Patent ID: 6650486
Filing Date: 2003-11-18
Classification: G02B

Abstract:
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 in sequence, said first lens being a biconcave lens disposed at said front side of said lens unit, said second lens being a biconvex lens, said third lens being a biconcave lens, said fourth lens being a positive meniscus lens, said fifth lens being a positive lens with a surface of facing said objective side having a curvature radius larger than the curvature radius of the opposite surface; said first lens and said fourth lens being made of plastic having at least one of which having a non-spherical surface, said second lens, said third lens and said fifth lens being made of glass and said aperture being arranged between said first lens and said second lens.