US4636628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optically recorded data reading apparatus with inclination controller
Assignee: Pioneer Corp
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Filing: 1985-01-23
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Granted: 1987-01-13
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Expires: 2005-01-23
Abstract
Abstract An apparatus for reading optically recorded data from a disk in which diffracted light beams, which otherwise would be applied to light-detecting elements and which are of higher order than the positive and negative first-order diffracted light beams, are eliminated and only a zeroth-order diffracted light beam is applied to the light-detecting elements. Thereby, a tilt control signal is produced whereby a tilt servo operation can be carried out with a high accuracy. Several different structural arrangements are disclosed for achieving the desired blocking of the higher-than-zeroth-order diffracted light beams.
Inventors
- 👤 Yoshiyuki Tsukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:55
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/095; G11B7/0956
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
130 words
In an optical recorded data reading apparatus having a servo system for maintaining the optical axis of a recorded data reading light beam perpendicular to the recording surface of a recording medium, said servo system including inclination controlling means for detecting a deviation of an angle between said optical axis and said recording surface from 90° to control said angle according to the deviation thus detected, the improvement wherein said inclination controlling means comprises: light-emitting means for emitting a light beam towards said recording surface; and light-detecting means receiving said light beam reflected from said recording surface, said light-emitting means and said light-detecting means being positioned so that, of diffracted light beams reflected from said recording surface, substantially only a zeroeth-order diffracted light beam is applied to said light-detecting means.
Claim 2
Dependent Claim
130 words
In an optical recorded data reading apparatus having a servo system for maintaining the optical axis of a recorded data reading light beam perpendicular to the recording surface of a recording medium, said servo system including inclination controlling means for detecting a deviation of an angle between said optical axis and said recording surface from 90° to control said angle according to the deviation thus detected, the improvement wherein said inclination controlling means comprises: light-emitting means for emitting a light beam towards said recording surface; and light-detecting means receiving said light beam reflected from said recording surface, said light-emitting means and said light-detecting means being positioned so that, of diffracted light beams reflected from said recording surface, substantially only a zeroeth-order diffracted light beam is applied to said light-detecting means.
Claim 3
Dependent Claim
43 words
The apparatus as claimed in claim 1, wherein said light-emitting means and said light-detecting means are positioned so that said emitted light beam and said reflected light beam do not pass through a focusing lens provided for said recorded data reading light beam.
Claim 4
Dependent Claim
22 words
The apparatus as claimed in claim 1, wherein said light-detecting means comprises first and second light detectors spaced apart from one another.
Claim 5
Dependent Claim
79 words
The apparatus as claimed in claim 3, wherein an optical axis of said beam emitted by said light-emitting means is substantially parallel to said recording surface, and further comprising a half-silvered mirror disposed so as to reflect said beam emitted by said light-emitting means towards said recording surface and pass a reflected beam towards said first and second light detectors, said first and second light detectors having lcmght-sensing surfaces lying in a plane substantially parallel to said recording surface.
Claim 6
Dependent Claim
76 words
The apparatus as claimed in claim 3, wherein said light beam emitted by said light-emitting means is substantially perpendicular to said recording surface, wherein said first and second light detectors are disposed on opposite sides of said light-emitting means, and further comprising a light-absorbing member disposed between said light-emitting means and said recording surface disposed at a position so as to block all but said zeroeth-order light beam from reaching said first and second light detectors.
Claim 7
Dependent Claim
76 words
The apparatus as claimed in claim 3, wherein said light beam emitted by said light-emitting means is substantially perpendicular to said recording surface, wherein said first and second light detectors are disposed on opposite sides of said light-emitting means, and further comprising a prism disposed between said light-emitting means and said recording surface and disposed at a position so as to block all but said zeroeth-order light beam from reaching said first and second light detectors.
Claim 8
Dependent Claim
66 words
The apparatus as claimed in claim 3, wherein said first and second light detectors are disposed on opposite sides of said light-emitting means, and wherein the height of said light-emitting means above the respective light-sensitive surfaces of said first and second light detectors is sufficient to block all but said zeroeth-order light beam reflected from said recording surface from reaching said first and second light detectors.
Claim 9
Dependent Claim
34 words
The apparatus as claimed in claim 3, wherein said light-emitting means is offset in a track direction of said recording medium from a line joining centers of said first and second light detecting elements.
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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |