Patent US4901177A successfully refreshed from Google Patents.
US4901177A
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US
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Magnetic read head for a very narrow track
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1988-03-14
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Granted: 1990-02-13
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Expires: 2008-03-14
Abstract
Abstract Magnetic read head for very narrow track and production process. On a silicon substrate (10) is formed a magnetic circuit (P1, P2, P3), whose thickness is equal to the width of the track to be read. This magnetic circuit is interrupted by a magnetic spacer (20) and two slots (F1, F2), in which are inserted elements sensitive to the magnetic field, e.g. magnetoresistors. The latter are connected to an integrated circuit (12) in the silicon substrate. Application to the reading of information recorded on a magnetic track.
Inventors
- 👤 Jean-Pierre Lazzari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:51
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3945; G11B5/3948; G11B5/332
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
149 words
A magnetic read head comprising: a semiconductor substrate having an upper face; a spacer formed by a magnetic vertical wall perpendicular to said upper face, said spacer having a height at least equal to the width of a track to be read; a loop-like magnetic circuit formed by a magnetic coating, said circuit having two pole pieces separated by said spacer, said magnetic circuit being interrupted by two slots arranged symmetrically with respect to a plane passing through said spacer; two elements having an electric property sensitive to a magnetic field, said two elements being inserted in said slots, an electronic circuit integrated in said semiconductor substrate, said circuit having at least one regulated current generator (G) and a differential amplifier (A) with two inputs respectively connected to the two elements sensitive to the magnetic field and connected in opposition, said amplifier having an output supplying a reading signal.
Claim 2
Dependent Claim
149 words
A magnetic read head comprising: a semiconductor substrate having an upper face; a spacer formed by a magnetic vertical wall perpendicular to said upper face, said spacer having a height at least equal to the width of a track to be read; a loop-like magnetic circuit formed by a magnetic coating, said circuit having two pole pieces separated by said spacer, said magnetic circuit being interrupted by two slots arranged symmetrically with respect to a plane passing through said spacer; two elements having an electric property sensitive to a magnetic field, said two elements being inserted in said slots, an electronic circuit integrated in said semiconductor substrate, said circuit having at least one regulated current generator (G) and a differential amplifier (A) with two inputs respectively connected to the two elements sensitive to the magnetic field and connected in opposition, said amplifier having an output supplying a reading signal.
Claim 3
Dependent Claim
63 words
A read head according to claim 1, wherein the elements (M1, M2) having an electrical property sensitive to the magnetic field are magnetoresistors, said magnetoresistors being connected in opposition to the inputs of the differential amplifier (A), the two magnetoresistors (M1, M2) being polarized in such a way that their resistance varies in opposite directions for the magnetic flux variation which they undergo.
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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) | 1993-02-12 | 1993-08-14 | 1994-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-12 | 1997-08-14 | 1998-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-12 | 2001-08-14 | 2002-02-13 | $7700.00 | Window Closed / Lapsed |