发明名称 Imaging lens, image reader using the lens, and imaging apparatus using the image reader
摘要 An imaging lens comprises a first, a second, a third, and a fourth lens group from an object toward an image. The first lens group includes a first lens that is a convex meniscus lens with a convex surface on the object side. The second lens group includes a second lens having a positive refractive power, and a third lens bonded to the second lens and having a negative refractive power. The third lens group includes a fourth lens having a negative refractive power, and a fifth lens bonded to the fourth lens and having a positive refractive power. The fourth lens group includes a sixth lens having a positive refractive power. The imaging lens satisfies the condition <?in-line-formulae description="In-line Formulae" end="lead"?>0.10<D/f<0.19<?in-line-formulae description="In-line Formulae" end="tail"?> where D denotes a sum of an air gap between the first lens and the second lens and an air gap between the fifth lens and the sixth lens, and f denotes a focal length of the entirety of the imaging lens with respect to an e-ray.
申请公布号 US7180642(B2) 申请公布日期 2007.02.20
申请号 US20020139325 申请日期 2002.05.07
申请人 RICOH COMPANY, LTD. 发明人 MIYATAKE NAOKI
分类号 H04N1/46;G02B1/11;G02B13/24 主分类号 H04N1/46
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