| 摘要 |
PROBLEM TO BE SOLVED: To provide an antireflection film having a low reflectivity in a wide wavelength range. SOLUTION: The antireflection film 4 is disposed on the surface of a light transmissive substrate 5 by successively laminating a 1st layer 1 having a refractive index of 1.70-1.80 and an optical thickness of 0.21λ to 0.29λ, a 2nd layer 2 having a refractive index >=2.20 and an optical thickness of 0.41λ to 0.54λ and a 3rd layer 3 having a refractive index of 1.44-1.49 and an optical thickness of 0.22λ to 0.27λ from the substrate 5 side toward the air layer 6 side. |
