| 摘要 |
PURPOSE:To obtain an excellent distortion characteristic and excellent image plane flatness over a wide view angle range by providing a troidal lens arranged between a deflector and a spherical mirror and setting light which is made incident on the deflector and the axis of rotation of the deflector at an angle other than 90 deg.. CONSTITUTION:Luminous flux radiated by a light source 1 is made to scan at an equal angular speed through the deflector 10 and this scanning luminous flux is passed through the troidal lens 15 and reflected by the spherical mirror 20, and converged on the surface of a photosensitive body 30 to form an image by main scanning by the deflector 10 and subscanning by the movement of the photosensitive body surface. Further, the incident light to the deflector 10 and the axis 11 of rotation of the deflector 10 are set at an angle other than 90 deg.. Therefore, the incident light to the spherical mirror 20 and projection light are separated spatially and the projection light from the deflector 10 becomes easy to deflect toward the photosensitive body 30 by the reflecting mirror. Consequently, the excellent distortion characteristic and excellent image plane flatness are obtained on the convergence plane over the wide view angle range. |
