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Magneto-optical disk system with specified thickness for protective layer on the disk relative to the numerical aperture of the objective lens - Patent US5392263(A)

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Filed: Jul 19, 1994
Published: Feb 21, 1995

Abstract

A magneto-optical disc system includes a magneto-optical disc with a light transmitting protective layer, an objective lens for bundling or focusing a laser beam onto a magnetic recording layer of the magneto-optical disc in order to perform recording and/or reproduction, and a magnetic field generating unit formed as a coil pattern on a transparent optical glass layer. In the magneto-optical disc system, the thickness t2 of the light-transmitting protective layer is set to fall within the range of 0.6 to 1.0 mm and the numerical aperture of the objective lens is set to fall within the range of 0.55 to 0.70, so as to obtain high density recording and/or reproduction by permitting the lens to be quite close to the actual recording layer.

Applicants

  • SONY CORP

Inventors

  • WATANABE TETSU
  • AOKI YOSHIO

Application Number

277357

Priority Claims

US76187491

Family Members

US5392263(A) - Magneto-optical disk system with specified thickness for protective layer on the disk relative to the numerical aperture of the objective lens

Classification Codes

G11B7/24, G11B7/07, G11B7/37, G11B11/105, G11B7/00, G11B7/125, G11B11/00, G11B7/135
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