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EP0294242A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Record face identifying device for optical magnetic record medium

Assignee: Sharp Corp
•
Filing: 1988-06-06
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Granted: —
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Expires: 2008-06-06
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Abstract

Abstract In an optical magnetic record signal processing system in which a linearly polarized light beam is projected on an optical magnetic medium and a recorded signal is reproduced by using polarized conditions of a reflected light beam from the medium, the processing system includes a novel type of record face identifying device for the optical magnetic record medium according to the invention comprising: an initialized area projecting means which projects a light beam on an initialized area of an optical magnetic record medium; a transducing means which converts a slant of a polarization plane of a reflected light beam from the initialized area (5, 7) into a light intensity; a photo-detecting means (9, 13, 14) which detects the light intensity outputted from the transducing means; a comparing means (11, 17) which compares an output from the photo-detecting means with a reference level.

Inventors

  • 👤 Hiroshi Fuji
  • 👤 Tsuneo Fujiwara
  • 👤 Tomiyuki Numata
  • 👤 Kentaroh Tsuji
  • 👤 Iwaki Takashi
  • 👤 Deguchi Toshihisa

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-29 20:36
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10595; G11B11/10597

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 129 words
In an optical magnetic record signal processing system in which a linearly polarized light beam is projected on an optical magnetic record medium and a recorded signal is reproduced by using polarized conditions of a reflected light beam from the medium, said processing system includes a record face identifying device for the optical magnetic record medium comprising: an initialized area projecting means which projects a light beam on an initialized area of an optical magnetic record medium; a transducing means which converts a slant of a polarization plane of a reflected light beam from said initialized area into a light intensity; a photo-detecting means which detects said light intensity outputted from said transducing means; a comparing means which compares an output from said photo-detecting means with a reference level.
Claim 2
Dependent Claim 129 words
In an optical magnetic record signal processing system in which a linearly polarized light beam is projected on an optical magnetic record medium and a recorded signal is reproduced by using polarized conditions of a reflected light beam from the medium, said processing system includes a record face identifying device for the optical magnetic record medium comprising: an initialized area projecting means which projects a light beam on an initialized area of an optical magnetic record medium; a transducing means which converts a slant of a polarization plane of a reflected light beam from said initialized area into a light intensity; a photo-detecting means which detects said light intensity outputted from said transducing means; a comparing means which compares an output from said photo-detecting means with a reference level.
Claim 3
Dependent Claim 46 words
An optical magnetic record signal processing system in which the initialized direction of magnetization of an opto-magnetic recording medium is determined by projecting a polarized light beam onto a predetermined portion of the medium and detecting a rotation of the polarization plane caused by said magnetization.
Claim 4
Dependent Claim 46 words
An optical magnetic record signal processing system in which the initialized direction of magnetization of an opto-magnetic recording medium is determined by projecting a polarized light beam onto a predetermined portion of the medium and detecting a rotation of the polarization plane caused by said magnetization.

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