| CPC H04N 23/55 (2023.01) [G02F 1/155 (2013.01); G02F 1/157 (2013.01)] | 27 Claims |
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1. An optical apparatus comprising:
a photodetector; and
a light modulating element comprising a plurality of compounds light absorption characteristics of which change with external simulation,
wherein the plurality of compounds are compounds having different absorption wavelengths,
wherein the light modulating element has a variable transmittance VT(λ) obtained by combining light absorption characteristics of the plurality of compounds,
wherein NWDMax<NWDMaxFP is satisfied,
where NWDMax is a maximum value of ratios between a reference light source and a contrast light source and ratios of a signal intensity ratio of a transmitted light for each detection light wavelength region incident on the photodetector between a transmission state and a light attenuation state of the light modulating element (the reference light source/the contrast light source or the contrast light source/the reference light source), and
NWDMaxFP is NWDMax in a concentration ratio of the plurality of compounds in which wavelength flatness TF of the VT(λ) in the detection light wavelength region is a minimum value TFFP, and
wherein the variable transmittance VT(λ) is expressed by formula:
VT(λ)=10−LΣΔεm(λ)Cm
where Δεm(λ) is an absorbance coefficient change of a compound m, where m is 1 to a total number of compounds,
Cm is a concentration of the compound m in the light attenuation state, and
L is an optical path length [m] of the light modulating element.
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