Patent ID: 7365916
Filing Date: 2008-04-29
Classification: G02B

Abstract:
1. An aspherical lens comprising: a substrate member, a member having a different composition from the substrate member and being formed on the substrate member, a boundary surface between the substrate member and the member having the different composition being formed by a first aspherical surface, a surface of the member having the different composition opposite to the boundary surface being formed by a second aspherical surface, a refractive index of a medium of the substrate member at d-line in which λ=587.56 nm is higher than a refractive index of a medium of the member having the different composition at d-line in which λ=587.56 nm, a thickness of a center portion of the substrate member is larger than that of the member having the different composition, and the following conditional expressions being satisfied: where Na denotes the refractive index of the medium of the substrate member at d-line in which λ=587.56 nm, and Nb denotes the refractive index of the medium of the member having the different composition at d-line in which λ=587.56 nm, PV