Patent ID: 8124926

Claim:
A key device comprising: m number of first light-emitting portions that emit light propagating in a first direction (m is an integer of at least 1); n number of second light-emitting portions that emit light propagating in a second direction other than the first direction (n is an integer of at least 2); a plurality of converters, which are respectively provided at intersections of the light propagating in the first direction and the light propagating in the second direction and, in a case in which the m number of the first light-emitting portions and the n number of the second light-emitting portions emit the light at the same time, can convert the propagating direction of the light from the first direction to the second direction or from the second direction to the first direction; at least m number of first light-receiving portions that receive light propagating in the first direction through the converters; at least n number of second light-receiving portions that receive light propagating in the second direction through the converters; and a plurality of keys, which are provided correspondingly and to the plurality of converters, respectively, and which determine whether the propagating direction of the light in the converters is converted.