Zoom lens, and image pickup apparatus and image projection apparatus using the same
US6710931B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 23, 2000 |
| Grant date | Mar 23, 2004 |
| Priority date | — |
| Expiry date | May 23, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144511
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens including, in order from an object side to an image side, a first lens unit L1 of negative refractive power, a second lens unit L2 of positive refractive power, a third lens unit L3 of negative refractive power, and a fourth lens unit L4 of positive refractive power, wherein, during variation of magnification from a wide-angle end to a telephoto end, L1 moves with a locus convex toward the image side, L2 moves toward the object side in such a way as to decrease a separation between L1 and L2, L3 moves toward the object side in such a way as to increase a separation between L2 and L3, and L4 moves toward the object side in such a way as to decrease a separation between L3 and L4, and wherein the Abbe number and refractive index of a negative lens included in L1 are appropriately set.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.