US4170032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head and method for preparing the same
Assignee: Panasonic Holdings Corp
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Filing: 1978-09-18
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Granted: 1979-10-02
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Expires: 1998-09-18
Abstract
Abstract A magnetic head having a sputter-deposited glass film of the gap forming area of the magnetic core, said glass film being made of borosilicate glass having the composition consisting of 65-85 mol % of SiO 2 , 8-30 mol % of B 2 O 3 and containing 2-15 mol % of alkali metal oxide Na 2 O and K 2 O and 0.1-5 mol % of Al 2 O 3 , with the molar ratio of boron oxide to alkali metal oxides being defined by the following formula: ##EQU1## The magnetic head provides sharpness of the recording leakage flux, thus giving excellent electromagnetic conversion characteristics.
Inventors
- 👤 Kazuo Yokoyama
- 👤 Ryuji Nishiyama
- 👤 Taketoshi Yonezawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:55
CPC Classifications
C; C04; C04B; C04B37/00; C04B37/003; C04B37/005; G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/235; C04B2237/00; C04B2237/02; C04B2237/04; C04B2237/06; C04B2237/062; C04B2237/10; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/50; C04B2237/70; C04B2237/708; C04B2237/72; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49039
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
91 words
A magnetic head having a sputter-deposited glass film at the gap forming area of the magnetic core, said glass film being made of borosilicate glass having the composition of 65 to 85 mol % SiO 2 and 8 to 30 mol % B 2 O 3 and containing 2 to 15 mol % of alkali metal oxides Na 2 O and K 2 O and 0.1 to 5 mol % of Al 2 O 3 , with the molar ratio of boron oxide to alkali metal oxides being defined by: ##EQU5##
Claim 2
Dependent Claim
91 words
A magnetic head having a sputter-deposited glass film at the gap forming area of the magnetic core, said glass film being made of borosilicate glass having the composition of 65 to 85 mol % SiO 2 and 8 to 30 mol % B 2 O 3 and containing 2 to 15 mol % of alkali metal oxides Na 2 O and K 2 O and 0.1 to 5 mol % of Al 2 O 3 , with the molar ratio of boron oxide to alkali metal oxides being defined by: ##EQU5##
Claim 3
Dependent Claim
36 words
A magnetic head of claim 1, wherein a layer with a composition different from that of said sputter-deposited glass film is interposed between said sputter glass film and the gap forming face of said magnetic core.
Claim 4
Dependent Claim
17 words
A magnetic head of claim 2, wherein said layer of different composition is a SiO 2 layer.
Claim 5
Dependent Claim
16 words
A magnetic head of claim 2, wherein said layer of different composition is a ceramic layer.
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) | 1982-10-01 | 1983-04-02 | 1983-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-01 | 1987-04-02 | 1987-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-01 | 1991-04-02 | 1991-10-02 | $7700.00 | Window Closed / Lapsed |