US4499574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Record carrier with an optically readable information structure
Assignee: US Philips Corp
•
Filing: 1979-06-07
•
Granted: 1985-02-12
•
Expires: 1999-06-07
Abstract
Abstract A record carrier is described having an optically readable information structure comprising trackwise arranged information areas which, in the track direction, alternate with intermediate areas, the information being contained in at least the local length of the information areas, of which information structure the average length of the information areas varies. It is demonstrated that by adapting the track period to the average length of the information areas in the tracks, the cross-talk between the tracks may be reduced without essentially reducing the information density.
Inventors
- 👤 Josephus J. M. Braat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:38
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/2407; G11B7/24085; G11B7/24073; G11B7/24079
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
121 words
A record carrier with an optically readable information structure comprising information areas arranged in a plurality of spaced apart tracks and separated from each other in the track direction by intermediate areas, at least the length of said information areas in the track direction varying in accordance with the information contained therein and the width of said information areas in a direction perpendicular to said track direction being substantially constant, the distance between the tracks in a direction normal to said track direction being dependent on the average length of said information areas such that said distance between tracks increases with decreasing average length of said information areas to thereby reduce cross-talk during reading of the information recorded on said carrier.
Claim 2
Dependent Claim
121 words
A record carrier with an optically readable information structure comprising information areas arranged in a plurality of spaced apart tracks and separated from each other in the track direction by intermediate areas, at least the length of said information areas in the track direction varying in accordance with the information contained therein and the width of said information areas in a direction perpendicular to said track direction being substantially constant, the distance between the tracks in a direction normal to said track direction being dependent on the average length of said information areas such that said distance between tracks increases with decreasing average length of said information areas to thereby reduce cross-talk during reading of the information recorded on said carrier.
Claim 3
Dependent Claim
32 words
The record carrier according to claim 1 wherein said tracks are circular and each defines one turn of a spiral formed by said tracks on at least one surface of said carrier.
Claim 4
Dependent Claim
54 words
The record carrier according to claim 1 wherein at least some of said tracks have a first portion containing said information areas and said intermediate areas and a second portion provided with a material which is inscribable with optical radiation, the information areas in said first portion defining an address for said second portion.
Claim 5
Dependent Claim
37 words
A record carrier according to claim 1 wherein said tracks are essentially concentric circles containing substantially equal amounts of information and wherein the distance between the inner tracks is greater than the distance between the outer tracks.
Claim 6
Dependent Claim
29 words
The record carrier according to claim 4 wherein the distance between the inner tracks is approximately 2 μm and the distance between the outer tracks is approximately 1.6 μm.
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) | 1988-02-12 | 1988-08-13 | 1989-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-12 | 1992-08-13 | 1993-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-12 | 1996-08-13 | 1997-02-12 | $7700.00 | Window Closed / Lapsed |