US4992897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for reading and writing on a magnetic medium
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
•
Filing: 1989-04-13
•
Granted: 1991-02-12
•
Expires: 2009-04-13
Abstract
Abstract A device for reading and writing of information on a magnetic medium such as a disk or tape comprises at least one reading and writing head placed on a base having a catamaran type profile. The head is composed of a magnetic circuit (a winding on a medium) self-positioned and welded to the walls of a hole made in the base, a flow concentrator in contact with the extremities of the magnetic circuit and a pole piece made up of two magnetic parts separated by a magnetic spacer. The pole piece is positioned opposite to the track of the magnetic medium.
Inventors
- 👤 Patrice Deroux-Dauphin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:36
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/10; G11B5/127; G11B5/31; G11B5/3103; G11B5/3163; G11B5/3176; G11B5/3179; G11B5/3183
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
194 words
A device for reading and writing information on a magnetic medium, comprising at least one magnetic writing and reading head on a monocrystalline silicon base, said base having a catamaran-type profile and having a front face intended to be opposite said magnetic medium and a rear face, the front and rear faces being oriented according to the crystallographical plan 100 of silicon wherein the magnetic reading and writing head comprises: means defining at least one hole in the rear face of the base, said hole having a bottom and walls slanted according to the crystallographical planes 111 of the silicon; a magnetic circuit seated in said hole, said circuit having a pair of spaced-apart extremities between said walls and facing the front face of the base, and a pair of electrical connections; a magnetic flux concentrator in contact with the magnetic circuit extremities; a non-magnetic electrically conductive layer covering said flux concentrator; a masking layer covering said conductive layer except at a selected area thereof; and a writing and reading pole piece contacting said conductive area in said selected area thereof, said pole piece being substantially flush with the front face of the base.
Claim 2
Independent Claim
194 words
A device for reading and writing information on a magnetic medium, comprising at least one magnetic writing and reading head on a monocrystalline silicon base, said base having a catamaran-type profile and having a front face intended to be opposite said magnetic medium and a rear face, the front and rear faces being oriented according to the crystallographical plan 100 of silicon wherein the magnetic reading and writing head comprises: means defining at least one hole in the rear face of the base, said hole having a bottom and walls slanted according to the crystallographical planes 111 of the silicon; a magnetic circuit seated in said hole, said circuit having a pair of spaced-apart extremities between said walls and facing the front face of the base, and a pair of electrical connections; a magnetic flux concentrator in contact with the magnetic circuit extremities; a non-magnetic electrically conductive layer covering said flux concentrator; a masking layer covering said conductive layer except at a selected area thereof; and a writing and reading pole piece contacting said conductive area in said selected area thereof, said pole piece being substantially flush with the front face of the base.
Claim 3
Dependent Claim
30 words
The device according to claim 1 wherein the flux concentrator comprises a layer of magnetic material and a wall of non-magnetic material separating said magnetic material layer into two sections.
Claim 4
Dependent Claim
26 words
The device according to claim 1 wherein the layer of magnetic material is of FeSiAl and the layer of non-magnetic material is of SiO 2 .
Claim 5
Dependent Claim
31 words
The device according to claim 1 wherein the writing and reading pole piece comprises a layer of magnetic material and a non-magnetic spacer separating said magnetic material layer into two sections.
Claim 6
Dependent Claim
28 words
The device according to claim 4 wherein the layer of magnetic material comprising the pole piece is of FeNi and the non-magnetic spacer is of SiO 2 .
Claim 7
Dependent Claim
25 words
The device according to claim 1 and further including an insulating protective layer covering the rear face of the base except around said electrical connections.
Claim 8
Dependent Claim
22 words
The device according to claim 6 wherein said protective layer is selected from the group consisting of aluminum and insulating metal oxides.
Claim 9
Dependent Claim
45 words
The device according to claim 1 and further including means for fixing the magnetic circuit in said hole and for fixing the flux concentrator and pole piece to said base, said fixing means being selected from the group consisting of meltable glass and duroplastic polymers.
Claim 10
Dependent Claim
15 words
The device according to claim 1 wherein the masking layer is of SiO 2 .
Claim 11
Dependent Claim
14 words
The device according to claim 1 wherein the non-magnetic conductive layer is of tungsten.
Claim 12
Dependent Claim
32 words
The device according to claim 1 and further including stop means at the bottom of said hole, said stop means having walls slanted according to the crystallographical planes 111 of the silicon.
Claim 13
Dependent Claim
27 words
The device according to claim 1 and further including connection means at the rear face of said base and connected electrically to said pair of electrical connections.
References Cited (Backward Citations)
GB879600A
Cited
US3672043A
Cited
US3564522A
Cited
US3601871A
Cited
US4698708A
Cited
US4809103A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |