| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system capable of reducing ghosts in a wide range without decreasing transmittance performance by using an antireflection film having scratch resistance and good antireflection performance.SOLUTION: The optical system includes a first optical surface where a first antireflection film is formed, and a second optical surface where a second antireflection film is formed. The first and second antireflection films have different reflection characteristics from each other. The first antireflection film includes a first layer containing hollow silica, while the second antireflection film includes a second layer containing hollow silica. The first and second layers each have a refractive index of 1.3 or less with respect to light at a wavelength from 400 nm to 700 nm. |
