A keyboard unit comprises a keyboard base and a number of key-tops. A switch in the form of a sheet is interposed between the keyboard base and the key-tops. The switch has a number of movable contacts arranged corresponding to the key-tops, and a number of stationary contacts opposed to the respective...http://www.google.de/patents/US6590565?utm_source=gb-gplus-sharePatent US6590565 - Keyboard unit having pop-up key-tops and electronic apparatus incorporating the keyboard unit
