US3219353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: International Business Machines Corp
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Filing: 1962-11-30
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Granted: 1965-11-23
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Expires: 1982-11-30
Abstract
No abstract record available.
Inventors
- 👤 Peter I Prentky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/73; G11B5/739; G11B5/73911; G11B5/73917; G11B5/73919; H; H01; H01F; H01F10/00; H01F10/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
46 words
A MAGNETIC DATA RECORDING MEDIUM COMPRISING: A NON-MAGNETIC SUBSTRATE; A LAYER OF HIGH COERCIVITY MAGNETIC MATERIAL BONDED TO THE SUBSTRATE; A LAYER OF HIGH COERCIVITY MAGNETIC MATERIAL BONDED TO THE HIGH COERCIVE MATERIAL; AND A LAYER OF LOW COERCIVITY MAGNETIC MATERIAL BONDED TO THE SHIELDING MATERIAL.
Claim 2
Dependent Claim
46 words
A MAGNETIC DATA RECORDING MEDIUM COMPRISING: A NON-MAGNETIC SUBSTRATE; A LAYER OF HIGH COERCIVITY MAGNETIC MATERIAL BONDED TO THE SUBSTRATE; A LAYER OF HIGH COERCIVITY MAGNETIC MATERIAL BONDED TO THE HIGH COERCIVE MATERIAL; AND A LAYER OF LOW COERCIVITY MAGNETIC MATERIAL BONDED TO THE SHIELDING MATERIAL.
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) | 1968-11-22 | 1969-05-24 | 1969-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-11-22 | 1973-05-24 | 1973-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-11-22 | 1977-05-24 | 1977-11-23 | $7700.00 | Window Closed / Lapsed |