| 摘要 |
PURPOSE:To enable slit exposure always at proper exposure distribution by moving a shading plates perpendicularly to the optic axis of the lens and thereby changing the amount of interception of exposure pensil of light rays and making distribution of exposure in longitudinal direction of exposed part uniform. CONSTITUTION:Two shading plates 10, 11 are placed at positions 3A, 3B of the end face of a lens, or, the shading plate 10 is placed at the position 3A and shading plate 11 at the position 3D. In the former method, shading plates 10, 11 are symmetrical to the optical axis L, and the plates are made so that they are movable symmetrically to the optic axis L in the direction corresponding to longitudinal, or left and right, direction of the exposed part. In the latter method, shading plates 10, 11 are placed in the same side in relation to the optic axis L of the lens, and they moves in left and right direction in a pair and intercept exposing pencil of light symmectrically. By this way, the amount of interception of exposing pencil of light is changed and distribution of amount of exposure is made uniform. |
