| 摘要 |
A projection lens for projecting onto a screen an enlargement of an image appearing on a CRT wherein comma and chromatic aberration , which degrades imaging quality, can be properly corrected comprises 4 lens units. The projection lens comprises, in the order from the screen end, a first lens unit of positive optical power having a strong convex surface facing the screen end, a second lens unit comprising a biconvex lens element of positive optical power and a lens element of negative optical power having a concave surface facing the screen end, a third lens unit of positive optical power at an optical axis having a convex surface facing the screen end, and a fourth lens unit of negative optical power having a concave surface facing the screen end. |
