Imaging device and camera system including sense circuits to make binary decision
An imaging device includes: a pixel array section having an array of pixels, each of which has a photoelectric converting device and outputs an electric signal according to an input photon; a sense circuit section having a plurality of sensor circuits each of which makes binary decision on whether there is a photon input to a pixel in a predetermined period upon reception of the electric signal therefrom; and a decision result IC section which integrates decision results from the sense circuits, pixel by pixel or for each group of pixels, multiple times to generate imaged data with a gradation, the decision result IC section including a count circuit which performs a count process to integrate the decision results from the sense circuits, and a memory for storing a counting result for each pixel from the count circuit, the sense circuits sharing the count circuit for integrating the decision results.
1. An imaging device comprising:
a photoelectric converting device that outputs one or more signals according to one or more input photons;
a reset transistor configured to reset the photoelectric converting device according to a first exposure period and a second exposure period;
a sense circuit that performs one or more binary decisions based on the one or more signals from the photoelectric converting device during the first exposure period and the second exposure period and outputs one or more decision results based on the one or more binary decisions, and
decision result circuitry including a count circuit configured to perform a count process to integrate decision results from the sense circuit, and a memory configured to store a counting result from the count circuit, wherein the decision result circuitry is configured to store a counting result of the second exposure period in the memory upon determination that a counting result of the first exposure period exceeds a predetermined value.
2. The imaging device according to claim 1 , wherein
the photoelectric converting device and the reset transistor are arranged on a first substrate,
the sense circuit, the decision result circuitry, and the memory are arranged on a second substrate,
the first substrate and the second substrate are laminated on one another, and
the photoelectric converting device faces the sense circuit.
3. The imaging device according to claim 2 , wherein
the first substrate includes an array of a plurality of pixels, each pixel in the plurality of pixels having a photoelectric converting device that outputs a signal according to an input photon, and
the second substrate includes a plurality of sense circuits, the plurality of sense circuits performing binary decisions based on signals from the photoelectric converting devices in a predetermined period and outputting decision results based on the binary decisions.
4. The imaging device according to claim 3 , wherein
the plurality of sense circuits are arranged in an array, and
the plurality of pixels and the plurality of sense circuits are formed in a one-to-one correspondence.
5. The imaging device according to claim 4 , wherein
each pixel in the plurality of pixels is connected to a respective sense circuit in the plurality of sense circuits via a signal line.
6. The imaging device according to claim 4 , wherein
the decision result circuitry includes a plurality of count circuits, and
every predetermined number of sense circuits share a respective count circuit.
7. The imaging device according to claim 6 , wherein
the plurality of sense circuits are laid out in a matrix form in a row direction and in a column direction, and
sense circuits which are located in a same row or a same column share a respective count circuit.
8. The imaging device according to claim 1 , wherein
the first exposure period is longer than the second exposure period.
9. The imaging device according to claim 8 , wherein
bits of the counting result of the second exposure period stored in the memory are shifted a number of bits corresponding to a ratio of a length of the first exposure period to the second exposure period.
10. A method comprising:
outputting, by a photoelectric converting device, one or more signals according to one or more input photons;
resetting, by a reset transistor, the photoelectric converting device according to a first exposure period and a second exposure period;
performing, by a sense circuit, one or more binary decisions based on the one or more signals from the photoelectric converting device during the first exposure period and the second exposure period;
outputting, by the sense circuit, one or more decision results based on the one or more binary decisions;
performing, by a decision result circuitry including a count circuit, a count process to integrate decision results from the sense circuit; and
storing, by a memory, a counting result of the second exposure period upon determination that a counting result of the first exposure period exceeds a predetermined value.
11. The method according to claim 10 , wherein
the photoelectric converting device and the reset transistor are arranged on a first substrate,
the sense circuit, the decision result circuitry, and the memory are arranged on a second substrate,
the first substrate and the second substrate are laminated on one another, and
the photoelectric converting device faces the sense circuit.
12. The method according to claim 11 , wherein
the first substrate includes an array of a plurality of pixels, each pixel in the plurality of pixels having a photoelectric converting device that outputs a signal according to an input photon, and
the second substrate includes a plurality of sense circuits, the plurality of sense circuits performing binary decisions based on signals from the photoelectric converting devices in a predetermined period and outputting decision results based on the binary decisions.
13. The method according to claim 12 , wherein
the plurality of sense circuits are arranged in an array, and
the plurality of pixels and the plurality of sense circuits are formed in a one-to-one correspondence.
14. The method according to claim 13 , wherein
each pixel in the plurality of pixels is connected to a respective sense circuit in the plurality of sense circuits via a signal line.
15. The method according to claim 13 , wherein
the decision result circuitry includes a plurality of count circuits, and
every predetermined number of sense circuits share a respective count circuit.
16. The method according to claim 15 , wherein
the plurality of sense circuits are laid out in a matrix form in a row direction and in a column direction, and
sense circuits which are located in a same row or a same column share a respective count circuit.
17. The method according to claim 10 , wherein
the first exposure period is longer than the second exposure period.
18. The method according to claim 17 , further comprising:
shifting bits of the counting result of the second exposure period stored in the memory a number of bits corresponding to a ratio of a length of the first exposure period to the second exposure period.