Abstract: A light scanning device having a light source being electrically ON/OFF controlled, deflection member such as a polygon mirror for deflecting light emitted from the light source to perform scanning operation, a first lens for correcting scanning speed of light deflected by the deflection member on a scanning surface, a second lens for correcting astigmatism of the first lens and/or for compensating tilt of the surface of the polygon mirror, a base plate for separately mounting thereon the first and second lenses with predetermined positional relations, and a housing case for mounting thereon the light source, the deflection member and the base plate with predetermined positional relations. The first and second lenses are seated on the base plate in such a fashion that they satisfy the positional relations with other optical components when the base plate is installed on the housing case.

Abstract: Structure and method for mirror installation in an optical device such as a laser beam scanning device. An installation reference surface and a support surface are formed to be faced to but spaced apart from each other. The mirror is installed between the above two surfaces in such a manner that the reflection surface of the mirror contacts the installation reference surface. An elastic element is inserted and press-fitted between the rear surface of the mirror and the support surface so as to push the mirror against the installation reference surface. Thus, the mirror is stably held between the installation reference surface and the support surface with accurately positioning the reflecting surface of the mirror.

Abstract: A lens unit having a hollow holder and a lens member coupled in the hollow holder in which the lens member has an outer surrounding wall portion integrally formed with the lens member, the outer surrounding wall portion extending along an axis of the lens member, and an outer surface of the outer surrounding wall portion being coupled with an inner wall surface of the hollow holder, whereby the lens member can be prevented from falling or rolling when it is installed in the hollow holder.

Abstract: Installing of an optical component on a housing case. One side of the optical component to be installed is abutted to a reference surface formed on the housing case for positional regulation thereof. A heat-fusible protrusion is formed on the housing case at the position which is opposed to the reference surface and has a vertical length enough to be beyond the top surface of the optical component seated on the housing case. Heat is applied to at least a part of the fusible protrusion to be fused onto the optical component with abutting the one side of the optical component to the reference surface. The fused portion is let to be hardened for regulating the position of the other end of the optical component, whereby the optical component is fixed onto the housing case with regulating the posture thereof in the direction crossing to the reference surface.