US4725909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vertical magnetic head comprising means for converging magnetic flux to enable high density recording
Assignee: Olympus Corp
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Filing: 1987-04-30
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Granted: 1988-02-16
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Expires: 2007-04-30
Abstract
Abstract A vertical magnetic head for recording information on a recording medium and reproducing the recorded information from the recording medium with high density employing a main magnetic pole and auxiliary magnetic pole(s). The head comprises a main magnetic pole and auxiliary magnetic pole(s) attached to the main magnetic pole and spaced apart therefrom in the direction generally perpendicular to the moving direction of the recording medium. The recording/reproduction is carried out under the condition that a plane including said both magnetic poles is perpendicular to the moving direction of the recording medium. Further, the auxiliary pole is tapered in the direction of the main magnet so that the narrowest part of the auxiliary pole is nearest the main magnetic pole.
Inventors
- 👤 Masahiro Kawai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
222 words
A vertical magnetic head comprising: a thin film main magnetic pole having high magnetic permeability, said main magnetic pole has a tip facing the surface of a magnetic recording medium, said thin film main magnetic pole positioned such that the thickness of said thin film is generally in the same direction as the moving direction of the magnetic recording medium; at least one auxiliary magnetic pole having a tip facing said magnetic medium and having a body, said tip formed separate from the tip of the main magnetic pole, the tip of said auxiliary magnetic pole being spaced from said main magnetic pole in a direction generally transverse to the moving direction of the magnetic recording medium and also, said tip of said auxiliary magnetic pole having a substantially larger cross-sectional area than said tip of said main magnetic pole, and wherein the tip of said auxiliary magnetic pole is tapered, in a plan view, in the direction of said main magnetic pole, such that the narrow part of the tapered tip of said auxiliary magnetic pole is nearer said main magnetic pole than the wide part of the tapered tip, and wherein said main magnetic pole and the body of said auxiliary magnetic pole are attached to one another; and a coil winding wound around the body of said auxiliary pole.
Claim 2
Dependent Claim
222 words
A vertical magnetic head comprising: a thin film main magnetic pole having high magnetic permeability, said main magnetic pole has a tip facing the surface of a magnetic recording medium, said thin film main magnetic pole positioned such that the thickness of said thin film is generally in the same direction as the moving direction of the magnetic recording medium; at least one auxiliary magnetic pole having a tip facing said magnetic medium and having a body, said tip formed separate from the tip of the main magnetic pole, the tip of said auxiliary magnetic pole being spaced from said main magnetic pole in a direction generally transverse to the moving direction of the magnetic recording medium and also, said tip of said auxiliary magnetic pole having a substantially larger cross-sectional area than said tip of said main magnetic pole, and wherein the tip of said auxiliary magnetic pole is tapered, in a plan view, in the direction of said main magnetic pole, such that the narrow part of the tapered tip of said auxiliary magnetic pole is nearer said main magnetic pole than the wide part of the tapered tip, and wherein said main magnetic pole and the body of said auxiliary magnetic pole are attached to one another; and a coil winding wound around the body of said auxiliary pole.
Claim 3
Dependent Claim
47 words
The vertical magnetic head of claim 1, wherein a second auxiliary magnetic pole is provided on the opposite side of said main magnetic pole with respect to said one auxiliary magnetic pole, said second auxiliary magnetic pole having the same construction as said one auxiliary magnetic pole.
Claim 4
Dependent Claim
49 words
The vertical magnetic head of claim 1, wherein said main magnetic pole comprises a thin film of high magnetic permeability sandwiched between two thick-walled magnetic members having high magnetic permeability, with non-magnetic members provided to sandwich the tip of said main magnetic pole therebetween rather than said thick-walled members.
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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) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |