| 摘要 |
PROBLEM TO BE SOLVED: To highly precisely read information to be read and to miniaturize and simplify the device itself. SOLUTION: A telecentric lens 10 sets scanning width in the main scanning direction on an original 6 constant by making respective main light beams parallel on the light beams for information reading R, which ate deflected and scanned in the main scanning direction by a polygon mirror 2. Furthermore, a focus position is changed in accordance with the movement of a moving mirror 9 by a pair of Fresnel lenses (a Fresnel lens face 6A (positive lens) and a Fresnel lens face 6B (negative lens)) formed in an original stand 6G, and the focus position is always set on the original 6. |
