DEVICE FOR MEASURING PARALLELISM OF TRANSPARENT BODY

PURPOSE:To enable measurement with high accuracy even if a dark room is not utilized by matching the laser beam from a laser oscillator and the normal of the 1st surface of a transparent body and calculating parallelism from the output of a two-dimensional detecting element which detects the laser beam transmitted through the transparent body. CONSTITUTION:A means for detecting surface mating is constituted of a beam splitter 2 which bisects the beam from a laser oscillator 1, a mirror 3, a beam expanding lens 4 and a screen 5. A sample 6 is placed on a stage 7 of which the axial rotation perpendicular to the beam, the inclination to the axis as well as the swing and tilt and respectively adjustable. The beam from the oscillator 1 and the beam reflected from the 1st surface of the sample 6 are matched. A two-dimensional detector 8 is placed in the prescribed position from the sample 6 and the beam position in the state in which there is no sample 6 is detected by the detector 8. The inclination of the 1st and 2nd surfaces of the sample 6 and the direction thereof are calculated by an arithmetic device 9 from the deviation in the beam position in the state in which the sample 6 is placed. The result thereof is displayed on a display device 10.