Zoom lens
US5790316A · kind A · utility
20Cited by
4References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1995 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Apr 20, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens is disclosed comprising, from front to rear, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a flare cut stop for cutting a lower marginal ray of an off-axial bundle of rays for a maximum image height, a third lens unit of positive refractive power and a fourth lens unit of positive refractive power, wherein the second and third lens units move axially to effect zooming, while either varying the aperture diameter of the flare cut stop or axially moving the flare cut stop to thereby cut the harmful rays for good optical performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.