Snider & Associates
Projection lens having all glass lenses in a second lens group
 Four groups of six lenses comprising a plastic lens having weak refracting power, three glass lenses of convex, concave, and convex yielding a major part a refracting power of the projection lens as a whole, a plastic lens having a weak refracting power, and a lens having a concave surface directed onto the screen side are successively disposed from the screen side, whereby the plastic lens with a temperature-correcting function is omitted, thus cutting down cost. Successively disposed from the screen side are G.sub.1 made of a plastic lens L.sub.1 having a weak refracting power and at least one aspheric surface, G.sub.2 made of three glass lenses of convex, concave, and convex L.sub.2 to L.sub.4 yielding a major part of the refracting power of the projection lens as a whole, G.sub.3 made of a plastic lens L.sub.5 having a weak refracting power and at least one aspheric surface, and G.sub.4 made of a lens L.sub.6 having at least one aspheric surface and a concave surface directed onto the screen side. 
Fuji Photo Optical Co., Ltd.
G G
G02B G02B
inventional inventional
Hiroshi
Yamada