| 摘要 |
The image forming lens comprises a stop and a single lens placed in this order from the object side, wherein if the object-side surface of the single lens having paraxial curvature radii to form biconvex surfaces is referred to as the first surface while the image-side surface is referred to as the second surface, both the first surface and the second surface of said single lens have an aspherical shape, and the focal length f, the distance d 0 along the axis from the stop to the first surface of the single lens, the paraxial curvature radius R 1 of the first surface and the distance L 0 along the axis from the stop to the focal points satisfy the following conditional expressions: <?in-line-formulae description="In-line Formulae" end="lead"?>0.18<d0/f<0.25 (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.60<R1/f<0.85 (2)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>1.40<L0/f<1.55. (3)<?in-line-formulae description="In-line Formulae" end="tail"?>
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