METHOD FOR NONCONTACT MEASUREMENT OF SURFACE SHAPE AND DEVICE THEREOF

摘要

Even if return light (L') from a work to be measured (1) does not match with the center of a two-section sensor (S), when a voltage difference between the two sensors (a, b) of the two-section sensor (S) falls within a vicinal range, the amount of movement of an objective lens means (4) until the objective lens means (4) is focused (until the return light (L') coincides with the center of the two-section sensor) can be computed by computing a correction value from the voltage difference and adding the correction value to the actual vertical position of the objective lens (4).