JP2009246081A - Terminal structure using flexible circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal structure using a flexible circuit board which enables the electrical connections of circuit wirings and an external circuit or the like, without using any connector, and can effectively inhibit poor contact due to the distortion of a contact terminal part caused by the flexibility of the flexible circuit board. <P>SOLUTION: The terminal structure is provide with: a base material 1 which is made of an insulating material; a conductor circuit 2 which is formed in one surface of the base material; and a covering layer 3 which covers the conductor circuit. In the covering layer, the flexible circuit board is used, wherein an opening 3a, in which a part 2b of the conductor circuit is exposed, is formed. A curvature A is formed so that the opening 3a formed in the covering layer 3 may face outward. Reinforcement members 4a and 4b, which keep the shape of the curvature, are inserted into the flexible circuit board whose surfaces are opposed to each other by the formation of the curvature. The conductor circuit 2b, which is exposed from the opening of the covering layer in the curvature A, constitutes an electrical contact terminal with the external circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a terminal structure in which a flexible circuit board is used and a contact terminal that can be electrically connected to an external circuit or the like is formed on a part of the flexible circuit board.

  With recent demands for thinner and lighter electronic devices, not only high density integration of electronic circuit components but also flexible circuit boards that are easy to bend from the viewpoint of mounting space. Hereinafter, this is also referred to as FPC).

  According to the FPC described above, the device can be mounted while being folded in a narrow space in the device, and a part of the FPC can be fixed to the case inner wall of the device by using, for example, an adhesive. It has characteristics such as excellent workability.

In the case of using the above-described FPC and connecting it to an external circuit or the like, a connector for external connection has been conventionally used. Examples thereof have been proposed in Patent Documents 1 and 2.
JP 2000-82541 A JP 2002-324610 A

  According to the disclosure of Patent Document 1, a flat connector is attached to an end portion of the FPC, and the connector is detachably connected to a contact terminal formed on, for example, a rigid circuit board via the connector. It is configured.

  Also, according to the disclosure of Patent Document 2, a flat connector is similarly attached to the end of the FPC, and the connector is configured to be connected to an external circuit or the like using the lead terminals arranged in a horizontal line on the connector. Has been. That is, in any of the above-described configurations, when each wiring arranged in the FPC is detachably connected to an external circuit or the like, a flat connector is attached to the end of the FPC.

  By the way, the flat connector described above is much thicker than the thickness of the FPC, and the connector occupies a large volume. Therefore, in a device that is intended to be thinned or miniaturized, the mounting space is particularly small. Improvement is required from the viewpoint. In addition, an increase in product cost due to the use of the connector is inevitable.

  The present invention has been made paying attention to the technical problems described above, and electrically connects the circuit wiring of the FPC and the external circuit etc. without adopting the above-described connector which takes up a large occupied volume. In this case, it is an object to provide a terminal structure using a flexible circuit board capable of effectively suppressing contact failure due to deformation of the contact terminal portion caused by the flexibility of the FPC. It is what.

  A terminal structure using a flexible circuit board according to the present invention made to solve the above-described problems includes a base substrate made of an insulating material, a conductor circuit formed on one surface of the base substrate, and the conductor circuit. And a flexible circuit board having an opening in which a part of the conductor circuit is exposed is used for the covering layer, and the opening formed in the covering layer is on the outside. Bending portions are formed so as to face each other, and inside the flexible circuit boards facing each other by the formation of the bending portions, a reinforcing member that holds the shape of the bending portions is interposed, and the coating layer in the bending portions is formed. The conductor circuit exposed from the opening is characterized in that it constitutes an electrical contact terminal with an external circuit.

  In this case, in one preferred embodiment, an exposed portion of a plurality of conductor circuits is formed along the longitudinal direction of the bent portion. And it is desirable that the reinforcing member that retains the shape of the bent portion described above is provided on one or both surfaces of the flexible circuit board facing each other by bending.

  According to the terminal structure using the flexible circuit board having the above-described configuration, the bent portion is formed so that the opening formed in the covering layer and exposing a part of the conductor circuit faces outward. It is possible to constitute an electrical contact terminal with an external circuit in the flexible circuit board.

  In addition, since a reinforcing member for holding the shape of the bent portion is interposed inside the flexible circuit board facing each other due to the formation of the bent portion, the contact terminal portion due to the flexibility of the flexible circuit board is interposed. Deformation can be prevented and contact failure can be effectively suppressed.

  And since the connector mentioned above becomes unnecessary, the problem of the occupied volume by utilizing a connector can also be eliminated, and it can also contribute to reducing product cost.

  Hereinafter, a terminal structure using a flexible circuit board according to the present invention will be described based on embodiments shown in the drawings. 1 to 3 show the first embodiment, FIG. 1 shows a cross-sectional view of a bent portion of an FPC, and FIG. 2 shows the FPC in FIG. 1 viewed from the coating layer side. FIG. 3 is a plan view of a state where a conductor circuit is seen through, and FIG. 3 is a cross-sectional view showing a state in which a terminal structure is formed at a bent portion by bending an FPC.

  The FCP in this embodiment forms a single-sided flexible circuit board by a base substrate 1 made of an insulating material, a conductor circuit 2 formed on one surface of the base substrate, and a covering layer 3 covering the conductor circuit. ing. The base substrate 1 uses a laminated plate in which copper foil is laminated on one side, and a conductive circuit 2 composed of a wiring portion 2a and a pad portion 2b is formed by, for example, an etching process.

  Then, on the surface on which the conductor circuit 2 is formed, a covering layer 3 having an opening 3a where the pad portion 2b is exposed corresponding to the position where the pad portion 2b is formed is laminated. It is composed.

  For example, a polyester film or a polyimide film can be used for the base substrate 1 described above. Among these, the polyimide film is preferable in that it has heat resistance, can sufficiently withstand the soldering temperature at the time of component mounting, and can exhibit stable performance against environmental changes after being actually incorporated into equipment. . In addition, the thickness of the base substrate 1 is usually 12.5 to 50 μm.

  Further, the copper foil forming the conductor circuit 2 may be either an electrolytic copper foil or a rolled copper foil. The thickness of the copper foil is not particularly limited, but is appropriately determined in the range of 10 to 35 μm. Further, in the flexible printed circuit board, the adhesion between the base substrate 1 and the conductor circuit 2 is not particularly limited, and either adhesion using an adhesive or adhesion without using an adhesive can be employed.

  Further, the covering layer 3 is not particularly limited, and for example, a coverlay film composed of a film and an adhesive can be suitably used. Although it does not restrict | limit especially as a raw material of the said coverlay film, For example, a polyester film and a polyimide film can be used. Among these, it is preferable to use the same material as the base substrate 1 in terms of preventing curling and warping of the product in the heating process during manufacturing. Moreover, as the adhesive, a thermosetting resin such as an epoxy resin or an acrylic resin can be suitably used.

  As shown in FIG. 3, the FPC having the above-described configuration is bent by approximately 180 degrees so that the opening 3a formed in the coating layer 3 faces outward, and a bent portion A is formed at the end. That is, in this embodiment, the bent portion A is formed at a position where the four pad portions 2b are arranged on a line orthogonal to the longitudinal direction of the FPC. Reinforcing members 4a and 4b that hold the form of the bent portion A are interposed on the opposing surfaces of the base substrate 1 that constitute the FPCs that face each other by forming the bent portion A, and these are mutually connected. The form of the bent portion A is maintained by being bonded with an adhesive.

  That is, the reinforcing members 4a and 4b are respectively attached to predetermined positions on the base substrate 1 constituting the FPC as shown in FIG. 1 by, for example, an adhesive, and are indicated by arrows in FIG. Thus, by overlapping and adhering the reinforcing member 4a to the reinforcing member 4b, the bent portion A is formed as shown in FIG.

  The reinforcing members 4a and 4b described above can use, for example, a glass fiber substrate such as a glass woven fabric or a glass nonwoven fabric in terms of strength in addition to a resin film. In addition, when using a resin film as reinforcement member 4a, 4b, the polyester film similar to the above-mentioned base substrate 1, a polyimide film, etc. can be used. The adhesion of the reinforcing members 4a and 4b to the base substrate 1 and the adhesion between the reinforcing members 4a and 4b are not particularly limited. For example, a thermosetting resin such as an epoxy resin or an acrylic resin is used. It can be preferably used.

  According to the embodiment shown in FIGS. 1 to 3, the bent portion A is in a state where the four pad portions 2 b are exposed from the opening portion 3 a of the covering layer 3 along the longitudinal direction of the bent end portion. Configured. These pad portions 2b can constitute electrical contact terminals with an external circuit or the like indicated by white arrows in FIG.

  In this embodiment, since the reinforcing members 4a and 4b for holding the bent portion are used on the back side of the bent portion A, the reinforcing members 4a and 4b make the flexible circuit board flexible. It is possible to obtain the operational effects described in the above-mentioned column of the effect of the invention, such as preventing the deformation of the contact terminal portion caused and effectively suppressing the contact failure.

  In addition, according to the above-described embodiment, the circuit board portion other than the bent portion A can be mounted while being bent in a narrow space of the device in a complicated manner by taking advantage of its flexible characteristics, and a part of the FPC can be mounted. It is also possible to expect an operational effect such as improving the workability of mounting by fixing, for example, by using an adhesive material on the case inner wall of the device.

  In the above-described embodiment, the reinforcing members 4a and 4b are each formed in a rectangular parallelepiped shape having substantially the same dimensions, and are formed with a width substantially the same as the width of the FPC as shown in FIG. Depending on the arrangement state of the pad portion 2b in the bent portion A, it may be formed in a state narrower than the width of the FPC. Further, by forming the reinforcing members 4a and 4b wider than the width of the FPC, the reinforcing member protruding in the width direction of the FPC can be used as a contact terminal positioning means.

  Next, FIG. 4 and FIG. 5 show a second embodiment of the present invention. FIG. 4 shows a cross-sectional view of the bent portion of the FPC, and FIG. 5 shows the bent by bending the FPC. The state which formed the terminal structure in the part is shown with sectional drawing. That is, FIGS. 4 and 5 correspond to sectional views in the same state as FIGS. 1 and 3 already described. 4 and 5, parts corresponding to those in FIGS. 1 to 3 already described are denoted by the same reference numerals, and therefore detailed description thereof is omitted.

  The second embodiment is different from the first embodiment in that a reinforcing member for forming the bent portion A is a single rectangular parallelepiped shape as indicated by reference numeral 4. . That is, in the second embodiment, the reinforcing member 4 is attached to a predetermined position of the base substrate 1 constituting the FPC with an adhesive, for example, as shown in FIG.

  In this state, the FPC is bent along the end surface and the opposing surface of the reinforcing member 4, and an appropriate adhesive is used to form a bent portion A as shown in FIG. Can be formed. Therefore, also in the second embodiment shown in FIGS. 4 and 5, the same operational effects as those in the first embodiment shown in FIGS. 1 to 3 can be obtained.

  In the embodiment described above, the terminal structure is formed at the bent portion using the single-sided flexible circuit board, but this forms a similar terminal structure by using the flexible circuit board having a multilayer structure. You can also

  In the first and second embodiments described above, the contact terminal formed by the pad portion 2b formed in the bent portion A can achieve electrical connection with an external circuit. It can also be used as a terminal for receiving an electrical connection with a rigid board on which an electronic circuit component is mounted, for example, a power source from a battery pack or the like.

  The terminal structure using the flexible circuit board according to the present invention can be suitably used particularly in electronic devices that are difficult to secure a mounting space and are intended to be thinned and miniaturized.

It is sectional drawing of the part by which the flexible circuit board in the 1st Embodiment of this invention is bent. FIG. 2 is a plan view of a state in which the flexible circuit board in FIG. 1 is seen through a conductor circuit viewed from a coating layer side. It is sectional drawing which shows the state which formed the terminal structure by bending the flexible circuit board in 1st Embodiment. It is sectional drawing of the bent part of the flexible circuit board in 2nd Embodiment of this invention. It is sectional drawing which shows the state which formed the terminal structure by bending the flexible circuit board in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base base material 2 Conductor circuit 2a Wiring part 2b Pad part 3 Covering layer 3a Opening part 4, 4a, 4b Reinforcement member A Bending part

Claims (3)

A base substrate made of an insulating material, a conductor circuit formed on one surface of the base substrate, and a coating layer covering the conductor circuit are provided, and a part of the conductor circuit is exposed in the coating layer. A flexible circuit board having an opening to be used is used,
A bent portion is formed such that the opening formed in the coating layer faces outward, and the inside of the flexible circuit board opposed to each other by the formation of the bent portion is reinforced to maintain the shape of the bent portion. Members are intervened,
A terminal structure using a flexible circuit board, wherein the conductor circuit exposed from the opening of the coating layer in the bent portion constitutes an electrical contact terminal with an external circuit.   The terminal structure using a flexible circuit board according to claim 1, wherein exposed portions of a plurality of conductor circuits are formed along a longitudinal direction of the bent portion.   3. The flexible circuit board according to claim 1, wherein the reinforcing member that holds the shape of the bent portion is provided on one or both surfaces of the flexible circuit board facing each other by bending. Terminal structure using

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