Patent US4807076A successfully refreshed from Google Patents.
US4807076A
Expired / Lapsed
US
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Thin film magnetic head for use in vertical magnetic recording
Assignee: Alps Alpine Co Ltd
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Filing: 1987-03-10
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Granted: 1989-02-21
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Expires: 2007-03-10
Abstract
Abstract A thin film magnetic head for use in the vertical magnetic recording having a main magnetic pole for carrying out recording and reproduction on and from a recording medium, and an auxiliary magnetic pole for cooperating with the main magnetic pole to form a closed magnetic circuit wherein the dimension of the auxiliary magnetic pole is made larger than that of the main magnetic pole at its end facing the recording medium and in their tracking direction to enhance reproduction efficiency.
Inventors
- 👤 Keishi Nakashima
- 👤 Naohiro Ishibashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/1278
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
169 words
A thin film magnetic head for use in vertical magnetic recording on a recording medium moving in a horizontal, tracking direction, comprising: a main magnetic pole for recording and reproducing on and from the recording medium which is oriented in a vertical direction to the recording medium, has an end portion of a first thickness dimension in the tracking direction, and is disposed in a vertical position in close proximity of to the recording medium; and an auxiliary magnetic pole for cooperating with said main magnetic pole to form a closed magnetic circuit which is oriented in the vertical direction, has an end portion of a second thickness dimension in the tracking direction, and the end portion is disposed facing the recording medium at a vertical position retracted from the recording medium by a predetermined distance from the position of the end portion of said main magnetic pole; wherein the predetermined distance said end portion of said auxiliary magnetic pole is retracted is in the range of 1-5 μm.
Claim 2
Dependent Claim
169 words
A thin film magnetic head for use in vertical magnetic recording on a recording medium moving in a horizontal, tracking direction, comprising: a main magnetic pole for recording and reproducing on and from the recording medium which is oriented in a vertical direction to the recording medium, has an end portion of a first thickness dimension in the tracking direction, and is disposed in a vertical position in close proximity of to the recording medium; and an auxiliary magnetic pole for cooperating with said main magnetic pole to form a closed magnetic circuit which is oriented in the vertical direction, has an end portion of a second thickness dimension in the tracking direction, and the end portion is disposed facing the recording medium at a vertical position retracted from the recording medium by a predetermined distance from the position of the end portion of said main magnetic pole; wherein the predetermined distance said end portion of said auxiliary magnetic pole is retracted is in the range of 1-5 μm.
Claim 3
Dependent Claim
167 words
A thin film magnetic head for use in vertical magnetic recording on a recording medium moving in a horizontal, tracking direction, comprising: a main magnetic pole for recording and reproducing on and from the recording medium which is oriented in a vertical direction to the recording medium, has an end portion of a first thickness dimension in the tracking direction, and is disposed in a vertical position in close proximity of to the recording medium; and an auxiliary magnetic pole for cooperating with said main magnetic pole to form a closed magnetic circuit which is oriented in the vertical direction, has an end portion of a second thickness dimension in the tracking direction, and the end portion is disposed facing the recording medium by a predetermined distance from the position of the end portion of said main magnetic pole; wherein the first thickness dimension of the auxiliary magnetic pole is larger than two times the second thickness dimension of the main magnetic pole in their tracking direction.
Claim 4
Dependent Claim
167 words
A thin film magnetic head for use in vertical magnetic recording on a recording medium moving in a horizontal, tracking direction, comprising: a main magnetic pole for recording and reproducing on and from the recording medium which is oriented in a vertical direction to the recording medium, has an end portion of a first thickness dimension in the tracking direction, and is disposed in a vertical position in close proximity of to the recording medium; and an auxiliary magnetic pole for cooperating with said main magnetic pole to form a closed magnetic circuit which is oriented in the vertical direction, has an end portion of a second thickness dimension in the tracking direction, and the end portion is disposed facing the recording medium by a predetermined distance from the position of the end portion of said main magnetic pole; wherein the first thickness dimension of the auxiliary magnetic pole is larger than two times the second thickness dimension of the main magnetic pole in their tracking direction.
Claim 5
Dependent Claim
30 words
A thin magnetic head in accordance with claim 2, wherein the predetermined distance said end portion of said auxiliary magnetic pole is retracted is in the range of 1-5 μm.
References Cited (Backward Citations)
US4546398A
Cited
US4575777A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |