OPTICAL SHAPE MEASURING APPARATUS

摘要

PURPOSE:To measure the shape of the surface of an object in a contactless manner by creating an interference fringe from a reflected light from the object to be measured and a reflected light from a double-side mirror. CONSTITUTION:Light from a light source 1 irradiates the surface 30 of an object 3 to be measured and a double-side mirror 4. Lights reflected on these reflective surfaces are reflected with or transmit a half mirror 2 and then, form on interference fringe on image sensors 51 and 52 by interference with each other according to the same theory as in the interference by the Mickelson's optical system. An m-order high harmonic outputted from the image sensors 51 and 52 is heterodyne detected with mixers 61 and 62 and counted 81 and 82 separately through low-pass filters 71 and 72 to compute 9 the Z-direction displacement Z of an object 3 to be measured and the angle DELTApsi of inclination of the surface thereof.