Optical filter, ambient light sensor, sensor module and electronic device

Abstract

One object of the present disclosure is to show an optical filter capable of realizing both an excellent visible light transmittance and an excellent near-infrared ray-shielding performance even if an incident angle becomes large. The optical filter of the present disclosure has a base material (i) including a light absorbing layer, and transmits visible light, wherein the light absorbing layer has a maximum absorption in a wavelength range of 750 nm to 1,150 nm, and in a wavelength range of 850 nm to 1,050 nm, an average OD value measured in a direction perpendicular to the optical filter is 2.0 or more, and an average OD value measured at an angle of 60° with respect to the direction perpendicular to the optical filter is 2.0 or more.

1 . An optical filter that includes a base material (i) having a light absorbing layer and transmits visible light,
 wherein the light absorbing layer is a fluorophosphate glass layer or a phosphate glass layer that contains a copper component, and has a maximum absorption in a wavelength range of 750 to 1,150 nm, and   wherein, in a wavelength range of 850 to 1,050 nm, an average OD value measured in a direction perpendicular to the optical filter is 2.0 or more, and an average OD value measured at an angle of 60° with respect to the direction perpendicular to the optical filter is 2.0 or more.   
     
     
         2 . The optical filter according to  claim 1 ,
 wherein, in a wavelength range of 430 to 580 nm, an average value of transmittance measured in the direction perpendicular to the optical filter is 30% or more and 80% or less.   
     
     
         3 . The optical filter according to  claim 1 ,
 wherein, in a wavelength range of 850 to 1,050 nm, an average OD value measured in a direction perpendicular to the base material (i) is 1.0 or more.   
     
     
         4 . The optical filter according to  claim 1 ,
 wherein a dielectric multilayer film is provided on at least one surface of the base material (i).   
     
     
         5 . The optical filter according to  claim 1 ,
 wherein the optical filter is for an ambient light sensor.   
     
     
         6 . An ambient light sensor comprising the optical filter according to  claim 1 . 
     
     
         7 . An ambient light sensor comprising:
 a photoelectric conversion element configured to generate a photocurrent according to light incident on a light receiving surface and measure an illuminance and a color temperature; and   an optical filter that is disposed on the side of the light receiving surface of the photoelectric conversion element,   wherein the optical filter includes a near infrared absorbing layer and a near infrared reflective layer, wherein the near infrared absorbing layer is a fluorophosphate glass layer or a phosphate glass layer that contains a copper component.   
     
     
         8 . The ambient light sensor according to  claim 7 ,
 wherein the near infrared reflective layer is a dielectric multilayer film.   
     
     
         9 . The ambient light sensor according to  claim 7  in which the optical filter has a transmittance that satisfies the following conditions (A) to (C):
 (A) in a wavelength range of 430 to 580 nm, an average value of transmittance measured in a direction perpendicular to the optical filter is 50% or more; 
 (B) in a wavelength range of 800 to 1,000 nm, an average value of transmittance measured in the direction perpendicular to the optical filter is 15% or less; and 
 (C) in a wavelength range of 560 to 800 nm, an absolute value |Xa−Xb| of a difference between a value Xa of a wavelength at which a transmittance measured in the direction perpendicular to the optical filter becomes 50% and a value Xb of a wavelength at which a transmittance measured at an angle of 30° with respect to the direction perpendicular to the optical filter becomes 50% is less than 20 nm. 
 
     
     
         10 . The ambient light sensor according to  claim 7 ,
 wherein the optical filter has a structure in which the near infrared reflective layer and the near infrared absorbing layer are disposed in that order from the side of a light incident surface.   
     
     
         11 . The ambient light sensor according to  claim 7 ,
 wherein the near infrared absorbing layer has a maximum absorption in a wavelength range of 750 to 1,150 nm, and   wherein, in a wavelength range of 850 to 1,050 nm, an average OD value measured in the direction perpendicular to the optical filter is 2.0 or more, and an average OD value measured at an angle of 60° with respect to the direction perpendicular to the optical filter is 2.0 or more.   
     
     
         12 . The ambient light sensor according to  claim 6 , further comprising
 a proximity sensor that includes a light emitting element configured to emit near infrared rays and a second photoelectric conversion element configured to detect near infrared rays.   
     
     
         13 . The ambient light sensor according to  claim 7 , further comprising
 a proximity sensor that includes a light emitting element configured to emit near infrared rays and a second photoelectric conversion element configured to detect near infrared rays.   
     
     
         14 . The optical filter according to  claim 5 , further comprising a light scattering film. 
     
     
         15 . The ambient light sensor according to  claim 6 , further comprising a light scattering film. 
     
     
         16 . The ambient light sensor according to  claim 7 , further comprising a light scattering film. 
     
     
         17 . A sensor module comprising the optical filter according to  claim 1 . 
     
     
         18 . An electronic device comprising the optical filter according to  claim 5 . 
     
     
         19 . An electronic device comprising the ambient light sensor according to  claim 6 . 
     
     
         20 . An electronic device comprising the ambient light sensor according to  claim 7 .