JP4162674B2 - Flexible wiring board and electronic device - Google Patents

Description

  The present invention relates to a flexible wiring board, and more particularly to a flexible wiring board that inserts a through hole formed in a casing of an electronic device and connects a circuit inside the casing and a circuit outside the casing.

2. Description of the Related Art In recent years, portable electronic devices such as portable telephones have been mainly provided with a first housing and a second housing that are connected to each other via a hinge. A circuit board is accommodated in the first casing and the second casing, and these circuit boards are electrically connected by a flexible wiring board, and between the circuit board of the first casing and the circuit board of the second casing. Transmission / reception of electrical signals is realized. In addition, through holes are formed in the first housing and the second housing, and the flexible wiring board is guided to the inside of the first housing and the second housing through the respective through holes. In order to waterproof the submerged water, the through hole is closed with a waterproof cap (see, for example, Patent Document 1). Specifically, as shown in FIG. 6, the flexible wiring board 102 is inserted into the waterproof cap 101, and the O-ring 103 is wound around the waterproof cap 101. When the waterproof cap 101 is fitted into the through hole of the housing, the O-ring 103 and the waterproof cap 101 are pressed against the wall surface of the through hole, and the flexible wiring substrate 102 is sandwiched by the waterproof cap 101. Although waterproofing can be achieved by this, water may be submerged from between the waterproof cap 101 and the flexible wiring board 102, so that the both ends of the waterproof cap 101 are covered with the adhesive 104 around the flexible wiring board 102.
JP 2004-214927 A

Although the waterproof property is improved by applying the adhesive 104, the adhesive 104 is required in addition to the waterproof cap 101, and the application process of the adhesive 104 is also required. If the adhesive 104 is not provided, the waterproof property is deteriorated.
SUMMARY OF THE INVENTION Accordingly, the present invention provides a waterproof wiring board-integrated flexible wiring board that includes a waterproofing member for sealing a through hole for a flexible wiring board formed in a casing of an electronic device and has a simple structure. The purpose is to do.

  The invention according to claim 1 is a flexible wiring board that inserts a through hole formed in the first housing of the electronic device and electrically connects the first housing and the second housing, A flexible wiring board is provided with a shield layer having a magnetic shielding property that shields electrical noise from the wiring of the flexible wiring board using a meltable resin as a base material on each of the front side and the back side of the flexible wiring board. Further, the flexible wiring board is formed by forming a water-resistant topcoat layer that coats each shield layer from the upper layer side on the shield layer, so that the flexible wiring board has a shield layer and a topcoat layer on the surface side, And the back coat side shield layer and the top coat layer. The top coat layer on the front and back surfaces of the flexible wiring board In the state where the flexible wiring board is inserted into the through hole, a wide cut is formed at the position corresponding to the through hole so that the lower shield layer is exposed on the wide surface, and the top coat layer on the front surface side and the back surface side. A waterproof member for sealing the through hole made of a resin similar to the resin base material of the shield layer is formed on the wide surface of the lower shield layer exposed through the cut line by insert molding. The portion corresponding to the through hole of the flexible wiring board is entirely from the periphery from the front side and the back side of the flexible wiring board so as to be in close contact with the wide surface of the lower shield layer exposed through the cut line It is integrally molded so as to wrap, and in that integral molding, it is integrated so as to wrap the top coat layer around the shield layer exposed at the cut. By shape, characterized in that said waterproof member is configured to be firmly adhered to the flexible wiring board.

  According to the first aspect of the invention, since the waterproof member is integrally formed on the flexible wiring board by insert molding, the air tightness and water tightness between the waterproof member and the flexible wiring board are improved. Further, since the waterproof member is integrally formed on the flexible wiring board, the structure is simple, and it is not necessary to cover the periphery of the flexible wiring board with an adhesive.

  According to a second aspect of the present invention, in the flexible wiring board according to the first aspect, the waterproof member integrally formed with the flexible wiring board has the passage when the flexible wiring board is passed through the through hole. A flange-like flange that is locked by a hole is formed on the outer periphery of one end of the waterproofing member in the circumferential direction.

  The invention according to claim 3 is the flexible wiring board according to claim 1 or 2, wherein the waterproof member integrally formed with the flexible wiring board has the flexible wiring board passed through the through hole. A groove portion to which an elastic ring that prevents water from entering through the through-hole is attached is formed in the outer circumference of the waterproof member in the circumferential direction.

  The invention according to claim 4 is the flexible wiring board according to claim 1 or 2, wherein the waterproof member integrally formed with the flexible wiring board has the flexible wiring board passed through the through hole. A convex portion that prevents water from entering through the through-hole is formed on the outer periphery of the waterproof member in the circumferential direction.

  The invention according to claim 5 is the flexible wiring board according to any one of claims 1 to 4, wherein the resin that is a base material of the shield layer and the waterproof member is a polyester resin. Features.

  The invention according to claim 6 is an electronic device including a first housing and a second housing, and as a flexible wiring board that electrically connects the first housing and the second housing, A flexible wiring board according to any one of claims 1 to 5 is provided.

  According to a seventh aspect of the present invention, in the electronic device according to the sixth aspect, in the first casing and the second casing, a through hole for inserting the flexible wiring board is formed, respectively, and the flexible casing The waterproof member integrally formed with the wiring board is formed at two positions on the flexible wiring board corresponding to the through hole on the first housing side and the through hole on the second housing side. And

  According to the present invention, since the waterproof member is integrally formed on the flexible wiring board by insert molding, the structure is simplified and the waterproof property is further improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a perspective view of a state in which a part of the portable telephone 1 is disassembled.

  In this mobile phone 1, the first housing 2 is connected to the second housing 3 by the hinge 4, and the first housing 2 rotates with respect to the second housing 3 about the axis of the hinge 4. It is possible. When the first housing 2 is closed with respect to the second housing 3, the front surface 24 of the first housing 2 faces the front surface 34 of the second housing 3, and the first housing 2 is in contact with the first housing 2. When the housing 2 is open, both the front surface 24 of the first housing 2 and the front surface 34 of the second housing 3 are facing the front.

  FIG. 2 is a cross-sectional view of the first housing 2 taken along the cutting line II-II in FIG. As shown in FIG. 2, the first housing 2 is a waterproof housing in which an elastomeric O-ring 20 is provided over the entire circumference at the fitting portion of two case members constituting the housing. A circuit board 21 on which a display panel or the like is mounted is accommodated in the first housing 2. Although not shown, the display panel mounted on the circuit board 21 faces the front surface 24 of the first housing 2 inside the first housing 2. FIG. 3 is a cross-sectional view of the second housing 3 taken along the section line III-III in FIG. As shown in FIG. 3, the second housing 3 is also a waterproof housing in which an elastomeric O-ring 30 is provided over the entire circumference at the fitting portion of the two case members constituting the housing. A circuit board 31 on which various electronic components are mounted is also accommodated in the second housing 3. Although not shown, the waterproof key operation unit faces the front surface 34 of the second housing 3 in a state in which the waterproof key operation part partially protrudes from the front surface 34 of the second housing 3. Is provided.

  As shown in FIGS. 1 and 2, the side wall 22 on the hinge 4 side of the first housing 2 is formed with a long through hole 23 in a direction parallel to the axis of the hinge 4. 1 It penetrates from the outside to the inside of the housing 2. A band-like flexible wiring board (FPC) 5 is guided to the inside of the first housing 2 through the through hole 23, and a connector 51 provided at an end of the flexible wiring board 5 is connected to the circuit board 21.

  As shown in FIGS. 1 and 3, the side wall 32 on the hinge 4 side of the second housing 3 is formed with a long through hole 33 in a direction parallel to the axis of the hinge 4. 2 Inserted from the outside to the inside of the housing 3. The flexible wiring board 5 is guided to the inside of the second housing 3 through the through hole 33, and the connector 52 provided at the other end of the second housing 3 is connected to the circuit board 31. The circuit board 31 and the circuit board 21 are electrically connected by the flexible wiring board 5.

  FIG. 4 is a plan view of a waterproof member-integrated flexible wiring board integrally provided with a waterproof member for sealing the through hole 23 of the first housing 2 and the through hole 33 of the second housing 3. However, as shown in FIGS. 4 and 1, the width direction of the flexible wiring board 5 is parallel to the axial direction of the hinge 4, and the flexible wiring board 5 is spirally wound around the axis of the hinge 4. Yes.

  FIG. 5 is a cross-sectional view taken along the line VV in FIG. As shown in FIG. 5, the flexible wiring board 5 includes a band-shaped base film 53, a wiring 54 patterned on one surface of the base film 53, and a base film 53 on which the wiring 54 is formed from above the wiring 54. Cover film 56 covered and bonded to base film 53 and wiring 54 by adhesive layer 55, shield layer 57 formed on cover film 56, and shield formed on the other surface of base film 53 The layer 58 includes a top coat layer 59 formed on the shield layer 57 and a top coat layer 60 formed on the shield layer 58.

  The base film 53 and the cover film 56 are made of a resin such as polyimide. The wiring 54 is made of a metal such as copper or gold or a metal compound. The shield layers 57 and 58 are made of a resin such as a polyester resin as a base material, and metal particles such as silver are dispersed in the base material. Noise is less likely to occur. For example, the shield layers 57 and 58 are solidified silver paste. The topcoat layers 59 and 60 are made of a water-resistant resin such as an alkyd resin, and are formed by a coating method such as a dip coating method. The shield layers 57 and 58 are protected by the top coat layers 59 and 60.

  As shown in FIGS. 1 and 4, waterproof caps 70 and 80 (waterproofing members) having elastomeric properties are integrated with the flexible wiring board 5 by insert molding. That is, the waterproof caps 70 and 80 are formed by wrapping a part of the flexible wiring board 5 as an insert material with a molten resin and solidifying the resin, and the solidified resin becomes the waterproof caps 70 and 80. The top coat layers 59, 60 are interrupted at the portions wrapped by the waterproof caps 70, 80, and the waterproof caps 70, 80 are in close contact with the shield layers 57, 58 at the cuts of the top coat layers 59, 60. The cuts in the topcoat layers 59, 60 may be formed by applying a mask in advance when the topcoat layers 59, 60 are formed, or the topcoat layers 59, 60 may be formed after the topcoat layers 59, 60 are formed. You may form by removing a part of 59,60.

  The waterproof caps 70 and 80 are made of the same resin (for example, polyester resin) as the base material of the shield layers 57 and 58, and the adhesion between the waterproof caps 70 and 80 and the shield layers 57 and 58 is high. The adhesion between the waterproof caps 70 and 80 and the shield layers 57 and 58 is higher than the adhesion between the waterproof caps 70 and 80 and the topcoat layers 59 and 60.

  The waterproof caps 70 and 80 will be specifically described. As shown in FIG. 5, a groove 71 is formed in the outer periphery of the waterproof cap 70 in the circumferential direction, and a flange 72 is formed in the outer periphery of one end of the waterproof cap 70 in the circumferential direction. An elastomeric O-ring 73 is fitted in the groove 71. As shown in FIG. 3, the waterproof cap 80 has a groove 81 and a flange 82 formed in the same manner as the waterproof cap 70, and an elastomeric O-ring 83 is fitted in the groove 81. When viewed from one end to the other end of the flexible printed circuit board 5, the flange 72 of the waterproof cap 70 is on the waterproof cap 80 side, the flange 82 of the waterproof cap 80 is on the waterproof cap 70 side, and the flange 72 and the flange 82 are relative to each other. is doing.

  As shown in FIG. 2, the waterproof cap 70 fitted with the O-ring 73 is fitted into the through hole 23 and is pressed against the wall surface of the through hole 23. The flange 72 of the waterproof cap 70 is engaged with the side surface 21 of the first housing 2 over the entire periphery of the through hole 23, so that the waterproof cap 70 does not enter the inside of the first housing 2. Further, the waterproof cap 80 fitted with the O-ring 83 is also fitted into the through-hole 23 in a state of being pressed against the wall surface of the through-hole 33 as shown in FIG. It has stopped.

  As shown in FIGS. 2 and 3, the flexible wiring board 5 is covered with hinge covers 91 to 92 attached to the first housing 2 and hinge covers 93 to 94 attached to the second housing 3. ing. The hinge covers 91 to 94 cover the hinge 4 in addition to the flexible wiring board 5.

Next, a method for manufacturing a waterproof member-integrated flexible wiring board will be described.
First, the wiring 54 is patterned on the base film 53, and the cover film 56 is bonded to the base film 53 with the adhesive layer 55 so as to cover the wiring 54 with the cover film 56. Next, the shield layers 57 and 58 are coated, and the mask is covered from the top of the shield layers 57 and 58 to the molding portions of the waterproof caps 70 and 80. Next, the top coat layers 59 and 60 are coated and the mask is removed to form cuts in the top coat layers 59 and 60. Next, waterproof caps 70 and 80 (waterproof members) are formed by insert molding at locations where the top coat layers 59 and 60 are cut. O-rings 73 and 83 are then fitted into the grooves 71 and 81 of the waterproof caps 70 and 80, respectively.

  As described above, the waterproof caps 70, 80 fitted with the O-rings 73, 83 are fitted into the through holes 23, 33, so that water enters the inside of the first housing 2 and the second housing 3. Disappear. Since these waterproof caps 70 and 80 are integrally formed on the flexible wiring board 5 by insert molding, the airtightness and water tightness at the interface between the waterproof caps 70 and 80 and the flexible wiring board 5 are high. In particular, since the waterproof caps 70 and 80 are made of the same resin as the base material of the shield layers 57 and 58, the adhesion between the waterproof caps 70 and 80 and the shield layers 57 and 58 is high, and the airtightness and watertightness are also high. Further, even when the adhesion of the waterproof caps 70, 80 to the top coat layers 59, 60 is low, the waterproof caps 70, 80 and the shield layers 57, 58 are waterproofed.

  Since the top coat layers 59, 60 are cut and the waterproof caps 70, 80 are formed so as to wrap the flexible wiring board 5 at the cuts, the waterproof caps 70, 80 are partially embedded in the cuts to form the waterproof cap 70. , 80 is caught in the cut. Therefore, the flexible wiring board 5 is not easily detached from the waterproof caps 70 and 80, and airtightness and watertightness between the waterproof caps 70 and 80 and the flexible wiring board 5 are improved.

  Furthermore, since the waterproof caps 70 and 80 are integrally formed on the flexible wiring board 5, the structure is simple, and it is not necessary to cover the flexible wiring board 5 with an adhesive.

The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, in the above embodiment, the waterproof member integrally formed with the flexible wiring board 5 is the waterproof caps 70 and 80 having the grooves 71 and 81 in which the O-rings 73 and 83 are mounted. After forming, the groove 71, 81 is filled with an elastic material having elasticity equivalent to that of the O-rings 73, 83 by a two-color molding method, or the waterproof caps 70, 80 are made of a softer material. Alternatively, the areas where 71 and 81 are formed may be formed in a convex shape, and the waterproof caps 70 and 80 themselves may be integrally formed with a waterproof portion instead of the O-rings 73 and 83.
In the above embodiment, the portable telephone 1 is described as an example of the portable electronic device. However, a notebook personal computer, a digital camera, a wristwatch, a PDA (Personal Digital Assistance), an electronic notebook, and a portable wireless device are described. The present invention may also be applied to a case where a flexible wiring board is provided in another folding electronic device.

1 is a perspective view of a state in which a part of a mobile phone 1 is disassembled. It is sectional drawing of the 1st housing | casing 2 of the surface along the cutting line II-II of FIG. It is sectional drawing of the 2nd housing | casing 3 of the surface along the cutting line III-III of FIG. It is a top view of a waterproof member integrated flexible wiring board. It is arrow sectional drawing of the surface along the cutting line VV of FIG. It is sectional drawing of the conventional flexible wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Portable telephone device 2 1st housing | casing 3 2nd housing | casing 4 Hinge 5 Flexible wiring board 57, 58 Shield layer 59, 60 Topcoat layer 23, 33 Through-hole 70, 80 Waterproof cap

Claims (7)

A flexible wiring board that is inserted through a through hole formed in a first housing of an electronic device and electrically connects the first housing and the second housing ,
In the flexible wiring board, a shield layer having an electromagnetic shielding property that shields electrical noise from wiring of the flexible wiring board using a meltable resin as a base material is provided on each of the front side and the back side of the flexible wiring board. In addition, the flexible wiring board has a shield layer and a top coat layer on the surface side by forming a water-resistant top coat layer for coating each shield layer from the upper layer side on the shield layer. , And configured to be sandwiched between the shield layer and the top coat layer on the back side,
The top coat layer on the front and back surfaces of the flexible wiring board has a wide width in which the lower shield layer is exposed at a wide surface at a position corresponding to the through hole with the flexible wiring board inserted into the through hole. Each cut is formed,
The wide surface of the lower shield layer exposed through the cut of the top coat layer on the front surface side and the back surface side is made of a resin similar to the resin base material of the shield layer and is for waterproofing to seal the through hole The member is brought into close contact with the wide surface of the lower shield layer exposed through the cut of the top coat layer by insert molding from the front surface side and the back surface side of the flexible wiring substrate to the through hole of the flexible wiring substrate. The corresponding part is integrally molded so as to be entirely wrapped from the periphery, and in the integral molding, the top coat layer of the peripheral part of the shield layer exposed by the cut is integrally formed so as to wrap the waterproof part. A flexible wiring board characterized in that a member is firmly attached to the flexible wiring board. The waterproof member integrally formed with the flexible wiring board has a flange-like flange that is locked by the through hole when the flexible wiring board is passed through the through hole. The flexible wiring board according to claim 1, wherein the flexible wiring board is formed in a circumferential direction . The waterproof member integrally formed with the flexible wiring board has a groove portion to which an elastic ring is attached so that water does not enter through the through hole when the flexible wiring board is passed through the through hole. The flexible wiring board according to claim 1 , wherein the flexible wiring board is formed on a middle outer periphery of the waterproof member in a circumferential direction . The waterproof member integrally formed with the flexible wiring board has a convex portion that prevents water from entering through the through hole when the flexible wiring board is passed through the through hole. The flexible wiring board according to claim 1 , wherein the flexible wiring board is formed in a circumferential direction on a middle belly outer periphery . 5. The flexible wiring board according to claim 1, wherein the resin that is a base material of the shield layer and the waterproofing member is a polyester resin . 6. An electronic device including a first housing and a second housing,
  An electronic apparatus comprising the flexible wiring board according to any one of claims 1 to 5 as a flexible wiring board that electrically connects the first casing and the second casing. Through holes for inserting the flexible wiring board are respectively formed in the first casing and the second casing, and the waterproof member integrally formed with the flexible wiring board is provided on the first casing side. The electronic device according to claim 6, wherein the electronic device is formed at two positions on the flexible wiring board corresponding to a through hole and a through hole on the second housing side.

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