# US 2018/0027196 A1 · High dynamic range image sensor with virtual high-low sensitivity pixels

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- Number: US 2018/0027196 A1
- Document ID: US20180027196A1
- Status: Published application
- Kind: A1
- Application number: 15/215,139
- Filed: 2016-07-20
- Published: 2018-01-25
- Earliest claimed: 2016-07-20
- Assignees: OmniVision Technologies, Inc.
- Applicants: Omnivision Technologies, Inc.
- Inventors: Dajiang Yang; Gang Chen; Oray Orkun Cellek; Xin Wang; Chen-Wei Lu; Duli Mao; Dyson H. Tai
- Web page: https://patentgrep.com/patent/US20180027196A1

## CPC

- H04N 25/585: with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes
- H04N 25/134: {based on three different wavelength filter elements}
- H04N 25/778: comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/803: {Pixels having integrated switching, control, storage or amplification elements}
- H10F 39/8053: {Colour filters}
- H10F 39/8063: {Microlenses}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An image sensor includes a plurality of photodetectors that are identically sized and fabricated in semiconductor material with identical semiconductor processing conditions. The photodetectors are organized into virtual high-low sensitivity groupings, each including a first photodetector and a second photodetector. A plurality of attenuators is disposed over the semiconductor material. Each one of the plurality of attenuators is disposed along an optical path between a microlens and the first photodetector of each virtual high-low sensitivity grouping such that all incident light directed into the first photodetector is directed through a respective one of the plurality of attenuators. There is no attenuator along a second optical path between a microlens and the second photodetector of each virtual high-low sensitivity grouping such that all the incident light directed into the second photodetector is not directed through one of the plurality of attenuators.

## Claims

### Claim 1

An image sensor, comprising:
a plurality of photodetectors arranged in semiconductor material, wherein each one of the plurality of photodetectors is identically sized and is fabricated in the semiconductor material with identical semiconductor processing conditions, wherein the plurality of photodetectors are organized into virtual high-low sensitivity groupings including a first photodetector and a second photodetector;
an array of microlenses disposed over the semiconductor material, wherein each one of the microlenses is disposed over a respective one of the photodetectors, wherein a first microlens of the array of microlenses is disposed over the first photodetector, and wherein a second microlens of the array of microlenses is disposed over the second photodetector; and
a plurality of attenuators disposed over the semiconductor material, wherein each one of the plurality of attenuators is disposed along a first optical path between the first microlens and the first photodetector of each virtual high-low sensitivity grouping such that all incident light directed into the first photodetector is directed through a respective one of the plurality of attenuators, wherein there is an absence of one of the plurality of attenuators along a second optical path between the second microlens and the second photodetector of each virtual high-low sensitivity grouping such that all the incident light directed into the second photodetector is not directed through one of the plurality of attenuators.

### Claim 2 (depends on 1)

The image sensor of claim 1, wherein the first and second photodetectors comprise photodiodes disposed in the semiconductor material.

### Claim 3 (depends on 2)

The image sensor of claim 2 wherein a full well capacity of the first photodetector is substantially equal to a full well capacity of the second photodetector.

### Claim 4 (depends on 1)

The image sensor of claim 1, wherein the first and second photodetectors comprise single photon avalanche diodes disposed in the semiconductor material.

### Claim 5 (depends on 1)

The image sensor of claim 1, wherein the plurality of photodetectors is disposed proximate to a front side of the semiconductor material, wherein the plurality of attenuators are disposed proximate to a back side of the semiconductor material, and wherein the incident light is directed through the back side of the semiconductor material to the plurality of photodetectors.

### Claim 6 (depends on 1)

The image sensor of claim 1, wherein the plurality of attenuators are comprised of a semi-transparent material having a transmittance of less than 100%.

### Claim 7 (depends on 1)

The image sensor of claim 1, wherein semi-transparent material has a transmittance of 10%-20%.

### Claim 8 (depends on 1)

The image sensor of claim 1, further comprising a transparent oxide layer disposed over the semiconductor material, wherein the incident light directed into the second photodetector along the second optical path is directed through the transparent oxide layer.

### Claim 9 (depends on 1)

The image sensor of claim 1, wherein the first photodetector of each virtual high-low sensitivity grouping is a virtual low sensitivity photodetector a high dynamic range pixel of the image sensor, and wherein the second photodetector of each virtual high-low sensitivity grouping is a virtual high light sensitivity photodetector of the high dynamic range pixel of the image sensor.

### Claim 10 (depends on 1)

The image sensor of claim 1, wherein the first photodetector and the second photodetector of each virtual high-low sensitivity grouping are adjacent in the semiconductor material of a pixel array.

### Claim 11 (depends on 1)

The image sensor of claim 1, further comprising a color filter array disposed over the semiconductor material between the array of microlenses and the plurality of photodetectors in the semiconductor material, wherein the color filter array includes a plurality of color filters.

### Claim 12 (depends on 11)

The image sensor of claim 11, wherein a first one of the plurality of color filters is disposed over the first photodetector, and a second one of the plurality of color filters is disposed over the second photodetector, wherein the first and second color filters are both the same color.

### Claim 13

An imaging system, comprising:
a pixel array including a plurality of photodetectors arranged in semiconductor material, wherein each one of the plurality of photodetectors is identically sized and is fabricated in the semiconductor material with identical semiconductor processing conditions, wherein the plurality of photodetectors are organized into virtual high-low sensitivity groupings including a first photodetector and a second photodetector;
an array of microlenses disposed over the semiconductor material, wherein each one of the microlenses is disposed over a respective one of the photodetectors, wherein a first microlens of the array of microlenses is disposed over the first photodetector, and wherein a second microlens of the array of microlenses is disposed over the second photodetector;
a plurality of attenuators disposed over the semiconductor material, wherein each one of the plurality of attenuators is disposed along a first optical path between the first microlens and the first photodetector of each virtual high-low sensitivity grouping such that all incident light directed into the first photodetector is directed through a respective one of the plurality of attenuators, wherein there is an absence of one of the plurality of attenuators along a second optical path between the second microlens and the second photodetector of each virtual high-low sensitivity grouping such that all the incident light directed into the second photodetector is not directed through one of the plurality of attenuators;
control circuitry coupled to the pixel array to control operation of the pixel array; and
readout circuitry coupled to the pixel array to readout image data from the pixel array.

### Claim 14 (depends on 13)

The imaging system of claim 13, further comprising function circuitry coupled to the readout circuitry to store the image data readout from the pixel array.

### Claim 15 (depends on 13)

The imaging system of claim 13, wherein the first and second photodetectors comprise photodiodes disposed in the semiconductor material.

### Claim 16 (depends on 15)

The imaging system of claim 15, wherein a full well capacity of the first photodetector is substantially equal to a full well capacity of the second photodetector.

### Claim 17 (depends on 13)

The imaging system of claim 13, wherein the first and second photodetectors comprise single photon avalanche diodes disposed in the semiconductor material.

### Claim 18 (depends on 13)

The imaging system of claim 13, wherein the plurality of photodetectors is disposed proximate to a front side of the semiconductor material, wherein the plurality of attenuators are disposed proximate to a back side of the semiconductor material, and wherein the incident light is directed through the back side of the semiconductor material to the plurality of photodetectors.

### Claim 19 (depends on 13)

The imaging system of claim 13, wherein the plurality of attenuators are comprised of a semi-transparent material having a transmittance of 10%-20%.

### Claim 20 (depends on 13)

The imaging system of claim 13, further comprising a color filter array disposed over the semiconductor material between the array of microlenses and the plurality of photodetectors in the semiconductor material, wherein the color filter array includes a plurality of color filters, wherein a first one of the plurality of color filters is disposed over the first photodetector, and a second one of the plurality of color filters is disposed over the second photodetector, wherein the first and second color filters are both the same color.