US3909517A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disc records with groove bottom depth variations
Assignee: RCA Corp
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Filing: 1973-12-03
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Granted: 1975-09-30
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Expires: 1993-12-03
Abstract
Abstract An information record employs a storage medium comprising a metallized base material having a dielectric coating thereon. The dimensions of an information track contained in a groove in the storage medium vary in accordance with recorded information pursuant to an information-representative pattern of relatively raised and depressed areas, the former constituting undisturbed regions of the groove bottom. The information track may comprise (1) an AM carrier pattern wherein a carrier frequency amplitude modulated by the video signals is represented by successive pairs of regions, a first region of each pair having the relative widths of a central depressed area and adjoining raised areas determined by video signal amplitude, and the succeeding region of each pair having the relative widths of a central raised area and adjoining depressed areas complementarily determined; or (2) a FM carrier pattern, wherein depressed areas extending across the width of the groove bottom alternate with raised areas extending across the width of the groove bottom, and the spacing between successive areas of the same type varies with video signal amplitude. The capacitance between an electrode in a pickup tracking in said groove and the metallized surface of the storage medium varies in accordance with the modulated information track as the pickup device scans the recording medium. Circuitry responding to said capacitance variations provides an output signal corresponding to the information recorded. One application of such a system is to record, on both sides of a disc, video information which can be reproduced in form of a video display.
Inventors
- 👤 Jon Kaufmann Clemens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:03
CPC Classifications
G; G11; G11B; G11B9/00; G11B9/06; G11B9/061; G11B11/00; G11B11/03; G11B11/05; H; H04; H04N; H04N5/00; H04N5/76; H04N5/7605; H04N5/903
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
361 words
A disc record having a spiral groove in a surface thereof; said spiral groove containing an information track in the bottom of said groove including (1) first recurring regions regularly spaced along the length of the successive convolutions of the spiral, in each of which at least a portion of the groove bottom area is depressed to a maximum depth, with the remainder, if any, of the groove bottom area in each first region raised relative to said maximum depth, and (2) second regions, separating said first regions, in each of which at least a portion of the groove bottom area is raised relative to said maximum depth, with the remainder, if any, of the groove bottom area in each second region depressed to said maximum depth; the percentage of groove bottom area in each first region which is subject to depression to said maximum depth varying in accordance with recorded information, with the percentage of groove bottom area in an adjoining second region which is subject to depression to said maximum depth varying complementarily so that the percentage of groove bottom area raised relative to said maximum depth in successive pairs of first and second regions remains substantially constant and independent of recorded information; wherein the groove bottom portion which is depressed to said maximum depth in each of said first recurring regions is centrally located relative to the sides of said groove; wherein the groove bottom portion which is raised relative to said maximum depth in each of said second recurring regions is centrally located relative to the sides of said groove; wherein said spiral groove has respective sidewalls of substantially invariant geometry throughout successive convolutions of the spiral; wherein the groove cross-section in each of said first recurring regions has a shape such that the surfaces of the respective groove sidewalls and said raised remainder of the groove bottom area define respective sections of a continuous smooth curve; and wherein the groove cross-section in each of said second recurring regions has a shape such that the surfaces of the respective groove sidewalls and said centrally located, raised groove bottom portion define respective sections of a continuous smooth curve.
Claim 2
Dependent Claim
361 words
A disc record having a spiral groove in a surface thereof; said spiral groove containing an information track in the bottom of said groove including (1) first recurring regions regularly spaced along the length of the successive convolutions of the spiral, in each of which at least a portion of the groove bottom area is depressed to a maximum depth, with the remainder, if any, of the groove bottom area in each first region raised relative to said maximum depth, and (2) second regions, separating said first regions, in each of which at least a portion of the groove bottom area is raised relative to said maximum depth, with the remainder, if any, of the groove bottom area in each second region depressed to said maximum depth; the percentage of groove bottom area in each first region which is subject to depression to said maximum depth varying in accordance with recorded information, with the percentage of groove bottom area in an adjoining second region which is subject to depression to said maximum depth varying complementarily so that the percentage of groove bottom area raised relative to said maximum depth in successive pairs of first and second regions remains substantially constant and independent of recorded information; wherein the groove bottom portion which is depressed to said maximum depth in each of said first recurring regions is centrally located relative to the sides of said groove; wherein the groove bottom portion which is raised relative to said maximum depth in each of said second recurring regions is centrally located relative to the sides of said groove; wherein said spiral groove has respective sidewalls of substantially invariant geometry throughout successive convolutions of the spiral; wherein the groove cross-section in each of said first recurring regions has a shape such that the surfaces of the respective groove sidewalls and said raised remainder of the groove bottom area define respective sections of a continuous smooth curve; and wherein the groove cross-section in each of said second recurring regions has a shape such that the surfaces of the respective groove sidewalls and said centrally located, raised groove bottom portion define respective sections of a continuous smooth curve.
Claim 3
Dependent Claim
127 words
A disc record having a spiral groove in a surface thereof; said spiral groove having respective curved sidewalls of substantially invariant geometry throughout successive convolutions of the spiral; the groove cross-section alternating along said groove between a first recurring shape in which the curved surfaces of the respective groove sidewalls and the intervening groove bottom define a continUous smooth curve and a second recurring shape in which the surface of said intervening groove bottom is depressed relative to the groove bottom level associated with the definition of said continuous smooth curve for said first shape; the frequency of occurrence of the alternations of the groove cross-section between said first shape and said second shape along the length of said spiral groove varying in accordance with recorded information.
Claim 4
Dependent Claim
127 words
A disc record having a spiral groove in a surface thereof; said spiral groove having respective curved sidewalls of substantially invariant geometry throughout successive convolutions of the spiral; the groove cross-section alternating along said groove between a first recurring shape in which the curved surfaces of the respective groove sidewalls and the intervening groove bottom define a continUous smooth curve and a second recurring shape in which the surface of said intervening groove bottom is depressed relative to the groove bottom level associated with the definition of said continuous smooth curve for said first shape; the frequency of occurrence of the alternations of the groove cross-section between said first shape and said second shape along the length of said spiral groove varying in accordance with recorded information.
References Cited (Backward Citations)
US3652809A
Cited
US3798388A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |