AUTO-FOCUSING METHOD AND PROJECTOR USING THE SAME

摘要

A projector for automatically adjusting images projected onto a screen comprises a detecting module for detecting the propagation time for the emitted ultrasonic wave sent by the projector to be echoed back by the screen as the reflected ultrasonic wave and received by the projector, a processing module for calculating a distance between the projector and the screen based on the propagation time, and outputting control signals, and an adjusting module for adjusting optical parameters of an optical module according to the control signals.