JPH1064363A - Membrane switch - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the withstand voltage performance by making it difficult to conduct electricity between an upper contact portion and a lower contact portion. An upper membrane and a lower membrane are provided.
2 is provided with an upper contact portion 21 and a lower contact portion 22 respectively.
Are made different in diameter to increase the separation distance between their outer edge portions (edge portions).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch which performs a switching operation by contacting contact portions provided on upper and lower membranes.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional example of this type of membrane switch. The illustrated membrane switch 40 has an upper membrane 31 and a lower membrane 32 having flexibility, and the upper membrane 11 and the lower membrane 1 are flexible.
2, a predetermined wiring pattern is formed (not shown), and a disc-shaped upper contact portion 41 and a lower contact portion 42 having the same diameter as switches are provided so as to face each other. A resist layer 14 is formed around the contact portions 41 and 42 so as to be a part of a spacer described later.

The upper membrane 11 and the lower membrane 12 are separated from each other by a fixed distance by a spacer disposed therebetween. The spacer is composed of the resist layer 14, the double-sided tape 15, the sheet-shaped spacer 13, the double-sided tape 15, and the resist layer 14 in this order from the upper side. A switching gap hole 16 having the same diameter for contact (ON) is formed.

[0006] The membrane switch 40 having such a configuration is used.
When the upper contact portion 41 of the upper membrane 11 is pressed down by a key or the like, the upper membrane 11 bends and the upper contact portion 41
(ON), and when the pressing is released, the upper contact portion 41 returns to the original position due to the elasticity of the upper membrane 11 (OFF).
To).

[0005]

In the above-described membrane switch, the distance between the upper contact point and the lower contact point is extremely short, and is usually 0.5 mm or less.

Therefore, even if the upper contact portion and the lower contact portion are separated (OFF state) as shown in FIG.
And the lower contact portion 42 may be energized, and sufficient withstand voltage performance may not be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. It is an object of the present invention to make it difficult to conduct electricity between an upper contact portion and a lower contact portion, and to achieve a sufficient withstand voltage performance. To provide a membrane switch adapted to obtain a membrane switch.

[0008]

To achieve the above object, a membrane switch according to the present invention basically comprises:
An upper membrane and a lower membrane having flexibility opposed to each other via a spacer having a gap hole for switching, and an upper contact portion and a lower contact which serve as switches in the upper membrane and the lower membrane, respectively. A contact portion is provided, and when the upper contact portion of the upper membrane is depressed, the upper membrane is bent so that the upper contact portion contacts the lower contact portion.

The size of the upper contact portion and the lower contact portion in a plan view is different from each other.

In a preferred aspect, the upper contact portion and the lower contact portion are formed in a disk shape, and have different diameters.

In another preferred embodiment, the spacer comprises a sheet spacer, and a pair of upper and lower double-faced tapes disposed between upper and lower surfaces of the sheet spacer and the upper and lower membranes. The diameter of the gap for switching provided in the sheet-shaped spacer is smaller than the diameter of the gap for switching of the double-sided tape, and the edge of the gap is the upper contact portion or the lower edge. It is made to be located near the contact portion.

In general, when current flows between two separated objects, current flows between the shortest distance portions of the two objects. In a membrane switch, when current flows between the upper contact portion and the lower contact portion, Since the current flows between the outer edges (edges) of the upper and lower contacts, the longer the distance between the outer edges (edges) of the upper and lower contacts, the higher the withstand voltage performance.

Therefore, if the upper contact portion and the lower contact portion have different sizes in plan view as in the membrane switch of the present invention, the distance between the outer edge portions (edge portions) of the upper contact portion and the lower contact portion can be reduced. Is longer than a conventional one in which the upper contact portion and the lower contact portion have the same size in plan view, and as a result, the withstand voltage performance is improved.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a membrane switch according to the present invention. In the drawing, portions corresponding to the respective portions of the above-described conventional membrane switch 40 are denoted by the same reference numerals and detailed description thereof will be given. The description will be omitted, and the differences will be mainly described below.

The membrane switch 10 shown in FIG.
Similarly to the conventional one, it has an upper membrane 31 and a lower membrane 32 having flexibility, and the upper membrane 11 and the lower membrane 12 are fixed by a spacer arranged therebetween. They are separated by a distance. The spacers are, in order from the top, the resist layer 14,
Double-sided tape 15, sheet-shaped spacer 13, double-sided tape 1
5, a resist layer 14, in which a switching gap hole 16 having the same diameter is formed.

In the membrane switch 10 of the present embodiment, the upper contact portion 21 provided on the upper membrane 11 and the lower contact portion 22 provided on the lower membrane 12 are both disc-shaped and have a common central shaft. Although they are arranged to face each other on the line, the diameter of the upper contact portion 21 is smaller than that of the lower contact portion 22.
Are different from each other in size in plan view.

The membrane switch 40 having such a configuration
When the upper contact portion 21 of the upper membrane 11 is pressed down with a key or the like, the upper membrane 11 bends and the upper contact portion 21
Contact (ON), and when the push-down is released, the upper contact portion 21 returns to the original position due to the elasticity of the upper membrane 11 (OFF
Do).

Here, as described above, in the membrane switch, when current flows between the upper contact portion and the lower contact portion, the current flows between the outer edges (edge portions) of the upper contact portion and the lower contact portion. The longer the distance between the outer edges (edges) of the upper contact and the lower contact, the higher the withstand voltage performance.

Therefore, in the case where the diameters of the upper contact portion 21 and the lower contact portion 22 are different from each other as in the membrane switch 10 of the present embodiment, the upper contact portion 21 and the lower contact portion 2
The distance between the outer edges (edge portions) of the upper contact portion 21
And the lower contact portion 22 has the same diameter as that of the conventional one, and as a result, it becomes difficult to conduct electricity between the upper contact portion 21 and the lower contact portion 22, and the withstand voltage performance is improved.

FIG. 2 shows a second embodiment of the membrane switch according to the present invention. In the figure, the parts corresponding to those of the above-mentioned conventional membrane switch 40 are denoted by the same reference numerals, and the details thereof are shown. Detailed description is omitted, and the following description focuses on the differences.

The membrane switch 3 of the second embodiment
0, the diameter of the upper contact portion 31 is larger than the diameter of the lower contact portion 32. However, the diameters of the upper contact portion 31 and the lower contact portion 32 are the same as those of the membrane switch 10 of the first embodiment. The diameter of each of the upper contact portion 21 and the lower contact portion 22 is slightly larger.

In addition, the spacer switch is different from the membrane switch 10 of the first embodiment.
That is, in the membrane switch 30 of the present embodiment, the diameter of the switching gap 17 provided in the sheet-shaped spacer 13 is smaller than the diameter of the switching gap 16 of the double-sided tape 15 and the resist layer 14. Then, the edge 17 a of the gap hole 17 is located near the upper contact portion 31.

In the membrane switch 30 having such a configuration, when a current flows between the upper contact portion 31 and the lower contact portion 32, a current flows from the outer edge of the upper contact portion 31 to the inner edge of the sheet-like spacer 13. As a result, the current flows to the outer edge of the lower contact portion 32 (or in the opposite direction), so that the current flows directly between the outer edges of the contact portions 21 and 22 as in the first embodiment. , Upper contact part 31 and lower contact part 3
2 have the same effect as being separated by a greater distance, they are more difficult to conduct, and the withstand voltage performance is further improved.

The above-described embodiment is merely an example, and the structure of each part, particularly the dimensions of the contact part and the spacer,
Needless to say, the shape, structure, and the like can be appropriately changed.

[0026]

As will be understood from the above description, in the membrane switch of the present invention, the upper contact portion and the lower contact portion have different sizes in plan view.
The distance between the outer edges (edges) of the upper contact and the lower contact is longer than that of the conventional contact having the same size in plan view of the upper contact and the lower contact. This has an excellent effect that the withstand voltage performance can be enhanced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a membrane switch according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the membrane switch according to the present invention.

FIG. 3 is a sectional view showing an example of a conventional membrane switch.

[Explanation of symbols]

 10, 20 membrane switch 11 upper membrane 12 lower membrane 13 sheet spacer 14 resist layer 15 double-sided tape 16, 17 gap hole 21, 31, upper contact part 22, 32 lower contact part

Claims (3)

[Claims] A flexible upper membrane and a lower membrane opposed to each other via a spacer having a switching gap formed therein, and each of the upper membrane and the lower membrane serves as a switch. A membrane switch provided with an upper contact portion and a lower contact portion, wherein the upper contact portion of the upper membrane is depressed, whereby the upper membrane is bent so that the upper contact portion contacts the lower contact portion. 3. The membrane switch according to claim 1, wherein the upper contact portion and the lower contact portion have different sizes in plan view. 2. The membrane switch according to claim 1, wherein the upper contact portion and the lower contact portion are disk-shaped and have different diameters. 3. The method according to claim 1, wherein the spacer is a sheet-like spacer,
It consists of a pair of upper and lower double-faced tapes disposed between the upper and lower surfaces of the sheet-shaped spacer and the upper membrane and the lower membrane, and the diameter of the switching gap hole provided in the sheet-shaped spacer is 3. The double-sided tape, wherein the diameter of the gap for switching is smaller than the diameter of the gap, and the edge of the gap is located near the upper contact portion or the lower contact portion. Membrane switch described in.