Patent US1664493A successfully refreshed from Google Patents.
US4556967A
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Record carrier having an optically readable information structure comprised of information areas of two different phase depths
Assignee: US Philips Corp
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Filing: 1983-12-27
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Granted: 1985-12-03
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Expires: 2003-12-27
Abstract
Abstract A record carrier is described which has an optically readable information structure in which information areas of adjacent information track portions have different phase depths, and an apparatus for reading said record carrier. By a suitable choice of the phase depths and by an electronic phase shift of the signals supplied by the read detectors, cross-talk between adjacent tracks can substantially be eliminated.
Inventors
- 👤 Josephus J. M. Braat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:30
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0938; G11B3/00; G11B3/60; G11B7/24; G11B7/2407; G11B7/24085
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
69 words
A record carrier having an information structure which comprises optically readable information areas arranged in generally parallel information tracks, adjacent information track portions differing from each other in that one of said adjacent track portions contains information areas of a first phase depth and the other of said adjacent portions contains information areas of a second phase depth which differs from the first phase depth by approximately π/2 radians.
Claim 2
Dependent Claim
69 words
A record carrier having an information structure which comprises optically readable information areas arranged in generally parallel information tracks, adjacent information track portions differing from each other in that one of said adjacent track portions contains information areas of a first phase depth and the other of said adjacent portions contains information areas of a second phase depth which differs from the first phase depth by approximately π/2 radians.
Claim 3
Dependent Claim
25 words
A record carrier as claimed in claim 1 wherein the first phase depth is approximately 5π/4 radians and the second phase depth approximately 3π/4 rad.
Claim 4
Dependent Claim
48 words
The record carrier according to claim 1 wherein said adjacent track portions are arranged such that one portion containing information areas of the first phase depth in a given track is disposed next to another portion containing information areas of the second phase depth in an adjacent track.
Claim 5
Dependent Claim
48 words
A record carrier as claimed in claim 1, 2 or 3 wherein in addition to an information signal a pilot signal is recorded, which pilot signal indicates the transitions between information areas of the first phase depth and information areas of the second phase depth, and vice versa.
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) | 1988-12-02 | 1989-06-03 | 1989-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-02 | 1993-06-03 | 1993-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-02 | 1997-06-03 | 1997-12-03 | $7700.00 | Window Closed / Lapsed |