Optical filter

Patent metadata

Field	Value
Publication number	US-12554051-B2
Application number	US-202217663274-A
Country	US
Kind code	B2
Filing date	May 13, 2022
Priority date	Nov 15, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

An optical filter includes: a transparent substrate; and an absorption layer on the transparent substrate, the absorption layer containing at least one dye (X) having a maximum absorption wavelength in 600 to 1000 nm. A laminate of the transparent substrate and the absorption layer satisfies all of the following characteristics (i-2) to (i-4): (i-2) a maximum internal transmittance in 700 to 850 nm is 35% or lower; (i-3) a difference between the maximum internal transmittance and a minimum internal transmittance in 700 to 850 nm is 20% or smaller; and (i-4) OD(A) and OD(B) satisfy the following relationship: OD(A)/OD(B)<0.07 where OD(A) is an average optical density of an internal transmittance in 500 to 600 nm and OD(B) is an average optical density of an internal transmittance in 700 to 850 nm.

First claim

The invention claimed is:

1 . An optical filter comprising:
a transparent substrate; and an absorption layer formed on the transparent substrate and comprising at least one dye having a maximum absorption wavelength in a wavelength range of 750 or longer and shorter than 800 nm, wherein a laminate of the transparent substrate and the absorption layer has a maximum internal transmittance of 35% or lower in a wavelength range of 700 to 850 nm, a difference of 10% or smaller between the maximum internal transmittance and a minimum internal transmittance in the wavelength range of 700 to 850 nm, and OD(A)/OD(B)<0.07 where the OD(A) is an average optical density of an internal transmittance in a wavelength range of 500 to 600 nm, and the OD(B) is an average optical density of an internal transmittance in the wavelength range of 700 to 850 nm, the absorption layer has a thickness of 20 μm or smaller, and the optical filter has an average transmittance of 82% or higher in the wavelength range of 500 to 600 nm.

2 . The optical filter according to claim 1 , wherein the optical filter has an average transmittance of 80% or higher in the wavelength range of 500 to 600 nm, and an average transmittance of 10% or lower in the wavelength range of 700 to 850 nm.

3 . The optical filter according to claim 1 , further comprising:
a first reflectance adjustment film formed on the absorption layer.

4 . The optical filter according to claim 3 , further comprising:
a second reflectance adjustment film formed on a main surface of the transparent substrate on an opposite side with respect to a surface on which the first reflectance adjustment film is formed.

5 . The optical filter according to claim 4 , wherein the second reflectance adjustment film has a thickness of 1.3 μm or smaller.

6 . The optical filter according to claim 5 , wherein the second reflectance adjustment film is a dielectric multilayer film configured to block light in a near ultraviolet range.

7 . The optical filter according to claim 3 , wherein the first reflectance adjustment film has a thickness of 1.3 μm or smaller.

8 . The optical filter according to claim 7 , wherein the first reflectance adjustment film is a dielectric multilayer film configured to block light in a near ultraviolet range.

9 . The optical filter according to claim 1 , wherein the at least one dye includes a compound having a maximum absorption wavelength in a wavelength range of 750 nm or longer and shorter than 800 nm.

10 . The optical filter according to claim 9 , wherein the at least one dye includes a plurality of dyes.

11 . The optical filter according to claim 9 , wherein the compound satisfies an internal transmittance of 10% at a maximum absorption wavelength in a spectral internal transmittance curve that is measured by dissolving the compound in a resin, and E>100−(D/100), where D in nm is the maximum absorption wavelength and E is an average internal transmittance in the wavelength range of 500 to 600 nm.

12 . The optical filter according to claim 9 , wherein the compound is at least one dye selected from the group consisting of a squarylium dye and a cyanine dye.

13 . The optical filter according to claim 1 , wherein the laminate of the transparent substrate and the absorption layer has the difference of 10% or smaller between the maximum internal transmittance and the minimum internal transmittance in the wavelength range of 700 to 850 nm.

14 . An optical filter comprising:
a transparent substrate; an absorption layer on the transparent substrate and comprising at least one dye having a maximum absorption wavelength in a wavelength range of 750 or longer and shorter than 800 nm such that the absorption layer has a thickness in a range of 0.3 to 20 μm; a first reflectance adjustment film formed on the absorption layer and comprising a dielectric multilayer film configured to block light in a near ultraviolet range such that the first reflectance adjustment film has a thickness of 1.3 μm or smaller; and a second reflectance adjustment film formed on a main surface on an opposite side with respect to a surface on which the first reflectance adjustment film is formed, and comprising dielectric multilayer film such that the second reflectance adjustment film has a thickness of 1.3 μm or smaller, wherein a laminate of the transparent substrate and the absorption layer has a maximum internal transmittance of 35% or lower in a wavelength range of 700 to 850 nm, and a difference of 10% or smaller between the maximum internal transmittance and a minimum internal transmittance in the wavelength range of 700 to 850 nm, and the optical filter has an average transmittance of 82% or higher in the wavelength range of 500 to 600 nm.

15 . The optical filter according to claim 14 , wherein the at least one dye includes a compound having a maximum absorption wavelength in a wavelength range of 750 nm or longer and shorter than 800 nm.

16 . The optical filter according to claim 15 , wherein the at least one dye includes a plurality of dyes.

17 . The optical filter according to claim 15 , wherein the compound satisfies an internal transmittance of 10% at a maximum absorption wavelength in a spectral internal transmittance curve that is measured by dissolving the compound in a resin, and E>100−(D/100), where D in nm is the maximum absorption wavelength and E is an average internal transmittance in a wavelength range of 500 to 600 nm.

18 . The optical filter according to claim 15 , wherein the compound is at least one dye selected from the group consisting of a squarylium dye and a cyanine dye.

19 . The optical filter according to claim 14 , wherein the laminate of the transparent substrate and the absorption layer has the difference of 10% or smaller between the maximum internal transmittance and the minimum internal transmittance in the wavelength range of 700 to 850 nm.

Assignees

• Agc Inc

Inventors

• ORITA Yuichiro
• Shiono Kazuhiko
• Nakayama Motoshi
• Shimada Takuro

Classifications

• G06V40/1329

  Protecting the fingerprint sensor against damage caused by the finger · CPC title

• G06V40/1318

  using electro-optical elements or layers, e.g. electroluminescent sensing · CPC title

• G02B5/208

  for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation · CPC title

• C09B67/0084

  Dispersions of dyes · CPC title

• C09B57/00

  Other synthetic dyes of known constitution · CPC title