Imaging lens and optical apparatus using the same
US5969883A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 11, 1999 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Feb 11, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In an imaging lens suitable for image reading of a four-lens element configuration comprising, successively from the object side, positive, positive, negative, and positive lenses, at least one surface of the fourth lens is made aspherical, whereby lighter weight and lower cost are achieved, while various kinds of aberration are corrected. The four-lens element imaging lens comprises, successively from the object side, positive first and second lenses L.sub.1 and L.sub.2 each having a surface on the object side convex toward the object side, a negative third lens L.sub.3 having a surface on the image side concave toward the image side, and a positive fourth lens L.sub.4 having at least one aspheric surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.