| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection optical system that covers a wide variable range and is designed also for a high-definition image display element, in application to a proximity type projector.SOLUTION: In a 1-2 lens group 42, a reduction-side fixed lens group (first fixed lens group H1) that is a fixed group is arranged on the most reduction side; an enlargement-side fixed lens group (second fixed lens group H2) that is a fixed group is arranged on the most enlargement side; and moving lens groups (lens groups F1 to F3) that move in focusing associated with variation of magnification are arranged between the first and second lens groups, so as to enable correction effective to suppress a fluctuation in aberration. Thus, even when a second optical group 40b is constituted of one mirror MR, appropriate aberration is included in a primary image so as to provide a good image with less aberration, the image to be ultimately projected on a screen through the second optical group 40b.SELECTED DRAWING: Figure 3 |
