| 摘要 |
PURPOSE:To reduce an image distortion by providing plural reflecting surfaces centering around one point of a production extended to a rotation axis from a scanning center point of the reflecting surface which has been inclined by about 45 deg. virtually against the rotation axis and having a different angle, respectively, on a rotary polygon mirror. CONSTITUTION:A rotary polygon mirror 3 is provided with the reflecting surface 3-1 whose Q0 has been inclined by 45 deg. against a rotation axis 3a, and the reflecting surfaces 3-2, 3-3 and 3-4 having different inclination angles Q2-Q4, respectively. Accordingly, when the rotary polygon mirror 3 is rotated, the reflecting surfaces 3-1, 3-2 and 3-3 opposed to a visual field are deflected successively in the vertical direction centering around a point A, and against an incident optical axis 5a-1 of an incident light to the reflecting surface from the visual field, incident optical axes 5a-2, 5a-3 of an incident light to the reflecting surfaces 3-2, 3-3 scan the visual field by being shifted by an angle 2theta1 and 2theta2, respectively in the vertical direction in accordance with the inclination angles theta2, theta3, respectively. In such a way, when a position of the point A is determined by adjusting the inclination angle so that a distance CD extending from a point C being a pupil position 2-1 to a point D and a distance between points B, D coincide with each other, the generation of an overlap between blocks and a gap is prevented, and an image distortion is eliminated. |
