Light beam scanning apparatus

摘要

A light-beam scanning apparatus for conducting a light scanning on a scanning surface (304) by diffracting an incident light from a light source (310) by means of a diffraction grating of a rotatable hologram (302), and diffracting, by means of a fixed plate (303), the diffracted light to be used in a scanning conducted by a rotation of said rotatable hologram (302); the light-beam scanning apparatus being characterized in that the rate of variation of a direction cosine of an object wave determined in a scanning direction of said fixed plate (303) is configured to be different from a rate of variation of a direction cosine of the object wave determined in a cross scanning direction, and focal distances of a light incident on said rotatable hologram (302) are configured to be different in the scanning direction and the cross scanning direction.