US4438471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head for perpendicular magnetic recording system
Assignee: Fujitsu Ltd
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Filing: 1980-12-05
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Granted: 1984-03-20
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Expires: 2000-12-05
Abstract
Abstract A magnetic head for perpendicular magnetic recording system which assures low write current and high recording reproduction efficiency by using a flat coil and increasing the number of turns of the coil. The flat coil is formed on a substrate and a main pole piece is arranged in the center of the coil and vertically to the surface on which the coil is formed. This magnetic head is suitable particularly for manufacture as a thin film magnetic head.
Inventors
- 👤 Mitsumasa Oshiki
- 👤 Susumu Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:19
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278; G11B5/17
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
158 words
A perpendicular recording magnetic head comprising: (a) a pole substrate member having a first surface forming a transducer face and a second surface opposite thereto, the pole substrate member being formed of first and second non-magnetic substrate portions with corresponding side edges for bonding, and a main pole of a thin ferromagnetic film formed on the side edge of said first substrate portion with the corresponding side edge of the second substrate portion bonded thereto; and (b) a coil substrate member having a coil substrate with a magnetic portion in contact with the main pole thin film and a flat coil formed on the surface of said coil substrate, the pole substrate member being bonded at the second surface thereof to said coil substrate member wherein the main pole thin film in the pole substrate is positioned vertically to the center of the flat coil on the coil substrate to form a single integrated perpendicular recording magnetic head.
Claim 2
Dependent Claim
158 words
A perpendicular recording magnetic head comprising: (a) a pole substrate member having a first surface forming a transducer face and a second surface opposite thereto, the pole substrate member being formed of first and second non-magnetic substrate portions with corresponding side edges for bonding, and a main pole of a thin ferromagnetic film formed on the side edge of said first substrate portion with the corresponding side edge of the second substrate portion bonded thereto; and (b) a coil substrate member having a coil substrate with a magnetic portion in contact with the main pole thin film and a flat coil formed on the surface of said coil substrate, the pole substrate member being bonded at the second surface thereof to said coil substrate member wherein the main pole thin film in the pole substrate is positioned vertically to the center of the flat coil on the coil substrate to form a single integrated perpendicular recording magnetic head.
Claim 3
Dependent Claim
21 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 1, wherein said coil substrate is a ferromagnetic substrate.
Claim 4
Dependent Claim
35 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 1, wherein said coil substrate is a composite substrate having a nonmagnetic substrate and a ferromagnetic thin film formed on the nonmagnetic substrate.
Claim 5
Dependent Claim
50 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 1, wherein a first magnetic core is arranged at the center of said coil on said coil substrate and the magnetic field generated by said coil flows through said at least one magnetic core to said main pole.
Claim 6
Dependent Claim
63 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 4, wherein the coil substrate on which said first magnetic core is arranged is a composite substrate having a nonmagnetic substrate and a ferromagnetic thin film formed on the nonmagnetic substrate and wherein said first magnetic core is arranged on the nonmagnetic substrate on which the ferromagnetic thin film is formed.
Claim 7
Dependent Claim
34 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 4, further comprising a second magnetic core arranged on said pole substrate above said first magnetic core arranged on said coil substrate.
Claim 8
Dependent Claim
29 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 6, wherein the coil substrate on which said first magnetic core is arranged is a ferromagnetic substrate.
Claim 9
Dependent Claim
43 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 6, wherein the coil substrate on which said first magnetic core is arranged is a composite substrate having a nonmagnetic substrate and a ferromagnetic thin film formed on the nonmagnetic substrate.
Claim 10
Dependent Claim
48 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 8, wherein said first magnetic core is arranged on said nonmagnetic substrate of said composite substrate and wherein said coil is formed on said ferromagnetic thin film formed on said nonmagnetic substrate of said composite substrate.
Claim 11
Dependent Claim
32 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 4, wherein the depth from the surface of said main pole to the said flat coil is approximately 50 μm.
Claim 12
Dependent Claim
26 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 10, wherein said magnetic core has a size of approximately 12 μm×100 μm×100 μm.
Claim 13
Dependent Claim
28 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 10 or 11, wherein said main pole piece has a cross-section of approximately 4 μm×70 μm.
Claim 14
Dependent Claim
23 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 1, wherein said main pole has a magnetic flux focusing structure.
Claim 15
Dependent Claim
48 words
The perpendicular recording magnetic head of claim 13, wherein the thickness of the main pole film is wider at the surface of the pole substrate facing the coil substrate than the thickness of the main pole film at the surface of the pole substrate opposite the coil substrate.
Claim 16
Dependent Claim
29 words
A magnetic head for perpendicular magnetic recording systems in accordance with claim 1, further comprising a coil arranged at the end of said main pole for improving reproduction efficiency.
Claim 17
Dependent Claim
25 words
The perpendicular recording magnetic head of claim 1, wherein the thin ferromagnetic film forming the vertical main pole has a thickness of approximately 4 μm.
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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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |