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AssigneeHitachi, Ltd.
InventorsKouji Arikawa, Shigeru Nakamura, Kazuo Shigematsu
Estimating the term…
In an optical head for recording on or reproducing from a plurality of kinds of optical information recording media corresponding to a plurality of kinds of different wavelengths, coma aberration is prevented, and low price and high reliability are realized. To that end, in an optical head constituted by laser light sources of three wavelengths and photodetectors corresponding to the laser light sources of the three wavelengths, a two-laser module including laser light sources of two adjacent wavelengths and photodetectors corresponding to the laser light sources, a laser module including a laser light source of the rest one wavelength and a photodetector corresponding to the laser light source, and a dichroic mirror bonded with a rising mirror are combined.
An optical head comprising a plurality of laser light sources and a plurality of photodetectors corresponding to said plurality of laser light sources, wherein said plurality of laser light sources have three kinds of wavelengths A, B and C (A>B>C), and include first and second laser modules, said first laser module including laser light sources having the wavelengths A and B and two photodetectors corresponding to said laser light sources having the wavelengths A and B, said second laser module including a laser light source having the wavelength C and a photodetector corresponding to said laser light source having the wavelength C, wherein laser light emitted from each laser light source of said first laser module is introduced to an optical information medium through a wavelength filter, reflected light from said optical information medium is introduced to said photodetectors of said first laser module, and wherein laser light emitted from said laser light source of said second laser module is introduced to said optical information medium through said wavelength filter, reflected light from said optical information medium is introduced to said photodetector of said second laser module.
An optical head comprising a plurality of laser light sources and a plurality of photodetectors corresponding to said plurality of laser light sources, wherein said plurality of laser light sources have three kinds of wavelengths A, B and C (A>B>C), and include first and second laser modules, said first laser module including laser light sources having the wavelengths B and C and two photodetectors corresponding to said laser light sources having the wavelengths B and C, said second laser module including a laser light source having the wavelength A and a photodetector corresponding to said laser light source having the wavelength A, wherein laser light emitted from each laser light source of said first laser module is introduced to an optical information medium through a wavelength filter, reflected light from said optical information medium is introduced to said photodetectors of said first laser module, and wherein laser light emitted from said laser light source of said second laser module is introduced to an optical information medium through said wavelength filter, reflected light from said optical information medium is introduced to said photodetector of said second laser module.
An optical information recording and reproducing apparatus for recording information on an optical information medium or reproducing information recorded thereon, comprising:
An optical information recording and reproducing apparatus for recording information on an optical information medium or reproducing information recorded thereon, comprising:
Dependencies are inferred from the claim text.