Layers of a thin, electrically insulating material are bonded together to form a switch. The bottom layer of the switch has electrically conductive areas aligned with openings through a second layer. A third layer has a pattern of spaced lines of an electrical conductor positioned over the openings in...http://www.google.com.tw/patents/US4931601?utm_source=gb-gplus-share專利 US4931601 - Pressure switch having internal vent chamber
