Photoelectric microscope

A method of positioning a test piece having a reference line thereon, comprising the steps of forming a magnified real image of the reference line of said test piece and a point-symmetric image thereof on an identical focal plane by means of an objective and an optical system for making point-symmetric images as disposed in an optical path of said objective, passing the lights of the respective images through two openings provided in a slit plate for scanning said focal plane, introducing the lights passing through the slit plate into two photoelectric transducers disposed behind said respective openings, to convert them into electric signals, detecting the amount of deviation of said test piece from a central optic axis as determined by said objective and said optical system for making point-symmetric images from the relation of the time difference between the generation of said two electric signals.

A method of positioning a test piece having a reference line thereon, comprising the steps of forming optical images of said reference line on said test piece as first and second images point-symmetric to each other on an identical focal plane, scanning said images on said focal plane, converting the brightnesses of the respective optical images into electric signals by photoelectric elements and detecting the relative positions between said reference line and an optic axis of said objective as well as the point-symmetry optical system from a distance by which the respective photoelectric elements actually scan while output signals are obtained from said respective photoelectric elements.