Imaging lens
US6985309B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 29, 2004 |
| Grant date | Jan 10, 2006 |
| Priority date | — |
| Expiry date | Jul 3, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/06
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An imaging lens includes, in order from the object side: a first lens component of negative refractive power with two aspheric surfaces including a concave surface near the optical axis on the image-side; a second lens component of positive refractive power with a convex surface on the object side; a third lens component having positive refractive power and including lens elements having positive and negative refractive powers; and a fourth lens component having an aspheric surface on the image side that is convex near the optical axis and is concave at the periphery. The imaging lens satisfies a specified condition to assure a sufficient back focus for insertion of additional optical elements, a sufficiently small imaging lens diameter, and favorable correction of aberrations. The imaging lens has a wide picture angle, consists of only 5 lens elements in the disclosed embodiments, and is particularly suited for a text imaging camera.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.