Patent US1871491A successfully refreshed from Google Patents.
Patent US4815197A successfully refreshed from Google Patents.
US4815197A
Expired / Lapsed
US
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Process for producing magnetic head
Assignee: Pioneer Corp
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Filing: 1988-04-15
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Granted: 1989-03-28
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Expires: 2008-04-15
Abstract
Abstract A process for producing a magnetic head having a precisely defined recording width but which can be produced using simple process steps. Track width controlling grooves are formed in at least one of two core block halves made of a magnetic material. A thin film of a nommagnetic material, which serves as a gap spacer, is deposited on the bottoms of the track width controlling grooves and portions therebetween. A thin film layer of a metallic magnetic material is formed on the nonmagnetic thin film, and a thin film layer of a metallic magnetic material is formed on the surface of the other core to be brought into abutment against portions between the track width controlling grooves. The two core halves are then joined to form a core block with the thin film of metallic magnetic material on one core block half facing the thin film of metallic magnetic material on the other core block half. The thin films of metallic magnetic material are then etched away from all areas except where they contact each other as a result of the abutment of the two core block halves.
Inventors
- 👤 Hiroyuki Ota
- 👤 Kazuhiko Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1871; G11B5/1872; G11B5/1874; G11B5/1875; G11B5/1877; G11B5/1878; G11B5/23; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49043; Y10T29/49048; Y10T29/49055; Y10T29/49057; Y10T29/49067
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
195 words
A process for producing a magnetic head comprising: forming track width controlling grooves in at least one of two core block halves made of an oxide magnetic material; forming a thin film of a nonmagnetic material, which is to serve as a gap spacer, on bottoms of said track width controlling grooves and on portions between adjacent ones of said grooves; forming at least one layer of a thin film of a metallic magnetic material on said nonmagnetic thin film; forming at least one layer of a thin film of a metallic magnetic material on a surface of the other core block half which is to be brought into abutment against the portions between said track width controlling grooves; joining the two core block halves to form a core block in such a way that the thin film of a metallic magnetic material on one core block half faces the thin film of a metallic magnetic material on the other one block half; and thereafter etching away the thin films of a metallic magnetic material from all areas except where they contact each other as a result of abutment of the two core block halves.
Claim 2
Dependent Claim
195 words
A process for producing a magnetic head comprising: forming track width controlling grooves in at least one of two core block halves made of an oxide magnetic material; forming a thin film of a nonmagnetic material, which is to serve as a gap spacer, on bottoms of said track width controlling grooves and on portions between adjacent ones of said grooves; forming at least one layer of a thin film of a metallic magnetic material on said nonmagnetic thin film; forming at least one layer of a thin film of a metallic magnetic material on a surface of the other core block half which is to be brought into abutment against the portions between said track width controlling grooves; joining the two core block halves to form a core block in such a way that the thin film of a metallic magnetic material on one core block half faces the thin film of a metallic magnetic material on the other one block half; and thereafter etching away the thin films of a metallic magnetic material from all areas except where they contact each other as a result of abutment of the two core block halves.
Claim 3
Dependent Claim
26 words
The process for producing a magnetic head of claim 1, wherein a thickness of said nonmagnetic material is in a range of 0.2 to 0.3 microns.
Claim 4
Dependent Claim
17 words
The process for producing a magnetic head of claim 1, wherein said metallic magnetic material comprises Permalloy.
Claim 5
Dependent Claim
27 words
The process for producing a magnetic head of claim 3, wherein a thickness of said metallic magnetic material is in a range of 1 to 2 microns.
Claim 6
Dependent Claim
36 words
The process for producing a magnetic head of claim 1, wherein said step of joining said two core halves comprises pouring a molten glass material onto surfaces of said two core halves to be joined together.
Claim 7
Dependent Claim
24 words
The process for producing a magnetic head of claim 5, wherein said glass material is a glass material exerting a corrosive action on metals.
Claim 8
Dependent Claim
22 words
The process for producing a magnetic head of claim 5, wherein said molten glass is at a temperature not exceeding 800° C.
Claim 9
Dependent Claim
61 words
The process for producing a magnetic head of claim 1, further comprising the steps of: cutting said core block along lines through said track width controlling grooves to divide said core block into discrete head chips, grinding and polishing said head chips to produce cylindrical surfaces in areas to make sliding contact with a magnetic tape, and lapping said cylindrical surfaces.
Claim 10
Dependent Claim
50 words
The process for producing a magnetic head of claim 1, further comprising the step of forming a film of a metallic magnetic material having a high hardness between said thin film of a nonmagnetic material and said at least one layer of a thin film of a metallic magnetic material.
Claim 11
Dependent Claim
23 words
The process for forming a magnetic head of claim 9, wherein said film of metallic magnetic material having a high hardness comprises Sendust.
Claim 12
Dependent Claim
31 words
The process for forming a magnetic head of claim 10, wherein a thickness of said film of metallic magnetic material having a high hardness is on the order of 2 microns.
Claim 13
Dependent Claim
50 words
The process for forming a magnetic head of claim 1, wherein track width controlling grooves are formed in both said core halves, the track width controlling grooves forming in one of said core halves having a pitch greater than the track width controlling grooves formed in the other core half.
Claim 14
Dependent Claim
62 words
The process for producing a magnetic head of claim 9, further comprising the step of forming a film of a metallic magnetic material having a high hardness on said bottoms of said track width controlling grooves and said portions between adjacent ones of said grooves prior to formation of said thin film of a nonmagnetic material which serves as a gap spacer.
Claim 15
Dependent Claim
38 words
The process for forming a magnetic head of claim 9, wherein said film of metallic magnetic material formed on said bottoms of said track width controlling grooves and said portions between adjacent ones of said grooves comprises Sendust.
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) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |