Patent ID: 8840257
Filing Date: 2014-09-23
Classification: G02B

Abstract:
1. An antireflection film formed on an optical surface of an optical member, and configured to prevent a reflection of a light beam incident on the optical surface, the antireflection film comprising: a first wavelength region in which a distribution width by wavelength conversion is 50 nm or more and 200 nm or less; and a second wavelength region in which a distribution width by wavelength conversion is 180 nm or less, as a spectral reflectance property when alight beam is incident on the optical surface at an incident angle of 0 degree, wherein the first wavelength region includes: a first bottom part provided in a wavelength range of 400 nm or more; and a second bottom part being at a wavelength side longer than the first bottom part and provided adjacent to the first bottom part, wherein the second wavelength region is provided continuously from the second bottom part at a wavelength side longer than second bottom part, wherein in the spectral reflectance property, a maximum reflectance P by shifting a wavelength range where the reflectance is a specific value or less, to a wavelength side longer than the second wavelength region, the reflectance in the second wavelength region is decreased, and the reflectance in the first wavelength region is increased so that a luminance difference is small between a ghost in the first wavelength region and a ghost in the second wavelength region.