Finder lens system in viewfinder
Abstract
Abstract A VIEWFINDER LENS SYSTEM FOR A HOLLOW PENTA-ROOF-TYPE REFLECTING MIRROR HAVING AN OBJECT LENS AND FOCAL PLANE ON ONE SIDE OF THE REFLECTING MIRROR AND A POSITIVE MENISCUS LENS GROUP LOCATED AT 90* ALONG THE OPTICAL AXIS ON THE OTHER SIDE OF THE REFLECTING MIRROR ALONG WITH A NEGATIVE LENS SPACED FROM SAID POSITIVE LENS GROUP FURTHER ALONG THE OPTICAL AXIS. WITH THE USE OF SUCH HOLLOW REFLECTING MIRROR IT IS DESIRED TO INCREASE THE MAGNIFICATION, AND THIS IS ACCOMPLISHED BY DESIGNING THE COMPOUND FOCAL LENGTH OF THE POSITIVE AND NEGATIVE LENS GROUP TO BE AT LEAST EQUAL TO THE FOCAL LENGTH OF THE OBJECT LENS, AND THE FOCAL POINT OF THE POSITIVE AND NEGATIVE GROUP TO COINCIDE WITH THE FOCAL PLANE.
Inventors
- 👤 Yohei Ikezu
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |