LASER BEAM PATH LENGTH VARYING APPARATUS

摘要

PURPOSE:To obtain the desired optical path by changing the number of paths without change of the incident path and the emitting path in the multi-path optical system. CONSTITUTION:A laser beam path length varying apparatus 10 is provided with a multi-path optical system consisting of a concave reflection mirrors 104 and 106 with the concave reflection mirror 106 provided rotatable around the center axis O. A reflection mirror 12 is provided on the optical path of the laser beam D which is emitted from a through hole 106a of the concave reflection mirror 106 and the laser beam D emitted from the through hole 106a is reflected toward a reflection mirror 14 arranged on the center axis O. The reflection mirror 14 reflects the laser beam D incident from the reflection mirror 12 along the center axis O. These reflection mirrors 12 and 14 are rotated synchronously with rotation of the concave reflection mirror 106.