Solid-state imaging device and method of operating the same, and electronic apparatus and method of operating the same

1. An imaging device, comprising:

a plurality of pixels, each including:

a photoelectric conversion element;

a transfer gate;

a floating diffusion; and

a charge holding element disposed between the transfer gate and the floating diffusion,

wherein, for each of the plurality of pixels, the charge holding element includes a plurality of electrodes.

2. The imaging device of claim 1 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause the charge holding element of a given pixel of the plurality of pixels to transfer the electric charge held therein to the corresponding floating diffusion by sequentially supplying an OFF potential to the plurality of electrodes of the given pixel.

3. The imaging device of claim 1 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to drive the plurality of pixels to perform a global shutter imaging operation.

4. The imaging device of claim 1 ,

wherein the plurality of pixels are grouped into units each comprising j pixels, j being an integer greater than 1, where each of the pixels that is included in a same unit corresponds to a same floating diffusion.

5. The imaging device of claim 4 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given unit to perform an additive readout operation that includes transferring the electric charges held in the respective charge holding elements of each of the pixels of the given unit to the corresponding floating diffusion such that the corresponding floating diffusion adds together the electric charges transferred from the pixels of the given unit.

6. The imaging device of claim 4 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given unit to perform a partial additive readout operation including:

for each of the pixels of the given unit, turning on less than all of the plurality of electrodes of the charge holding element of the respective pixel while the charge holding element of the respective pixel receives the electric charge from the photoelectric conversion element of the respective pixel, and

transferring the electric charges held in the respective charge holding elements of each of the pixels of the given unit to the corresponding floating diffusion such that the corresponding floating diffusion adds together the electric charges transferred from the pixels of the given unit.

7. The imaging device of claim 4 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured selectively read out a given unit according to one of a plurality of readout modes that the control circuit is configured to selectively switch between, the plurality of readout modes including:

an individual pixel readout mode in which the electric charge of the charge holding element of each pixel of the given unit is read out individually,

an additive readout mode in which the electric charge of the charge holding element of each pixel of the given unit is added together by the corresponding floating diffusion and read out collectively, and

a partial additive readout mode in which, for each of the pixels of the given unit, less than all of the plurality of electrodes of the charge holding element of the respective pixel are turned on while the charge holding element of the respective pixel receives the electric charge from the photoelectric conversion element of the respective pixel and the electric charge of the charge holding element of each pixel of the given unit is added together by the corresponding floating diffusion and read out collectively.

8. The imaging device of claim 1 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given pixel of the plurality of pixels to perform a partial readout operation that includes turning on less than all of the plurality of electrodes of the charge holding element of the given pixel while the charge holding element of the given pixel receives the electric charge from the photoelectric conversion element of the given pixel.

9. The imaging device of claim 1 ,

wherein each of the plurality of pixel includes a first transfer gate that selectively electrically separates the photoelectric conversion element of the respective pixel from the charge holding element of the respective pixel, and a second transfer gate that selectively electrically separates the charge holding element of the respective pixel from the corresponding floating diffusion.

10. The imaging device of claim 9 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes, and

the plurality of sub-regions are arranged in series between the first and second transfer gates.

11. The imaging device of claim 9 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes, and

the plurality of sub-regions are arranged such that each adjoins the photoelectric conversion element of the respective pixel with no other one of the plurality of sub-regions intervening therebetween.

12. The imaging device of claim 11 ,

wherein, for each of the plurality of pixels, the plurality of sub-regions are arranged such that a first direction is transverse to a second direction,

the first direction is a direction in which charge is transferred into the charge holding element through the first transfer gate, and

the second direction is a direction in which charge is transferred out from the charge holding element through the second transfer gate.

13. The imaging device of claim 1 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes,

the plurality of sub-regions are arranged such that a first direction is transverse to a second direction,

the first direction is a direction in which charge is transferred into the charge holding element, and

the second direction is a direction in which charge is transferred out from the charge holding element.

14. The imaging device of claim 1 ,

wherein the charge holding element of each of the plurality of pixels is configured such that at least one of the plurality of electrodes thereof also controls transfer of the electric charge from the photoelectric conversion element of the respective pixel to the charge holding element of the respective pixel.

15. The imaging device of claim 1 ,

wherein, for a given pixel of the plurality of pixels, at least one of the plurality of electrodes of the charge holding element thereof is a different size from at least one other of the plurality of electrodes of the charge holding element thereof.

16. The imaging device of claim 1 ,

wherein each of the plurality of pixels further includes a photoelectric-conversion-element-reset gate that abuts the photoelectric conversion element and selectively connects the photoelectric conversion element to a reset drain.

17. The imaging device of claim 1 ,

wherein each of the plurality of pixels further includes a light shielding unit configured to shield the charge holding element from the incident light, and an electrode of at least one of the holding units is directly electrically connected to the light shielding unit.

18. The imaging device of claim 1 ,

wherein the plurality of electrodes include a first electrode and a second electrode,

wherein the floating diffusion is nearer to the second electrode than to the first electrode, and

wherein the second electrode is larger than the first electrode.

19. The imaging device of claim 1 ,

wherein each of the plurality of pixels further includes a floating gate disposed between the floating diffusion and the plurality of electrodes.

20. The imaging device of claim 1 ,

wherein each of the plurality of pixels further includes a global reset gate disposed between a reset drain and the photoelectric conversion element.

21. An imaging device, comprising:

a plurality of pixels, each including:

a photoelectric conversion element that converts incident light into electric charge;

a charge holding element including a plurality of electrodes; and

a floating diffusion that receives the electric charge from the photoelectric conversion element via the charge holding element.

22. The imaging device of claim 21 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause the charge holding element of a given pixel of the plurality of pixels to transfer the electric charge held therein to the corresponding floating diffusion by sequentially supplying an OFF potential to the plurality of electrodes of the given pixel.

23. The imaging device of claim 21 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to drive the plurality of pixels to perform a global shutter imaging operation.

24. The imaging device of claim 21 ,

wherein the plurality of pixels are grouped into units each comprising j pixels, j being an integer greater than 1, where each of the pixels that is included in a same unit corresponds to a same floating diffusion.

25. The imaging device of claim 24 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given unit to perform an additive readout operation that includes transferring the electric charges held in the respective charge holding elements of each of the pixels of the given unit to the corresponding floating diffusion such that the corresponding floating diffusion adds together the electric charges transferred from the pixels of the given unit.

26. The imaging device of claim 24 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given unit to perform a partial additive readout operation including:

for each of the pixels of the given unit, turning on less than all of the plurality of electrodes of the charge holding element of the respective pixel while the charge holding element of the respective pixel receives the electric charge from the photoelectric conversion element of the respective pixel, and

transferring the electric charges held in the respective charge holding elements of each of the pixels of the given unit to the corresponding floating diffusion such that the corresponding floating diffusion adds together the electric charges transferred from the pixels of the given unit.

27. The imaging device of claim 24 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured selectively read out a given unit according to one of a plurality of readout modes that the control circuit is configured to selectively switch between, the plurality of readout modes including:

an individual pixel readout mode in which the electric charge of the charge holding element of each pixel of the given unit is read out individually,

an additive readout mode in which the electric charge of the charge holding element of each pixel of the given unit is added together by the corresponding floating diffusion and read out collectively, and

a partial additive readout mode in which, for each of the pixels of the given unit, less than all of the plurality of electrodes of the charge holding element of the respective pixel are turned on while the charge holding element of the respective pixel receives the electric charge from the photoelectric conversion element of the respective pixel and the electric charge of the charge holding element of each pixel of the given unit is added together by the corresponding floating diffusion and read out collectively.

28. The imaging device of claim 21 , further comprising:

a control circuit that controls operations of the plurality of pixels,

wherein the control circuit is configured to cause a given pixel of the plurality of pixels to perform a partial readout operation that includes turning on less than all of the plurality of electrodes of the charge holding element of the given pixel while the charge holding element of the given pixel receives the electric charge from the photoelectric conversion element of the given pixel.

29. The imaging device of claim 21 ,

wherein each of the plurality of pixel includes a first transfer gate that selectively electrically separates the photoelectric conversion element of the respective pixel from the charge holding element of the respective pixel, and a second transfer gate that selectively electrically separates the charge holding element of the respective pixel from the corresponding floating diffusion.

30. The imaging device of claim 29 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes, and

the plurality of sub-regions are arranged in series between the first and second transfer gates.

31. The imaging device of claim 29 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes, and

the plurality of sub-regions are arranged such that each adjoins the photoelectric conversion element of the respective pixel with no other one of the plurality of sub-regions intervening therebetween.

32. The imaging device of claim 31 ,

wherein, for each of the plurality of pixels, the plurality of sub-regions are arranged such that a first direction is transverse to a second direction,

the first direction is a direction in which charge is transferred into the charge holding element through the first transfer gate, and

the second direction is a direction in which charge is transferred out from the charge holding element through the second transfer gate.

33. The imaging device of claim 21 ,

wherein, for each of the plurality of pixels:

the charge holding element includes a plurality of sub-regions each corresponding to one of the plurality of electrodes,

the plurality of sub-regions are arranged such that a first direction is transverse to a second direction,

the first direction is a direction in which charge is transferred into the charge holding element, and

the second direction is a direction in which charge is transferred out from the charge holding element.

34. The imaging device of claim 21 ,

wherein the charge holding element of each of the plurality of pixels is configured such that at least one of the plurality of electrodes thereof also controls transfer of the electric charge from the photoelectric conversion element of the respective pixel to the charge holding element of the respective pixel.

35. The imaging device of claim 21 ,

wherein, for a given pixel of the plurality of pixels, at least one of the plurality of electrodes of the charge holding element thereof is a different size from at least one other of the plurality of electrodes of the charge holding element thereof.

36. The imaging device of claim 21 ,

wherein each of the plurality of pixels further includes a photoelectric-conversion-element-reset gate that abuts the photoelectric conversion element and selectively connects the photoelectric conversion element to a reset drain.

37. The imaging device of claim 21 ,

wherein each of the plurality of pixels further includes a light shielding unit configured to shield the charge holding element from the incident light, and an electrode of at least one of the holding units is directly electrically connected to the light shielding unit.

38. The imaging device of claim 21 ,

wherein the plurality of electrodes include a first electrode and a second electrode,

wherein the floating diffusion is nearer to the second electrode than to the first electrode, and

wherein the second electrode is larger than the first electrode.

39. The imaging device of claim 21 ,

wherein each of the plurality of pixels further includes a floating gate disposed between the floating diffusion and the plurality of electrodes.

40. The imaging device of claim 21 ,

wherein each of the plurality of pixels further includes a global reset gate disposed between a reset drain and the photoelectric conversion element.