Patent US4743988A successfully refreshed from Google Patents.
US4743988A
Expired / Lapsed
US
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Thin-film magnetic head
Assignee: Victor Company of Japan Ltd
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Filing: 1986-01-28
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Granted: 1988-05-10
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Expires: 2006-01-28
Abstract
Abstract A thin-film magnetic head is disclosed wherein a first core portion includes an insulative island of inorganic material. A first coil section is formed in the island so that it presents a flat common surface with the island and substrate. A gap-forming insulating layer is on the first coil section and the first core portion. A second core portion is on the gap-forming layer, forming a magnetic circuit with the first core portion. A second coil section is connected to the first coil section to form a coil therewith. In a modification, the head comprises a nonmagnetic substrate in which a coil section is formed to present a flat common surface. Metallic ferromagnetic material is used to form core portions on the coil section.
Inventors
- 👤 Kazuhiro Sato
- 👤 Togo Nishiyama
- 👤 Katsuhiko Oguri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3103; G11B5/3163
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A thin-film magnetic head comprising: a first core portion having an insulative island of inorganic material embedded in a base substrate upon which subsequent layers are deposited; a first coil section embedded in said island, the first coil section and the island forming a flat common surface with said substrate; a gap-forming insulating layer on said flat common surface; a second core portion on said gap-forming layer, said second core portion being in magnetically conductive relation with said first core portion; and a second coil section connected to said first coil section to form a coil therewith.
Claim 2
Dependent Claim
97 words
A thin-film magnetic head comprising: a first core portion having an insulative island of inorganic material embedded in a base substrate upon which subsequent layers are deposited; a first coil section embedded in said island, the first coil section and the island forming a flat common surface with said substrate; a gap-forming insulating layer on said flat common surface; a second core portion on said gap-forming layer, said second core portion being in magnetically conductive relation with said first core portion; and a second coil section connected to said first coil section to form a coil therewith.
Claim 3
Dependent Claim
28 words
A thin-film magnetic head as claimed in claim 1, wherein said first core portion comprises a layer of a wear resistive material formed on an insulating nonmagnetic substrate.
Claim 4
Dependent Claim
33 words
A thin-film magnetic head as claimed in claim 2, wherein said layer of a wear resistive material is formed of a metallic ferromagnetic material and said substrate is formed of ceramic or sapphire.
Claim 5
Dependent Claim
35 words
A thin-film magnetic head as claimed in claim 1, wherein said said first core portion comprises a substrate of nonmetallic ferromagnetic material, said substrate having a portion of metallic ferromagnetic material contacting said gap-forming layer.
Claim 6
Dependent Claim
16 words
A thin-film magnetic head as claimed in claim 4, wherein said nonmetallic ferromagnetic material is ferrite.
Claim 7
Dependent Claim
30 words
A thin-film magnetic head as claimed in claim 1, wherein said second coil section is mounted on said second core portion so that said coil surrounds the second core portion.
Claim 8
Dependent Claim
28 words
A thin-film magnetic head as claimed in claim 1, wherein said second coil section is disposed in said substrate so that said coil is in a spiral shape.
Claim 9
Dependent Claim
123 words
A thin-film magnetic head comprising: a base substrate of nonmagnetic material upon which subsequent layers are deposited; a first coil section embedded in said substrate, the first coil section forming a common flat surface with said substrate; a first core portion of metallic ferromagnetic material (54) on said flat surface in electrically nonconductive relation with said first coil section; a second coil section in electrically nonconductive relation with said first core portion and in electrically conductive relation with said first coil section to form a coil therewith; a gap-defining insulating layer on said first core portion; and a second core portion of metallic ferromagnetic material on said gap-defining layer in magnetically conductive relation with said first core portion to form a core therewith.
Claim 10
Dependent Claim
123 words
A thin-film magnetic head comprising: a base substrate of nonmagnetic material upon which subsequent layers are deposited; a first coil section embedded in said substrate, the first coil section forming a common flat surface with said substrate; a first core portion of metallic ferromagnetic material (54) on said flat surface in electrically nonconductive relation with said first coil section; a second coil section in electrically nonconductive relation with said first core portion and in electrically conductive relation with said first coil section to form a coil therewith; a gap-defining insulating layer on said first core portion; and a second core portion of metallic ferromagnetic material on said gap-defining layer in magnetically conductive relation with said first core portion to form a core therewith.
Claim 11
Dependent Claim
18 words
A thin-film magnetic head as claimed in claim 8, wherein said substrate is formed of ceramic or sapphire.
Claim 12
Dependent Claim
32 words
A thin-film magnetic head as claimed in claim 8, wherein said second core portion has a portion overlying said second coil section spaced from said first core portion by an insulative layer.
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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) | 1991-05-10 | 1991-11-09 | 1992-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-10 | 1995-11-09 | 1996-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-10 | 1999-11-09 | 2000-05-10 | $7700.00 | Window Closed / Lapsed |