| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively provide an imaging lens which is compact, has satisfactorily corrected aberration and high resolution and provides a high-quality image. SOLUTION: The imaging lens is constituted of, in order from an object side, an aperture diaphragm, a first lens which has biconvex shape and has positive refractive power, a second lens, at least, whose image side surface has concave shape and which has negative refractive power, a third lens which has convex meniscus shape on an image side and has positive refractive power, and a fourth lens which has convex meniscus shape on the object side at least near an optical axis and has negative refractive power. Resin material is used for all the lenses, and conditions (1) 0.40<f1/f<0.80, (2) 0.35<f3/f<0.65 and (3) 0.34<¾f4¾/f<0.85 (provided that absolute value shows f4<0) are satisfied, where f: composite focal length of the lens entire system, f1: focal length of the first lens, f3: focal length of the third lens, and f4: focal length of the fourth lens. COPYRIGHT: (C)2009,JPO&INPIT
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