| 摘要 |
PROBLEM TO BE SOLVED: To obtain a projection lens for a projector where peripheral extinction is reduced, an excellent telecentric property can be secured on a reduction side and whose aperture ratio can be made large, the various kinds of aberration can be made excellent and the number of lenses is few by making an angle formed by a main light beam from a lens and an optical axis to be <=2.5 deg. and satisfying a specified expression. SOLUTION: A first lens L1 consisting of a positive lens, a second lens L2 consisting of a negative lens, a joint lens of a third lens L3 consisting of a negative lens and a fourth lens L4 consisting of a positive lens, a fifth lens L5 consisting of a positive lens and a sixth lens L6 consisting of a positive lens are arrayed in order from a magnifying side and satisfy expressions [I]-[VI]. The expression [I] is nAVE>1.75, the expression [II] is 40<νAVE<55, the expression [III] is 0.15<F/F12<0.5, the expression [IV} is n2<1.65, the expression [V] is R4/F>0.32 and the expression [VI] is D3/F<0.2.
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