Polymatech Co., Ltd.

Toshikazu Yoshioka

Masaya Katori

Tedi Kunthady

Akira Senzui

Disclosed is a key sheet helping to solve problems caused by a rubber-like elastic material filling dividing grooves. A key sheet is provided with protrusions swelling from the back surface of an operation plate toward dividing grooves. The protrusions, which are formed by a film sheet formed of a thermoplastic resin, can prevent the problems when the rubber-like elastic material filling the dividing grooves are exposed, that is, separation or severance of the rubber-like elastic material. Further, nails or fingertips are not easily allowed to enter the dividing grooves of the operation plate. The protrusions in the grooves formed by the film sheet are not easily worn out through repeated depressing operation, thus realizing a thin and safe key sheet.

Key sheet

Provided is a key sheet in which fixation members such as key tops can be firmly fixed to a base sheet. The back surfaces of the key tops are fixed to a film sheet without involving any gaps by means of adhesion layersstacked on the entire back surfaces of the key tops. Thus, fingernails or the like are not easily allowed to get between the key tops and the film sheet, making it possible to prevent the key tops from being unstuck from the film sheet. Further, in the key sheet, the film sheet and a base sheet are integrated with each other, so the key tops can be firmly fixed to the base sheet through an intermediation of the film sheet, making it possible to prevent the key tops from being detached by fingernails or the like at the time of depressing operation.

Key sheet and pushbutton switch

Disclosed is a thin key sheet that is relatively free from breakage due to depressing operation. When key tops are depressed, float-supporting portions of rubber moldings and a film sheet undergo deformation, and a depression load can be borne by both the float-supporting portions and the film sheet, so the load on the float-supporting portions is mitigated, making the float-supporting portions less subject to breakage. Further, since the film sheet exists between the rubber moldings and a resin plate, it is possible to prevent the rubber moldings from being rubbed against a side wall of a frame portion, making it possible to prevent breakage due to rubbing between the rubber moldings and the resin plate.

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Tokyo, Japan

Toshikazu Yoshioka