| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact high-performance projection optical system wherein various kinds of aberration including distortion are satisfactorily corrected while securing a satisfactorily large numerical aperture and a satisfactorily wide image forming area. SOLUTION: The optical system is provided with a 1st lens group (G1) having a negative refractive power, a 2nd lens group (G2) having a positive refractive power, a 3rd lens group (G3) having a negative refractive power, a 4th lens group (G4) having a positive refractive power and a 5th lens group (G5) having a positive refractive power. The 1st lens group includes two negative lenses and one aspherical optical surface, the 2nd lens group includes four positive lenses continuously arranged on the 2nd face side, the 3rd lens group includes two negative lenses and one aspherical optical surface, the 4th lens group includes five positive lenses, one negative lens and one aspherical optical surface, and the 5th lens group includes one negative lens. COPYRIGHT: (C)2004,JPO&NCIPI
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