JP2008041762A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an electronic component from having high temperature by allowing heat generated from the electronic component of an electronic device to escape to a heat reservoir effectively. <P>SOLUTION: In an electronic device 1, a heat reservoir 3 is enclosed in a container 2 having thermal conductivity, one surface 4a of an electronic component 4 having heat-generating properties is made to be in contact with one surface 2a of the container 2, a plurality of convexes 2c are provided on one inner surface 2b on the underside of one surface 2a of the container 2, and one inner surface 2b is made to be inclined so that a portion 2d directly under the electronic component 4 is farther from one surface 2a than a portion 2e not directly under the electronic component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device including electronic components such as a power transistor, a microprocessor, a choke coil, a laser diode, and an electric motor, and more particularly to suppressing high temperature when the electronic component operates and generates heat. It is.

  Some electronic devices include electronic components that generate heat and become high temperature when operated, such as a power transistor, a microprocessor, a choke coil, a laser diode, and an electric motor. When such an exothermic electronic component reaches a temperature higher than a predetermined temperature, the electronic component or the electronic device malfunctions, and further, damage such as destruction of the built-in circuit or peripheral circuit of the electronic device occurs. In order to prevent the occurrence of such harm, various measures have been proposed in the past for suppressing the temperature of electronic components from becoming high.

  For example, in Patent Document 1 below, cooling is performed by enclosing a metal having a melting point lower than the melting point or decomposition temperature of the hollow container and lower than the upper limit operating temperature of the electronic component inside the hollow container formed of a high thermal conductivity material. By attaching the element to the upper surface of the electronic component, heat generated from the electronic component is absorbed and stored by self-melting of the encapsulated metal, and the electronic component is prevented from being heated to a high temperature.

Further, in Patent Document 2 below, Al ₂ O ₃ in which a circuit pattern is formed on the upper surface and electronic components are mounted.
In a circuit board composed of an insulating plate made of a member and a substrate made of an aluminum member in close contact with the lower surface of the insulating plate, a heat storage material made of a paraffin member in a uniform cavity sealed against the entire surface of the substrate The heat generated by the electronic component is absorbed by self-melting of the heat storage material to store the heat, and the electronic component is prevented from becoming high temperature.

  Further, in Patent Document 3 below, a heat dissipation sheet formed by laminating a metal sheet such as aluminum or copper and an adhesive heat conductive member containing a heat softening material such as paraffin wax is used as an electronic component and a heat The metal sheet is connected to the electronic component, and the heat conductive member is connected to the heat dissipating member, and the heat generated from the electronic component is transferred from the solid to the liquid of the heat conductive member. The change absorbs heat and transmits it to the heat dissipating member to suppress the electronic component from becoming high temperature.

  In Patent Document 4 below, a slurry in which a phase-change substance is encapsulated in a small amount is enclosed in a container or a flexible bag, and the container or bag is brought into contact with the electronic component, thereby generating heat from the electronic component. Is absorbed and stored by the phase change from the solid to the liquid of the slurry, and the electronic component is prevented from becoming high temperature.

  In Patent Document 5 below, an electronic component is mounted on the upper surface of a circuit board, a casing containing a solid coolant such as paraffin is fixed to the lower surface of the circuit board, and solid cooling is performed on the inner surface of the ceiling portion of the casing. By providing the fin so as to come into contact with the agent over a wide area, the heat generated from the electronic component is absorbed by the melting of the solid coolant to be stored, and the electronic component is prevented from becoming high temperature.

  Furthermore, in the following Patent Document 6, heat storage material such as paraffin is sandwiched between an electronic component and a heat sink, embedded in a heat sink, or attached to a cylindrical fin of the heat sink, thereby generating heat from the electronic component. It absorbs heat by melting the heat storage material to store heat, and suppresses the electronic component from becoming high temperature.

JP 2004-152905 A Japanese Patent No. 2798656 JP 2002-305271 A US Patent No. 5007478 Japanese Utility Model Publication No. 2-15786 JP-A-8-148618

  As mentioned above, by attaching a heat storage body such as metal, paraffin, or slurry directly or indirectly to the electronic component, the heat generated from the electronic component is released to the heat storage body and the electronic component is prevented from becoming hot. Was. However, if a gap containing air is interposed between the heat storage body and the electronic component, the heat conductivity of the air is low, so that heat generated from the electronic component is efficiently released to the heat storage body, and the electronic component becomes high temperature. Can not be suppressed. In particular, when the heat storage body is sealed in the container as in Patent Documents 1, 2, 4, 5, and 6, air enters the container and a gap is easily formed. In this case, the air can be substantially removed from the container by heating the heat storage body into a liquid state and pouring it gently into the container. However, even if it does so, air may remain from the inside of the container and a gap may be formed. In addition, since air is contained in the liquid heat storage body and it is very difficult to completely remove the air, the heat storage body repeats the phase change between the solid and the liquid in the container. The air may appear and gaps may be formed. As described above, when the air gap is formed in the container, the air moves, so that the air gap spreads between the heat storage body and the electronic component. In particular, when the electronic component is attached to the upper surface of the container as in Patent Documents 2 and 5, the heat storage body melts in the container, so that the air moves upward in the container, and the heat storage body and the electronic component are accumulated. A gap of air spreads between the two and becomes easy to intervene.

  The present invention solves the above-mentioned problems, and the problem is to efficiently release heat generated from the electronic components of the electronic device to the heat storage body and suppress the electronic components from becoming high temperature. There is.

  The present invention includes an electronic component, a heat storage body, and a thermally conductive container encapsulating the heat storage body, one surface of the electronic component is in contact with one surface of the container, and one inner surface on the back side of the one surface of the container In the electronic device provided with a plurality of convex portions, one inner surface of the container is inclined so that a portion directly behind the electronic component is farther from one surface than a portion not directly behind.

  In this way, by inclining one inner surface that is the root of the convex portion in the container, even if air exists in the container, the air moves due to melting of the heat storage body, etc. Since the gap is formed by accumulating in the non-back part instead of accumulating in the back part of the electronic component, it is possible to prevent the air gap from spreading between the heat storage body and the electronic component. Further, the contact area between the part on the electronic component side of the container and the heat storage body is widened by inclining one inner surface on the back side of one surface of the container in contact with the electronic component and providing a plurality of convex portions on the one inner surface. be able to. Therefore, when the electronic component operates and generates heat, it is possible to efficiently release the heat generated from the electronic component to the heat storage body through the container, and to prevent the electronic component from reaching a high temperature.

  Moreover, in one Embodiment of this invention, the convex part is formed in plate shape in the said electronic device.

  By doing so, even if air is present in the container, it is difficult for the air to collect around the convex portion, and it is possible to prevent an air gap from being interposed between the convex portion and the heat storage body. Can do. For this reason, it becomes possible to more efficiently escape the heat generated from the electronic component to the heat storage body from almost the entire surface of each convex portion of the container, and to suppress the electronic component from becoming high temperature.

  Moreover, in one Embodiment of this invention, the convex part is formed in the column shape in the said electronic device.

  By doing in this way, since the fluidity | liquidity of the thermal storage body melt | dissolved in the container becomes high, when inject | pouring the melted thermal storage body in a container, it can make it easy to escape air from the inside of a container. Moreover, even if air exists in the container, the air does not accumulate around the convex portion, and it is possible to prevent the air gap from being interposed between the convex portion and the heat storage body. For this reason, it becomes possible to suppress the heat | fever from an electronic component more efficiently and to escape from the whole surface of each convex part of a container to a thermal storage body, and an electronic component becoming high temperature.

  Moreover, in one Embodiment of this invention, in the said electronic device, one inner surface of the container provided with the convex part inclines so that it may become far from one surface as it goes to the center from an end.

  By doing in this way, even if air exists in the container, the air can be reliably guided so as to accumulate in a non-back portion of the electronic component at the end of one inner surface of the container. For this reason, it becomes possible to prevent reliably that the space | gap of an air expands and interposes between a thermal storage body and an electronic component.

  Furthermore, in one embodiment of the present invention, in the electronic device, one surface of the container in contact with the electronic component is directed in a direction opposite to the direction of gravity.

  By doing in this way, even if air exists in the container, when the heat storage body melts in the container, the heat storage body moves downward due to its own weight, and the air moves upward so that one inner surface of the container It can be surely guided so as to accumulate in the non-back part of the electronic component. For this reason, it becomes possible to more reliably prevent the air gap from being spread and interposed between the heat storage body and the electronic component and around the convex portion directly behind the electronic component.

  According to the present invention, it is possible to widen the contact area between the portion of the container on the electronic component side and the heat storage body while preventing the air gap from being widened and interposed between the heat storage body and the electronic component. When the electronic component operates and generates heat, it is possible to efficiently release the heat generated from the electronic component to the heat storage body and to prevent the electronic component from reaching a high temperature.

  FIG. 1 is a cross-sectional view of an electronic apparatus 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 3 is a cross-sectional view taken along line BB in FIG. The electronic device 1 includes a container 2, a heat storage body 3, and an electronic component 4. The container 2 is formed of a metal material having thermal conductivity and heat dissipation such as aluminum. The outer shape of the container 2 has a rectangular parallelepiped shape (including a cubic shape). The heat storage body 3 is made of a material, such as paraffin wax, that absorbs heat and stores heat during phase change from solid to liquid (during melting). As a specific example of the heat storage body 3, synthetic wax FT115 manufactured by Nippon Seiwa Co., Ltd. can be used. The melting point of this synthetic wax is 114 ° C. The electronic component 4 is composed of an electronic component having a heat generating property that generates heat and becomes high temperature by operating, such as a power transistor, a microprocessor, a choke coil, a laser diode, or an electric motor. The melting point of the heat accumulator 3 is lower than the melting point of the material of the container 2 or the decomposition temperature of the container 2 and is equal to or lower than the operation upper limit temperature of the electronic component 4.

  In the container 2, the heat storage body 3 after melting is enclosed. The heat storage body 3 is in close contact with the inner surface of the container 2. An electronic component 4 is attached to one surface (upper surface) 2 a of the container 2 facing in the direction opposite to the direction of gravity (downward in FIGS. 1 to 3). One surface (lower surface) 4a of the electronic component 4 and one surface 2a of the container 2 are in close contact with each other via an adhesive sheet or grease having thermal conductivity.

  A plurality of convex portions 2 c are provided on one inner surface 2 b on the back side of one surface 2 a of the container 2 so as to protrude with respect to the heat storage body 3. The convex part 2c is formed in plate shape as shown in FIGS. 2 and 3, the left and right end portions of the convex portion 2 c are continuous with the left and right inner surfaces of the container 2. As shown in FIG. 2, the inner surface 2b of the container 2 that is the root of the convex portion 2c is inclined such that the portion 2d that is directly behind the electronic component 4 is farther from the one surface 2a than the portion 2e that is not directly back. More specifically, the inner surface 2b of the container 2 is inclined in an arc shape when viewed from the side so as to become farther from the one surface 2a from the end toward the center. FIG. 4 is a perspective view of one inner surface 2b and the convex portion 2c of the container 2. FIG. In FIG. 4, in order to make the shape easy to understand, only one inner surface 2b and the convex portion 2c of the container 2 are cut out and shown upward. As shown in FIG. 4, a plurality of plate-like convex portions 2 c are erected in parallel at a predetermined interval on one inner surface 2 b inclined in an arc shape of the container 2.

  As shown in FIG. 2, the heat accumulator 3 is formed on the entire back portion 2 d of the electronic component 4 on the inner surface 2 b of the container 2, most of the non-back portion 2 e, and most of the surface of the convex portion 2 c. It is in close contact. In the vicinity of the left and right end portions of the inner surface 2b of the container 2, that is, the portion surrounded by the end portion of the non-true back portion 2e of the electronic component 4 on the side opposite to the back portion 2d and the roots of the left and right end portions of the convex portions 2c. Is formed with a gap 5 containing air.

  As a manufacturing method of the electronic device 1, in a normal atmosphere, first, the heat storage body 3 is heated and melted (liquid state), and then injected into the container 2 from an opening (not shown) provided in the container 2. At this time, most of the air contained in the container 2 is replaced with the heat storage body 3 and discharged to the outside of the container 2, but a part of the air may remain in the container 2. The heat storage body 3 injected into the container 2 moves downward due to its own weight. Further, the air remaining in the container 2 moves upward and accumulates in the vicinity of the left and right end portions of the one inner surface 2b, and a gap 5 is formed at the location. Next, the heat storage body 3 is solidified (in a solid state) in the container 2 by, for example, natural cooling. Then, the surface of the heat storage body 3 that does not face the gap 5 and the inner surface of the container 2 are in close contact with each other. Next, the opening of the container 2 is closed with a lid or the like (not shown) to prevent the heat storage body 3 from leaking out of the container 2. Then, the electronic component 4 is attached by bringing the one surface 4a of the electronic component 4 into close contact with the surface (directly above) the portion 2d of the surface 2a of the container 2.

  As another manufacturing method of the electronic device 1, first, a powder (solid state) heat storage body 3 is injected into the container 2 from an opening (not shown) provided in the container 2 in a normal atmosphere. At this time, most of the air contained in the container 2 is replaced with the heat storage body 3 and discharged outside the container 2, but a part remains in the container 2. Next, for example, the heat storage body 3 is heated and melted together with the container 2 (in a liquid state). Then, the heat storage body 3 moves downward by its own weight in the container 2. Further, the air remaining in the container 2 moves upward and accumulates in the vicinity of the left and right end portions of the one inner surface 2b, and a gap 5 is formed at the location. After this, the heat storage body 3 is solidified in the container 2 as described above, the opening of the container 2 is closed with a lid or the like, and the electronic component 4 is attached to the true part of the portion 2d of the one surface 2a of the container 2.

Furthermore, as another manufacturing method, a solid heat storage body 3 may be formed in advance in a shape that matches the inner shape of the container 2 by using a mold that matches the inner shape of the container 2. In this case, the solid heat storage body 3 having the above shape is inserted into the container 2, and then the container 2 is covered to put the heat storage body 3 into the container 2.

  After the electronic device 1 is manufactured, when the electronic component 4 operates to generate heat, a portion (ceiling portion) where the generated heat is sandwiched between the one surface 2a and the one inner surface 2b of the container 2 from the entire one surface 4a of the electronic component 4 Then, the heat is transferred from the inner surface 2b of the container 2 and the surface of the convex portion 2c to the heat storage body 3, and the heat storage body 3 is melted. At this time, since the heat storage body 3 absorbs heat from the electronic component 4 and stores the heat, the electronic component 4 is suppressed from becoming a high temperature that is equal to or higher than the operation upper limit temperature. Moreover, since the heat stored in the heat storage body 3 is dissipated to the outside from the part (side part and bottom part) of the container 2 where the electronic component 4 is not attached, all of the heat storage body 3 is melted to a high temperature equal to or higher than a predetermined temperature. Is suppressed. Furthermore, when the heat storage body 3 repeats the phase change from solid to liquid, and the air contained in the heat storage body 3 is exposed in the container 2, the air moves upward and the gap 5 And the gap 5 is enlarged. At this time, the shape (curvature and inclination) of the inner surface 2b, the shape (width and interval) of the convex portion 2c, the amount of the heat storage body 3, etc. Is set. For this reason, the contact state of the heat accumulator 3 with respect to the entire portion 2d of the inner surface 2b of the container 2 and most of the surface of the convex portion 2c is always maintained.

  As described above, by inclining the one inner surface 2b that is the root of the convex portion 2c in the container 2, even if air exists in the container 2, the air moves due to melting of the heat storage body 3 or the like. Since the gap 5 is formed in the non-true back portion 2e without being accumulated in the back portion 2d of the electronic component 4 on the inner surface 2b of the container 2, an air gap is widened between the heat storage body 3 and the electronic component 4. Can be prevented.

  Further, the inner surface 2b on the back side of the one surface 2a of the container 2 in contact with the electronic component 4 is inclined, and a plurality of convex portions 2c are provided on the one inner surface 2b, so that the portion of the container 2 on the electronic component 4 side And the contact area between the heat storage body 3 can be widened.

  Moreover, by making the convex part 2c in the container 2 into a plate shape, even if air exists in the container 2, the air hardly collects around the convex part 2c, and the convex part 2c and the heat storage body 3 It is possible to prevent air gaps between the two.

  In addition, by inclining the inner surface 2b of the container 2 away from the one surface 2a as it goes from the end toward the center, even if air exists in the container 2, the air is an electron on the inner surface 2b. It can guide | invite reliably so that it may accumulate on the edge of the non-true back part 2e of the components 4. FIG. For this reason, it becomes possible to prevent reliably that the space | gap of an air expands and interposes between the thermal storage body 3 and the electronic component 4. FIG.

  Further, by directing the one surface 2a of the container 2 in contact with the electronic component 4 in the direction opposite to the direction of gravity, even when air is present in the container 2, the heat storage body 3 is melted when the heat storage body 3 is melted in the container 2. It can be reliably guided so that the body 3 moves downward by its own weight, and the air moves upward and accumulates in the non-true back portion 2e of the electronic component 4 on the inner surface 2b of the container 2. For this reason, it becomes possible to more reliably prevent the air gap from being spread and interposed between the heat accumulator 3 and the electronic component 4 and around the convex portion 2 c directly behind the electronic component 4.

  Therefore, when the electronic component 4 operates and generates heat, the heat from the electronic component 4 is more efficiently released to the heat storage body 3 from almost the entire surface of each convex portion 2c of the container 2, and the electronic component 4 is heated to a high temperature. It becomes possible to suppress becoming.

  The present invention can adopt various forms other than the embodiment described above. For example, in the above embodiment, the inner surface 2b of the container 2 is inclined in an arc shape, and a plurality of plate-like convex portions 2c are provided on the inner surface 2b. However, the present invention is limited to this. It is not a thing. In addition to this, for example, as shown in FIG. 5, one inner surface 2b is inclined in a substantially hemispherical shape, and a plurality of prismatic projections 2c are provided on the one inner surface 2b. The cylindrical inner surface 2b is provided with a plurality of cylindrical protrusions 2c, or the inner surface 2b is inclined in a quadrangular pyramid shape as shown in FIG. A plurality of portions 2c may be provided. 5 to 7, the same reference numerals are given to the same or corresponding parts as those in FIGS. Even if it does in this way, the contact area of the part by the side of the electronic component 4 of the container 2 and the thermal storage body 3 is widened, preventing that the clearance gap of air expands between the thermal storage body 3 and the electronic component 4. Therefore, it is possible to efficiently release the heat from the electronic component 4 to the heat storage body 3 through the container 2 and to prevent the electronic component 4 from reaching a high temperature. In particular, as shown in FIG. 6 and FIG. 7, by making the convex portion 2 c cylindrical, the fluidity of the heat storage body 3 dissolved in the container 2 is increased, so the molten heat storage body 3 is injected into the container 2. When this is done, air can be easily removed from the container 2. Further, it is possible to reliably prevent the air existing in the container 2 from accumulating around the convex portion 2c, and the air gap between the convex portion 2c and the heat storage body 3 can be reliably prevented, thereby further improving the efficiency. Well, it is possible to prevent the heat generated from the electronic component 4 from escaping from the entire surface of each convex portion 2 c to the heat storage body 3, and the electronic component 4 from becoming high temperature.

  Moreover, in the above embodiment, although the example which the one surface 2a of the container 2 which contact | connects the electronic component 4 faced the direction opposite to the gravity direction was given, this invention is not restricted only to this. In addition to this, for example, one surface 2a of the container 2 in contact with the electronic component 4 has a direction (side) perpendicular to the direction of gravity (downward in FIGS. 8 and 9) as shown in FIGS. It may be oriented, or may be directed in an oblique direction between a direction opposite to the direction of gravity and a direction perpendicular to the direction of gravity. 9 is a cross-sectional view taken along the line CC of FIG. In FIG. 8 and FIG. 9, the same or corresponding parts as those in FIGS. In the above case, when a plurality of plate-like convex portions 2c are provided on the inner surface 2b on the back side of the one surface 2a of the container 2, each convex portion 2c is arranged with respect to the direction of gravity as shown in FIGS. In other words, they may be arranged so as to be arranged at a predetermined interval in a direction that is perpendicular to the planes 2a and 2b (a direction perpendicular to the screen in FIGS. 8 and 9). By doing in this way, even if air exists in the container 2, when the heat storage body 3 is melted, the air moves and accumulates in the non-back part 2e of the electronic component 4 on the inner surface 2b, It can be surely guided so that the air gap 5 is formed in 2e. In particular, since air easily moves upward, as shown in FIG. 8, the air is surely guided so that a large gap 5 is formed by accumulating a large amount of air in the non-true back portion 2e of the electronic component 4 located above. can do. For this reason, it becomes possible to prevent the air gap between the heat storage body 3 and the electronic component 4 so as to be more reliably prevented.

It is sectional drawing of the electronic device which concerns on embodiment of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a perspective view of the principal part of the electronic device which concerns on embodiment of this invention. It is a perspective view of the principal part of the electronic device which concerns on other embodiment of this invention. It is a perspective view of the principal part of the electronic device which concerns on other embodiment of this invention. It is a perspective view of the principal part of the electronic device which concerns on other embodiment of this invention. It is sectional drawing of the electronic device which concerns on other embodiment of this invention. It is CC sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Container 2a One surface 2b One inner surface 2c Convex part 2d The back part of an electronic component 2e The non-back part of an electronic component 3 Heat storage body 4 Electronic component

Claims (5)

An electronic component, a heat storage body, and a thermally conductive container enclosing the heat storage body, wherein one surface of the electronic component is in contact with one surface of the container, and one inner surface on the back side of the one surface of the container In an electronic device provided with a plurality of protrusions,
The electronic apparatus according to claim 1, wherein the inner surface of the container is inclined so that a portion directly behind the electronic component is farther from the surface than a portion not directly behind. The electronic device according to claim 1,
The said convex part is formed in plate shape, The electronic device characterized by the above-mentioned. The electronic device according to claim 1,
The said convex part is formed in the column shape, The electronic device characterized by the above-mentioned. The electronic device according to claim 1,
The electronic device according to claim 1, wherein the inner surface of the container is inclined so as to become farther from the one surface as it goes from the end toward the center. The electronic device according to claim 1,
The electronic device according to claim 1, wherein the one surface of the container is directed in a direction opposite to a gravitational direction.

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