US4251910A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making multitrack magnetic heads
Assignee: Eastman Kodak Co
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Filing: 1979-03-23
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Granted: 1981-02-24
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Expires: 1999-03-23
Abstract
Abstract High track density multitrack magnetic heads are batch-fabricated from a stack of wafers which are photolithographically processed to provide lands and grooves on the wafers. Thin magnetic films are deposited in the grooves; and coils respectively inductively cooperative with the films are photolithographically formed about the films, the lands serving both to provide track-to-track spacing and to protect the magnetic films from magnetostriction-producing stress.
Inventors
- 👤 Neil J. Griffith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:15
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/29; G11B5/295; G11B5/17; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49043; Y10T29/49044; Y10T29/49055; Y10T29/4906; Y10T29/49064
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
In the method of making a multitrack magnetic head, the steps of: (a) forming respective magnetic film means, (b) forming electrically-conductive coil turn segments on each side of repspective film means and connecting said coil turn segments together so as to form at least parts of coils inductively coupled to respective films, (c) grooving a plurality of non-magnetic wafers with generally c-shaped depressions that are at least as deep as the combined thickness of said film and coil turn segments, the forming of said film means and said coil turn segments being in the depressions of at least one of said wafers, (d) bonding said wafers into a stack thereof, and (e) bonding magnetic means to said stack, with a high reluctance gapping material between said stack and said magnetic means, thereby to complete magnetic circuits comprising said magnetic film means, said gapping material and said magnetic means.
Claim 2
Dependent Claim
148 words
In the method of making a multitrack magnetic head, the steps of: (a) forming respective magnetic film means, (b) forming electrically-conductive coil turn segments on each side of repspective film means and connecting said coil turn segments together so as to form at least parts of coils inductively coupled to respective films, (c) grooving a plurality of non-magnetic wafers with generally c-shaped depressions that are at least as deep as the combined thickness of said film and coil turn segments, the forming of said film means and said coil turn segments being in the depressions of at least one of said wafers, (d) bonding said wafers into a stack thereof, and (e) bonding magnetic means to said stack, with a high reluctance gapping material between said stack and said magnetic means, thereby to complete magnetic circuits comprising said magnetic film means, said gapping material and said magnetic means.
Claim 3
Dependent Claim
23 words
In the method of claim 1, the additional step of forming said magnetic film means into alternating films of magnetic and non-magnetic material.
Claim 4
Dependent Claim
41 words
In the method of claim 1, the additional steps of applying non-magnetic films to at least one face of at least some of the wafers in said stack, and covering at least some of said non-magnetic films with respective magnetic films.
Claim 5
Dependent Claim
59 words
In the method of claim 1, the additional steps of forming the magnetic means which is bonded to said stack, said additional steps comprising: (a) grooving a second plurality of non-magnetic wafers with generally c-shaped depressions, (b) placing respective magnetic film means in said depressions, and (c) bonding said second plurality of wafers into a second stack of wafers.
Claim 6
Independent Claim
97 words
The method of making multitrack magnetic heads comprising the steps of: (a) photolithographically forming a plurality of similar discrete depressions on a plurality of non-magnetic wafers, (b) forming magnetic parts within the depressions of said wafers (c) stacking said wafers so that corresponding head parts of respective wafers align with each other, (d) bonding the stack of wafers together, (e) dicing the bonded stack into multitrack subassemblies, (f) lapping the subassemblies to reveal the magnetic head parts within said subassemblies, (g) pairing said subassemblies, and (h) bonding said paired subassemblies together with a non-magnetic gapping material therebetween.
Claim 7
Independent Claim
97 words
The method of making multitrack magnetic heads comprising the steps of: (a) photolithographically forming a plurality of similar discrete depressions on a plurality of non-magnetic wafers, (b) forming magnetic parts within the depressions of said wafers (c) stacking said wafers so that corresponding head parts of respective wafers align with each other, (d) bonding the stack of wafers together, (e) dicing the bonded stack into multitrack subassemblies, (f) lapping the subassemblies to reveal the magnetic head parts within said subassemblies, (g) pairing said subassemblies, and (h) bonding said paired subassemblies together with a non-magnetic gapping material therebetween.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |