| 摘要 |
PROBLEM TO BE SOLVED: To provide an antireflection film exhibiting a performance excellent in wavelength band characteristics and incident angle characteristics on an optical substrate whose refraction index is in a range of 1.43 to 1.65, and an optical system and an optical instrument having the same.SOLUTION: The antireflection film is formed on an optical substrate 101 whose refraction index is a Nsub, and is formed with, in order from the optical substrate side, a first layer 103 whose refraction index is N1 and whose film thickness is D1, a second layer 104 whose refraction index is N2 and whose film thickness is D2, and a third layer 105 that is composed of fine uneven structures, that has a refraction index changing from N3 toward 1.0, and that has a film thickness of D3, to set each parameter appropriately. |
