Patent US5144601A successfully refreshed from Google Patents.
US5144601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optical overwriting methods using erasing pulses, each of which has a higher frequency and narrower width than that of the overwriting pulses
Assignee: Fujitsu Ltd
•
Filing: 1991-02-14
•
Granted: 1992-09-01
•
Expires: 2011-02-14
Abstract
Abstract A method of overwriting information in a magneto-optical memory medium which includes a simultaneous writing and erasing step of continuously irradiating a written information-carrying area of the recording layer of the memory medium with two different pulses from a single laser beam head in accordance with information to be written, regardless of the presence or absence of written information. A variation includes irradiating the written information-carrying area with an erasing pulse from a laser beam head, regardless of the presence or absence of written information, and the then selectively irradiating the information-erased area with a writing pulse from another laser beam head in accordance with information to be written. According to these methods, it becomes possible to carry out a simple and high-speed overwriting with an increased and stabilized bit positioning accuracy.
Inventors
- 👤 Miyozo Maeda
- 👤 Yuji Inouye
- 👤 Yasunobu Hashimoto
- 👤 Ken-ichi Itoh
- 👤 Seiya Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:59
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10517; G11B11/10519; G11B11/10521
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
167 words
A method of overwriting information onto a magneto-optical memory medium comprising the steps of: a) providing a magneto-optical memory medium having a substrate and a magneto-optical recording layer having a perpendicular magnetization direction characteristic coated thereon, the magneto-optical recording medium having information tracks each of which carries previously selectively recorded magnetic domains; b) irradiating pulse light beams in accordance with information to be overwritten from a single optical head onto one information track of the information tracks, a first one of the pulse light beams including a series of pulses having a power sufficient to overwrite recorded magnetic domains and the remaining pulse light beam including a series of pulses having a higher frequency than that of the overwriting pulses and having a power sufficient to erase recorded magnetic domains, each of the erasing pulses having a pulse width narrower than that of the pulse of overwriting pulses; and c) alternately irradiating the overwriting pulses and the erasing pulses onto the track during overwriting and erasing, respectively.
Claim 2
Independent Claim
167 words
A method of overwriting information onto a magneto-optical memory medium comprising the steps of: a) providing a magneto-optical memory medium having a substrate and a magneto-optical recording layer having a perpendicular magnetization direction characteristic coated thereon, the magneto-optical recording medium having information tracks each of which carries previously selectively recorded magnetic domains; b) irradiating pulse light beams in accordance with information to be overwritten from a single optical head onto one information track of the information tracks, a first one of the pulse light beams including a series of pulses having a power sufficient to overwrite recorded magnetic domains and the remaining pulse light beam including a series of pulses having a higher frequency than that of the overwriting pulses and having a power sufficient to erase recorded magnetic domains, each of the erasing pulses having a pulse width narrower than that of the pulse of overwriting pulses; and c) alternately irradiating the overwriting pulses and the erasing pulses onto the track during overwriting and erasing, respectively.
Claim 3
Dependent Claim
34 words
A method according to claim 1, wherein a frequency of said first one of the pulse light beam is 3 times or more higher than a maximum frequency of the remaining pulse light beam.
Claim 4
Dependent Claim
16 words
A method according to claim 1, wherein the information is "0" and "1" binary signal information.
Claim 5
Dependent Claim
35 words
A method according to claim 1, wherein the height of the pulses of the remaining pulse light beam is lower than a height of the pulses of the first one of the pulse light beams.
Claim 6
Dependent Claim
33 words
A method according to claim 1, wherein a height of the pulses of the remaining pulse light beam is the same as the height of the first one of the pulse light beams.
Claim 7
Dependent Claim
21 words
A method according to claim 1, wherein overwriting of information is carried out in the presence of an external magnetic field.
Claim 8
Dependent Claim
14 words
A method according to claim 1, wherein the magneto-optical memory medium is a disk.
Claim 9
Independent Claim
156 words
A method of overwriting information in a magneto-optical memory medium which comprises a substrate and a magneto-optical recording layer having a perpendicular magnetization direction characteristic coated on the substrate and having information tracks each of which carries previously selectively recorded magnetic domains, said method comprising the steps of: a) irradiating the information tracks with pulse light beams from a single optical head in accordance with information to be overwritten, a first one of the pulse light beams having power sufficient to overwrite recorded magnetic domains and the other ones of the pulse light beams including a series of pulses having a higher frequency than that of the overwriting pulses and having a power sufficient to erase recorded magnetic domains, each of the erasing pulses having a pulse width narrower than that of each of the overwriting pulses; and b) alternately irradiating the overwriting pulses and erasing pulses onto the information tracks during overwriting and erasing, respectively.
Claim 10
Independent Claim
156 words
A method of overwriting information in a magneto-optical memory medium which comprises a substrate and a magneto-optical recording layer having a perpendicular magnetization direction characteristic coated on the substrate and having information tracks each of which carries previously selectively recorded magnetic domains, said method comprising the steps of: a) irradiating the information tracks with pulse light beams from a single optical head in accordance with information to be overwritten, a first one of the pulse light beams having power sufficient to overwrite recorded magnetic domains and the other ones of the pulse light beams including a series of pulses having a higher frequency than that of the overwriting pulses and having a power sufficient to erase recorded magnetic domains, each of the erasing pulses having a pulse width narrower than that of each of the overwriting pulses; and b) alternately irradiating the overwriting pulses and erasing pulses onto the information tracks during overwriting and erasing, respectively.
Claim 11
Dependent Claim
22 words
A method according to claim 8, wherein overwriting of the information is carried out in the presence of an external magnetic field.
Claim 12
Dependent Claim
14 words
A method according to claim 8, wherein the magneto-optical memory medium is a disk.
References Cited (Backward Citations)
JPS59113506A
Cited
JPS59113507A
Cited
US4679180A
Cited
US4882718A
Cited
EP0243656A2
Cited
EP0275323B1
Cited
EP0285461A2
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 |