warping. Therefore, the area | region enclosed by the fastening member in a metal plate can be functioned as a heat transfer path | route between a metal plate and a heat radiating member. And since the area | region enclosed by the fastening member in a metal plate contains at least one part of the mounting part in which the heat generating body in a metal plate is mounted, the area | region enclosed by the fastening member in a metal plate for the heat emitted from a heat generating body It is possible to efficiently dissipate heat to the heat dissipating member.

  In the above electronic device, the metal plate passes through a bonding portion bonded to the first surface of the insulating substrate and a through hole formed in the insulating substrate, and is opposite to the first surface of the insulating substrate. And a protruding portion having the mounting portion, the wiring pattern being bonded to the second surface of the insulating substrate, and the metal plate having the insulating substrate attached to the insulating substrate. It is preferable to be thermally coupled to the heat dissipation member without intervention. According to this, compared with the case where the insulating substrate is interposed between the metal plate and the heat radiating member, the heat generated from the heating element can be efficiently radiated from the metal plate to the heat radiating member.

In the electronic device, it is preferable that a heat transfer portion is interposed between the metal plate and the heat dissipation member.
According to this, heat transfer from the metal plate to the heat radiating member in the heat generated from the heating element can be promoted by the heat transfer section, so that the heat generated from the heating element can be radiated more efficiently.

In the above electronic device, it is preferable that the heat transfer portion is heat dissipation grease.
According to this, for example, compared with a case where a heat transfer plate is interposed as a heat transfer portion between the metal plate and the heat dissipation member, it is possible to easily fill a gap between the metal plate and the heat dissipation member, Heat generated from the heating element can be dissipated more efficiently.

  According to this invention, the heat generated from the heating element can be efficiently radiated.

FIG. 6 is a top view illustrating an electronic device according to the embodiment. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. The longitudinal cross-sectional view which shows the electronic device in a prior art example.

Hereinafter, an embodiment in which an electronic device is embodied will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the electronic device 10 includes a metal plate 20 on which a plurality of (four in the present embodiment) electronic components 11 as heating elements are mounted, and a laminate on a part of the upper surface of the metal plate 20. And a circuit board 10 a including a wiring pattern 31 and a fixing plate 32 stacked on the upper surface of the insulating substrate 30. Furthermore, the electronic device 10 includes a heat dissipation member 12 that is thermally coupled to the metal plate 20. The heat radiating member 12 is made of aluminum which is a material different from that of the metal plate 20 and is connected to the ground.

  The metal plate 20 is laminated on the upper surface of the heat dissipation member 12. The metal plate 20 is made of a flat copper plate having a thickness of 0.5 mm and is patterned into a predetermined shape. Further, a part of the metal plate 20 is bent. Specifically, the metal plate 20 is bent upward (valley fold) at the first fold curve P1, bent downward (mountain fold) at the second fold curve P2, and further the third fold curve. It is bent downward (mountain fold) at P3 and is bent upward (valley fold) at the fourth folding curve P4.

  The metal plate 20 includes a protrusion 21 formed between the second fold curve P2 and the third fold curve P3, and a first outer peripheral portion 22 extending from the first fold curve P1 to the opposite side of the second fold curve P2. And a first bent portion 23 that connects the first outer peripheral portion 22 and the protruding portion 21. Furthermore, the metal plate 20 includes a second outer peripheral portion 24 extending from the fourth folding curve P4 to the opposite side of the third folding curve P3, and a second bent portion 25 connecting the second outer peripheral portion 24 and the protruding portion 21. Have. The protruding portion 21, the first outer peripheral portion 22, and the second outer peripheral portion 24 extend in parallel to each other.

  As shown by a broken line in FIG. 1, the first outer peripheral portion 22 has a pair of extending portions 22 a and 22 b that extend on both sides of the protruding portion 21 and are located below the protruding portion 21 and are L-shaped in plan view. Is formed. The second outer peripheral portion 24 is formed with a pair of extending portions 24 a and 24 b having an L shape in plan view that extends on both sides of the protruding portion 21 and is positioned below the protruding portion 21. The distal ends of the extending portions 22a and 24a are opposed to each other, and the distal ends of the extending portions 22b and 24b are opposed to each other.

  As shown in FIG. 2, a flat insulating substrate 30 is bonded to the upper surfaces of the first outer peripheral portion 22 and the second outer peripheral portion 24 in a stacked state. Therefore, the first outer peripheral portion 22 and the second outer peripheral portion 24 form an adhesion portion that is bonded to the lower surface (first surface) of the insulating substrate 30 in the metal plate 20. A through hole 30 h through which the protruding portion 21 of the metal plate 20 can pass is formed in the central portion of the insulating substrate 30. The upper surface of the protrusion 21 protrudes from the upper surface of the insulating substrate 30 (second surface opposite to the first surface of the insulating substrate 30) through the through hole 30h.

  As shown in FIG. 1, a wiring pattern 31 is bonded to the upper surface of the insulating substrate 30 in a laminated state. The wiring pattern 31 is made of a flat copper plate having a thickness of 0.5 mm and is patterned into a predetermined shape. The wiring pattern 31 is disposed at an overlapping position from the first outer peripheral portion 22 of the metal plate 20 to the second outer peripheral portion 24 via the extending portions 22a and 24a, and is overlapped with the extending portions 22b and 24b. Absent. The insulating substrate 30 insulates the metal plate 20 and the wiring pattern 31 from each other.

  Further, a fixed plate 32 is bonded to the upper surface of the insulating substrate 30 in a stacked state. The fixed plate 32 is made of a flat copper plate having a thickness of 0.5 mm, and is disposed at a position overlapping the extending portions 22 b and 24 b of the metal plate 20. The upper surface of the protruding portion 21, the upper surface of the wiring pattern 31, and the upper surface of the fixing plate 32 are located on the same plane. The wiring pattern 31 and the fixing plate 32 are separated from each other and are not electrically connected.

  An insulating substrate 30 is laminated on the upper surfaces of the first outer peripheral portion 22 and the second outer peripheral portion 24 of the metal plate 20 with an adhesive (not shown) applied thereto. Further, the wiring pattern 31 and the fixing plate 32 are laminated on the upper surface of the insulating substrate 30 with an adhesive (not shown) applied thereto. Then, the wiring pattern 31 and the fixing plate 32 are pressed in the stacking direction by a flat plate-shaped pressing tool (not shown) extending over the upper surface of the wiring pattern 31 and the upper surface of the fixing plate 32. Then, the adhesion between the first outer peripheral portion 22 and the second outer peripheral portion 24 of the metal plate 20 and the insulating substrate 30, the adhesion between the insulating substrate 30 and the wiring pattern 31, and the insulating substrate 30 and the fixing plate 32. The circuit board 10a is formed.

  Each electronic component 11 is mounted on the upper surface of the protruding portion 21 near the extending portions 22b and 24b. Therefore, the protruding portion 21 has a plurality of mounting portions 26 (four in this embodiment) on which the respective electronic components 11 are mounted. Here, the mounting portion 26 refers to a portion of the protruding portion 21 that is in contact with the electronic component 11 and is thermally coupled to the electronic component 11. Each electronic component 11 is provided with a lead 11a. The lead 11 a of each electronic component 11 is electrically connected to the wiring pattern 31.

  The metal plate 20 is fastened to the heat dissipation member 12 by three fastening members 41, 42, 43. In this embodiment, each fastening member 41, 42, 43 is a bolt. The fastening member 41 is disposed near the extending portions 22 a and 24 a in the protruding portion 21 and is screwed into the heat radiating member 12 through the protruding portion 21. The fastening member 42 is disposed at a corner portion of the extending portion 22b, and is screwed into the heat radiating member 12 through the fixing plate 32, the insulating substrate 30, and the extending portion 22b. The fastening member 43 is disposed at a corner of the extending portion 24b and is screwed into the heat radiating member 12 through the fixing plate 32, the insulating substrate 30, and the extending portion 24b.

  A region Z <b> 1 surrounded by the fastening members 41, 42, and 43 in the metal plate 20 includes at least a part of the mounting portion 26 on which each electronic component 11 in the metal plate 20 is mounted. The region Z1 is a triangular region in plan view surrounded by the straight lines while connecting the fastening members 41, 42, and 43 with straight lines.

  As shown in FIGS. 2 and 3, heat radiation grease 27 as a heat transfer portion is interposed between the metal plate 20 and the heat radiation member 12. As the heat radiation grease 27, for example, silicon grease is used. As shown in FIG. 3, a seat 12 a protrudes from the upper surface of the heat radiating member 12 that overlaps the protrusion 21. Further, the heat radiating member 12 is formed with an annular groove 12b surrounding the seat portion 12a. When the heat dissipation grease 27 is applied between the metal plate 20 and the heat dissipation member 12, the heat dissipation grease 27 flows into the annular groove 12b. According to this, as the heat radiation grease 27 flows into the annular groove 12b, the heat radiation grease 27 is prevented from flowing between the metal plate 20 and the seat portion 12a. And the metal plate 20 and the seat part 12a are directly contacting by the fastening of the fastening member 41. FIG.

  A current (for example, 120 A) flowing through the wiring pattern 31 is supplied to a load (not shown) that is electrically connected to the heat dissipation member 12. The heat dissipation member 12, the seat 12 a, the protruding portion 21 of the metal plate 20, the electronic component 11, the wiring pattern 31, and a current path for a current flowing through the load and returning to the heat dissipation member 12 are secured.

Next, the operation of this embodiment will be described.
For example, consider a case where the metal plate 20 is fastened to the heat radiating member 12 with one fastening member. In this case, since the linear expansion coefficient of the insulating substrate 30 and the linear expansion coefficient of the metal plate 20 are different, if the circuit board 10a is deformed so as to warp against the heat radiating member 12 due to heat generated from each electronic component 11, There is a possibility that the heat transfer path between the metal plate 20 and the heat radiating member 12 is only the portion where the metal plate 20 and the heat radiating member 12 are fastened by the fastening member.

  Consider a case where the metal plate 20 is fastened to the heat dissipation member 12 with two fastening members. In this case, when the circuit board 10 a is deformed so as to warp against the heat radiating member 12 due to heat generated from each electronic component 11, the heat transfer path between the metal plate 20 and the heat radiating member 12 is There is a possibility that the heat radiating member 12 may be only on the part fastened by each fastening member and on the line connecting the two parts.

  Thus, the heat transfer path between the metal plate 20 and the heat radiating member 12 is only the part where the metal plate 20 and the heat radiating member 12 are fastened by the fastening member, or the metal plate 20 and the heat radiating member 12 However, if it becomes only on the site | part fastened by each fastening member and the line which connects both site | parts, the heat | fever emitted from each electronic component 11 cannot be thermally radiated efficiently.

  Therefore, in the present embodiment, the metal plate 20 is fastened to the heat radiating member 12 with the three fastening members 41, 42, 43, and the region Z1 surrounded by the fastening members 41, 42, 43 in the metal plate 20 is a metal. The board 20 includes at least a part of a mounting portion 26 on which each electronic component 11 is mounted. According to this, even if the circuit board 10a is deformed so as to warp against the heat radiating member 12 due to the heat generated from each electronic component 11, the region Z1 surrounded by the fastening members 41, 42, 43 in the metal plate 20 is used. Then, the fastening members 41, 42, and 43 are pressed against the heat radiating member 12 by being fastened, and are prevented from warping against the heat radiating member 12. Therefore, the region Z <b> 1 surrounded by the fastening members 41, 42, and 43 in the metal plate 20 functions as a heat transfer path between the metal plate 20 and the heat dissipation member 12.

  And the area | region Z1 enclosed by the fastening members 41,42,43 in the metal plate 20 contains at least one part of the mounting part 26 in which each electronic component 11 in the metal plate 20 is mounted. Furthermore, by fastening the fastening members 41, 42, and 43, the region Z <b> 1 surrounded by the fastening members 41, 42, and 43 in the protruding portion 21 of the metal plate 20 and the upper surface that overlaps the protruding portion 21 in the heat radiating member 12 radiate heat. Surface contact is facilitated via the grease 27. For this reason, the heat generated from each electronic component 11 is efficiently radiated to the heat radiating member 12 through the region Z1 surrounded by the fastening members 41, 42, and 43 in the protruding portion 21 of the metal plate 20 and the heat radiating grease 27.

In the above embodiment, the following effects can be obtained.
(1) The metal plate 20 is fastened to the heat radiating member 12 with the three fastening members 41, 42, and 43, and the region Z <b> 1 surrounded by the fastening members 41, 42, and 43 in the metal plate 20 is At least a part of the mounting portion 26 on which the electronic component 11 is mounted is included. According to this, even if the circuit board 10a is deformed so as to warp against the heat radiating member 12 due to the heat generated from each electronic component 11, the region Z1 surrounded by the fastening members 41, 42, 43 in the metal plate 20 is used. Then, when the fastening members 41, 42, 43 are fastened, the heat dissipation member 12 is prevented from warping. And the area | region Z1 enclosed by the fastening members 41,42,43 in the metal plate 20 becomes a heat transfer path between the metal plate 20 and the heat radiating member 12, and the heat generated from each electronic component 11 is generated in the metal plate 20. Heat can be efficiently radiated to the heat radiating member 12 through the region Z1 surrounded by the fastening members 41, 42, and 43.

  (2) For example, as the electronic device 10, the metal plate on which the electronic component 11 is mounted and the wiring pattern in which the lead 11 a of the electronic component 11 is electrically connected to the upper surface of the insulating substrate 30 have predetermined shapes, respectively. A configuration in which the heat dissipation member 12 is fixed to the lower surface of the insulating substrate 30 is also conceivable. With this configuration, since the insulating substrate 30 is interposed between the metal plate and the heat radiating member 12, heat generated from the electronic component 11 is not easily radiated to the heat radiating member 12. However, in this embodiment, the metal plate 20 is thermally coupled to the heat radiating member 12 without the insulating substrate 30 interposed therebetween, and therefore the insulating substrate 30 is interposed between the metal plate 20 and the heat radiating member 12. Compared with the case where it exists, the heat emitted from the electronic component 11 can be efficiently radiated from the metal plate 20 to the heat radiating member 12.

  (3) The heat radiation grease 27 is interposed between the metal plate 20 and the heat radiation member 12. According to this, heat transfer from the metal plate 20 to the heat radiating member 12 in heat generated from each electronic component 11 can be promoted by the heat radiating grease 27, so that heat generated from each electronic component 11 can be more efficiently generated. It can dissipate heat.

  (4) The heat dissipation grease 27 has a gap between the metal plate 20 and the heat dissipation member 12 as compared with a case where a heat transfer plate is interposed between the metal plate 20 and the heat dissipation member 12, for example. Easy to fill. Therefore, the heat generated from each electronic component 11 can be radiated more efficiently.

  (5) The fixing plate 32 is laminated on the upper surface of the insulating substrate 30. According to this, compared with the case where the fixing plate 32 is not laminated on the upper surface of the insulating substrate 30, the strength of the circuit board 10a can be ensured.

  (6) By laminating the fixing plate 32 on the upper surface of the insulating substrate 30, the thickness of the portion of the circuit board 10 a that overlaps the extending portions 22 b and 24 b of the metal plate 20 in the stacking direction, and the metal plate 20 on the circuit board 10 a. It is possible to make the thickness in the stacking direction of the portion overlapping each of the extending portions 22a and 24a the same. Therefore, for example, the adhesion between the first outer peripheral portion 22 and the second outer peripheral portion 24 of the metal plate 20 and the insulating substrate 30 is a flat plate-like press extending over the upper surface of the wiring pattern 31 and the upper surface of the fixed plate 32. Using only the tool, the wiring pattern 31 and the fixing plate 32 can be performed simply by pressing the pressing tool in the stacking direction, and the manufacturing of the circuit board 10a can be simplified.

In addition, you may change the said embodiment as follows.
In embodiment, the metal plate 20 should just be fastened with the at least 3 fastening member 41,42,43 with respect to the heat radiating member 12, for example, the metal plate 20 is used for the heat radiating member using four or more fastening members. 12 may be fastened.

  In the embodiment, the three fastening members 41, 42, and 43 may be screwed into the heat dissipation member 12 through the protruding portion 21. For example, the fastening member 41 is disposed near the extending portions 22a and 24a in the protruding portion 21, and the fastening member 42 is disposed on the side edge side of the protruding portion 21 near the extending portion 22b. 43 may be arrange | positioned at the side edge side near the extension part 24b in the protrusion part 21. As shown in FIG. According to this, by fastening the fastening members 41, 42, 43, the projecting portion 21 and the upper surface of the heat radiating member 12 that overlaps the projecting portion 21 are easily brought into surface contact via the heat radiating grease 27. The heat generated from the heat can be efficiently radiated to the heat radiating member 12 through the region Z1 surrounded by the fastening members 41, 42, and 43 in the metal plate 20.

In the embodiment, the fixing plate 32 may not be laminated on the upper surface of the insulating substrate 30.
In the embodiment, a heat transfer plate as a heat transfer unit may be interposed between the metal plate 20 and the heat dissipation member 12.

In the embodiment, the heat dissipation grease 27 may not be interposed between the metal plate 20 and the heat dissipation member 12, and the metal plate 20 and the heat dissipation member 12 may be in direct contact.
In the embodiment, in the electronic device 10, the metal plate on which the electronic component 11 is mounted and the wiring pattern in which the lead 11 a of the electronic component 11 is electrically connected to the upper surface of the insulating substrate 30 have predetermined shapes, respectively. A configuration in which the heat dissipation member 12 is fixed to the lower surface of the insulating substrate 30 may be possible.

  In the embodiment, the thickness, material, and the like of the metal plate 20, the wiring pattern 31, and the fixing plate 32 are not particularly limited. For example, the metal plate 20, the wiring pattern 31, and the fixing plate 32 may be formed of a conductive metal material such as aluminum.

In embodiment, you may use the thermal radiation grease which used the liquid metal, the ceramic, etc. for the main component as a heat-transfer part, for example.
In the embodiment, the heat radiating member 12 may be formed of a conductive material other than aluminum.

  In the embodiment, the fastening members 41, 42, 43 may be other than bolts. In short, the fastening members 41, 42, and 43 may be any members that can fasten the metal plate 20 and the heat dissipation member 12.

In the embodiment, the number of electronic components 11 is not particularly limited.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The metal plate is fastened to the heat dissipation member by three fastening members.

  Z1 ... area, 10 ... electronic device, 10a ... circuit board, 11 ... electronic component as a heating element, 12 ... heat dissipation member, 20 ... metal plate, 21 ... projection, 26 ... mounting portion, 27 ... as heat transfer portion Radiation grease, 30 ... insulating substrate, 30h ... through hole, 31 ... wiring pattern, 41, 42, 43 ... fastening member.

Claims (4)

An insulating substrate;
A circuit board having a metal plate that is bonded to the insulating substrate and on which a heating element is mounted,
An electronic device having a heat dissipation member that is thermally coupled to the metal plate,
The metal plate is fastened with at least three fastening members to the heat dissipation member,
The area surrounded by the fastening member in the metal plate includes at least a part of a mounting portion on the metal plate on which the heating element is mounted. The metal plate is a surface that is bonded to the first surface of the insulating substrate and a surface opposite to the first surface of the insulating substrate through a through hole formed in the insulating substrate. A protrusion that protrudes from the surface and has the mounting portion, and
A wiring pattern is bonded to the second surface of the insulating substrate,
The electronic apparatus according to claim 1, wherein the metal plate is thermally coupled to the heat dissipation member without the insulating substrate interposed therebetween.   The electronic apparatus according to claim 2, wherein a heat transfer portion is interposed between the metal plate and the heat dissipation member.   The electronic apparatus according to claim 3, wherein the heat transfer unit is a heat dissipation grease.