Patent US5481530A successfully refreshed from Google Patents.
US5481530A
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High density optical recording method and recording medium
Assignee: Mitsubishi Chemical Media Co Ltd
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Filing: 1993-10-18
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Granted: 1996-01-02
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Expires: 2013-10-18
Abstract
Abstract Disclosed herein are an optical recording method of conducting recording/reading out for information by irradiating a laser beam at a wavelength of not more than 500 nm onto a recording layer of an optical disc having a track pitch of not less than 0.4 mu m and less than 0.9 mu m, the laser beam being incident from a disc substrate side of the optical disc using an objective lens having numerical aperture of 0.55 to 0.70, a recording area for information recording on the disc substrate being a flat area not having a guide groove for each track, and the disc substrate having a in-plane birefringence of not more than 20x10-6 and a vertical birefringence of not more than 300x10-6, and an optical recording medium suitable for use in the optical recording method.
Inventors
- 👤 Chiga Ueda
- 👤 Hidemi Yoshida
- 👤 Masaaki Mizuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:18
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0938; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10593; G11B7/24; G11B7/2407; G11B7/24073; G11B7/24079; G11B7/241; G11B7/252; G11B7/253; G11B7/2533; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24304; G11B7/2433; G11B7/2531; G11B7/2534; G11B7/257; G11B7/2578; G11B7/258; G11B7/259; G11B7/2595
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
128 words
An optical recording method of conducting recording/reading out for information by irradiating a laser beam at a wavelength of not more than 500 nm onto a recording layer of an optical disc comprising a disc substrate and a recording layer, and having a track pitch of not less than 0.4 μm and less than 0.9 μm, a recording area for information recording on the disc substrate being a flat area not having a guide groove for each track, and the disc substrate having an in-plane birefringence of not more than 20×10 -6 and a vertical birefringence of not more than 300×10 -6 . the laser beam being incident from a disc substrate side of the optical disc using an objective lens having numerical aperture of 0.55 to 0.70.
Claim 2
Dependent Claim
128 words
An optical recording method of conducting recording/reading out for information by irradiating a laser beam at a wavelength of not more than 500 nm onto a recording layer of an optical disc comprising a disc substrate and a recording layer, and having a track pitch of not less than 0.4 μm and less than 0.9 μm, a recording area for information recording on the disc substrate being a flat area not having a guide groove for each track, and the disc substrate having an in-plane birefringence of not more than 20×10 -6 and a vertical birefringence of not more than 300×10 -6 . the laser beam being incident from a disc substrate side of the optical disc using an objective lens having numerical aperture of 0.55 to 0.70.
Claim 3
Dependent Claim
16 words
An optical recording method according to claim 1, wherein the disc substrate is a plastic substrate.
Claim 4
Dependent Claim
16 words
An optical recording method according to claim 1, wherein the disc substrate has pits for tracking.
Claim 5
Dependent Claim
18 words
An optical recording method according to claim 3, wherein the tracking is conducted by a sampled servo system.
Claim 6
Dependent Claim
23 words
An optical recording method according to claim 1, wherein a non-reflective coating layer is disposed on a laser-incident surface of the disc substrate.
Claim 7
Dependent Claim
17 words
An optical recording method according to claim 1, wherein the recording layer is a magneto-optical recording layer.
Claim 8
Dependent Claim
18 words
An optical recording method according to claim 1, wherein the recording layer is a phase change recording layer.
Claim 9
Dependent Claim
17 words
An optical recording method according to claim 1, wherein the recording layer is an ablative recording layer.
Claim 10
Dependent Claim
133 words
An optical recording medium suitable for recording/reading out information by irradiating a laser beam at a wavelength of not more than 500 nm onto a recording layer of the optical recording medium, the laser beam being incident from a disc substrate side of the optical recording medium through an objective lens having numerical aperture of 0.55 to 0.70, said optical recording medium comprising a disc substrate and a recording layer, and having a track pitch of not less than 0.4 μm and less than 0.9 μm, a recording area for information recording on the disc substrate being a fiat area not having a guide groove for each track, and the disc substrate having an in-plane birefringence of not more than 20×10 -6 and a vertical birefringence of not more than 300×10 -6 .
Claim 11
Dependent Claim
133 words
An optical recording medium suitable for recording/reading out information by irradiating a laser beam at a wavelength of not more than 500 nm onto a recording layer of the optical recording medium, the laser beam being incident from a disc substrate side of the optical recording medium through an objective lens having numerical aperture of 0.55 to 0.70, said optical recording medium comprising a disc substrate and a recording layer, and having a track pitch of not less than 0.4 μm and less than 0.9 μm, a recording area for information recording on the disc substrate being a fiat area not having a guide groove for each track, and the disc substrate having an in-plane birefringence of not more than 20×10 -6 and a vertical birefringence of not more than 300×10 -6 .
Claim 12
Dependent Claim
16 words
An optical recording medium according to claim 9, wherein the disc substrate is a plastic substrate.
Claim 13
Dependent Claim
16 words
An optical recording medium according to claim 9, wherein the disc substrate has pits for tracking.
Claim 14
Dependent Claim
23 words
An optical recording medium according to claim 9, wherein a non-reflective coating layer is disposed on a laser-incident surface of the disc substrate.
Claim 15
Dependent Claim
17 words
An optical recording medium according to claim 9, wherein the recording layer is a magneto-optical recording layer.
Claim 16
Dependent Claim
18 words
An optical recording medium according to claim 9, wherein the recording layer is a phase change recording layer.
Claim 17
Dependent Claim
17 words
An optical recording medium according to claim 9, wherein the recording layer is an ablative recording layer.
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) | 1999-01-01 | 1999-07-03 | 2000-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-01 | 2003-07-03 | 2004-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-01 | 2007-07-03 | 2008-01-02 | $7700.00 | Window Closed / Lapsed |