Zoom optical system
US4132463A · kind A · utility
23Cited by
5References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1976 |
| Grant date | Jan 2, 1979 |
| Priority date | — |
| Expiry date | Oct 29, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B17/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom optical system is composed of a positive focusing lens group, a negative variating lens group, a negative compensating lens group and a positive rear fixed lens group. A rotating grooved cam moves the variating lens group and the compensating lens group in a given relation to each other along the optical axis in the normal focusing range. The focusing lens group is moved along the optical axis normal range for focusing. The variating lens group is kept stationary on the optical axis while the compensating lens group is moved along the optical axis during close-range focusing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.