Image sensor and row averaging method for image sensor

• US 9,006,631 B2
• Filed: 02/08/2012
• Issued: 04/14/2015
• Est. Priority Date: 10/04/2011
• Status: Active Grant

• Current Assignee: DB HiTek Co., Ltd.
• Original Assignee: Dongbu HiTek Co., Ltd.
• Inventors: Oh, Hack Soo, Kwon, Jeongmi
• Primary Examiner(s): PYO, KEVIN K
• Application Number:
  US13/368,633
• Publication Number:
  US 20130082164A1
• Time in Patent Office: 1,161 Days
• Field of Search: 250/208.1, 250/214.P, 250/214.R, 250/214.SW, 348/272, 348/281, 348/302, 348/304, 348/308, 348/312, 348/E3.02
• US Class Current: 250/208.1
• CPC Class Codes: H01L 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/713 Transfer or readout registers; Split readout registers or multiple readout registers
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array

Abstract

An image sensor and a row averaging method for an image sensor capable of simultaneously selecting the pixels of the same color in the same column of different rows in a pixel array and performing a signal process, thereby preventing an increase in an area and a decrease in the sensing speed of the pixels in the sub-sampling mode and the binning mode of the image sensor.

Claims

1. An image sensor having a pixel array with a plurality of pixels in rows and columns, the image sensor comprising:

a plurality of light-receiving units in the pixels in the pixel array, each light-receiving unit configured to generate a pixel signal;

a signal processing unit configured to read and process the pixel signals from the light-receiving units and perform a signal process, the signal processing unit comprising a selection transistor that simultaneously selects pixels of different rows having a same color arrangement, a reset transistor that simultaneously initializes the pixels in a same column and different rows, and a transfer transistor that simultaneously transfers the pixel signals in the same column to a signal detection unit; and

a timing control unit configured to turn on selection transistors of different rows to select different rows of pixels of the same color in the same column without storing previous information, simultaneously turn on the reset transistors of the different rows in the same column then simultaneously turn off the reset transistors of the different rows in the same column to initialize the corresponding pixels in the same column, then simultaneously turn on the transfer transistors in the same column then simultaneously turn off the transfer transistors in the same column to transfer the pixel signals in the same column to the signal detection unit so as to obtain an average of the pixel signals subjected to the signal process.

2. The image sensor of claim 1, wherein an average value of the pixel signals of the pixels of the same color is output through the signal processing unit.

3. The image sensor of claim 1, wherein the timing control unit is configured to perform control such that selection transistors of different rows are simultaneously turned on to select different rows, reset transistors of the pixels in the same column are simultaneously turned on/off to simultaneously initialize the pixels in the same column of different rows, and transfer transistors of the pixels in the same column are simultaneously turned on/off to simultaneously transfer the signals of the pixels in the same column to a signal detection unit.

8. The image sensor of claim 1, wherein each signal processing unit further comprises a floating diffusion area connected to the reset transistor and the transfer transistor of the signal processing unit.

9. The image sensor of claim 8, wherein the floating diffusion area is a source-follower area.

10. The image sensor of claim 8, wherein reset noise and temporary noise in the floating diffusion areas generated during row selecting and/or pixel initializing are averaged.

4. A row averaging method for an image sensor having a pixel array with a plurality of pixels arranged in rows and columns, the method comprising:

generating a pixel signal with a light-receiving unit in each pixel;

simultaneously performing a signal process on pixel signals of pixels of a same color in a same column and different rows in the pixel array without storing previous information so as to obtain an average and outputting an average value of the pixel signals of the pixels, wherein the signal process comprises;

reading and processing the pixel signals from the light-receiving units,

simultaneously selecting pixels of different rows having the same color arrangement without storing previous information by turning on selection transistors of different rows of pixels of the same color in the same column,

simultaneously initialing the pixels in the same column and different rows by simultaneously turning on reset transistors of the different rows in the same column then simultaneously turning off the reset transistors of the different rows in the same column, then

simultaneously transferring the pixel signals in the same column to a signal detection unit by simultaneously turning on the transfer transistors in the same column then simultaneously turning off the transfer transistors in the same column

so as to obtain an average of the pixel signals subjected to the signal process.

5. The row averaging method of claim 4, wherein outputting the average value further comprises:

simultaneously outputting the pixel signals of the pixels in the same column and the different rows.

11. The row averaging method of claim 4, wherein the signal detection unit comprises one of the reset transistors and a corresponding one of the transfer transistors.

12. The row averaging method of claim 11, wherein simultaneously initializing the pixels in the same column and different rows and simultaneously transferring the pixel signals in the same column to the signal detection unit refreshes a floating diffusion area connected to the reset transistor and the transfer transistor of the signal processing unit.

13. The image sensor of claim 12, wherein the floating diffusion area is a source-follower area.

14. The image sensor of claim 12, wherein simultaneously selecting pixels of different rows having the same color arrangement and simultaneously initializing the pixels in the same column and different rows generates reset noise and temporary noise in the floating diffusion areas, and the method averages and outputs the generated reset noise and temporary noise.

6. A row averaging method for an image sensor having a pixel array with a plurality of pixels arranged in rows and columns, the method comprising:

generating the pixel signals with light-receiving units, each light-receiving unit comprising a pixel;

simultaneously selecting pixels of a same color in a same column and different rows in the pixel array without storing previous information so as to obtain an average;

performing a signal process on respective pixel signals of the selected pixels of the same color, wherein the signal process comprises;

reading and processing the pixel signals from the light-receiving units,

simultaneously selecting pixels of different rows having the same color arrangement without storing previous information by turning on selection transistors of different rows of pixels of the same color in the same column,

simultaneously initializing the pixels in the same column and different rows by simultaneously turning on reset transistors of the different rows in the same column then simultaneously turning off the reset transistors of the different rows in the same column, then

simultaneously transferring the pixel signals in the same column to a signal detection unit by simultaneously turning on the transfer transistors in the same column then simultaneously turning off the transfer transistors in the same column

so as to obtain an average of the pixel signals subjected to the signal process.

7. The row averaging method of claim 6, further comprising:

outputting an average value of the pixel signals.

15. The row averaging method of claim 6, wherein the signal detection unit comprises one of the reset transistors and a corresponding one of the transfer transistors.

16. The row averaging method of claim 15, wherein simultaneously initializing the pixels in the same column and different rows and simultaneously transferring the pixel signals in the same column to the signal detection unit refreshes a floating diffusion area connected to the reset transistor and the transfer transistor of the signal processing unit.

17. The image sensor of claim 16, wherein the floating diffusion area is a source-follower area.

18. The image sensor of claim 16, wherein simultaneously selecting pixels of different rows having the same color arrangement and simultaneously initializing the pixels in the same column and different rows generates reset noise and temporary noise in the floating diffusion areas, and the method averages and outputs the generated reset noise and temporary noise.