Patent US2684304A successfully refreshed from Google Patents.
US2684304A
Expired / Lapsed
US
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Optical glass
Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1951-06-12
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Granted: 1954-07-20
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Expires: 1971-06-12
Abstract
No abstract record available.
Inventors
- 👤 Weissenberg Gustav
- 👤 Meinert Norbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:52
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/12; C03C3/16; C03C3/17; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/903
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
32 words
OPTICAL FLINT GLASS CONSISTING ESSENTIALLY OF 80% TO 90% BY WEIGHT OF LEAD PHOSPHATE, 5% TO 10% BY WEIGHT OF PHOSPHORUS PENTOXIDE, AND 3% TO 10% BY WEIGHT OF ACID STRONTIUM PHOSPHATE.
Claim 2
Dependent Claim
32 words
OPTICAL FLINT GLASS CONSISTING ESSENTIALLY OF 80% TO 90% BY WEIGHT OF LEAD PHOSPHATE, 5% TO 10% BY WEIGHT OF PHOSPHORUS PENTOXIDE, AND 3% TO 10% BY WEIGHT OF ACID STRONTIUM PHOSPHATE.
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) | 1957-07-19 | 1958-01-18 | 1958-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-07-19 | 1962-01-18 | 1962-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-07-19 | 1966-01-18 | 1966-07-20 | $7700.00 | Window Closed / Lapsed |