US3672920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical glass having a high refractive index and a low dispersion
Assignee: Hoya Glass Works Ltd
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Filing: 1970-05-26
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Granted: 1972-06-27
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Expires: 1990-05-26
Abstract
Abstract AN OPTICAL GLASS HAVING A HIGH REFRACTIVE INDEX, A LOW DISPERSION AND A HIGH STABILITY DURING MELTING CAN BE PRODUCED BY ADDING 5-10 WEIGHT PERCENT OF MGO TO A COMPOSITION OF THE B2LA2O8THO2 SYSTEMS OPTIONALLY CONTAINING SIO2, ZRO2 AND/OR TA2O5.
Inventors
- 👤 Hachiro Ishiguri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:00
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/064; C03C3/068; C03C3/12; C03C3/14; C03C3/15; C03C3/155; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/903
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |