| 摘要 |
PURPOSE:To facilitate position setting by dividing the beam from a laser head to a transmitted beam and a reflected beam by a beam splitter and projecting the former to a reference reflection mirror and projecting the latter to a measurment-side reflection mirror. CONSTITUTION:A projecting part 13' is formed in the position, which faces a window 11, on the rear-side face of a box body 13 which have the first and the second windows 11 and 12 on side faces forming 90, and a reference reflection mirror 14 is provided in this part 13', and a beam splitter 15 is installed in the box body 13, thus constituting an interferometer 10 arranged between a laser head 1 and a measurement-side reflection mirror 16. The reflection mirror 16 is provided in the position facing the window 12, and a beam A from the head 1 is divided to a transmitted beam A2 and a reflected beam A1 by the splitter 15, and beams A2 and A1 are projected to mirrors 14 and 16 respectively. Thus, length measurement is started after only positioning due to the interferometer 10 and the mirror 16. |
