US3668671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for reading superimposed magnetic recordings
Assignee: International Business Machines Corp
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Filing: 1969-12-15
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Granted: 1972-06-06
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Expires: 1989-12-15
Abstract
Abstract Superimposed tracks of magnetic recordings are read by use of a magneto-optic transducer. The recordings are on a magnetic tape which is passed in close proximity to a magnetic thin film layer coated to the reflecting side of a prism. The superimposed recordings on the tape are selectively transferred to the magnetic thin film by an external bias field. The bias field may be selectively energized or selectively positioned to enhance the transfer of one of the plurality of magnetic recordings to the magnetic thin film. The magnetic recording whose transfer is enhanced is the only recording which will be read by use of the magneto-optic effect.
Inventors
- 👤 Larry H Everett
- 👤 Jack H Judy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:43
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B11/10547; G11C; G11C13/00; G11C13/04; G11C13/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 words
In a magneto-optic transducer having a substrate transparent to radiant energy and a magnetic thin film coated on one surface of said substrate, selective transferring apparatus for selectively transferring one magnetic recording among a plurality of superimposed magnetic recordings from a magnetic storage medium to the thin film, said apparatus comprising: means for transferring the superimposed magnetic recordings from the storage medium to the film; means for selectively applyinG a bias magnetic field to enhance the transfer of one recording oriented in a predetermined direction whereby one magnetic recording from the plurality of superimposed magnetic recordings is selectively transferred to the film.
Claim 2
Dependent Claim
102 words
In a magneto-optic transducer having a substrate transparent to radiant energy and a magnetic thin film coated on one surface of said substrate, selective transferring apparatus for selectively transferring one magnetic recording among a plurality of superimposed magnetic recordings from a magnetic storage medium to the thin film, said apparatus comprising: means for transferring the superimposed magnetic recordings from the storage medium to the film; means for selectively applyinG a bias magnetic field to enhance the transfer of one recording oriented in a predetermined direction whereby one magnetic recording from the plurality of superimposed magnetic recordings is selectively transferred to the film.
Claim 3
Dependent Claim
79 words
Apparatus of claim 1 wherein said means for selectively applying comprises: a plurality of permanent magnetic field sources, the magnetic field from each source degrading the transfer of a single recording when the source is positioned in a predetermined direction with respect to the recording; means for selectively positioning said sources to degrade the transfer of all but one of the recordings so that one magnetic recording from a plurality of superimposed recordings is selectively transferred to said film.
Claim 4
Dependent Claim
75 words
Apparatus of claim 1 wherein said means for selectively applying comprises: a plurality of magnetic field sources, each source is normally inactive and must be energized to produce a magnetic field, each source is oriented to degrade transfer of a recording oriented in a predetermined direction when energized; means for selectively energizing all but one of said sources so that one magnetic recording from a plurality of superimposed recordings is selectively transferred to said film.
Claim 5
Dependent Claim
115 words
Method for selectively reading one of a plurality of superimposed magnetic recordings from a magnetic storage medium comprising steps of: transferring the magnetic recordings from a magnetic storage medium to a thin film attached to a magneto-optic transducer; generating a plurality of bias magnetic fields, each field being oriented to randomize the transfer of one magnetic recording to the thin film; selectively applying the bias magnetic fields to the thin film so that all recordings, but one, are randomized, and that one recording is thereby enhanced relative to the other superimposed recordings; magneto-optically transducing the magnetic recording transferred to the thin film so that one recording of the plurality of superimposed recordings is read out.
Claim 6
Dependent Claim
115 words
Method for selectively reading one of a plurality of superimposed magnetic recordings from a magnetic storage medium comprising steps of: transferring the magnetic recordings from a magnetic storage medium to a thin film attached to a magneto-optic transducer; generating a plurality of bias magnetic fields, each field being oriented to randomize the transfer of one magnetic recording to the thin film; selectively applying the bias magnetic fields to the thin film so that all recordings, but one, are randomized, and that one recording is thereby enhanced relative to the other superimposed recordings; magneto-optically transducing the magnetic recording transferred to the thin film so that one recording of the plurality of superimposed recordings is read out.
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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |