| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve ease of observation by reducing a difference in lightness of an image between a high-magnification observation and a wide-field observation. <P>SOLUTION: An observation optical system includes an objective optical system 2 comprising an afocal optical system which converges light from an observation object A; an image formation optical system 4 with positive power which images the light converged by the objective optical system 2; and an intermediate optical system 3 which includes a first optical system 3a and a second optical system 3b provided to be alternatively inserted into and extracted from an optical path between those objective optical system 2 and image formation optical system 4, the first optical system 3a being a collimation optical system with positive power and the second optical system 3b being an observation optical system as a substantially afocal optical system. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
