Patent ID: 6560041
Filing Date: 2003-05-06
Classification: G02B,G03B

Abstract:
A projection lens apparatus for performing overhead projection of a ray modulated by an image display element on a projection screen, wherein there are positioned:a first lens group arranged at a position closest to the screen and having a negative refracting power; a second lens group arranged at a position second closest to the screen and having a positive refracting power; and a third lens group arranged at a position closest to the image display element and between said second lens group and the image display element, said third lens group having a positive refracting power, and the projection lens apparatus satisfies the following conditions: 1.4f1|/f 2.8<f3/f where, f is a focal length of a whole lens system of the projection lens apparatus, f1 is a focal length of said first lens group, and f3 is a focal length of said third lens group.