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Patent US2996391A successfully refreshed from Google Patents.
US2996391A
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Optical glass
Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1954-06-30
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Granted: 1961-08-15
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Expires: 1974-06-30
Abstract
No abstract record available.
Inventors
- 👤 Weissenberg Gustav
- 👤 Meinert Norbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:47
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/12; C03C3/16; C03C3/19; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/902; Y10S501/903
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
60 words
OPTICAL CROWN GLASS CONSISTING ESSENTIALLY OF A VITRIFIED MIXTURE OF AT LEAST ONE METAPHOSPHATE OF AN ELEMENT OF THE GROUP CONSISTING OF MAGNESIUM, CALCIUM, STRONTIUM AND BARIUM FROM 20 TO 55 PERCENT BY WEIGHT AND OF AT LEAST ONE ORTHOPHOSPHATE OF AN ELEMENT OF THE GROUP CONSISTING OF MAGNESIUM, CALCIUM, STRONTIUM AND BARIUM FROM 45 TO 80 PERCENT BY WEIGHT.
Claim 2
Dependent Claim
60 words
OPTICAL CROWN GLASS CONSISTING ESSENTIALLY OF A VITRIFIED MIXTURE OF AT LEAST ONE METAPHOSPHATE OF AN ELEMENT OF THE GROUP CONSISTING OF MAGNESIUM, CALCIUM, STRONTIUM AND BARIUM FROM 20 TO 55 PERCENT BY WEIGHT AND OF AT LEAST ONE ORTHOPHOSPHATE OF AN ELEMENT OF THE GROUP CONSISTING OF MAGNESIUM, CALCIUM, STRONTIUM AND BARIUM FROM 45 TO 80 PERCENT BY WEIGHT.
References Cited (Backward Citations)
US2294844A
Cited
US2278501A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-08-14 | 1965-02-13 | 1965-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-08-14 | 1969-02-13 | 1969-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-08-14 | 1973-02-13 | 1973-08-15 | $7700.00 | Window Closed / Lapsed |