Importance

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Abstract

A keyboard switch having a membrane contact point sheet and a push button key for pressing down a contact point portion of the membrane contact point sheet, further includes a housing including a base portion and a casing portion, a key top which is slidably supported in the casting portion and has a contact point pressing portion projecting toward the base portion in an area extending outside a periphery of the casing portion, and a biasing member for biasing the key top toward a home position. The membrane contact point sheet is disposed on the base portion of the housing so that the contact point portion is confronted with the contact point pressing portion, and is formed in a three-layered structure, including an upper contact point sheet, a spacer, and a lower contact point sheet. The contact point portion has a window hole provided in the spacer. A first contact point is formed on a lower surface of the upper contact point sheet at a place corresponding to the window hole and a second contact point is formed on an upper surface of the lower contact point sheet also at a place corresponding to the window hole. The biasing member is a spring member disposed between the casing portion and the contact point pressing portion formed on the key top.

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First Claim