Imaging lens and imaging device
An imaging lens is provided with: a first lens with negative power; a second lens with negative power; a third lens with positive power; and a fourth lens with positive power. The cemented fourth lens is formed from an object side lens with negative power and an image side lens with positive power. The thickness of a resin adhesive layer that bonds the object side lens and the image side lens is 20 μm or greater on the optical axis, and when Sg 1 H is the amount of sag in the image side lens surface of the object side lens and Sg 2 H is the amount of sag in the object side lens surface of the image side lens. The bonding operation is easy without damage occurring to the cemented surfaces, with a design that takes into account thickness of the resin adhesive layer; therefore various forms of aberration can be corrected.
1. An imaging lens consisting of:
a first lens having negative power, a second lens having negative power, a third lens having positive power, an aperture, and a fourth lens having positive power arranged in order from an object side toward an image side,
wherein the fourth lens is a cemented lens composed of an object side lens having negative power and an image side lens having positive power, the object side lens and the image side lens each having a cemented surface that is an aspheric surface being convex toward the object side, and
the following conditional expressions (1), (2) and (3) are satisfied:
0.9 ≤Rs/f (1)
R 31≤| R 32| (2)
v 3≤31 (3),
where Rs represents a radius of curvature of the image side lens surface of the object side lens, f represents a focal point distance of an entire lens system, R 31 represents a radius of curvature of the object side lens surface of the third lens, R 32 represents a radius of curvature of an image side lens surface of the third lens, and v 3 represents an Abbe number of the third lens.
2. The imaging lens according to claim 1 , characterized in that the following conditional expression (4) is satisfied:
0.847≤ f≤ 1.248 (4).
3. The imaging lens according to claim 1 , characterized in that the following conditional expression (5) is satisfied:
0.934≤ Rs≤ 1.398 (5).
4. The imaging lens according to claim 1 , wherein
the imaging lens has a half angle of view of 96° or greater.