US 12,468,078 B2
Optical filter
Yosuke Sugihara, Tokyo (JP); Yasuyuki Takimoto, Tokyo (JP); Takahiro Mashimo, Tokyo (JP); Atsushi Koyanagi, Tokyo (JP); Naoto Tatsuoka, Tokyo (JP); Masaaki Miyake, Tokyo (JP); and Hideaki Takahoshi, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP); and Optical Coatings Japan, Tokyo (JP)
Filed by AGC Inc., Tokyo (JP); and Optical Coatings Japan, Tokyo (JP)
Filed on Dec. 23, 2021, as Appl. No. 17/645,786.
Claims priority of application No. 2020-217140 (JP), filed on Dec. 25, 2020; and application No. 2021-135902 (JP), filed on Aug. 23, 2021.
Prior Publication US 2022/0206201 A1, Jun. 30, 2022
Int. Cl. G02B 1/115 (2015.01); G02B 5/26 (2006.01); G02B 5/28 (2006.01)
CPC G02B 5/285 (2013.01) [G02B 1/115 (2013.01); G02B 5/26 (2013.01); G02B 5/282 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An optical filter, comprising:
a substrate; and
a dielectric multilayer film formed on at least one major surface of the substrate and comprising at least two films different from each other such that the at least two films includes a film having a spin density of 5.0×1010/(nm·cm2) or higher,
wherein the optical filter satisfies a maximum transmittance T400-680MAX in a wavelength range of 400 nm to 680 nm is 6% or lower and at least one of a maximum reflectance R400-680MAX and an average reflectance R400-680AVE in the wavelength range of 400 nm to 680 nm is 10% or lower, and the optical filter is configured to transmit light in a wavelength range of 1530 nm to 1570 nm, and
wherein the optical filter has a minimum transmittance T1530-1570MIN of 90% or higher in a wavelength range of 1530 nm to 1570 nm.