| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner which makes the distribution of the quantity of light of an image plane uniform and suppresses influence of shading as much as possible, even if the angle of rotation of a polygon scanner varies and a field angle varies. SOLUTION: A cover glass 4 is in a cylindrical shape which has a uniform plate thickness and is arranged around a reflection point P on the mirror surface of the polygon scanner 3. Scanned luminous flux deflected by the polygon scanner 3 is made incident on the cover glass 4, always in its normal direction without depending on the angle of rotation of the polygon scanner 3. The luminous flux made incident on the cover glass 4 is transmitted with uniform transmissivity at any field angle, so that the distribution of the quantity of light of the image plane becomes uniform. |
