Imaging lens
AssigneesOptical Logic Inc., Kantatsu Co., Ltd.
InventorYoji Kubota
Life of this patent
Estimating the term…
Abstract
An imaging lens includes an aperture stop, a positive first lens with a biconvex shape, a negative second lens; a negative third lens, a positive fourth lens, and a negative fifth lens arranged in this order from an object side. When the whole lens system has a focal length f, focal lengths and Abbe's numbers of the first and the second lenses are f1, νd1, f2, and νd2, focal lengths of the fourth and fifth lenses are f4 and f5, a composite focal length of the first lens L1 and the second lens L2 is f12, and a distance from a surface of the first lens L1 on the object side to a surface of the fifth lens L5 on the image side is Σd, the imaging lens satisfies the following conditional expressions: 0.7<f12/f<1.4 0.2<|f1/f2|<0.6 15<νd1−νd2 0.4<f4/f<1.0 Σd/f<1.2 |f5/f|<1.0
Claims19
An imaging lens, comprising:
- a first lens having positive refractive power;
- a second lens having negative refractive power;
- a third lens having negative refractive power;
- a fourth lens having positive refractive power;
- and
- a fifth lens having negative refractive power in this order from an object side to an image side,
- wherein said first lens is a biconvex lens,
- said second lens has a concave surface facing the object side,
- said third lens is a meniscus lens having a concave surface facing the object side, and
- said fifth lens is a biconcave lens.
An imaging lens, comprising:
- a first lens having positive refractive power;
- a second lens having negative refractive power;
- a third lens having negative refractive power;
- a fourth lens having positive refractive power;
- and
- a fifth lens having negative refractive power in this order from an object side to an image side,
- wherein said first lens is a biconvex lens,
- said second lens has a concave surface facing the object side,
- said third lens is a meniscus lens having a concave surface facing the object side, and
- said fourth lens has a focal length f4 and a whole lens system has a focal length f so that the following conditional expression is satisfied:
- 0.4<f4/f<1.0.
An imaging lens, comprising:
- a first lens having positive refractive power;
- a second lens having negative refractive power;
- a third lens having negative refractive power;
- a fourth lens having positive refractive power;
- and
- a fifth lens having negative refractive power in this order from an object side to an image side,
- wherein said first lens is a biconvex lens,
- said second lens has a concave surface facing the object side,
- said third lens is a meniscus lens having a concave surface facing the object side, and
- said fifth lens has a focal length f5 and a whole lens system has a focal length f so that the following conditional expression is satisfied:
- |f5/f1<1.0.
Dependencies are inferred from the claim text.