Triplet type objective with a diaphragm arranged behind the lens system
US4892398A · kind A · utility
12Cited by
3References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1988 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Nov 17, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B9/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a triplet type objective for a compact lens shutter camera with a diaphragm arranged behind the lens system, the first and the second lens elements are formed of plastic and the third lens element is formed of glass, so that it is advantageous in manufacturing cost and weight. Therefore, an F No. of the objective is small and aberrations, for example astigmatic difference, are corrected well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.