Abstract: An imaging lens includes a first lens group having positive refractive power; a second lens group having positive refractive power; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens having negative refractive power and a seventh lens having negative refractive power. The first lens, the second lens, the third lens, and the seventh lens have specific Abbe's numbers. The first lens and the second lens have specific focal lengths.

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 having positive refractive power, a second lens having positive refractive power, and a third lens. The second lens group includes a fourth lens, a fifth lens having negative refractive power, and a sixth lens. The sixth lens has a concave surface facing the object side near an optical axis thereof.

Abstract: An imaging lens includes a first lens group having positive refractive power; and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power. The second lens group includes a fourth lens having negative refractive power, a fifth lens having negative refractive power, and a sixth lens having positive refractive power. The first lens group has a specific focal length, and the first to third lenses have specific Abbe's numbers so that the specific conditional expressions are satisfied.

Abstract: An imaging lens includes a first lens group having positive refractive power; a second lens group having positive refractive power; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens, and a third lens. The second lens group includes a fourth lens having positive refractive power and a fifth lens having negative refractive power. The third lens group includes a sixth lens and a seventh lens having negative refractive power. The seventh lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side have positive curvature radii. The surface of the seventh lens on the image plane side is formed in an aspheric shape having at least one inflexion point.

Abstract: An imaging lens includes a first lens having negative refractive power; a second lens having positive refractive power; a third lens having positive refractive power; and a fourth lens, arranged in this order from an object side to an image plane side. The second lens is arranged to face the third lens. The first lens has a focal length f1 and the fourth lens has an Abbe's number ?d4 so that the specific conditional expressions are satisfied.

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 having positive refractive power, a second lens having positive refractive power and at least one aspheric surface, and a third lens having two aspheric surfaces, arranged with a space in between. The second lens group includes a fourth lens having two aspheric surfaces, a fifth lens having negative refractive power and two aspheric surfaces, and a sixth lens having two aspheric surfaces, arranged with a space in between. The third lens is arranged away from the fourth lens by a specific distance, and the fifth lens and the sixth lens have a specific composite focal length, so that specific conditional expressions are satisfied.

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 having positive refractive power, a second lens having positive refractive power, and a third lens. The second lens group includes a fourth lens having positive refractive power, a fifth lens, and a sixth lens having negative refractive power. The fifth lens has a specific Abbe's number.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens; a fifth lens; and a sixth lens, arranged in this order from an object side to an image plane side. The fifth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The fifth lens and the sixth lens have a specific composite focal length. The first lens is disposed away from the second lens by a specific distance on an optical axis thereof. The second lens is disposed away from the third lens by a specific distance.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having negative refractive power; a fourth lens; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side. The fourth lens and the fifth lens have a composite focal length f45, and the third lens has an Abbe's number ?d3 so that the following conditional expressions are satisfied: 0<f45, 40<?d3<75.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; and a sixth lens having negative refractive power, arranged from an object side to an image plane side. The first lens has an object-side surface and an image plane-side surface having positive curvature radii. The third lens has an object-side surface and an image plane-side surface having positive curvature radii. The fourth lens has an object-side surface and an image plane-side surface having negative curvature radii. The sixth lens is formed so that at least one of an object-side surface and an image plane-side surface is an aspherical surface and has at least one inflexion point. The first lens and the second lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens group having positive refractive power and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having negative refractive power, and a third lens. The second lens group includes a front side lens group having negative refractive power and a rear side lens group having positive refractive power. The front side lens group includes a fourth lens and a fifth lens. The rear side lens group includes a sixth lens and a seventh lens. The first lens group is arranged to be away from the second lens group by a specific distance on an optical axis thereof. The first to third lenses have specific Abbe's numbers.

Abstract: An imaging lens includes a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having negative refractive power, and a third lens having positive refractive power. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens having negative refractive power and a seventh lens.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens; a fourth lens having negative refractive power; a fifth lens having positive refractive power; and a sixth lens, arranged in this order from an object side to an image plane side. The first lens is formed so that a surface thereof on the object side has a positive curvature radius. The sixth lens is formed so that a surface thereof on the object side and a surface thereof on the image plane side have positive curvature radii. Each of the first to sixth lenses has an Abbe's number within a specific range.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens; a fourth lens having negative refractive power; a fifth lens having positive refractive power; and a sixth lens, arranged in this order from an object side to an image plane side. The first lens is formed so that a surface thereof on the object side has a positive curvature radius. The sixth lens is formed so that a surface thereof on the object side and a surface thereof on the image plane side have positive curvature radii. Each of the first to sixth lenses has an Abbe's number within a specific range.

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.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; and a fifth lens, arranged from an object side to an image plane side. The first lens is formed such that a curvature radius of a surface on the object side is positive. The third lens is formed such that a curvature radius of a surface on the object side is positive. The fourth lens is formed such that a surface on the object side and a surface on the image plane side are aspheric. The fifth lens is formed such that a surface on the object side and a surface on the image plane side are aspheric, and a curvature radius of the surface thereof on the image plane side is positive near an optical axis thereof. The first lens and the third lens have specific focal lengths.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; and a fifth lens, arranged from an object side to an image plane side. The first lens is formed in a shape so that a curvature radius of a surface on the object side is positive. The third lens is formed such that a curvature radius of a surface on the object side is positive. The fourth lens is formed such that a surface on the object side and a surface on the image plane side are aspheric. The fifth lens is formed such that a surface on the object side and a surface on the image plane side are aspheric, and a curvature radius of the surface on the image plane side is positive near an optical axis thereof. The fourth lens and the fifth lens have specific Abbe's numbers.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; and a fourth and a fifth lens having negative refractive power. The first lens is formed so that a curvature radius of an object-side surface is positive and the second lens is formed so that a curvature radius of an object-side surface and a curvature radius of an image plane-side surface are positive. The third lens is formed so that a curvature radius of an object-side surface is positive, and the fifth lens is formed so that a curvature radius of an object-side surface and a curvature radius of an image plane-side surface are both positive. An Abbe's number from the first and the third to the fifth lens is greater than 45, and an Abbe's number of the second lens is less than 35.

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, ?d1, f2, and ?d2, 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 ?d, the imaging lens satisfies the following conditional expressions: 0.7<f12/f<1.4 0.2<|f1/f2|<0.6 15<?d1??d2 0.4<f4/f<1.0 ?d/f<1.2 |f5/f|<1.

Abstract: An imaging lens includes, in this order from an object side, an aperture stop ST, a positive first lens L1, a negative second lens L2 having a meniscus shape that directs a convex surface on the object side near an optical axis, a positive third lens L3, a positive fourth lens L4 having a meniscus shape that directs a concave surface on the object side near an optical axis, and a negative fifth lens L5 having a meniscus shape that directs a convex surface on the object side near an optical axis.