JPH0721877A - Membrane switch with rubber cap - Google Patents

Abstract

PURPOSE:To provide a membrane switch with rubber cap capable of surely fixing a rubber cap to a membrane sheet and reducing the manufacturing cost. CONSTITUTION:A rubber cap 3 has a dome part 3a internally having a continuing electrode 5 mounted thereon, and a protruding part 3c protruding outward from the lower end part of the dome part 3a. The rubber cap 3 is fixed to a membrane sheet 2 by nipping the protruding part 3c between a fixed sheet 9 having an opening part 9a for inserting the dome part 3a of the rubber cap 3 through and the membrane sheet 2 having a comb-tooth electrode 1 mounted thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch with a rubber cap used in various electronic devices.

[0002]

2. Description of the Related Art A membrane switch is a typical thin switch input device for electronic equipment such as a personal computer and a keyboard for word processors. The most basic structure of a membrane switch is a switch structure consisting of a pair of counter electrodes with a spacer interposed.A dome-shaped rubber cap or a spring switch is provided above the counter electrodes for the purpose of giving a click feeling. It is known that it is installed.

Further, as a membrane switch having a similar purpose, instead of the above-mentioned counter electrode, as shown in FIG. 4, a comb electrode 1 having a plurality of contacts 1a, 1a ,.
A single rubber cap 3 for each comb-teeth electrode 1 is fixed by an adhesive material 4 on the membrane sheet 2 provided with 1, ..., And a contact point 1a of the comb-teeth electrode 1 is formed by a conducting electrode 5 provided inside the rubber cap 3. There is a type of conducting a switching operation by conducting. This type of membrane switch 6 has advantages of low cost and thinness.

Further, instead of the above-mentioned single rubber cap, there is also a type using a switch integrally formed with a plurality of rubber caps as shown in FIG.
In this case, the integrated rubber cap 7 is arranged on the membrane sheet 2, and the fixing boss 7a formed on the rubber cap 7 is provided with the hole 2a formed on the membrane sheet 2.
They are fitted to each other to fix each other. This type of membrane switch 8 has advantages that the number of assembling steps can be reduced and the fixing stability is high.

[0005]

However, the conventional membrane switch with a rubber cap has the following problems for each of the above-mentioned two types of switches.

First, in the type using a single rubber cap, as shown in FIG. 4, the rubber cap 3 is fixed to the membrane sheet 2 by using the adhesive material 4, and the rubber cap 3 is fixed through the small area under the rubber cap 3. Since the adhesive 3 and the adhesive 3 are only in contact with each other, the rubber cap 3 may easily come off the membrane sheet 2 as the membrane switch 6 is repeatedly used.

Further, when the rubber cap 3 is attached in the manufacturing process, it is difficult to position the rubber cap 3 and, at the same time, when the actual position of the rubber cap 3 deviates from the predetermined position, the adhesive material 4 is attached. There is a problem that the contact area of the lower surface of the rubber cap 3 is reduced and the rubber cap 3 is easily separated from the membrane sheet 2.

On the other hand, the type using the integrated rubber cap 7 requires more resin material to be used for the rubber cap than the case of using the single rubber cap 3, but an appropriate elastic force as the rubber cap is required. The resin material that can be obtained is relatively expensive, which causes a problem of high material cost.

Further, in the case where the position and arrangement of the switches are different depending on various electronic devices, a mold for manufacturing the rubber cap 7 must be individually prepared, and in addition to the above material factors, The manufacturing of the mold has also been a factor of high cost.

The present invention has been made to solve the above problems, and provides a membrane switch with a rubber cap, which can surely fix the rubber cap to the membrane sheet and reduce the manufacturing cost. The purpose is to

[0011]

In order to achieve the above-mentioned object, the membrane switch with a rubber cap of the present invention is formed in a dome shape, and a rubber cap having a first electrode installed on the inner surface thereof has an upper surface. In the membrane switch with a rubber cap, which is fixed so that the first and second electrodes face each other above the membrane sheet on which the second electrode is installed, the rubber cap is a dome-shaped rubber cap body. And a protrusion that protrudes outward from the lower end of the rubber cap body, and is fixed on the membrane sheet by a fixing sheet, and the fixing sheet has an opening. The rubber cap is arranged such that the rubber cap body is projected upward from the opening, and the projection is Sandwiched between the constant sheet and the membrane sheet, and is characterized in that it is fixed.

[0012]

According to the membrane switch with a rubber cap of the present invention, the rubber cap is fixed to the membrane sheet by sandwiching the protruding portion of the rubber cap between the fixing sheet and the membrane sheet.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS.
Will be explained. FIG. 1 is a diagram showing constituent elements of a membrane switch with a rubber cap, in which reference numeral 2 is a membrane sheet, 3 is a rubber cap, and 9 is a fixing sheet. The membrane switch 10 is used for a keyboard of a personal computer, for example, and switches corresponding to a plurality of key mounting positions are integrally formed.

The membrane sheet 2 is made of a thin resin sheet, and the comb-teeth electrodes (second electrodes) 1 are installed at a plurality of positions where a switch is to be formed. The comb-tooth electrode 1 has four contacts 1a, 1a, ..., And the switching operation is performed depending on the conduction state of two adjacent contacts 1a, 1a.

The rubber cap 3 is made of rubber and has a dome portion (rubber cap body) 3a formed in the shape of a hollow hemisphere, and a pressing portion 3b slightly protruding upward from the dome portion 3a. Along with the entire outer circumference of the dome portion 3a, the protruding portion 3 protruding outward is provided at the lower end.
c is provided and is elastically deformable. Also,
On the inner surface of the dome portion 3a, a conductive electrode made of carbon (first
Electrode 5) is installed.

The fixed sheet 9 is formed by molding a film having an adhesive material attached to one side thereof to the same size as the membrane sheet 2. As shown in FIG. 3, the rubber cap 3 is aligned with the switch forming position. Are formed with openings 9a, 9a, ... Having a diameter that matches the outer diameter of the dome portion 3a.

Next, when assembling the membrane switch 10 consisting of the above-mentioned constituents, first, the fixing sheet 9 is arranged with its adhesive surface facing upward, and both ends are fixed by jigs and slightly moved. Apply tensile force. Then, the rubber cap 3 is placed from above so that the openings 9a of the fixed sheet 9 and the dome portion 3a of the rubber cap 3 are fitted together. Then, the dome portion 3a of the rubber cap 3 projects downward from the opening 9a of the fixed sheet 9 and the protruding portion 3 of the rubber cap 3
Since c is adhered to the adhesive surface of the fixing sheet 9, when the membrane sheet 2 is adhered while aligning the membrane sheet 2 with the fixing sheet 9 to which the rubber cap 3 is adhered, the membrane switch 10 Assembly will be completed.

FIG. 2 is a view showing the state after the membrane switch is assembled. The membrane switch 10 is normally in the off state, but when the pushing portion 3b of the rubber cap 3 is pushed from above, the rubber switch 3 The cap 3 is elastically deformed, the conductive electrode 5 contacts the two adjacent contacts 1a, 1a of the comb-shaped electrode 1, and the two contacts 1a, 1a.
Is conducted and the switch is turned on. The membrane switch 10 is designed to perform a switching operation by such an action.

The membrane switch 10 of this embodiment is constructed such that the upper surface of the protruding portion 3c surrounding the dome portion 3a of the rubber cap 3 is adhered to the lower surface of the fixing sheet 9, so that the conventional structure shown in FIG. As compared with the case where the rubber cap is bonded to the membrane sheet only on the lower surface of the dome portion like the membrane switch, the bonding area becomes larger, and as shown in FIG. Since it is sandwiched between the seat 2 and
The rubber cap 3 can be reliably fixed to the membrane sheet 2.

The fixed sheet 9 is the membrane sheet 2
Since it is configured to cover the upper surface of the
Not only has the effect of protecting the membrane sheet 2, but also has a so-called waterproof effect of preventing moisture from entering the electrode portions inside the rubber cap 3.

In this membrane switch 10, since the single rubber cap 3 is used as the rubber cap, unlike the case of the conventional integrated rubber cap 7 as shown in FIG. 5, an expensive resin used for the rubber cap is used. The material is small, and the material cost can be reduced.

The detailed structure such as the shape of the protruding portion 3c of the rubber cap 3 in the membrane switch 10 is not limited to this embodiment, and various design changes can be made.

[0023]

As described above in detail, in the membrane switch with the rubber cap of the present invention, since the protruding portion of the rubber cap is sandwiched between the fixed sheet and the membrane sheet, as in the conventional case, Compared to the structure in which the lower surface of the rubber cap is fixed to the membrane sheet only, the rubber cap can be reliably fixed to the membrane sheet, and as a result, reliability can be improved.

Further, since a single rubber cap can be used as the rubber cap, unlike the case of the conventional integrated type rubber cap, the expensive resin material used for the rubber cap can be reduced and the model of the electronic device can be used. Therefore, it is not necessary to manufacture a mold for manufacturing the rubber cap, so that the manufacturing cost of the membrane switch can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing components in an embodiment of a membrane switch with a rubber cap of the present invention.

FIG. 2 is a vertical sectional view showing a state in which the constituent elements of the embodiment are assembled.

FIG. 3 is a perspective view showing a rubber cap and a fixing sheet of the embodiment.

FIG. 4 is a vertical cross-sectional view showing a conventional membrane switch using a single rubber cap.

FIG. 5 is a vertical cross-sectional view showing a membrane switch using a conventional integrated rubber cap.

[Explanation of symbols]

1 ... Comb-shaped electrode (second electrode), 2 ... Membrane sheet,
3 ... Rubber cap, 3a ... Dome part (rubber cap body), 3c ... Projection part, 5 ... Conductive electrode (first electrode),
9 ... Fixed sheet, 9a ... Opening part, 10 ... Membrane switch

Claims (1)

[Claims] 1. A rubber cap, which is formed in a dome shape and has a first electrode provided on an inner surface thereof, is provided above the membrane sheet having a second electrode provided on an upper surface thereof. In the membrane switch with a rubber cap fixed so as to face each other, the rubber cap (3) projects outward from a dome-shaped rubber cap body (3a) and a lower end portion of the rubber cap body (3a). And a fixed sheet (9) fixed on the membrane sheet (2), and the fixed sheet (9) has an opening (9a). The rubber cap (3) is arranged such that the rubber cap body (3a) is projected upward from the opening (9a), and the projection (3c) is fixed. Sandwiched between the constant sheet (9) and the membrane sheet (2),
Membrane switch with a rubber cap that is fixed.