US3675998A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual magnification projection lens
Assignee: American Optical Corp
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Filing: 1970-10-29
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Granted: 1972-07-11
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Expires: 1990-10-29
Abstract
Abstract A TWO-ELEMENT PROJECTION LENS IN WHICH ONE ELEMENT IS SWINGABLY MOUNTED ON AN AXIS PERPENDICULAR TO THE OPTICAL PATH. WHEN THE TWO LENS ELEMENTS ARE POSITIONED ADJACENT EACH OTHER, THEY COMPRISE A LENS HAVING A GIVEN FOCAL LENGTH TO EFFECT A CERTAIN MAGNIFICATION. WHEN THE TWO LENS ELEMENTS ARE SEPARATED BY SWINGING ONE TO AN ALTERNATE POSITION IN THE OPTICAL PATH, THE COMBINED LENS HAS A DIFFERENT FOCAL LENGTH TO EFFECT A DIFFERENT MAGNIFICATION.
Inventors
- 👤 Henry T Wilton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:08
CPC Classifications
G; G02; G02B; G02B15/00; Y; Y10; Y10S; Y10S353/00; Y10S353/03
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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |