JP2005191162A - Rigid-flexible wiring board and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rigid-flexible wiring board which prevents stress from being concentrated on metal wiring at the boundary between a rigid part and a flexible part of the rigid-flexible board to avoid damage to the metal wiring or the breakage of wires at bending the flexible part. <P>SOLUTION: At the boundary between a rigid part and a flexible part, a part of the rigid part is projected to a portion having no metal wiring and the projected part is bent to concentrate stresses for bending the flexible part on the projected part, resulting in that the stresses are hardly exerted on the metal wiring to avoid the breakage of wires. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a rigid flexible wiring board, and more particularly to a technique for preventing disconnection of metal wiring caused by bending at a boundary portion between a flexible wiring board and a rigid printed wiring board.

  The rigid flexible wiring board is a wiring board that has both the hardness to secure the electronic component mounting characteristic of the rigid printed wiring board and the softness to ensure the flexibility characteristic of the flexible printed wiring board. And has been used in many small devices.

  FIG. 9 is a plan view of a conventional rigid flexible wiring board used for the above purpose. In FIG. 9, reference numeral 1 denotes a rigid portion, and 2 denotes an exposed flexible portion that is a portion exposed from the rigid portion 1. Electrical connection is made by 7 electronic parts mounted on the rigid part 1, 11 rigid metal wiring on the rigid printed wiring board, and 12 flexible metal wiring on the flexible printed wiring board through 12 through holes. Consists of connecting. When actually used in a product, the electrical connection is configured, and the exposed flexible portion 2 is bent and used. At this time, it bends at the boundary portion 9c between the rigid portion 1 and the exposed flexible portion 2.

  The state bent at the boundary portion 9c will be described with reference to FIG. FIG. 10 is a cross-sectional view taken along the line C-C ′ of FIG. 9 in a state where a rigid flexible wiring board according to an embodiment of the prior art is bent. As shown in FIG. 10, the rigid flexible wiring board is configured such that a flexible printed wiring board composed of a flexible metal wiring 4 and a cover film 5 is sandwiched from both sides by a rigid material 10 of the rigid printed wiring board. Has been.

  When the electronic component 7 or the like is mounted, it is mounted on the rigid material 10. Further, the electronic component 7 and the flexible metal wiring are connected via the rigid metal wiring 11 and the through hole 12.

  In actual use, the exposed flexible portion 2 is bent so that the exposed flexible portion 2 extending from the boundary portion 9c between the rigid portion 1 and the exposed flexible portion 2 is pulled in the N direction due to tension. For this reason, the bending of the exposed flexible portion 2 becomes a portion where the boundary portion 9c between the rigid portion 1 and the exposed flexible portion 2 that is the bending start point becomes an acute angle due to the bending, and stress is concentrated. In particular, the flexible metal wiring 4 at the boundary portion 9c is harder and thinner than the base film 6 and the cover film 5, so that there is a problem that it is easily disconnected.

In the prior art as a method of preventing the disconnection of the metal wiring due to the bending as described above, the cover film at both ends without the metal wiring is projected at the opening of the cover film of the flexible portion, and is bent at this protruding portion, There is a method for preventing stress from concentrating on metal wiring. This method is a method of opening the cover film, exposing the metal wiring of the flexible portion, and preventing disconnection due to bending at a portion used as a connection terminal for connecting to a connector or the like, and the cover film is open This is effective for preventing disconnection at the time of bending in the portion. (For example, see Patent Document 1)
In Patent Document 1, since the convex portion is composed of a cover lay which is a material of the flexible portion, when the flexible portion is bent, the convex portion is bent to the convex portion and is effective in the sense of concentrating stress on the convex portion. There are few problems.

  Moreover, in the rigid flexible wiring board, in the conventional technique as a method for preventing the breakage of the flexible portion at the boundary portion between the rigid portion and the flexible portion and the damage of the metal wiring, an organic resin composition is applied to the boundary portion between the rigid portion and the flexible portion. Sealing with a dispenser or the like is effective in preventing disconnection at the time of bending since it can be indicated with elasticity by the organic resin composition when bent at the boundary between the rigid portion and the flexible portion. (For example, see Patent Document 2)

JP 2001-318618 A JP-A-7-106728

  The prior art described in Patent Document 1 is effective in preventing disconnection at the time of bending in the portion where the cover film is open. However, unlike bending at the boundary between the flexible part and the rigid part on the rigid flexible wiring board, it is not considered to prevent disconnection at the part that is not the opening of the cover film, and bending at the boundary part of the rigid part is not considered. There is a problem that the metal wiring sometimes breaks easily.

  Moreover, in the prior art described in the above-mentioned Patent Document 2, when it is bent at the boundary between the rigid part and the flexible part, the organic resin composition can give instructions with elasticity, which is effective in preventing disconnection during bending. It is. However, in addition to the manufacturing process of the rigid flexible wiring board, there is a problem that the number of processes for sealing with a dispenser or the like increases and the manufacturing cost increases.

  The object of the present invention is to prevent damage and disconnection of the metal wiring in the flexible portion by preventing stress from concentrating on the metal wiring at the boundary between the rigid portion and the flexible portion of the rigid flexible wiring board. At the same time, it is to provide a rigid flexible wiring board which does not increase the number of manufacturing steps.

  In order to solve the above problems, the present invention provides a rigid flexible wiring board in which a metal wiring is formed on a base film and the surface is protected with a cover film, and the rigid printed wiring board is integrated. One or more protruding protrusions are formed on the rigid portion at the boundary with the flexible portion. By projecting a part of such a rigid part and bending it at this protruding part, it is bent at this protruding part and stress is not concentrated on the metal wiring. Damage and disconnection of metal wiring can be avoided. Furthermore, since the number of manufacturing steps is not increased, an increase in cost can be avoided.

  Furthermore, the protruding portion having the convex shape is formed in a portion of the flexible portion having no metal wiring. With such a configuration, the metal wire can be bent at a portion where there is no metal wiring, so that stress can be prevented from being concentrated on the metal wiring.

  Furthermore, the convex protrusions are formed on both ends of the flexible part. Since both ends of the flexible part originally have a portion without metal wiring, it is possible to prevent the flexible part from becoming large by arranging the projecting protrusions on both ends of the flexible part.

  According to the present invention, at the boundary portion between the rigid portion and the flexible portion of the rigid flexible wiring board, a part of the rigid portion is projected and bent at the protruding portion so that stress is not concentrated on the metal wiring. The damage and disconnection of the metal wiring in the flexible part can be avoided. Furthermore, since the number of manufacturing steps is not increased, an increase in cost can be avoided.

  The rigid flexible wiring board of the present invention achieves the purpose of improving the bending characteristics of the rigid part and the flexible part without increasing the number of steps in the manufacturing process of the rigid flexible wiring board.

  Embodiments of the present invention will be described below with reference to FIGS. In addition, the same number is used about the same part, and description of the same number is abbreviate | omitted.

  First, the configuration of a rigid flexible wiring board according to the present invention will be described with reference to FIG. FIG. 1 shows an embodiment of a plan view of a rigid flexible wiring board according to the present invention. 3 is a convex protrusion formed on both side ends of the rigid part 1 at the boundary between the rigid part 1 and the flexible part 2 according to the present invention, 8 is a protrusion distance of the convex protrusion 3, and 4 is a flexible part. 9a is a boundary portion between the protruding portion 3 and the flexible portion 2, and 9b is a boundary between the flexible portion 2 where the flexible metal wiring 4 is located and the rigid portion 1 other than the protruding portion 3. Indicates the part. In addition, the convex protrusion part 3 by a present Example is provided in the both ends which the flexible metal wiring 4 is not arrange | positioned.

  A state where the flexible portion 2 is bent will be described with reference to FIGS. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1 in a state where the rigid flexible wiring board according to the present embodiment is bent, and FIG. 3 is a view of FIG. 1 in a state where the rigid flexible wiring board according to the present invention is bent. Sectional drawing in the line of BB 'is shown.

  First, how to apply stress to the boundary portion 9a during bending will be described. As shown in FIG. 3, when the flexible portion 2 is pulled in the N direction, the boundary portion 9a between the protruding protrusion 3 and the flexible portion 2 is bent at a bending position, and the stress concentrates on the boundary portion 9a. That is, this part is bent at the most acute angle. Here, since the flexible part 2 of the boundary part 9a is composed of the elastic base film 5 and the cover film 6, it is difficult to damage or cut even if stress is concentrated. Moreover, since there is no flexible wiring metal 4 here, disconnection can also be prevented.

  Next, how stress is applied to the boundary portion 9b and the flexible metal wiring 4 during bending will be described. As shown in FIG. 2, when the flexible portion 2 is pulled in the N direction, the boundary portion 9a is bent at the bending position as described above. However, the protrusion 3 having a convex shape is formed between the boundary portion 9a and the boundary portion 9b. Since there is the protrusion distance 8, the bending angle can be increased at the boundary portion 9b. Therefore, since the stress at the boundary portion 9b can be reduced, disconnection of the flexible metal wiring 4 can be prevented. Moreover, although it bends along the line which connects the boundary part 9a provided in both ends, since there is no rigid material 10 in this part, it is not bent at an acute angle by the elasticity of the base film 6 and the cover film 5. For this reason, the stress concerning the part along the line which connects the boundary part 9a provided in both ends can also be made small, and the disconnection of the flexible metal wiring 4 can be prevented.

  The protrusion distance 8 in the embodiment according to the present invention was set to 0.3 mm, which is the minimum protrusion distance that can stably process the convex shape of the rigid portion into a convex shape in the manufacturing process of the rigid flexible wiring board.

  Further, in this embodiment, the protruding portions 3 are provided on the rigid members 10 that sandwich the flexible portion 2 from both sides, but the protruding portions 3 of the rigid material protrude from the rigid portions where the flexible portion is pulled and stress is applied. Therefore, the rigid material portion on the side where the flexible portion is pulled may be convex, and the rigid portion on the side where the flexible portion is not pulled may have no convexity.

  Furthermore, the present invention is not limited to the rigid flexible wiring board, but is effective for the boundary portion of the hard board when the hard board is bonded to the flexible board.

  Here, the manufacturing method of the rigid flexible wiring board by this invention is demonstrated. For the purpose of electrically and mechanically protecting the flexible metal wiring 4 after forming the pattern by forming the flexible metal wiring 4 on the base film 6 by a method such as rolling or electrolysis, a method of casting the cover film 5 The process of the flexible printed circuit board is completed by pasting by, for example.

  Next, an adhesive is applied between the flexible printed wiring board and the rigid material 10 at a location where the rigid portion 1 is formed, and is adhered and adhered by pressure by a press or the like, whereby the flexible portion 2 and the rigid are bonded. Part 1 is configured. Thereafter, the through hole 12 is created to connect the rigid metal wiring 11 and the flexible metal wiring 4 to complete the rigid flexible wiring board.

  On the other hand, the part to be used as the flexible part 2 is not attached without the rigid member 10 being prepared, or is attached without applying the adhesive between the rigid member 10 and the flexible part 2, and then the adhesive is applied. It is also possible to provide the flexible part 2 by peeling off the rigid material 10 that is not.

  As described above, as described above, the manufacturing process of the rigid flexible wiring board is configured by creating a flexible printed wiring board and then bonding the rigid material. Here, since the convex protrusion 3 according to the present invention only changes the shape of the rigid member 10, there is no need to change the manufacturing method, so that the manufacturing cost does not increase.

FIG. 4 and FIG. 5 show the product incorporation state of this embodiment.
FIG. 5 shows a state in which the case is removed from only one side of the entire video camera product, which is an electronic device product, so that the rigid flexible wiring board can be seen. FIG. 4 is an enlarged view of the rigid flexible wiring board according to the present invention of FIG. is there.

  Reference numeral 16 denotes a circuit board A having the present invention, and 13 denotes a connector insertion portion of the circuit board A. Reference numeral 17 denotes a circuit board B which is a flexible connection destination of the circuit board A16, and reference numeral 14 denotes a connector mounted on the circuit board B.

The circuit board A16 and the circuit board B17 are electrically connected by the connector insertion portion 13 of the circuit board A16 and the connector 14 mounted on the circuit board B17.
A method for incorporating the circuit board A16 and the circuit board B17 into the product main body and a method for electrically connecting the circuit board A16 and the circuit board B17 will be described below.

  In FIG. 5, the circuit board A16 and the circuit board B17 are fixed to the product body with screws 15a, and the circuit board B17 is also fixed to the product body with screws 15b.

  The electrical connection method between the circuit board A16 and the circuit board B17 is that the circuit board A16 is inserted into the 14 connectors that are circuit connection destinations of the circuit board A16 that is the rigid flexible wiring board while supporting the connector insertion portion 13 of the circuit board A16. The connector insertion portion 13 needs to be inserted to some extent in order to stabilize the insertion state of the connector 14. For this reason, it is necessary to pull the flexible cable by the insertion width with respect to the connector insertion direction.

  If the flexible part of the connector insertion part is pulled, stress may be applied to the boundary part between the rigid part of the 9d and the flexible part and the metal wiring may be disconnected. However, the work at the time of inserting the connector is provided by providing the convex part of the present invention at the 9d part. Can prevent disconnection at the boundary between the rigid part and the flexible part.

An embodiment in another product built-in state will be described with reference to FIGS.
6 shows a circuit board incorporated in the product and a USB jack portion for exchanging signals with the outside, FIG. 7 is a cross-sectional view taken along the line AA in FIG. 6, and FIG. .

  Reference numeral 18 denotes a circuit board C in the product, and a connector 21 that is electrically connected to the 19 circuit boards D is mounted on the circuit board C18. The USB jack 22 is mounted on the circuit board D19 having the present invention and fixed to the folder 20.

As an assembling method, the USB jack 22 is mounted on the circuit board D19, and then inserted and fixed in the folder 20 with the USB jack 22 mounted on the previous circuit board D19.
As for the connection method with the circuit board C18, the circuit board C18 is first fixed at a desired fixing position, and then the circuit board D19, the USB jack 22 and the folder 20 are integrated together and fixed with a fixing screw 15c. Is done.

As an electrical connection method with the USB jack 22, the flexible part 2 of the circuit board D 19 is pulled to the connector 21 side, and the terminal exposed part at the tip of the flexible part 2 is inserted into the connector 21.
When pulling up the flexible part 2, there is a concern that stress is applied to the boundary part between the circuit board D19 which is a rigid board of 9e and the flexible part 2 and the metal wiring is disconnected, but the convex part of the present invention is connected to the boundary part 9e part. By providing the rigid portion, disconnection of the metal wiring of the flexible portion at the boundary between the rigid portion and the flexible portion can be prevented.

The top view of the rigid flexible wiring board by this invention Sectional drawing of the state which bent the rigid flexible wiring board by this invention Sectional drawing of the state which bent the rigid flexible wiring board by this invention Three-dimensional view of actual product according to the present invention 4 is a partially enlarged view of FIG. 4 according to the present invention. Three-dimensional view of actual product according to the present invention AA sectional view of FIG. 6 according to the present invention. FIG. 7 is a partially enlarged view of the present invention. Plan view of conventional rigid flexible wiring board Cross-sectional view of a conventional rigid flexible wiring board bent

Explanation of symbols

1 ... Rigid part,
2 ... Flexible part,
3 ... convex protrusion,
4 ... Flexible metal wiring,
5 ... Cover film,
6 ... Base film,
7 ... Electronic components,
8: Projection distance of the projecting projection 3
9a: a boundary portion between the projecting portion 3 having a convex shape and the flexible portion 2,
9b ... the boundary between the rigid part and the flexible part of the part with the metal wiring,
9c: The boundary between the rigid part and the flexible part,
9d: the boundary between the rigid part and the flexible part,
9e: the boundary between the rigid part and the flexible part,
10 ... Rigid material,
11 ... Rigid metal wiring,
12 ... Through hole,
13 ... Connector insertion part,
14 ... Connector,
15a ... Board fixing screw,
15b ... Board fixing screw,
15c ... Board fixing screw,
16 ... Circuit board A,
17 ... Circuit board B,
18 ... Circuit board C,
19 ... Circuit board D,
20 ... folder,
21 ... Connector,
22 ... USB jack,
N: Flexible pulling direction.

Claims (4)

In a rigid flexible wiring board that integrates a rigid printed wiring board and a flexible printed wiring board that forms a metal wiring on a base film and protects the surface with a cover film,
A rigid flexible wiring board, wherein one or more protruding protrusions are formed in the rigid portion at the boundary between the rigid portion and the flexible portion.   2. The rigid flexible wiring board according to claim 1, wherein the protruding portion having the convex shape is formed in a portion of the flexible portion where there is no metal wiring.   3. The rigid flexible wiring board according to claim 1, wherein the projecting protrusions are formed on both ends of the flexible part. In electronic equipment using a rigid flexible wiring board that integrates a rigid printed wiring board and a flexible printed wiring board that forms a metal wiring on a base film and protects the surface with a cover film,
An electronic apparatus, wherein one or more projecting protrusions are formed on the rigid portion at a boundary between the rigid portion and the flexible portion.

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