Zoom lens
US4437733A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1981 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Jul 2, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens comprises a magnification changing system and a relay lens system succeeding the magnification changing system. The magnification changing system comprises, in succession from the object side, a first group as a focusing portion having a positive refractive power, a second group as a variator portion having a negative refractive power and movable along the optical axis to thereby change chiefly the focal length, and a third group as a compensator portion having a negative refractive power and maintaining the image plane fluctuated by movement of the variator portion at a predetermined position. The relay lens system comprises a fourth group as a forward relay system group having a positive refractive power and a fifth group as a rearward relay system group having a positive refractive power. The fourth group has three positive lens components of which at least the middle lens component is a cemented lens component having a convex cemented surface in the direction of the image side. The fifth group has at least one positive lens component which is a cemented lens having a convex cemented surface on the object side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.