US3754816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steep-edge absorption filter
Assignee: Schott AG
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Filing: 1967-11-15
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Granted: 1973-08-28
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Expires: 1987-11-15
Abstract
Abstract There is disclosed glass compositions, i.e., filters characterized by steep edged absorption curves in the wave length range lambda 380 - 475 nm. The filters are prepared by heat treating glass samples having the following composition at a temperature between 550* and 620* C at which CdS + ZnS color centers are formed: SiO2 44-66 wt-%K2O8-24 wt-%ZnO12-24 wt-%B2O3 0-8 wt-%Na2O0-4 wt%Al2O3 0-3 wt-%MgO0-6 wt-%CaO0-12 wt-%BaO0-8 wt-%SrO0-12 wt%ZnS0.5-2.4 wt-%CdS0.5-1.5 wt-%
Inventors
- 👤 W Ritze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:11
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/02; C03C14/00; C03C14/006; C03C3/00; C03C3/04; C03C3/076; C03C3/078
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1864858A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |