Abstract: Fluorescent optical switch and keyboard apparatus wherein a plurality of fluorescent optical key switches are arranged in a matrix array of rows and columns with a key disposed at each column-row intersection and wherein each key carries a fluorescent optically reflective element thereon. A single optical photo-diode disposed at each key location is caused to operate in three discrete modes with respect to the fluorescent element. In one mode the diode emits light which is caused to be reflected upon key when the key is depressed. In another mode the reflected light striking the diode causes the diode to act as a photo-receptor effectively indicating key actuation.

Abstract: A multi-plane optical membrane switch for use for example in a keyboard matrix is formed by two flat, planar, clear, plastic members disposed in parallel, separated relationship and each having individual light conducting guides or channels thereon. The channels of the lower plane are disposed at right angles to the channels of the upper plane. The upper set of light guides includes integral, gently curving coupler taps disposed at the intersection of the upper and lower guides for coupling the light from the lower planar guide channels into the upper guide channels when the two channel intersections are pressed together by the key top effectively switching the light from the lower to the upper channels.