# US 9,521,381 B2 · RGBC color filter array patterns to minimize color aliasing

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- Number: US 9,521,381 B2
- Document ID: US9521381B2
- Status: Granted
- Kind: B2
- Application number: 15/098,151
- Filed: 2016-04-13
- Published: 2016-08-11
- Granted: 2016-12-13
- Earliest claimed: 2014-11-25
- Assignees: OmniVision Technologies, Inc.
- Applicants: Omnivision Technologies, Inc.
- Inventors: Raymond Wu; Jizhang Shan; Chin Poh Pang
- Web page: https://patentgrep.com/patent/US9521381B2

## CPC

- H04N 25/135: {based on four or more different wavelength filter elements}
- G06T 3/4015: Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
- H04N 25/133: including elements passing panchromatic light, e.g. filters passing white light
- H04N 25/70: SSIS architectures; Circuits associated therewith
- H10F 39/182: {Colour image sensors}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/8053: {Colour filters}
- H10F 39/8063: {Microlenses}
- H04N 2209/047: using multispectral pick-up elements
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

Implementations of a color filter array comprising a plurality of tiled minimal repeating units. Each minimal repeating unit includes at least a first set of filters comprising three or more color filters, the first set including at least one color filter with a first spectral photoresponse, at least one color filter with a second spectral photoresponse, and at least one color filter with a third spectral photoresponse; and a second set of filters comprising one or more broadband filters positioned among the color filters of the first set, wherein each of the one or more broadband filters has a fourth spectral photoresponse with a broader spectrum than any of the first, second, and third spectral photoresponses, and wherein the individual filters of the second set have a smaller area than any of the individual filters in the first set. Other implementations are disclosed and claimed.

## Claims

### Claim 1

A color filter array comprising:
a plurality of tiled minimal repeating units, each minimal repeating unit including at least:
a first set of filters comprising three or more color filters, the first set including at least one color filter with a first spectral photoresponse, at least one color filter with a second spectral photoresponse, and at least one color filter with a third spectral photoresponse, and
a second set of filters comprising one or more broadband filters positioned among the color filters of the first set, wherein each of the one or more broadband filters has a fourth spectral photoresponse with a broader spectrum than any of the first, second, and third spectral photoresponses, and wherein the individual filters of the second set have a smaller area than any of the individual filters in the first set;
wherein the first set includes four rectangular color filters arranged to form a quadrilateral annulus and the second set includes a single broadband filter positioned in the interior of the quadrilateral annulus, the quadrilateral annulus being a shape that results when the area of one quadrilateral is subtracted from the interior of a larger quadrilateral that has the same shape and the same center.

### Claim 2 (depends on 1)

The color filter array of claim 1 wherein one of the rectangular color filters has the first spectral photoresponse, two of the rectangular color filters have the second spectral photoresponse, and one of the rectangular color filters has the third spectral photoresponse.

### Claim 3 (depends on 2)

The color filter array of claim 2 wherein the first spectral photoresponse is red (R), the second spectral photoresponse is green (G), the third spectral photoresponse is blue (B), and the fourth spectral photoresponse is panchromatic (P).

### Claim 4 (depends on 1)

The color filter array of claim 1 wherein the first photoresponse is cyan (C), the second photoresponse is magenta (M), the third photoresponse is yellow (Y), and the fourth photoresponse is panchromatic (P).

### Claim 5 (depends on 4)

The color filter array of claim 4 wherein two of the rectangular color filters are yellow, one is cyan, and one is magenta.

### Claim 6

An image sensor comprising:
a pixel array including a plurality of individual pixels;
a color filter array positioned over the pixel array such that each individual pixel in the pixel array is optically coupled to a corresponding filter of the color filter array, the color filter array comprising a plurality of tiled minimal repeating units, each minimal repeating unit including at least:
a first set of filters comprising three or more color filters, the first set including at least one color filter with a first spectral photoresponse, at least one color filter with a second spectral photoresponse, and at least one color filter with a third spectral photoresponse, and
a second set of filters comprising one or more broadband filters positioned among the color filters of the first set, wherein each of the one or more broadband filters has a fourth spectral photoresponse with a broader spectrum than any of the first, second, and third spectral photoresponses, wherein the individual filters of the second set have a smaller area than any of the individual filters in the first set,
wherein the first set includes four rectangular color filters arranged to form a quadrilateral annulus and the second set includes a single broadband filter positioned in the interior of the quadrilateral annulus, the quadrilateral annulus being a shape that results when the area of one quadrilateral is subtracted from the interior of a larger quadrilateral that has the same shape and the same center;
readout circuitry coupled to the pixel array to read out signals from the individual pixels; and
function logic coupled to the readout circuitry to process the signals read from the individual pixels.

### Claim 7 (depends on 6)

The image sensor of claim 6 wherein the size of each filter substantially matches the size of its corresponding pixel.

### Claim 8 (depends on 6)

The image sensor of claim 6 wherein the size of each filter is different than the size of its corresponding pixel.

### Claim 9 (depends on 6)

The image sensor of claim 6 wherein one of the rectangular color filters has the first spectral photoresponse, two of the rectangular color filters have the second spectral photoresponse, and one of the rectangular color filters has the third spectral photoresponse.

### Claim 10 (depends on 9)

The image sensor of claim 9 wherein the first spectral photoresponse is red (R), the second spectral photoresponse is green (G), the third spectral photoresponse is blue (B), and the fourth spectral photoresponse is panchromatic (P).

### Claim 11 (depends on 6)

The image sensor of claim 6 wherein the first photoresponse is cyan (C), the second photoresponse is magenta (M), the third photoresponse is yellow (Y), and the fourth photoresponse is panchromatic (P).

### Claim 12 (depends on 11)

The image sensor of claim 11 wherein two of the rectangular color filters are yellow, one is cyan, and one is magenta.