Scanner phase control for a scrolling color projector

摘要

A scanner phase control for a scrolling color projector utilizes the back-EMF value of a motor which rotates a prism of the scanner to set a reference point for the prism. A reference phase signal is provided which corresponds to timing information of the scan of a stripe of light provided by the prism. The phase of the motor is altered in response to the reference phase signal such that the back-EMF zero crossings of the motor coincide with the beginning of a scan as identified by the reference phase signal.