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.

Disclosed in the present invention is a short-range optical potentiometer module, comprising a potential base body provided with a key slot, and a potential key which is mounted inside the key slot and can be displaced up and down, wherein a reset member for resetting the potential key is also arranged inside the key slot, an optical pair transistor composed of a photosensitive element and a light-emitting element is arranged inside the potential key, the optical pair transistor can be displaced up and down along with the potential key, a key base is internally provided with a fixed grating corresponding to the optical pair transistor, the reset member is sleeved on the grating, and the grating is configured such that the flux of light received by the photosensitive element from the light-emitting element changes along with the up-and-down displacement of the potential key, thereby causing an electrical signal generated by the photosensitive element to change along with the displacement of the potential key. The module of the solution uses non-contact photoelectric elements, thereby greatly increasing the service life; when the change in flux of light at the same distance is adjusted, the overall height of the module is close to or the same as the height of a potential base body; and the module has a skillful overall structure layout, can be conveniently assembled and replaced, and has strong practicality.