| 摘要 |
PURPOSE: To reduce a projection system by causing beams to pass through first lens groups, a beam splitter and second lens groups and causing the beams to pass through the second lens groups in a convergent mirror and third lens groups in the beam splitter. CONSTITUTION: The first lens groups 12 and 13, the second lens groups 14 and 15, the beam splitter 17, the third lens groups 18 and 19, the convergent mirror 20 and the fourth lens groups 2I-24 are provided. The low-order coma aberration and the spherical aberration of the convergent mirror 20 are corrected by the third lens groups 18 and 19. An astigmatic aberration for all dimensions is mainly corrected by the fourth groups 21-24, and the space generates the high- order coma aberration and a distortion aberration. A low-order distortion aberration is corrected by selecting optimum reflection force between the second groups 14 and 15 and the fourth groups 21-24. The color of an axial direction is balanced against the color aberration of a visual curvature and the colors in the lateral direction of the second groups 14 and 15 are balanced against the fourth groups 21-24. Thus, the size of an image can be reduced. |
