Patent ID: 6940661
Filing Date: 2005-09-06
Classification: G02B

Abstract:
1. A lens assembly, comprising an aperture, and a lens unit having a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged behind said aperture in sequence, said first lens being a biconvex lens disposed at the front side of the lens unit, said second lens being a biconcave lens, said third lens being positive lens with a surface of facing the image side having a curvature radius larger than the curvature radius of the opposite surface, said fourth lens being a negative meniscus lens and said fifth lens being a positive lens with a surface of facing the image side having a curvature radius larger than the curvature radius of the opposite surface; said fourth lens and said fifth lens being attached together to form a compound lens, said aperture disposed in front of said first lens; wherein said lens unit of said lens assembly has conditions as described hereunder:  0.45< f 1 / f< 0.9  (1) wherein f