US4803338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head having improved track width narrowing grooves
Assignee: Hitachi Ltd
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Filing: 1987-01-06
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Granted: 1989-02-07
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Expires: 2007-01-06
Abstract
Abstract In a magnetic head employing a metallic ferromagnetic material for portions defining a transducing gap, an oxide film or carbide film and a nonmagnetic metal film are provided in this order on each of track width narrowing grooves, and glass is packed on the nonmagnetic metal film, thereby preventing the deteriorations of magnetic characteristics ascribable to the reaction between the metallic ferromagnetic material and the glass and the production of bubbles ascribable to the reaction between the protective films and the glass, and to achieve the enhancements of recording and reproducing characteristics, the prevention of damages to a recording medium surface, the increase of a head lifetime and the rise of the available percentage of manufacture of the heads. When a glass film is further provided on the nonmagnetic metal film and the glass is packed thereon, more excellent effects are achieved.
Inventors
- 👤 Noriyuki Kumasaka
- 👤 Shigekazu Otomo
- 👤 Takeo Yamashita
- 👤 Hideo Zama
- 👤 Juichi Morikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:51
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/147; G11B5/187; G11B5/21
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
81 words
In a magnetic head having a metallic ferromagnetic material at a portion of said magnetic head which defines a transducing gap, and having track width narrowing grooves filled with a first glass over said metallic ferromagnetic material; a magnetic head characterized in that an oxide film or carbide film is provided on said metallic ferromagnetic material, a nonmagnetic metal film is provided on said oxide film or said carbide film, and said first glass is packed on said nonmagnetic metal film.
Claim 2
Dependent Claim
81 words
In a magnetic head having a metallic ferromagnetic material at a portion of said magnetic head which defines a transducing gap, and having track width narrowing grooves filled with a first glass over said metallic ferromagnetic material; a magnetic head characterized in that an oxide film or carbide film is provided on said metallic ferromagnetic material, a nonmagnetic metal film is provided on said oxide film or said carbide film, and said first glass is packed on said nonmagnetic metal film.
Claim 3
Dependent Claim
29 words
A magnetic head as defined in claim 1, wherein a glass film made of a second glass is further provided between said nonmagnetic metal film and said first glass.
Claim 4
Dependent Claim
85 words
A magnetic head as defined in claim 1, wherein said metallic ferromagnetic material is formed by a ferromagnetic alloy film, said oxide film or carbide film is made of at least one substance selected from the group consisting of SiO 2 , Al 2 O 3 , ZrO 2 , TiC and SiC, and said nonmagnetic metal film is made of at least one element selected from the group consisting of Cr, Ti, Mo, Al, Ge and Si or any of alloys based on them.
Claim 5
Dependent Claim
163 words
A magnetic head comprising: two core halves, each of said core halves having an upper surface, a side surface and a slanted surface slanted at a predetermined angle between said upper surface and said side surface, a metallic ferromagnetic film provided on said upper surface and said slanted surface, a first protective film made of an oxide or carbide provided on said metallic ferromagnetic film over said slanted surface, and a second protective film made of a nonmagnetic metal provided on said first protective film, said core halves being joined with the metallic ferromagnetic films on each of said core halves facing one another and being separated by a transducing gap; and a glass provided between the second protective layers of each of said core halves for joining said core halves, the slanted surfaces of said core halves defining at least one track width narrowing groove, and the first and second protective films preventing reaction between said metallic ferromagnetic layer and said glass.
Claim 6
Dependent Claim
163 words
A magnetic head comprising: two core halves, each of said core halves having an upper surface, a side surface and a slanted surface slanted at a predetermined angle between said upper surface and said side surface, a metallic ferromagnetic film provided on said upper surface and said slanted surface, a first protective film made of an oxide or carbide provided on said metallic ferromagnetic film over said slanted surface, and a second protective film made of a nonmagnetic metal provided on said first protective film, said core halves being joined with the metallic ferromagnetic films on each of said core halves facing one another and being separated by a transducing gap; and a glass provided between the second protective layers of each of said core halves for joining said core halves, the slanted surfaces of said core halves defining at least one track width narrowing groove, and the first and second protective films preventing reaction between said metallic ferromagnetic layer and said glass.
Claim 7
Dependent Claim
29 words
A magnetic head according to claim 4, wherein at least one of said core halves has a recess in said upper surface in which a coil winding is provided.
Claim 8
Dependent Claim
29 words
A magnetic head according to claim 4, further comprising a sputtered glass film between said second protective film of at least one of said core halves and said glass.
Claim 9
Dependent Claim
19 words
A magnetic head according to claim 6, wherein said sputtered glass film has a thickness of 0.1 μm-1.0 μm.
Claim 10
Dependent Claim
37 words
A magnetic head according to claim 4, wherein said metallic ferromagnetic film is made of a material selected from the group consisting of an amorphous ferromagnetic alloy, an Fe-Al-Si system alloy, an Ni-Fe alloy and iron nitride.
Claim 11
Dependent Claim
17 words
A magnetic head according to claim 4, wherein said first protective film is made of an oxide.
Claim 12
Dependent Claim
30 words
A magnetic head according to claim 9, wherein said oxide is a material selected from the group consisting of SiO 2 , Al 2 O 3 and ZrO 2 .
Claim 13
Dependent Claim
17 words
A magnetic head according to claim 4, wherein said first protective film is made of a carbide.
Claim 14
Dependent Claim
25 words
A magnetic head according to claim 11, wherein said carbide is a material selected from the group consisting of TiC, SiC and B 4 C.
Claim 15
Dependent Claim
55 words
A magnetic head according to claim 4, wherein said nonmagnetic metal is made of at least one element selected from the group consisting of Cr, Ti, Mo, Al, Cu, Si and Ge or is made of an alloy whose base is selected from the group consisting of Cr, Ti, Mo, Al, Cu, Si and Ge.
Claim 16
Dependent Claim
21 words
A magnetic head according to claim 4, wherein each of said core halves is made of a high permeability ferromagnetic material.
Claim 17
Dependent Claim
19 words
A magnetic head according to claim 4, wherein each of said core halves is made of a nonmagnetic material.
Claim 18
Dependent Claim
20 words
A magnetic head according to claim 4, wherein the first protective films each have a thickness of 0.2 μm-3.0 μm.
Claim 19
Dependent Claim
20 words
A magnetic head according to claim 4, wherein the second protective films each have a thickness of 0.1 μm-2.0 μm.
Claim 20
Dependent Claim
21 words
A magnetic head according to claim 4, wherein said glass has a melting point in the range of 450° C.-530° C.
Claim 21
Dependent Claim
15 words
A magnetic head according to claim 18, wherein said glass contains 75-85% by weight PbO.
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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) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |