| 摘要 |
PROBLEM TO BE SOLVED: To provide a near-infrared ray cut filter comprising an optical multilayer film using an interference effect, which shows a smooth change in the transmittance, is decreased in dependency on an incident angle and has spectral characteristics similar to those of an absorption type color glass filter.SOLUTION: The near-infrared ray cut filter comprises a transparent substrate and an optical multilayer film disposed on at least one major surface of the transparent substrate. The optical multilayer film includes a high refractive index film having a refractive index of 2.0 or more and a low refractive index film having a refractive index of 1.7 or less. The optical multilayer film exhibits the following spectral characteristics. That is, under a perpendicular incident condition, a difference in terms of an absolute value between a wavelength where the transmittance is 80% and a wavelength where the transmittance is 40% in a region between a transmission band and an inhibition band in a near-infrared light side is 20 to 100 nm; and in comparison between the perpendicular incident condition and a 30-degree incident condition, an average wavelength shift amount in terms of an absolute value is 14 nm or less in a region where the transmittance is from 20 to 80% between the transmission band and the inhibition band in near-infrared light side. |
