US4383261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for laser recording utilizing dynamic preheating
Assignee: National Security Agency
•
Filing: 1980-08-21
•
Granted: 1983-05-10
•
Expires: 2000-08-21
Abstract
Abstract An improved method and apparatus for laser recording of information onto a metal film by dynamically heating the film immediately prior to recording. A single track of information is recorded by directing two laser beams onto the film. An unmodulated preheat beam supplies energy to raise the temperature of the metal film to just below that required for recording. A modulated write beam then provides sufficient additional energy to selectively raise the temperature of the film to a necessary level for recording of data.
Inventors
- 👤 Mark W. Goldberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:41
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0045; G11B7/12; G11B7/125; G11B7/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
86 words
A method of optical recording, comprising: focusing an unmodulated beam onto a spot on a thermally sensitive recording medium to heat the medium at said spot to a temperature below the hole formation threshold of the medium; cofocusing a modulated beam superimposed onto the unmodulated beam to form a spot the diameter of which is larger than the spot formed by said unmodulated beam, and selectively varying the temperature of the medium a said smaller spot above and below the hole formation threshold of the medium.
Claim 2
Independent Claim
86 words
A method of optical recording, comprising: focusing an unmodulated beam onto a spot on a thermally sensitive recording medium to heat the medium at said spot to a temperature below the hole formation threshold of the medium; cofocusing a modulated beam superimposed onto the unmodulated beam to form a spot the diameter of which is larger than the spot formed by said unmodulated beam, and selectively varying the temperature of the medium a said smaller spot above and below the hole formation threshold of the medium.
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein said unmodulated beam has a first wavelength and said modulated beam has a second wavelength longer than said first wavelength.
Claim 4
Independent Claim
99 words
A method of optical recording, comprising: focusing each of a plurality of unmodulated beams onto a separate spot on a thermally sensitive recording medium to heat the medium at each spot to a temperature below the hole formation threshold of the medium; cofocusing a plurality of modulated beams, one modulated beam superimposed onto each unmodulated beam to form a plurality of second spots the diameters of which are larger than the spots formed by said unmodulated beams, and selectively varying the temperature of the medium at said smaller spots above and below the hole formation threshold of the medium.
Claim 5
Independent Claim
99 words
A method of optical recording, comprising: focusing each of a plurality of unmodulated beams onto a separate spot on a thermally sensitive recording medium to heat the medium at each spot to a temperature below the hole formation threshold of the medium; cofocusing a plurality of modulated beams, one modulated beam superimposed onto each unmodulated beam to form a plurality of second spots the diameters of which are larger than the spots formed by said unmodulated beams, and selectively varying the temperature of the medium at said smaller spots above and below the hole formation threshold of the medium.
Claim 6
Dependent Claim
30 words
The method of claim 3, wherein each of said unmodulated beams has a first wavelength and each of said modulated beams has a second wavelength longer than said first wavelength.
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) | 1986-05-09 | 1986-11-08 | 1987-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-09 | 1990-11-08 | 1991-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-09 | 1994-11-08 | 1995-05-10 | $7700.00 | Window Closed / Lapsed |