US3458713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polycarbonate electrets
Assignee: Nortel Networks Ltd
•
Filing: 1966-11-01
•
Granted: 1969-07-29
•
Expires: 1986-11-01
Abstract
No abstract record available.
Inventors
- 👤 Martin Melvin Perlman
- 👤 Cornelis Wilfred Reedyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:49
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/42; H01B3/421; H01B3/426; Y; Y10; Y10S; Y10S55/00; Y10S55/39
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
16 words
AN ELECTRET WHICH COMPRISES A HIGH-MOLECULAR WEIGHT POLYCYCLIC BISPHENOL POLYCARBONATE WHICH HAS BEEN PERMANENTLY ELECTROSTATICALLY POLARIZED.
Claim 2
Dependent Claim
16 words
AN ELECTRET WHICH COMPRISES A HIGH-MOLECULAR WEIGHT POLYCYCLIC BISPHENOL POLYCARBONATE WHICH HAS BEEN PERMANENTLY ELECTROSTATICALLY POLARIZED.
References Cited (Backward Citations)
GB610297A
Cited
US3274156A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-07-28 | 1973-01-27 | 1973-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-07-28 | 1977-01-27 | 1977-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-07-28 | 1981-01-27 | 1981-07-29 | $7700.00 | Window Closed / Lapsed |