| 摘要 |
PROBLEM TO BE SOLVED: To obtain a photographing optical system having high resolving power and a wide exposure area and constituted of a small number of lenses to be used by providing 1st to 5th lens groups and satisfying specified conditions. SOLUTION: This system projects a pattern on a reticle R to a wafer W and is equipped with the 1st to the 5th lens groups G1 to G5 from a side R to a side W. The 1st group G1 is constituted of positive lenses L1 to L3 , the 2nd group G2 is constituted of negative lenses L4 to L7 , the 3rd group G3 is constituted of the positive lenses L8 to L12 , the 4th group G4 is constituted of the negative lenses L13 to L15 and the 5th group G5 is constituted of the continuous positive lenses L16 to L22 , the negative lens L23 and the positive lens L24 . The lens surfaces of the negative lens L4 and the positive lens L20 on the side W are aspherical. Then, the conditions 0.4<ΣiDi/L<0.6, 0.05<f2 /f4 <6, 0.01<f5 /L<1.2, -0.8<f4 /L<-0.008 and -0.5<f2 /L<-0.005 are satisfied. In the expressions,ΣiDi is the total sum of the center thickness of the lenses, L is a distance from the side R to the side W, and f2 , f4 and f5 are the focal distances of the 2nd, the 4th and the 5th lens groups.
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