| 摘要 |
PURPOSE:To facilitate machining and assembling and to compact an optical scanning device by using a cylindrical lens as a 1st lens constituting an ftheta lens system and a toric lens as a 2nd lens. CONSTITUTION:The ftheta lens system 4 consists of two lenses, i.e., the cylindrical lens 41 and toric lens 42 which have refracting power only in a plane of deflection, so the refracting power of either lens is freely settable in the plane of deflection irrelevantly to the other direction. Consequently, the free refracting power is set for the two lenses in the plane of deflection and the two lenses whose refractive power is freely settable are used to form equal-speed scanning performance. Consequently, the design, machining, and assembly become extremely easy. |
