US5422874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recording disk, and recording/reading apparatus using same
Assignee: Panasonic Holdings Corp
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Filing: 1993-09-09
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Granted: 1995-06-06
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Expires: 2013-09-09
Abstract
Abstract The present invention relates to a magneto-optical recording medium, in which are provided at least a reading layer and a writing layer on a substrate. A track guide groove is formed in the medium so as to include in-groove portions and on-land portions. Pits are formed on a portion along the track longitudinally adjacent where an in-groove portion and where no guide groove exists. Pits are also formed in an on-land portion between the in-groove portions of the track guide groove. Only a portion where a temperature has been raised by optical beam irradiation is read, while a domain of a writing layer is copied on the writing layer, whereby a writing/reading operation can be effected with narrower track pitches.
Inventors
- 👤 Masahiro Birukawa
- 👤 Norio Miyatake
- 👤 Yuuichi Fukamachi
- 👤 Yoshihiko Kudoh
- 👤 Yasumori Hino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:35
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10584; G11B11/10502; G11B11/10515; G11B11/1055; G11B11/10556; G11B11/10563; G11B11/10576; G11B11/10578; G11B20/00; G11B20/10; G11B20/12; G11B20/1217; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; G11B7/00; G11B7/007; G11B7/00718; G11B7/00745; G11B7/24; G11B7/26; G11B7/261
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
178 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into a plurality of sector portions; wherein a first plurality of said sector portions comprises land sector portions and a second plurality of said sector portions comprises groove sector portions; wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction; wherein each of said groove sector portions comprises a groove area and a non-groove area, and each of said land sector portions comprises a land constituting a non-groove area; wherein each of said land sector portions includes a read-only area comprising pits, and a rewriting area for recording and reading of data; wherein each of said groove sector portions includes a read-only area comprising pits, and a rewriting area for recording and reading of data; wherein said read-only area of each of said groove sector portions is formed in said non-groove area thereof; and wherein said read-only area of each of said land sector portions is formed in said non-groove area thereof.
Claim 2
Dependent Claim
178 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into a plurality of sector portions; wherein a first plurality of said sector portions comprises land sector portions and a second plurality of said sector portions comprises groove sector portions; wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction; wherein each of said groove sector portions comprises a groove area and a non-groove area, and each of said land sector portions comprises a land constituting a non-groove area; wherein each of said land sector portions includes a read-only area comprising pits, and a rewriting area for recording and reading of data; wherein each of said groove sector portions includes a read-only area comprising pits, and a rewriting area for recording and reading of data; wherein said read-only area of each of said groove sector portions is formed in said non-groove area thereof; and wherein said read-only area of each of said land sector portions is formed in said non-groove area thereof.
Claim 3
Dependent Claim
69 words
A rewritable disk-shaped optical recording medium as recited in claim 1, wherein said track is a spiral track, and said turns thereof comprise a plurality of first turns and a plurality of second turns alternating contiguous with said first turns; each of said first turns comprises a contiguous plurality of said groove sector portions; and each of said second turns comprises a contiguous plurality of said land sector portions.
Claim 4
Dependent Claim
34 words
A rewritable disk-shaped optical recording medium as recited in claim 2, further comprising a discrimination part comprising pits for providing an indication of junctions between circumferentially contiguous ones of said first and second turns.
Claim 5
Dependent Claim
72 words
A rewritable disk-shaped optical recording medium as recited in claim 1, further comprising a reading layer comprising at least one magnetic film, and a writing layer; and wherein said reading layer and said writing layer constitute a transfer means for transferring, by exchange coupling, a magnetic domain written on said writing layer from said writing layer to said reading layer, at a location heated by irradiation of a laser beam during reading.
Claim 6
Dependent Claim
87 words
A rewritable disk-shaped optical recording medium as recited in claim 1, wherein said track is a spiral track, and said turns thereof comprise a plurality of first turns and a plurality of second turns alternatingly contiguous with said first turns; each of said first turns comprises a plurality of said groove sector portions alternatingly contiguous with a plurality of said land sector portions; and each of said second turns comprises a plurality of said land sector portions alternatingly contiguous with a plurality of said groove sector portions.
Claim 7
Dependent Claim
33 words
A rewritable disk-shaped optical recording medium as recited in claim 1, wherein for each of said groove sector portions, said non-groove area is positioned along a circumferential extension line of said groove area.
Claim 8
Dependent Claim
38 words
A rewritable disk-shaped optical recording medium as recited in claim 1, wherein for each of said groove sector portions and said land sector portions, said read-only area is positioned along a circumferential extension line of said rewriting area.
Claim 9
Dependent Claim
109 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into an odd number of sector portions; wherein a first plurality of said sector portions comprises land sector portions respectively comprising lands which constitute non-groove areas, and a second plurality of said sector portions comprises groove sector portions respectively comprising groove areas; wherein each of said land sector portions and said groove sector portions comprises a rewriting area for recording and reading of data; and wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction and are alternatingly provided along a circumferential direction.
Claim 10
Dependent Claim
109 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into an odd number of sector portions; wherein a first plurality of said sector portions comprises land sector portions respectively comprising lands which constitute non-groove areas, and a second plurality of said sector portions comprises groove sector portions respectively comprising groove areas; wherein each of said land sector portions and said groove sector portions comprises a rewriting area for recording and reading of data; and wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction and are alternatingly provided along a circumferential direction.
Claim 11
Dependent Claim
30 words
A rewritable disk-shaped optical recording medium as recited in claim 8, wherein each of said land sector portions and said groove sector portions further comprises a read-only area comprising pits.
Claim 12
Dependent Claim
38 words
A rewritable disk-shaped optical recording medium as recited in claim 9, wherein for each of said groove sector portions and said land sector portions, said read-only area is positioned along a circumferential extension line of said rewriting area.
Claim 13
Dependent Claim
32 words
A rewritable disk-shaped optical recording medium as recited in claim 8, wherein each of said groove sector portions further comprises a non-groove area, said read-only area being formed in said non-groove area.
Claim 14
Dependent Claim
156 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into an odd number of sector portions; wherein a first plurality of said sector portions comprises land sector portions respectively comprising lands which constitute non-groove areas, and a second plurality of said sector portions comprises groove sector portions respectively comprising groove areas; wherein each of said land sector portions and said groove sector portions comprises a rewriting area for recording and reading of data; wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction and are alternatingly provided along a circumferential direction; wherein each sector portion includes a read-only area, comprising pits, provided as a sector mark which indicates a starting point of each sector portion; and wherein, for each turn of said track, said read-only area of each sector portion has a length less than 1/2000 of the turn.
Claim 15
Dependent Claim
156 words
A rewritable disk-shaped optical recording medium, comprising: a track having a plurality of turns, each of which is divided into an odd number of sector portions; wherein a first plurality of said sector portions comprises land sector portions respectively comprising lands which constitute non-groove areas, and a second plurality of said sector portions comprises groove sector portions respectively comprising groove areas; wherein each of said land sector portions and said groove sector portions comprises a rewriting area for recording and reading of data; wherein said land sector portions and said groove sector portions are alternatingly provided along a radial direction and are alternatingly provided along a circumferential direction; wherein each sector portion includes a read-only area, comprising pits, provided as a sector mark which indicates a starting point of each sector portion; and wherein, for each turn of said track, said read-only area of each sector portion has a length less than 1/2000 of the turn.
Claim 16
Dependent Claim
26 words
A rewritable disk-shaped optical recording medium as recited in claim 12, wherein said read-only area of each sector portion has a length less than ten bytes.
Claim 17
Dependent Claim
34 words
A rewritable disk-shaped optical recording medium as recited in claim 12, wherein a depth of said pits of each of said read-only areas is equal to a depth of each of said groove areas.
Claim 18
Dependent Claim
47 words
A rewritable disk-shaped optical recording medium as recited in claim 14, wherein said depth of said pits and said groove areas is greater than λ/30 and less than λ/14, where λ is the wavelength of a laser beam employed in reading and recording data of said medium.
Claim 19
Dependent Claim
34 words
A rewritable disk-shaped optical recording medium as recited in claim 12, wherein said sector marks comprise discrimination parts for indicating starting points of said sector portions, respectively, and for changing a polarity of tracking.
Claim 20
Dependent Claim
72 words
A rewritable disk-shaped optical recording medium as recited in claim 12, further comprising a reading layer comprising at least one magnetic film, and a writing layer; and wherein said reading layer and said writing layer constitute a transfer means for transferring, by exchange coupling, a magnetic domain written on said writing layer from said writing layer to said reading layer, at a location heated by irradiation of a laser beam during reading.
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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) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-05 | 2002-12-05 | 2003-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-05 | 2006-12-05 | 2007-06-06 | $7700.00 | Window Closed / Lapsed |