Optical filter, producing method and optical module

• Main Authors: NUMATA, YUDAI, KATSUDA, MASATO, MATSUDA, SHOICHI
• Format: Patent
• Language: Chinese; English
• Published: 21.02.2023
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; SEMICONDUCTOR DEVICES

This optical filter has a back-scattering property, and the linear transmittance thereof to light of at least some wavelengths in the wavelength range of 760-2000 nm is 60% or higher. Where: the azimuth from an incidence plane when the polar angle of the direction of incidence of incident light is 0° is 20°, and the value of a bidirectional reflectance distribution function in the direction where the polar angle is -60° is BRDF (0°; 20°, -60°); the azimuth from an incidence plane when the polar angle of the direction of incidence of incident light is 30° is 20°, and the value of a bidirectional reflectance distribution function in the direction where the polar angle is -60° is BRDF (30°; 20°, -60°); and the azimuth from an incidence plane when the polar angle of the direction of incidence of incident light is 60° is 20°, and the value of a bidirectional reflectance distribution function in the direction where the polar angle is -60° is BRDF (60°; 20°, - 60°), then, for the incident light having at least some