Abstract: An imaging lens may be a retrofocus type imaging optical system including, in order from an object side, a first lens group, an aperture and a second lens group. The first lens group may include, from the object side, a meniscus as a first lens in which a convex surface is formed on the object side, and a meniscus lens as a second lens in which a convex surface is formed on the object side. The second lens group may include a convex lens as a third lens, a biconvex lens as a fourth lens, a biconvex lens as a fifth lens and a sixth lens, and the fifth lens and the sixth lens may be joined to each other. The imaging lens may be constructed with 6 elements and 5 groups including the first lens group and the second lens group.

Abstract: An imaging lens unit includes a resin lens barrel and a plurality of lenses incorporated in the lens barrel. The lens barrel has a lens barrel body and a box-shaped part. A plurality of lens receiving parts are arranged at predetermined intervals in a circumferential direction of the lens barrel body and protrude from an inner peripheral surface of the lens barrel body. The fourth lens is fixed to the lens barrel in a state of being engaged with the plurality of lens receiving parts.

Abstract: An imaging lens includes a front group having negative power, an aperture stop, and a rear group having positive power, in order from an object side. In the front group, a first lens surface has a convex shape toward the object side. In the rear group, a second lens surface has a convex shape toward the object side, a third lens surface has a convex shape toward the image side, and the third lens surface has an infrared ray cut coat. A curvature radius of the second lens surface is represented by Rr, a curvature radius of the third lens surface is represented by Re, a distance from the second lens surface to the third lens surface on an optical axis is represented by Da, and the following condition is satisfied: 1.6<(Rr+|Re |)/Da<2.3.

Abstract: An imaging lens may be a retrofocus type imaging optical system including, in order from an object side, a first lens group, an aperture and a second lens group. The first lens group may include, from the object side, a meniscus as a first lens in which a convex surface is formed on the object side, and a meniscus lens as a second lens in which a convex surface is formed on the object side. The second lens group may include a convex lens as a third lens, a biconvex lens as a fourth lens, a biconvex lens as a fifth lens and a sixth lens, and the fifth lens and the sixth lens may be joined to each other. The imaging lens may be constructed with 6 elements and 5 groups including the first lens group and the second lens group.

Abstract: An imaging lens unit with a plurality of lenses may be incorporated in a lens barrel of resin, the lenses may include, in order from the object side, a first lens group, an aperture, and a second lens group. The first lens group may include, from the object side, a meniscus lens as a first lens with a convex surface on the object side, and a meniscus lens as a second lens with a convex surface on the object side. The second lens group may include, from the object side, a convex lens as a third lens, a biconvex lens as a fourth lens, a biconvex lens as a fifth lens, and a concave lens as a sixth lens. The first lens to the sixth lens may be incorporated in the lens barrel with a reference position between the third lens and the fourth lens.