SURFACE INCLINATION MEASURING INSTRUMENT FOR OPTICAL DEFLECTOR

摘要

PURPOSE:To realize high accuracy and size reduction by calculating the difference between the outputs of two beam position detectors and finding the quantity of surface inclination. CONSTITUTION:The laser beam L1 emitted by a light source 1 is split by a polarization beam splitter(BS) 2 into a horizontal and a vertical component. The vertical polarized laser beam L2 is made incident on the BS 4 as a beam L2a through the optical deflector 3. Further, the horizontal polarized laser light L3 is made incident on the BS 4 as a beam L3a through a mirror M1. Then the composite light L4 projected from the BS 4 is made incident on a BS 5 through mirrors M2 and M3. Then the vertical polarized light L5A transmitted through the BS 5 is made incident on a sensor 6 and the horizontal polarized light L5b which is reflected by the BS 5 is made incident on a sensor 7. Then the sensors 6 and 7 detects the positions of the laser beams and output electric signals A and B. Further, the signals A and B are inputted to a differential output circuit C and the difference between the signals A and B is outputted as a final surface inclination signal.