Optical displacement measuring system using a triangulation including a processing of position signals in a time sharing manner

摘要

An optical displacement measuring system using a triangulation comprises a light projecting unit for emitting to an object a light beam which is amplitude-modulated by a reference signal having a predetermined period, a light receiving unit for receiving light reflected back from the object and providing a pair of position signals, and a control signal generator for providing first and second control signals in synchronism with the reference signal. The position signals are processed by a switching unit in a time sharing manner according to the first control signal to obtain a first composite signal, in which the position signals occur alternately every integral number of the period of the reference signal. The first composite signal is amplified by a single amplifier at a desired amplification rate, and then sent to a distance determining unit, in which the polarity of the first composite signal is periodically reversed according to the second control signal to obtain a second composite signal, and a distance signal indicative of a distance between the light projecting unit and the object is determined from the second composite signal.