| 摘要 |
PURPOSE:To make a scanning surface flat and to prevent uneven scanning pitch by paralleling the light refracted by a lens on a hologram desk and focusing and refocusing the parallel light by a concave mirror and a f-theta lens respectively. CONSTITUTION:A hologram desk 1 is rotated around the axis of rotation by a motor 3 through a rotary shaft 2. A hologram lens 6 is constituted so as to make the laser light refracted by the lens 6 parallel beam. Refracted light 14a is penetrated in a concave mirror 17 and reflected by the mirror 17 as the focused laser light flux 14b. The center 18 of the radius of curvature of the concave mirror 17 is positioned on a plane including the center light 14' of a laser light flux 14 and the axis 4 of rotation of the disk 1. After focusing, the focused laser light flux 14b is penetrated into an f-theta lens 20 as the light flux dispersed at a point 19 after focusing and focused again on a scanning surface 1. Consequently the influences of the eccentricity of the hologram 1 and the shearing in the direction of rotational axis can be reduced. |
