Patent ID: 6894848

Claim:
An image scanning lens comprising, in order from the object side with no intervening lens element: a first lens component having positive refractive power and a meniscus shape with its convex surface on the object side and including a first lens element having positive refractive power and a meniscus shape with its convex surface on the object side; a second lens component having a biconcave shape and including a second lens element having a biconcave shape; a third lens component having a biconvex shape and including a third lens element having a biconvex shape; a fourth lens component having negative refractive power and a concave surface on the object side and including a fourth lens element having negative refractive power and a concave surface on the object side; wherein the following conditions are satisfied: θ gd >−2.083·10 −3 ·ν d +1.366 for said first lens element, θ gd <−2.083·10 −3 ·ν d +1.364 for at least one of said second lens element and said fourth lens element, where ν d is the Abbe number at the d-line (587.56 nm) of the lens material of the lens element being considered, and θ gd =(N g −N d )/(N F −N C ) where N g is the refractive index at the g-line (λ=435.83 nm) of the lens material of the lens element being considered, N d is the refractive index at the d-line (λ=587.56 nm) of the lens material of the lens element being considered, N F is the refractive index at the F-line (λ=486.13 nm) of the lens material of the lens element being considered, and N C is the refractive index at the C-line (λ=656.27 nm) of the lens material of the lens element being considered.