Antireflection coating film, and optical element, optical system, and optical apparatus having the same

摘要

An antireflection coating film formed on an optical base member includes: a first layer having a refractive index of N1 and a film thickness of D1; a second layer having a refractive index of N2 and a film thickness of D2; and a third layer formed of a fine concavo-convex structure, having a refractive index changing from N3 to 1.0, and a film thickness of D3, wherein the first, second, and third layer are formed in order from the optical base member side having a refractive index of Nsub, and wherein when the refractive indexes Nsub, N1, N2, and N3 are those taken when a wavelength is 550 nm, conditions for Nsub, N1, D1, N2, D2, N3 and D3 are satisfied.

主权项

1. An antireflection coating film formed on an optical base member comprising:
a first layer having a refractive index of N1 and a film thickness of D1; a second layer having a refractive index of N2 and a film thickness of D2; and a third layer formed of a fine concavo-convex structure, having a refractive index changing from N3 to 1.0, and a film thickness of D3, wherein the first, second, and third layer are formed in order from the optical base member side having a refractive index of Nsub, and wherein when the refractive indices Nsub, N1, N2, and N3 are those taken for a light having a wavelength of 550 nm, the following conditions are satisfied;
1.43≦Nsub≦1.651.30≦N1≦1.5022nm≦D1≦45 nm1.42≦N2≦1.5218 nm≦D2≦35 nm1.35≦N3≦1.52180 nm≦D3≦320 nmN1