| 摘要 |
Provided is a projection-type video display device in which further reduction in size of a projection optical system and further reduction of projection distance are realized. This projection-type video display device is provided with a lens group including a plurality of lenses, a free-form surface lens, and a free-form surface mirror for projecting light from the free-form surface lens onto a screen. The lens group is provided with: a biconvex first lens, a smaller curvature radius of which is oriented toward a video display element side; an aspherical second lens; a biconvex third lens; a biconcave fourth lens; a biconvex fifth lens; a biconvex sixth lens, a smaller curvature radius of which is oriented toward a magnification side; a meniscus-shaped seventh lens, a convex face of which is oriented toward a reduction side; a biconcave eighth lens; a biconvex ninth lens, a smaller curvature radius of which is oriented toward the magnification side; and a meniscus-shaped tenth lens, a convex face of which is oriented toward the magnification side. The third through fifth lenses constitute a triplet lens, and the free-form surface lens is meniscus-shaped, a convex face of which is oriented toward the magnification side. |
