| 摘要 |
A projection lens system has first, second and third lens groups. The first lens group with combined focal length f1 has, in order from a screen side, a first negative meniscus lens, a second negative meniscus lens with focal length f12, refractive index n12 and screen side surface radius of curvature R12a, and a negative biconcave lens with focal length f13. A second lens group consists of a positive biconvex lens with a radius of curvature R21b of a surface on a light modulator side of the positive biconvex lens. The system satisfies the following conditions: 1.0<|f12/f1|<4.0; 5.0<|f13/f1|<9.0; 1.75<n12<2.0; and 0.1<|R21b/R12a|<0.8. |
