JP2009064866A - Electronic device with heat-dissipating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-dissipating structure capable of efficiently providing heat dissipation for an electronic device wherein an insulating substrate mounted with a heating device, and to provide a heat-dissipating member are connected via a heat conduction material. <P>SOLUTION: In the electronic device 10 equipped with the heating device 16, the insulating substrate 14 mounted with the heating device on a mounted surface 14a, and the heat dissipation member 12 connected to the reverse surface 14b, opposed to the mounted surface of the insulating substrate via the heat conducting member 26, the insulating substrate is provided with heat conductive material escape portions 24, 34, 44, 54, 64, 74, 84, and 94 which release the conducting material nearby the heating device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic device having a heat dissipation structure, and in particular, a heat conductive material escape portion for releasing a heat conductive material interposed between the insulating substrate and the heat dissipation member is provided on the insulating substrate in the vicinity of the mounted heating element. The present invention relates to an electronic device.

  In recent years, in electronic elements such as semiconductor elements mounted on an insulating substrate, the amount of heat generation tends to increase with the increase in integration and driving power. There has been proposed one having a heat dissipation structure that effectively connects to a heat sink.

  In such a configuration, in order to improve the adhesion between the insulating substrate and the heat radiating member, a thermal conductive grease that is a thermal conductive material may be applied (see Patent Documents 1 and 2).

  Specifically, in Patent Document 1, the insulating substrate on which the semiconductor element is mounted and the housing is mounted and the heat sink disposed below the solder substrate are soldered in a state where the joint surfaces are in surface contact with each other. The connected heat radiating plate and the cooler disposed below the heat radiating plate are connected via a heat conductive grease, which is a heat conductive material, in a state in which the lower convex heat radiating plate is in contact with the cooler.

Further, in Patent Document 2, a heat sink on which a housing covering an insulating substrate on which a semiconductor element is mounted and a heat dissipation case disposed below the heat sink are formed over the entire width of at least one of the heat sink and the heat dissipation case. In a state in which the joint surfaces having the grooves are in contact with each other, they are connected via thermal conductive grease, which is a thermal conductive material injected into the grooves.
JP 2005-039081 A JP 2005-101259 A

  However, in the configuration proposed in Patent Document 1, when heat conduction grease, which is a heat conduction material, is uniformly applied to the heat radiating plate and fixed to the cooler, the side portion between the heat radiating plate and the cooler is arranged. There is a tendency for the thermal grease to protrude, and a post-treatment for removing the protruding thermal grease is necessary, which is complicated in the work process. In addition, if the protruding thermal conductive grease is left untreated, the oil component droops when the oil component contained in the thermal conductive grease is separated due to aging or temperature change, which is not preferable. Moreover, this situation is the same between the heat radiating plate and the heat radiating case in the configuration proposed in Patent Document 2.

  The present invention has been made in view of such circumstances, and provides a heat dissipation structure capable of efficiently realizing heat dissipation in an electronic device in which an insulating substrate on which a heating element is mounted and a heat dissipation member are connected via a heat conductive material. With the goal.

  In order to achieve the above object, the present invention connects a heating element, an insulating substrate on which the heating element is mounted on a mounting surface, and a back surface of the insulating substrate facing the mounting surface via a heat conductive material. In the electronic apparatus comprising the heat dissipation member, a heat conductive material escape portion for allowing the heat conductive material to escape is provided on the insulating substrate in the vicinity of the heat generating element.

  Further, according to the present invention, in addition to the first feature, the heat conducting material escape portion is a through hole provided through the mounting surface and the back surface of the insulating substrate in the vicinity of the heating element. This is the second feature.

  In addition to the second feature of the present invention, the heat generating element includes a heat radiating plate portion connected to the mounting surface of the insulating substrate and parallel to the mounting surface. When the length of one side is a, the length of the other side of the heat radiating plate portion is b, and the thickness of the insulating substrate is t, a heat generation diffusion region parallel to the mounting surface is A third feature is that when the length is defined as a square range having a + 2t and the length of the other side being b + 2t, the through-hole is disposed in the vicinity of the outside of the heat generation diffusion region. .

  In addition to the first feature, the present invention has a fourth feature in that the heat conducting material escape portion is a groove provided on the back surface of the insulating substrate in the vicinity of the heating element. .

  In addition to the fourth feature of the present invention, the heat generating element includes a heat radiating plate portion connected to the mounting surface of the insulating substrate and parallel to the mounting surface. When the length of one side is a, the length of the other side of the heat radiating plate portion is b, and the thickness of the insulating substrate is t, a heat generation diffusion region parallel to the mounting surface is A fifth feature is that when the length is a + 2t and the length of the other side is defined as a quadrangular range of b + 2t, the groove is disposed in the vicinity of the inside of the heat diffusion region.

  According to the sixth aspect of the present invention, in addition to any one of the second to fifth features, the heat conducting material escape portion has a width that increases from the mounting surface to the back surface of the insulating substrate. Features.

  According to the first feature of the present invention, the insulating substrate in the vicinity of the heat generating element is provided with a heat conductive material escape portion for allowing the heat conductive material to escape, so that the heat insulating element is mounted between the insulating substrate on which the heat generating element is mounted and the heat radiating member. Adhesion through the heat conducting material can be improved, and efficient heat dissipation is possible. Here, it is possible to surely prevent the heat conductive material from unnecessarily protruding from the side surfaces of the insulating substrate and the heat radiating member. In addition, unnecessary voids can be reliably prevented from occurring in the heat conducting material.

  According to the second feature of the present invention, the heat conducting material escape portion is a through hole provided through the mounting surface and the back surface of the insulating substrate in the vicinity of the heat generating element, so that the amount of the heat conducting material is increased. When there is a large amount of heat conduction material, it is possible to reliably overflow an excessive amount of heat conduction material onto the surface of the insulating substrate, enabling efficient heat radiation, and heat conduction material on the side surfaces of the insulation substrate and the heat radiation member. Can be reliably prevented from protruding. Furthermore, when a plurality of heat generating elements are mounted on an insulating substrate, a through hole exists between adjacent heat generating elements, which is effective for unnecessary heat interference via the insulating substrate between adjacent heat generating elements. Can be reduced.

  According to the third feature of the present invention, the through hole is disposed in the vicinity of the outside of the heat generating diffusion region of the heat generating element, thereby ensuring a range in which heat radiation from the back surface of the heat generating element is effectively performed. A through-hole can be disposed on the outer side, and unnecessary thermal interference between adjacent heating elements can be more effectively reduced.

  According to the fourth feature of the present invention, the heat conducting material escape portion is a groove provided on the back surface of the insulating substrate in the vicinity of the heat generating element, so that heat existing between the insulating substrate and the heat dissipation member is present. The contact surface area of the conductive material can be increased, efficient heat dissipation can be achieved, and the heat conductive material can be reliably prevented from protruding to the side surfaces of the insulating substrate and the heat dissipation member.

  According to the fifth feature of the present invention, the groove is disposed in the vicinity of the inner side of the heat generating diffusion region of the heat generating element, so that the heat radiation from the back surface of the heat generating element is effectively performed. A groove that can increase the contact area with the heat dissipating member can be disposed, enabling efficient heat dissipation.

  According to the sixth feature of the present invention, the heat conducting material escape portion has a shape whose width increases from the mounting surface to the back surface of the insulating substrate, so that the heat conducting material is interposed between the insulating substrate and the heat dissipation member. When applying and pressing, the heat conductive material can be uniformly interposed between the insulating substrate and the heat radiating member, and the surface area of the heat conductive material is increased by increasing the surface area of the insulating substrate with respect to the heat radiating member. The heat dissipation effect can be further increased and the heat dissipation can be improved more reliably.

  Hereinafter, an electronic device having a heat dissipation structure in each embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the figure, the x-axis, y-axis, and z-axis form a three-axis orthogonal coordinate system.

(First embodiment)
First, an electronic device having a heat dissipation structure according to a first embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a schematic perspective view of an electronic device having a heat dissipation structure in the present embodiment. 2 is a schematic top view of the electronic device having the heat dissipation structure in the present embodiment as viewed in FIG. 1 along the negative direction of the z-axis, and FIG. 3 is an enlarged view taken along line AA in FIG. It is sectional drawing.

  As shown in FIG. 1, in an electronic device 10 having a heat dissipation structure in the present embodiment, an insulating substrate 14 is placed on a metal heat dissipation member 12 such as aluminum. The insulating substrate 14 has a two-layer structure in which a resin insulating layer is formed on a metal layer such as aluminum. As will be described in detail later, between the heat radiating member 12 and the insulating substrate 14, a heat conducting material that conducts heat from the insulating substrate 14 side toward the heat radiating member 12 side while improving their adhesion. Is applied and interposed. In addition, although heat conductive grease can be used as such a heat conductive material, liquid, gel-like and particulate heat conductive materials can also be used, and an adhesive having heat conductivity can also be used. Moreover, the heat radiating member 12 is not limited to a metal member, and, for example, a graphite member can be used.

  A plurality of heating elements 16 that are electronic elements such as transistors are mounted on the insulating substrate 14. Although not shown, the heating element 16 is bonded to the metal layer of the insulating substrate 14 by solder or the like corresponding to the window portion opened in the insulating layer so that the metal layer is exposed on the insulating substrate 14. When the electronic element constituting the heat generating element 16 is driven, the heat generating element 16 generates heat, and the heat is transmitted from the metal layer of the insulating substrate 14 to the heat conducting material and further to the heat radiating member 12.

  In addition to the heating element 16, an input terminal 18, an output terminal 20, and a relay terminal 22 are mounted on the insulating substrate 14. For example, when the heating element 16 is a transistor that performs a switching operation, the input terminal 18 has two terminals, a P terminal and an N terminal connected to a smoothing capacitor or the like that stabilizes the operation of the transistor, and an output. The terminal 20 has three terminals of a U-phase terminal, a V-phase terminal, and a W-phase terminal for three-phase AC applied to a load such as a motor or a compressor. In such a case, the relay terminal 22 has a plurality of terminals connected to a controller or the like that controls the operation of the transistor.

  Here, in the present embodiment, as shown in FIGS. 2 and 3, the insulating substrate 14 in the vicinity of the heating element 16 is provided with a plurality of through holes 24 that are heat conducting material escape portions for letting out the heat conducting material. Yes. The heat generating element 16 has a heat radiating plate portion 16a, and the heat radiating plate portion 16a is bonded to the metal layer of the insulating substrate 14 by solder or the like corresponding to the window portion opened in the insulating layer of the insulating substrate 14. It is the pad part to be done. 2 and 3, the input terminal 18, the output terminal 20, and the relay terminal 22 are not shown. In FIG. 3, the heat conductive material is denoted by reference numeral 26, and the heat dissipation member 12, the insulating substrate 14, and the like are schematically illustrated. Between.

  The through-hole 24 has a wall surface 24a that is an inner wall surface that is symmetric with respect to the central axis Z and penetrates between a mounting surface 14a that is a surface on which the heating element 16 of the insulating substrate 14 is mounted and a back surface 14b that faces the mounting surface 14a. . In such a through hole 24, the inner diameter corresponding to the width of the heat conducting material escape portion is constant. The through hole 24 is also disposed between the plurality of heat generating elements 16 mounted on the insulating substrate 14. In FIG. 3, only one through hole 24 is shown for convenience.

  Next, the process of fixing the insulating substrate 14 mounted with the heat generating element 16 to the heat radiating member 12 will be described in detail.

  First, as shown in FIGS. 2 and 3, a heat conductive material 26 is applied to the back surface 14 b of the insulating substrate 14 on which the heat generating element 16 is mounted or the upper surface of the heat radiating member 12, and then the insulating substrate 14 is attached to the heat radiating member in this state. 12 is pressure-bonded with a predetermined load. Thereafter, the insulating substrate 14 is fixed to the heat dissipation member 12 with a fastening member such as a bolt (not shown).

  Here, when the insulating substrate 14 is crimped onto the heat radiating member 12 in a state where the heat conductive material 26 is applied to the insulating substrate 14 or the heat radiating member 12, the heat conductive material 26 is pushed and an arrow in FIG. As shown by 26a, it penetrates into the through hole 24 and escapes in the positive direction of the z-axis.

  As described above, in this configuration, an excessive amount of the heat conductive material 26 can be reliably overflowed to the surface of the insulating substrate 14 while being accommodated in the through hole 24, and the insulating substrate 14 and the heat dissipation member 12 can be It is possible to improve the adhesion and to efficiently dissipate heat, and to reliably prevent the heat conductive material 26 from protruding from the side surfaces of the insulating substrate 14 and the heat radiating member 12 with certainty. Further, the through holes 24 exist between the adjacent heating elements 16 on the insulating substrate 14, and unnecessary thermal interference between the adjacent heating elements 16 via the insulating substrate can be effectively reduced.

  Next, a more detailed configuration for disposing the through hole 24 in the vicinity of the heating element 16 mounted on the insulating substrate 14 will be described in detail with reference to FIGS.

  4 is an enlarged view in which the schematic top view of the electronic device having the heat dissipation structure in this embodiment of FIG. 2 is further partially enlarged, and FIG. 5 is a cross-sectional view taken along the line BB of FIG. . In FIG. 4, the heating element 16 is not shown.

  First, a heat diffusion region where heat generated by the heat generating element 16 diffuses toward the heat radiating member 12 through the insulating substrate 14 will be considered.

  The heat generating element 16 emits the heat generating element 16 because the heat radiating plate portion 16a is a pad portion bonded to the metal layer of the insulating substrate 14 corresponding to the window portion opened in the insulating layer of the insulating substrate 14. The heat is transmitted from the heat radiating plate portion 16a to the insulating substrate 14. Here, the boundary of the diffusion range in which the heat generated by the heat generating element 16 is transmitted from the heat radiating plate portion 16a to the insulating substrate 14 is defined by an angle α that is 45 ° in the negative direction of the z axis with respect to the xy plane. Therefore, if the thickness of the insulating substrate 14 in the z-axis direction is t, the lengths of heat spreading in the x and y directions when the heat reaches the back surface 14b of the insulating substrate 14 are t. . Further, if the length of the rectangular heat radiating plate portion 16a in the x direction is a and the length in the y direction is b, when heat reaches the back surface 14b of the insulating substrate 14, it diffuses on the xy plane. The area to be processed is a rectangular area whose length in the x direction is a + 2t and whose length in the y direction is b + 2t. That is, if a rectangular region that diffuses on the xy plane when heat reaches the back surface 14b of the insulating substrate 14 is defined as a heat generation diffusion region 28, the length in the x direction is a + 2t, It becomes a rectangular region parallel to the xy plane whose length is b + 2t.

  Here, in the heat generating diffusion region 28, the heat transmitted from the heat radiating plate portion 16a of the heat generating element 16 is diffused and propagated, so the through hole 24 must be disposed in the heat generating diffusion region 28. For example, the heat propagation path in the heat generating diffusion region 28 can be secured as it is, and if the through hole 24 is disposed near the outside of the heat generating diffusion region 28, the continuity of the insulating substrate 14 is hindered by the through hole 24, Heat transfer to the outer periphery of the heat generating diffusion region 28, that is, typically to the adjacent heat generating element 16 can be blocked. Further, in such a case, the heat diffusion from the heat radiating plate 16a of the heat generating element 16 to the insulating substrate 14 is symmetric with respect to the central axis of the heat radiating plate 16a in the z-axis direction, that is, the central axis of the heat generating diffusion region 28 in the z-axis direction. Therefore, if the through holes 24 are arranged in the vicinity of the outside of each of the four sides of the heat generation diffusion region 28, it is possible to effectively block heat radiation to the adjacent heat generating elements 16 in four directions. .

  Therefore, in this configuration, the through hole 24 is disposed in the vicinity of the outside of the heat generation diffusion region 28 in consideration of the heat diffusion state from the heat radiating plate portion 16a of the heat generation element 16. In consideration of the rectangular shape of the heat radiating plate portion 16 a of the heat generating element 16, the through holes 24 are arranged near the outer sides of the four sides of the heat generating diffusion region 28. Here, the through hole 24 being positioned near the outside of the heat generating diffusion region 28 means that the through hole 24 is in contact with the boundary of the heat generating diffusion region 28 or is disposed near the outside of the boundary. Say.

  As described above, according to such a configuration, the through hole 24 is disposed in the vicinity of the outside of the heat generation diffusion region 28 of the heat generating element 16, so that a range in which heat radiation from the back surface of the heat generating element 16 is effectively performed can be achieved. The through-hole 24 can be arranged outside while securing it, and unnecessary thermal interference between adjacent heating elements 16 can be effectively reduced.

  Next, in the electronic device having the heat dissipation structure in the present embodiment, a modification of the through hole disposed near the outside of the heat generating diffusion region 28 of the heat generating element 16 will be described in detail with reference to FIGS. explain.

  FIG. 6 is a partial cross-sectional view showing a modification of the through hole of the electronic device having the heat dissipation structure in the present embodiment, and FIG. 7 is another modification of the through hole of the electronic device having the heat dissipation structure in the present embodiment. FIG. 6 and 7, the cross section is taken in a positional relationship corresponding to the cross sectional view shown in FIG. 3, but the heat radiating member 12, the heat generating element 16, and the heat conducting material 26 are not shown.

  As shown in FIG. 6, the through hole 34 of the present modified example has a mounting surface 14 a that is a surface on which the heat generating element 16 of the insulating substrate 14 is mounted and a back surface 14 b that faces the mounting surface 14 b. It is the same that the wall surface 34a that is symmetrical with respect to the central axis Z passes through between the mounting surface 14a and the back surface 14b. The wall surface 34a has an inner diameter of the through hole 34 that corresponds to the width of the heat conducting material escape portion. It is different in that it is inclined with respect to the z-axis so as to expand as it goes to.

  In this way, the through hole 34 is shaped so that its inner diameter increases from the mounting surface 14 a to the back surface 14 b of the insulating substrate 14, so that the heat conductive material 26 is interposed between the insulating substrate 14 and the heat dissipation member 12. When applied and pressed, the amount of excess heat conductive material 26 can be increased, and the heat conductive material 26 can be evenly interposed between the insulating substrate 14 and the heat radiating member 12, and the heat can be radiated. By increasing the surface area of the insulating substrate with respect to the member, the contact surface area of the heat conducting material can be increased, the heat dissipation effect can be further increased, and the heat dissipation can be improved more reliably.

  Next, as shown in FIG. 7, the through hole 44 of another modified example penetrates between the mounting surface 14a of the insulating substrate 14 and the back surface 14b opposite to the through hole 34 of the modified example described above. Then, it is the same that it has a wall surface 44a symmetrical about the central axis Z and has an inner diameter that increases as it goes from the mounting surface 14a to the back surface 14b, but the wall surface 44a is on the way to the back surface 14b of the insulating substrate 14, The difference is that the wall surface 44b is more inclined with respect to the z-axis so that the inner diameter of the through hole 44 is further increased.

In this way, the through hole 44 is shaped so that its inner diameter gradually increases from the mounting surface 14 a to the back surface 14 b of the insulating substrate 14, so that the accommodation amount of the excess heat conductive material 26 is further increased. As a result, the heat conductive material 26 can be more uniformly interposed between the insulating substrate 14 and the heat dissipation member 12, and the surface area of the heat conductive material can be increased by further increasing the surface area of the insulating substrate with respect to the heat dissipation member. It can be further increased, the heat dissipation effect is further increased, and the heat dissipation can be improved more reliably.
(Second Embodiment)
Next, an electronic device having a heat dissipation structure according to the second embodiment of the present invention will be described in detail with reference to FIGS. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  8 is a schematic top view of the electronic device having the heat dissipation structure in the present embodiment as viewed in FIG. 1 along the negative direction of the z-axis, and FIG. 9 is an enlarged cross-sectional view taken along the line CC in FIG. It is.

  In the present embodiment, as shown in FIGS. 8 and 9, the configuration described in the first embodiment is linear in the y-axis direction instead of the through holes 24, 34, and 44 in the first embodiment. The main difference is that the groove 54 extending to the insulating substrate 14 is provided in the insulating substrate 14, and the remaining configuration is the same.

  More specifically, the insulating substrate 14 in the vicinity of the heat generating element 16 is provided with a plurality of grooves 54 that are heat conduction material escape portions for allowing the heat conduction material to escape. The grooves 54 are formed as recesses on the back surface 14b facing the mounting surface 14a that is the surface on which the heat generating element 16 of the insulating substrate 14 is mounted, and are arranged symmetrically with respect to the central axis Z, respectively, in the x-axis direction and the y-axis. There are two pairs of side wall surfaces 54a facing each other in the direction, and an upper wall surface 54b that closes upward. That is, in the groove 54, the side wall surface 54a is a vertical surface parallel to the xz plane or the yz plane, and the distance between the opposed side wall surfaces 54a, which is the width of the heat conducting material escape portion, is constant. It is. In FIG. 9, only one groove 54 is shown for convenience.

  Next, the process of fixing the insulating substrate 14 mounted with the heat generating element 16 to the heat radiating member 12 will be described in detail.

  As shown in FIGS. 8 and 9, a heat conductive material 26 is applied to the back surface 14 b of the insulating substrate 14 on which the heat generating element 16 is mounted or the upper surface of the heat radiating member 12, and then the insulating substrate 14 is placed on the heat radiating member 12 in this state. It is the same as in the first embodiment that the insulating substrate 14 is fixed to the heat radiating member 12 with a fastening member such as a bolt (not shown).

  Here, when the insulating substrate 14 is pressure-bonded onto the heat radiating member 12 in a state where the heat conductive material 26 is applied to the insulating substrate 14 or the heat radiating member 12, the heat conductive material 26 is pushed and an arrow in FIG. As indicated by 26a, it enters the groove 54 and escapes in the positive direction of the z-axis.

  As described above, in such a configuration, it is possible to increase the contact surface area of the heat conductive material 26 existing between the insulating substrate 14 and the heat dissipation member 12 while accommodating an excessive amount of the heat conductive material 26 in the groove 54. In addition, it is possible to efficiently dissipate heat, and to reliably prevent the heat conductive material 26 from unnecessarily protruding from the side surfaces of the insulating substrate 14 and the heat radiating member 12.

  Next, a more detailed configuration for disposing the groove 54 in the vicinity of the heating element 16 mounted on the insulating substrate 14 will be described in detail with reference to FIGS.

  FIG. 10 is an enlarged view in which the schematic top view of the electronic device having the heat dissipation structure in this embodiment of FIG. 8 is further partially enlarged, and FIG. 11 is a cross-sectional view taken along the line DD of FIG. . In FIG. 10, the heating element 16 is not shown.

  First, also in the present embodiment, the heat generation diffusion region 28 in which the heat generated by the heat generating element 16 diffuses toward the heat radiating member 12 through the insulating substrate 14 is t, and the thickness of the insulating substrate 14 in the z-axis direction is t. If the length in the x direction of the rectangular heat sink 16a of the heat generating element 16 is a and the length in the y direction is b, the length in the x direction is a + 2t, and the length in the y direction is b + 2t. It can be defined as a rectangular region parallel to the xy plane.

  Here, since heat transmitted from the heat radiating plate portion 16a of the heat generating element 16 is diffused and propagated in the heat generating diffusion region 28, if the groove 54 is disposed in the heat generating diffusion region 28, Corresponding to the heat propagation path in the heat generation diffusion region 28, the groove 54 can be reliably arranged. Since an excessive amount of the heat conducting material 26 is accommodated in the groove 54, the groove 54 exists between the insulating substrate 14 and the heat radiating member 12 with respect to the heat propagation path in the heat generating diffusion region 28. The region where the contact surface area of the heat conductive material 26 is increased can be made to correspond reliably, and heat can be radiated more reliably from the heating element 16 toward the heat radiating member 12.

  Therefore, in such a configuration, the groove 54 is disposed on the back surface of the insulating substrate 14 in the vicinity of the inside of the heat generation diffusion region 28 in consideration of the heat diffusion state from the heat radiating plate portion 16a of the heat generation element 16. is there. Here, the phrase that the groove 54 is arranged in the vicinity of the inside of the heat generation diffusion region 28 means that the groove 54 is in contact with the boundary of the heat generation diffusion region 28 or in the vicinity of the inside of the boundary. . Further, here, the groove 54 has been described as having a shape extending linearly in the y-axis direction. However, the groove 54 is of course not limited, and has a shape extending linearly in the x-axis direction. Alternatively, it may extend in a curved shape, a zigzag shape, a cross shape or the like instead of a linear shape. Further, the number of the grooves 54 is not limited, and an appropriate number can be set in consideration of the size of the heat diffusion region 28, the contents of the groove processing, and the like.

  As described above, in this configuration, the groove 54 is disposed in the vicinity of the inner side of the heat generation diffusion region 28 of the heat generating element 16, so that the insulating substrate 14 and the heat propagation path in the heat generation diffusion region 28 are arranged. The region where the contact surface area of the heat conductive material 26 existing between the heat radiating member 12 is increased can be reliably handled, and heat can be radiated more reliably from the heat generating element 16 toward the heat radiating member 12. it can.

  Next, in the electronic device having the heat dissipation structure in the present embodiment, a modified example of the groove disposed in the vicinity of the heat diffusion region 28 of the heat generating element 16 will be described in detail with reference to FIGS. To do.

  FIG. 12 is a partial cross-sectional view showing a modification of the groove of the electronic device having the heat dissipation structure in the present embodiment, and FIGS. 13 to 15 show another modification of the groove of the electronic device having the heat dissipation structure in the present embodiment. FIG. 12 to 15, the cross section is taken in a positional relationship corresponding to the cross sectional view shown in FIG. 3, but the heat radiating member 12, the heat generating element 16, and the heat conducting material 26 are not shown.

  As shown in FIG. 12, the groove 64 of this modification is a recess provided on the back surface 14b of the insulating substrate 14 that faces the mounting surface 14a that is the surface on which the heat generating element 16 is mounted. However, the linearly extending in the y-axis direction is the same, but the pair of side wall surfaces 64a extending in the y-axis direction while facing each other in the x-axis direction are used as the heat conduction material relief portion. The distance between the side wall surfaces 64a corresponding to the width of each of the surfaces is inclined with respect to the plane P parallel to the yz plane so as to increase from the mounting surface 14a toward the back surface 14b.

  In this way, the groove 64 is shaped so that the distance between the side wall surfaces 64a increases from the mounting surface 14a to the back surface 14b of the insulating substrate 14, so that heat is generated between the insulating substrate 14 and the heat dissipation member 12. When the conductive material 26 is applied and pressed, the amount of excess heat conductive material 26 can be increased, and the heat conductive material 26 can be uniformly interposed between the insulating substrate 14 and the heat dissipation member 12. In addition, since the surface area of the insulating substrate with respect to the heat radiating member is increased, the contact surface area of the heat conducting material can be increased, the heat radiating effect is further increased, and the heat radiating property can be improved more reliably.

  Next, as shown in FIG. 13, the groove 74 of another modified example is a recess provided on the back surface 14b of the insulating substrate 14 with respect to the groove 64 of the modified example described above, and is linear in the y-axis direction. In the same manner, the distance between the side wall surfaces 74a increases from the mounting surface 14a of the insulating substrate 14 toward the back surface 14b, but the side wall surface 74a faces the back surface 14b of the insulating substrate 14. In the middle, the side wall surface 74b is more inclined with respect to the plane P parallel to the yz plane so that the distance between the side wall surfaces increases.

  Thus, the groove 74 is shaped so that the distance between the side wall surfaces 74a, 74b gradually increases from the mounting surface 14a of the insulating substrate 14 toward the back surface 14b, so that the excess heat conductive material 26 is removed. The capacity can be further increased, and the heat conductive material 26 can be more uniformly interposed between the insulating substrate 14 and the heat radiating member 12, and the surface area of the insulating substrate with respect to the heat radiating member can be further increased. The contact surface area of the conductive material can be further increased, the heat dissipation effect can be further increased, and the heat dissipation can be improved more reliably.

  Next, as shown in FIG. 14, the groove 84 of still another modified example is a recess provided on the back surface 14 b of the insulating substrate 14 with respect to the groove 64 of the above-described modified example, and extends in the y-axis direction. The distance between the side wall surfaces 84a extends linearly from the mounting surface 14a of the insulating substrate 14 toward the back surface 14b, but the side wall surfaces 84a are the same as the mounting surface of the insulating substrate 14. It is different in contact on the 14a side. In addition, the top part where the side wall surfaces 84a are in contact with each other on the mounting surface 14a side of the insulating substrate 14 may have an R shape.

  As described above, the groove 84 has a shape in which the distance between the side wall surfaces 84a is increased from the mounting surface 14a to the back surface 14b of the insulating substrate 14, thereby increasing the amount of the heat conductive material 26 accommodated. Thus, the heat conductive material 26 can be uniformly interposed between the insulating substrate 14 and the heat dissipation member 12, and the surface area of the heat conductive material is increased by increasing the surface area of the insulating substrate with respect to the heat dissipation member. In addition to the fact that the heat radiation effect can be further increased and the heat radiation performance can be further improved, the side wall surfaces 84a are in contact with each other on the mounting surface 14a side of the insulating substrate 14, and thus the step of forming the groove 84 is possible. Can be simplified.

  Next, as shown in FIG. 15, the groove 94 of still another modified example is a recess provided in the back surface 14 b of the insulating substrate 14 with respect to the groove 84 of the modified example described above, and extends in the y-axis direction. The distance between the side wall surfaces 94a increases linearly from the mounting surface 14a of the insulating substrate 14 toward the back surface 14b, but the side wall surface 94a extends to the back surface 14b of the insulating substrate 14. On the way, the side wall surface 94b is more inclined with respect to the plane P parallel to the yz plane so that the distance between the side wall surfaces increases.

  In this way, the groove 94 is shaped so that the distance between the side wall surfaces 94a and 94b gradually increases from the mounting surface 14a to the back surface 14b of the insulating substrate 14, so that the excess heat conductive material 26 is removed. The capacity can be further increased, and the heat conductive material 26 can be more uniformly interposed between the insulating substrate 14 and the heat radiating member 12, and the surface area of the insulating substrate with respect to the heat radiating member can be further increased. The contact surface area of the conductive material can be further increased, the heat dissipation effect can be further increased, and the heat dissipation can be improved more reliably.

  In the present invention, the type, arrangement, number, and the like of the members are not limited to the above-described embodiments, and the constituent elements thereof are appropriately replaced with those having the same operational effects, and the gist of the invention is not deviated. Of course, it can be appropriately changed within the range.

  As described above, in the present invention, in an electronic device in which an insulating substrate on which a heating element is mounted and a heat radiating member are connected via a heat conductive material, a heat radiating structure capable of efficiently realizing heat radiation can be provided. It is expected that it can be widely applied to an electronic device having a heating element because of its general purpose universal character.

1 is a schematic perspective view of an electronic device having a heat dissipation structure in a first embodiment of the present invention. It is a schematic top view of an electronic device having a heat dissipation structure in the present embodiment. It is an expanded sectional view by the AA line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is sectional drawing by the BB line of FIG. It is a fragmentary sectional view in the modification of the electronic device which has a heat dissipation structure in this embodiment. It is a fragmentary sectional view in another modification of an electronic device which has a heat dissipation structure in this embodiment. It is a schematic top view of the electronic device which has the heat dissipation structure in the 2nd Embodiment of this invention. It is an expanded sectional view by the CC line of FIG. It is the elements on larger scale of FIG. It is sectional drawing by the DD line of FIG. It is a fragmentary sectional view in the modification of the electronic device which has a heat dissipation structure in this embodiment. It is a fragmentary sectional view in another modification of an electronic device which has a heat dissipation structure in this embodiment. It is a fragmentary sectional view in another modification of an electronic device which has a heat dissipation structure in this embodiment. It is a fragmentary sectional view in another modification of an electronic device which has a heat dissipation structure in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electronic device 12 ... Heat dissipation member 14 ... Insulation board 14a ... Mounting surface 14b ... Back surface 16 ... Heating element 16a ... Heat sink 18 ... Input terminal 20 ... Output terminal 22 ... Relay terminal 24 ... Through hole 24a ... Wall surface 26 ... Thermal conductive material 28 ... Heat diffusion region 34 ... Through hole 34a ... Wall surface 44 ... Through hole 44a ... Wall surface 44b ... Wall surface 54 ... Groove 54a ... Side wall surface 54b ... Upper wall surface 64 ... ... Groove 64a ... Side wall surface 74 ... Groove 74a ... Side wall surface 74b ... Side wall surface 84 ... Groove 84a ... Side wall surface 94 ... Groove 94a ... Side wall surface 94b ... Side wall surface

Claims (6)

In an electronic device comprising: a heat generating element; an insulating substrate on which the heat generating element is mounted on a mounting surface; and a heat radiating member connected to a back surface of the insulating substrate facing the mounting surface via a heat conductive material. ,
An electronic device, wherein a heat conduction material escape portion for allowing the heat conduction material to escape is provided on the insulating substrate in the vicinity of the heat generating element.   2. The electronic device according to claim 1, wherein the heat conducting material escape portion is a through hole provided through the mounting surface and the back surface of the insulating substrate in the vicinity of the heat generating element.   The heat generating element has a heat radiating plate portion connected to the mounting surface of the insulating substrate and parallel to the mounting surface, and the length of one side of the heat radiating plate portion is a, When the length of the side is b and the thickness of the insulating substrate is t, the heat-diffusion region parallel to the mounting surface has a length of one side of a + 2t, and the length of the other side. 3. The electronic device according to claim 2, wherein the through-hole is disposed in the vicinity of the outside of the heat diffusion region when defined as a square range of b + 2t.   The electronic device according to claim 1, wherein the heat conducting material escape portion is a groove provided on the back surface of the insulating substrate in the vicinity of the heating element.   The heat generating element has a heat radiating plate portion connected to the mounting surface of the insulating substrate and parallel to the mounting surface, and the length of one side of the heat radiating plate portion is a, When the length of the side is b and the thickness of the insulating substrate is t, the heat-diffusion region parallel to the mounting surface has a length of one side of a + 2t, and the length of the other side. 5. The electronic device according to claim 4, wherein when defined as a square range of b + 2t, the groove is arranged in the vicinity of the inside of the heat generation diffusion region.   6. The electronic device according to claim 2, wherein a width of the heat conductive material escape portion is increased from the mounting surface to the back surface of the insulating substrate.

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