JP4166858B2 - Membrane switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a membrane switch formed on the surface of a film-like flexible substrate and provided with a pair of electrodes facing each other.
[0002]
[Prior art]
As disclosed in Japanese Utility Model Publication No. 4-46335, a conventional membrane switch includes a contact made of a pair of electrodes provided facing each other through a predetermined space formed on an insulating sheet, and the contact. Is formed at the end and is composed of a wiring pattern laminated via an insulating sheet. Each of the wiring patterns was formed on an insulating resin film, and the resin film was bonded through an insulating sheet.
[0003]
[Problems to be solved by the invention]
In recent years, electronic devices equipped with membrane switches have become diversified and have come to be used in various places. In addition to electronic devices, products with membrane switches have emerged, and membrane switches are necessary due to their use and convenience. The number of products is increasing.
[0004]
However, although a flexible substrate is used, the substrate of the membrane switch is a thin film and does not have sufficient durability for use in a portion that is deformed by repeated pressing.
[0005]
In addition, an insulator such as an oligomer generated from the resin sheet on the front and back surfaces of the membrane switch may enter the inside or the surface of the opposing electrodes forming the contact, and the current conductivity at the contact may deteriorate.
[0006]
The present invention has been made in view of the above-described conventional problems, and has an object to provide a membrane switch having a highly deformable contact having a good conductivity and a wiring between the contacts. is there.
[0007]
[Means for Solving the Problems]
The membrane switch of the present invention includes a pair of resin films such as insulating polyethylene naphthalate, an upper electrode wiring pattern formed on one of the resin films and having electrodes at a plurality of ends, and the other of the resin films. And a lower electrode wiring pattern having electrodes at a plurality of ends, and an insulating sheet sandwiched between the upper electrode wiring pattern and the lower electrode wiring pattern. Through holes are formed at positions of the insulating sheet facing the electrodes, the electrodes on the pair of resin films face each other with the through holes interposed therebetween, and the electrodes facing each other by pressing from outside. It is a membrane switch which is provided so as to be able to come in contact with and separate from and constitutes a switch. The wiring patterns except for the electrodes are provided in parallel to each other on the planes of the resin films, and the upper electrode wiring pattern formed on one of the pair of resin films includes: The insulating sheet is laminated, the other resin film of the pair of resin films is laminated, and the insulating sheet is laminated on the lower electrode wiring pattern formed on the other of the pair of resin films. Further, one resin film of the pair of resin films is laminated, and in this state, each of the wiring patterns excluding the electrodes is provided at a position different from each other and the projection positions do not overlap each other . . Further, a pair of switches are provided respectively branched from the electrode wiring patterns on both sides, and the wiring pattern between each pair of adjacent switches is curved in a U shape on each plane. The pair of resin films and insulating sheets formed and provided with the respective wiring patterns are disposed between the portions where the respective switches are provided in the plane so as to surround the wiring patterns along the wiring pattern. It is formed in a U-shaped curved shape.
[0008]
Even if an external force is applied to the insulating resin film by bending the pair of insulating resin films formed with the wiring patterns and the bent shape of the wiring patterns in a U shape, It deforms at the bent portion and follows the direction of the external force, so that an excessive force is not applied to each wiring pattern.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The membrane switch according to the embodiment of the present invention is made of an insulating resin film 10 made of polyethylene naphthalate (PEN) as shown in FIG. 1, and an upper electrode wiring pattern 12 is formed on the surface thereof. A lower electrode wiring pattern 16 is formed on the surface of the other resin film 14 facing the resin film 10. A circular upper electrode 18 and a lower electrode 20 are formed at each end of a plurality of predetermined locations provided in each wiring pattern 12, 16. An insulating sheet 22 of polyethylene terephthalate (PET) is interposed between the wiring patterns 12 and 16. The insulating sheet 22 is formed with a plurality of through holes 24 at predetermined end portions, and the upper electrode 18 and the lower electrode 20 are positioned to face each other with the through holes 24 interposed therebetween as shown in FIG. A thin film switch 26 is formed.
[0010]
Each wiring pattern 12, 16 connected to each electrode 18 and 20, as shown in FIG. 1, each in a shape curved in U-shape on the same plane, the resin film 10, 14 and the insulating sheet 22 also the wiring pattern It is formed in a shape curved in a U shape along the shape of 12,16.
[0011]
The wiring patterns 12 and 16 are provided in parallel to each other so that the projection positions do not overlap with the surfaces of the resin films 10 and 14 facing each other. Further, the insulating sheet 22 provided between the wiring patterns 12 and 16 has a space 28 communicating with the through hole 24 between the electrodes 18 and 20, and the end of the space 28 is connected to another circuit. In the vicinity of the ends of the wiring patterns 12, 16 connected to the air holes 30, the air holes 30 provided in the resin film 10 communicate with each other.
[0012]
Each of the wiring patterns 12 and 16 is provided so as to cover the entire surface other than the conductive paint layer 32 containing a metal such as silver or copper and the surface where the conductive paint layer 32 contacts the resin films 10 and 14. A carbon paint layer 34 is laminated. As a result, the carbon paint layer 34 serves as a contact point for the electrodes 18 and 20 in the switch 26.
[0013]
Here, the polyethylene naphthalate forming the resin films 10 and 14 has good conductivity without the low polymer oligomers entering the inside or the surface of the wiring patterns 12 and 16 formed on the surface thereof. Maintain for a long time. Moreover, polyetherimide, a polyimide, etc. can be used as a resin film which does not discharge | release an oligomer similarly to polyethylene naphthalate. These resins are currently more expensive than polyethylene naphthalate, but can be used due to the following various cost reductions.
[0014]
Each wiring pattern 12, 16 of this embodiment, as shown in FIG. 1, each pair of switches 26 branches on either side of each of the wiring patterns 12 and 16 are provided, that during the U-shaped coplanar The resin films 10 and 14 and the insulating sheet 22 are also formed in a U-shaped curve along the shape of the wiring patterns 12 and 16. Therefore, when both the left and right ends of the resin film 10 in FIG. 1 are pulled, the resin films 10 and 14 and the insulating sheet 22 are deformed, and the wiring patterns 12 and 16 follow this and the distance between both ends is extended. Thereby, force does not concentrate on any member, and the resin films 10 and 14 and the wiring patterns 12 and 16 are not damaged.
[0015]
Further, since air in the through-hole 24 provided in the switch 26 by the contact and separation of the switch 26 passes through the space 28 and is discharged or infiltrated from the air hole 30, the membrane switch is securely connected, and the switch 26 is also damaged. Absent.
[0016]
Since this membrane switch is rich in deformability, it is installed in a place where it is deformed by pressing the seat of an automobile, for example, and when a person sits on the seat, the switch 26 is connected and used as a sensor for detecting the presence of a person. Can do. When a person is seated on the seat, the seat is deformed by its weight, and the resin films 10 and 14 and the insulating sheet 22 follow the deformation to reliably detect the presence of a person without impairing the seating comfort of the seat. can do.
[0017]
The membrane switch of the present invention is not limited to the above embodiment, and the wiring pattern and the shape of the electrode can be appropriately changed. In addition, other resin films that do not generate oligomers can be used as long as they can obtain good conductivity.
[0018]
【The invention's effect】
The membrane switch of the present invention can be bent in the same plane to form a resin film and a wiring pattern, and can be freely deformed against an external force to prevent breakage. In addition, by using polyethylene naphthalate for the insulating resin film, it is possible to prevent the entry of insulators such as oligomers into the electrode, ensure good continuity for a long period of time, and provide a high-quality membrane switch with a simple structure. It is possible to provide.
[Brief description of the drawings]
FIG. 1 is a plan view showing a membrane switch according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 showing the switch of the membrane switch of this embodiment.
3 is a cross-sectional view taken along the line BB in FIG. 1 showing a wiring pattern of the membrane switch of this embodiment.
[Explanation of symbols]
10, 14
Resin film 12 Upper electrode wiring pattern 16 Lower electrode wiring pattern 18 Upper electrode 20 Lower electrode 22 Insulating sheet 24 Through hole 26 Switch 28 Space 30 Air hole 32 Conductive paint layer 34 Carbon paint layer

Claims (2)

A pair of insulating resin films, an upper electrode wiring pattern formed on one end of the resin film and having electrodes at a plurality of ends, and formed on the other end of the resin film and having electrodes at a plurality of ends. A wiring pattern for the lower electrode; and an insulating sheet sandwiched between the wiring pattern for the upper electrode and the wiring pattern for the lower electrode, and a through hole is formed at a position facing the electrode of the insulating sheet. In the membrane switch in which the electrodes on the pair of resin films face each other with the through hole interposed therebetween, and the electrodes facing each other by pressing from the outside are provided so as to be able to contact and separate,
The wiring patterns except for the electrodes are provided in parallel to each other on the planes of the resin films, and the upper electrode wiring pattern formed on one of the pair of resin films includes: The insulating sheet is laminated, the other resin film of the pair of resin films is laminated, and the insulating sheet is laminated on the lower electrode wiring pattern formed on the other of the pair of resin films. Further, one resin film of the pair of resin films is laminated, and in this state, each of the wiring patterns excluding the electrodes is provided in a position different from each other and provided so that the projection positions do not overlap each other. A pair of switches each branching from the electrode wiring pattern to both sides is provided, and the pair of switches adjacent to each other The line pattern is formed in a U-shaped curved shape on each of the planes, and the pair of resin films and insulating sheets provided with the wiring patterns surround the wiring patterns along the wiring pattern. Thus, the insulating sheet formed between the wiring patterns is formed in a U-shaped curved shape between the portions where the pair of switches are provided in the plane. A membrane having a space communicating with a hole, and an end of the space communicates with an air hole provided in the resin film in the vicinity of an end of a wiring pattern connected to another circuit switch.   2. The membrane switch according to claim 1, wherein the insulating resin film is polyethylene naphthalate.

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