US4599718A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for erasing a light recording medium
Assignee: TDK Corp
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Filing: 1985-03-08
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Granted: 1986-07-08
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Expires: 2005-03-08
Abstract
Abstract A method for erasing a light recording medium comprising a thermoplastic resin having a number average molecular weight of 30,000 or less wherein a recording pit is refilled by using a light beam diameter greater than the pit diameter.
Inventors
- 👤 Shiro Nakagawa
- 👤 Akihiko Kuroiwa
- 👤 Kenryo Nanba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:23
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/244; G11B7/245; G11B7/004; G11B7/0055; G11B7/12; G11B7/125; G11B7/246; G11B7/248; G11B7/252; G11B7/253; G11B7/2531; G11B7/258
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
93 words
A method for erasing information recorded on a light recording medium comprising a substrate and a recording layer formed on the substrate wherein the recording layer is composed essentially of a thermoplastic resin having a number average molecular weight of 30,000 or less and a light adsorbing dye or pigment, which method comprises refilling a recording pit in the recording layer by irradiating and heating a region of the recording layer covering the pit and its vicinity with a laser or LED beam having a diameter greater than the diameter of the pit.
Claim 2
Independent Claim
93 words
A method for erasing information recorded on a light recording medium comprising a substrate and a recording layer formed on the substrate wherein the recording layer is composed essentially of a thermoplastic resin having a number average molecular weight of 30,000 or less and a light adsorbing dye or pigment, which method comprises refilling a recording pit in the recording layer by irradiating and heating a region of the recording layer covering the pit and its vicinity with a laser or LED beam having a diameter greater than the diameter of the pit.
Claim 3
Dependent Claim
21 words
The method according to claim 1, wherein the beam has a diameter at least 3 times the diameter of the pit.
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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) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |