← Back to Patent Explorer
US4755898A Expired / Lapsed US ⏱️ 0.0 years remaining

Amorphous magnetic head

Assignee: Panasonic Holdings Corp
•
Filing: 1984-06-12
•
Granted: 1988-07-05
•
Expires: 2004-06-12
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A pair of half core pieces is bonded by a high lead glass bond having a low melting point, which is formed on a metal layer of small wetting angle, such as Cr, Cu, Ag, Ti, the metal layer being formed by spattering at least on a part adjacent to a plane of gap of each core piece.

Inventors

  • 👤 Masaru Higashionji
  • 👤 Akio Kuroe
  • 👤 Eisuke Sawai
  • 👤 Mitsuo Satomi
  • 👤 Hiroshi Sakakima
  • 👤 Kenji Kondo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 04:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/235; G11B5/147; G11B5/1475

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 364 words
A magnetic head, comprising: two core pieces, each comprising a laminated block having a ferromagnetic core layer sandwiched between a first non-magnetic substrate layer and second non-magnetic substrate layer: said two core pieces having respective confronting edge surfaces at which corresponding ones of said layers confront one another, block to block; a corresponding portion of each of said confronting edge surfaces constituting a respective gap-forming surface, a magnetic gap being defined between said gap-forming surfaces; means defining a recess for a coil winding in at least one of said core pieces, each said recess defining means being contiguous with said gap-forming surface of the respective said core piece; a gap spacer means provided in said gap on at least one of said gap-forming surfaces; at least one groove formed in said first non-magnetic substrate layer in the confronting edge surface of a respective said block, at least part of such groove being formed in the corresponding gap-forming surface; at least another groove formed in said second non-magnetic substrate layer in the confronting edge surface of a respective said block, at least part of such groove being formed in the corresponding gap-forming surface; each said grooves being defined by a respective inner wall surface; a metal layer formed on said wall surface of each said grooves; said core pieces being bonded together by a filling of adherent glass in said grooves, said glass in each said grooves adhering both to a respective said metal layer in such groove in a respective one of said blocks and to bonding means provided on the corresponding non-magnetic substrate layer on the corresponding other of said blocks; each said ferromagnetic core layers comprising at least one layer of amorphous ferromagnetic material; and said adherent glass filling said grooves being a lead-containing glass having a melting point which is lower than the temperature of crystallization of said amorphous ferromagnetic material; said gap spacer means comprising: two first layers of high melting-point glass, one adhering to each said gap-forming surfaces; and a second layer of lower melting-point glass sandwiched between said two first layers of high melting-point glass and adhering to both of said two first layers of high melting-point glass.
Claim 2
Dependent Claim 364 words
A magnetic head, comprising: two core pieces, each comprising a laminated block having a ferromagnetic core layer sandwiched between a first non-magnetic substrate layer and second non-magnetic substrate layer: said two core pieces having respective confronting edge surfaces at which corresponding ones of said layers confront one another, block to block; a corresponding portion of each of said confronting edge surfaces constituting a respective gap-forming surface, a magnetic gap being defined between said gap-forming surfaces; means defining a recess for a coil winding in at least one of said core pieces, each said recess defining means being contiguous with said gap-forming surface of the respective said core piece; a gap spacer means provided in said gap on at least one of said gap-forming surfaces; at least one groove formed in said first non-magnetic substrate layer in the confronting edge surface of a respective said block, at least part of such groove being formed in the corresponding gap-forming surface; at least another groove formed in said second non-magnetic substrate layer in the confronting edge surface of a respective said block, at least part of such groove being formed in the corresponding gap-forming surface; each said grooves being defined by a respective inner wall surface; a metal layer formed on said wall surface of each said grooves; said core pieces being bonded together by a filling of adherent glass in said grooves, said glass in each said grooves adhering both to a respective said metal layer in such groove in a respective one of said blocks and to bonding means provided on the corresponding non-magnetic substrate layer on the corresponding other of said blocks; each said ferromagnetic core layers comprising at least one layer of amorphous ferromagnetic material; and said adherent glass filling said grooves being a lead-containing glass having a melting point which is lower than the temperature of crystallization of said amorphous ferromagnetic material; said gap spacer means comprising: two first layers of high melting-point glass, one adhering to each said gap-forming surfaces; and a second layer of lower melting-point glass sandwiched between said two first layers of high melting-point glass and adhering to both of said two first layers of high melting-point glass.
Claim 3
Dependent Claim 22 words
The magnetic head of claim 1, wherein: said lower melting-point glass has a melting point in the range of 450° C.-500° C.
Claim 4
Dependent Claim 33 words
The magnetic head of claim 2, wherein: said high melting-point glass is SiO 2 and said lower melting-point glass is a lead glass made of not more than 84 percent PbO by weight.
Claim 5
Dependent Claim 49 words
The magnetic head of claim 2, wherein: each said ferromagnetic core layers comprises at least one layer of amorphous ferromagnetic material; and said adherent glass filling said grooves is a lead-containing glass having a melting point which is lower than the temperature of crystallization of said amorphous ferromagnetic material.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-07-05 1992-01-04 1992-07-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-07-05 1996-01-04 1996-07-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-07-05 2000-01-04 2000-07-05 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag