JP6383756B2 - Electronic equipment - Google Patents

Description

  The present invention relates to an electronic device, and more particularly to an electronic device having high heat dissipation performance.

  For example, in an electronic control unit (ECU) that is an electronic device for a vehicle that controls a drive device such as an internal combustion engine, a board on which an electrical component that generates heat, such as a power semiconductor element, is mounted in the housing. It is stored. Since heat generated in a power semiconductor element or the like affects the characteristics of other electrical components, it is required to quickly dissipate heat from the substrate to the outside of the housing.

  As a structure for improving the heat dissipation characteristics of the substrate, a technique is known in which heat dissipation grease having high thermal conductivity is applied to the back surface of the substrate and brought into contact with the housing (see Patent Document 1).

  FIG. 4 is a view showing a cross section of the printed circuit board disclosed in Patent Document 1. As shown in FIG. The printed circuit board 2 includes a conductive pattern 6 made of copper foil or the like and an insulating layer. The printed circuit board 2 is provided on the inner surface of the housing 4 of the electronic device, and an electrical component 3 is mounted on the surface 2a.

  By applying the heat radiation grease 5 to the back surface 2b of the printed circuit board 2, a heat radiation path including the heat generating portion 3a, the front surface 2a, the conductive pattern 6, the conductor 7a, the heat radiation grease 5 and the housing 4 of the electrical component 3 is configured. The heat generated in the multilayer substrate is radiated to the housing 4.

  However, in the heat dissipation structure as described in Patent Document 1, heat is likely to accumulate in the peripheral region of the substrate that is separated from the heat dissipation path, and thus sufficient heat dissipation efficiency cannot always be obtained. Moreover, since the performance of the heat dissipation grease becomes a bottleneck that determines the heat dissipation performance in the heat dissipation path, the use of high-performance heat dissipation grease is indispensable, which may increase the cost.

JP 2014-127522 A

  From such a background, there is a demand for an electronic device having high heat dissipation efficiency that is unlikely to accumulate heat in the substrate.

One embodiment of the present invention is an electronic device including a substrate on which a conductive pattern directly or indirectly connected to an electrical component mounted on a surface is formed, and a housing that houses the substrate. In this electronic device, a protrusion that is a part of the inner surface of the housing is fitted into a recess formed on the side surface of the substrate.
According to another aspect of the invention, the substrate is a multilayer substrate.
According to another aspect of the present invention, the recessed portion has an exposed portion where a part of the conductive pattern is exposed, and the exposed portion is electrically connected to the protruding portion.
According to another aspect of the present invention, the housing includes an upper lid and a lower lid, and the protrusion includes a part of the upper lid and a part of the lower lid.
According to another aspect of the present invention, waterproof grease is provided on the outer surface of the casing, and the waterproof grease is exposed on the outer surface of the casing at a contact surface between a part of the upper lid and a part of the lower lid. Cover the edges to be

It is a figure which shows the structure of the housing | casing of the electronic device which concerns on one Embodiment of this invention. It is a figure which shows the structure of the board | substrate of the electronic device which concerns on one Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on one Embodiment of this invention. It is a figure which shows the electronic device of a prior art.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of an electronic device according to an embodiment of the present invention. The electronic device according to the present embodiment is, for example, an electronic control unit (ECU) mounted on a vehicle. However, the configuration of the electronic device of the present invention is not limited to this, and can be widely applied to general electronic devices. .

  The electronic apparatus 100 includes a housing 101, a substrate 103 (shown by a dotted line) accommodated in the housing 101, and a connector 102 mounted on the substrate 103.

  The housing 101 includes a substrate mounting portion 114 (shaded portion in the figure) on the inner side, and the substrate 103 and the housing 101 are electrically, thermally, and mechanically connected to the substrate mounting portion 114 as will be described later. Connected to.

  2A and 2B are diagrams showing the configuration of the substrate 103. FIG. 2A is a top view (viewed from the same side as the top view shown in FIG. 1), and FIG. FIG. 2A is a partial cross-sectional view of the substrate 103 shown in FIG. 2A, and FIG. 2C is a cross-sectional view of the substrate 103 shown in FIG.

  The substrate 103 is a multilayer printed wiring board (printed substrate) in which three insulating layers 104, 105, and 106 are laminated. Here, the upper surface of the insulating layer 104 shown in FIG. 2C is the front surface (corresponding to the surface shown in FIG. 2A) of the substrate 103 which is a multilayer substrate, and the lower surface of the insulating layer 106 is the multilayer substrate. This is referred to as the back surface of the substrate 103.

  Conductive patterns 108a and 108b (the mesh portions shown in FIG. 3) are formed on the front and back surfaces of the substrate 103, respectively. These conductive patterns 108a and 108b are, for example, ground patterns that are directly or indirectly connected to, for example, three electrical components 107 mounted on the front surface of the substrate 103 to constitute an electronic circuit. The electronic circuit is electrically connected to an external device (for example, an external power supply device) via a connector 102 mounted on the substrate 103. In addition, between the front surface, the back surface, and / or the insulating layers 104, 105, and 106 of the substrate 103, for example, the conductive patterns 108a and 108b, which are ground patterns, for various signals constituting the electronic circuit. Although a conductive pattern or the like may be formed, the illustration is omitted in FIG. 3 in order to simplify the drawing and facilitate understanding.

  In particular, as shown by broken lines in FIG. 2A, the side surfaces of the insulating layer 105, which is the inner layer of the substrate 103, are formed on the upper and lower portions of the insulating layer 105 in FIG. 2C. That is, it is formed on the inner side of the side surface of the two insulating layers 104 and 106 adjacent to each other with the insulating layer 105 interposed therebetween. As a result, the side surfaces of the insulating layers 104 and 106 protrude from the end portions of the insulating layer 105 sandwiched between the insulating layers 104 and 106, respectively, and are recessed spaces 111 that are concave portions formed by the protruding portions and the side surfaces of the insulating layer 105. However, the four sides constituting the periphery of the substrate 103 are continuously formed over three sides excluding the side where the connector 102 is formed.

  In addition, the insulating layer 104 has an exposed portion 110a which is a conductive pattern provided on the lower surface in FIG. 2C (that is, a surface adjacent to the insulating layer 105) and is a portion exposed to the concave space 111. Similarly, the insulating layer 106 has an exposed portion 110b which is a conductive pattern provided on the upper surface in FIG. 2C (ie, a surface adjacent to the insulating layer 105) and is a portion exposed to the concave space 111. . The exposed portions 110 a and 110 b are formed so as to be continuous over the three sides of the substrate 103 along the concave space 111. However, the exposed portions 110a and 110b may be formed on at least a part of the three sides.

  Further, the exposed portions 110a and 110b are connected to the conductive pattern 108a provided on the front surface of the substrate 103 and the conductive pattern 108b provided on the back surface by the via 109a and the via 109b, respectively.

  3A is an SS partial cross-sectional arrow view of the electronic device 100 shown in FIG. 1, and FIG. 3B is a TT partial cross-sectional arrow view of the electronic device 100 shown in FIG.

  The housing 101 includes a housing upper lid 118 and a housing lower lid 119. Each end of the casing upper lid 118 and the casing lower lid 119 (the left side in FIG. 3A) is processed so as to be folded back inward of the casing 101 to form flat plate portions 121a and 121b. A part of the inner surface of the body 101 is formed. Further, the flat portions 121a and 121b come into contact with each other and form a protrusion 117 as a unit. Note that the housing upper lid 118 and the housing lower lid 119 have projections 117 formed of flat plate-like portions 121 a and 121 b, as will be described later, between the protruding portion of the insulating layer 104 and the protruding portion of the insulating layer 106. By being sandwiched and connected between the spaces (that is, the concave space 111), the whole functions as the housing 101.

  Further, the housing upper lid 118 is provided with a concave portion formed in a U-shape in the vicinity of the left end portion in the drawing of FIG. 3A and molded into a concave shape when viewed from the inner surface of the housing upper lid 118. Similarly, the housing lower lid 119 is provided with a concave portion that is processed in a U-shape in the vicinity of the left end of FIG. 3A and is formed in a concave shape when viewed from the inner surface of the housing lower lid 119. Yes. The protrusion 117 composed of the plate-like portions 121a and 121b corresponds to the substrate mounting portion 114 (shown as a hatched line) shown in FIG. 1 and has a concave shape formed on the side surface between the two insulating layers 104 and 106. It fits into the space (that is, the concave space 111 in FIG. 2C). The protrusion 117 is formed so that its thickness is larger than the width of the gap of the concave space 111. As a result, the protrusion 117 is sandwiched in the concave space 111 by the elastic force of the insulating layer 104 and / or the insulating layer 106 adjacent in the vertical direction in the drawing, and the exposed portion 110a formed on the lower surface of the insulating layer 104 in the drawing, And it contacts the exposed portion 110b formed on the upper surface of the insulating layer 106 in the figure. Note that, for example, in the limit where the substrate 103 is substantially mechanically fixed to the housing 101, the thickness of the protrusion 117 is formed to be smaller than the width of the gap of the concave space 111, and the conductive and It is good also as what fills the paste etc. which have heat conductivity.

  Of the two concave portions formed in the vertical direction of the projection 117, the projection of the insulating layer 104 protruding from the side surface of the substrate 103 is fitted in the concave portion on the upper side of the projection 117. The protruding portion of the insulating layer 106 protruding from the side surface of the substrate 103 is fitted into the concave portion on the lower side of the protruding portion 117 in the figure. As described above, if the protrusion 117 is sandwiched in the concave space 111, it is not always necessary to sandwich the protrusions by the two recesses. However, for example, the width of the gap between the recesses is set to the insulating layer 104 and By making the width narrower than the thickness of the insulating layer 106 and generating the elastic force of the casing 101 and / or the plate-like portions 121a and 121b, the projecting portions are sandwiched from above and below in the figure, whereby the casing 101 and the substrate 103 The holding strength can be increased.

  As described above, the protrusion 117 which is the substrate mounting portion 114 mechanically fixes the substrate 103 to the inside of the housing 101. The exposed portions 110 a and 110 b and the insulating layers 104 and 106 of the substrate 103 are thermally connected to the protrusions 117 that are the substrate mounting portions 114 to form a heat dissipation path from the substrate 103 to the housing 101. Further, since the protruding portion 117 is electrically connected to the exposed portions 110a and 110b of the substrate 103, the conductive patterns 108a and 108b and / or the electrical component 107 leading to the exposed portions 110a and 110b are interposed via the protruding portion 117. Thus, the potential of the casing 101 (ground potential) is maintained.

  Note that the substrate 101 and the housing 101 are the sides on which the connector 102 is mounted, of the four sides, as indicated by the formation region (shown in the drawing) of the substrate mounting portion 114 in FIG. Since the three sides are fixed, the two sides are electrically, thermally, and mechanically connected.

  In addition, a groove portion having a triangular cross section with the end portion at the apex is formed at an end portion of the contact surface between the flat plate portions 121a and 121b on the outer surface side of the housing 101, and is waterproof so as to fill the groove portion. Grease 120 is applied. The waterproof grease 120 is applied in the shape of a triangular prism surrounding the casing 101 so as to cover the end of the contact surface between the flat plate-like parts 121a and 121b, so that the applied waterproof grease 120 moves over time. And a stable waterproof effect can be obtained with a small amount of waterproof grease.

  As described above, in the electronic device 100 according to the present embodiment, in addition to the natural heat radiation from the front surface and the back surface of the substrate 103, the concave space 111 is provided on the side surface of the substrate 103 so that the side surface of the substrate 103 is connected to the housing 101. Since a heat radiation path is newly provided so that heat can be radiated from the peripheral region of the substrate and the insulating layer on the inner layer of the substrate, higher heat radiation efficiency can be obtained as compared with the prior art.

  At the same time, the conductive patterns 108 a and 108 b that are ground patterns provided on the substrate 103 are electrically connected to the housing 101 via the exposed portions 110 a and 110 b that are conductive patterns provided so as to be exposed in the concave space 111. Are also connected, and the ground connection of the electronic circuit configured on the substrate 103 is also secured.

  Further, the above-described configuration of the electronic device 100 of the present invention can be realized only by processing a part of the member without using a new member, so that the heat radiation efficiency is high without causing an increase in manufacturing cost. An electronic device can be realized.

  As described above, the electronic device 100 of the present invention includes the substrate 103 on which the conductive pattern 108a or the like connected directly or indirectly to the electrical component 107 mounted on the surface is formed, and the substrate 103 accommodated therein. The protrusion 117 which is a part of the inner surface of the housing 101 is fitted into the concave space 111 formed on the side surface of the substrate 103. Thereby, even in the peripheral portion of the substrate 103, it is difficult to accumulate heat, and the electronic device 100 having high heat dissipation efficiency can be provided at low cost.

  In the electronic device 100 according to the present embodiment, the conductive patterns 108a and 108b exposed to the concave space 111 are ground patterns. However, the present invention is not limited to this, and a conductive pattern that does not constitute an electronic circuit (for example, a heat conduction pattern). It can also be.

  In the electronic device 100 according to the present embodiment, the concave space 111 is formed on the side surfaces of the three sides of the substrate 103, and the substrate 103 and the housing 101 are electrically, thermally, and mechanically formed on the three sides. However, the present invention is not limited to this, and the same effect can be obtained by providing a concave space on at least one side of the substrate 103 and connecting the housing 101 on the at least one side. Can be obtained.

  Further, in this embodiment, a multilayer substrate is used as the substrate 103. However, the present invention is not limited to this. For example, a single-layer printed substrate is used, and the side surface of the single-layer printed substrate is processed to form a recess. What to provide is very good. Further, similarly to the conventional technology, for example, the back surface of the substrate 103 and the housing 101 can be configured to contact each other, and a heat radiating member such as heat radiating grease can be applied to the contacted portion to improve the heat radiation efficiency. In this case, since efficient heat radiation is performed also from the side surface of the substrate 103, sufficient heat radiation efficiency can be obtained with general-purpose heat radiation grease without using high-performance heat radiation grease as in the prior art.

  The present invention is not limited to the above-described embodiments, and can be modified and used without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... Electronic device, 101 ... Housing, 102 ... Connector, 103 ... Substrate, 104, 105, 106 ... Insulating layer, 107 ... Electrical component, 108a, 108b ... Conductive pattern 109a, 109b ... via, 110a, 110b ... exposed part, 111 ... concave space, 114 ... substrate mounting part, 117 ... projection part, 118 ... casing top cover, 119: Lower case lid, 120 ... Waterproof grease, 121a, 121b ... Flat plate part, 2 ... Printed circuit board, 3 ... Electrical component, 4 ... Housing, 5 ...・ Heat radiation grease, 6 ... conductive pattern, 7a ... conductor

Claims (4)

An electronic device comprising: a substrate on which a conductive pattern connected directly or indirectly to an electrical component mounted on a surface is formed; and a housing that accommodates the substrate therein,
A protrusion that is a part of the inner surface of the housing is fitted into the recess formed on the side surface of the substrate ,
The housing is composed of an upper lid and a lower lid,
The protrusion is composed of a part of the upper lid and a part of the lower lid.
Electronic equipment. The electronic device according to claim 1,
The substrate is a multilayer substrate;
Electronic equipment. The electronic device according to claim 1 or 2,
The substrate has an exposed portion in which a part of the conductive pattern is exposed in the recess,
The exposed portion and the protruding portion are electrically connected;
Electronic equipment. The electronic device according to any one of claims 1 to 3 ,
Provided with waterproof grease on the outer surface of the housing,
The waterproof grease covers an end of the contact surface between a part of the upper lid and a part of the lower lid that is exposed on the outer surface of the housing.
Electronic equipment.

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