US 12,449,580 B2
Near-infrared cut filter and imaging apparatus
Takahiro Sakagami, Shizuoka (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Jun. 3, 2022, as Appl. No. 17/805,319.
Application 17/805,319 is a continuation of application No. PCT/JP2020/042816, filed on Nov. 17, 2020.
Claims priority of application No. 2019-231753 (JP), filed on Dec. 23, 2019.
Prior Publication US 2022/0299687 A1, Sep. 22, 2022
Int. Cl. G02B 5/28 (2006.01)
CPC G02B 5/281 (2013.01) [G02B 5/28 (2013.01); G02B 5/282 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A near-infrared cut filter, comprising:
a transparent substrate having a first surface and a second surface opposite to each other; and
a dielectric multilayer film positioned on a first surface side of the transparent substrate and configured to reflect light within a wavelength range from 700 nm to 750 nm,
wherein the near-infrared cut filter has a mean transmittance T1 of 20% or less, a mean reflectance R1 of 80% or less, and a mean transmittance T2 of 65% or more, where the mean transmittance T1 is a mean regular transmittance within a wavelength range of 700 nm to 750 nm and is measured when light is incident in a normal direction from a second surface side of the transparent substrate, the mean reflectance R1 is a mean regular reflectance within a wavelength range of 700 nm to 750 nm and is measured when light is incident at an angle of 5° with respect to the normal direction from the second surface side of the transparent substrate, and the mean transmittance T2 is a mean regular transmittance within a wavelength range of 600 nm to 680 nm and is measured when light is incident in the normal direction from the second surface side of the transparent substrate.