Patent ID: 6774881
Filing Date: 2004-08-10
Classification: G02F,H04N

Abstract:
An R,G,B laser light source with reduced speckle noise adapted for use with a display system, which light source generates R, G and B beams and comprises:a laser with a laser medium producing a laser output beam with a plurality of output beam wavelengths; an R-channel receiving a first portion of the output beam at a first output beam wavelength and generating the R beam, with the R-channel including a resonant cavity with a first nonlinear crystal producing optical radiation having a first wavelength that is greater than the first output beam wavelength and a spectral width that is greater than a spectral width of the first output beam wavelength, and a second nonlinear crystal that combines the radiation of the first wavelength with the first portion of the output beam to generate the R beam by sum frequency mixing, said R-beam having a spectral width determined by the spectral width of the optical radiation of the first wavelength; a G-channel receiving a second portion of the output beam at the first output beam wavelength and generating the G beam, with the G-channel including a resonant cavity with a third nonlinear crystal producing second harmonic optical radiation of the first output beam wavelength, with the cavity of the G-channel further including an etalon that produces a plurality of longitudinal G-channel resonant cavity modes which define a spectral width of the G-channel; and a B-channel receiving a portion of the output beam at a second output beam wavelength; a first harmonic crystal producing a frequency-doubled wavelength of the second output beam wavelength; and a fourth nonlinear crystal that combines the laser output beam at the second output beam wavelength with the frequency-doubled wavelength of the second output beam wavelength to produce the B beam; with the spectral width of the R-channel and the G-channel reducing the speckle noise of the R,G,B laser light source.