Patent ID: 8633433

Claim:
An optical potentiometer comprising: a linear power transmission member configured to move in a longitudinal direction; a retaining member configured to retain the linear power transmission member so as to be movable in the longitudinal direction; an optical element, an optical property of the optical element continuously varying along a moving direction of the linear power transmission member; a light source configured to emit light; a light receiving section configured to convert an optical property of input light into an electric signal; a linear light transmitting member configured to guide the light emitted from the light source and output the light to the optical element, and guide light input from the optical element to the light receiving section, an output position of the light emitted from the light source and an input position of the light input from the optical element being retained at certain distances with respect to the optical element; and a calculating section configured to calculate an amount of displacement between the linear power transmission member and the retaining member in the moving direction of the linear power transmission member based on the electric signal output by the light receiving section.