| 摘要 |
In a membrane switch which is constituted of a lower membrane sheet, an upper membrane sheet and a spacer sheet which is inserted between both sheets, a spring sheet which is formed of a thin metal plate is arranged over the upper membrane sheet and, at the same time, a pair of slits are formed in the spring sheet at positions corresponding to both sides of an upper electrode of the upper membrane sheet. Further, the membrane switch is arranged below a holder member. When a key top 21 is pushed down, a switch portion of the spring sheet is pushed down by a pushdown projection of the membrane switch. Further, in another membrane switch which is constituted of a lower membrane sheet, an upper membrane sheet and a spacer sheet which is inserted between both sheets, a spring sheet which is formed of a thin metal plate is arranged over the upper membrane sheet and, at the same time, a semispherical bulging portion is formed on the spring sheet corresponding to an upper electrode. Further, the upper membrane sheet is configured to be pushed by a connecting portion between the bulging portion and the spring sheet. Further, in such a key switch, the membrane switch is arranged below a holder member and the bulging portion is pushed down by a pushdown projection of the holder member at the time of pushing down the key top 21.
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