| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an antireflection film which has high antireflection performance with regard to substrates having various refractive indices and which can reduce generation of ghosts or flares, and to provide an optical element and an optical system having the antireflection film.SOLUTION: The antireflection film comprises layers stacked on a substrate having a refractive index ns. The layers are, successively from the substrate side, a first layer, a second layer, a third layer, a fourth layer, a fifth layer, a sixth layer and a seventh layer. Under the conditions of a reference wavelengthλset to 587.6 nm and ns satisfying 1.43≤ns≤2.10, refractive indices n1, n2, n3, n4, n5, n6 and n7 and optical film thicknesses d1 (nm), d2 (nm), d3 (nm), d4 (nm), d5 (nm), d6 (nm) and d7 (nm) of the first, second, third, fourth, fifth, sixth, and seventh layers, respectively, are controlled to satisfy the respective conditions within predetermined ranges.</p> |
