Multi-resolution pixel architecture with shared floating diffusion nodes

Patent metadata

Field	Value
Publication number	US-2016353034-A1
Application number	US-201514723233-A
Country	US
Kind code	A1
Filing date	May 27, 2015
Priority date	May 27, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

An image sensor may include an array of image photodiodes formed in rows and columns. The array of image photodiodes may include a region of photodiodes arranged in three adjacent rows and three adjacent columns of the array. The region of photodiodes may include four non-adjacent photodiodes, each of which generates charge in response to the same color of light. The four non-adjacent photodiodes may be coupled to a shared floating diffusion node. Each of the four non-adjacent photodiodes may transfer generated charge to the shared floating diffusion node. The charges from each of the four non-adjacent photodiodes may be summed at the shared floating diffusion node and read out as a summed signal or may be individually transferred to the shared floating diffusion node and read out individually.

First claim

What is claimed is:

1 . An imaging system, comprising:
an array of photodiodes arranged in rows and columns, wherein the array comprises a three-photodiode-by-three-photodiode region that includes a set of four non-adjacent photodiodes; a color filter array, wherein the color filter array comprises a set of four color filter elements formed over the set of four non-adjacent photodiodes, wherein each color filter element in the set of four color filter elements is configured to transmit light of a given wavelength band; and a shared floating diffusion node, wherein a pair of the photodiodes in the set of four non-adjacent photodiodes is formed in a common row of the array and is coupled to the shared floating diffusion node.

2 . The imaging system defined in claim 1 , wherein each of the photodiodes in the set of four non-adjacent photodiodes is coupled to the shared floating diffusion node.

3 . The imaging system defined in claim 2 , wherein the array of photodiodes further comprises an additional three-photodiode-by-three-photodiode region that includes an additional set of four non-adjacent photodiodes, wherein the color filter array further comprises an additional set of four color filter elements formed over the additional set of four non-adjacent photodiodes, wherein each color filter element in the additional set of four color filter elements is configured to transmit light of the given wavelength band, and wherein each of the photodiodes in the additional set of four non-adjacent photodiodes is coupled to the shared floating diffusion node.

4 . The imaging system defined in claim 2 , wherein the three-photodiode-by-photodiode region is a first three-photodiode-by-three-photodiode region, wherein the array of photodiodes further comprises an additional three-photodiode-by-three-photodiode region that includes an additional set of four non-adjacent photodiodes, wherein at least two photodiodes in the additional set of four non-adjacent photodiodes are also included in the first three-photodiode-by-three-photodiode region, wherein the color filter array further comprises an additional set of four color filter elements formed over the additional set of four non-adjacent photodiodes, wherein each color filter element in the additional set of four color filter elements is configured to transmit light of an additional wavelength band that is different than the given wavelength band, and wherein each photodiode in the second set of four non-adjacent photodiodes is coupled to the shared floating diffusion node.

5 . The imaging system defined in claim 2 , wherein a first photodiode in the set of four non-adjacent photodiodes is configured to generate a first charge during a first integration time, and wherein a second photodiode in the set of four non-adjacent photodiodes is configured to generate a second charge during a second integration time that is different than the first integration time.

6 . The imaging system defined in claim 5 , wherein a third photodiode in the set of four non-adjacent photodiodes is configured to generate a third charge during a third integration time that is different than the first and second integration times.

7 . The imaging system defined in claim 6 , wherein a fourth photodiode in the set of four non-adjacent photodiodes is configured to generate a fourth charge during a fourth integration time that is different than the first, second, and third integration times.

8 . The imaging system defined in claim 5 , wherein the first photodiode and the second photodiode are diagonally opposed.

9 . The imaging system defined in claim 8 , wherein the array of photodiodes further comprises an additional three-photodiode-by-three-photodiode region that includes an additional set of four non-adjacent photodiodes, wherein the color filter array further comprises an additional set of four color filter elements formed over the additional set of four non-adjacent photodiodes, wherein each color filter element in the additional set of four color filter elements is configured to transmit light of the given wavelength band, wherein each of the photodiodes in the additional set of four non-adjacent photodiodes is coupled to an additional shared floating diffusion node, wherein a third photodiode in the additional set of four non-adjacent photodiodes is configured to generate a third charge during the first integration time, wherein a fourth photodiode in the additional set of four non-adjacent photodiodes is configured to generate a fourth charge during the second integration time, wherein the third and fourth photodiodes are diagonally opposed, wherein the first and fourth photodiodes are formed in a first row of the array of photodiodes, and wherein the second and third photodiodes are formed in a second row of the array of photodiodes.

10 . The imaging system defined in claim 1 wherein first and second photodiodes in the set of four non-adjacent photodiodes are coupled to the shared floating diffusion node through respective first and second charge transfer gates, wherein the first charge transfer gate is configured to transfer a first charge from the first photodiode to the shared floating diffusion node and the second charge transfer gate is configured to transfer a second charge from the second photodiode to the shared floating diffusion node, the imaging system further comprising:
readout circuitry coupled to the array, wherein the readout circuitry is operable in a low resolution mode in which the readout circuitry reads out image signals corresponding to a sum of the first and second charges from the shared charge floating diffusion node and in a high resolution mode in which the readout circuitry reads out image signals corresponding to a given one of the first and second charges from the shared floating diffusion node.

11 . The imaging system defined in claim 10 , further comprising:
a charge storage region coupled to the shared floating diffusion node through a dual conversion gain gate.

12 . The imaging system defined in claim 11 , further comprising:
control circuitry coupled to the array, wherein the control circuitry is configured to turn on the dual conversion gain gate when the readout circuitry is in the low resolution mode, and wherein the control circuitry is configured to turn off the dual conversion gain gate when the readout circuitry is in the high resolution mode.

13 . An imaging system, comprising:
an array of image pixels arranged in rows and columns comprising:
first, second, and third rows of image pixels, wherein the second row of image pixels is interposed between the first and third rows of image pixels;
first, second, and third columns of image pixels, wherein the second column of image pixels is interposed between the first and third columns of image pixels; and
a cluster of four non-adjacent image pixels, wherein a first image pixel in the cluster is formed in the first row and the first column, a second image pixel in the cluster is formed in the first row and the third column, a third image pixel in the cluster is formed in the third row and the first column, a fourth image pixel in the cluster is formed in the third row and the third column, and wherein each of the first, second, third, and fourth image pixels is coupled to a shared charge storage region; and
a color filter array formed over the array of image pixels that includes color filter elements configured to transmit a given color of light to each of the first, second, third, and fourth image pixels.

14 . The imaging system defined in claim 13 , wherein each of the first, second, third, and fourth image pi

Assignees

• Semiconductor Components Ind Llc

Inventors

• Mauritzson Richard A
• Mlinar Marko

Classifications

• H04N25/778

  comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself · CPC title

• H04N25/59

  by controlling the amount of charge storable in the pixel, e.g. modification of the charge conversion ratio of the floating node capacitance · CPC title

• H04N25/70

  SSIS architectures; Circuits associated therewith · CPC title

• H04N25/533

  by using differing integration times for different sensor regions · CPC title

• H04N25/134

  based on three different wavelength filter elements · CPC title