JPH0446335Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a so-called membrane switch, which is a switch device formed by laminating insulating sheets on which conductive patterns are formed with a spacer sheet interposed therebetween.

[Background of the idea]

3 and 4 show conventional examples of this type of switch device, with FIG. 3 being a sectional view of the main part, and FIG. 4 being a plan view with the upper insulating sheet removed.

In these figures, an upper insulating sheet 1 and a lower insulating sheet 2 made of flexible resin each have lead extraction portions 1 protruding at corresponding positions.
a, 2a, and a spacer sheet 3 is interposed between both sheets 1, 2 except for the lead extraction portions 1a, 2a, and both sides of the spacer sheet 3 are covered with an upper insulating sheet, respectively. 1 and the lower insulating sheet 2. An upper electrode 4 and its lead 5 are provided on the lower surface of the upper insulating sheet 1.
However, the lower electrode 6 is also on the upper surface of the lower insulating sheet 2.
and its leads 7 are patterned, and these upper and lower electrodes 4 and 6 face each other through a through hole 8 formed at a predetermined position in the spacer sheet 3, and both electrodes 4 and 6 The leads 5 and 7 are led out to the outside through the lead extraction portions 1a and 2a, respectively. Furthermore, if the leads 5 and 7 formed on the lead extraction parts 1a and 2a are exposed, water droplets and the like will adhere to them and cause them to be shot.
Insulating coat tapes 9 and 10 are attached to cover the leads 5 and 7, respectively.

In the switch device having the above structure, when a pressing force is applied from above the upper insulating sheet 1 in the direction of the arrow in FIG. state. Moreover, when the pressing force is removed, the upper electrode 4 is separated from the lower electrode 6 due to the restoring force of the upper insulating sheet 1, and the upper electrode 4 is turned off.

By the way, this type of switch device is used, for example, as a keyboard switch for a microwave oven, so it is necessary to take precautions to prevent the occurrence of shortening of the conductive pattern due to intrusion of water vapor or dew condensation.
Thorough consideration is required. However, in the conventional switch device described above, a gap 11 or 12 through which outside air can enter is formed in the portion where the end of the insulating coated tape 9 or 10 and the end of the spacer sheet 3 overlap. There is a drawback that water droplets and the like adhere to the leads 5 and 7 facing the gaps 11 and 12 and are easily shot.

[Purpose of invention]

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
It is an object of the present invention to provide a switch device which prevents the occurrence of lead shortening due to the intrusion of water vapor or the like.

[Summary of the idea]

In order to achieve this object, the present invention provides a part of the spacer sheet with a protrusion extending along the lead extraction part, covers the leads on the lead extraction part with the protrusion, and thus is different from the conventional spacer sheet. The present invention is characterized by eliminating the need for insulating coated tape, which forms undesirable voids in the overlapping portions.

[Example of idea]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

Fig. 1 is a cross-sectional view of a main part showing an embodiment of the switch device of the present invention, and Fig. 2 is a plan view of the switch device with the upper insulating sheet removed, with reference numeral 3a in the figure.
is a protrusion of the spacer sheet, and the same reference numerals are given to the parts corresponding to those in FIGS. 3 and 4 described above.

In FIGS. 1 and 2, an upper insulating sheet 1 and a lower insulating sheet 2 are made of flexible resin such as polyester and have protruding lead extraction portions 1a and 2a at corresponding positions, respectively. A spacer sheet 3 having a protruding portion 3a is interposed between the upper and lower insulating sheets 1 and 2, and is adhered to almost the entire surface of both sheets 1 and 2 including the lead extraction portions 1a and 2a. That is, the protruding portion 3a of the spacer sheet 3 extends along the lead extracting portions 1a and 2a, and both surfaces of the protruding portion 3a are adhered to the lead extracting portions 1a and 2a, respectively. On the other hand, the upper electrode 4 and its lead 5 are patterned on the lower surface of the upper insulating sheet 1, and the lower electrode 6 and its lead 7 are patterned on the upper surface of the lower insulating sheet 2 by silver printing and then carbon printing. There is. These upper and lower electrodes 4 and 6 are connected to the spacer sheet 3
The leads 5 and 7 of both electrodes 4 and 6 are connected to the lead extraction parts 1a and 2a, respectively.
It is extracted to the outside through the process. Here, the leads 5 and 7 formed on the lead extraction parts 1a and 2a are
is covered with the protruding portion 3a of the spacer sheet 3, and there is no risk of water droplets or the like adhering thereto.

In other words, the switch device having the above configuration,
The protruding portion 3a of the spacer sheet 3 plays the role of the insulating coated tape conventionally used to cover the leads 5 or 7 on the lead extraction portion 1a or 2a, and such an insulating coated tape is no longer necessary. As a result, the undesirable void that was conventionally defined in the overlapped portion of the spacer sheet 3 and the insulating coated tape, that is, the lead 5 or 7
The gap that exposed the leads to the outside air is eliminated, and the occurrence of shortening of the leads 5 and 7 due to the intrusion of water vapor etc. is reliably prevented. Furthermore, since there is no need to attach an insulating coat tape, the assembly work is also simpler than before.

Note that the operation of the above embodiment is similar to that of the prior art example described above, so a description thereof will be omitted.

[Effect of idea]

As explained above, according to the present invention, the protrusions provided on the spacer sheet cover the leads on the lead extraction part, eliminating the need for insulation coated tape. Since the previously defined undesired voids are eliminated, the occurrence of shortening of the reeds due to the intrusion of water vapor and the like is reliably prevented. Moreover, there is also the advantage that the assembly work is simplified since the work of pasting the insulating coat tape is not necessary.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the essential parts of an embodiment of the switch device of the present invention, Fig. 2 is a plan view with the upper insulating sheet removed, and Fig. 3 is an example of a conventional switch device of this type. A sectional view of the main part, and FIG. 4 is a plan view with the upper insulating sheet removed. DESCRIPTION OF SYMBOLS 1...Upper insulating sheet, 1a...Lead extraction part, 2...Lower insulating sheet, 2a...Lead extraction part, 3...Spacer sheet, 3a...Protrusion part, 4
...Top electrode, 5...Lead, 6...Bottom electrode,
7...Lead, 8...Through hole.

Claims (1)

[Scope of utility model registration request] A spacer sheet is interposed between an upper insulating sheet provided with an upper electrode and a lower insulating sheet provided with a lower electrode, and the upper and lower electrodes face each other so as to be able to come into contact with each other through a hole in the spacer sheet. , in a switch device in which the leads of both electrodes are led out to the outside through a protruding lead extraction part of the upper or lower insulating sheet, a part of the spacer sheet is provided with a protrusion extending along the lead extraction part; A switch device characterized in that the protruding portion covers the lead on the lead extraction portion.