Image sensor and image capture device using the same

Patent metadata

Field	Value
Publication number	US-2017195593-A1
Application number	US-201615152322-A
Country	US
Kind code	A1
Filing date	May 11, 2016
Priority date	Jan 6, 2016
Publication date	Jul 6, 2017
Grant date	—

Abstract

The present disclosure illustrates an image sensor. The image sensor includes an image sensing array and a voltage supply array. The image sensing array and the voltage supply array are coupled to an analog-to-digital converter array. The image sensing array captures image data. The image sensing array supports one of a rolling shutter mechanism and a global shutter mechanism according to setting. The voltage supply array includes a plurality of voltage supply circuits to supply dummy voltage. During an auto-zero period, the voltage supply array provides the dummy voltage to the analog-to-digital converter array. Pluralities of comparators of the analog-to-digital converter array execute an auto-zero function based on the dummy voltage. After finishing the auto-zero function, the image sensing array outputs the image data to the analog-to-digital converter array. The analog-to-digital converter array makes the image data be digital.

First claim

What is claimed is:

1 . An image sensor, connected to an analog-to-digital converter array, wherein the analog-to-digital converter array comprises a plurality of comparators, the image sensor comprising:
an image sensing array, capturing image data, comprising a plurality of pixels, wherein the image sensing array is set to support one of a rolling shutter mechanism and a global shutter mechanism; and a voltage supply array, connected to the analog-to-digital converter array, comprising a plurality of voltage supply circuits to provide a dummy voltage; wherein during an auto-zero period, the voltage supply array provides the dummy voltage to the analog-to-digital converter array, the comparators execute an auto-zero function according to the dummy voltage, the image sensing array outputs the image data to the analog-to-digital converter array after the comparators complete the auto-zero function, and the analog-to-digital converter array makes the image data be digital.

2 . The image sensor according to claim 1 , wherein the analog-to-digital converter array further comprises:
a plurality of counters, respectively connected to output ends of the comparators, the counting values of the counters increasing with time; wherein the output ends of the counters are connected to an image processing circuit, and the image processing circuit determines gray level values of the digital image data according to the counting values output by the counters.

3 . The image sensor according to claim 2 , wherein the comparators respectively enter into a comparison mode after completing the auto-zero function, during a first comparison period, the image sensing array provides part of the image data row by row to the analog-to-digital converter array, the comparators respectively compare the image data with a ramp voltage and output a first comparison result to the corresponding counters, the counters adjust the counting values according to the first comparison results, and the counters stop counting and output the current counting values to the image processing circuit if the first comparison result indicates that the ramp voltage is less than the voltage of the image data.

4 . The image sensor according to claim 3 , wherein during a second comparison period, the image sensing array resets a floating diffusion region of each pixel and provides a reference voltage row by row to the analog-to-digital converter array, the comparators respectively compare the reference voltage with the ramp voltage and output a second comparison result to the corresponding counters, and the counters stop counting and output the current counting values to the image processing circuit if the second comparison result indicates that the ramp voltage is less than the reference.

5 . The image sensor according to claim 4 , wherein the image processing circuit respectively calculates the gray level value of the image data and the gray level value of the reference voltage according to the counting values provided by the counters during the first comparison period and the second comparison period, and the image processing circuit calculates the difference between the gray level value of the image data and the gray level value of the reference voltage to obtain the gray level value of a real image.

6 . The image sensor according to claim 1 , wherein the amount of the comparators corresponds to the column number of the image sensing array, and the pixels in the same column in the image sensing array are connected to the same comparator.

7 . The image sensor according to claim 1 , wherein the image sensing array is a CMOS image sensing array.

8 . The image sensor according to claim 1 , wherein the pixels respectively have a three-transistor configuration, a four-transistor configuration or a five-transistor configuration.

9 . The image sensor according to claim 1 , wherein the voltage supply circuit comprises:
a plurality of shading pixels, respectively connected to the comparators to provide the dummy voltage to the comparators; wherein the light-sensing elements of the shading pixels are shaded such that the voltages of floating diffusion regions of the shading pixels are stable, and the shading pixels provide the stable dummy voltage according to the voltages of the floating diffusion regions.

10 . The image sensor according to claim 9 , wherein the shading pixels respectively have a three-transistor configuration, a four-transistor configuration or a five-transistor configuration.

11 . An image capture device, comprising:
an image capture sensor, comprising a plurality of comparators; and an image sensor, connected to the analog-to-digital converter array, comprising:
an image sensing array, capturing image data, comprising a plurality of pixels, wherein the image sensing array is set to support one of a rolling shutter mechanism and a global shutter mechanism; and
a voltage supply array, connected to the analog-to-digital converter array, comprising a plurality of voltage supply circuits to provide a dummy voltage;
wherein during an auto-zero period, the voltage supply array provides the dummy voltage to the analog-to-digital converter array, the comparators execute an auto-zero function according to the dummy voltage, the image sensing array outputs the image data to the analog-to-digital converter array after the comparators complete the auto-zero function, and the analog-to-digital converter array converts the image data to digital image data.

12 . The image capture device according to claim 11 , wherein the analog-to-digital converter array further comprises:
a plurality of counters, respectively connected to output ends of the comparators, the counting values of the counters increasing with time; wherein the output ends of the counters are connected to an image processing circuit, and the image processing circuit determines gray level values of the digital image data according to the counting values output by the counters.

13 . The image capture device according to claim 12 , wherein the comparators respectively enter into a comparison mode after completing the auto-zero function, during a first comparison period, the image sensing array provides part of the image data row by row to the analog-to-digital converter array, the comparators respectively compare the image data with a ramp voltage and output a first comparison result to the corresponding counters, the counters adjust the counting values according to the first comparison results, and the counters stop counting and output the current counting values to the image processing circuit if the first comparison result indicates that the ramp voltage is less than the voltage of the image data.

14 . The image capture device according to claim 13 , wherein during a second comparison period, the image sensing array resets a floating diffusion region of each pixel and provides a reference voltage row by row to the analog-to-digital converter array, the comparators respectively compare the reference voltage with the ramp voltage and output a second comparison result to the corresponding counters, and the counters stop counting and output the current counting values to the image processing circuit if the second comparison result indicates that the ramp voltage is less than the reference.

15 . The image capture device according to claim 14 , wherein the image processing circuit respectively calculates the gray level value of the image data and the gray level value of the reference voltage according to the counting values provided by the counters during the first comparison period and

Assignees

• Pixart Imaging Inc

Inventors

• Yeh Mei-Chao

Classifications

• H04N25/77

  Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components · CPC title

• H04N23/73

  by influencing the exposure time · CPC title

• H04N25/531 Primary

  by controlling rolling shutters in CMOS SSIS · CPC title

• H04N5/3745

  Electricity · mapped topic

• H04N5/3532 Primary

  Electricity · mapped topic