JP2018133472A - Electronic circuit module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic circuit module capable of exhibiting a shielding effect without increasing the number of parts and preventing contact of a shielded electronic circuit with a finger of a worker or a foreign object.SOLUTION: An electronic circuit module 10 includes a circuit board 20 provided with an electronic circuit 22 and a metal cover 30 surrounding the electronic circuit. The metal cover includes a frame-shaped side wall portion 32 that surrounds the entire periphery of the side of the electronic circuit and a top plate part 35 covering the electronic circuit from above. The side wall portion includes a flange portion 31 extending from the bottom to the outside over the entire circumference, and the circuit board and the metal cover are fixed to each other by a metal bonding agent 40 attached to the flange portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-vehicle electronic circuit module, for example, an electronic circuit module used by being mounted on a glass surface of a pillar interior or a window portion.

  The in-vehicle electronic device described in Patent Document 1 includes a circuit board having an electronic circuit and a frame-shaped shield case that electromagnetically shields the electronic circuit, and the shield case is subjected to a reflow process with respect to the circuit board. Soldered. Further, a case having a substantially rectangular parallelepiped shape in which the upper case and the lower case are combined is provided, and the circuit board and the shield case are assembled in the upper case and stored in the case.

JP 2014-156180 A

  In the in-vehicle electronic device described in Patent Document 1, the above-described components are used so that the operator's finger or foreign matter does not touch the circuit board or the shield case in the step after the reflow process for fixing the shield case to the circuit board. It was necessary to store in the case. For this reason, there is a problem that the number of parts increases and the assembly process increases. Further, since the circuit board and the shield case are housed in the case, it has been difficult to perform the board inspection and the application of the moisture-proof coating agent, which should be performed after the reflow process.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic circuit module that can exhibit a shielding effect without increasing the number of components and can prevent an operator's finger or a foreign object from coming into contact with a shielded electronic circuit. Another object of the present invention is to provide an electronic circuit module that can easily perform substrate inspection and application of a moisture-proof coating agent.

  In order to solve the above problems, an electronic circuit module of the present invention includes a circuit board provided with an electronic circuit and a metal cover surrounding the electronic circuit, and the metal cover surrounds the entire circumference of the side of the electronic circuit. A frame-shaped side wall portion and a top plate portion that covers the electronic circuit from above are provided. The side wall portion includes a flange portion that extends outward from the lower portion over the entire circumference, and is attached to the flange portion. The circuit board and the metal cover are fixed to each other by the metal bonding agent.

  As a result, since the electronic circuit is covered from the side and from above, a shielding effect can be obtained by one metal cover without increasing the number of parts. Contact with an electronic circuit can be prevented. By providing the top plate portion and adsorbing it, the assembly by the automatic machine becomes easy and the production efficiency can be increased.

In the electronic circuit module of the present invention, it is preferable that the metal bonding agent is attached to at least the front end surface of the flange portion.
As a result, the metal bonding agent can be easily attached to the circuit board and the metal cover, and by solidifying this, the shielding and watertightness of the internal space of the circuit board and the metal cover can be reliably obtained. Can do. For this reason, the moisture-proof coating agent can be injected into the internal space, whereby the electronic circuit can exhibit stable operation even if it is installed in a vehicle where condensation is likely to occur. Even when solder is used as the metal bonding agent, since the moisture-proof coating agent can be injected after the solder is solidified in a high-temperature reflow process, it is possible to prevent alteration of the moisture-proof coating agent due to heat. Furthermore, since it has water tightness, various moisture-proof coating agents can be used as the moisture-proof coating agent, and liquid-type coating agents can also be used. In addition, when a moisture-proof coating agent is injected into the internal space, it does not leak to the outside, so that appearance defects can be prevented, and the moisture-proof coating agent does not wrap around the back side of the circuit board. There is no inconvenience in mounting parts in the process.

In the electronic circuit module of the present invention, the top plate portion is preferably supported by a plurality of support arm portions extending from the upper portion of the side wall portion.
Thereby, since a top plate part can be reliably hold | maintained with a desired attitude | position, assembly property can be improved.

In the electronic circuit module of the present invention, a plurality of openings leading to the electronic circuit are respectively formed between the plurality of support arms, and the top plate is supported at a position lower than the upper portion of the side wall. It is preferably supported by the arms.
As a result, the opening that leads to the electronic circuit from the outside is in an obliquely opened state, so that the opening area can be increased, so that a wide range inside the internal space of the circuit board and the metal cover can be easily seen. Is possible. Accordingly, it is possible to easily execute processing such as inspection after the metal cover is fixed and application of a moisture-proof coat. Further, the height of the top plate can be used as a guide for the amount of injection when the moisture-proof coating agent is injected into the internal space of the circuit board and the metal cover.

In the electronic circuit module of the present invention, it is preferable that the top plate portion is formed so that at least the upper surface is a flat surface, and is arranged at substantially the center of the side wall portion in plan view.
Thereby, since it becomes easy to attract | suck a top-plate part, holding | maintenance of a metal cover becomes easy and, thereby, the assembly property of an electronic circuit module improves.

In the electronic circuit module of the present invention, the metal cover is preferably formed by drawing.
Thereby, the metal cover provided with the flange part can be manufactured at low cost, and the fixing to the circuit board can be ensured by attaching the metal bonding agent to the flange part.

  According to the present invention, it is possible to exhibit a shielding effect without increasing the number of components, and it is possible to prevent an operator's finger or a foreign object from coming into contact with a shielded electronic circuit.

It is a perspective view which shows the structure of the electronic circuit module which concerns on embodiment of this invention. It is a disassembled perspective view of the electronic circuit module shown in FIG. It is a top view which shows the structure of the metal cover in embodiment of this invention. It is a bottom view of the metal cover shown in FIG. It is a side view of the metal cover shown in FIG. FIG. 6 is a cross-sectional view taken along line VI-VI ′ of FIG. 1. It is the side view to which a part of electronic circuit module concerning the embodiment of the present invention was expanded.

Hereinafter, an electronic circuit module according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a configuration of an electronic circuit module 10 according to the present embodiment, and FIG. 2 is an exploded perspective view of the electronic circuit module 10 shown in FIG. In each figure, XYZ coordinates are shown as reference coordinates. The Z direction is the vertical direction, and the XY plane is a plane orthogonal to the Z direction. In the following description, a state in which the lower side is viewed from the upper side in the Z direction may be referred to as a plan view. In FIG. 2, illustration of the solder 40 is omitted.

  As shown in FIGS. 1 and 2, the electronic circuit module 10 includes a circuit board 20 and a metal cover 30 fixed on the circuit board 20, and is disposed inside a pillar of the vehicle.

  In the circuit board 20, an electronic circuit 22 is provided in a mounting region 21 a in the center of the mounting surface 21 that is the upper surface thereof. Here, in FIG. 2, a plurality of elements constituting the electronic circuit 22 are shown in a simplified manner, and wirings / electrodes, etc. are omitted, but types, shapes, numbers, arrangements, etc. of elements / wirings / electrodes are It can be arbitrarily set according to the specifications of the electronic circuit 22.

  3 is a plan view showing the configuration of the metal cover 30, FIG. 4 is a bottom view of the metal cover 30 shown in FIG. 3, and FIG. 5 is a side view of the metal cover 30. 6 is a cross-sectional view taken along the line VI-VI 'of FIG. FIG. 7 is an enlarged side view of a part of the electronic circuit module 10.

  The metal cover 30 is produced by drawing a metal material into a predetermined shape, and is formed between the mounting surface 21 and the mounting surface 21 when fixed on the mounting surface 21 of the circuit board 20 as shown in FIG. All the electronic circuits 22 in the mounting area 21a are stored in the internal space S. The circuit board 20 and the metal cover 30 are fixed to each other by the solder 40, whereby the electronic circuit 22 in the internal space is electromagnetically shielded from the outside, and the internal space S is in a watertight (liquid tight) state.

  As shown in FIGS. 3 and 4, the metal cover 30 has a substantially rectangular outer shape in plan view, and an outer edge portion of the metal cover 30 is a flange portion 31 having a substantially rectangular frame shape. A side wall 32 rises upward from the inner portion of the flange portion 31 in the Z direction. The side wall portion 32 is formed so as to have a substantially rectangular shape in a plan view like the flange portion 31, and four support arm portions 34a are formed inward from the central portions of the upper portions 33a, 33b, 33c, and 33d of the four sides. , 34b, 34c, 34d extend. Two of these support arm portions 34a and 34c are arranged along the Y direction, respectively, and the remaining two support arm portions 34b and 34d are arranged along the X direction, respectively. These support arm portions 34a, 34b, 34c, and 34d are integrated with the top plate portion 35 so as to support the disc-shaped top plate portion 35 disposed in the center of the metal cover 30 in a plan view. Has been.

  As shown in FIG. 6, the top plate portion 35 is located between the mounting surface 21 of the circuit board 20 and the upper portions 33 a, 33 b, 33 c, and 33 d in the Z direction and does not contact the electronic circuit 22. Placed in position. The top plate portion 35 has a flat plate shape having a flat upper surface 35 b and is arranged in parallel with the mounting surface 21 of the circuit board 20.

  Here, the number of support arm portions is not limited to four, and may be three, or five or more, for example. Further, the position of the support arm portion is not limited to the center position of each of the upper portions 33a, 33b, 33c, and 33d of the side wall portion 32 that forms four sides in a plan view. You may arrange | position along 32 diagonal lines of 32.

  Between the two adjacent support arm portions 34a and 34b, an opening portion 36a penetrating the metal cover 30 in the Z direction is formed. Similarly, an opening portion 36b is formed in the two support arm portions 34b and 34c, The two support arm portions 34c and 34d are formed with openings 36c, and the two support arm portions 34d and 34a are formed with openings 36d.

  The metal cover 30 is formed by drawing a single metal plate. This metal plate is a plate material having a substantially rectangular shape in plan view, and four openings 36a, 36b, 36c, and 36d are formed in the approximate center of the two diagonal lines. While pressing the flange portion 31 with a die while pushing the portion inside the flange portion 31 with the first punch, the side wall portion 32, the support arm portions 34a, 34b, 34c, 34d, and the top plate The top part 35 is formed in a state in which the part 35 is recessed from the flange part 31 and is pushed with a second punch having a smaller diameter than the first punch, so that the top plate part 35 has an upper part 33a of the side wall part 32, The shape is such that it is arranged at a lower position on the flange 31 side than 33b, 33c, 33d. By such a process, a frame-like side wall portion 32 surrounding the entire circumference of the side of the electronic circuit 22 and a top plate portion 35 covering the electronic circuit 22 from above are formed. Is formed with a continuous flange portion 31 extending outward over the entire circumference.

  As shown in FIGS. 1, 6, and 7, solder 40 as a metal bonding agent is attached to the front end surface 31 a (FIG. 7) of the flange portion 31 on the mounting surface 21 of the circuit board 20. The circuit board 20 and the metal cover 30 are coupled to each other by the solder 40.

  The metal cover 30 before being joined is sucked and held by the top plate 35 by an automatic machine, and is disposed on a predetermined position on the mounting surface 21 of the circuit board 20. In a state where the metal cover 30 is disposed on the mounting surface 21 of the circuit board 20, solder paste is attached to a region extending from the mounting surface 21 to the front end surface 31 a of the flange portion 31. For example, the solder paste is applied to the mounting surface 21 by a printing process before the metal cover 30 is installed. Alternatively, after the metal cover 30 is installed on the mounting surface 21, a solder paste is applied to the boundary portion between the front end surface 31 a of the flange portion 31 and the mounting surface 21. When the electronic circuit module in this state is placed in a reflow furnace and heated, the solder paste is melted and then cooled, and then the circuit board 20 and the metal cover 30 are coupled to each other by the solder 40.

  The solder (solder fillet) 40 is attached to at least the front end surface 31a of the flange portion 31 and the mounting surface 21. If the shielding property and water tightness of the internal space S surrounded by the mounting surface 21 and the metal cover 30 can be secured, the solder 40 is mounted. You may adhere also between the surface 21 and the bottom face 31b (FIG. 7) of the flange part 31. FIG. In addition, as the metal bonding agent, a bonding agent other than solder, for example, an adhesive having conductivity and hydrophobicity can be used.

  Furthermore, as shown in FIG. 6, the moisture-proof coating agent 50 is filled up to the height position of the line L in the internal space S so as to cover the electronic circuit 22. The moisture-proof coating agent 50 is injected into the internal space S through the openings 36a, 36b, 36c, and 36d after the circuit board 20 and the metal cover 30 are joined. The height position of the line L is preferably lower than the bottom surface 35a of the top plate portion 35, but may be the same position as the bottom surface 35a or the top surface 35b of the top plate portion 35. Furthermore, the height position of the line L can be a position between the top plate portion 35 and the upper portions 33a, 33b, 33c, 33d of the side wall portion 32. At this time, the top plate portion 35 is moisture-proof coated. Covered with agent 50.

With the configuration described above, the following effects are achieved according to the above embodiment.
(1) The metal cover 30 surrounds the entire periphery of the side of the electronic circuit 22 with a side wall portion 32 and covers the top with a top plate portion 35 and four support arm portions 34a, 34b, 34c, and 34d. For this reason, the shielding effect can be obtained by one metal cover 30 without increasing the number. Furthermore, since the electronic circuit 22 is covered with the metal cover 30, it is possible to prevent an operator's finger or a foreign object from coming into contact with the electronic circuit in a process after manufacturing the electronic circuit module 10. Further, by adsorbing the top plate portion 35, assembly by an automatic machine is facilitated, and manufacturing efficiency can be increased.

(2) Since the solder 40 as the metal bonding agent is attached to the front end surface 31a of the flange portion 31 and the mounting surface 21 of the circuit board 20, the solder 40 can be easily fixed to the circuit board 20 and the metal cover 30. It will be stable. Thereby, the shielding performance and watertightness of the internal space S of the circuit board 20 and the metal cover 30 can be reliably obtained. Due to this airtightness, the moisture-proof coating agent can be injected into the internal space S. Therefore, even when the electronic circuit module 10 is installed in a vehicle where condensation is likely to occur, the electronic circuit 22 can exhibit a stable operation. In addition, since the moisture-proof coating agent can be injected after the solder 40 is solidified through a high-temperature reflow process, it is possible to prevent the moisture-proof coating agent from being altered by heat. Furthermore, since the internal space S has water-tightness, various moisture-proof coating agents can be used as the moisture-proof coating agent, and liquid ones can also be used. Furthermore, since the moisture-proof coating agent does not leak outside when the moisture-proof coating agent is injected into the internal space S, it is possible to prevent the appearance failure and the moisture-proof coating agent does not wrap around the back side of the circuit board 20. In this way, there is no inconvenience in mounting the components in the subsequent process.

(3) Since the top plate portion 35 is supported by the four support arm portions 34a, 34b, 34c, and 34d in the center of the metal cover 30, the top plate portion 35 is in a desired posture, that is, a mounting surface. Since it can hold | maintain reliably with the attitude | position parallel to 21, assembly property can be improved.

(4) The top plate portion 35 is supported by the support arm portions 34a, 34b, 34c, 34d so that the top plate portion 35 is located at a position lower than the upper portions 33a, 33b, 33c, 33d of the side wall portion 32. Openings 36a, 36b, 36c, and 36d are provided therebetween. As a result, the openings 36 a, 36 b, 36 c, 36 d communicating with the electronic circuit 22 from the outside are in an obliquely open state, so that the opening area can be increased, and thereby the circuit board 20 and the metal cover 30 A wide range inside the internal space S can be easily seen. Therefore, it is possible to easily execute processing such as inspection after the metal cover 30 is fixed and application of a moisture-proof coat. Moreover, since the height of the top plate portion 35 can be used as a guide for the injection amount when the moisture-proof coating agent is injected into the internal space S of the circuit board 20 and the metal cover 30, the moisture-proof coating agent can be easily injected. Can do.

(4) Since the top plate portion 35 is arranged at the approximate center of the side wall portion 32 and the top surface 35b of the top plate portion 35 is formed as a flat surface, the top plate portion 35 can be easily sucked. Can be easily held, and as a result, the assembly of the electronic circuit module 10 is improved.

(5) By forming the metal cover 30 by drawing, the metal cover 30 provided with the flange portion 31 can be manufactured at low cost, and by fixing the solder 40 to the flange portion 31, the metal cover 30 can be fixed to the circuit board 20. Can be sure.
Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and can be improved or changed within the scope of the purpose of the improvement or the idea of the present invention.

  As described above, the electronic circuit module according to the present invention is useful in that it can exhibit a shielding effect without increasing the number of parts and can prevent an operator's finger or foreign matter from coming into contact with the shielded electronic circuit. It is.

10 Electronic circuit module 20 Circuit board 21 Mounting surface (upper surface)
21a Mounting area 22 Electronic circuit 30 Metal cover 31 Flange portion 31a Tip surface 31b Bottom surface 32 Side wall portions 33a, 33b, 33c, 33d Upper portion 34a, 34b, 34c, 34d Support arm portion 35 Top plate portion 35a Bottom surface 35b Upper surface 36a, 36b, 36c, 36d Opening 40 Solder S Internal space

Claims (6)

A circuit board provided with an electronic circuit, and a metal cover surrounding the electronic circuit,
The metal cover is
A frame-like side wall surrounding the entire circumference of the side of the electronic circuit;
A top plate that covers the electronic circuit from above;
The side wall portion includes a flange portion extending outward from the lower portion over the entire circumference thereof,
The electronic circuit module, wherein the circuit board and the metal cover are fixed to each other by a metal bonding agent attached to the flange portion.   The electronic circuit module according to claim 1, wherein the metal bonding agent is attached to at least a front end surface of the flange portion.   The electronic circuit module according to claim 1, wherein the top plate portion is supported by a plurality of support arm portions extending from an upper portion of the side wall portion. Between the plurality of support arms, a plurality of openings leading to the electronic circuit are formed, respectively.
The electronic circuit module according to claim 3, wherein the top plate portion is supported by the plurality of support arm portions at a position lower than an upper portion of the side wall portion.   5. The electronic circuit module according to claim 1, wherein at least a top surface of the top plate portion is formed as a flat surface, and the top plate portion is disposed at a substantially center of the side wall portion in a plan view. .   The electronic circuit module according to claim 1, wherein the metal cover is formed by drawing.

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