# US 12,181,696 B2 · Optical filter and imaging device

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- Number: US 12,181,696 B2
- Document ID: US12181696B2
- Status: Granted
- Kind: B2
- Application number: 17/193,151
- Filed: 2021-03-05
- Published: 2021-06-24
- Granted: 2024-12-31
- Earliest claimed: 2018-09-12
- Assignees: AGC Inc.
- Applicants: AGC Inc.
- Inventors: Kazuhiko Shiono; Motoshi Nakayama; Tatsuo Yokote; Aya Ito
- Web page: https://patentgrep.com/patent/US12181696B2

## CPC

- G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation}
- H10F 39/806: {Optical elements or arrangements associated with the image sensors}
- C09B 57/007: {Squaraine dyes}
- C09B 67/0063: {of organic pigments with only macromolecular substances}
- G02B 1/04: made of organic materials, e.g. plastics (G02B1/08 takes precedence)
- G02B 5/223: {containing organic substances, e.g. dyes, inks or pigments}
- H10F 39/805: {Coatings}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- C09B: ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES {, e.g. PIGMENTS}; MORDANTS; LAKES (fermentation or enzyme using processes to synthesise a desired chemical compound C12P)

## Abstract

An optical filter includes: a resin substrate having a thickness of 20 μm or more and 110 μm or less; an absorption layer having a thickness of 0.25 μm or more and 12 μm or less and being disposed on at least one principal surface of the resin substrate; and dielectric multilayer films disposed as an outermost layer on both principal surfaces of the resin substrate. At least one of the dielectric multilayer films is a near-infrared reflection layer. The resin substrate includes a first transparent resin having a glass transition temperature of 170° C. or more and having specific optical properties. The absorption layer includes a near-infrared absorbing dye (A) and a second transparent resin having a glass transition temperature of 170° C. or more, and the near-infrared absorbing dye (A) satisfies specific optical properties in relation to the second transparent resin.

## Claims

### Claim 1

An optical filter comprising:
a resin substrate having a thickness of 20 μm or more and 110 μm or less;
an absorption layer having a thickness of 0.25 μm or more and 12 μm or less and being disposed on at least one principal surface of the resin substrate; and
dielectric multilayer films disposed as an outermost layer on both principal surfaces of the resin substrate, wherein:
at least one of the dielectric multilayer films is a near-infrared reflection layer;
the resin substrate comprises, as a main component, a first transparent resin having a glass transition temperature of 170° C. or more, the first transparent resin having, when a thickness thereof is 100 μm, in a spectral transmittance curve over a wavelength range of 350 nm to 1,100 nm, an average internal transmittance in a wavelength range of 350 nm to 450 nm being 95% or more, a minimum internal transmittance in a wavelength range of 400 nm to 450 nm being 97% or more, and a wavelength at which an internal transmittance becomes 90% in a wavelength range of 500 nm or less being 350 nm or less;
the first transparent resin comprises at least one resin selected from a polyimide resin and a polycarbonate resin;
the absorption layer comprises a near-infrared absorbing dye (A) and a second transparent resin having a glass transition temperature of 170° C. or more, and the near-infrared absorbing dye (A) satisfies the following (ii-1) and (ii-2) in relation to the second transparent resin:
(ii-1) in a spectral transmittance curve over a wavelength range of 400 nm to 800 nm as measured in a state of the near-infrared absorbing dye (A) being contained in the second transparent resin, a maximum absorption wavelength λmax(A)TR is within a wavelength range of 680 nm to 745 nm; and
(ii-2) in a spectral transmittance curve over a wavelength range of 350 nm to 1,100 nm when the near-infrared dye (A) is incorporated into the second transparent resin and the internal transmittance at the maximum absorption wavelength λmax(A)TR is adjusted to 1%, both an average internal transmittance T435-500ave(A)TR for light in a wavelength range of 435 nm to 500 nm and an average internal transmittance T500-600ave(A)TR for light in a wavelength range of 500 nm to 600 nm are 94% or more;
the second transparent resin is a polyimide resin; and
an absolute value of a difference between an average transmittance of the optical filter in a range of 380 nm to 425 nm at an incident angle of 0° and an average transmittance of the optical filter in a range of 380 nm to 425 nm at an incident angle of 30° is 3% or less.

### Claim 2 (depends on 1)

The optical filter according to claim 1, wherein the polycarbonate resin has a glass transition temperature of 200° C. or more, and the first transparent resin has, when the thickness thereof is 100 μm, in a spectral transmittance curve over a wavelength range of 350 nm to 1,100 nm, the average internal transmittance in a wavelength range of 350 nm to 450 nm being 98% or more, the minimum internal transmittance in a wavelength range of 400 nm to 450 nm being 98% or more, and the wavelength at which the internal transmittance becomes 90% in a wavelength range of 500 nm or less being 340 nm or less.

### Claim 3 (depends on 1)

The optical filter according to claim 1, wherein the absorption layer has a thickness of 5 μm or less and contains from 5 to 20 parts by mass of the near-infrared absorbing dye per 100 parts by mass of the second transparent resin.

### Claim 4 (depends on 1)

The optical filter according to claim 1, wherein the near-infrared absorbing dye (A) comprises a squarylium dye.

### Claim 5 (depends on 4)

The optical filter according to claim 4, wherein the squarylium dye is a compound represented by the following formula (I) or (II):
wherein symbols in formula (I) are as follows:
each of R24 and R26 independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl or alkoxy group with a carbon number of 1 to 20, an acyloxy group with a carbon number of 1 to 10, an aryl group with a carbon number of 6 to 11, an alaryl group with a carbon number of 7 to 18 which may have a substituent and may have an oxygen atom between carbon atoms, —NR27R28 (wherein each of R27 and R28 independently represents a hydrogen atom, an alkyl group with a carbon number of 1 to 20, —C(═O)—R29 (wherein R29 is a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with a carbon number of 1 to 25 which may have a substituent and may contain, between carbon atoms, an unsaturated bond, an oxygen atom or a saturated or unsaturated ring structure), —NHR30, or —SO2—R30 (wherein each R30 represents a hydrocarbon group with a carbon number of 1 to 25 in which one or more hydrogen atoms may be substituted by a halogen atom, a hydroxyl group, a carboxy group, a sulfo group or a cyano group and which may contain, between carbon atoms, an unsaturated bond, an oxygen atom or a saturated or unsaturated ring structure)), or a group represented by the following formula(S) (wherein R41 and R42 independently represent a hydrogen atom, a halogen atom, or an alkyl or alkoxy group with a carbon number of 1 to 10, and k is 2 or 3):
R21 and R22, R22 and R25, and R21 and R23 may combine with each other to form, respectively, a heterocyclic ring A, a heterocyclic ring B, and a heterocyclic ring C, together with a nitrogen atom, each ring having 5 or 6 ring members;
R21 and R22, when forming heterocyclic ring A, represent, as a divalent group —Q— formed by bonding R21 and R22, an alkylene or alkyleneoxy group in which a hydrogen atom may be substituted by an alkyl group with a carbon number of 1 to 6, an aryl group with a carbon number of 6 to 10, or an acyloxy group with a carbon number of 1 to 10 which may have a substituent;
R22 and R25, when forming heterocyclic ring B, and R21 and R23, when forming heterocyclic ring C, represent, as divalent groups —X1-Y1— and —X2-Y2— (in which a side bonded to nitrogen is X1 and X2 ) formed by bonding R22 and R25, and R21 and R23, respectively, groups in which each of X1 and X2 is a group represented by the following formula (1x) or (2x) and each of Y1 and Y2 is a group represented by any one selected from the following formulae (1y) to (5y), in a case where each of X1 and X2 is a group represented by the following formula (2x), each of Y1 and Y2 may be a single bond, and in this case, the group may have an oxygen atom between carbon atoms:
each of four Z in formula (1x) independently represents a hydrogen atom, a hydroxyl group, an alkyl or alkoxy group with a carbon number of 1 to 6, or —NR38R39 (wherein each of R38 and R39 independently represents a hydrogen atom or an alkyl group with a carbon number of 1 to 20), each of R31 to R36 independently represents a hydrogen atom, an alkyl group with a carbon number of 1 to 6, or an aryl group with a carbon number of 6 to 10, and R37 represents an alkyl group with a carbon number of 1 to 6 or an aryl group with a carbon number of 6 to 10;
R27, R28, R29, R31 to R37, R21 to R23 when not forming a heterocyclic ring, and R25 may combine with any other member among these to form a 5-or 6-membered ring, and R31 and R36, and R31 and R37 may be bonded directly;
each of R21, R22, R23 and R25 when not forming a heterocyclic ring independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl or alkoxy group with a carbon number of 1 to 20, an acyloxy group with a carbon number of 1 to 10, an aryl with a carbon number of 6 to 11, or an alaryl group with a carbon number of 7 to 18 which may have a substituent and may have an oxygen atom between carbon atoms,
wherein symbols in formula (II) are as follows:
each of rings Z is independently a 5-or 6-membered ring having from 0 to 3 heteroatoms in the ring, and a hydrogen atom contained in ring Z may be substituted;
R1 and R2, R2 and R3, and R1 and a carbon atom or heteroatom constituting ring Z may combine with each other to form, respectively, a heterocyclic ring A1, a heterocyclic ring B1, and a heterocyclic ring C1, together with a nitrogen atom, and in this case, a hydrogen atom contained in the heterocyclic ring A1, heterocyclic ring B1 and heterocyclic ring Cl may be substituted; each of R1 and R2 when not forming a heterocyclic ring independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group which may contain, between carbon atoms, an unsaturated bond, a heteroatom, or a saturated or unsaturated ring structure and may have a substituent; and each of R4 and R3 when not forming a heterocyclic ring independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group which may contain a heteroatom between carbon atoms and may have a substituent.

### Claim 6 (depends on 1)

The optical filter according to claim 1, wherein the optical filter has the absorption layer on both principal surfaces of the resin substrate, and both absorption layers have a thickness of 1.5 μm or less.

### Claim 7 (depends on 1)

The optical filter according to claim 1, wherein an absorption layer -attached resin substrate obtained by disposing the absorption layer on at least one principal surface of the resin substrate has, in a spectral transmittance curve over a wavelength range of 350 nm to 1,100 nm, an average internal transmittance in a wavelength range of 435 nm to 480 nm being 90.5% or more, an average internal transmittance in a wavelength range of 500 nm to 600 nm being 90.5% or more, a wavelength at which an internal transmittance becomes 20% in a wavelength range of 600 nm to 740 nm being within a wavelength range of 650 nm to 685 nm, and an average internal transmittance in a wavelength range of 700 nm to 730 nm being 3% or less.

### Claim 8 (depends on 1)

The optical filter according to claim 1, wherein the absorption layer further comprises an ultraviolet absorbing dye (U) having, in a spectral transmittance curve over a wavelength range of 350 nm to 1,100 nm as measured in a state of being dissolved in dichloromethane, a maximum absorption wavelength λmax(U)DCM being within a wavelength range of 380 nm to 420 nm.

### Claim 9 (depends on 8)

The optical filter according to claim 8, wherein the ultraviolet absorbing dye (U) comprises a merocyanine dye.

### Claim 10 (depends on 1)

The optical filter according to claim 1, satisfying the following requirements:
(I-1) at an incident angle of 0°, an average transmittance of light in a wavelength range of 435 nm to 480 nm is 86% or more and an average transmittance of light in a wavelength range of 500 nm to 600 nm is 89% or more;
(I-2) at an incident angle of 30°, an average transmittance of light in a wavelength range of 435 nm to 480 nm is 85% or more and an average transmittance of light in a wavelength range of 500 nm to 600 nm is 89% or more;
(I-4) an absolute value of a difference between an average transmittance in a range of 615 nm to 725 nm at an incident angle of 0° and an average transmittance in a range of 615 nm to 725 nm at an incident angle of 30° is 3% or less; and
(I-5) in a transmittance of light at an incident angle of 0°, a wavelength at which the transmittance becomes 20% is present in a wavelength range of 650 nm to 685 nm.

### Claim 11 (depends on 1)

An imaging device comprising the optical filter according to claim 1.

### Claim 12 (depends on 1)

The optical filter according to claim 1, wherein the first transparent resin comprises a polyimide resin.