| 摘要 |
PURPOSE:To eliminate the need to use an Ftheta lens which is designed complicatedly and expensive by arranging a reflector which corrects deviation between a photoscanner and a projection surface. CONSTITUTION:A beam B from a laser light source 4 is passed through an optical modulator 5 and transmitted through a lens system 6 to illuminate the photoscanner 1 such as a polygon mirror, and the light is scanned by the photoscanner 1 to illuminates the reflector. When a margin mirror is used, the beam B is refracted by an incidence surface 3a, reflected by a reflecting surface 3b, and further refracted when projected from the incidence surface 3a to the projection surface 2. Namely, the beam B is refracted twice and reflected once by the margin mirror to correct aberrations three times, so the reflection direction is easily corrected correspondingly and the margin mirror differ in the distance from the incidence surface 3a to the reflecting surface 3b at respective parts, so the length of the optical path is converted. |
