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US5144615A
Expired / Lapsed
US
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Apparatus and method for recording and reproducing multi-level information
Assignee: Toshiba Corp
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Filing: 1989-12-22
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Granted: 1992-09-01
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Expires: 2009-12-22
Abstract
Abstract An information recording apparatus includes a record signal analog processor which converts information to be recorded into an analog signal having a plurality of levels, a laser beam source for emitting a laser beam whose energy and radiating time are modulated at multiple levels in accordance with the analog signal, and an optical system for directing the laser beam on an information recording medium. The information recording medium has a recording layer. As a result of the modulation of the laser energy, a plurality of states of recording marks are obtained. As a result of the modulation of the laser radiating time, a plurality of lengths of recording marks are obtained in the radiated portion. Thus, multi-level information is recorded in the data recording medium. The recorded information can be reproduced by detecting the optical characteristics of these recording marks.
Inventors
- 👤 Tadashi Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:33
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/56; G11B; G11B7/00; G11B7/004; G11B7/0055; G11B7/00557; G11C13/00; G11C13/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
137 words
An apparatus for recording and reproducing multi-level information in an information recording medium, wherein said information recording medium comprises an information recording layer from which recorded information can be erased, comprising: signal processing means for converting an information signal to be recorded into a processed signal having one of at least five possible signal levels; light beam output means for outputting a light beam, a combination of whose energy and pulse width duration is modulated at multiple levels in accordance with said signal level; and optical means for directing said light beam onto said information recording medium to form a recording mark, whose state is modulated at multiple levels in accordance with the energy of said light beam and whose length is modulated at multiple levels in accordance with the pulse width duration of said light beam.
Claim 2
Independent Claim
137 words
An apparatus for recording and reproducing multi-level information in an information recording medium, wherein said information recording medium comprises an information recording layer from which recorded information can be erased, comprising: signal processing means for converting an information signal to be recorded into a processed signal having one of at least five possible signal levels; light beam output means for outputting a light beam, a combination of whose energy and pulse width duration is modulated at multiple levels in accordance with said signal level; and optical means for directing said light beam onto said information recording medium to form a recording mark, whose state is modulated at multiple levels in accordance with the energy of said light beam and whose length is modulated at multiple levels in accordance with the pulse width duration of said light beam.
Claim 3
Dependent Claim
34 words
An apparatus according to claim 1, wherein said information recording medium comprises a recording layer in which not less than three states can be obtained in accordance with the energy of the light beam.
Claim 4
Dependent Claim
33 words
An apparatus according to claim 2, wherein said phases of said recording layer of said information recording medium comprise different phases of crystallinity obtained in accordance with the energy of the light beam.
Claim 5
Dependent Claim
42 words
An apparatus according to claim 1, wherein said light beam output means comprises a light source for emitting said light beam, said light source having a frequency which is modulated at multiple levels and whose energy varies in accordance with the frequency.
Claim 6
Dependent Claim
70 words
An apparatus according to claim 1, wherein said light beam output means comprises a light source for emitting a light beam obtained by superimposing a pulse beam whose energy is modulated at multiple levels onto a continuous light beam having constant energy, wherein information previously recorded in said recording layer is erased by the continuous light beam and new information is recorded in said recording layer by said pulse beam.
Claim 7
Dependent Claim
44 words
An apparatus according to claim 1, further comprising information reproducing means for reproducing multi-level information recorded in said information recording medium by detecting a difference in optical characteristics of said recording medium based on not less than three states of said information recording medium.
Claim 8
Independent Claim
122 words
A method for recording and reproducing multi-level information in an information recording medium, wherein said information recording medium comprises an information recording layer from which recorded information can be erased, comprising the steps of: converting information to be recorded into a processed signal having one of at least five possible signal levels; outputting a light beam combination, of whose energy and pulse width duration are modulated at multiple levels in accordance with said signal level; and directing said light beam onto said information recording medium to form a recording mark whose state is modulated at multiple level in accordance with energy or said light beam and whose length is modulated at multiple levels in accordance with pulse duration of said light beam.
Claim 9
Independent Claim
122 words
A method for recording and reproducing multi-level information in an information recording medium, wherein said information recording medium comprises an information recording layer from which recorded information can be erased, comprising the steps of: converting information to be recorded into a processed signal having one of at least five possible signal levels; outputting a light beam combination, of whose energy and pulse width duration are modulated at multiple levels in accordance with said signal level; and directing said light beam onto said information recording medium to form a recording mark whose state is modulated at multiple level in accordance with energy or said light beam and whose length is modulated at multiple levels in accordance with pulse duration of said light beam.
Claim 10
Dependent Claim
34 words
A method according to claim 7, wherein said information recording medium comprises a recording layer in which not less than three phases can be obtained in accordance with radiation energy of the light beam.
Claim 11
Dependent Claim
36 words
A method according to claim 7, wherein said information recording medium comprises a recording layer in which not less than three phases having different crystallinities can be obtained in accordance with the energy of light beam.
Claim 12
Dependent Claim
17 words
A method according to claim 7, wherein said light beam is modulated at multiple wavelengths and energies.
Claim 13
Dependent Claim
42 words
A method according to claim 7, wherein said light beam is formed by superposing a pulse beam whose energy is modulated at multiple levels on a continuous light beam, and new information is recorded in said recording layer by the pulse beam.
Claim 14
Dependent Claim
40 words
A method according to claim 7, further comprising the steps of reproducing the multi-level information recorded in said information recording medium by detecting a difference in optical characteristics based on not less than three states of said information recording medium.
References Cited (Backward Citations)
US4825408A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-01 | 1996-03-02 | 1996-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-01 | 2000-03-02 | 2000-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-01 | 2004-03-02 | 2004-09-01 | $7700.00 | Window Closed / Lapsed |