Patent ID: 8014679

Claim:
An optical space transmission device comprising: a first portion; and a second portion which is rotatably connected to the first portion and performs space transmission of signals using light between the first portion and the second portion, wherein the device comprises: a first light emitting and receiving module which is provided for the first portion and includes: a first light emitting element composed of a light emitting diode emitting first signal light modulated based on a signal transmitted from the first to second portion; and a first light receiving element receiving second signal light modulated based on a signal transmitted from the second to first portions; and a second light emitting and receiving module which is provided for the second portion and includes: a second light emitting element composed of a semiconductor laser emitting the second signal light; and a second light receiving element receiving the first signal light; wherein an optical axis of the second signal light coincides with a central axis of rotation of the second portion relative to the first portion; and the second portion rotates around the optical axis of the second signal light.