| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image reading optical system unit which is capable of preventing deterioration in optical performance due to thermal expansion or thermal shrinkage. <P>SOLUTION: The image reading optical system unit comprises: a housing; and a first optical member, a diaphragm, and a second optical member disposed along an optical axis. The first optical member, the diaphragm, and the second optical member are obtained by arraying optical elements on a straight line orthogonal to the optical axis and are provided with plural positioning means. Among the plural positioning means, one positioning means nearest to the center line or on the central axis has a shape to regulate displacement in the longer direction, the others having a shape permitting the displacement in the longer direction. <P>COPYRIGHT: (C)2013,JPO&INPIT |
