Variable light transmission filter and optical analog position sensor

摘要

A light transmission filter for transmitting a beam of light of any wave length. The filter is made up of a pattern of opaque figures positioned along a transparent substrate. The spacing between figures is varied along the substrate so that the beam of light intercepted by the filter is variably transmitted as a selected function of the longitudinal position of the filter relative to the beam of light. The spacing of the figures along the substrate is selected to achieve a light transmission characteristic for the film in accordance with a desired mathematical function. An optical analog position sensor for sensing the position of a movable member along a prescribed path including the optical transmission filter attached to the movable member with the substrate having a longitudinal configuration corresponding to the prescribed path. The intensity of a fixed beam of light transmitted through the filter indicates the position of the member.