US6040030A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recording medium
Assignee: TDK Corp
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Filing: 1998-09-15
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Granted: 2000-03-21
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Expires: 2018-09-15
Abstract
Abstract A method for recording/reproducing an optical recording medium of phase change type is provided. The method enables a high density recording while increase in the cross erase is suppressed. The method also enables an accurate tracking while increase in the crosstalk is suppressed. The method is adapted for use with an optical recording medium of phase change type comprising a substrate having a thickness of up to 0.8 mm wherein lands and grooves on opposite sides of the land are formed on the surface, and both the lands and the grooves are used as recording tracks, and the medium is overwritten at a recording power Pw (mW) and an erasing power Pe (mW) which meet the relation: (Pw/Pe)×k 2 ≦8.5, when the medium has a recording track pitch P (μm), the recording/reproducing optical system has a numerical aperture NA, and the recording/reproducing light has a wavelength λ (μm) which meet the relation: k=(λ/NA)/P≧1.78.
Inventors
- 👤 Hajime Utsunomiya
- 👤 Tatsuya Kato
- 👤 Hiroyasu Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:11
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/006; G11B7/007; G11B7/00718; G11B7/0045; G11B7/00454; G11B7/0055; G11B7/00557; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10S430/00; Y10S430/146; Y10T; Y10T428/00; Y10T428/21
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
106 words
A method for recording/reproducing an optical recording medium of phase change type comprising a substrate having a thickness of up to 0.8 mm wherein lands and grooves on opposite sides of the land are formed on the surface, and both the lands and the grooves are used as recording tracks, wherein the medium is overwritten at a recording power Pw (mW) and an erasing power Pe (mW) which meet the relation: (Pw/Pe)×k.sup.2 ≦8.5 when the medium has a recording track pitch P (μm), the recording/reproducing optical system has a numerical aperture NA, and the recording/reproducing light has a wavelength λ (μm) which meet the relation: k=(λ/NA)/P≧1.78.
Claim 2
Independent Claim
106 words
A method for recording/reproducing an optical recording medium of phase change type comprising a substrate having a thickness of up to 0.8 mm wherein lands and grooves on opposite sides of the land are formed on the surface, and both the lands and the grooves are used as recording tracks, wherein the medium is overwritten at a recording power Pw (mW) and an erasing power Pe (mW) which meet the relation: (Pw/Pe)×k.sup.2 ≦8.5 when the medium has a recording track pitch P (μm), the recording/reproducing optical system has a numerical aperture NA, and the recording/reproducing light has a wavelength λ (μm) which meet the relation: k=(λ/NA)/P≧1.78.
Claim 3
Dependent Claim
38 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein said groove has a depth d G , and said substrate has a refractive index n at wavelength λ which meet the relation: λ/10n≦d.sub.G <λ/7n.
Claim 4
Dependent Claim
35 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein said groove has a width w G and said land has a width w L which meet the relation: 0.76≦w.sub.L /w.sub.G ≦1.31.
Claim 5
Dependent Claim
14 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein P≦0.65.
Claim 6
Dependent Claim
31 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein said optical recording medium has a reflectance at said wavelength of the recording/reproducing light of up to 17%.
Claim 7
Dependent Claim
56 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein said optical recording medium has a recording layer, and said recording layer has a light absorptivity at said wavelength of the recording/reproducing laser beam such that: Ac/Aa≧0.8 when light absorptivity in crystalline region is Ac and light absorptivity in noncrystalline region is Aa.
Claim 8
Dependent Claim
14 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein λ≦0.68.
Claim 9
Dependent Claim
14 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein NA≧0.6.
Claim 10
Dependent Claim
41 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein said optical recording medium has a ratio in an absolute value of reproduction output of the land to reproduction output of the groove of up to 2 dB.
Claim 11
Dependent Claim
23 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein absolute value of cross erase is up to 0.3 dB.
Claim 12
Dependent Claim
21 words
The method for recording/reproducing an optical recording medium according to claim 1 wherein crosstalk upon reproduction is up to -20 dB.
Claim 13
Dependent Claim
20 words
An optical recording medium which is recorded and reproduced by any one of the methods of claims 1 to 11.
References Cited (Backward Citations)
JPS5750330A
Cited
JPH06338064A
Cited
US5652037A
Cited
US5581539A
Cited
JPH08124218A
Cited
US5848043A
Cited
JPH09204686A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-03-21 | 2003-09-20 | 2004-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-21 | 2007-09-20 | 2008-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-21 | 2011-09-20 | 2012-03-21 | $7700.00 | Window Closed / Lapsed |