JP5778501B2 - Board connection structure and flexible printed board mounting structure - Google Patents

Description

  The present invention relates to a board connecting structure for connecting a flexible printed board to a circuit board, and a flexible printed board mounting structure used for the board connecting structure.

  Conventionally, a flexible printed circuit board (hereinafter referred to as FPC) has been widely used as a wiring connected to an electronic circuit board (hereinafter referred to as circuit board) mounted on an automobile or the like. As a method for attaching the FPC to the circuit board, there are a connector type attachment method and a screw attachment method.

  As a connector-type attachment method, a technique is known in which a terminal having a spring structure is provided in a connector attached to a circuit board, and the tip of the FPC is urged in the connector by the spring structure of the terminal. In this technique, the FPC can be attached to the circuit board by the biasing force of the spring structure of the terminal, and there is no need for a soldering process or the like.

  On the other hand, as a screw mounting method, a technique is known in which an FPC having a conductor pattern formed with a bent portion that is bent to the opposite side of a circuit board and the circuit board are fixed with screws (for example, see Patent Document 1). . In this technique, the connection strength between the circuit board and the FPC is ensured by dissolving solder between the copper foil body and the bent portion of the circuit board.

JP 2002-94231 A (pages 2 to 4 and FIG. 3)

  However, in the conventional connector type mounting method described above, since the FPC is attached to the circuit board only by the urging force of the spring structure of the terminal, it cannot be said that the connection strength between the circuit board and the FPC is high, and it is still improved. There was room.

  On the other hand, the conventional screw mounting method has a higher connection strength between the circuit board and the FPC than the connector type mounting method, but requires a soldering step. For this reason, there existed a problem that manufacture was complicated and manufacturing cost became high.

  Therefore, the present invention aims to reduce the manufacturing cost, and can surely improve the bonding strength with the circuit board on the other side, and the mounting structure of the flexible printed circuit board used in this board connection structure The purpose is to provide.

In order to solve the above-described problems, the present invention has the following features. First, a first feature of the present invention is a flexible printed circuit board having a circuit board (circuit board 100) having a connection part (connection part 101) capable of conduction and an attachment part (attachment part 201) attached to the connection part. (FPC 200), and a board connection structure (board connection structure 1) for connecting the flexible printed board to the circuit board, wherein the flexible printed board has an insulating board (board 210), and the board. And a base film (base film 220) on which a conductor pattern (conductor pattern 221) connected to the connection portion is formed, and the substrate is disposed at a position corresponding to the attachment portion of the base film. to form a space (space S) air is sealed between the substrate protrudes toward the opposite side of, with respect to the projecting direction Position can protrusions (protruding portions 222) to increase the is provided.

  According to such a feature, the projecting portion projects toward the opposite side of the substrate to form a space with the substrate and can be displaced with respect to the projecting direction. As a result, when the mounting portion of the flexible printed circuit board is attached to the connection portion of the circuit board, the protruding portion urges toward the connection portion of the circuit board, so that the bonding strength between the flexible printed circuit board and the circuit board is ensured. Can be improved.

  For example, when the board connection structure of the present invention is used in a connector-type mounting method, the protruding portion faces the inner surface of the housing of the connector facing the biasing force of the spring structure of a terminal having a spring structure provided in the connector. Since the terminal is biased, the bonding strength between the flexible printed circuit board and the circuit board can be reliably improved.

  On the other hand, when the board connection structure of the present invention is used in the screw mounting method, the protruding portion urges the copper foil body toward the circuit board in a state where the flexible printed board and the circuit board are fixed by screws. For this reason, the bonding strength between the flexible printed circuit board and the circuit board can be improved without performing soldering or the like.

  As described above, since the bonding strength between the flexible printed circuit board and the circuit board can be improved only by providing the protruding portion at a position corresponding to the mounting portion of the base film, a process for performing soldering or the like is not necessary, and manufacturing is possible. Cost can be reduced.

  The second feature of the present invention relates to the first feature of the present invention, and is summarized in that air having a pressure higher than atmospheric pressure is sealed in the space between the protruding portion and the substrate.

  According to this feature, air higher than atmospheric pressure is sealed in the space between the protrusion and the substrate. Thereby, since a protrusion part becomes easy to bias toward a connection part of a circuit board, the joint strength of a flexible printed circuit board and a circuit board can be improved more reliably.

  A third feature of the present invention relates to the first or second feature of the present invention, and is summarized in that the protrusion is formed in a substantially trapezoidal shape in a longitudinal section of the flexible printed board.

  According to this feature, the protrusion is formed in a substantially trapezoidal shape in the longitudinal section of the flexible printed circuit board. This makes it easier for the protruding portion to be biased toward the connection portion of the circuit board, and it is easy to secure a contact area between the protruding surface (protruding surface) and the connection portion of the circuit board. The bonding strength with the substrate can be improved more reliably.

  A fourth feature of the present invention relates to the first to third features of the present invention, wherein the connection portion includes a terminal (terminal 111) electrically connected to the conductor pattern, and a housing (housing) that covers the terminal. 112), and the protruding portion biases the terminal toward the inner surface of the housing in a state where the flexible printed circuit board is connected to the circuit board. To do.

  According to such a feature, the protruding portion urges the terminal toward the inner surface of the housing opposite to the urging force of the terminal provided in the connector, so that the bonding strength between the flexible printed circuit board and the circuit board is reliably improved. be able to.

  A fifth feature of the present invention relates to the first to third features of the present invention, wherein the connection portion is constituted by a copper foil body (copper foil body 120) electrically connected to the conductor pattern, The projecting portion is characterized in that the copper foil body is biased toward the circuit board in a state where the flexible printed circuit board is connected to the circuit board.

  According to this feature, the protruding portion urges the copper foil body toward the circuit board in a state where the flexible printed board and the circuit board are fixed with screws or the like. For this reason, the bonding strength between the flexible printed circuit board and the circuit board can be improved without performing soldering or the like.

  A sixth feature of the present invention is a flexible printed circuit board mounting structure having a mounting section that is mounted to a connection section of a mating circuit board, wherein the flexible printed circuit board is laminated on the board, and the connection is made. And a base film on which a conductive pattern connected to the portion is formed, and at a position corresponding to the mounting portion of the base film, it projects toward the opposite side of the substrate to form a space with the substrate. In addition, the gist is that a projecting portion that is displaceable in the projecting direction is provided.

  According to the features of the present invention, it is possible to reduce the manufacturing cost and reliably improve the bonding strength with the circuit board on the other side, and the flexible printed circuit board used in the board connection structure. An attachment structure can be provided.

FIG. 1 is a perspective view for explaining a substrate connection structure 1 according to the first embodiment. FIG. 2 is a cross-sectional view (before fitting) for explaining the board connecting structure 1 according to the first embodiment. FIG. 3 is a cross-sectional view (after fitting) for explaining the board connection structure 1 according to the first embodiment. FIG. 4 is a cross-sectional view showing an FPC 200A according to the first modification. FIG. 5 is a cross-sectional view illustrating an FPC 200B according to the second modification. FIG. 6 is a perspective view for explaining the substrate connection structure 1 according to the second embodiment. FIG. 7 is a cross-sectional view (after fitting) for explaining the board connecting structure 1 according to the second embodiment.

  Next, an embodiment of a substrate connection structure according to the present invention will be described with reference to the drawings. Specifically, (1) the first embodiment, (2) the second embodiment, and (3) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) First Embodiment In the following, (1-1) Description of the substrate connection structure 1, (1-2) Description of a method for manufacturing an FPC, (1-3) Actions and effects, (1-4) Modification examples Will be described in the order.

(1-1) Description of Board Connection Structure 1 First, the board connection structure 1 according to the first embodiment will be described with reference to FIGS. FIG. 1 is a perspective view for explaining a substrate connection structure 1 according to the first embodiment. FIG. 2 is a cross-sectional view (before fitting) for explaining the board connecting structure 1 according to the first embodiment. FIG. 3 is a cross-sectional view (after fitting) for explaining the board connection structure 1 according to the first embodiment.

  As shown in FIG. 1, the board connection structure 1 includes a circuit board 100 having a conductive connection part 101 and a flexible printed board (hereinafter referred to as an FPC 200) having an attachment part 201 attached to the connection part 101. In this structure, the FPC 200 is connected to the circuit board 100.

  The circuit board 100 has a plate shape. In the first embodiment, the connection portion 101 of the circuit board 100 is assumed to be a connector 110 as shown in FIGS. The connector 110 includes a terminal 111 having a spring structure that is electrically connected to a mounting portion 201 (a conductor pattern 221 to be described later) of the FPC 200, and a housing 112 that is attached to the circuit board 100 and covers the terminal 111. . The FPC 200 is attached to the circuit board 100 by inserting the attachment portion 201 of the FPC 200 into the opening 112 </ b> A of the housing 112.

  The FPC 200 includes a substrate 210 and a base film 220 laminated on the substrate 210. The substrate 210 has a plate shape and has an insulating property. The substrate 210 is formed of a member harder than the base film 220 and reinforces the base film 220. On the other hand, the base film 220 has a plate shape and is formed of a resin such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate). A conductive pattern 221 made of a conductive foil connected to the connection portion 101 of the circuit board 100 is formed on the base film 220. That is, the part corresponding to the attachment part 201 of the conductor pattern 221 is connected to the terminal 111 in the connection part 101.

  A protrusion 222 that protrudes toward the opposite side of the substrate 210 and forms a space S with the substrate 210 is provided at a position corresponding to the attachment portion 201 of the base film 220. The protrusion 222 can be displaced with respect to the protrusion direction (that is, the vertical direction). In the first embodiment, the protrusion 222 urges the terminal 111 toward the inner surface of the housing 112 in a state where the FPC 200 is connected to the circuit board 100. Air higher than atmospheric pressure is sealed in the space S between the protrusion 222 and the substrate 210.

  As shown in FIGS. 2 and 3, such a protrusion 222 is formed in a substantially trapezoidal shape in a cross section in the longitudinal direction of the FPC 200 (that is, the insertion direction of the FPC 200). Specifically, the protruding portion 222 includes a protruding surface 223 and a pair of inclined surfaces 224 that are inclined from the protruding surface 223 toward the substrate 210.

(1-2) Description of FPC Manufacturing Method Next, an FPC manufacturing method used for the above-described substrate connection structure 1 will be described with reference to FIG. This FPC manufacturing method includes a cover film forming step, a protrusion forming step, and a film laminating step.

  First, as shown in FIG. 2, in the cover film forming step, a conductor pattern 221 is formed on the base film 220.

  Next, in the protruding portion forming step, a protruding portion 222 protruding toward the opposite side of the substrate 210 is formed at a position corresponding to the mounting portion 201 of the base film 220. At this time, the conductor pattern 221 located on the protrusion 222 (protrusion surface 223) also protrudes along the shape of the protrusion 222.

  Next, in the film laminating step, the base film 220 is laminated on the substrate 210 in a state where the space S between the protrusion 222 and the substrate 210 is formed. At this time, the space S is sealed with a gas higher than the atmospheric pressure.

  The FPC 200 is attached to the circuit board 100 by inserting the mounting part 201 of the FPC 200 formed in this way into the circuit board 100 (the opening 112A of the housing 112).

(1-3) Actions / Effects In the first embodiment described above, the projecting portion 222 projects toward the opposite side of the substrate 210 to form a space S between the substrate 210 and the projecting direction. Displaceable. As a result, when the attachment portion 201 of the FPC 200 is attached to the connection portion 101 of the circuit board 100, the protrusion 222 is biased toward the connection portion 101 of the circuit board 100, so that the FPC 200 and the circuit board 100 are joined. Strength can be improved reliably.

  When the board connection structure 1 according to the present invention is used in the connector-type mounting method as in the first embodiment, the protruding portion 222 has a housing facing the urging force of the terminal 111 having a spring structure provided in the connector 110. Since the terminal 111 is urged toward the inner surface of 112, the bonding strength between the FPC 200 and the circuit board 100 can be reliably improved.

  As described above, since the bonding strength between the FPC 200 and the circuit board 100 can be improved only by providing the protruding portion 222 at a position corresponding to the mounting portion 201 of the base film 220, a step of performing soldering or the like is not necessary. The manufacturing cost can be reduced.

  In the first embodiment, air higher than atmospheric pressure is sealed in the space S between the protrusion 222 and the substrate 210. Accordingly, the protruding portion 222 is easily urged toward the connecting portion 101 of the circuit board 100 (that is, the terminal 111 in the housing 112 of the connector 110) (the urging force is improved). The bonding strength can be improved more reliably.

  In the first embodiment, the protrusion 222 is formed in a substantially trapezoidal shape in the longitudinal section of the FPC 200. Accordingly, the protruding portion 222 is easily biased toward the connecting portion 101 of the circuit board 100 (that is, the terminal 111 in the housing 112 of the connector 110), and the protruding portion 223 and the connecting portion 101 of the circuit board 100 are protruded. Therefore, the bonding strength between the FPC 200 and the circuit board 100 can be more reliably improved.

(1-4) Modification Example Next, a modification example of the FPC 200 used in the board connection structure 1 according to the first embodiment described above will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part as FPC200 which concerns on 1st Embodiment mentioned above, and a different part is mainly demonstrated.

(1-4-1) Modification 1
First, the configuration of the FPC 200A according to the first modification will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing an FPC 200A according to the first modification.

  In the first embodiment described above, the protrusion 222 is formed in a substantially trapezoidal shape in the longitudinal section of the FPC 200. On the other hand, in the first modification, as shown in FIG. 4, the protrusion 222 </ b> A is formed in a substantially semicircular shape in the longitudinal section of the FPC 200.

  In the first modification described above, the protrusion 222A is formed in a substantially semicircular shape, so that the protrusion 222 faces the inner surface of the housing 112 regardless of the shape of the terminal 111 on the circuit board 100 on the other side. Since the terminal 111 is energized, the bonding strength between the FPC 200 and the circuit board 100 can be reliably improved.

(1-4-2) Modification 2
Next, the configuration of the FPC 200B according to Modification 2 will be described with reference to the drawings. FIG. 5 is a cross-sectional view illustrating an FPC 200B according to the second modification.

  In the first embodiment described above, the protrusion 222 is formed in a substantially trapezoidal shape in the longitudinal section of the FPC 200. On the other hand, in the modified example 2, as shown in FIG. 5, the protrusion 222 </ b> B is formed in a substantially triangular shape in the longitudinal section of the FPC 200.

  Specifically, the protrusion 222B includes a front inclined surface 225 located on the insertion tip side and a rear inclined surface 226 located on the rear side. The inclination angle (θ225) of the front inclined surface 225 with respect to the substrate 210 is preferably smaller than the inclination angle (θ226) of the rear inclined surface 226 with respect to the substrate 210.

  In the modified example 2 described above, since the protruding portion 222B is formed in a substantially triangular shape, the protruding portion 222 is directed toward the inner surface of the housing 112 regardless of the shape of the terminal 111 in the counterpart circuit board 100. Since 111 is energized, the bonding strength between the FPC 200 and the circuit board 100 can be reliably improved.

  Further, since the inclination angle (θ225) is smaller than the inclination angle (θ226), the FPC 200 can be easily inserted into the connector 110 in the circuit board 100 on the mating side, and the FPC 200 can be prevented from being pulled out from the connector 110.

(2) Second Embodiment Hereinafter, (2-1) the configuration of the circuit board 100A, and (2-2) actions and effects will be described in this order. In addition, the same code | symbol is attached | subjected to the same part as the circuit board 100 which concerns on 1st Embodiment mentioned above, and a different part is mainly demonstrated.

(2-1) Configuration of Circuit Board 100A First, the configuration of the circuit board 100A used in the board connection structure 1 according to the second embodiment will be described with reference to FIG. FIG. 6 is a perspective view for explaining the substrate connection structure 1 according to the second embodiment. FIG. 7 is a cross-sectional view (after fitting) for explaining the board connecting structure 1 according to the second embodiment.

  In the first embodiment described above, the connection portion 101 of the circuit board 100 is constituted by the connector 110. On the other hand, in 2nd Embodiment, as shown in FIG. 6, 101 A of connection parts of the circuit board 100A are the copper foil bodies 120 formed with the material similar to the conductor pattern 221. As shown in FIG. The copper foil body 120 is electrically connected to the conductor pattern 221 located on the protrusion 222A formed on the base film 220, and is printed on the circuit board 100A.

  The circuit board 100A and the FPC 200A are fixed by fixing means (in the drawing, a screw 310 and a nut 320) through a hole 102 formed in the circuit board 100A and a hole 202 formed in the FPC 200A. At this time, a spacer 330 is preferably provided between the circuit board 100A and the FPC 200A.

  Here, the protrusion 222A urges the copper foil body 120 toward the circuit board 100A in a state where the FPC 200A is connected to the circuit board 100A (that is, a state where the FPC 200A is fixed by the fixing means described above).

  In addition, in 2nd Embodiment, although it is the substantially semicircle shape demonstrated in the modification 1 as protrusion part 222A formed in the base film 220 in FIG.6 and FIG.7, it is not necessarily required to be a substantially semicircle shape. Instead, it may be the substantially trapezoidal shape described in the first embodiment, or may be the substantially triangular shape described in the second modification.

(2-2) Actions / Effects As in the second embodiment described above, when the board connection structure 1 of the present invention is used in the screw mounting method, the FPC 200A and the circuit board 100A are fixed with the screws 310. The protruding portion 222A biases the copper foil body 120 toward the circuit board 100A. For this reason, the bonding strength between the FPC 200A and the circuit board 100A can be improved without performing soldering or the like.

  In particular, a spacer 330 is preferably provided between the circuit board 100A and the FPC 200A. Thereby, the protrusion 222A can urge the copper foil body 120 toward the circuit board 100A while preventing the protrusion 222A from being crushed.

(3) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. Specifically, the space S between the projecting portion 222 and the substrate 210 has been described as being sealed with air that is higher than atmospheric pressure, but is not limited thereto, and is equivalent to, for example, atmospheric pressure. The air may be sealed.

  Further, although the FPC 200 has been described as including the substrate 210 and the base film 220 on which the conductor pattern 221 is formed, the FPC 200 is not limited thereto, and further includes a cover film that covers the base film 220. It may be.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Board connection structure 100,100A ... Circuit board 101, 101A ... Connection part 110 ... Connector 111 ... Terminal 112 ... Housing 120 ... Copper foil body 200, 200A, 200B ... FPC (flexible printed circuit board)
201 ... Mounting part 210 ... Substrate 220 ... Base film 221 ... Conductor pattern 222, 222A, 222B ... Protrusion

Claims (6)

A circuit board having a connection part capable of conduction, and a flexible printed board having a mounting part attached to the connection part, and a board connection structure for connecting the flexible printed board to the circuit board,
The flexible printed circuit board is
An insulating substrate;
A base film on which a conductor pattern that is laminated on the substrate and connected to the connection portion is formed;
At the position corresponding to the mounting portion of the base film, a protrusion that protrudes toward the opposite side of the substrate to form a space in which air is sealed between the substrate and the protrusion that can be displaced with respect to the protrusion direction. A board connection structure characterized in that a portion is provided. The board connection structure according to claim 1,
The board connection structure, wherein air higher than atmospheric pressure is sealed in a space between the protrusion and the board. The board connection structure according to claim 1 or 2,
The protrusion is formed in a substantially trapezoidal shape in a longitudinal section of the flexible printed circuit board. The board connection structure according to any one of claims 1 to 3,
The connection portion is constituted by a connector including a terminal that is electrically connected to the conductor pattern, and a housing that covers the terminal,
The board connecting structure according to claim 1, wherein the protrusion biases the terminal toward the inner surface of the housing in a state where the flexible printed board is connected to the circuit board. The board connection structure according to any one of claims 1 to 3,
The connection portion is constituted by a copper foil body that is electrically connected to the conductor pattern,
The board connecting structure according to claim 1, wherein the protrusion urges the copper foil body toward the circuit board in a state where the flexible printed board is connected to the circuit board. A flexible printed circuit board mounting structure having a mounting part that is attached to a connection part of a counterpart circuit board,
An insulating substrate;
A base film on which a conductor pattern that is laminated on the substrate and connected to the connection portion is formed;
At the position corresponding to the mounting portion of the base film, a protrusion that protrudes toward the opposite side of the substrate to form a space in which air is sealed between the substrate and the protrusion that can be displaced with respect to the protrusion direction. A structure for mounting a flexible printed circuit board, wherein a portion is provided.

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