Patent attributes
An optical switch keyboard includes a circuit module and plural keys. The circuit module includes a circuit board, plural light emitters, plural light receivers and plural light sources. Each key corresponds to a light emitter, a light receiver and a light source. The plural light emitters and the plural light receivers are disposed under the circuit board. Consequently, the plural light emitters and the plural light receivers are not interfered by the ambient light that comes from the top side of the circuit board. In case that the light sources are disposed over the circuit board, the light beams from the light sources are transmitted upwardly through light-transmissible triggering elements of the corresponding keys and projected to the keycaps. Consequently, a visual effect is generated.