Patent ID: 8368786

Claim:
An image pickup lens comprising: at least one lens block comprising a lens substrate being a parallel flat plate, and a lens portion or lens portions with positive power, formed on at least one of an object-side surface and an image-side surface of the lens substrate, wherein the lens portion or lens portions comprise an energy-curable resin material which is different from a material of the lens substrate, at least one lens portion with positive power among the lens portion or lens portions has a dimension change rate caused by water absorption, the dimension change rate being larger than a dimension change rate caused by water absorption of the lens substrate, and satisfies the following conditional expression (1): 0.0 ≦dn ≦150×10 −5 (1) where dn is a difference (dn 2 −dn 1 ) between a refractive index dn 1 of the energy-curable resin material measured by keeping the energy-curable resin material in an absolute dry condition at 95° C. for three days and a refractive index dn 2 of the energy-curable resin material measured by keeping the energy-curable resin material at 60° C. and 90% RH for six days.