US4954920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetic head
Assignee: TDK Corp
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Filing: 1987-11-30
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Granted: 1990-09-04
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Expires: 2007-11-30
Abstract
Abstract A thin film magnetic head has a layer of soft magnetic material formed on a substrate. The layer is formed into two yoke pieces and a magnetic return path, which form a gap at ends of the yoke pieces. The opposite ends of the yoke pieces are joined to the magnetic return path by overlaying magneto-resistive pieces to which an electrical bias is applied.
Inventors
- 👤 Kazuhiko Yamada
- 👤 Takao Maruyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:52
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3916; G11B5/3919; G11B5/3922; G11B5/3925; G11B5/3945; G11B5/3948; G11B5/3958; G11B5/3961; G11B5/3964
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
295 words
A thin film magnetic head for reading recorded information from a magnetic recording medium which is moving in a first direction relative to said thin film magnetic head, said thin film magnetic head comprising: a pair of yokes made of a magnetically permeable film having a predetermined thickness, said pair of yokes being formed on a substrate and covered by a first insulative layer, said thickness of said yokes defining a track width of said thin film magnetic head, a space between first ends of said pair of yokes defining a magnetic gap of said thin film magnetic head, second ends of said pair of yokes being spaced apart from each other, a magnetic anisotropy of said pair of yokes being directed in substantially said first direction; a pair of magneto-resistive elements magnetically connected to said second ends of said pair of yokes, respectively, said pair of magneto-resistive elements being formed on said first insulative layer and covered by a second layer, a return path made of a magnetically permeable film, a coil surrounding said return path for supplying recording current, said return path magnetically connecting said pair of magneto-resistive elements, a magnetic anisotropy of said return path being directed in a second direction which is substantially perpendicular to said first direction, said coil including lower and upper coil patterns, said lower coil pattern being formed on said second insulative layer and covered by a third insulative layer, said return path being formed on said third insulative layer and covered by a fourth insulative layer, said upper coil pattern being formed on said fourth insulative layer, and both ends of said upper coil pattern being connected to both ends of said lower coil pattern at positions where said third and fourth insulative layers are removed.
Claim 2
Dependent Claim
295 words
A thin film magnetic head for reading recorded information from a magnetic recording medium which is moving in a first direction relative to said thin film magnetic head, said thin film magnetic head comprising: a pair of yokes made of a magnetically permeable film having a predetermined thickness, said pair of yokes being formed on a substrate and covered by a first insulative layer, said thickness of said yokes defining a track width of said thin film magnetic head, a space between first ends of said pair of yokes defining a magnetic gap of said thin film magnetic head, second ends of said pair of yokes being spaced apart from each other, a magnetic anisotropy of said pair of yokes being directed in substantially said first direction; a pair of magneto-resistive elements magnetically connected to said second ends of said pair of yokes, respectively, said pair of magneto-resistive elements being formed on said first insulative layer and covered by a second layer, a return path made of a magnetically permeable film, a coil surrounding said return path for supplying recording current, said return path magnetically connecting said pair of magneto-resistive elements, a magnetic anisotropy of said return path being directed in a second direction which is substantially perpendicular to said first direction, said coil including lower and upper coil patterns, said lower coil pattern being formed on said second insulative layer and covered by a third insulative layer, said return path being formed on said third insulative layer and covered by a fourth insulative layer, said upper coil pattern being formed on said fourth insulative layer, and both ends of said upper coil pattern being connected to both ends of said lower coil pattern at positions where said third and fourth insulative layers are removed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |