Zoom lens
Abstract
Abstract An optical system of zoom lens has four lens groups or, from front to rear, a first lens group of positive power for focusing, a second lens group of negative power for variation of the image magnification, a third lens group of negative power for image shift compensation, and a fourth lens group of positive power for forming an image of an object. The fourth lens group has two component lens group, i.e., from front to rear, a first component lens group and a second component lens group. The fourth lens group's first component lens group has five lenses, namely, from front to rear, a biconvex first lens with a strong curvature at its rear surface, a biconvex second lens with its front surface of strong curvature, a third lens of negative power with a strong curvature at its front surface, a fourth lens of positive power with a strong curvature at its front surface, and a fifth lens of positive power with its front surface of strong curvature. The fourth lens group's second component lens group has three lenses, namely, from front to rear, a first lens of negative power with a strong curvature at its rear surface, a biconvex second lens with its rear surface having strong curvature and a biconvex third lens with a strong curvature at its front surface.
Inventors
- 👤 Muneharu Sugiura
Bibliographic Details
Claims Analysis
Total Claims: 3References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |