# US 8,570,464 B2 · Optical filter, solid-state imaging element having the filter, and imaging apparatus

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- Number: US 8,570,464 B2
- Document ID: US8570464B2
- Status: Granted
- Kind: B2
- Application number: 12/824,067
- Filed: 2010-06-25
- Published: 2010-12-30
- Granted: 2013-10-29
- Earliest claimed: 2009-06-30
- Assignees: Canon Kabushiki Kaisha
- Applicants: Tomohiro Yamada; Ryo Kuroda
- Inventors: Tomohiro Yamada; Ryo Kuroda
- Web page: https://patentgrep.com/patent/US8570464B2

## CPC

- G02B 5/1809: {with pitch less than or comparable to the wavelength}
- G02B 5/203: {having holographic or diffractive elements (diffraction gratings per se G02B5/18; holographic elements per se G02B5/32; generating the spectrum using diffraction elements G01J3/18)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical filter includes a substrate, and a periodic structure in which a plurality of members formed of silicon are periodically arranged on a surface of the substrate. The filter selectively transmits light of a first wavelength included in light incident on the periodic structure in the direction of the substrate. The members are two-dimensionally arranged with a period of 400 nm to 500 nm. The dimension of the members in the direction parallel to the surface is of 120 nm to 160 nm. A local maximum value of the transmission spectrum of the first wavelength is within the range of 400 nm to 500 nm.

## Claims

### Claim 1

A transmissive optical filter comprising:
a substrate; and
a first region in which a plurality of first members formed of silicon are periodically arranged on a surface of the substrate,
wherein the first members are two-dimensionally arranged on the first region with a period of 400 nm to 500 nm, a dimension of each of the first members in a direction parallel to the surface of the substrate is 120 nm to 160 nm, and the first region has a local maximum value of a transmission spectrum within 400 nm to 500 nm.

### Claim 2 (depends on 1)

The transmissive optical filter according to claim 1, further comprising a second region in which a plurality of second members are two-dimensionally arranged with a period of 400 nm to 500 nm, a dimension of each of the second members in the direction parallel to the surface of the substrate being of 200 nm to 240 nm,
wherein the second region has a local maximum value of the transmission spectrum within 600 nm to 700 nm, and is different from the first region.

### Claim 3 (depends on 2)

The transmissive optical filter according to claim 2, further comprising a third region in which a plurality of third members are two-dimensionally arranged with a period of 400 nm to 500 nm, a dimension of each of the third members in the direction parallel to the surface of the substrate being of 160 nm to 200 nm, and
wherein the third region has a local maximum value of the transmission spectrum within 500 nm to 600 nm, and is different from the first region and the second region.

### Claim 4 (depends on 1)

The transmissive optical filter according to claim 1, further comprising an a second region in which a plurality of second members are two-dimensionally arranged with a period of 400 nm to 500 nm, a dimension of the second members in the direction parallel to the surface of the substrate being of 160 nm to 200 nm, and wherein the second region has a local maximum value of the transmission spectrum within 500 nm to 600 nm, and is different from the first region.

### Claim 5 (depends on 1)

The transmissive optical filter according to claim 1, wherein a thickness of the first members is 50 nm to 150 nm.

### Claim 6 (depends on 1)

The transmissive optical filter according to claim 1, wherein the substrate is formed of dielectric material.

### Claim 7 (depends on 6)

The transmissive optical filter according to claim 6, wherein the first region is covered with a dielectric material.

### Claim 8 (depends on 7)

The transmissive optical filter according to claim 7, wherein the permittivity of the dielectric material of which the substrate is formed is equal to the permittivity of the dielectric material that covers the first region.

### Claim 9 (depends on 7)

The transmissive optical filter according to claim 7, wherein a periodic structure is formed on the dielectric material covering the first region.

### Claim 10 (depends on 6)

The transmissive optical filter according to claim 6, wherein the dielectric material is silicon dioxide.

### Claim 11 (depends on 1)

A solid-state imaging element comprising the transmissive optical filter according to claim 1.

### Claim 12 (depends on 11)

An imaging apparatus comprising the solid-state imaging element according to claim 11.

### Claim 13 (depends on 3)

The transmissive optical filter according to claim 3, wherein the first region, the second region and the third region are arranged in a Bayer arrangement.

### Claim 14 (depends on 1)

The transmissive optical filter according to claim 1, wherein, the local maximum value of the transmission spectrum is 80% or more.

### Claim 15 (depends on 1)

The transmissive optical filter according to claim 1, wherein the first region has a local minimum value of the transmission spectrum within 500 nm to 700 nm, and the local minimum value of the transmission spectrum is 40% or less.