Compact zoom lens system
US5301065A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | Sep 4, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/142
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system consists of four lens elements arranged in two groups. Counting from the object side, the first two elements form a front lens group with positive refracting power and the last two elements form a rear lens group with negative refracting power. An airspace is reserved between the front lens group and the rear lens group and it is made variable for zooming. The first lens element in the front lens group is a negative lens element and has its concave lens surface directed toward the object side. Both the two lens elements in the rear lens group are negative lens element. In the lens composition, both the front lens group and the rear lens group at least include an aspherical lens surface respectively for aberration correction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.