Patent US5113300A successfully refreshed from Google Patents.
US5113300A
Expired / Lapsed
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Thin film magnetic head
Assignee: Sony Corp
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Filing: 1991-08-21
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Granted: 1992-05-12
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Expires: 2011-08-21
Abstract
Abstract A thin film magnetic head which includes a substrate of magnetic or nonmagnetic material, an upper magnetic film on the substrate, a coil conductor on the substrate, and a lower magnetic film on the substrate, the lower magnetic film having a groove formed therein for receiving the coil conductor therein. In the preferred form of the present invention, the thickness of the lower magnetic film is at least 0.3 times the thickness of the upper magnetic film when the substrate is composed of a magnetic material and at least 0.8 times the thickness of the upper magnetic film when the substrate is composed of a nonmagnetic material.
Inventors
- 👤 Yoshito Ikeda
- 👤 Hiroaki Narisawa
- 👤 Noboru Wakabayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3109; G11B5/3116
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
159 words
A thin film magnetic head comprising: a substrate of magnetic material, a lower magnetic film physically contacting said substrate, said lower magnetic film having a groove formed therein, a coil conductor disposed within the confines of said groove, the top surface of said coil conductor lying below the top surface of said lower magnetic film, the top surface of said lower magnetic film being flat, said lower magnetic film being made of the same material from the bottom of said lower magnetic film to the top surface of said lower magnetic film, an upper magnetic film overlying said lower magnetic film, the thickness of said lower magnetic film measured at the base of said groove being at least 0.3 times the thickness of said upper magnetic film when said substrate is composed of a magnetic material and being at least 0.8 times the thickness of said upper magnetic material film when said substrate is composed of a nonmagnetic material.
Claim 2
Dependent Claim
159 words
A thin film magnetic head comprising: a substrate of magnetic material, a lower magnetic film physically contacting said substrate, said lower magnetic film having a groove formed therein, a coil conductor disposed within the confines of said groove, the top surface of said coil conductor lying below the top surface of said lower magnetic film, the top surface of said lower magnetic film being flat, said lower magnetic film being made of the same material from the bottom of said lower magnetic film to the top surface of said lower magnetic film, an upper magnetic film overlying said lower magnetic film, the thickness of said lower magnetic film measured at the base of said groove being at least 0.3 times the thickness of said upper magnetic film when said substrate is composed of a magnetic material and being at least 0.8 times the thickness of said upper magnetic material film when said substrate is composed of a nonmagnetic material.
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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) | 1995-05-12 | 1995-11-11 | 1996-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-12 | 1999-11-11 | 2000-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-12 | 2003-11-11 | 2004-05-12 | $7700.00 | Window Closed / Lapsed |