| 摘要 |
PURPOSE:To secure an invariably stable reduction rate by allowing a reduction lens system main body to move finely in the direction of an exposure axis between a lens support structure and a support structure body on the side of a device main body, and slanting the surface which is perpendicular to the exposure optical axis in an optional direction for reduction. CONSTITUTION:The reduction lens main body 5 is coupled with the lens support structure 1 and piezoelectric actuators 6 are arranged at, for example, three circumferential equal division positions of the coupling part between both the support structure bodies. Further, springs 7 are arranged at proper positions on the same circumference to couple both the support structure bodies 1 and 2 with mutually constant holding forces. The relation between the axial displacement and applied voltage of the piezoelectric actuators 6 is calculated by mounting an actuator which is calibrated in advance and commanded through respective piezoelectric actuator control circuits 8. Consequently, a proper magnification state wherein there is no image distortion is generated and the stable reduction rate can be secured. |
