US5119355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical information processing apparatus
Assignee: Sharp Corp
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Filing: 1990-04-05
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Granted: 1992-06-02
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Expires: 2010-04-05
Abstract
Abstract An optical information processing apparatus which includes a substrate of a transparent material, first and second optical waveguides formed on opposite faces of said transparent substrate, a light introducing device for introducing reflected light from an information writing medium into the first and second optical waveguides, and a detecting device for detecting a reproduction signal, tracking error signal and focusing error signal based on the reflected light introduced into the first and second optical waveguides.
Inventors
- 👤 Osamu Yamamoto
- 👤 Toshihiko Yoshida
- 👤 Saburo Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:39
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1384; G11B7/123; G11B7/124
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
165 words
An optical information processing apparatus for recording to and reproducing information from an optical recording medium having a plurality of substantially aligned and radially extending tracks by disposing an information bearing light on said tracks, the apparatus comprising: a substrate, an optical waveguide formed on said substrate, light division means for dividing light reflected by said recording medium through said optical waveguide into first and second converging light beams, a first three-division photo-detector disposed before a focal point of said first converging light beam from said light division means for receiving said first converging light and producing a signal in response thereto, and a second three-division photo-detector disposed after the focal point of said second converging light beam for receiving said second converging light beam and producing a signal in response thereto, and differentiation means for receiving the signals produced by said first and second three-division photo-detectors and for producing a focusing error through comparison of the differentiation between said first and second three-division photo-detectors.
Claim 2
Dependent Claim
165 words
An optical information processing apparatus for recording to and reproducing information from an optical recording medium having a plurality of substantially aligned and radially extending tracks by disposing an information bearing light on said tracks, the apparatus comprising: a substrate, an optical waveguide formed on said substrate, light division means for dividing light reflected by said recording medium through said optical waveguide into first and second converging light beams, a first three-division photo-detector disposed before a focal point of said first converging light beam from said light division means for receiving said first converging light and producing a signal in response thereto, and a second three-division photo-detector disposed after the focal point of said second converging light beam for receiving said second converging light beam and producing a signal in response thereto, and differentiation means for receiving the signals produced by said first and second three-division photo-detectors and for producing a focusing error through comparison of the differentiation between said first and second three-division photo-detectors.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |