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Optical pickup, aberration correction unit and astigmatism measurement method

  • US 6,151,154 A
  • Filed: 03/11/1999
  • Issued: 11/21/2000
  • Est. Priority Date: 03/12/1998
  • Status: Expired due to Term
First Claim
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1. An optical pickup comprising:

  • a light source for emitting a light beam;

    an object lens for processing the light beam from the light source; and

    aberration correction means for correcting aberration by giving a phase difference to the light beam, said aberration correction means correcting astigmatism caused by an optical system of said optical pickup, said aberration correction means having an area substantially corresponding to a wave front aberration distribution of the astigmatism, optical properties of the area being changed so as to cancel the astigmatism.

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