| 摘要 |
A light beam (L) from a laser source (62) impinges upon a deflection mirror surface (651): in a plane defined by the pivot axis of the deflection mirror and the surface normal of the deflection mirror in its neutral state at an acute angle ( gamma ) with respect to the surface normal NL to the deflection mirror surface (651), and the light beam scans in a main scanning direction (X). Since the light beam is incident upon the deflection mirror surface (651) along the direction of the pivot axis, the length of a movable plate (653) in the main scanning direction (X) may be relatively short. Further, a first optical system (63) shapes the light beam incident upon the deflection mirror surface (651) into an elongated cross sectional shape which is long in the main scanning direction (X), and the movable member (653) is finished as an elongated strip which elongates in the main scanning direction (X). Hence, the movable plate (653) is light-weight and can pivot stably at a faster speed than in a conventional apparatus. <IMAGE> |
