US4907113A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-pole magnetic recording head
Assignee: PHC Corp
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Filing: 1987-07-29
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Granted: 1990-03-06
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Expires: 2007-07-29
Abstract
Abstract The head includes a read pole disposed between a pair of write poles spaced apart to form a gap therebetween. The read pole conducts flux to a flux sensor that is located away from the gap. The head can be utilized for both longitudinal and perpendicular recording and the readback function can be carried out by an inductive coil or flux sensing devices such as a Hall sensor or an MR sensor. The recording head achieves high readback resolution, high write field gradients, and the capability for write wide-read narrow. The read pole and write poles are laminated structures.
Inventors
- 👤 Michael Mallary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/37; G11B5/372; G11B5/1278; G11B5/187; G11B5/245; G11B5/31; G11B5/3109; G11B5/312; G11B5/313; G11B5/3143; G11B5/332; G11B2005/0002
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
58 words
Magnetic recording head comprising a read pole disposed between a pair of write poles; and a Hall-type magnetic flux sensor associated with the read pole and spaced away from the pole tips, the read pole adapted to conduct flux from its pole tip to the flux sensor and being isolated from the write poles by respective isolation gaps.
Claim 2
Dependent Claim
58 words
Magnetic recording head comprising a read pole disposed between a pair of write poles; and a Hall-type magnetic flux sensor associated with the read pole and spaced away from the pole tips, the read pole adapted to conduct flux from its pole tip to the flux sensor and being isolated from the write poles by respective isolation gaps.
Claim 3
Dependent Claim
15 words
The magnetic recording head of claim 1 wherein the flux sensor is an inductive coil.
Claim 4
Dependent Claim
43 words
The magnetic recording head of claim 1 further including magnetically saturable side shields adjacent to the three poles, the side shields suppressing adjacent track fringing interference during read operation and saturating during write operation so as to effectively appear not to be present.
Claim 5
Dependent Claim
20 words
The magnetic recording head of claim 3 wherein the saturable side shield has a thickness of approximately 3 micro inches.
Claim 6
Dependent Claim
15 words
The magnetic recording head of claim 1 wherein the read and write poles are laminated.
Claim 7
Dependent Claim
60 words
The magnetic recording head of claim 5 wherein the laminated write poles comprise a first layer of NiFe or NiFeCo, a second layer of Al 2 O 3 , a third layer of NiFe or NiFeCo, a fourth layer of Al 2 O 3 , a fifth seed layer of NiFe or NiFeCo, and a sixth layer of thick NiFeCo.
Claim 8
Dependent Claim
17 words
The magnetic recording head of claim 1 further including write coils surrounding one of the write poles.
Claim 9
Dependent Claim
29 words
The magnetic recording head of claim 1 wherein the read pole comprises a laminate having a non-magnetic layer about 50Å thick disposed between magnetic layers, each about 750Å thick.
Claim 10
Dependent Claim
26 words
The magnetic recording head of claim 8 wherein the read pole comprises a thinner layer of Al 2 O 3 disposed between thicker layers of NiFeCo.
Claim 11
Dependent Claim
19 words
The magnetic recording head of claim 9 wherein the Al 2 O 3 layers is approximately 50 Angstroms thick.
Claim 12
Dependent Claim
14 words
The magnetic recording head of claim 1 wherein the Hall sensor is indium antimonide.
Claim 13
Dependent Claim
75 words
Magnetic recording head comprising a read pole disposed in a gap between a pair of write poles; a magnetic flux sensor spaced away from the gap, the read pole adapted to conduct flux to the flux sensor; and at least one magnetically saturable side shield adjacent to the three poles, the side shields suppressing adjacent track fringing interference during read operation and saturating during write operation so as to effectively appear not to be present.
Claim 14
Dependent Claim
75 words
Magnetic recording head comprising a read pole disposed in a gap between a pair of write poles; a magnetic flux sensor spaced away from the gap, the read pole adapted to conduct flux to the flux sensor; and at least one magnetically saturable side shield adjacent to the three poles, the side shields suppressing adjacent track fringing interference during read operation and saturating during write operation so as to effectively appear not to be present.
Claim 15
Dependent Claim
15 words
The head of claim 12 wherein the side shield is approximately 3 micro inches thick.
Claim 16
Dependent Claim
81 words
A magnetic recording head having a read pole disposed in a gap between a pair of write poles, and a magnetic flux sensor associated with the read pole and spaced away from the read pole tip, the read pole adapted to conduct flux from its tip to the flux sensor, at least one of the write poles being tapered inward toward the read pole as the write pole extends to its tip, the read pole being isolated from the write poles.
Claim 17
Dependent Claim
81 words
A magnetic recording head having a read pole disposed in a gap between a pair of write poles, and a magnetic flux sensor associated with the read pole and spaced away from the read pole tip, the read pole adapted to conduct flux from its tip to the flux sensor, at least one of the write poles being tapered inward toward the read pole as the write pole extends to its tip, the read pole being isolated from the write poles.
Claim 18
Dependent Claim
15 words
The magnetic recording head of claim 14 wherein the flux sensor is a magneto-resistive sensor.
Claim 19
Dependent Claim
15 words
The magnetic recording head of claim 14 wherein the flux sensor is a Hall sensor.
Claim 20
Dependent Claim
15 words
The magnetic recording head of claim 14 wherein the flux sensor is an inductive coil.
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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) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |