# US 12,181,697 B2 · Optical filter

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- Number: US 12,181,697 B2
- Document ID: US12181697B2
- Status: Granted
- Kind: B2
- Application number: 18/396,795
- Filed: 2023-12-27
- Published: 2024-05-02
- Granted: 2024-12-31
- Earliest claimed: 2021-07-07
- Assignees: AGC Inc.
- Applicants: AGC Inc.
- Inventors: Kazuhiko Shiono; Takashi Nagata
- Web page: https://patentgrep.com/patent/US12181697B2

## CPC

- G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation}
- G02B 5/22: Absorbing filters {(G02B5/201 - G02B5/208 take precedence)}
- G02B 5/28: Interference filters
- G02B 5/281: {designed for the infrared light}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical filter, includes: a substrate, a dielectric multilayer film 1 laid on or above one major surface of the substrate, and a dielectric multilayer film 2 laid on or above the other major surface of the substrate, in which the substrate includes a near infrared ray absorbing glass and a resin film, the resin film includes a resin and a pigment (NIR1), and the optical filter satisfies all of spectral characteristics (i-1) to (i-3), (i-6) to (i-8), and (i-10) to (i-13).

## Claims

### Claim 1

An optical filter, comprising:
a substrate,
a dielectric multilayer film 1 laid on or above one major surface of the substrate, and
a dielectric multilayer film 2 laid on or above the other major surface of the substrate, wherein
the substrate comprises a near infrared ray absorbing glass and a resin film,
the resin film has a thickness of 10 μm or less,
the resin film comprises a resin and a pigment (NIR1), and
the optical filter satisfies all of the following spectral characteristics (i-1) to (i-3), (i-6) to (i-8), and (i-10) to (i-13):
(i-1) in a spectral transmittance curve at an incident angle of 0 degrees, an average transmittance T450-600(0deg)AVE at a wavelength of 450 nm to 600 nm is 80% or more,
(i-2) in a spectral transmittance curve at an incident angle of 50 degrees, an average transmittance T450-600(50deg)AVE at the wavelength of 450 nm to 600 nm is 80% or more,
(i-3) an absolute value of a difference between the average transmittance T450-600(0deg)AVE and the average transmittance T450-600(50deg)AVE is 5% or less,
(i-6) in the spectral transmittance curve at an incident angle of 0 degrees, a maximum transmittance T450-600(0deg)MAX at the wavelength of 450 nm to 600 nm is 90% or more,
(i-7) in the spectral transmittance curve at an incident angle of 0 degrees, a wavelength IR50(0deg) at which a transmittance is 50% is in a range of 610 nm to 650 nm,
(i-8) in the spectral transmittance curve at an incident angle of 50 degrees, a wavelength IR50(50deg) at which a transmittance is 50% is in the range of 610 nm to 650 nm,
(i-10) in the spectral transmittance curve at an incident angle of 0 degrees, a maximum transmittance T1000-1200(0deg)MAX at a wavelength of 1,000 nm to 1,200 nm is 5% or less,
(i-11) in the spectral transmittance curve at an incident angle of 50 degrees, a maximum transmittance T1000-1200(50deg)MAX at the wavelength of 1,000 nm to 1,200 nm is 5% or less,
(i-12) the transmittance T450(0deg)/the maximum transmittance T1000-1200(0deg)MAX≥25, and
(1-13) the transmittance T450(50deg)/the maximum transmittance T1000-1200(50deg)MAX≥10.

### Claim 2 (depends on 1)

The optical filter according to claim 1, further satisfying the following spectral characteristics (i-4) and (i-5):
(i-4) in the spectral transmittance curve at an incident angle of 0 degrees, a transmittance T450(0deg) at a wavelength of 450 nm is 80% or more, and
(i-5) in the spectral transmittance curve at an incident angle of 50 degrees, a transmittance T450(50deg) at the wavelength of 450 nm is 80% or more.

### Claim 3 (depends on 1)

The optical filter according to claim 1, further satisfying the following spectral characteristic (i-9):
(1-9) an absolute value of a difference between the wavelength IR50(0deg) and the wavelength IR50(50deg) is 10 nm or less.

### Claim 4 (depends on 1)

The optical filter according to claim 1, further satisfying the following spectral characteristics (i-14) and (i-15):
(i-14) in the spectral transmittance curve at an incident angle of 0 degrees, a maximum transmittance T750-1000(0deg)MAX at a wavelength of 750 nm to 1,000 nm is 1% or less, and
(i-15) in the spectral transmittance curve at an incident angle of 50 degrees, a maximum transmittance T750-1000(50deg)MAX at the wavelength of 750 nm to 1,000 nm is 1% or less.

### Claim 5 (depends on 1)

The optical filter according to claim 1, wherein the substrate satisfies all of the following spectral characteristics (ii-1) to (ii-7):
(ii-1) an average internal transmittance T450-600AVE at the wavelength of 450 nm to 600 nm is 85% or more,
(ii-2) a maximum internal transmittance T450-600MAX at the wavelength of 450 nm to 600 nm is 92% or more,
(ii-3) an internal transmittance T450 at the wavelength of 450 nm is 82% or more,
(ii-4) a wavelength IR50 at which the internal transmittance is 50% is in a range of 610 nm to 650 nm,
(ii-5) an average internal transmittance T750-1000AVE at a wavelength of 750 nm to 1,000 nm is 1.5% or less,
(ii-6) a maximum internal transmittance T1000-1200MAX at the wavelength of 1,000 nm to 1,200 nm is 5% or less, and
(ii-7) the internal transmittance T450/the maximum internal transmittance T1000-1200MAX≥15.

### Claim 6 (depends on 1)

The optical filter according to claim 1, wherein the substrate further satisfies the following spectral characteristic (ii-8):
(ii-8) a maximum internal transmittance T750-1000MAX at a wavelength of 750 nm to 1,000 nm is 2% or less.

### Claim 7 (depends on 1)

The optical filter according to claim 1, wherein the near infrared ray absorbing glass satisfies all of the following spectral characteristics (iii-1) to (iii-6):
(iii-1) an average internal transmittance T450-600AVE at the wavelength of 450 nm to 600 nm is 90% or more,
(iii-2) an internal transmittance T450 at the wavelength of 450 nm is 92% or more,
(iii-3) a wavelength IR50 at which an internal transmittance is 50% is in a range of 625 nm to 650 nm,
(iii-4) an average internal transmittance T750-1000AVE at a wavelength of 750 nm to 1,000 nm is 2.5% or less,
(iii-5) a maximum internal transmittance T1000-1200MAX at the wavelength of 1,000 nm to 1,200 nm is 5% or less, and
(iii-6) the internal transmittance T450/the maximum internal transmittance T1000-1200MAX≥10.

### Claim 8 (depends on 1)

The optical filter according to claim 1, wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-5):
(iv-1) an average internal transmittance T450-600AVE at the wavelength of 450 nm to 600 nm is 93% or more,
(iv-2) a maximum internal transmittance T450-600MAX at the wavelength of 450 nm to 600 nm is 95% or more,
(iv-3) an internal transmittance T450 at the wavelength of 450 nm is 86% or more,
(iv-4) IR50(L)-IR50(S)≥90 nm where IR50(S) is a shortest wavelength and IR50(L) is a longest wavelength at which an internal transmittance is 50% in a spectral transmittance curve at a wavelength of 650 nm to 900 nm, and
(iv-5) a minimum internal transmittance T700-800MIN at a wavelength of 700 nm to 800 nm is 10% or less.

### Claim 9 (depends on 1)

The optical filter according to claim 1, wherein
the resin film further comprises a pigment (NIR2), and
the pigment (NIR2) has a maximum absorption wavelength in the resin longer than a maximum absorption wavelength of the pigment (NIR1) in the resin by 20 nm to 60 nm.

### Claim 10 (depends on 1)

The optical filter according to claim 1, wherein at least one of the dielectric multilayer film 1 and the dielectric multilayer film 2 satisfies all of the following spectral characteristics (v-1) to (v-5):
(v-1) in a spectral transmittance curve at an incident angle of 0 degrees, a minimum transmittance T450-600(0deg)MIN at the wavelength of 450 nm to 600 nm is 90% or more,
(v-2) in a spectral transmittance curve at an incident angle of 50 degrees, a minimum transmittance T450-600(50deg)MIN at the wavelength of 450 nm to 600 nm is 90% or more,
(v-3) an absolute value of a difference between the minimum transmittance T450-600(0deg)MIN and the minimum transmittance T450-600(50deg)MIN is 5% or less,
(v-4) in the spectral transmittance curve at an incident angle of 0 degrees, an average transmittance T700-1200(0deg)AVE at a wavelength of 700 nm to 1,200 nm is 30% to 75%, and
(v-5) in the spectral transmittance curve at an incident angle of 50 degrees, an average transmittance T700-1200(50deg)AVE at the wavelength of 700 nm to 1,200 nm is 30% to 75%.

### Claim 11 (depends on 1)

The optical filter according to claim 1, wherein at least one of the dielectric multilayer film 1 and the dielectric multilayer film 2 comprises a dielectric thin film having a refractive index of 1.6 to 2.1.

### Claim 12 (depends on 1)

The optical filter according to claim 1, wherein
the resin film comprises a squarylium compound as the pigment (NIR1), and
the resin film further comprises at least one of a squarylium compound and a cyanine compound as a pigment (NIR2) having a maximum absorption wavelength in the resin longer than the maximum absorption wavelength of the pigment (NIR1) in the resin by 20 nm to 60 nm.

### Claim 13 (depends on 1)

The optical filter according to claim 1, wherein the resin film further comprises a pigment (UV) having a maximum absorption wavelength in 370 nm to 440 nm in the resin.

### Claim 14 (depends on 1)

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