Patent ID: RE39911

Claim:
A projection lens for forming an image of an object, said projection lens having a focal length f 0 and consisting in order from its image side of: (A) a first lens unit having a focal length f 1 and comprising : (i) a lens element having a focal length f E1 , ; and said lens element comprising (ii) at least one aspherical surface for correction of distortion; and (B) a second lens unit having a focal length f 2 and consisting in order from its image side of: (i) a first lens subunit having a focal length f 2 S1 ; and (ii) a second lens subunit separated from the first lens subunit by an airspace and having a focal length f 2 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: |f1|/f0 > 0.75; f E1 < 0; f2 > 0; f2/f0 < 2.0 f2 S1 > 0; f2 S1 /f0 < 1.5; and |f2 S2 |/f0 < 1.5.