Compact zoom lens
Abstract
Abstract A zoom lens comprising four lens groups, the first group for focusing control having a positive focal length, the second group as a variator having a negative focal length, and the third group as a compensator having a positive focal length. The rays emanating from the third group are substantially parallel with respect to a common axis of the lens groups including the fourth lens group which serves as an image-forming lens and which has a positive focal length. The first group has a positive lens of a negative meniscus lens and a bi-convex lens cemented together and a positive meniscus lens, the second group has a negative meniscus lens and a negative lens comprising a bi-concave lens and a positive lens cemented together, and the third group has a negative meniscus lens and a bi-convex lens. The fourth group is composed of a positive meniscus lens, a bi-concave lens, two bi-convex lenses and a negative meniscus lens.
Inventors
- 👤 Sadahiko Tsuji
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |