Patent US5499229A successfully refreshed from Google Patents.
US5499229A
Expired / Lapsed
US
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Track scanning for reproducing address information by crosstalk
Assignee: Sharp Corp
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Filing: 1994-11-30
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Granted: 1996-03-12
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Expires: 2014-11-30
Abstract
Abstract On an optical disk, information is recorded on both grooves and lands as guide tracks for guiding a light beam. The width of each groove and that of each land are set substantially equal to each other. A plurality of series of pits representing address information are formed in the grooves so that the series of pits in a groove and the series of pits in the adjacent grooves are located in different radial directions of the optical disk. Address pits are not formed in any of the tracks formed by the lands. When the light beam scans the track on the land, the address information is obtained by crosstalk of the series of address pits formed in the track on the groove. This structure enables the management of the addresses of tracks having thereon no address pits. When obtaining the address information by reproducing the series of address pits on the groove, since no crosstalk occurs, accurate address information is obtained.
Inventors
- 👤 Yoshiteru Murakami
- 👤 Akira Takahashi
- 👤 Kenji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:35
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10515; G11B11/1055; G11B11/10576; G11B11/10578; G11B7/00; G11B7/007; G11B7/00718; G11B7/00745; G11B7/08; G11B7/09; G11B7/0938
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
187 words
An optical disk comprising: a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, wherein said grooves and said lands are arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits is formed on the track of either one of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, and each of the series of pits in a radial direction of said disk has such a width that, when the light beam scans a track having no address pits thereon, address information of the track is reproducible by crosstalk of the series of address pits recorded on the adjacent track.
Claim 2
Dependent Claim
187 words
An optical disk comprising: a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, wherein said grooves and said lands are arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits is formed on the track of either one of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, and each of the series of pits in a radial direction of said disk has such a width that, when the light beam scans a track having no address pits thereon, address information of the track is reproducible by crosstalk of the series of address pits recorded on the adjacent track.
Claim 3
Dependent Claim
41 words
The optical disk according to claim 1, wherein said optical disk satisfies a relationship T≦Pw≦2T where T is a track pitch and Pw is a dimension of each of the series of address pits in the radial direction of said disk.
Claim 4
Dependent Claim
20 words
The optical disk according to claim 1, wherein said optical disk is a magneto-optical recording medium for magneto-optically recording information.
Claim 5
Dependent Claim
120 words
The optical disk according to claim 3, wherein said magneto-optical recording medium comprises: a recording layer made of a film having perpendicular magnetization, for magneto-optically recording information; and a readout layer whose Curie temperature is sufficiently higher than a Curie temperature of said recording layer and whose compensation temperature is in a range between room temperature and the Curie temperature thereof, said readout layer having in-plane magnetization in which in-plane magnetic anisotropy is larger than perpendicular magnetic anisotropy at room temperature, and perpendicular magnetization in which perpendicular magnetic anisotropy is larger than in-plane magnetic anisotropy when an area of said readout layer exposed to the light beam by an application of the light beam reaches or exceeds a predetermined temperature.
Claim 6
Dependent Claim
35 words
The optical disk according to claim 1, wherein a center point of each of the series of address pits and a center line of each of said grooves or said lands are out of alignment.
Claim 7
Dependent Claim
20 words
The optical disk according to claim 5, wherein said optical disk is a magneto-optical recording medium for magneto-optically recording information.
Claim 8
Dependent Claim
120 words
The optical disk according to claim 6, wherein said magneto-optical recording medium comprises: a recording layer made of a film having perpendicular magnetization, for magneto-optically recording information; and a readout layer whose Curie temperature is sufficiently higher than a Curie temperature of said recording layer and whose compensation temperature is in a range between room temperature and the Curie temperature thereof, said readout layer having in-plane magnetization in which in-plane magnetic anisotropy is larger than perpendicular magnetic anisotropy at room temperature, and perpendicular magnetization in which perpendicular magnetic anisotropy is larger than in-plane magnetic anisotropy when an area of said readout layer exposed to the light beam by an application of the light beam reaches or exceeds a predetermined temperature.
Claim 9
Independent Claim
224 words
A method for reproducing address information from an optical disk including a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, said grooves and said lands being arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits being formed on the track of either one of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, said method comprising the steps of: applying a light beam to one of the tracks to follow the track; when the light beam scans a track having thereon the series of address pits, reading the address information by a signal obtained from the series of address pits on the track; and when the light beam scans a track having thereon no address pits, reading the address information by a crosstalk signal obtained from the series of address pits on the adjacent track.
Claim 10
Independent Claim
224 words
A method for reproducing address information from an optical disk including a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, said grooves and said lands being arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits being formed on the track of either one of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, said method comprising the steps of: applying a light beam to one of the tracks to follow the track; when the light beam scans a track having thereon the series of address pits, reading the address information by a signal obtained from the series of address pits on the track; and when the light beam scans a track having thereon no address pits, reading the address information by a crosstalk signal obtained from the series of address pits on the adjacent track.
Claim 11
Independent Claim
250 words
A method for reproducing address information from an optical disk including a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, said grooves and said lands being arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits being formed either on the track of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, and a center point of each of the series of address pits and a center line of each of said grooves or said lands being out of alignment, said method comprising the steps of: applying a light beam to one of the tracks to follow the track; when the light beam scans a track having thereon the series of address pits, reading the address information by a signal obtained from the series of address pits on the track; and when the light beam scans a track having thereon no address pits, reading the address information by a crosstalk signal obtained from the series of address pits on the adjacent track.
Claim 12
Independent Claim
250 words
A method for reproducing address information from an optical disk including a substrate having thereon grooves and lands as guide tracks for guiding a light beam, and a series of address pits recorded as address information of said tracks, said grooves and said lands being arranged to have a substantially equal width so as to enable recording of information on both the tracks formed by said grooves and said lands, the series of address pits being formed either on the track of said groove or said land, the series of pits on one of said grooves or lands and the series of pits on the adjacent groove or land are located in different radial directions of said optical disk for preventing the light beam from being simultaneously projected onto a plurality of the series of address pits on different tracks, and a center point of each of the series of address pits and a center line of each of said grooves or said lands being out of alignment, said method comprising the steps of: applying a light beam to one of the tracks to follow the track; when the light beam scans a track having thereon the series of address pits, reading the address information by a signal obtained from the series of address pits on the track; and when the light beam scans a track having thereon no address pits, reading the address information by a crosstalk signal obtained from the series of address pits on the adjacent track.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-12 | 1999-09-11 | 2000-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-12 | 2003-09-11 | 2004-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-12 | 2007-09-11 | 2008-03-12 | $7700.00 | Window Closed / Lapsed |