| 摘要 |
PROBLEM TO BE SOLVED: To enable an installation position in an optical axis direction to be surely defined.SOLUTION: A light tunnel includes a pawl 108 that is inserted into a light tunnel position setting hole 109 provided in an illumination optical system housing 112 as a position reference part and serves as an engagement part, and enables a uniform surface light source to be obtained. In the light tunnel, a spring 113 is provided that serves as an elastic part urging the pawl 108 against the light tunnel position setting hole 109. The pawl 108 is inserted into the light tunnel position setting hole 109 provided in the illumination optical system housing 112, abuts on a first opening edge surface 109a facing an optical axis direction of the light tunnel position setting hole 109, and is pressed by the spring 113. |
