| 摘要 |
PURPOSE:To enable an incidence angle of an illumination light to be adjusted easily and highly accurately by providing a lens transportation means for selectively moving a lens which is inserted in series into a light path of an illumination optic system in a reticle alignment optic system in the direction at right angle to a light axis. CONSTITUTION:An incidence angle of an illumination light 115 is adjusted by moving a lens 117 which is inserted in series into a light path of an illumination optic path 112 in the direction at right angle to a light axis of this lens 117. In this case, the lens 117 can be easily moved in a direction at right angle to the light axis highly accurately and at a fine distance by a drive mechanism with a large deceleration ratio, for example wedge type drive mechanism 124-127, thus enabling the incidence angle of the illumination light to be adjusted highly accurately and easily. |
