Patent US4686147A successfully refreshed from Google Patents.
US4686147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head and method of producing the same
Assignee: Hitachi Ltd
•
Filing: 1986-02-18
•
Granted: 1987-08-11
•
Expires: 2006-02-18
Abstract
Abstract A highly reliable magnetic head which exhibits excellent magnetic characteristics and is free from film defects can be produced by using a silicone-containing polyimide resin as a material for insulation layers to thereby form homogeneous and flat insulation layers. Such a polyimide resin is suitable for other multi-layered stereo-wiring structures.
Inventors
- 👤 Haruhiko Matsuyama
- 👤 Fusaji Shoji
- 👤 Shunichiro Kuwazuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:48
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/11; Y10T428/1193; Y10T428/31504; Y10T428/31652; Y10T428/31663; Y10T428/31721
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
154 words
A magnetic head wherein an insulation layer of said magnetic head is made of a heat-cured product of an end capped polyimide precursor with organic silicone compound that is a precursor represented by the following general formula [I] or [II] or a mixture thereof: ##STR23## wherein R 1 , R 2 and R 3 each stand for an organic radical having 1 to 6 carbon atoms; Ar 2 is at least one radical selected from the group consisting of ##STR24## when Ar 1 is at one radical selected from the group consisting of ##STR25## or Ar 2 is at least one radical selected from the group consisting of ##STR26## when Ar 1 is at least one radical selected from the group consisting of ##STR27## X 1 stands for --SO 2 -- or --CO--; X 2 is ##STR28## m is 0, 1 or 2 and n stands for a positive number of 1 to 100.
Claim 2
Dependent Claim
154 words
A magnetic head wherein an insulation layer of said magnetic head is made of a heat-cured product of an end capped polyimide precursor with organic silicone compound that is a precursor represented by the following general formula [I] or [II] or a mixture thereof: ##STR23## wherein R 1 , R 2 and R 3 each stand for an organic radical having 1 to 6 carbon atoms; Ar 2 is at least one radical selected from the group consisting of ##STR24## when Ar 1 is at one radical selected from the group consisting of ##STR25## or Ar 2 is at least one radical selected from the group consisting of ##STR26## when Ar 1 is at least one radical selected from the group consisting of ##STR27## X 1 stands for --SO 2 -- or --CO--; X 2 is ##STR28## m is 0, 1 or 2 and n stands for a positive number of 1 to 100.
Claim 3
Dependent Claim
30 words
A magnetic head as set forth in claim 1, wherein the end capped polyimide precursor with organic silicone compound is a soluble material having high adhesiveness for a head substrate.
Claim 4
Dependent Claim
68 words
A magnetic head as set forth in claim 1, wherein R 1 is ethyl, propyl or butyl radical; R 2 is methyl, ethoxy, propoxy or butoxy radical; R 3 is propylene or phenylene radical; Ar 2 is ##STR29## when Ar 1 is ##STR30## or Ar 2 is ##STR31## when Ar 1 is ##STR32## m is 0 or 1 and n is a positive number of 10 to 50.
Claim 5
Independent Claim
200 words
A method of producing a magnetic head comprising a first magnetic layer, an insulating gap layer, a first insulation layer, a conductor layer, a second insulation layer, a second magnetic head, and a protective layer which are stacked on a substrate in order, which comprises forming the first and second insulation layers by curing an end capped polyimide precursor with organic silicone compound in vacuum; the end capped polyimide precursor with organic silicone compound being a precursor represented by the following general formulae [I] or [II] or a mixture thereof: ##STR33## wherein R 1 , R 2 and R 3 each stand for an organic radical having 1 to 6 carbon toms; Ar 2 is at least one radical selected from the group consisting of ##STR34## when Ar 1 is at least one radical selected from the group consisting of ##STR35## or Ar 2 is at least one radical selected from the group consisting of ##STR36## when Ar 1 is at least one radical selected from the group consisting of ##STR37## X 1 stands for --SO 2 -- or --CO--; X 2 is ##STR38## m is 0, 1, or 2 and n is a positive number of 1 to 100.
Claim 6
Independent Claim
200 words
A method of producing a magnetic head comprising a first magnetic layer, an insulating gap layer, a first insulation layer, a conductor layer, a second insulation layer, a second magnetic head, and a protective layer which are stacked on a substrate in order, which comprises forming the first and second insulation layers by curing an end capped polyimide precursor with organic silicone compound in vacuum; the end capped polyimide precursor with organic silicone compound being a precursor represented by the following general formulae [I] or [II] or a mixture thereof: ##STR33## wherein R 1 , R 2 and R 3 each stand for an organic radical having 1 to 6 carbon toms; Ar 2 is at least one radical selected from the group consisting of ##STR34## when Ar 1 is at least one radical selected from the group consisting of ##STR35## or Ar 2 is at least one radical selected from the group consisting of ##STR36## when Ar 1 is at least one radical selected from the group consisting of ##STR37## X 1 stands for --SO 2 -- or --CO--; X 2 is ##STR38## m is 0, 1, or 2 and n is a positive number of 1 to 100.
Claim 7
Dependent Claim
34 words
A method of producing a magnetic head as set forth in claim 4, wherein the end capped polyimide precursor with organic silicone compound is a soluble material having a high adhesiveness to the substrate.
Claim 8
Dependent Claim
74 words
A method of producing a magnetic head as set forth in claim 4, wherein R 1 is methyl, ethyl, propyl or butyl radical; R 2 is methyl, methoxy, ethoxy, propoxy or butoxy radical; R 3 is propylene or phenylene radical; Ar 2 is ##STR39## when Ar 1 is ##STR40## or Ar 2 is ##STR41## when Ar 1 is ##STR42## m is 0 or 1 and n is a positive number of 10 to 50.
References Cited (Backward Citations)
US3544982A
Cited
US4589043A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |