Patent ID: 6124979
Filing Date: 2000-09-26
Classification: G02B

Abstract:
A projection lens device for projecting an original image being displayed on an image source upon a screen, comprising in sequence from the screen:a first lens group having a negative refractive power as an entire system thereof, and including at least a meniscus lens of negative refractive power, which has a convex surface toward the screen side;a second lens group having a positive refractive power as an entire system thereof, and including laminated or cemented lenses having a negative refractive power, one of which has convex surfaces at both sides and a first Abbe's number and the other of which has concave surfaces at both sides and a second Abbe's number being smaller than the first Abbe's number; anda third lens group having a negative refractive power as an entire system thereof, and including at least a lens which has a concave surface at a center thereof toward the screen.