Patent ID: 7420997

Claim:
A method of controlling a laser projection system comprising a visible light source, wherein the visible light source comprises a semiconductor laser and the method comprises: generating at least a portion of a scanned laser image by configuring the semiconductor laser for optical emission of encoded image data and scanning an output beam of the visible light source across a plurality of image pixels or encoded data periods, at least one parameter of the optical emission being a function of a drive current I GAIN injected into a gain section of the semiconductor laser and one or more additional drive currents I/V PHASE , I/V DBR , the additional drive signal I/V PHASE being applied to a phase section of the semiconductor laser and the additional drive signal I/V DBR being applied to a wavelength selective section of the semiconductor laser; altering mode selection in the semiconductor laser as the output beam is scanned across the image pixels or encoded data periods by perturbing at least one of the additional drive currents I/V PHASE , I/V DBR with a perturbation signal I/V PTRB , the perturbation signal I/V PTRB comprising an amplitude profile that varies significantly enough over time to alter mode selection in the semiconductor laser such that a plurality of different emission modes are selected in the semiconductor laser as the output beam is scanned across the image pixels or encoded data periods.