Zoom lens
US6307685A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1998 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Aug 31, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/143105
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens includes, in the order named from an object side: a first lens group having a positive focal length; a second lens group having a negative focal length; and a third lens group having a positive focal length. A magnification is changed by moving said second and third lens groups in an optical axis direction of said zoom lens, and satisfies the following condition, EQU 3.0<Lt/(LZ)<6.0 where Lt represents a distance between a lens surface closest to the object side of said first lens group and an image plane, L represents a diagonal length of the image plane, and Z represents a variable magnification ratio showing a ratio of a focal length at a wide angle end to a focal length at a telephoto end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.