Patent US4636897A successfully refreshed from Google Patents.
US4636897A
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Perpendicular magnetic recording and reproducing thin film head
Assignee: Hitachi Ltd
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Filing: 1983-10-06
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Granted: 1987-01-13
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Expires: 2003-10-06
Abstract
Abstract A perpendicular magnetic recording and reproducing thin film head of a structure excellent in magnetic characteristics and easy of fabrication, wherein a lower magnetic layer disposed on a flat nonmagnetic substrate is used as a main magnetic pole, a first insulator layer is formed on the main magnetic pole, a conductor for a coil and a second insulator layer are disposed on the first insulator layer, and an upper magnetic layer which lies in contact with the lower magnetic layer through the first insulator layer at one end thereof and directly at the other end thereof and which overlies the second insulator layer in a part thereof other than both the ends is disposed and used as an auxiliary magnetic pole.
Inventors
- 👤 Hitoshi Nakamura
- 👤 Kasuo Shiiki
- 👤 Isamu Yuito
- 👤 Yoshihiro Shiroishi
- 👤 Hideo Fujiwara
- 👤 Kiminari Shinagawa
- 👤 Akemi Iijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:54
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
225 words
A perpendicular magnetic recording and reproducing thin film head, comprising: a nonmagnetic substrate as a bottom member, having an upper surface; a lower magnetic layer which is formed on said non-magnetic substrate on the upper surface of the nonmagnetic substrate; a first insulator layer formed on said lower magnetic layer; a coil conductor layer formed on said first insulator layer; a second insulator layer which overlies said first insulator layer and said coil conductor layer so as to bury said coil conductor layer therein; and an upper magnetic layer which is formed on said second insulator layer; which is formed on said first insulator layer at the end facing the recording medium so as to form a magnetic gap between the upper and lower magnetic layers; and which is formed on said lower magnetic layer at the other end, said lower magnetic layer having a thickness smaller than that of the upper magnetic layer, said lower magnetic layer and said upper magnetic layer functioning respectively as a main magnetic pole and an auxiliary magnetic pole of the thin film head; and wherein an angle defined between a surface of said substrate facing to a magnetic recording medium and said upper surface of said substrate is less than 90°, whereby a gap between the magnetic recording medium and the main magnetic pole during operation is reduced.
Claim 2
Dependent Claim
225 words
A perpendicular magnetic recording and reproducing thin film head, comprising: a nonmagnetic substrate as a bottom member, having an upper surface; a lower magnetic layer which is formed on said non-magnetic substrate on the upper surface of the nonmagnetic substrate; a first insulator layer formed on said lower magnetic layer; a coil conductor layer formed on said first insulator layer; a second insulator layer which overlies said first insulator layer and said coil conductor layer so as to bury said coil conductor layer therein; and an upper magnetic layer which is formed on said second insulator layer; which is formed on said first insulator layer at the end facing the recording medium so as to form a magnetic gap between the upper and lower magnetic layers; and which is formed on said lower magnetic layer at the other end, said lower magnetic layer having a thickness smaller than that of the upper magnetic layer, said lower magnetic layer and said upper magnetic layer functioning respectively as a main magnetic pole and an auxiliary magnetic pole of the thin film head; and wherein an angle defined between a surface of said substrate facing to a magnetic recording medium and said upper surface of said substrate is less than 90°, whereby a gap between the magnetic recording medium and the main magnetic pole during operation is reduced.
Claim 3
Dependent Claim
19 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein said angle is 60°-87°.
Claim 4
Dependent Claim
26 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein the nonmagnetic substrate is made of a glass or ceramic material.
Claim 5
Dependent Claim
22 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein said second insulator layer is not flat.
Claim 6
Dependent Claim
38 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein said lower magnetic layer is 0.1 μm to 1 μm thick, and said upper magnetic layer is 5 μm to 40 μm thick.
Claim 7
Dependent Claim
71 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein a part of said lower magnetic layer extending by 2 to 5 μm on the side facing to the magnetic recording medium is 0.1 μm to 1 μm thick, while the remaining part of said lower magnetic layer is 1 μm to 6 μm thick, and said upper magnetic layer is 5 μm to 40 μm.
Claim 8
Dependent Claim
51 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein at least a part of said lower magnetic layer is either of a magnetic alloy which contains Fe and Si as its principal ingredients and an alloy which contains Fe and Ti as its principal ingredients.
Claim 9
Dependent Claim
29 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein at least a part of said upper magnetic layer is an amorphous magnetic alloy.
Claim 10
Dependent Claim
25 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein said second insulator layer is made of an inorganic insulator.
Claim 11
Dependent Claim
25 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 1, wherein said second insulator layer is made of an organic insulator.
Claim 12
Dependent Claim
23 words
A perpendicular magnetic recording and reproducing thin film head as defined in claim 10, wherein said organic insulator is a polyimide type resin.
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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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |