| 摘要 |
A projection optical system which uses, for example, an ArF excimer laser beam and can ensure a good imaging performance for an extended period while avoiding the variations in refractive index and the effect of the intrinsic double refraction of a fluorite containing a high-frequency component. A projection optical system for forming the demagnified image of a first plane (R) on a second plane (W). A first light transmitting member (L 23 ) disposed closest to the second plane side and having almost no refraction power is provided. When the distance between the first light transmitting member and the second plane is WD, a numerical aperture on the second plane side NA, and the center wavelength of a light used Lx10<SUP>-6</SUP>, the condition 0.06<WDNA/L<0.23 is satisfied. Or, a first light transmitting member disposed closest to a second plane side and having almost no refraction power, and a second light transmitting member (L 22 ) disposed adjacent to the first plane side are provided. When an air-equivalent length from the second light transmitting member to the second plane is OD, the condition 0.1<ODNA/L<0.4 is satisfied.
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