ANTI-REFLECTION STRUCTURE AND OPTICAL APPARATUS

摘要

PROBLEM TO BE SOLVED: To give high anti-reflection performance and high mechanical strength to an anti-reflection structure.SOLUTION: The anti-reflection structure includes at least a refractive index gradient layer 2 which is disposed on a substrate 1 and whose refractive index decreases as a distance from the substrate increases, and a homogeneous layer 3 which is disposed on the refractive index gradient layer and whose refractive index is homogeneous. The structure satisfies a condition of nb-na>0.10 where na represents the refractive index of the homogenous layer, and nb represents an effective refractive index on the homogenous layer side of the refractive index gradient layer.