| CPC G02B 5/223 (2013.01) [G02B 5/281 (2013.01)] | 11 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 as an outermost layer, wherein
the substrate comprises a resin film comprising a dye (I) having a maximum absorption wavelength in a wavelength of 690 to 900 nm in dichloromethane, and a resin,
the optical filter transmits visible light and light in at least part of a wavelength of 900 to 1,000 nm, and
the optical filter satisfies all of the following spectroscopic characteristics (i-1) to (i-6):
(i-1) a maximum transmittance T700-900(0deg)MAX in a spectral transmittance curve in a wavelength of 700 to 900 nm at an incident angle of 0° is 7% or lower;
(i-2) a maximum transmittance T700-850(50deg)MAX in a spectral transmittance curve in a wavelength of 700 to 850 nm at an incident angle of 50° is 5% or lower;
(i-3) IR70900-950(0deg)−IR10900-950(0deg) is 20 nm or smaller, where the IR10900-950(0deg) and the IR 70900-950(0deg) are shortest wavelengths at which transmittances are 10% and 70%, respectively, in a spectral transmittance curve in a wavelength of 900 to 950 nm at an incident angle of 0°;
(i-4) IR70850-930(50deg)−IR10850-930(50deg) is 50 nm or smaller, where the IR10850-930(50deg) and the IR70850-930(50deg) are shortest wavelengths at which transmittances are 10% and 70%, respectively, in a spectral transmittance curve in a wavelength of 850 to 930 nm at an incident angle of 50°;
(i-5) an absolute value of a difference between IR50850(0deg) and IR50850(50deg) is 30 nm or smaller, where the IR50850(0deg) and the IR50850(50deg) are shortest wavelengths at which transmittances are 50% in a spectral transmittance curve in a wavelength of 850 nm or longer at incident angles of 0° and 50°, respectively; and
(i-6) an average transmittance T450-600(0deg)AVE in a spectral transmittance curve in a wavelength of 450 to 600 nm at an incident angle of 0° is 60% or higher.
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