Zoom lens system, imaging optical device, and digital appliance
US9256059B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jul 4, 2013 |
| Grant date | Feb 9, 2016 |
| Priority date | — |
| Expiry date | Jul 4, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/69
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A zoom lens system having a negative first lens group and a positive second lens group, from an object side, and achieving zooming by varying a group-to-group distance. The second lens group includes a three-element cemented lens which is a set of three lens elements cemented together including, from the object side, a negative first lens, a positive second lens, and a negative third lens, and the three-element cemented lens fulfills conditional formulas 0.08<(rs2+rs1)/(rs2−rs1)<0.5, 27<v2-v1<40, 20<v2-v3<38 (rs1, rs2 represent the curvature radius of the sides of cemented surfaces of the three-element cemented lens on the object side and the image side respectively, and v1-3 represent the Abbe numbers of the first to third lenses of the three-element cemented lens).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.