Patent ID: 7301695
Filing Date: 2007-11-27
Classification: G02B

Abstract:
1. An anti-reflective film of an eight-layer structure formed on a substrate, comprising a plurality of pairs of alternating layers comprising high refractive-index layers and low refractive-index layers having a refractive index lower than a refractive index of the high refractive-index layers, wherein the first, third, fifth, and seventh layers as counted from the substrate are the high refractive-index layers and the second, fourth, sixth, and eighth layers as counted from the substrate are the low refractive-index layers, wherein a designed central wavelength λ 0 is within a wavelength range of 141 nm to 189 nm, and wherein when the first to eighth layers have optical film thicknesses d 1 , d 2 , d 3 , d 4 , d 5 , d 6 , d 7 , and d 8 respectively, the equations of: are satisfied.