| 主权项 |
1. An imaging lens substantially consisting of six lenses consisting of, in order from an object side:
a first lens having a biconvex shape; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power and having a concave surface toward the object side; and a sixth lens having a negative refractive power and having a concave surface toward the object side, wherein the condition expression below is satisfied:
−1<f×P45<0 (4), where f is a focal length of the entire system, and P45 is a refractive power of an air lens formed by an image-side surface of the fourth lens and an object-side surface of the fifth lens, where the refractive power of the air lens is calculated according to the equation (P) below:P45=1-Nd4L4r+Nd5-1L5f-(1-Nd4)×(Nd5-1)×D9L4r×L5f(P) where Nd4 is a refractive index with respect to the d-line of the fourth lens, Nd5 is a refractive index with respect to the d-line of the fifth lens, L4r is a paraxial radius of curvature of an image-side surface of the fourth lens, L5f is a paraxial radius of curvature of an object-side surface of the fifth lens, and D9 is an air space along the optical axis between the fourth lens and the fifth lens. |
