Imaging lens
AssigneeKantatsu Co., Ltd.
InventorsYoji KUBOTA, Kenichi KUBOTA, Hitoshi HIRANO, Hisao FUKAYA
Life of this patent
Estimating the term…
Abstract
An imaging lens includes a first lens group and a second lens group, arranged in this order from an object side to an image plane side. The first lens group includes a first lens, a second lens, and a third lens having negative refractive power. The second lens group includes a fourth lens, a fifth lens having negative refractive power, and a sixth lens. The third lens has a concave surface facing the image plane side near an optical axis thereof. The fourth lens has a specific Abbe's number. The fifth lens has a specific Abbe's number.
Claims20
An imaging lens comprising:
- a first lens group;
- and
- a second lens group, arranged in this order from an object side to an image plane side,
- wherein said first lens group includes a first lens, a second lens, and a third lens having negative refractive power,
- said second lens group includes a fourth lens, a fifth lens having negative refractive power, and a sixth lens,
- said third lens has a concave surface facing the image plane side near an optical axis thereof, and
- said fourth lens has an Abbe's number νd4 and said fifth lens has an Abbe's number νd5 so that the following conditional expressions are satisfied:
- 15<νd4<35,
- 40<νd5<75.
An imaging lens comprising:
- a first lens group;
- and
- a second lens group, arranged in this order from an object side to an image plane side,
- wherein said first lens group includes a first lens, a second lens, and a third lens having negative refractive power,
- said second lens group includes a fourth lens, a fifth lens having negative refractive power, and a sixth lens having negative refractive power,
- said fourth lens has a convex surface facing the image plane side near an optical axis thereof,
- said fifth lens has a concave surface facing the image plane side near an optical axis thereof, and
- said fourth lens has an Abbe's number νd4 and said sixth lens has an Abbe's number νd6 so that the following conditional expressions are satisfied:
- 15<νd4<35,
- 40<νd6<75.
Dependencies are inferred from the claim text.