| 摘要 |
PURPOSE:To easily correct magnification error caused by the focal distance error of an image formation lens while saving labor by forming a mirror to be bent and bending the mirror to change the magnification of an image to be formed in a photodetecting means. CONSTITUTION:A second mirror 11 is formed so as to be bent for displacing a central part 11B to both ends 11A in the lengthwise direction. On the face of the image formation lens side at the both ends 11A of the mirror 11, an abutting means 13 is installed a case 12, and at the part of the case 12 facing to the central part 11B in the lengthwise direction of the mirror 11, a block 14 is installed. Then, an adjusting screw 15 to be abutted to the center of the mirror 11 in the lengthwise and height-wise directions is screwed to the block 14. Next, in order to correct the magnification error caused by the focal distance error of an image formation lens 7, the adjusting screw 15 is operated and the central part 11B of the mirror 11 is displaced and bent in the direction of the image formation lens so as to change the curvature of the mirror 11. |
