JP2018067617A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an electronic device including a structure which can inhibit movement of fine particles generated in a housing.SOLUTION: An electronic device (100) includes: a circuit board (105) on which an electric circuit is mounted; and a housing (101) formed by two support mediums (101a, 101b). The circuit board has peripheral edge parts (216a) protruding from at least a part of a side surface. The two support mediums sandwich the peripheral edge parts and fix the circuit board. The circuit board has steps (206a, 206b, 226a, 226b) between itself and a surface of the circuit board on which the electric circuit is mounted and between itself and surfaces of the peripheral edge parts with which the support mediums contact.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic device, and more particularly to an electronic device including a circuit board that is sandwiched and fixed inside a housing.

  In general, in an electronic control unit (ECU) mounted on a vehicle, a circuit board on which a control circuit is mounted is accommodated in a housing. For example, two support bodies (base and cover) constituting the housing are included. ), The circuit board can be fixed in the housing by mechanically sandwiching a part of the circuit board.

  In such a case, for example, the base and the cover constituting the casing can sandwich a material portion (for example, a resin material) constituting the circuit board. The base and the cover are made of metal and are sandwiched so as to be in contact with the ground pattern formed on the circuit board, whereby the ground pattern and the housing can be electrically connected together with fixing the circuit board.

  When the circuit board is sandwiched in such a manner, the metal normally used as the base and cover constituting the housing and the resin material normally used in the circuit board have greatly different linear expansion coefficients. In some cases, relative displacement occurs between the base and the cover and the circuit board due to the fluctuations, and the both may slide.

  Further, if the portion sandwiched between the base and the cover is, for example, a material portion of a circuit board, the material portion is worn by sliding as described above, and the resin material (insulator) constituting the circuit board is worn. Powder may be generated. If such powder enters a circuit contact (for example, a contact between terminals in a connector or the like) to cause a contact failure, there is a possibility of causing an abnormality in the circuit operation.

  Further, even when the portion sandwiched between the base and the cover is a ground pattern portion formed on the circuit board, the metal thin film constituting the ground pattern may be worn by the sliding to generate metal powder. If such a metal powder may cause a short circuit between the wirings of the control circuit, for example, it may cause a serious abnormality in the circuit operation.

JP 2014-197816 A

  From such a background, even when the circuit board is sandwiched between the supports constituting the housing, the powder generated by sliding between the circuit board and the support reaches the surface of the circuit board. Realization of an electronic device having a configuration that can be suppressed is desired.

One embodiment of the present invention is an electronic device including a circuit board and a housing including two supporting bodies. In the electronic device, the circuit board has a peripheral edge protruding from at least a part of a side surface thereof, and the two supporting bodies sandwich the peripheral edge to fix the circuit board. There is a step between the surface of the circuit board and the surface of the peripheral edge where the support comes into contact.
According to another aspect of the invention, the circuit board is a multilayer board, and the peripheral edge is a part of an inner layer of the multilayer board.
According to another aspect of the present invention, the support is in contact with a conductive pattern formed on at least a part of the peripheral edge.
According to another aspect of the invention, the conductive pattern is a ground pattern.
According to another aspect of the present invention, a space defined by a part of the support, the step, and the peripheral edge is provided.
According to another aspect of the present invention, an adhesive material is provided on a part of the inner surface of the space.
According to another aspect of the present invention, an angle formed between the peripheral edge portion and the side surface of the circuit board is a right angle or an acute angle.

It is a figure which shows the structure of the electronic device which concerns on embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on embodiment of this invention. It is a figure which shows the structure of the circuit board mounted in the electronic device which concerns on embodiment of this invention.

  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 100 according to an embodiment of the present invention. The electronic device 100 according to the present embodiment is, for example, an electronic control unit (ECU, Electronic Control Unit) mounted on a vehicle. However, the configuration of the electronic device of the present invention is not limited to this, and widely used in general electronic devices. Can be applied.

  FIG. 1 is a top view of the electronic device 100. The electronic apparatus 100 includes a housing 101, a circuit board 105 (shown by dotted lines) housed in the housing 101, and a connector 102 mounted on the circuit board 105.

  FIG. 2A is an SS cross-sectional arrow view of the electronic device 100 shown in FIG. The housing 101 includes two supports, a cover 101a and a base 101b. The cover 101a and the base 101b are fixed to each other by four screws 103a, 103b, 103c, and 103d to form an internal cavity. The circuit board 105 is accommodated in the internal cavity.

  In particular, the circuit board 105 mounted on the electronic device 100 has a peripheral edge 216a configured such that a part of the circuit board protrudes from the side surface. The cover 101a and the base 101b constituting the housing 101 sandwich the peripheral edge portion 216a in the thickness direction (the vertical direction in FIG. 2A), whereby the circuit board 105 is placed inside the housing 101. Fix it.

  Hereinafter, the configuration of the circuit board 105 will be further described with reference to FIGS. 2 (a), 2 (b), and 3. FIG. 2B is a partial detailed view of the region 230 in FIG. 2A, and FIG. 3 is a perspective view of the circuit board 105. FIG.

  The circuit board 105 is a rectangular flat plate, and is a multilayer board (for example, a multilayer printed wiring board) in which three insulating layers 206, 216, and 226 are stacked. Here, the upper surface of the insulating layer 206 in FIG. 2A is referred to as a front surface of the circuit board 105, and the lower surface of the insulating layer 226 is referred to as a back surface of the circuit board 105. An electrical component (not shown) that constitutes an electronic circuit is mounted on the front surface and / or the back surface of the circuit board 105, and the electronic circuit is connected to an external device (via an connector 102 mounted on the circuit board 105). For example, it is electrically connected to an external power supply device or the like, and power is supplied from the power supply or the like, or information is transmitted between other devices (not shown).

  In addition to the conductive patterns 207, 217, 227, and 237, various conductive patterns for signals may be formed between the front surface, the back surface, and / or the insulating layers 206, 216, and 226 of the circuit board 105. However, in order to simplify the drawing and facilitate understanding, the illustration thereof is omitted in FIGS. 2 (a), 2 (b) and FIG.

  As shown in FIG. 2A, the circuit board 105 includes an insulating layer 216 that is an inner layer, an insulating layer 206 formed adjacent to the upper side of the insulating layer 216 in the figure, and the insulating layer 216. The length in the left-right direction is longer than the insulating layer 226 formed adjacent to the lower side in the figure. As a result, the insulating layer 216 that is the inner layer protrudes from the left and right side surfaces of the insulating layers 206 and 226 in the drawing, and constitutes a peripheral edge portion 216a that protrudes from the left and right side surfaces of the circuit board 105 in the drawing.

  As shown in FIG. 3, the peripheral edge portion 216 a is formed to be continuous along three side surfaces of the four side surfaces of the circuit board 105 except the side surface on which the connector 102 is mounted. .

  Further, a conductive pattern 208a (for example, a ground pattern) is formed along the peripheral edge 216a on the front surface side of the peripheral edge 216a, and the conductive pattern 208a is also formed on the front surface side of the peripheral edge 216a. The conductive pattern 217 formed between the insulating layer 206 and the insulating layer 216 is electrically connected through the formed connection portions 317a and 317b.

  Further, a conductive pattern 208b (for example, a ground pattern) is formed on the back surface side of the peripheral edge portion 216a at a position facing the conductive pattern 208a on the front surface side, and the conductive pattern 208b is, for example, an insulating layer A part of the control circuit is configured by being electrically connected to a conductive pattern 227 and the like formed between 216 and the insulating layer 226.

  Further, a part of the inner surface of the cover 101a and a part of the inner surface of the base 101b are in contact with each of the conductive patterns 208a and 208b formed on the front surface side and the back surface side of the peripheral edge 216a of the circuit board 105. Arranged. Then, the screws 103a, 103b, 103c, and 103d (FIG. 1) for fixing the cover 101a and the base 101b are fastened, so that the conductive patterns 208a and 208b are brought into contact with the cover 101a and the base 101b. 2A is pressed in the illustrated vertical direction (that is, the thickness direction of the circuit board 105), and the peripheral portion 216a is sandwiched in the thickness direction, whereby the circuit board 105 is fixed.

  The conductive patterns 208a and 208b formed on the front surface side and the back surface side of the peripheral edge 216a with which the cover 101a and the base 101b abut are used as ground patterns, for example, and the casing 101 (that is, the cover 101a and the base 101b). ) Is a conductive material such as metal (for example, aluminum), the ground line of the electronic circuit configured on the circuit board 105 is provided outside the electronic device 100 via the housing 101. Can be connected to the ground line of the power supply.

  Here, in general, when the circuit board is sandwiched and fixed by two supports constituting the casing, for example, when the environmental temperature repeatedly fluctuates, the linear expansion coefficient of the material constituting the support and the circuit board Due to this difference, a relative positional shift occurs between the support and the circuit board, and both slide. When such sliding occurs, the support and the material portion or the conductive pattern of the circuit board sandwiched by the support are rubbed together, and the surface of the material portion or the conductive pattern is worn away. Resin powder derived from the constituent resin material or metal powder derived from the metal constituting the conductive pattern may be generated. Such resin powder or metal powder may enter a circuit contact or the like to cause a contact failure or short circuit between wirings, thereby causing an abnormality in circuit operation.

  Also in the electronic apparatus 100, metal powder derived from the metal material of the conductive patterns 208a and 208b can be generated from the contact area between the cover 101a and the base 101b and the conductive patterns 208a and 208b. However, the circuit board 105 mounted on the electronic device 100 includes the peripheral portion 216a and the insulating layers 206 and 226 in the vicinity of the contact area between the cover 101a and the base 101b and the conductive patterns 208a and 208b. Steps 206a, 206b, 226a, and 226b are provided, and movement of the metal powder in the housing can be suppressed by the steps. FIG. 2 is a partial detail view of a region 230 (FIG. 2A) including a step 206 a among the steps provided at four positions of the circuit board 105 with respect to the configuration in which the powder can be prevented from moving by the step. This will be described with reference to 2 (b).

  The portion where the cover 101a and the conductive pattern 208a abut is located below the surface of the insulating layer 206 constituting the front surface of the circuit board 105 by the thickness of the insulating layer 206 and the conductive pattern 217. A step 206 a is provided between the contact portion and the front surface of the circuit board 105. The step 206a serves as a barrier against the movement of the metal powder, prevents direct movement of the metal powder to the front surface of the circuit board 105, and prevents the metal powder generated from the contact portion. Most of the metal powder is adhered or deposited on the surface of the step 206a and / or the peripheral edge portion 216a, thereby preventing re-scattering of the metal powder. Thereby, the amount of the metal powder that reaches the front surface of the circuit board 105 can be greatly reduced.

  Further, in the electronic device 100 of this embodiment, the gap formed between the upper end of the insulating layer 206 in the drawing and the inner surface 201a of the cover 101a is made as narrow as possible, so that the inner surface 201a of the cover 101a and the peripheral portion A space 220 constituted by the upper surface of 216a in the drawing and the step 206a is formed. As a result, most of the metal powder generated from the contact portion stays in the space 220, and finally forms the inner surface 201a of the cover 101a and the step 206a constituting the inner surface of the space 220. Since it is captured by any one of the side surface of the circuit board 105 and the upper surface of the peripheral portion 216a in the figure, the metal powder moving to the front surface of the circuit board 105 can be effectively reduced.

  Although only the region 230 shown in FIG. 2A has been described here, the steps 206b, 226a, and 226b are also included in the region including the other steps 206b, 226a, and 226b. Thus, it is possible to suppress the metal powder that can be generated from the conductive patterns 280a and 280b from reaching the front and back surfaces of the circuit board 105.

  As described above, the electronic device 100 according to the present embodiment includes the circuit board 105 on which the electric circuit is mounted and the housing 101 including the two supports (101a and 101b). The circuit board 105 has a peripheral edge 216a protruding from at least a part of its side surface, and the circuit board 105 is sandwiched between the two supports (101a, 101b). The circuit board 105 is fixed between the surface of the circuit board 105 on which the electric circuit is mounted and the surface of the peripheral edge 216a with which the support (101a, 101b) abuts. There is a step 206a constituted by the side surface. As a result, the powder generated from the portion where the two supports (101a, 101b) and the peripheral edge portion 216a contact each other is prevented from reaching the front side and / or the back side of the circuit board 105, and the control circuit malfunctions. Can be prevented.

  Further, in the circuit board 105 of the electronic device 100, only the peripheral edge portion 216a that is a part of the insulating layer 116 constituting the inner layer of the circuit board 105 is sandwiched between the supports 101a and 101b. Compared with the case where the entire circuit board 105 is sandwiched in the thickness direction, the circuit board 105, the cover 101a, and the base can be reduced because the circuit board 105 can be reduced in contraction and expansion due to temperature changes. The stress generated in the contact area with 101b can be substantially reduced. Further, in the electronic device 100, the central part of the circuit board 105 (for example, the front side of the insulating layer 206 and the back side of the insulating layer 226) constituting the main part of the control circuit mounted on the circuit board 105 is Since the cover 101a and the base 101b, which are two supports, are not directly sandwiched by the support 101, damage to the control circuit due to direct stress from the support can be avoided. Can improve the environmental resistance performance.

  In the present embodiment, the conductive patterns 208a and 208b are ground patterns. However, the present invention is not limited to this, and for example, a conductive pattern that does not constitute an electronic circuit (for example, a pattern for heat conduction) may be used. it can.

  Further, a soft metal plate such as a copper plate can be interposed between the conductive patterns 208a and 208b and the support that holds them. As a result, the cover 101a and the base 101b are configured to be in pressure contact with the metal plate. For example, even if the circuit board 105 or the housing 101 is displaced due to a change in environmental temperature, the metal plate is deformed. And since the said displacement is absorbed, sliding of members can be suppressed substantially and generation | occurrence | production of powder can be reduced. Note that if the thickness of the metal plate is, for example, equal to or greater than the thickness of one insulating layer constituting the circuit board, the displacement of the circuit board 105 and the casing 101 can be effectively absorbed. Further, the present invention is not limited to the case where the metal plate is disposed on the conductive patterns 208a and 208b. For example, even when the conductive patterns 208a and 208b are thickened, a certain displacement absorbing effect is obtained, Generation can be reduced.

  Further, a configuration in which the conductive patterns 208a and 208b are not provided in a portion on the peripheral edge 216a where the cover 101a and the base 101b as two supports come into contact, that is, a material portion (for example, a resin material) constituting the peripheral edge 216a. The cover 101a and the base 101b may be directly sandwiched. Thereby, even when powder of the resin material (insulator) constituting the circuit board 105 is generated from the contact portion between the cover 101a and the base 101b and the material portion of the peripheral edge portion 216a, the step 206a and / or the step 206a and / or Since the resin material powder can be captured in the space 220, the resin material powder is effectively prevented from reaching the front and back surfaces of the circuit board 105, for example, in the connector 102. Contact failure caused by the powder can be prevented in advance.

  In the present embodiment, the peripheral edge portion 216a is formed so as to be continuous over three side surfaces excluding the side surface on which the connector 102 is mounted. However, the present invention is not limited to this. The part 216a can be separated into three peripheral parts. Furthermore, the peripheral portion 216a only needs to be formed on any one of the side surfaces constituting the circuit board 105, and as long as the peripheral portion is sandwiched between the supports constituting the housing, the sandwiching portion The effect which prevents the movement of the powder which generate | occur | produces in can be acquired.

  Furthermore, in this embodiment, the four steps 206a, 206b, 226a, and 226b constituted by the peripheral portion 216a and the insulating layers 206 and 226 are provided. However, the present invention is not limited to this, and any one step is provided on the circuit board. If it is formed in 105, a certain effect can be obtained in suppressing the movement of the powder. Further, for example, when an electric circuit is not formed on the back surface of the circuit board 105, the steps 226a and 226b may not be provided. In this case, by projecting the side surface of the lower insulating layer 226 of the circuit board 105 to the same extent as the side surface of the inner insulating layer 216, the peripheral edge portion 216a is formed into the inner insulating layer 216 and the lower insulating layer. 226 can be composed of two insulating layers.

  Further, an adhesive material (for example, an adhesive tape or an adhesive paint) is applied to a part of the step 206a, a part on the front side and / or the back side of the peripheral part 216a, and a part of the inner surface of the cover 101a and the base 101b. By providing, the powder generated in the housing can be fixed to the adhesive. Thereby, the dispersion of powder can be effectively suppressed, and further, the wiring and electrical components mounted on the circuit board 105 can be protected from contamination by powder.

  Further, in the circuit board 105 of the present embodiment, as shown in FIG. 2A, the side surfaces of the insulating layers 206 and 226 (surfaces forming the steps 206a, 206b, 226a, and 226b) and the upper surface of the peripheral portion 216a in the drawing. The angle formed by the lower surface and the lower surface is a right angle, but the angle may be set to an acute angle. With such a configuration, the powder is easily captured at the acute angle portion constituted by the side surface of the insulating layer and the upper surface and the lower surface of the peripheral portion 216a. The electrical component can be more effectively protected from contamination by powder.

  In the present embodiment, a multilayer board is used as the circuit board 105. However, the present invention is not limited to this. For example, a single-layer printed board is used. What provides the peripheral part 216a is very good.

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

  DESCRIPTION OF SYMBOLS 100 ... Electronic device, 101 ... Housing, 101a ... Cover, 101b ... Base, 102 ... Connector, 103a, 103b, 103c, 103d ... Screw, 105 ... Circuit board 206, 216, 226... Insulating layer, 206a, 206b, 226a, 226b... Step, 207, 217, 227, 237, 208a, 208b... Conductive pattern, 216a. ..Space, 317a, 317b ... connection part.

Claims (7)

An electronic device comprising a circuit board and a housing composed of two supports,
The circuit board has a peripheral edge protruding from at least a part of its side surface,
The two support bodies sandwich the peripheral portion to fix the circuit board,
The circuit board has a step between the surface of the circuit board and the surface of the peripheral edge with which the support comes into contact.
Electronic equipment. The circuit board is a multilayer board, and the peripheral edge is a part of an inner layer of the multilayer board.
The electronic device according to claim 1. The support is in contact with a conductive pattern formed on a surface of the peripheral edge;
The electronic device according to claim 1. The conductive pattern is a ground pattern;
The electronic device according to claim 3. A space delimited by a part of the support, the step, and the peripheral portion;
The electronic device according to claim 1. An adhesive material is provided on a part of the inner surface of the space.
The electronic device according to claim 5. An angle formed by the peripheral edge portion and the side surface of the circuit board is a right angle or an acute angle.
The electronic device according to claim 5 or 6.

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