| 摘要 |
PROBLEM TO BE SOLVED: To always obtain an excellent image formation performance by an image reading lens, even if the amount of warpage of a line sensor changes owing to an environmental change such as a temperature change. SOLUTION: Object-side lenses E1, E2, and E3 constituting a first group of lenses G1 are held by a first holding member 11, and image-side lenses E4, E5, and E6 constituting a second group of lenses G2 are held by a second holding member 12. A stop 13 is attached to the first member 11 for holding the first group G1. A regulation means 14 is provided as made up of a supporting member having a large coefficient of linear expansion for changing the air interval between the first member 11 and the second member 12, and the first member 11 and the second member 12 are fixed to the regulation means 14 made up of this supporting member. If temperature rises, the supporting member as the regulation means 14 expands, and the first member 11 and the second member 12 fixed to the regulation means 14 move so as to widen or narrow the air interval. COPYRIGHT: (C)2006,JPO&NCIPI
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