US5121369A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for direct overwriting information on a magneto-optical recording medium using constant laser beam modulated magnetic field generator
Assignee: International Business Machines Corp
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Filing: 1989-05-25
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Granted: 1992-06-09
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Expires: 2009-05-25
Abstract
Abstract Direct overwriting of encoded data along a track in a magneto-optic recording medium is described. A laser beam, not modulated by data, is directed at the active side of the medium to locally heat the width of one track for conditioning it for direct overwriting. A magnetic head comprising an inductor and a capacitance in parallel with the inductor is movable in an appropriate manner to a selectable track. While the head is in alignment with the beam, current of a preselected polarity is supplied from a current source to the inductor. The current source is disconnected to reverse the field of the magnetic head by reciprocation of energy between the inductor and capacitance. Once the magnetic field is reversed, current is supplied to the inductor for maintaining the field until the next field reversal, the reversal times being determined by the data to be written.
Inventors
- 👤 Tarek Makansi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:35
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10517; G11B11/10519; G11B11/10521; G11B11/10504; G11B11/10508; G11B11/1051; G11B11/10513
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
175 words
A method for direct overwriting of data on an optical data storage medium comprising the steps of: directing a laser beam, non-modulated by data to recorded, at a selectable track on the medium for locally heating the medium to a condition for direct overwriting; providing a magnetic field generator for generating a magnetic field to the medium, the magnetic field generator comprising an inductor and a capacitor arranged in parallel with the inductor; providing current source means for supplying currents of first and second polarities; providing switch means connected to the inductor and the current source means; and controlling the switch means responsive to data to be recorded for supplying the first polarity current from the current source means to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator by a reciprocation of energy between the inductor and the capacitor, and then supplying the second polarity current from the current source means to the inductor.
Claim 2
Independent Claim
175 words
A method for direct overwriting of data on an optical data storage medium comprising the steps of: directing a laser beam, non-modulated by data to recorded, at a selectable track on the medium for locally heating the medium to a condition for direct overwriting; providing a magnetic field generator for generating a magnetic field to the medium, the magnetic field generator comprising an inductor and a capacitor arranged in parallel with the inductor; providing current source means for supplying currents of first and second polarities; providing switch means connected to the inductor and the current source means; and controlling the switch means responsive to data to be recorded for supplying the first polarity current from the current source means to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator by a reciprocation of energy between the inductor and the capacitor, and then supplying the second polarity current from the current source means to the inductor.
Claim 3
Independent Claim
173 words
A method for direct overwriting of data on an optical data storage medium comprising the steps of: directing a laser beam, non-modulated by data to be recorded, at a selectable track on the medium for locally heating the medium to a condition for direct overwriting; providing a magnetic field generator for generating a magnetic field to the medium, the magnetic field generator comprising an inductor and a capacitor arranged in parallel with the inductor; providing a current source for supplying current of a first polarity; providing a switch means connected to the inductor and the current source; and controlling the switch means responsive to data to be recorded for supplying the first polarity current from the current source to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator twice by reciprocation of energy between the inductor and the capacitor, and then supplying the first polarity current from the current source to the inductor.
Claim 4
Independent Claim
173 words
A method for direct overwriting of data on an optical data storage medium comprising the steps of: directing a laser beam, non-modulated by data to be recorded, at a selectable track on the medium for locally heating the medium to a condition for direct overwriting; providing a magnetic field generator for generating a magnetic field to the medium, the magnetic field generator comprising an inductor and a capacitor arranged in parallel with the inductor; providing a current source for supplying current of a first polarity; providing a switch means connected to the inductor and the current source; and controlling the switch means responsive to data to be recorded for supplying the first polarity current from the current source to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator twice by reciprocation of energy between the inductor and the capacitor, and then supplying the first polarity current from the current source to the inductor.
Claim 5
Independent Claim
164 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor and a capacitor arranged in parallel with the inductor; current source means for supplying currents of first and second polarities; switch means connected to the inductor and the current source means for supplying the first polarity current from the current source means to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator by reciprocation of energy between the inductor and the capacitor, and then supplying the second polarity current from the current source means to the inductor, the switching means controlled responsive to the data to be recorded.
Claim 6
Independent Claim
164 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor and a capacitor arranged in parallel with the inductor; current source means for supplying currents of first and second polarities; switch means connected to the inductor and the current source means for supplying the first polarity current from the current source means to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator by reciprocation of energy between the inductor and the capacitor, and then supplying the second polarity current from the current source means to the inductor, the switching means controlled responsive to the data to be recorded.
Claim 7
Dependent Claim
15 words
The apparatus of claim 3, further comprising a voice coil actuator for mounting the inductor.
Claim 8
Dependent Claim
21 words
The apparatus of claim 3, wherein the switch means is comprised of a plurality of transistors and a plurality of diodes.
Claim 9
Independent Claim
163 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor and a capacitor arranged in parallel with the inductor; a current source for supplying current of a first polarity; and switch means connected to the inductor and the current source, the switch means supplying the first polarity current from the current source to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator twice by reciprocation of energy between the inductor and the capacitor, and then supplying the first polarity current from the current source to the inductor, the switch means controlled responsive to data to be recorded.
Claim 10
Independent Claim
163 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor and a capacitor arranged in parallel with the inductor; a current source for supplying current of a first polarity; and switch means connected to the inductor and the current source, the switch means supplying the first polarity current from the current source to the inductor, stopping the flow of the first polarity current to the inductor for a period of time sufficient to reverse the magnetic field of the magnetic field generator twice by reciprocation of energy between the inductor and the capacitor, and then supplying the first polarity current from the current source to the inductor, the switch means controlled responsive to data to be recorded.
Claim 11
Dependent Claim
15 words
The apparatus of claim 6, further comprising a voice coil actuator for mounting the inductor.
Claim 12
Dependent Claim
17 words
The apparatus of claim 6, wherein the switch means is comprised of a transistor and a diode.
Claim 13
Independent Claim
166 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor having an inductance L and a capacitor having a capacitance C connected in parallel with the inductor; current source means for providing currents in first and second directions; current control means connected to the current source means and the inductor, the current control means allowing current to flow from the current source means to the inductor in the first direction, stopping the flow of the first direction current from the current source means to the inductor for approximately π(LC) 1/2 seconds and then allowing current to flow from the current source means to the inductor in the second direction, the current control means operated responsive to data to be recorded.
Claim 14
Independent Claim
166 words
An apparatus for direct overwriting of data on an optical data storage medium comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor having an inductance L and a capacitor having a capacitance C connected in parallel with the inductor; current source means for providing currents in first and second directions; current control means connected to the current source means and the inductor, the current control means allowing current to flow from the current source means to the inductor in the first direction, stopping the flow of the first direction current from the current source means to the inductor for approximately π(LC) 1/2 seconds and then allowing current to flow from the current source means to the inductor in the second direction, the current control means operated responsive to data to be recorded.
Claim 15
Dependent Claim
15 words
The apparatus of claim 9, further comprising a voice coil actuator for mounting the inductor.
Claim 16
Dependent Claim
22 words
The apparatus of claim 9, wherein the current control means is comprised of a plurality of transistors and a plurality of diodes.
Claim 17
Independent Claim
159 words
An apparatus for direct overwriting of data on an optical data storage medium, comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor having an inductance L and a capacitor having a capacitance C connected in parallel with the inductor; a current source for providing current in a first direction; and current control means connected to the current source and the inductor, the current control means allowing current to flow from the current source to the inductor in the first direction, stopping the flow of current from the current source to the inductor for approximately 2π(LC) 1/2 seconds and then allowing current to flow from the current source to the inductor in the first direction, the current control means operated responsive to data to be recorded.
Claim 18
Independent Claim
159 words
An apparatus for direct overwriting of data on an optical data storage medium, comprising: means for directing a laser beam, non-modulated by data, at a selectable track on the medium to locally heat the medium to a condition for direct overwriting; a magnetic field generator for generating a magnetic field to the medium comprising an inductor having an inductance L and a capacitor having a capacitance C connected in parallel with the inductor; a current source for providing current in a first direction; and current control means connected to the current source and the inductor, the current control means allowing current to flow from the current source to the inductor in the first direction, stopping the flow of current from the current source to the inductor for approximately 2π(LC) 1/2 seconds and then allowing current to flow from the current source to the inductor in the first direction, the current control means operated responsive to data to be recorded.
Claim 19
Dependent Claim
15 words
The apparatus of claim 12, further comprising a voice coil actuator for mounting the inductor.
Claim 20
Dependent Claim
18 words
The apparatus of claim 12, wherein the current control means is comprised of a transistor and a diode.
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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) | 1995-06-09 | 1995-12-09 | 1996-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-09 | 1999-12-09 | 2000-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-09 | 2003-12-09 | 2004-06-09 | $7700.00 | Window Closed / Lapsed |