Imaging lens
AssigneeKantatsu Co., Ltd.
InventorsYoji KUBOTA, Kenichi KUBOTA, Hitoshi HIRANO, Tomohiro YONEZAWA
Life of this patent
Estimating the term…
Abstract
An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are arranged respectively with a space in between. The fifth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The seventh lens is formed in a shape so that a surface thereof on the image plane side and a surface thereof on the object side are aspheric.
Claims18
An imaging lens comprising:
- a first lens having positive refractive power;
- a second lens;
- a third lens;
- a fourth lens;
- a fifth lens;
- a sixth lens;
- and
- a seventh lens, arranged in this order from an object side to an image plane side,
- wherein said first lens, said second lens, said third lens, said fourth lens, said fifth lens, said sixth lens, and said seventh lens are arranged respectively with a space in between,
- said fifth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius, and
- said seventh lens is formed in a shape so that a surface thereof on the image plane side and a surface thereof on the object side are aspheric.
An imaging lens comprising:
- a first lens having positive refractive power;
- a second lens;
- a third lens;
- a fourth lens;
- a fifth lens;
- a sixth lens;
- and
- a seventh lens, arranged in this order from an object side to an image plane side,
- wherein said first lens, said second lens, said third lens, said fourth lens, said fifth lens, said sixth lens, and said seventh lens are arranged respectively with a space in between,
- said seventh lens is formed in a shape so that a surface thereof on the image plane side and a surface thereof on the object side are aspheric,
- said seventh lens is formed in the shape so that the surface thereof on the object side has a positive curvature radius,
- said fifth lens has an Abbe's number νd5, and said third lens is disposed away from the fourth lens by a distance D34 on an optical axis so that the following conditional expressions are satisfied:
- 20<νd5<35,
- 0.05<D34/f<0.2,
- where f is a focal length of a whole lens system.
Dependencies are inferred from the claim text.