Patent ID: 8807766

Claim:
A laser scanning projection apparatus with phase detection and compensation, the laser scanning projection apparatus comprising: an illumination unit for emitting a laser beam; a projection surface; a scanning mirror for reflecting the laser beam, so that the laser beam is periodically swept across the projection surface and a plurality of image frames are sequentially generated at a specified image refresh rate; a projection window comprising a transmissible part and a blocking part around the transmissible part, wherein a reflection-differential pattern is formed on a surface of the blocking part, wherein when the laser beam reflected by the scanning mirror is projected on the transmissible part, the laser beam is transmitted through the transmissible part and projected on the projection surface, wherein when the laser beam reflected by the scanning mirror is projected on the reflection-differential pattern of the blocking part, a reflective beam with different intensities is reflected by the reflection-differential pattern; an optical sensor for receiving the reflective beam, thereby generating a sensing signal indicative of an intensity level of the reflective beam; and a controlling unit for calculating a phase difference between an actual projection position and a predetermined projection position of the laser beam according to the sensing signal, and compensating a subsequent image frame according to the phase difference.