OPTICAL DISPLACEMENT MEASURING DEVICE AND METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a photoelectric displacement measuring device and method, capable of correcting the quantity of light of a light-emitting element in a short time. SOLUTION: An object to be measured B is irradiated with a beam light, obtained by transmitting the radiant light of the light-emitting element 1 through a light- projecting lens 2. By condensing a part of diffuse reflected light reflected at the object to be measured B by a light-receiving lens 3, the light-receiving plane of a CCD element 4 is irradiated with a spot light. A plurality of light-receiving cells are arranged with a regular pitch in the light-receiving plane of the CCD element 4. A displacement detecting part 5a detects the center location of the spot light from the output of each light-receiving cell and obtains the displacement of the object to be measured from the displacement of the center location. When the output of one of the light- receiving cells is saturated, a peak value estimating part 5b estimates the output peak value from the output waveform obtained by arranging the output of each light- receiving cell in the order of arrangement. A light quantity control part 5c controls the quantity of light of the light-emitting element 1, so that the estimated peak value lies within the output range of the light-receiving cells.