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EP0311463A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

An optical information reproducing apparatus

Assignee: Sharp Corp
•
Filing: 1988-10-10
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Granted: —
•
Expires: 2008-10-10
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Abstract

Abstract An optical information-reproducing apparatus comprising a light emitting means (11), and an optical system (13) that focuses light emitted from the light emitting means on a recording medium (14) and that detects the reflected light from the recording medium to supply to a diffracting element (12), and a photodetector (15) that includes a plurality of photodetecting portions (15a,b,c,d) divided by division lines and that converts the diffracted light from the diffracting element focussed on the division lines into an electrical signal by the photodetecting portions on both sides of the division lines, wherein the photodetector is so constructed that division lines on which diffracted light from the diffracting element is focused are inclined with respect to the direction of the diffraction of the reflected light in the diffracting element such that the amount of focusing spot light received by the photodetecting portions on both sides of the division lines become substantially equal.

Inventors

  • 👤 Yoshio Yoshida
  • 👤 Toshiya Nagahama
  • 👤 Katuhiro Kubo
  • 👤 Yukio Kurata

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-26 12:30
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/13; G11B7/133; G11B7/135; G11B7/1353

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 182 words
An optical information-reproducing apparatus comprising a light emitting means, and an optical system that focuses light emitted from the light emitting means on a recording medium and that detects the reflected light from said recording medium to supply to a diffracting element, said diffracting element being disposed on an optical axis of the reflected light from said recording medium and having two or more separate regions to diffract the reflected light onto the corresponding division lines of a photodetector, and said photodetector including a plurality of photodetecting portions divided by said division lines, and converting the diffracted light from said diffracting element focused on said division lines into an electrical signal by said photodetecting portions on both sides of said division lines, wherein said photodetector is so constructed that division lines on which diffracted light from said diffracting element is focused are inclined with respect to the direction of the diffraction of the reflected light from said diffracting element such that the amount of focusing spot light received by the photodetecting portions on both sides of said division lines become substantially equal.
Claim 2
Dependent Claim 182 words
An optical information-reproducing apparatus comprising a light emitting means, and an optical system that focuses light emitted from the light emitting means on a recording medium and that detects the reflected light from said recording medium to supply to a diffracting element, said diffracting element being disposed on an optical axis of the reflected light from said recording medium and having two or more separate regions to diffract the reflected light onto the corresponding division lines of a photodetector, and said photodetector including a plurality of photodetecting portions divided by said division lines, and converting the diffracted light from said diffracting element focused on said division lines into an electrical signal by said photodetecting portions on both sides of said division lines, wherein said photodetector is so constructed that division lines on which diffracted light from said diffracting element is focused are inclined with respect to the direction of the diffraction of the reflected light from said diffracting element such that the amount of focusing spot light received by the photodetecting portions on both sides of said division lines become substantially equal.
Claim 3
Dependent Claim 55 words
An optical information-reproducing apparatus accord­ing to claim 1, wherein said photodetector is divided into a plurality of photodetecting portions by a division line that is orthogonal to the direction of the diffraction of said diffracting element and by division lines that are inclined with respect to the direction of the diffraction of said diffracting element.
Claim 4
Dependent Claim 39 words
An optical information-reproducing apparatus accord­ing to claim 1, wherein said photodetector is divided into a plurality of photodetecting portions by said division lines such that said photodetecting portions are disposed in parallel in one direction on the same plane.

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