| 摘要 |
PURPOSE:To correct the curvature of an image with high accuracy by detecting the vibration position of a first image forming optical system with a detecting means consisting of a detecting light source and a light receiving part, and controlling the vibration based on a detecting signal. CONSTITUTION:The cylindrical lens 22 of a first image forming optical system is provided so as to be movable or vibratable along an optical axis R, and executes the correction of the curvature of image. A detecting means for detecting the movement is constituted of the detecting light source 20 and the light receiving part 21, and a luminous flux from the light source 20 is limited and received by a control member 23. By the receiving light quantity of the light receiving part 21, the moving amount of the cylindrical lens 22 is known, and the detecting signal is brought to feedback to an actuator for moving or vibrating the lens 22. In such a manner, an exact control corresponding to a deflection scan can be executed, and the curvature of the image can be corrected with high accuracy. |
