Patent ID: 7906915

Claim:
A pushbutton switch mechanism comprising: an array of light emitting diodes; and a plurality of driver circuits, each driver circuit driving three pairs of the light emitting diodes, each driver circuit including switching diodes and switching resistances collectively switching the three pairs of light emitting diodes between series connection as six light emitting diode connected in series with each other between first and second nodes and parallel connection as three pairs of series-connected light emitting diodes connected in parallel with each other between the first and second nodes and with each pair of series-connected light-emitting diodes connected in parallel with one of the switching resistances, each driver circuit switching the three pairs of light emitting diodes between series connection and parallel connection as an input voltage applied to the respective driver circuit is varied between a value equaling or exceeding cumulative forward bias voltage of the three pairs of light emitting diodes and the switching diodes and a value less than the cumulative forward bias voltage.