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US 2015/0177488 A1Published application
Imaging lens
AssigneesOptical Logic Inc., Kantatsu Co., Ltd.
InventorsYoji KUBOTA, Kenichi KUBOTA, Hitoshi HIRANO, Tomohiro YONEZAWA
Life of this patent
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Abstract
An imaging lens includes a first lens having negative refractive power; a second lens having positive refractive power; a third lens; and a fourth lens arranged in the order from an object side to an image plane side. The first lens has an image plane-side surface having a positive curvature radius. The first lens has a specific focal length to satisfy a specific conditional expression.
Claims15
An imaging lens comprising:
- a first lens having negative refractive power;
- a second lens having positive refractive power;
- a third lens;
- and
- a fourth lens, arranged in this order from an object side to an image plane side,
- wherein said first lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius, and
- said first lens has a focal length f1 so that the following conditional expression is satisfied:
- −75<f1/f<−5.0
- where f is a focal length of a whole lens system.
6 more elements
Dependencies are inferred from the claim text.