Patent ID: 7443611

Claim:
An imaging lens comprising: in order from an object side of the imaging lens, a first lens of a positive lens; a second lens of a negative lens having a concave surface on an image side thereof; a third lens of a positive lens having a concave surface on an object side thereof, wherein both surfaces of the third lens are aspheric; and a fourth lens of a meniscus lens having a convex surface on an object side thereof and near an optical axis, wherein both surfaces of the fourth lens are aspheric, the imaging lens satisfying conditional expressions (1) to (6): 0.3 <|f 1 /f 2 |<0.8 (1) ν dG1 −ν dG2 >25 (2) | A 1|<1.5×10 −5 ×1/° C. (3) | A 2|<1.5×10 −5 ×1/° C. (4) | A 3|>1.5×10 −5 ×1/° C. (5) | A 4|>1.5×10 −5 ×1/° C. (6) wherein f 1 represents a focal length of the first lens, f 2 represents a focal length of the second lens, ν dG1 represents Abbe number of the first lens, ν dG2 represents Abbe number of the second lens, A 1 represents a linear coefficient of expansion of the first lens, A 2 represents a linear coefficient of expansion of the second lens, A 3 represents a linear coefficient of expansion of the third lens, and A 4 represents a linear coefficient of expansion of the fourth lens.