| 摘要 |
An image scanning lens includes, arranged in order from the object side, a first lens element having negative refractive power and a meniscus shape with its convex surface on the object side, a biconvex second lens element and a biconcave third lens element that are cemented together, a stop, a biconcave fourth lens element and a biconvex fifth lens element that are cemented together, and a sixth lens element having negative refractive power and a meniscus shape with its convex surface on the image side. The image scanning lens may include only these six lens elements. The image scanning lens satisfies certain conditions related to the focal lengths of the first lens element, the second and third lens elements together, the entire image scanning lens, radii of curvature of various surfaces, and anomalous dispersion of various lens elements. An image reader with an image pickup device, such as a CCD, uses the image scanning lens.
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