Measuring arrangement for use in e.g. yaw rate sensor for optically measuring speed of drive shaft of asynchronous motor, has retroreflector for rotating polarization of incident light around preset value with increased reflection

摘要

The arrangement has a polarizing filter reflected light barrier (1) for emitting linearly polarized light (2) and receiving light with polarization direction rotated around 90 degrees to the emitted light. A retroreflector (5) is supported at a front side (3) of a shaft (4) and rotates polarization of incident light around 90 degrees to a preferred direction with increased reflection, where the retroreflector is formed as a micro prismatic reflex foil. An electrically controllable component i.e. liquid crystal light modulator, influences the polarization direction of the received light.