| 摘要 |
PURPOSE:To improve the accuracy of scanning and to miniaturize the device by using two correcting plane mirrors and setting them so that the first and second reflecting light on the polarizing reflecting surface may position at a crossing line of plane mirror and polarizing reflecting surface, which crosses orthogonally with the rotating axis. CONSTITUTION:The ridgeline 28 where correcting plane mirrors 24, 26 cross is orthogonal against the rotating axis 12 of polygon rotating mirror 10. Incident beam 201 is reflected at polarizing reflecting surface 16 and then again reflected at plane mirror 24 and 26 each one time and guided to a scanning plate 34 through a condensor lens 32. Thus the optical beam 201 reflects at the polarizing reflecting surface two times, and the position and an included angle gamma of plane mirrors 24, 26 are determined so that the reflecting position of first and second time may be placed on a plane 30 which, at the time when ridgeline 28 and polarizing reflecting surface are parallel, crosses orthogonally against rotating axis 12 and runs center and its around of the polarizing reflecting surface 16. By determining in this manner, the reflected light 202 runs parallel and condensed to the same position of scanning surface even if deviation may occur to surface and axis of polarizing reflecting surfaces. This results in enhancement of accuracy of scanning and miniaturization of the device. |
