JP2008135705A - Sealing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure which has superior hermetic sealing properties and can be manufactured at low cost, by surely integrating a flexible wiring board and a sealing member, without causing rubber burrs in integrally molding the sealing member on the flexible wiring board. <P>SOLUTION: The sealing structure comprises a housing through which the flexible wiring board 1 penetrates, and a sealing member 3 molded integrally with the flexible wiring board 1 and hermetically sealing a gap between the housing and the flexible wiring board 1. The flexible wiring board 1 is constituted of a base substrate, constituted of an elastic material, a conductive printed wiring layer 12 formed on the surface of the base substrate, and a cover film for covering the surface of the printed wiring board. Dummy printed wiring boards 14 are provided so that the printed wiring board exist over the overall direction of the width of the base substrate, in a region where the sealing member 3 is integrated with the flexible wiring board 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a seal structure.
More particularly, the present invention relates to a seal structure that provides a waterproof structure for electronic devices and connectors.

Recently, waterproof connectors used in electronic devices such as mobile phones and wire harnesses for automobiles have been required to have a high waterproof function at the same time as miniaturization has progressed.
In order to provide a waterproof function to an electronic device composed of a plurality of spaces, it is necessary to provide airtightness to the housings constituting the spaces and to electrically connect the spaces with a flexible substrate or the like.
In this case, a terminal is provided on the wall surface of the housing that partitions each space, and a wiring material is connected between these terminals, or a gap formed between the wiring material and the housing is passed through the wall surface of the housing with an adhesive or the like. A method of filling was proposed.
However, the aspect in which the terminals are provided on the wall surface of the housing has a problem in that the equipment becomes large.
The method of filling the gap formed between the wiring member and the housing with an adhesive or the like has caused a problem that it is difficult to disassemble and reassemble.

Therefore, as shown in FIGS. 7 and 8, a mode has been proposed in which a sealing member is integrally formed on a flexible wiring board (Japanese Patent Laid-Open Nos. 2003-142836 and 2004-214927).
In the embodiment shown in FIG. 7, a frame-shaped seal member 301 corresponding to the shape of each housing (not shown) is integrally formed with the flexible wiring board 100.
The flexible wiring board 100 extends through each seal member 301, and an electronic component is mounted in a region surrounded by each seal member 301.

In the embodiment shown in FIG. 8, a bush-shaped seal member 303 is integrally formed with the flexible wiring board 100.
The seal member 303 is attached to an insertion hole provided in each housing (not shown).
And the connector 304 provided in the both ends of the flexible wiring board 100 electrically connects with the electrical component in a housing.
Furthermore, as shown in FIG. 1, the thing of the aspect which combined FIG. 7 and FIG. 8 was proposed.
That is, a frame-shaped seal 31 is integrally formed on one side of the flexible wiring board 1, and a bush-shaped seal 32 is integrally formed on the other side.

However, as shown in FIG. 6, which is a cross section taken along the line AA of FIG.
Usually, the flexible wiring board 1 has the following structure.
That is, a printed wiring layer 12 (circuit pattern) made of copper foil is bonded and fixed to one surface of a base substrate 11 made of an elastic material such as polyimide, polyamide, polyester, or liquid crystal polymer.
Next, a cover film 13 made of the same material as the elastic material used for the base substrate 11 is formed on the surface of the printed wiring layer 12 in order to protect the surface.
As a result, the printed wiring layer 12 is sandwiched between the base substrate 11 and the cover film 13.
The printed wiring layer 12 is usually narrower than the width of the base substrate 11.
In FIG. 6, the width of the printed wiring layer 12 is 1/3 or less of the base substrate 11.
As a result, when molding pressure is applied when the sealing member 3 is integrally formed on the flexible wiring board 1, the portion where the printed wiring layer 12 is not present is deformed thinner than the portion where the printed wiring layer 12 is present.
For this reason, as shown in FIG. 9, gaps 2 and 2 are inevitably generated between the molding die 50 and the flexible wiring board 1, which may cause leakage of the rubber material filled during molding, It caused a problem to occur.
As a result, there has been a problem that the flexible wiring board 1 and the seal member 3 cannot be joined properly.
FIG. 9 shows that the portion outside the molding region of the seal member 3 is perpendicular to the flexible wiring substrate 1 when the molding die 50 used when the sealing member 3 is integrally molded with the flexible wiring substrate 1 is closed. The state cut | disconnected in the direction to perform is shown.

JP 2003-142836 A JP 2004-214927 A

In view of the above, the present invention eliminates the occurrence of rubber burrs when the sealing member is integrally formed on the flexible wiring board, and the flexible wiring board 1 and the sealing member 3 can be reliably integrated. An object of the present invention is to provide a seal structure that has good performance and can be manufactured at low cost.

In order to achieve the above object, in the present invention, a seal comprising a housing through which a flexible wiring board is inserted, and a seal member that is integrally formed with the flexible wiring board and seals a gap between the housing and the flexible wiring board. In the structure, the flexible wiring board includes a base substrate made of an elastic material, a conductive printed wiring layer formed on a surface of the base substrate, and a cover film covering the surface of the printed wiring layer. In the region where the seal member is integrated with the flexible wiring board, a dummy printed wiring layer is provided so that the printed wiring layer exists in the entire width direction of the base substrate.

The present invention has the following effects.
According to the seal structure of the invention of the first aspect, the seal member and the flexible wiring board can be reliably integrated as a whole, and rubber burrs are not generated during molding.

Moreover, according to the seal structure of the invention described in claim 2, the influence on the printed wiring layer can be reduced.
Furthermore, according to the seal structure of the invention of the third aspect, the gap generated between the molding die and the flexible wiring board can be further reduced.
Furthermore, according to the seal structure of the invention described in claim 4, it is possible to suppress the occurrence of rubber burrs over the entire surface of the mold.

Furthermore, according to the seal structure of the invention described in claim 5, it can be used for many purposes.
Furthermore, according to the seal structure of the invention described in claim 6, the waterproof performance of the entire region including the mating surface of the housing can be improved.
Furthermore, according to the seal structure of the invention described in claim 7, the seal between the insertion hole provided in the housing and the flexible wiring board can be reliably performed.
Furthermore, according to the seal structure of the invention described in claim 8, it is possible to cope with various housing shapes.

Hereinafter, the best mode for carrying out the present invention will be described.
The best mode for carrying out the invention will be described with reference to FIGS. 1 to 5 and FIG.
FIG. 1 is a view showing an example of a seal structure to which the present invention is applied, FIG. 2 is a first embodiment of the present invention, and FIG. 3 shows the same parts as in FIG. FIG. 3 is a sectional view taken along line BB in FIG. 2.

In FIG. 1, seal members 3 and 3 having different shapes are integrally formed at both ends of a flexible wiring board 1.
The upper seal member 3 in the figure is a frame-shaped seal 31 that seals the gap between the housing and the flexible wiring board 1 at the same time. The lower seal member 3 in the figure is inserted through the housing. A bush-shaped seal 32 is provided to seal the gap between the hole and the flexible wiring board 1.

The flexible wiring board 1 has the following structure.
That is, the printed wiring layer 12 (circuit pattern) made of copper foil is bonded and fixed to one surface of the base substrate 11 made of an elastic material such as polyimide, polyamide, polyester, or liquid crystal polymer.
Next, a cover film 13 for protecting the surface is formed on the surface of the printed wiring layers 12 and 12.
The cover film 13 is made of the same material as the elastic material used for the base substrate 11.
As a result, the printed wiring layer 12 is sandwiched between the base substrate 11 and the cover film 13.
Then, as shown in FIG. 2, in a place where the sealing member 3 and the flexible wiring board 1 are integrally formed, a dummy print is provided so as to sandwich the printed wiring layer 12 separately from the regular printed wiring layer 12. Wiring layers 14 and 14 are arranged.
The combined width of the lint wiring layer 12 and the dummy printed wiring layers 14 and 14 is close to the width of the flexible wiring board 1.
The lengths of the dummy printed wiring layers 14 and 14 are substantially equal to the contact surface of the mold.
Therefore, as shown in FIG. 10, even if the flexible wiring board 1 is disposed in the molding die 50, a gap 2 is generated between the die 50 and the flexible wiring board 1 as in the prior art (FIG. 9). There is nothing.
FIG. 10 is the same as FIG. 9 and is out of the molding region of the seal member 3 in a state in which the molding die 50 used when the seal member 3 is integrally molded with the flexible wiring board 1 is closed. The state which cut | disconnected the location in the direction orthogonal to the flexible wiring board 1 is shown.

Next, a second embodiment of the present invention will be described with reference to FIGS.
5 is a cross-sectional view taken along the line CC of FIG.
The difference from the first embodiment is that the dummy printed wiring layer 14 is formed integrally with the printed wiring layer 12.
Others are the same as the first embodiment.
The seal members 3 and 3 are made of a rubber-like elastic material such as acrylic rubber, fluorine rubber, or EPDM, but self-adhesive liquid rubber is preferable.

Both the frame-shaped seal 31 and the bush-shaped seal 32 are baked and integrated on the flexible wiring board 1 using a mold.
Both the sealing members 3 and 3 seal the gap between the mating surfaces of the housing and the gap between the insertion hole provided in the housing and the flexible wiring board 1.
The flexible wiring board 1 may have a multilayer structure, and the present invention is particularly effective in the multilayer structure flexible wiring board 1.

The housing may be a mobile phone frame or a connector housing.
In addition to the frame-shaped seal 31 and the bush-shaped seal 32, the seal member 3 can have various shapes.
Further, the number of the sealing members 3 attached to the flexible wiring board 1 is two in the embodiment, but may be three or more according to the structure of the target device.

The present invention is not limited to the best mode for carrying out the invention described above, and various other configurations can be adopted without departing from the gist of the present invention.

It is a top view which shows an example of the seal structure to which this invention is applied. It is a fragmentary top view of the seal structure concerning the present invention. It is BB sectional drawing of FIG. It is a fragmentary top view of the other seal structure concerning the present invention. It is CC sectional drawing of FIG. It is AA sectional drawing of FIG. 1 which concerns on a prior art example. It is a top view which shows the seal structure which concerns on a prior art example. It is a top view of the seal structure concerning other conventional examples. It is sectional drawing which shows the relationship between the shaping die concerning a prior art example, and a flexible wiring board. It is sectional drawing which shows the relationship between the shaping | molding die concerning this invention, and a flexible wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flexible wiring board 2 ... Gap 3 ... Seal member 11 ... Base board 12 ... Printed wiring layer 13 ... Cover film 31 ... Frame shape seal 32 ... Bush Shape seal

Claims (8)

  A sealing structure comprising a housing through which a flexible wiring board (1) is inserted and a sealing member (3) which is integrally formed with the flexible wiring board (1) and seals a gap between the housing and the flexible wiring board (1). In the body, the flexible wiring board (1) includes a base substrate (11) made of an elastic material, a conductive printed wiring layer (12) formed on the surface of the base substrate (11), and the printed wiring layer. And a cover film (13) covering the surface of (12), and in a region where the sealing member (3) is integrated with the flexible wiring board (1), the width direction of the base substrate (11) A sealing structure characterized in that a dummy printed wiring layer (14) is provided so that the printed wiring layer (12) is present throughout.   The seal structure according to claim 1, wherein the dummy printed wiring layer (14) is provided separately from the printed wiring layer (12).   The seal structure according to claim 1, wherein the dummy printed wiring layer (14) is provided integrally with the printed wiring layer (12).   The size of the dummy printed wiring layer (14) in the length direction is substantially the same as a contact surface of a mold when the seal member (3) is formed. The seal structure according to any one of claims 1 to 3.   The sealing structure according to any one of claims 1 to 5, wherein the flexible wiring board (1) has a multilayer structure.   The seal structure according to any one of claims 1 to 4, wherein the seal member (3) is a frame-shaped seal (31) for sealing the mating surface (4) of the housing.   The seal structure according to any one of claims 1 to 4, wherein the seal member (3) is a bush-shaped seal (32) mounted in an insertion hole (5) provided in the housing.   The seal structure according to any one of claims 1 to 4, wherein the seal member (3) is a combination of the frame-shaped seal (31) and the bush-shaped seal (32).

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