IMPROVED MEMBRANE KEYBOARD

摘要

A membrane keypad is disclosed having a "collapse action" operation to provide tactile feedback. The keypad has a rigid substrate (5) with a number of depressions therein associated with each pad region. A cup-shaped flexible membrane portion (11) is positioned within each depression and extends between the base of the depression and a flexible upper membrane layer (3). The upper layer is provided with a pair of contacts (4) which in operation are connected by a conductive rubber bridging contact (13) provided on the base of said cup-shaped portion. A second flexible membrane portion (8) extends from the edge of said cup-shaped portion to the wall (6) of said depression. In operation the flexible upper membrane (3) is depressed forcing the second portion (8) to cantilever about the wall of the depression while also compressing the wall of the cup-shaped portion (11). When the second portion (8) is forced into the base of the depression the base of the cup-shape portion is raised upwards to contact the downward moving flexible membrane. The walls (6) define round, rectangular or channel shaped depressions.