Patent ID: 6208448
Filing Date: 2001-03-27
Classification: G02B

Abstract:
A scanning optical apparatus comprising:a light source which emits a ray;a first lens unit for forming a luminous flux using the ray and having at least one or more positive lens elements;a scanner for scanning the luminous flux;a second lens unit for forming an image on a scanned medium using the luminous flux and having a lens element; anda holding structure connecting the light source to the first lens unit via at least two support members having mutually different linear expansion coefficients,wherein the movement of the image forming point on the scanned medium caused by at least one of thermal deformation of lenses included in the first or second lens units, and thermal refractivity fluctuation of the first or second lens units is compensated by the thermal expansion of the support members, wherein the scanning optical apparatus fulfills the following condition:.alpha.1<.alpha.2.alpha.1: Linear expansion coefficient of the support member A supporting the first lens unit, and.alpha.2: Linear expansion coefficient of the support member B supporting the light source and the support member A.