Anti-reflection coating, optical member having it, and optical equipment comprising such optical member

摘要

A anti-reflection coating comprising first to ninth layers laminated in this order on a substrate for having reflectance of 0.2% or less to light in a visible wavelength range of 390-720 nm, the second, fourth, sixth and eighth layers being high-refractive-index layers formed by high-refractive-index materials having refractive indices of 2.21-2.70 to a helium d-line having a wavelength of 587.56 nm; the first, third, fifth and seventh layers being intermediate-refractive-index layers formed by an intermediate-refractive-index material having a refractive index of 1.40 or more and less than 1.55 to the d-line; and the ninth layer being a low-refractive-index layer formed by a low-refractive-index material having a refractive index of 1.35 or more and less than 1.40 to the d-line.

主权项

1. An anti-reflection coating comprising first to ninth layers laminated in this order on a substrate for having reflectance of 0.2% or less to light in a visible wavelength range of 390-720 nm,
said second, fourth, sixth and eighth layers being high-refractive-index layers each formed by a high-refractive-index material having a refractive index of 2.21-2.70 to a helium d-line having a wavelength of 587.56 nm; said first, third, fifth and seventh layers being intermediate-refractive-index layers each formed by an intermediate-refractive-index material having a refractive index of 1.40 or more and less than 1.55 to said d-line; and said ninth layer being a low-refractive-index layer formed by a low-refractive-index material having a refractive index of 1.35 or more and less than 1.40 to said d-line; wherein the refractive index difference between said intermediate-refractive-index layers and said high-refractive-index layers is 0.67-1.30.