Optical filter used in a microbe inactivation processing device
An optical filter which is used in an inactivation processing device that performs inactivation processing on a processing target microorganism. The optical filter, when discharge light from a light source in which the center wavelength of the discharge light is between 190 nm and 237 nm is incident at an incident angle 0°, transmits at least a portion of the ultraviolet ray equal to or greater than 190 nm and equal to or less than 230 nm and at least a portion of the ultraviolet ray greater than 230 nm and equal to or less than 237 nm, and attenuates the light intensity between 200 and 280 nm not including a wavelength region equal to or greater than 190 nm and equal to or less than 237 nm.
1. An optical filter comprising:
a substrate; and
a film disposed on a surface of the substrate,
wherein for light incident on the optical filter at an incident angle of 0° perpendicular to the surface:
the optical filter is configured to transmit at least a part of the light having a wavelength within a range of not lower than 190 nm and not more than 230 nm,
the optical filter is configured to transmit 40% or more of at least a wavelength of the light within a range of more than 230 nm and not more than 237 nm, and
the optical filter is configured to block the light having a wavelength outside of a wavelength range of greater than 190 nm and less than 237 nm.
2. The optical filter according to claim 1 , wherein
the film includes a dielectric multilayer film having an SiO2 layer and an Al2O3 layer.
3. The optical filter according to claim 2 , wherein
the substrate is composed of a synthetic quartz glass.
4. The optical filter according to claim 1 , wherein
the film includes a dielectric multilayer film having an HfO2 layer and an SiO2 layer.
5. The optical filter according to claim 3 , wherein
the HfO2 layer includes a plurality of HfO2 layers, and
the plurality of HfO2 layers has a total thickness of less than 500 nm.
6. The optical filter according to claim 5 , wherein
the HfO2 layer includes a plurality of HfO2 layers, and
the plurality of HfO2 layers has a total thickness of not less than 100 nm.
7. The optical filter according to claim 4 , wherein
the HfO2 layer includes a plurality of HfO2 layers, and
the plurality of HfO2 layers has a total thickness of not less than 100 nm.
8. The optical filter according to claim 4 , further comprising an AR coating.
9. The optical filter according to claim 4 , wherein
the substrate is composed of a synthetic quartz glass.
10. The optical filter according to claim 1 , further comprising an AR coating.
11. The optical filter according to claim 1 , wherein
the film includes a dielectric multilayer film and the substrate is composed of a synthetic quartz glass.