Patent ID: 7580205
Filing Date: 2009-08-25
Classification: G02B

Abstract:
1. An imaging lens comprising: in order from an object side of the imaging lens, a first lens having a negative refractive power and having a concave surface directed toward an image side of the imaging lens; a second lens that is one of a planoconcave lens having a flat surface directed toward the object side and a biconcave lens whose surface having a larger absolute value of radius of curvature is directed toward the object side; a third biconvex lens; a stop; a fourth lens whose surface having a smaller absolute value of radius of curvature is directed toward the image side, the fourth lens having a positive refractive power; and a cemented lens having a positive refractive power, the cemented lens including a fifth lens and a sixth lens, the fifth lens having a positive refractive power and having a biconvex shape, the sixth lens having a negative refractive power and having a meniscus shape, the imaging lens satisfying conditional expressions: wherein ν 3 represents an Abbe number of the third lens at the d-line, and wherein N p represents a refractive index of the positive lens constituting the cemented lens at the d-line, N n represents a refractive index of the negative lens constituting the cemented lens at the d-line, ν p represents an Abbe number of the positive lens constituting the cemented lens at the d-line, and ν n represents an Abbe number of the negative lens constituting the cemented lens at the d-line.