Optical angle sensor using polarization techniques

摘要

A three-phase angular position sensor is described in which three beams of light having polarization directions rotated 60 DEG to each other are passed through a polarizer, the rotational position of the polarizer representing an angle to be measured. The intensities of the beams transmitted through the polarizer uniquely encode its angle over a 180 DEG range. This range may be doubled, for example, by including a binary track. A two-phase angular position sensor is also described in which two beams have polarization directions oriented 45 DEG with respect to one another.