MULTI-LAYER ANTI-REFLECTION COATINGS USING INTERMEDIATE LAYERS HAVING MONOTONICALLY GRADED REFRACTIVE INDEX

摘要

An anti-reflection multiple layer coating is formed on a transparent substrate by successive deposition of an inner layer, at least three intermediate layers and an outer layer, the optical thicknesses of the inner and outer layers being approximately lambda /4 and the overall optical thickness of the coating being approximately lambda , where lambda is a reference wavelength within the band of wavelengths over which reflection is to be reduced. The intermediate layers are formed with progressively decreasing refractive indices from the innermost to the outermost intermediate layers, either as a number of separate layers or as a single layer of graded refractive index.