AN ANGLE-OF-ROTATION SENSOR USING FLIP-FLOP PHOTODETECTING TECHNIQUES

A simple, effective and compact method for detecting angle of rotation has been developed. This has been achieved by incorporating flip-flop photosensing techniques. A single sensing element yields a one or zero output, which when connected, in a one-dimensional array can be used to give a pattern corresponding to the position of the light beam. In order to avoid the need for a synchronized clock, latch circuitry has been included, which yields a clock-independent output from each sensing cell. Further latch circuitry is used to give hysteresis of the switching levels. This reduces the parasistic effects of mechanical vibration or light fluctuations. Additional signal processing has been developed that yields two outputs, giving the rate and direction of rotation. © 1990.