US4939717A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for erasing and recording information using three power levels
Assignee: Panasonic Holdings Corp
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Filing: 1987-10-27
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Granted: 1990-07-03
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Expires: 2007-10-27
Abstract
Abstract In a single beam overwrite method, wherein optical recording medium having thin recording film capable of reversible change of phase by irradiating different level laser lights, etc., the laser light is modulated to have three energy levels, i.e., a recording power level, an erasing power level and a very short time of cooling power level which is provided immediately after the recording power level.
Inventors
- 👤 Eiji Ohno
- 👤 Kenichi Nishiuchi
- 👤 Noboru Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:46
CPC Classifications
C; C08; C08L; C08L7/00; G; G11; G11B; G11B7/00; G11B7/004; G11B7/006
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
118 words
A method for erasing and recording information on an optical recording member of the type wherein a new signal is overwritten on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member, comprising the steps of: modulating a recording laser power to a recording power level (PW); maintaining said laser power at said recording power level (PW) for a time corresponding to data to be recorded; lowering said laser power to a cooling power level (PC) which is lower than said recording power level (PW); and maintaining said laser power at said cooling power level (PC) for a predetermined period, to thereby record information.
Claim 2
Independent Claim
118 words
A method for erasing and recording information on an optical recording member of the type wherein a new signal is overwritten on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member, comprising the steps of: modulating a recording laser power to a recording power level (PW); maintaining said laser power at said recording power level (PW) for a time corresponding to data to be recorded; lowering said laser power to a cooling power level (PC) which is lower than said recording power level (PW); and maintaining said laser power at said cooling power level (PC) for a predetermined period, to thereby record information.
Claim 3
Dependent Claim
37 words
A method as in claim 1, comprising the further step of raising said laser power to an erasing power level (PE), PC<PE<PW, and maintaining said laser power at said erasing level until data is to be recorded.
Claim 4
Dependent Claim
32 words
The method in accordance with claim 2, comprising the further step of erasing and recording said optical recording member by reversibly changing said material between an amorphous phase and a crystal phase.
Claim 5
Dependent Claim
16 words
The method in accordance with claim 2, wherein said cooling power level is a laser-off level.
Claim 6
Dependent Claim
43 words
The method in accordance with claim 2, wherein said predetermined period for laser irradiation with said low power level τ is 0<τ<(lambda)/V where: (lambda) is the wavelength of the laser, and V: relative speed between the laser spot and the optical recording member.
Claim 7
Dependent Claim
85 words
The method in accordance with claim 1, wherein an erasing power level of said laser spot is substantially the same as said recording power level and comprising the further steps of: erasing a previously recorded signal by continuous irradiation of said laser spot with said erasing power and melting the recording film, and recording by decreasing the laser power to a low power level and quenching the end of the melted part obtained by a continuous irradiation of said laser spot with said erasing power.
Claim 8
Dependent Claim
17 words
The method in accordance with claim 6 wherein said low power level is a laser off level.
Claim 9
Independent Claim
203 words
A method for erasing and recording information on an optical recording member having a thin recording film capable of reversibly changing between two optically distinguishable phases A and B, comprising the steps of: overwriting a new signal on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member, said single laser spot having three power levels: (1) a recording power level (PW), (2) an erasing power level (PE) and (3) a cooling power level (PC), which power levels have the relation that power level of said PW>power level of said PE>power level of said PC, to record one signal in the form of said phase A and to record another signal in the form of said phase B: forming said phase A by keeping said power level at said recording power level (PW) for a time corresponding to data to be recorded and then lowering said power level to said low power level (PC) and keeping said power level thereat for a predetermined period; and forming said phase B by keeping said power level at said erasing power level (PE) for another time corresponding to data to be recorded.
Claim 10
Independent Claim
203 words
A method for erasing and recording information on an optical recording member having a thin recording film capable of reversibly changing between two optically distinguishable phases A and B, comprising the steps of: overwriting a new signal on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member, said single laser spot having three power levels: (1) a recording power level (PW), (2) an erasing power level (PE) and (3) a cooling power level (PC), which power levels have the relation that power level of said PW>power level of said PE>power level of said PC, to record one signal in the form of said phase A and to record another signal in the form of said phase B: forming said phase A by keeping said power level at said recording power level (PW) for a time corresponding to data to be recorded and then lowering said power level to said low power level (PC) and keeping said power level thereat for a predetermined period; and forming said phase B by keeping said power level at said erasing power level (PE) for another time corresponding to data to be recorded.
Claim 11
Dependent Claim
33 words
The method in accordance with claim 8, wherein said phase A and phase B are an amorphous phase and crystal phase, and a material of said member is reversibly changeable between said phases.
Claim 12
Dependent Claim
16 words
The method in accordance with claim 8, wherein said low power level is a laser-off level.
Claim 13
Dependent Claim
69 words
The method in accordance with claim 8, wherein erasure of said previously recorded signal is done by continuous irradiation of said laser spot with said erasing power and whereby melting the recording film, and recording is done by decreasing the laser power to said low power level and whereby quenching the end of the melted part obtained by the continuous irradiation of said laser spot with said erasing power.
Claim 14
Dependent Claim
16 words
The method in accordance with claim 11, wherein said lower power level is a laser-off level.
Claim 15
Dependent Claim
42 words
The method in accordance with claim 15, wherein said predetermined period for laser irradiation with said low power level τ is 0<τ<(lambda)/V where (lambda) is the wavelength of the laser V: relative speed between the laser spot and the optical recording member.
Claim 16
Independent Claim
121 words
An apparatus for erasing and recording information on an optical recording member of the type wherein a new signal is overwritten on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member comprising: a variable power laser; means for modulating a recording laser power to a recording power level (PW) and maintaining said laser power at said recording power level (PW) for a time corresponding to data to be recorded, lowering said laser power to a cooling power level (PC) which is lower than said recording power level (PW); and maintaining said laser power at said cooling power level (PC) for a predetermined period to record information.
Claim 17
Independent Claim
121 words
An apparatus for erasing and recording information on an optical recording member of the type wherein a new signal is overwritten on a previously recorded track by means of a single laser spot passing only once on said previously recorded track in said optical recording member comprising: a variable power laser; means for modulating a recording laser power to a recording power level (PW) and maintaining said laser power at said recording power level (PW) for a time corresponding to data to be recorded, lowering said laser power to a cooling power level (PC) which is lower than said recording power level (PW); and maintaining said laser power at said cooling power level (PC) for a predetermined period to record information.
Claim 18
Dependent Claim
39 words
An apparatus as in claim 14, wherein said modulating means includes means for raising said laser power to an erasing power level (PE), PC<PE<PW, and maintaining said laser power at said erasing level until data is to be recorded.
References Cited (Backward Citations)
US4320489A
Cited
JPS56145535A
Cited
JPS56145530A
Cited
US4403318A
Cited
US4472748A
Cited
US4574366A
Cited
US4569881A
Cited
JPS6035303A
Cited
US4639907A
Cited
US4527173A
Cited
US4710911A
Cited
US4679184A
Cited
US4656079A
Cited
DE3601265A1
Cited
US4712207A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |