Abstract:
A self-balancing optical position sensitive detector includes a pair of spaced apart, parallel, longitudinally extending doped regions on a first surface on a front side of a substrate 16 of opposite doping type with contact pads on the front side at respective ends of a first doped region of the pair. A voltage source applies a potential difference between the contact pads of the first doped region. On the front side, a contact pad of the second doped region of the pair provides an analog output signal representative of a longitudinal position of a center of gravity of an incident light pattern along the doped regions without external circuitry processing the output signal to obtain a readout of the longitudinal position. A resistive line may directly overly, abut and be in contact with at least a portion of the first doped region. A conductive line may directly overly, abut and be in contact with at least a portion of the second doped region. No backside contact or processing of the substrate is required or employed.
Abstract:
A potentiometer includes a shaft, a base including a printed circuit board on which are fixedly mounted a light emitter and a light receiver arranged opposite to and spaced from the light emitter, the light emitter being supplied with steady voltage to emit light and provide working voltage to the light receiver, a circular seat formed with an opening and fixedly mounted on an upper end of the shaft, a plastic film arranged on an outer edge of the opening and disposed between the light emitter and the light receiver, the plastic film being provided two end portions which are opaque and an intermediate portion which decreases in transparency from one side to another side thereof, and a cover fixedly mounted on the base to enclose the circular seat, whereby the potentiometer is of high sensitivity, durable in use, low in cost, easily converted from a conventional rheostat and fit for mass production.