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Optical pick-up head apparatus wherein hollographic optical element and photodetector are formed on semiconductor substrate

  • US 5,293,038 A
  • Filed: 03/23/1993
  • Issued: 03/08/1994
  • Est. Priority Date: 04/08/1992
  • Status: Expired due to Term
First Claim
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1. An optical pick-up head apparatus comprising:

  • a semiconductor laser source for emitting a coherent or semimonochromatic beam;

    first reflection means for reflecting said beam from said semiconductor laser source to change the advancing direction of said beam therefrom;

    second reflection means for reflecting the beam reflected on said first reflection means to change the advancing direction thereof;

    third reflection means for reflecting the beam reflected on said second reflection means to change the advancing direction thereof;

    a converging optical system for receiving the beam reflected on said third reflection means to focus the beam on a microscopic spot on an optical storage medium;

    a reflection type holographic optical element for receiving the beam reflected and diffracted on said optical storage medium to generate a diffraction beam; and

    a photodetector having a plurality of photodetecting elements to receive said diffraction beam from said reflection type holographic optical element to generate a photoelectric conversion signal,wherein said laser source is formed on a first semiconductor substrate so that said beam from said laser source is emitted in a direction substantially parallel to a surface of said first semiconductor substrate, said reflection type holographic optical element is formed in said third reflection means, said diffraction beam from said reflection type holographic optical element is incident on said photodetector after being reflected on said second reflection means, said first reflection means, said third reflection means and said photodetector are formed on a second semiconductor substrate, a light-receiving surface of said photodetector is arranged to be substantially parallel to a surface of said second semiconductor substrate, and said surface of said first semiconductor substrate is disposed to be substantially parallel to said surface of said second semiconductor substrate.

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