JPH09213168A - Pressure sensitive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive element in which thickness is made to be thin, manufacturing is facilitated, and no occurrence of failure resulting from an assembling error is allowed. SOLUTION: A pressure sensitive element is composed of a pressure sensitive film element 20 formed in the center of the bottom face of the dome-like pushing portion 11 of a film 10. The pressure sensitive film element 20 is composed of an electrode pattern 21 formed on the face of the film 10, a pressure sensitive resistant film 25 formed on the electrode pattern 21, an electrode pattern 27 formed on a location opposite to the electrode pattern 21 on the pressure sensitive resistant film 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane type pressure sensitive element.

[0002]

2. Description of the Related Art In a conventional membrane type switch, as shown in FIG.
Two films 81 and 85 having 87 formed therein and one spacer 88 having a through hole 89 provided at a predetermined position are provided.
The film 8 is provided above and below the spacer 88 with the spacer 88 interposed therebetween.
There is a structure in which 1 and 85 are overlapped and two electrode patterns 83 and 87 are opposed to each other through the through hole 89 at this time.

When the desired electrode pattern 83 of the film 81 is pressed, the electrode pattern 83 comes into contact with the electrode pattern 87 through the through hole 89 and turns it on.

Further, in the conventional membrane type switch, as shown in FIG. 11, electrode patterns 93,
Two films 91 and 95 having 97 formed thereon and one anisotropic pressure-sensitive rubber sheet 98 which is pressed in the thickness direction to turn on only the pressed portion in the thickness direction (to reduce the resistance value). The film 9 is provided above and below the anisotropic pressure-sensitive rubber sheet 98 so that the two electrode patterns 93 and 97 are opposed to each other with the anisotropic pressure-sensitive rubber sheet 98 interposed therebetween.
There is a structure in which 1 and 95 are stacked.

When the desired electrode pattern 93 of the film 91 is pressed, the anisotropic pressure-sensitive rubber sheet 98 directly below the electrode pattern 93 is pressed, and the electrode pattern 93 and the electrode pattern 97 directly below the electrode pattern 93 are pressed. Turns on.

[0006]

However, in each of the above-mentioned membrane type switches, since the structure in which a plurality of members are superposed on each other is used, not only can the thickness of the switch be increased, but further thinning of the switch cannot be achieved, and the distance between the members can be accurately adjusted. Must be positioned and assembled, and the manufacturing thereof is complicated, and there is a possibility that a defect may occur due to an assembly error. Further, the anisotropic pressure sensitive rubber sheet 98 is expensive.

The present invention has been made in view of the above points, and an object thereof is to provide a pressure-sensitive element which can be thinned, is easy to manufacture, and is free from defects due to an assembly error.

[0008]

In order to solve the above-mentioned problems, the present invention has a pressure-sensitive resistance film and a pressure-sensitive resistance film which are pressed in the thickness direction to reduce the resistance value in the thickness direction. A pressure-sensitive film element that has at least two electrode patterns formed on one surface thereof and that changes the resistance value between the two electrode patterns when the pressure-sensitive resistance film is pressed in the thickness direction, A pressure-sensitive element was formed by forming it on a base material.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1A and 1B are diagrams showing a main part of an embodiment in which a pressure-sensitive element according to the present invention is configured as a switch element. FIG. 1A is a plan view and FIG. 1B is a view of FIG. 1A. AA sectional drawing, the same figure (c) is a back view.

As shown in the figure, this pressure-sensitive element is formed by forming a pressure-sensitive film element 20 having a switch function on the lower surface of a dome-shaped pressing portion 11 provided on a flexible film 10. . Hereinafter, each component will be described.

The film 10 is made of a flexible synthetic resin film and has a thickness of 125 μm in this embodiment.
m PET (polyethylene terephthalate) film is used.

The film 10 is provided with a dome-shaped pressing portion 11 which is curved so as to be convex upward. In this embodiment, the dome-shaped pressing portion 11
Has a diameter of 5 mm and a height of 0.5 mm. The dome-shaped pressing portion 11 is molded by heating and pressurizing after forming the pressure-sensitive film element 20 described below on the film 10.

Next, the pressure-sensitive film element 20 has a circular electrode pattern 21 formed in the center of the lower surface of the dome-shaped pressing portion 11 of the film 10 and a circular electrode pattern 21 formed under the electrode pattern 21 so as to cover it. The pressure sensitive resistance film 25 and an electrode pattern 27 formed below the pressure sensitive resistance film 25 at a position facing the electrode pattern 21.

Here, the electrode pattern 21 is formed by screen-printing a silver paste, and the circuit pattern 23 is drawn out from one end thereof. The thickness of the electrode pattern 21 is 10 μm in this embodiment.
m.

The electrode pattern 27 is also formed by screen-printing silver paste, and the circuit pattern 29 is drawn out from one end thereof. The thickness of the electrode pattern 27 is 10 μm in this embodiment.
And

Next, the pressure sensitive resistance film 25 is formed by printing a pressure sensitive material having a function of reducing the resistance value in the thickness direction by pressing in the thickness direction. The thickness of the pressure sensitive resistance film 25 is 40 to 100 μm in this embodiment.
m.

In the pressure-sensitive resistance film 25 according to this embodiment,
An anisotropic pressure-sensitive resistance film whose resistance value changed only in the pressing direction and remained in the insulating state in the other directions was used. As the material of the pressure sensitive resistance film 25, an elastic material mixed with conductive powder is used. Specifically, in this embodiment, silicon rubber is used as the elastic material, carbon powder is used as the conductive powder, and 1.0 part by weight of carbon powder is mixed with 15.0 to 0.2 parts by weight of silicon rubber. Is dissolved in a solvent such as a terpene-based high boiling point solvent. As the carbon powder, granulated carbon black having an average particle size of 1 to 20 μm is used.

The elastic material is not limited to silicone rubber, but other various rubber materials (eg, butadiene rubber, acrylonitrile / butadiene / styrene rubber, etc.) or thermoplastic elastomers (eg, styrene-based thermoplastic elastomer, olefin-based material). A thermoplastic elastomer or the like), a vinyl chloride / vinyl acetate resin material, or a material having various elasticity such as polyethylene can be used.

As the material of the conductive powder, in addition to granulated carbon black, spherical graphite, beaded graphite, scaly graphite,
Flake graphite, earth graphite and the like can be used, and a mixture thereof may be used. Other conductive metal powders may also be used.

In order to operate this pressure-sensitive element, a support member may be arranged below the portion of the film 10 where the pressure-sensitive film element 20 is provided. 2 to 4 are cross-sectional views of essential parts showing examples in which the pressure-sensitive element shown in FIG. 1 is placed on various supporting members.

That is, as shown in FIG. 2, a substrate 31 made of a hard insulating plate may be disposed below the film 10 as a supporting member. If the dome-shaped pressing portion 11 is pressed in this state, the dome-shaped pressing portion 11 is inversely deformed while generating a click feeling, and the pressure-sensitive resistance film 25 is pressed in the thickness direction and the resistance value in the thickness direction becomes small. This turns on between both electrode patterns 21 and 27.

The substrate 31 may be a film-shaped substrate, a metal plate on which an insulating film is formed, or a mold case itself.

When the pressing stroke of the dome-shaped pressing portion 11 is insufficient in the use example shown in FIG. 2, a spacer 33 having a through hole 35 is interposed between the film 10 and the substrate 31 as shown in FIG. Is also good. This makes the spacer 33
The stroke is increased by the thickness of. This spacer 33
May be a film or a coating film.

If a recess 39 is provided in the substrate 37 formed of a mold case as shown in FIG. 4, the stroke is increased by the depth of the recess 39. By further interposing the spacer 33 shown in FIG. 3 in the usage example shown in FIG. 4, the stroke can be further increased.

FIG. 5 is a schematic side sectional view of an essential part showing a usage example of another embodiment of the pressure-sensitive element according to the present invention. The difference between this pressure-sensitive element and the embodiment shown in FIG. 1 is that the dome-shaped pressing portion 11 is not formed on the film 10-2, and the feeling shown in FIG. 1 is directly formed on the lower surface of the flat film 10-2. The point is that a pressure sensitive film element 20-2 similar to the pressure film element 20 is provided.

In the case of this embodiment, the dome-shaped pressing portion 11
As shown in FIG. 5, there is no through hole 35- between the substrate 31-2 and the film 10-2 for actual use.
The spacer 3 is provided with the spacer 33-2 provided therebetween.
A stroke corresponding to the thickness of 3-2 is secured, or a recess 39-2 is provided in the substrate 37-2 as shown in FIG. 6 to secure a stroke.

Next, FIG. 7 is a diagram showing another pressure-sensitive element of the present invention. FIG. 7 (a) is a plan view and FIG. 7 (b) is a rear view.

The pressure-sensitive film element 20-3 attached to this pressure-sensitive element is formed by forming two circuits of the pressure-sensitive film element 20 shown in FIG. 1, and its basic structure is the same as that shown in FIG. is there.

That is, two electrode patterns 21-3 and 3 are formed on the lower surface of the dome-shaped pressing portion 11-3 provided on the flexible film 10-3, and one circular pressure-sensitive resistor is formed on the lower surface. The film 25-3 is formed, and two electrode patterns 27-3 and 3 are formed on the lower surface of the film 25-3 at positions facing the two electrode patterns 21-3 and 3, respectively. From the circuit pattern 23
-3, 3 are drawn out, and two electrode patterns 27-3, 3
From the circuit patterns 29-3 and 3 respectively.

According to this structure, the dome-shaped pressing portion 1
By pressing 1-3, one electrode pattern 21-3
And the electrode pattern 27-3 directly below it are turned on, and at the same time, the other electrode pattern 21-3 and the electrode pattern 27-3 immediately below are also turned on.

8A and 8B are views showing still another pressure-sensitive element of the present invention. FIG. 8A is a plan view, FIG. 8B is a sectional view taken along line BB in FIG. 8A, and FIG. (C) is a rear view.

In this pressure-sensitive element, the pressure-sensitive film element 20-4 is formed on the lower surface of the dome-shaped pressing portion 11-4 provided on the flexible film 10-4.

The pressure-sensitive film element 20-4 is formed by first printing a circular conductive pattern 41-4 at the center of the lower surface of the dome-shaped pressing portion 11-4, for example, by printing silver paste.

Next, one circular pressure sensitive resistance film 25-4 is formed on the lower surface of the conductive pattern 41-4 so as to cover the conductive pattern 41-4. The pressure sensitive resistance film 25-4 is the same as that in each of the above embodiments. And the pressure-sensitive resistance film 2
Two electrode patterns 21-4 and 27-4 are provided on the lower surface of 5-4 and at a position facing the conductive pattern 41-4.
To form Circuit patterns 23-4 and 29-4 are drawn out from both electrode patterns 21-4 and 27-4, respectively.
This constitutes the pressure sensitive film element 20-4.

Then, the pressure-sensitive element is placed on a desired supporting member (not shown) and the dome-shaped pressing portion 11-4 is pressed to press the pressure-sensitive film element 20-4 against the supporting member. The resistance value in the thickness direction of the pressure-sensitive resistance film 25-4 becomes smaller, and the two electrode patterns 21-4 and 27-4 are turned on with the conductive pattern 41-4. Conductive pattern 4
Since 1-4 is a single film, the electrode patterns 21-4 and 27-4 are eventually turned on via the conductive pattern 41-4.

Contrary to this embodiment, the film 10
It is also possible to form two electrode patterns 21-4 and 27-4 on the lower surface of -4, form a pressure sensitive resistance film 25-4 under the electrode patterns 21-4, 27-4, and further form a conductive pattern 41-4 thereunder. Further, the dome-shaped pressing portion 11-4 is not always necessary.

In each of the above embodiments, the pressure sensitive film element 2 is used.
Although 0 (including 20-2 to 4) is provided on the movable member side, conversely, the pressure sensitive film element 20 may be provided on the fixed member side and the movable member may be provided thereon.

FIG. 9 is a side sectional view showing a usage example of another embodiment of the pressure-sensitive element in which the pressure-sensitive film element is thus formed on the fixed side. As shown in the figure, this pressure sensitive film element 20-5
Is formed by forming an electrode pattern 27-5 on the fixed side substrate 31-5, forming a pressure sensitive resistance film 25-5 on the electrode pattern 27-5, and further forming an electrode pattern 21-5 on the electrode pattern 27-5. ing.

Then, for example, if the film 10-5 having the dome-shaped pressing portion 11-5 is arranged on the substrate 31-5 and the dome-shaped pressing portion 11-5 is pressed, both films are generated while a click feeling is generated. The electrode patterns 21-5 and 27-5 are turned on.

As in the above-described embodiments, the dome-shaped pressing portion 11-5 of the film 10-5 can be omitted by interposing a spacer. Also film 10
-5 is not always necessary, and the pressure sensitive film element 20-5 on the substrate 31-5 may be directly pressed, or may be directly pressed by the key top.

In addition to the hard insulating substrate, the substrate 31-5 is
Various modifications similar to those of the above-described embodiments are possible.

If an insulating protective film is formed on the pressure sensitive film element of each of the above embodiments, the pressure sensitive element is protected from mechanical wear.

In each of the above embodiments, the pressure sensitive element according to the present invention is used as a switch element, but the present invention can be configured as a pressing type variable resistance element. That is, since the pressure-sensitive resistance film has a function of changing its resistance value by the pressing force in the thickness direction,
By adjusting the thickness and elastic force of the pressure-sensitive resistive film,
It is also possible to configure a pressure sensitive variable resistance element according to the pressing force.

[0044]

As described in detail above, according to the present invention, since the membrane type pressure sensitive element can be formed on one surface, the thickness can be reduced, and only the pattern forming technique such as printing is used. Since it can be manufactured by, it has an excellent effect that the manufacturing is easy and no assembly error occurs.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a pressure-sensitive element according to an embodiment of the present invention, in which FIG. 1 (a) is a plan view and FIG. 1 (b) is a sectional view taken along line AA of FIG. 1 (a). The same figure (c) is a rear view.

FIG. 2 is a cross-sectional view of essential parts showing an example in which the pressure-sensitive element shown in FIG. 1 is placed on various supporting members.

FIG. 3 is a cross-sectional view of essential parts showing an example in which the pressure-sensitive element shown in FIG. 1 is placed on various supporting members.

FIG. 4 is a cross-sectional view of essential parts showing an example in which the pressure-sensitive element shown in FIG. 1 is placed on various supporting members.

FIG. 5 is a cross-sectional view of essential parts showing a usage example of a pressure-sensitive element according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts showing a usage example of a pressure-sensitive element according to another embodiment of the present invention.

7A and 7B are views showing another pressure-sensitive element of the present invention, in which FIG. 7A is a plan view and FIG. 7B is a rear view.

FIG. 8 is a diagram showing still another pressure-sensitive element of the present invention,
The figure (a) is a top view, the figure (b) is BB of the figure (a).
A sectional view and the same figure (c) are rear views.

FIG. 9 is a sectional view of an essential part showing still another pressure-sensitive element of the present invention.

FIG. 10 is an exploded perspective view showing a conventional membrane type switch.

FIG. 11 is an exploded perspective view showing a conventional membrane type switch.

[Explanation of symbols]

 10 film (base material) 11 dome-shaped pressing part 20 pressure-sensitive film element 21, 27 electrode pattern 25 pressure-sensitive resistive film 41-4 conductive pattern 31-5 substrate (base material)

Claims (3)

[Claims] 1. A pressure-sensitive resistance film that reduces the resistance value in the thickness direction by pressing in the thickness direction, and at least two electrode patterns formed on both surfaces or one surface of the pressure-sensitive resistance film. A pressure-sensitive film element is provided on the base material, the pressure-sensitive film element being configured to change the resistance value between the two electrode patterns when the pressure-sensitive resistance film is pressed in the thickness direction. element. 2. The pressure-sensitive film element includes the pressure-sensitive resistance film,
2. The pressure-sensitive element according to claim 1, wherein at least two electrode patterns formed so as to face each other on both sides of the pressure-sensitive resistive film are laminated on the base material. . 3. The pressure-sensitive film element includes the pressure-sensitive resistance film,
The base material includes a plurality of electrode patterns formed on one surface of the pressure-sensitive resistance film, and a conductive pattern formed on the other surface of the pressure-sensitive resistance film at a position facing the plurality of electrode patterns. The pressure-sensitive element according to claim 1, wherein the pressure-sensitive element is formed by laminating it on top.