ANTIREFLECTION COATING AND OPTICAL ELEMENT INCLUDING THE SAME

摘要

Provided is an antireflection coating to be formed on a substrate comprising a first layer, a second layer, a third layer and a fourth layer that are laminated in order from the substrate side to the air side. In the antireflection coating, a refractive index of material of the substrate for the reference wavelength of 550 nm ns, a refractive index of material of the first layer for the reference wavelength of 550 nm n1, a physical film thickness of the first layer d1, a refractive index of material of the fourth layer n4, and a physical film thickness of the fourth layer d4 are appropriately set.

主权项

1. An antireflection coating to be formed on a substrate,
the antireflection coating comprising a first layer, a second layer, a third layer and a fourth layer that are laminated in order from the substrate side to the air side, the antireflection coating satisfying the following conditional expressions:
ns≧1.651.3≦n1≦1.7n1≦ns 1.15≦n4≦1.300.018λ≦nl×d1≦0.125λ0.18λ≦n4×d4≦0.27λ where λ represents a reference wavelength of 550 nm, ns represents a refractive index of material of the substrate for the reference wavelength, n1 represents a refractive index of material of the first layer for the reference wavelength, d1 (nm) represents a physical film thickness of the first layer, n4 represents a refractive index of material of the fourth layer, and d4 (nm) represents a physical film thickness of the fourth layer.