Solid-state imaging device, driving method thereof, camera, and driving method thereof
View Patent ↗A solid-state imaging device includes an imaging region having a plurality of pixels arranged. Each of the pixels includes a photoelectric converting portion and a charge converting portion for converting a charge generated by photoelectric conversion into a pixel signal. Further each pixel includes a first gate portion for charge accumulation and a second gate portion for charge readout that are formed between the photoelectric converting portion and a floating diffusion portion.
1. A solid-state imaging device comprising
an imaging region including a plurality of pixels arranged, wherein
each of the pixels includes a photoelectric converting portion and a charge converting portion for converting a charge generated by photoelectric conversion into a pixel signal, and
a first gate portion for charge accumulation and a second gate portion for charge readout are formed between the photoelectric converting portion and a floating diffusion portion.
2. A solid-state imaging device according to claim 1 , wherein
a gate voltage of the first gate portion and a gate voltage of the second gate portion are defined independently from each other.
3. A solid-state imaging device according to claim 1 , wherein
the first gate portion is actuated in the middle of a charge accumulation period of the pixel to increase a saturated amount of charge accumulated in the photoelectric converting portion, and
the second gate portion is actuated after completing the charge accumulation period to read out the charge of the photoelectric converting portion to the floating diffusion portion.
4. A solid-state imaging device according to claim 1 , wherein
a threshold below the first gate portion on a side of the photoelectric converting portion is set up higher than a threshold below the second gate portion on a side of the floating diffusion portion.
5. A solid-state imaging device according to claim 4 , wherein
a gate electrode of the first gate portion is formed to partially cover a gate electrode of the second gate portion.
6. A solid-state imaging device according to claim 4 , wherein
an impurity concentration below the first gate portion is different from an impurity concentration below the second gate portion.
7. A solid-state imaging device according to claim 4 , wherein
a gate length of the first gate portion is different from a gate length of the second gate portion.
8. A method of driving a solid-state imaging device including a plurality of pixels each having a photoelectric converting portion and a floating diffusion portion, comprising the steps of:
forming a first gate portion for charge accumulation and a second gate portion for charge readout between the photoelectric converting portion and the floating diffusion portion; and
actuating the first gate portion in the middle of a charge accumulation period of the pixel to increase an overflow level of the photoelectric converting portion and extend a dynamic range.
9. A method of driving a solid-state imaging device according to claim 8 , further comprising the steps of:
initiating charge accumulation up to the overflow level of the photoelectric converting portion;
actuating the first gate portion in the middle of the charge accumulation period to increase the overflow level of the photoelectric converting portion and continuing the charge accumulation, and
actuating the second gate portion after completing the charge accumulation period to read out a charge from the photoelectric converting portion to the floating diffusion portion.
10. A method of driving a solid-state imaging device according to claim 8 , wherein
the first gate portion is actuated after releasing an electronic shutter but before reading out the accumulated charge at a timing, which is out of a CDS period of a pixel on another line.
11. A camera comprising
a solid-state imaging device that includes an imaging region having a plurality of pixels arranged, wherein
each of the pixels includes a photoelectric converting portion and a charge converting portion for converting a charge generated by photoelectric conversion into a pixel signal, and
a first gate portion for charge accumulation and a second gate portion for charge readout are formed between the photoelectric converting portion and a floating diffusion portion.
12. A method of driving a camera including a solid-state imaging device having a plurality of pixels each including a photoelectric converting portion and a floating diffusion portion, comprising the steps of:
forming a first gate portion for charge accumulation and a second gate portion for charge readout between the photoelectric converting portion and the floating diffusion portion; and
actuating the first gate portion in the middle of a charge accumulation period of the pixel to increase an overflow level of the photoelectric converting portion and extend a dynamic range.