IMAGING LENS, IMAGING UNIT, AND OPTICAL DEVICE

摘要

It is possible to obtain an imaging lens system having a small size for easy carrying and a preferable image performance corresponding to a high number of pixels. The imaging lens system is intended for forming an optical image of an object on a light reception surface of a solid imaging element. The imaging lens system includes an aperture diaphragm and three lens elements arranged in this order from the object side: a first lens element as a both-side aspherical lens having a positive power and a convex surface at the image side, a second lens element as a both-side aspherical meniscus lens having a negative power and a concave shape at the object side, and a third lens element as a both-side aspherical meniscus lens having a positive power and a convex shape at the object side. The lens elements satisfy the following conditions: 1.5 < ||fd/f2d|| < 2.3 0.5 < ||fd/f3d| < 1.1 -2.2 < (R21 + r22)/(r21 - r22) < -1.3 2.1 < (R31 + r32)/(r31 - r32) < -1.7