| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner in which the curvatures of an image plane in a main scanning direction and subscanning direction are excellently corrected and the stability of a light spot is realized while excellently keeping the conjugating function and the constant-speeding function, ghost light appearing on a plane to be scanned due to reflection light occurring on a lens face or between lenses is reduced, and the freedom of the scanning lens layout is improved. SOLUTION: In the optical scanner having: a light source 1; a deflection means 6 which deflects a light beam emitted from the light source and a scanning; and imaging optical system 7 which guides the light beam deflected with the deflection means onto a plane to be scanned 8a, the scanning and imaging optical system 7 is composed of at least two scanning lenses L1 and L2, the scanning lens L1 which is located at a position nearest the deflection means has a positive refractive power in the main scanning direction, the refractive power in the subscanning direction is zero or approximately zero, the scanning lens L2, which is located at a position nearest the plane to be scanned has a positive refractive power both in the main scanning and subscanning directions, and the incident side plane in the subscanning direction of the scanning lens nearest the plane to be scanned is formed in a convex plane facing toward the deflection means. COPYRIGHT: (C)2005,JPO&NCIPI
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