Patent ID: 6124978
Filing Date: 2000-09-26
Classification: G02B

Abstract:
A projection lens having an enlarging side and a reducing side, said projection lens comprising, in order from the enlarging side of the projection lens:a first lens group consisting of a single positive lens element;a second lens group consisting of a single negative meniscus lens element;a third lens group having negative refractive power and formed of a negative lens element and a positive lens element;a fourth lens group consisting of a single positive lens element; and,a fifth lens group consisting of a single positive lens element,whereinthe maximum angle of a principal ray relative to the optical axis on the reducing side of the projection lens is 2.5 degrees or less, and the following conditions are satisfiedn.sub.AVE >1.7540<v.sub.AVE <55wheren.sub.AVE is the average value of the refractive index of the positive lens elements of said projection lens, andv.sub.AVE is the average value of the Abbe constant of the positive lens element of said projection lens.