EP0078374A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Thin film inductive transducer for perpendicular magnetic recording
Assignee: International Business Machines Corp
•
Filing: 1982-08-19
•
Granted: —
•
Expires: 2002-08-19
Abstract
Abstract © A thin film inductive transducer comprises three magnetic layers (10, 11, 12) deposited on an air bearing slider substrate (13) for perpendicular recording of magnetic transitions on a movable magnetic medium. Two magnetic closures are provided. One is defined by contact of one outer magnetic layer (12 or 10) with the intermediate magnetic layer (11 or 11') within the area bounded by conductive turns (a-h) of a single layer coil (19 or 19'). The other is defined by contact (10,12 or 10', 12') outboard of the conductive turns (a-h). Magnetic transitions may be read by conventional peak detection techniques because the disclosed transducer has three pole tips (P1, P2, P3), the central one (P2) of which is approximately 3-40% of the thickness of the outer pole tips (P1, P3). To avoid "wrap-around" the pole tips (P1, P2, P3) are progressively less wide as their distance from the substrate (31) increases.
Inventors
- 👤 Robert Edward Jones
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 09:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
A thin film inductive transducer formed on a substrate having an air bearing surface, for perpendicular recording and reading of magnetic transitions on a movable magnetic recording medium, characterised by: three thin film magnetic layers disposed in superposed spaced relation on the substrate, with the second layer intermediate the first and third layers, to define a pair of magnetic transducing gaps in a pole tip region adjacent the air bearing surface; a single layer of conductive turns disposed between said first layer and second layer; said first layer contacting said second layer in an area encircled by the conductive turns for forming a split ring enclosing the portion of said conductive turns between said area and the pole tip region to constitute a first magnetic closure; and said first layer contacting said third layer outboard of the conductive turns for forming another split ring to constitute a second magnetic closure.
Claim 2
Dependent Claim
150 words
A thin film inductive transducer formed on a substrate having an air bearing surface, for perpendicular recording and reading of magnetic transitions on a movable magnetic recording medium, characterised by: three thin film magnetic layers disposed in superposed spaced relation on the substrate, with the second layer intermediate the first and third layers, to define a pair of magnetic transducing gaps in a pole tip region adjacent the air bearing surface; a single layer of conductive turns disposed between said first layer and second layer; said first layer contacting said second layer in an area encircled by the conductive turns for forming a split ring enclosing the portion of said conductive turns between said area and the pole tip region to constitute a first magnetic closure; and said first layer contacting said third layer outboard of the conductive turns for forming another split ring to constitute a second magnetic closure.
Claim 3
Dependent Claim
33 words
A transducer as claimed in claim 1, further characterised by the thickness of the second layer in the pole tip region being less than half of that of the first and third layers.
Claim 4
Dependent Claim
46 words
A transducer as claimed in claim 2, further characterised by the thickness of all three magnetic layers being substantially equal, except in the pole tip region, where the thickness of the second magnetic layer is only about 33-40% of that of the first and third layers.
Claim 5
Dependent Claim
84 words
A transducer as claimed in claim 3, further characterised in that, in the pole tip region, the second layer has a thickness of the order of about 1 micron and the first layer and third layer have thicknesses of the order of about 2.5-3 microns, whereas remote from the pole tip region the three magnetic layers are of substantially equal thickness of the order of about 2.5-3 microns, and the dimension of each transducing gap is of the order of about 0.5 micron. e
Claim 6
Dependent Claim
35 words
A transducer as claimed in any preceding claim, characterised by the widths of the magnetic layers at the pole tip region being progressively less as the distance of the magnetic layers from the substrate increases.
Claim 7
Dependent Claim
18 words
A transducer as claimed in any preceding claim, characterised by said first layer being farthest from the substrate.
Claim 8
Dependent Claim
22 words
A transducer as claimed in any of claims 1 to 5, characterised by said first layer being the closest to the substrate.
Claim 9
Dependent Claim
53 words
A transducer as claimed in any preceding claim, characterised by the distance between each magnetic closure and the air bearing surface being minimised by use of conductive turns of equal thin width separated by a helical gap of constant minimal width, for maximising efficiency during both recording and reading by minimising flux leakage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.