IMAGING LENS

摘要

An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; and a sixth lens having negative refractive power, arranged from an object side to an image plane side. The first lens has an object-side surface and an image plane-side surface having positive curvature radii. The third lens has an object-side surface and an image plane-side surface having positive curvature radii. The fourth lens has an object-side surface and an image plane-side surface having negative curvature radii. The sixth lens is formed so that at least one of an object-side surface and an image plane-side surface is an aspherical surface and has at least one inflexion point. The first lens and the second lens have a specific composite focal length.

主权项

1. An imaging lens comprising:
a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; and a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side, wherein said first lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side have positive curvature radii, said third lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side have positive curvature radii, said fourth lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side have negative curvature radii, said sixth lens is formed in a shape so that at least one of a surface thereof on the object side and a surface thereof on the image plane side is an aspherical surface and has at least one inflexion point at a location off an optical axis thereof, and said first lens and said second lens have a composite focal length f12 so that the following conditional expression is satisfied:
0.8