Variable field curvature lens system
US4231636A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 19, 1978 |
| Grant date | Nov 4, 1980 |
| Priority date | — |
| Expiry date | Jul 19, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/00
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical lens system is provided having the capability of selectively varying the peripheral field curvature to improve focusing for nonplanar objects and for special photographic effects. The lens system can include in sequence, a first lens group of positive refractive power, a second lens group of negative refractive power and a third lens group of positive refractive power. The specific refractive power of the first and second lens group are designed so that the optical ray traces from an object on the optical axis at infinity will run approximately parallel with the optical axis in the space between the second and third lens groups. The first and second lens groups being movable as a unit relative to the third lens group to change the field curvature without varying the back focal distance of the lens system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.