Optical filter, detection device, and optical laminate
AssigneeNitto Denko Corporation
InventorsMasato KATSUDA, Yudai NUMATA, Shoichi MATSUDA
Life of this patent
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Abstract
In an optical filter, a BRDF (bidirectional reflectance distribution function) in a case where visible light with a wavelength of 550 nm enters at an incident angle of 0° is 0.1 [1/sr] or greater at angles which are not less than −30° and not more than −5° and angles which are not less than 5° and not more than 30°; and, in a BTDF (bidirectional transmittance distribution function) in a case where infrared light with a wavelength of 850 nm enters at an incident angle of 0°, (a value at −1°)/(a value at −10°) and (a value at 1°)/(a value at 10°) are 30 or smaller.
Claims14
An optical filter wherein,
- a BRDF (bidirectional reflectance distribution function) in a case where visible light with a wavelength of 550 nm enters at an incident angle of 0° is 0.1 [1/sr] or greater at angles which are not less than −30° and not more than −5° and angles which are not less than 5° and not more than 30°;
- and,
- in a BTDF (bidirectional transmittance distribution function) in a case where infrared light with a wavelength of 850 nm enters at an incident angle of 0°, (a value at −1°)/(a value at −10°) and (a value at 1°)/(a value at 10°) are 30 or smaller;
- the optical filter comprising:
- an optical layer that causes backward scatter of the visible light and permits linear transmission of the infrared light;
- and
- a scattering layer that causes forward scatter of the infrared light, the scattering layer being disposed on the optical layer directly or via another layer.
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Dependencies are inferred from the claim text.