US Patent 7103074 Laser video projection system and method with anti-piracy feature

A pulsed laser device and a laser display system using the pulsed laser device are disclosed that thwart recording of displayed video images with electronic imaging devices. The pulsed laser device is Q-switched, whereby the Q-switch trigger pulses have a temporal pattern that includes a blanking period of a duration that is longer than a repetition time between consecutive trigger pulses and shorter than a time period perceived by the human eye. The output beam of the Q-switched pulse laser is frequency-converted by non-linear optical frequency conversion into an imaging beam, for example, a three-color RBG beam, that can be modulated for displaying color images. The blanking period renders the displayed images practically unsuitable for off-screen recording with electronic image recording devices, such as CCD movie cameras.