Zoom lens
US6141157A · kind A · utility
4Cited by
4References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1999 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Jun 17, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144109
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens has, in succession from the object side, a first lens unit of positive refractive power fixed during focal length change, a second lens unit of negative refractive power for focal length change, a third lens unit of negative refractive power for correcting the fluctuation of the image plane resulting from focal length change, and a fixed fourth lens unit of positive refractive power, and a thin layer of resin satisfying a predetermined condition is provided on at least one lens surface of the first lens unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.