Patent ID: 8274478

Claim:
A multi-directional keypad switch, comprising a keypad housing with a top surface; a lower mount surface; an emitter and detector disposed on said lower mount surface, said emitter and detector configured to permit said emitter to emit a light beam towards said detector; and a key with a top surface exposed to operate said key, said key being slidable in a lateral direction parallel to said top surface, said key having a bottom surface with a slot perpendicular to said top surface; wherein said slot in said bottom surface of said key is positioned to straddle said light beam emitted by said emitter, wherein sides of said slot in said bottom surface are perpendicular to said lower mount surface, said sides of said slot in said bottom surface attenuate substantially half of said light beam when said key is in a central position; wherein when said key is moved in a lateral direction from said central position that is substantially ninety degrees to said light beam, said light beam is laterally attenuated by said sides of said slot in said bottom surface of said key in an amount greater than substantially half of said light beam; wherein said detector detects an amount of lateral attenuation of said light beam and based on said amount of lateral attenuation said detector determines a lateral position of said key in said light beam, said emitter and detector being configured for detecting a plurality of different amounts of lateral attenuation varying form a first amount where substantially half of said light beam is attenuated to a second amount where greater than substantially half of said light beam is attenuated and can detect at least one lateral position of said key stem based on an amount of lateral attenuation that is between said first amount and said second amount.