Zoom lens system
US5815321A · kind A · utility
7Cited by
7References
33Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 2, 1996 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Oct 2, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/145113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system has four lens units. The first, third and fourth lens units thereof are lens units of positive power. The second lens unit thereof has negative power. During zooming, the first lens unit is moved. During focusing, the second and third lens units are moved and a distance between the third and fourth lens units is varied. The third lens unit is moved toward an object side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.