Image sensor including at least one autofocusing pixel and at least one normal pixel and driving method thereof

1. A method of driving an image sensor, the image sensor including a plurality of pixels, the plurality of pixels including at least one autofocusing pixel and at least one normal pixel, each of the plurality of pixels including a plurality of photoelectric conversion elements, the method comprising:

reading out autofocusing pixel signals, which are photoelectrically converted by the plurality of photoelectric conversion elements included in one of the at least one autofocusing pixel, respectively, at different timings,

wherein the reading out the autofocusing pixel signals includes

applying a first transmission signal activated at a first timing to the at least one autofocusing pixel, and

applying a second transmission signal activated at a second timing different from the first timing to the at least one autofocusing pixel; and

reading out normal pixel signals, which are photoelectrically converted by the plurality of photoelectric conversion elements included one of the at least one normal pixels, respectively, simultaneously.

2. The method of claim 1 , wherein the reading out the autofocusing pixel signals includes applying the first transmission signal activated at the second timing to the at least one autofocusing pixel.

3. The method of claim 1 , wherein

the reading out the normal pixel signals includes applying a third transmission signal activated at a third timing after the second timing to the at least one normal pixel.

4. The method of claim 1 , wherein the reading out the autofocusing pixel signals includes:

obtaining a first sub pixel signal and a second sub pixel signal; and

detecting a phase difference between light incident to a first sub area and a second sub area of the at least one autofocusing pixel, based on the first sub pixel signal and the second sub pixel signal, wherein

the first sub area includes a first photoelectric conversion element among the plurality of photoelectric conversion elements of the at least one autofocusing pixel, and

the second sub area includes a second photoelectric conversion element among the plurality of photoelectric conversion elements of the at least one autofocusing pixel.

5. The method of claim 4 , wherein the obtaining the first sub pixel signal and the second sub pixel signal includes:

reading out the first sub pixel signal between the first timing and the second timing; and

reading out the second sub pixel signal after the second timing.

6. The method of claim 5 , wherein

the second transmission signal is deactivated at the first timing, and

the first transmission signal is deactivated at the second timing.

7. The method of claim 4 , wherein the obtaining the first sub pixel signal and the second sub pixel signal includes:

reading out the first sub pixel signal between the first timing and the second timing;

reading out a sum of the first sub pixel signal and the second sub pixel signal after the second timing; and

calculating a subtraction between the sum and the first sub pixel signal to obtain the second sub pixel signal.

8. The method of claim 7 , wherein

the second transmission signal is deactivated at the first timing, and

the first transmission signal is activated at the second timing.

9. The method of claim 4 , wherein:

the first sub pixel signal corresponds to photocharges generated by the first photoelectric conversion element, and

the second sub pixel signal corresponds to photocharges generated by the second photoelectric conversion element.

10. The method of claim 4 , further comprising:

determining autofocusing information corresponding to an external object based on the phase difference.

11. A method of driving an image sensor, the image sensor including a plurality of pixels, the plurality of pixels including at least one autofocusing pixel and at least one normal pixel, each of the plurality of pixels including a plurality of photoelectric conversion elements, the method comprising:

applying a first transmission signal activated at a first timing to the at least one autofocusing pixel to obtain a first sub pixel signal;

applying a second transmission signal activated at a second timing different from the first timing to the at least one autofocusing pixel to obtain a second sub pixel signal;

applying a third transmission signal activated at a third timing different from the second timing to the at least one normal pixel to obtain a pixel signal;

obtaining image data corresponding to at least one autofocusing pixel by using a sum of the first sub pixel signal and the second sub pixel signal; and

obtaining image data corresponding to at least one normal pixel by using the pixel signal.

12. The method of claim 11 , wherein the second timing is later than the first timing and earlier than the third timing.

13. The method of claim 11 , wherein

the at least one autofocusing pixel includes a first sub area and a second sub area,

the first sub pixel signal corresponds to photocharges of the first sub area, and

the second sub pixel signal corresponds to photocharges of the second sub area.

14. The method of claim 13 , further comprising:

detecting a phase difference between light incident to the first sub area and a second sub area of the at least one autofocusing pixel, based on the first sub pixel signal and the second sub pixel signal; and

determining autofocusing information corresponding to an external object based on the phase difference.

15. The method of claim 13 , wherein:

the at least one autofocusing pixel includes a floating diffusion node; and

in one of the at least one autofocusing pixel, the photocharges of the first sub area are transmitted to the floating diffusion node in response to activation of the first transmission signal and the photocharges of the second sub area are transmitted to the floating diffusion node in response to activation of the second transmission signal.

16. The method of claim 15 , wherein:

the floating diffusion node stores the photocharges of the first sub area, between the first timing and the second timing; and

the floating diffusion node stores the photocharges of the first sub area and the photocharges of the second sub area, after the second timing.

17. The method of claim 11 , wherein

the applying the first transmission signal includes applying the first transmission signal to a first transmission transistor of the at least one autofocusing pixel;

the applying the second transmission signal includes applying the second transmission signal to a second transmission transistor of the at least one autofocusing pixel, the second transmission transistor being different from the first transmission transistor; and

the applying the third transmission signal includes applying the third transmission signal to transmission transistors of the at least one normal pixel, simultaneously.

18. The method of claim 11 , wherein:

the third timing is the same as the first timing.

19. The method of claim 18 , wherein:

the third transmission signal is the same as the first transmission signal.