US Patent 7526155 Rotary joint

A rotary joint 1 capable of stably transmitting superfine images and high-speed data is provided. The rotary joint 1 includes a stationary part 3 and a rotary part 2 rotatable about an axis against the stationary part 3 and transmits light signals between the stationary part 3 and the rotary part 2. The rotary part 2 includes at least one light transmissive cylindrical member 101 arranged coaxially with the axis, a light emitting element 11 and a light receiving element 14 both arranged on one end of the member 101. While, the stationary part 3 includes a light receiving element 12 opposed to the light emitting element 11 in the rotary part 2 and a light emitting element 13 opposed to the light receiving element 14 in the rotary part 2.