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US 6,304,237 B1Granted
Monochromatic R,G,B laser light source display system and method
AssigneeCorporation for Laser Optics Research
InventorMasayuki Karakawa
Life of this patent
Estimating the term…
Abstract
A monochromatic red (R), green (G), blue (B) pulsed laser light source (FIG. 2) for use in a full color video/image display system particularly an LCD display system (FIG. 3), the light source generating R,G,B laser beams with minimum speckle noise, and having digital color space conversion incorporated within.
Claims28
An R,G,B pulsed 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 pulsed laser output beam of selected pulse width and wavelength;
- an R-channel receiving a first portion of the output beam 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 wavelength of the output beam and a spectral width that is greater than a spectral width of the output beam, 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 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 output beam, 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 third portion of the output beam and generating the B beam, with the B-channel including a fourth nonlinear crystal that frequency-doubles the third portion of the output beam, and a lasing cavity having a Ti:S laser crystal pumped with the frequency-doubled output beam and producing a lasing wavelength that is twice the wavelength of the B-beam, said lasing wavelength being frequency-doubled by a fifth nonlinear crystal located in the lasing cavity and producing the B-beam;
- with the spectral width of the R-channel and the G-channel reducing the speckle noise of the R,G,B pulsed laser light source.
3 more elements
A color image video display system comprising:
- an R,G,B pulsed laser light source with reduced speckle noise, which light source generates R, G and B beams and includes
- a laser with a laser medium producing a pulsed laser output beam of selected pulse width and wavelength;
- an R-channel receiving a first portion of the output beam 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 wavelength of the output beam and a spectral width that is greater than a spectral width of the output beam, 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 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 output beam, 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 third portion of the output beam and generating the B beam, with the B-channel including a fourth nonlinear crystal that frequency-doubles the third portion of the output beam, and a lasing cavity having a Ti:S laser crystal pumped with the frequency-doubled output beam and producing a lasing wavelength that is twice the wavelength of the B-beam, said lasing wavelength being frequency-doubled by a fifth nonlinear crystal located in the lasing cavity and producing the B-beam.
3 more elements
A method of producing a pulsed laser R, G, B light source of reduced speckle noise useful in a full color display system, which method comprises:
- a) providing a pulsed laser output beam;
- b) generating by crystal-based, non-linear frequency conversion, a G beam with spatial incoherency, by multi-longitudinal mode operation produced by an etalon located in a G-channel cavity, from the output beam;
- c) generating, by optically pumping a Ti:S laser crystal with frequency-doubled output beam radiation to produce an intermediate lasing wavelength and crystal-based, intra-cavity non-linear frequency conversion of the intermediate lasing wavelength, a B beam from the output beam;
- d) generating from the output beam, by crystal-based, non-linear frequency conversion, an intermediate beam having a spectral width substantially greater than a spectral width of the output beam and a wavelength longer than the wavelength of the output beam, and subsequent crystal-based, non-linear sum frequency mixing of the intermediate beam with the output beam an R beam with a spectral width determined by the spectral width of the intermediate beam;
- and
- e) mixing the generated R,G and B beams to provide a full color beam with reduced speckle noise.
3 more elements
Dependencies are inferred from the claim text.