| 摘要 |
PURPOSE:To perform slit exposure with an invariably adequate exposure distribution even when copying magnification is switched, by forming a specific light- shielded area through a light shielding member, and increasing the width of the light-shielded area as the magnification of an optical variable power system is decreased. CONSTITUTION:Light shielding members 9 and 10 are arranged near the incidence end and emission end of a lens 3 to form lengthwise rectangular light- shielded areas at right angles (perpendicular to paper in figure) to the length- wise direction of a slit (right and left direction in figure) and consequently part of reflected luminous flux from an original surface 1 is cut off to correct irregularity of illuminace in the slit lengthwise direction. Then, the width of said light- shielded areas is increased as the magnification of the optical variable power system is decreased. For example, the light shielding members 9 and 10 consist of plural plates 9-1, 9-2, etc., crossing the optical axis at right angles, and those plates are moved in the slit lengthwise direction to vary said light-shielded areas in width. |
