| 摘要 |
PROBLEM TO BE SOLVED: To achieve an imaging lens which has good telecentricity on an image side, and which is bright, compact and excellent in performance and suitable for an imaging apparatus using a solid-state imaging element.SOLUTION: The imaging lens comprises three-group and four-lens constitution, where first to fourth lenses are disposed from an object side, an aperture diaphragm is disposed between the first lens and the second lens, and the second lens and the third lens are cemented together. The first lens L1 is a negative meniscus lens with a convex surface directed to the object side. The second lens L2 is a positive lens with a concave surface having strong curvature directed to an image side. The third lens L3 is a negative lens with a concave surface having strong curvature directed to the object side. The fourth lens L4 is a positive lens with a convex surface having strong curvature directed to the image side. F which is focal length of the whole system, f1 which is focal length of the first lens, f23 which is composite focal length of the cemented second and third lenses, satisfy conditions (1) and (2), and N1 which is a refractive index with respect to a d-line of material of the first lens, is more than 1.80. |
