Image sensor including auto-focusing pixel and image processing system including the same

1. An image sensor comprising:

a pixel array including first to fourth pixels having an R, G, and B Bayer pattern;

an analog-to-digital converter (ADC) block configured to convert a pixel signal of each of the first to fourth pixels into a digital pixel signal; and

a control block configured to control the pixel array and the ADC block, wherein:

the first and fourth pixels are green pixels each including a green filter, the second pixel is a red pixel including a red filter, and the third pixel is a blue pixel including a blue filter,

each of the first and fourth pixels comprises two photo diodes separated in a first direction, and

at least one of the second and third pixels comprises two photo diodes separated in a second direction, which is different from the first direction.

2. The image sensor of claim 1 , wherein a difference between the first direction and the second direction is an angle of 90 degrees.

3. The image sensor of claim 1 , wherein

each of the second and third pixels comprises the two photo diodes separated in the second direction.

4. The image sensor of claim 1 , wherein

the other of the second and third pixels comprises the two photo diodes separated in the first direction.

5. The image sensor of claim 1 , wherein:

the first pixel comprise the two photo diodes separated in the first direction and the two photo diodes accumulate a photocharge corresponding to intensity of incident light passing through one micro-lens, and

the first pixel comprises a plurality of transistors configured to convert the photocharge accumulated in the two photo diodes thereof into first and second sub-pixel signals which are electrical signals and output the first and second sub-pixel signals, wherein a number of the plurality of transistors of each pixel is two or more.

6. The image sensor of claim 5 , wherein auto-focusing information is calculated based on a difference between the first and second sub-pixel signals.

7. The image sensor of claim 5 , wherein the first and second sub-pixel signals are simultaneously output via different sub-column lines.

8. The image sensor of claim 5 , wherein the first and second sub-pixel signals are sequentially output via the same column line.

9. An image sensor comprising:

a pixel array including a plurality of pixels having an R, G, and B Bayer pattern; and

an analog-to-digital converter (ADC) block configured to convert a pixel signal of each of the plurality of pixels into a digital pixel signal, wherein:

the plurality of pixels comprises:

a first-type pixel including two photo diodes separated in a first direction;

a second-type pixel including two photo diodes separated in a second direction which is different from the first direction; and

a third-type pixel including two photo diodes separated in the first direction,

each of the first-type pixel and third-type pixel is a green pixel including a green filter and the second-type pixel is a red pixel including a red filter or a blue pixel including a blue filter,

first auto-focusing information for the first direction is calculated based on a signal output from the first-type pixel, and

second auto-focusing information for the second direction is calculated based on a signal output from the second-type pixel.

10. The image sensor of claim 9 , wherein a difference between the first direction and the second direction is an angle of 90 degrees.

11. The image sensor of claim 9 , wherein each of the plurality of pixels further comprises:

one micro-lens; and

a plurality of transistors configured to convert photocharges accumulated in the two photo diodes into first and second sub-pixel signals, which are electrical signals, according to an intensity of light passing through the micro-lens, and output the first and second sub-pixel signals, wherein a number of the plurality of transistors of each pixel is two or more.

12. The image sensor of claim 11 , wherein:

the first auto-focusing information for the first direction is calculated based on a difference between the first and second sub-pixel signals of the first-type pixel, and

the second auto-focusing information for the second direction is calculated based on a difference between the first and second sub-pixel signals of the second-type pixel.

13. An image processing system comprising:

an image sensor comprising:

a pixel array including a plurality of auto-focusing pixels;

an analog-to-digital converter (ADC) block configured to convert a pixel signal of each of the plurality of auto-focusing pixels into a digital pixel signal; and

an image processor configured to extract auto-focusing information for an auto-focusing operation from the digital pixel signal, wherein:

the auto-focusing pixels comprise:

a first-type pixel including two photo diodes separated in a first direction;

a second-type pixel including two photo diodes separated in a second direction which is different from the first direction; and

a third-type pixel including two photo diodes separated in the first direction, and

each of the first-type pixel and third-type pixel is a green pixel including a green filter and the second-type pixel is a red pixel including a red filter or a blue pixel including a blue filter.

14. The image processing system of claim 13 , wherein a difference between the first direction and the second direction is an angle of 90 degrees.

15. The image processing system of claim 13 , wherein the auto-focusing information comprises:

auto-focusing information for the first direction; and

auto-focusing information for the second direction, wherein

the image processor calculates the auto-focusing information for the first direction, based on a digital pixel signal output from the first-type pixel, and calculates the auto-focusing information for the second direction, based on a digital pixel signal output from the second-type pixel.