| 摘要 |
PURPOSE:To obtain a projector lens which has high performance and sufficient X- ray shielding capability by using a small number of lenses, by providing a single positive lens made of plastics, X-ray shielding plane glass plate, single double-convex lens, and negative plano-concave lens successively from the screen side. CONSTITUTION:From the screen side to the projector tube side, single positive plastic lens L1, X-ray shielding multilayered frint plane glass plate P having 2-3mm. thickness, single double-convex plastic lens L2, and single negative plastic lens L3 are provided; surface r1 of the 1st lens, surface r4 of the 2nd lens and surface r5 of the 3rd lens are made unspherical, and surface r2 of the 1st lens and surface r6 of the 3rd lens are formed as planes. Thus, the projector lens which has high performance and enough X-ray shielding performing by using a small number of lenses can be obtained. |
