US4881144A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetic head
Assignee: Hitachi Ltd
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Filing: 1988-01-11
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Granted: 1989-11-14
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Expires: 2008-01-11
Abstract
Abstract In a thin film magnetic head of the type wherein a lower magnetic pole, a gap layer, a first insulating layer, a coil, a second insulating layer and an upper magnetic pole are formed sequentially on a substrate, the present invention provides a thin film magnetic head characterized in that a surface active layer made of aluminum oxide, for example, is disposed between the first insulating layer and the second insulating layer except where the coil is formed on the first insulating layer so that the surface active layer is disposed between the coil and the second insulating layer. According to the present invention, it is possible to prevent the occurrence of bubbles between coil conductors, and eventually to improve flatness of the surface of the second insulating layer and to prevent degradation of the characteristics of the upper magnetic pole.
Inventors
- 👤 Isamu Yuito
- 👤 Eijin Moriwaki
- 👤 Kazuo Shiiki
- 👤 Yoshihiro Hamakawa
- 👤 Hisashi Takano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:14
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3163
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
92 words
In a thin film magnetic head including a lower magnetic pole formed on a substrate, a gap layer, a first, insulating layer, a coil formed on said first insulating layer, a second insulating layer formed on said first insulating layer and on said coil, and an upper magnetic pole, the improvement wherein a surface active layer is formed having opposite sides wherein one side is sequentially contiguous to both said first insulating layer and said coil and the other side of said surface active layer is contiguous to said second insulating layer.
Claim 2
Dependent Claim
92 words
In a thin film magnetic head including a lower magnetic pole formed on a substrate, a gap layer, a first, insulating layer, a coil formed on said first insulating layer, a second insulating layer formed on said first insulating layer and on said coil, and an upper magnetic pole, the improvement wherein a surface active layer is formed having opposite sides wherein one side is sequentially contiguous to both said first insulating layer and said coil and the other side of said surface active layer is contiguous to said second insulating layer.
Claim 3
Dependent Claim
21 words
A thin film magnetic head according to claim 1, wherein said surface active layer is made of an insulating aluminum compound.
Claim 4
Dependent Claim
19 words
A thin film magnetic head according to claim 2, wherein said surface active layer is at least 30 Åthick.
Claim 5
Dependent Claim
19 words
A thin film magnetic head according to claim 1, wherein said surface active layer is made of aluminum oxide.
Claim 6
Dependent Claim
19 words
A thin film magnetic head according to claim 4 wherein said surface active layer is at least 30 Åthick.
Claim 7
Dependent Claim
19 words
A thin film magnetic head according to claim 4 wherein said aluminum oxide is formed by aluminum chelate treatment.
Claim 8
Dependent Claim
17 words
A thin film magnetic head according to claim 4 wherein said aluminum oxide is formed by sputtering.
Claim 9
Dependent Claim
21 words
A thin film magnetic head according to claim 4 wherein said first and second insulating layer are made of polyimide isoindro-quinazolinedione.
Claim 10
Dependent Claim
22 words
A thin film magnetic head according to claim 4 wherein said first and second insulating layers are made of a polymer resin.
Claim 11
Dependent Claim
19 words
A thin film magnetic head according to claim 1 wherein said surface active layer is at least 30 Åthick.
Claim 12
Dependent Claim
21 words
A thin film magnetic head according to claim 1 wherein said first and second insulating layers are made of polyimide isoindro-quinazolinedione.
Claim 13
Dependent Claim
22 words
A thin film magnetic head according to claim 1 wherein said first and second insulating layers are made of a polymer resin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |