JPS649306A - Detector for light transmitting fine pattern - Google Patents

Abstract

PURPOSE:To detect 3-D shape in a short time, by a method wherein a polarization filter with a polarization plane thereof made rotatable is arranged and when the polarization plane is in a first direction, an image of an object to be detected is compared with that separately detected when it is in a second direction different therefrom. CONSTITUTION:A polarization filter 2 with the polarization plane made rotatable (up to 90 deg.) is arranged between a laser beam source 1 and a lighting objective lens 4. Then, an image I1 (Fig. b) of an object 9 to be detected as detected when the polarization plane of the filter 2 is in the direction as indicated by the Fig. (a) and an image I2 (Fig. d) of the object 9 being detected as detected when that of the filter 2 is in the direction as indicated by Fig. (c) are obtained separately. Then, the images I1 and I2 thus detected are compared and processed by a detection means 6 to obtain an image I3 (Fig. e). That is, a line light R2 reflected on the surface of a light transmitting pattern 92 of the object 9 is reflected on the bottom surface of the pattern 92 while being discriminated from a line light R1 refracted on the surface of the pattern 92 thereby detecting a fine light transmitting pattern.