US4581663A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buried servo recording system having dual transducers
Assignee: NEC Corp
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Filing: 1983-10-31
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Granted: 1986-04-08
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Expires: 2003-10-31
Abstract
Abstract A magnetic recorder has a pair of first and second transducers arranged in the longitudinal direction of a record track. The magnetic recorder exchanges signals with a magnetic record medium having a servo control signal prerecorded in a lower layer of said medium. A recording circuit is connected to the first transducer for recording a data signal along the record track in an upper layer of the medium. A reading circuit is connected to one of the first and second transducers for reading the recorded data signal. To the second transducer is connected a servo control circuit connected for reading the prerecorded servo control signal and deriving therefrom a position error signal in response to which the position of the transducers is controlled.
Inventors
- 👤 Hideo Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/31; G11B5/3103; G11B5/3109; G11B5/3116; G11B5/48; G11B5/58; G11B5/596; G11B5/59633; G11B5/5965
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
186 words
A magnetic recorder adapted to exchange signals with a magnetic record medium along a record track, said record medium having a servo control signal prerecorded in a lower layer of said medium comprising: a slider adapted to scan said track having a sufficient amount of bottom surface to create an air cushion between it and the surface of the record medium; a pair of first and second thin film magnetic transducers laminated to each other and mounted on said slider so that the pole faces of said transducers are transverse to the longitudinal direction of said track; a recording circuit connected to said first transducer for recording a data signal along said track in an upper layer of said medium; a readback circuit connected to one of said first and second transducers for reading the recorded data signal; a servo control circuit connected to said second transducer for reading said prerecorded servo control signal and deriving therefrom a position error signal; and means for controlling the position of said slider in response to said position error signal so that said transducers are aligned on said track.
Claim 2
Dependent Claim
186 words
A magnetic recorder adapted to exchange signals with a magnetic record medium along a record track, said record medium having a servo control signal prerecorded in a lower layer of said medium comprising: a slider adapted to scan said track having a sufficient amount of bottom surface to create an air cushion between it and the surface of the record medium; a pair of first and second thin film magnetic transducers laminated to each other and mounted on said slider so that the pole faces of said transducers are transverse to the longitudinal direction of said track; a recording circuit connected to said first transducer for recording a data signal along said track in an upper layer of said medium; a readback circuit connected to one of said first and second transducers for reading the recorded data signal; a servo control circuit connected to said second transducer for reading said prerecorded servo control signal and deriving therefrom a position error signal; and means for controlling the position of said slider in response to said position error signal so that said transducers are aligned on said track.
Claim 3
Dependent Claim
51 words
A magnetic recorder as claimed in claim 1, wherein said readback circuit is connected to said first transducer, and wherein said second transducer is offset with respect to said first transducer in a direction away from the surface of said record medium to eliminate higher harmonics of said prerecroded control signal.
Claim 4
Dependent Claim
77 words
A magnetic rocorder as claimed in claim 1, wherein said first and second transducers are of identical construction, wherein each of said first and second transducers comprises a deposited first layer of magnetic material, an insulated coil structure deposited on said first layer, and a second layer of magnetic material deposited on said insulated coil to form a magnetic core with said first layer of magnetic material, said first and second layers forming a magnetic gap therebetween.
Claim 5
Dependent Claim
15 words
A magnetic recorder as claimed in claim 1, wherein said second transducer comprises a magnetoresistor.
Claim 6
Dependent Claim
18 words
A magnetic recorder as claimed in claim 1, wherein said readback circuit is connected to said second transducer.
Claim 7
Dependent Claim
24 words
A magnetic recorder as claimed in claim 1, wherein said lower layer of the record medium has a higher retentivity than said upper layer.
References Cited (Backward Citations)
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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) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |