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US4639810A Expired / Lapsed US ⏱️ 0.0 years remaining

Magnetic head for perpendicular magnetization

Assignee: Victor Company of Japan Ltd
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Filing: 1984-02-17
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Granted: 1987-01-27
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Expires: 2004-02-17
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Abstract

Abstract A magnetic head for perpendicular magnetization has a pair of first and second blocks each composed of a nonmagnetic body and a ferromagnetic yoke joined together, a thin ferromagnetic film sandwiched between the first and second blocks, a coil wound around the thin film and the yoke of the first block, and a third ferromagnetic block attached to the first block remotely from the thin film and the second block. In a playback mode, a closed magnetic path is formed through a magnetic recording medium, the thin film, the yoke of the first block, and the third block.

Inventors

  • 👤 Kunihide Sakai

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 08:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 124 words
A magnetic head for perpendicular magnetization, comprising: (a) a body of a nonmagnetic material having a surface for sliding contact with a magnetic recording medium; (b) a yoke of a ferromagnetic material, said body being mounted on said yoke; (c) a film of a ferromagnetic material having a relatively high saturation magnetic density held in direct contact with a side of said yoke and having an end exposed in said surface; (d) a coil wound around said yoke and said film in direct contact with said film; and (e) a block of a ferromagnetic oxide material attached to a side of said body and said yoke for cooperating with the magnetic recording medium, said film, and said yoke in defining a closed magnetic path.
Claim 2
Dependent Claim 124 words
A magnetic head for perpendicular magnetization, comprising: (a) a body of a nonmagnetic material having a surface for sliding contact with a magnetic recording medium; (b) a yoke of a ferromagnetic material, said body being mounted on said yoke; (c) a film of a ferromagnetic material having a relatively high saturation magnetic density held in direct contact with a side of said yoke and having an end exposed in said surface; (d) a coil wound around said yoke and said film in direct contact with said film; and (e) a block of a ferromagnetic oxide material attached to a side of said body and said yoke for cooperating with the magnetic recording medium, said film, and said yoke in defining a closed magnetic path.
Claim 3
Dependent Claim 36 words
A magnetic head as recited in claim 1 wherein said block of ferromagnetic oxide has a coplanar surface with a surface of the body of the nonmagnetic material for sliding contact with the magnetic recording medium.
Claim 4
Dependent Claim 161 words
A magnetic head for perpendicular magnetization, comprising: (a) a pair of first and second blocks each having a body of a nonmagnetic material and a yoke of a ferromagnetic material, said bodies being mounted on said yoke and each body having a surface for sliding contact with a magnetic recording medium; (b) a film of a ferromagnetic material having a relatively high saturation magnetic density sandwiched between said first and second blocks in direct contact with said yoke and having an end exposed in said surface; (c) a coil wound around said first block and said film in direct contact with said film, said second block having a hole through which said coil is wound; and (d) a third block of a ferromagnetic oxide material attached to said first block remotely from said film and from said second block for cooperating with the magnetic recording medium, said film, and said yoke of said first block in defining a closed magnetic path.
Claim 5
Dependent Claim 161 words
A magnetic head for perpendicular magnetization, comprising: (a) a pair of first and second blocks each having a body of a nonmagnetic material and a yoke of a ferromagnetic material, said bodies being mounted on said yoke and each body having a surface for sliding contact with a magnetic recording medium; (b) a film of a ferromagnetic material having a relatively high saturation magnetic density sandwiched between said first and second blocks in direct contact with said yoke and having an end exposed in said surface; (c) a coil wound around said first block and said film in direct contact with said film, said second block having a hole through which said coil is wound; and (d) a third block of a ferromagnetic oxide material attached to said first block remotely from said film and from said second block for cooperating with the magnetic recording medium, said film, and said yoke of said first block in defining a closed magnetic path.
Claim 6
Dependent Claim 17 words
A magnetic head according to claim 3, wherein said film has a thickness of about 3 μm.
Claim 7
Dependent Claim 48 words
A magnetic head according to claim 3, further including a pair of bodies of a nonmagnetic material disposed in said first and second blocks and having ends exposed in said surface of said first and second blocks to limit a track width of said end of said film.
Claim 8
Dependent Claim 27 words
A magnetic head according to claim 5, wherein each of said last-mentioned bodies comprises a semiconical mass of glass having a larger end exposed in said surface.
Claim 9
Dependent Claim 151 words
A magnetic head for perpendicular magnetization, comprising: (a) a pair of first and second blocks each having a body of a nonmagnetic material and a yoke of a ferromagnetic material joined to each other, each said body having a surface for sliding contact with a magnetic recording medium; (b) a film of a ferromagnetic material having a relatively high saturation magnetic density sandwiched between said first and second blocks and having an end exposed in said surface; (c) a coil would around said first block and said film; and (d) a third block of a ferromagnetic material attached to said first block remotely from said film and from said second block for cooperating with the magnetic recording medium, said film, and said yoke of said block in defining a closed magnetic path; said yokes of said first and second blocks having a pair of holes in which said coil is wound.
Claim 10
Dependent Claim 151 words
A magnetic head for perpendicular magnetization, comprising: (a) a pair of first and second blocks each having a body of a nonmagnetic material and a yoke of a ferromagnetic material joined to each other, each said body having a surface for sliding contact with a magnetic recording medium; (b) a film of a ferromagnetic material having a relatively high saturation magnetic density sandwiched between said first and second blocks and having an end exposed in said surface; (c) a coil would around said first block and said film; and (d) a third block of a ferromagnetic material attached to said first block remotely from said film and from said second block for cooperating with the magnetic recording medium, said film, and said yoke of said block in defining a closed magnetic path; said yokes of said first and second blocks having a pair of holes in which said coil is wound.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-01-26 1990-07-28 1991-01-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-01-26 1994-07-28 1995-01-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-01-26 1998-07-28 1999-01-27 $7700.00 Window Closed / Lapsed

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