# US 11,906,764 B2 · Optical filters and image sensors and camera modules and electronic devices

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- Number: US 11,906,764 B2
- Document ID: US11906764B2
- Status: Granted
- Kind: B2
- Application number: 17/224,516
- Filed: 2021-04-07
- Published: 2021-11-04
- Granted: 2024-02-20
- Earliest claimed: 2020-04-29
- Assignees: Samsung Electronics Co., Ltd.; Industry-University Cooperation Foundation Korea Aerospace University
- Applicants: Samsung Electronics Co., Ltd.; Industry-University Cooperation Foundation Korea Aerospace University
- Inventors: Mi Jeong Kim; Jinyoung Hwang; Chung Kun Cho; Hye Ran Kim
- Web page: https://patentgrep.com/patent/US11906764B2

## CPC

- G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation}
- G02B 5/281: {designed for the infrared light}
- G02B 1/002: {made of materials engineered to provide properties not available in nature, e.g. metamaterials}
- G02B 5/008: {Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553)}
- H10F 39/805: {Coatings}
- H10F 39/8053: {Colour filters}
- H10F 39/806: {Optical elements or arrangements associated with the image sensors}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- G02B 2207/101: Nanooptics
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

An optical filter includes a near-infrared absorbing layer including a first material, the first material being configured to absorb light in a first wavelength spectrum belonging to a near-infrared wavelength spectrum. The optical filter includes a compensation layer adjacent to the near-infrared absorbing layer, the compensation layer including a second material different from the first material. The optical filter includes a metamaterial structure spaced apart from the near-infrared absorbing layer via the compensation layer, the metamaterial structure being configured to absorb or reflect light in a second wavelength spectrum at least partially overlapped with the first wavelength spectrum.

## Claims

### Claim 1

An optical filter, comprising:
a near-infrared absorbing layer including a first material, the first material being configured to absorb light in a first wavelength spectrum within a near-infrared wavelength spectrum,
a compensation layer adjacent to the near-infrared absorbing layer, the compensation layer including a second material different from the first material, and
a metamaterial structure spaced apart from the near-infrared absorbing layer via the compensation layer, the metamaterial structure being configured to absorb, reflect, and/or scatter light in a second wavelength spectrum at least partially overlapped with the first wavelength spectrum such that the second wavelength spectrum at least partially overlaps the near-infrared wavelength spectrum.

### Claim 2 (depends on 1)

The optical filter of claim 1, wherein the metamaterial structure is not in direct contact with the near-infrared absorbing layer.

### Claim 3 (depends on 1)

The optical filter of claim 1, wherein
the compensation layer is at a lower portion, an upper portion, or a side portion of the near-infrared absorbing layer, and
the metamaterial structure is embedded in the compensation layer.

### Claim 4 (depends on 1)

The optical filter of claim 1, wherein the compensation layer surrounds the metamaterial structure.

### Claim 5 (depends on 4)

The optical filter of claim 4, wherein the metamaterial structure surrounded by the compensation layer is embedded in the near-infrared absorbing layer.

### Claim 6 (depends on 1)

The optical filter of claim 1, wherein the second material is not configured to absorb light in the first wavelength spectrum.

### Claim 7 (depends on 1)

The optical filter of claim 1, wherein a maximum extinction coefficient (k) in a wavelength spectrum of about 700 nm to about 1200 nm of the second material is less than about 0.01.

### Claim 8 (depends on 1)

The optical filter of claim 1, wherein an average refractive index (n) in a wavelength spectrum of about 700 nm to about 1200 nm of the second material is about 1.4 to about 2.6.

### Claim 9 (depends on 1)

The optical filter of claim 1, wherein the second material comprises an oxide, a nitride, an oxynitride, a halide, a sulfide, a chalcogenide, a semiconductor element, a semiconductor compound, an organic material, or any combination thereof.

### Claim 10 (depends on 1)

The optical filter of claim 1, wherein a thickness of the compensation layer is about 1.2 times to about 20 times as large as a thickness of the metamaterial structure.

### Claim 11 (depends on 1)

The optical filter of claim 1, wherein a thickness ratio of a thickness of the compensation layer to a thickness of the near-infrared absorbing layer is about 1:4 to about 1:50.

### Claim 12 (depends on 1)

The optical filter of claim 1, wherein
a transmission spectrum of the first material includes a first minimum transmission wavelength that is within the first wavelength spectrum,
a transmission spectrum of the metamaterial structure includes a second minimum transmission wavelength that is within the second wavelength spectrum, and
the first minimum transmission wavelength and the second minimum transmission wavelength are both within a wavelength spectrum of about 700 nm to about 990 nm.

### Claim 13 (depends on 12)

The optical filter of claim 12, wherein a difference between the first minimum transmission wavelength and the second minimum transmission wavelength is less than or equal to about 100 nm.

### Claim 14 (depends on 1)

The optical filter of claim 1, wherein a ratio of an average transmittance in the near-infrared wavelength spectrum of the optical filter to an average transmittance in a visible light wavelength spectrum of the optical filter is less than or equal to about 0.07.

### Claim 15 (depends on 1)

The optical filter of claim 1, wherein
an average transmittance in a wavelength spectrum of about 430 nm to 565 nm of the optical filter is greater than about 80%, and
an average transmittance in a wavelength spectrum of about 700 nm to 800 nm or about 890 nm to 990 nm of the optical filter is less than about 10%.

### Claim 16 (depends on 1)

A camera comprising the optical filter of claim 1.

### Claim 17 (depends on 16)

An electronic device comprising the camera of claim 16.

### Claim 18 (depends on 1)

An image sensor, comprising:
a semiconductor substrate including a plurality of photodiodes, and
the optical filter of claim 1 on the semiconductor substrate.

### Claim 19 (depends on 18)

The image sensor of claim 18, further comprising a color filter at a lower portion of the optical filter or an upper portion of the optical filter.

### Claim 20 (depends on 18)

A camera comprising the image sensor of claim 18.

### Claim 21 (depends on 20)

An electronic device comprising the camera of claim 20.