US3969765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for the thermomagnetic recording of information
Assignee: US Philips Corp
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Filing: 1974-05-20
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Granted: 1976-07-13
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Expires: 1994-05-20
Abstract
Abstract A device for the thermomagnetic recording of information on a highly coercive magnetizable recording medium. For this purpose is used, for example, a video recorder of the "helical scan" or "transversal scan" type whose drum has a co-rotating mirror and system of lenses with which an energy beam is directed and focussed on the recording medium at a small distance in front of the recording gap of the magnetic head. As a result of this the coercive force of the recording medium is locally reduced while using a very short heating time so that the medium can be recorded there by the head.
Inventors
- 👤 Jan Roos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:03
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/48; G11B5/52; G11B5/53; G11B5/86; G11B5/865
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
202 words
A device for recording information on a magnetizable record medium having a temperature-dependent coercive force and being provided on an elongated carrier, comprising means for moving the carrier, at least one magnetic transducer cooperating with the recording medium for producing a magnetic field having a field strength at the area of the recording medium below the coercive force at room temperature thereof, and a heating source to locally heat the recording medium to a temperature above room temperature, the improvement comprising a rotatable cylindrical supporting member around which the record carrier is laid and on the circumference of which the transducer is mounted, the rotatable cylindrical supporting member constituting a means for moving the transducer in a direction which encloses an angle with the direction of movement of the record carrier, wherein the heating source is a source of radiation arranged independently of the supporting member and producing a concentrated energy beam, means mounted on the supporting member for directing the energy beam onto the record carrier and for focussing the energy beam in a location in front of the transducer viewed in the direction of rotation of the supporting member, whereby the energy beam is moved synchronously with the electro-magnetic transducer.
Claim 2
Independent Claim
202 words
A device for recording information on a magnetizable record medium having a temperature-dependent coercive force and being provided on an elongated carrier, comprising means for moving the carrier, at least one magnetic transducer cooperating with the recording medium for producing a magnetic field having a field strength at the area of the recording medium below the coercive force at room temperature thereof, and a heating source to locally heat the recording medium to a temperature above room temperature, the improvement comprising a rotatable cylindrical supporting member around which the record carrier is laid and on the circumference of which the transducer is mounted, the rotatable cylindrical supporting member constituting a means for moving the transducer in a direction which encloses an angle with the direction of movement of the record carrier, wherein the heating source is a source of radiation arranged independently of the supporting member and producing a concentrated energy beam, means mounted on the supporting member for directing the energy beam onto the record carrier and for focussing the energy beam in a location in front of the transducer viewed in the direction of rotation of the supporting member, whereby the energy beam is moved synchronously with the electro-magnetic transducer.
Claim 3
Dependent Claim
15 words
A device as claimed in claim 1, wherein the source of radiation is a laser.
Claim 4
Dependent Claim
45 words
A device as claimed in claim 1, further comprising means for supplying to a detection device part of an energy beam reflected by the record carrier, with which detection device a signal can be generated which controls the energy output of the source of radiation.
Claim 5
Independent Claim
146 words
A device for recording information on a magnetizable recording medium having a temperature-dependent coercive force and being provided on an elongated carrier, comprising a rotatable cylindrical supporting member around which the record carrier is laid in a loop and on the circumference of which the transducer is mounted, the rotatable cylindrical supporting member constituting a means for moving the transducer in a direction which encloses an angle with the direction of movement of the record carrier, wherein the heating source is a source of radiation rigidly mounted on the supporting member and producing a concentrated energy beam, means mounted on the supporting member for directing the energy beam onto the record carrier and for focussing the energy beam on a location in front of the transducer viewed in the direction of rotation of the supporting member, whereby the beam is moved synchronously with the electro-magnetic transducer.
Claim 6
Independent Claim
146 words
A device for recording information on a magnetizable recording medium having a temperature-dependent coercive force and being provided on an elongated carrier, comprising a rotatable cylindrical supporting member around which the record carrier is laid in a loop and on the circumference of which the transducer is mounted, the rotatable cylindrical supporting member constituting a means for moving the transducer in a direction which encloses an angle with the direction of movement of the record carrier, wherein the heating source is a source of radiation rigidly mounted on the supporting member and producing a concentrated energy beam, means mounted on the supporting member for directing the energy beam onto the record carrier and for focussing the energy beam on a location in front of the transducer viewed in the direction of rotation of the supporting member, whereby the beam is moved synchronously with the electro-magnetic transducer.
Claim 7
Dependent Claim
15 words
A device as claimed in claim 4, wherein the source of radiation is a laser.
Claim 8
Dependent Claim
45 words
A device as claimed in claim 4, further comprising means for supplying to a detection device part of an energy beam reflected by the record carrier, with which detection device a signal can be generated which controls the energy output of the source of radiation.
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) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |