US3567304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bipartite achromate
Assignee: Eltro GmbH and Co
•
Filing: 1969-01-30
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Granted: 1971-03-02
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Expires: 1989-01-30
Abstract
Abstract A BIPARTITE ACHROMATE INCLUDING A COLLECTIVE LENS OF BARIUM FLUORIDE AND A DIVERGENT LENS OF SAPPHIRE OR MAGNESIUM OXIDE, THE ABBE NUMBER OF THE COLLECTIVE LENS BEING HIGHER THAN THAT OF THE DIVERGENT LENS AND THE INDEX OF REFRACTION BEING LOWER. THE ABBE NUMBER IS A FUNCTION OF THE REFRACTION INDICES OF THE OPTICAL MATERIALS TO BE USED FOR THE INDIVIDUAL LENSES.
Inventors
- 👤 Hans Kruger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:48
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/14
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |