| 摘要 |
PROBLEM TO BE SOLVED: To attain the easy and assured exchange of light emitting elements by making a 1st holder hold a light emitting element and a collimator lens in a signal body and making a 2nd hold removably the 1st holder to lead the transmitting light beam emitted from the collimator lens to a transmitting optical system. SOLUTION: A laser diode 20 is held in a single body with a collimator lens 21 by a holder 50 of an almost cylindrical shape. When the diode 20 is exchanged with another one, the diode 20 is exchanged together with the lens 21 via the holder 50. The holder 50 is guided along the inside wall surface of a cylindrical part 7A of a lens barrel main body 7 to be set at the body 7 and has a ring-shaped flange 50A at its outer circumference. The end face of the flange 50A positioned at the side of the body 7 forms a flat surface with high accuracy. The end face of the part 7A of the body 7 is machined with high accuracy to be set vertical to the optical axis of a receiving light beam L2 going toward a position detection element 24 and also to be a flat surface. |
