| CPC G02B 5/282 (2013.01) [G02B 5/208 (2013.01)] | 12 Claims |
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1. An optical filter, comprising:
a substrate; and
a dielectric multilayer film laid on or above at least one major surface of the substrate, the dielectric multilayer film comprising at least two different layers,
wherein:
the dielectric multilayer film comprises a film having a spin density of 5.0×1010/nm·cm2 or larger,
a surface on a dielectric multilayer film side has a nanoindentation hardness of 5.5 GPa or higher when a measurement load is 1 mN,
a maximum transmittance at an incident angle of 0° in a wavelength range of 400 nm to 680 nm is 6% or lower,
a maximum reflectance at an incident angle of 5° in the wavelength range of 400 nm to 680 nm is 20% or lower, and
an average transmittance at an incident angle of 0° in at least one wavelength range having a width of 50 nm included in a wavelength range of 800 nm to 1,580 nm is 90% or higher.
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