Extender lens unit, zoom lens, and image pickup apparatus
US12164089B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 5, 2020 |
| Grant date | Dec 10, 2024 |
| Priority date | — |
| Expiry date | Nov 9, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0025
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An extender lens unit to be inserted into and removed from an optical path in a relay lens unit included in a zoom lens consists of a front unit having a positive refractive power, a middle unit having a negative refractive power, and a rear unit having a negative refractive power. The extender lens unit includes three negative lenses. The middle unit includes a negative lens. An average refractive index of positive lenses included in the extender lens unit, an average refractive index of negative lenses included in the extender lens unit, a focal length of the negative lens included in the middle unit, and a focal length of the middle unit are appropriately set.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.