| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a means capable of controlling light volume in stepless manner, allowing light volume control at a desired resolution, while preventing complication of hardware. <P>SOLUTION: A diaphragm 25 having a fixed aperture is arranged on a pupil surface of a lighting optical system 31 that illuminates a reticle 19 using the light from a light source 30. A zooming optical system 28, otherwise a second diaphragm 36 having a variable aperture area, is provided which controls illumination light that passes the fixed aperture by enlarging or reducing the irradiation range of the light from the light source to a region of the diaphragm containing the fixed opening. <P>COPYRIGHT: (C)2008,JPO&INPIT |
