Zoom optical system
US6411443B1 · kind B1 · utility
19Cited by
9References
28Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1999 |
| Grant date | Jun 25, 2002 |
| Priority date | — |
| Expiry date | Aug 31, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system composed, in order from the object side, of a first lens unit which has a positive power or is powerless, a second lens unit which has a positive power, a third lens unit which has a positive power and a fourth lens unit which has a negative power, and configured to change its magnification by varying airspaces reserved between the lens unit. The fourth lens unit is composed of a single lens element or the optical system as a whole is composed of lens element in a number not exceeding twice a number of movable lens units. The optical system is composed of a small number of lens elements and compact.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.