| 摘要 |
PROBLEM TO BE SOLVED: To make an optical signal transmission device small in size, small in diameter and low in cost while supplying a stable quantity of received light to a light receiving element in two-way communication using an optical signal.SOLUTION: A rotary joint 10 comprises: a fixed part 20 and a rotary part 30 which are arranged substantially orthogonally to a center axis X and opposite to each other; and a substantially columnar light guide member 40 disposed therebetween. The fixed part 20 is provided with a light emitting element 22 and a light receiving element 24, and the rotary part 30 is provided with a light receiving element 34 receiving light emitted from the light emitting element 22 and a light emitting element 32 emitting light toward the light receiving element 24. There is an intersection C of the fixed part 20 and the center axis X at a substantially center part of a straight line LA connecting the light emitting element 22 and the light receiving element 24 together, and there is an intersection C' with the rotary part 30 at a substantially center part of a straight line LB connecting the light emitting element 32 and the light receiving element 34 together. Light beams emitted by the light emitting elements 22 and 32 are reflected in the waveguide member 40 to supply stable amounts of light to the light receiving elements 24 and 34.SELECTED DRAWING: Figure 1 |
