Patent ID: 6324014
Filing Date: 2001-11-27
Classification: G02B

Abstract:
A projection lens for forming an image of an object, said projection lens having a focal length f0 and consisting in order from its image side of:(A) a first lens unit having a focal length f1 and comprising:(i) a lens element having a focal length f.sub.E1 ; and(ii) at least one aspherical surface for correction of distortion; and(B) a second lens unit having a focal length f2 and consisting in order from its image side of:(i) a first lens subunit having a focal length f2.sub.S1 ; and(ii) a second lens subunit separated from the first lens subunit by an airspace and having a focal length f2.sub.S2, said second lens subunit comprising: (a) at least one aspherical surface for correction of spherical aberration, and (b) means for providing axial color correction for the lens system;wherein:.vertline.f1.vertline./f0 > 0.75; f.sub.E1 < 0; f2 > 0; f2/f0 < 2.0 f2.sub.S1 > 0; f2.sub.S1 /f0 < 1.5; and .vertline.f2.sub.S2.vertline./f0 > 1.5.