| 摘要 |
PURPOSE:To obtain a measured value which fluctuates less and and has high accuracy of the laser beam device having a function to measure a laser output by utilizing the light transmitted through a reflection mirror. CONSTITUTION:The front side boundary face 10a provided with a light reflection film 12 of the reflection mirror 10 faces an output mirror in nearly parallel therewith and the rear boundary face 10b is constituted to a tapered surface inclining by theta(for example, 1 deg.) with the front side boundary face 10a and diagonally faces the photodetecting surface of a photoelectric conversion element 102. A part (LB2) of the laser beam LB1 entering the inside of the reflection mirror 10 from a YAG rod 202 side passes IG the rear boundary face 10b of the reflection mirror 10 along the laser beam axis and is made incident on the photodetecting surface of the rear photoelectric conversion element 102. The laser beam LB4 emitted from the rear boundary face 10b of the reflection mirror 10 to the outside by repeating the internal reflection within the reflection mirror 10 advances in a diagonal direction at the angle largely inclining with the axis of the laser beam and is not made incident on the photodetecting surface of the photoelectric conversion element 102 on the axis of the laser beam. |
