Zoom lens
US6084721A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 1, 1998 |
| Grant date | Jul 4, 2000 |
| Priority date | — |
| Expiry date | Dec 1, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens has, in succession from the object side, a first lens unit fixed during a focal length change and having positive refractive power, a second lens unit moved along the optical axis thereof during the focal length change, a third lens unit for correcting the fluctuation of the image plane resulting from the focal length change, and a fourth lens unit fixed during the focal length change and having positive refractive power. The second lens unit has a lens subunit of negative refractive power and a lens subunit of positive refractive power. The lens subunits are moved at different speeds during the focal length change, and the conditions of the lens are satisfied to correct the fluctuations in aberration during the focal length change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.