Scanned Optical Keyboard
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20
A low-cost optical keyboard with selectively illuminable keys is illustrated. In general, optical keyboards require multiple light sources and detectors for sensing key depressions at intersections in a matrix array. Typical embodiments utilize one light source per row and one detector on each row and column or some combination of these arrangements. Such arrangements are usually expensive and are potentially unreliable due to the probability of failure of any one component. The present disclosure utilizes a single light-emitting diode (LED) per key location. The LED is used to illuminate the key as an indicator as well.