Abstract

An optical displacement measuring apparatus utilizing triangulation, includes a laser for projecting a laser light beam with a first optical axis onto a surface of an object whose displacement is to be measured; an array of photodetectors for receiving light reflected from the object and for generating a positional signal as an image displacement δ; a condensing lens for receiving the light reflected from the object and for supplying the reflected light to the detector array along a second optical axis intersecting the first optical axis at angle θ, the detector array being inclined at an angle $c; with respect to the second optical axis; a determining device for non-linearly determining surface displacement as a function of the image displacement δ and the angles $c; and θ, with the relationship between the image displacement δ, the surface displacement and the angles $c;and θ always being identical, regardless of the angle $c;.