Photoelectric conversion apparatus, photoelectric conversion system, and driving method for the photoelectric conversion apparatus

• US 9,781,374 B2
• Filed: 07/30/2015
• Issued: 10/03/2017
• Est. Priority Date: 07/31/2014
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hashimoto, Seiji, Takahashi, Hidekazu, Furubayashi, Atsushi
• Primary Examiner(s): Flohre, Jason
• Application Number:
  US14/814,058
• Publication Number:
  US 20160037113A1
• Time in Patent Office: 796 Days
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/771 comprising storage means other than floating diffusion

Abstract

An output control unit configured to set an amplitude of a signal output to a signal line to be smaller as compared with a case where an amplification unit outputs a signal on the basis of a potential of the input node or put the amplification unit into a non-operating state is provided.

Claims

1. A photoelectric conversion apparatus comprising:

a photoelectric conversion unit;

a signal line;

a reset unit having an input node, and an output node connected to a floating diffusion node;

a driving unit connected to the floating diffusion node;

an amplification unit having an input node, and an output node connected to the signal line; and

an output control unit, wherein the photoelectric conversion unit includes a first electrode, a second electrode, a photoelectric conversion layer that is arranged between the first electrode and the second electrode and accumulates signal carriers, and an insulating layer arranged between the photoelectric conversion layer and the second electrode,

a magnitude relationship between a potential applied to the first electrode and a first potential applied to the second electrode by the driving unit is a first relationship in a first period,

in the first period, the input node is supplied with a potential corresponding to the first potential, and the amplification unit outputs a signal corresponding to the potential of the input node, to the signal line,

in a second period, the magnitude relationship is in a second relationship that is opposite of the first relationship by changing a potential applied to the second electrode by the driving unit from the first potential to a second potential,

in a third period, during which the amplification unit outputs a signal corresponding to a potential of the input node, the potential of the input node corresponds to the signal carriers accumulated by the photoelectric conversion layer during the third period, the magnitude relationship is in the first relationship, the second period is a period between the first period and the third period, and

the output control unit sets a potential range of the output node in the second period to be smaller than each of a potential range of the output node in the first period and a potential range of the output node in the third period, or the output control unit puts the amplification unit into a non-operating state in at least a part of the second period.

2. The photoelectric conversion apparatus according to claim 1, wherein

the magnitude relationship is the first relationship in the third period during which the photoelectric conversion layer accumulates the signal carriers while the second electrode is applied with the first potential by the driving unit.

3. The photoelectric conversion apparatus according to claim 1, further comprising:

a current source connected to the signal line; and

a selection transistor, wherein

the amplification unit is an amplification transistor,

an input node of the amplification transistor is the input node of the amplification unit,

a current is supplied from the current source to the amplification transistor when the selection transistor is put into a conductive state, and

the selection transistor is the output control unit that puts an electric path between the amplification transistor and the signal line into a non-conductive state in at least a part of the second period to put the amplification transistor into the non-operating state.

4. The photoelectric conversion apparatus according to claim 1, further comprising:

a current source connected to the signal line; and

a switch that switches a conductive state and a non-conductive state of an electric path between the current source and the amplification unit, wherein

the amplification unit is an amplification transistor, and

a current is supplied from the current source to the amplification transistor when the switch is put into a conductive state, and the switch is the output control unit that puts the electric path between the current source and the amplification transistor into the non-conductive state in at least a part of the second period to put the amplification transistor into the non-operating state.

5. The photoelectric conversion apparatus according to claim 1, wherein

the photoelectric conversion unit further includes a current source connected to the signal line and a potential supply unit that supplies a potential to the signal line,

the amplification unit is an amplification transistor, and

the potential supply unit is the output control unit that supplies the potential to the signal line in at least a part of the second period to set an amplitude of a signal output to the signal line to be smaller as compared with a case where the amplification transistor outputs a signal on the basis of the potential of the second electrode.

6. The photoelectric conversion apparatus according to claim 1, further comprising:

a capacitance element including a first node and a second node, wherein

the first node is connected to the second electrode,

a third potential is supplied to the second node in the first period, and

a fourth potential is supplied to the second node in the second period.

7. The photoelectric conversion apparatus according to claim 6, further comprising:

a second switch,

wherein the second switch is the output control unit that puts an electric path between a third node at which the second electrode is connected to the first node and an input node of the amplification unit into a non-conductive state in at least a part of the second period to set an amplitude of a signal output to the signal line to be smaller as compared with a case where the amplification unit outputs a signal based on the potential of the second electrode.

8. The photoelectric conversion apparatus according to claim 6, further comprising:

a plurality of photoelectric conversion units,

wherein the first node is commonly connected to each of the plurality of photoelectric conversion units.

9. The photoelectric conversion apparatus according to claim 8, wherein

electric paths between only a part of photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, and the optical signals are output from the second electrodes of the part of photoelectric conversion units to the amplification unit, and

thereafter, electric paths between all the photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, and a signal obtained by adding the optical signals output from the respective second electrodes of all the photoelectric conversion units to each other is output to the amplification unit.

10. The photoelectric conversion apparatus according to claim 9, wherein one micro lens is provided with respect to the plurality of photoelectric conversion units.

11. The photoelectric conversion apparatus according to claim 9, wherein

light is incident on the photoelectric conversion apparatus from an optical system,

lights ejected from mutually different exit pupils of the optical system are incident on each of the plurality of photoelectric conversion units,

thereafter, electric paths between all the photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, and a signal obtained by adding the optical signals output from the respective second electrodes of all the photoelectric conversion units to each other is output to the amplification unit.

12. The photoelectric conversion apparatus according to claim 8, further comprising:

a plurality of transfer units each provided so as to corresponding to each to the plurality of photoelectric conversion units,

each of the plurality of transfer units transfers the optical signal based on the signal carriers from the second electrode of each of the plurality of photoelectric conversion units to the amplification unit, and

the first node is connected to each of the plurality of photoelectric conversion units via each of the plurality of transfer units.

13. The photoelectric conversion apparatus according to claim 12, wherein

a capacitance value of the capacitance element is a first capacitance value in a case where only one transfer unit among the plurality of transfer units is on in a period during which the photoelectric conversion layer accumulates the signal carriers, and

the capacitance value of the capacitance element is a second capacitance value that is higher than the first capacitance value in a case where plural transfer units among the plurality of transfer units is on in the period during which the photoelectric conversion layer accumulates the signal carriers, the plurality of transfer units.

14. The photoelectric conversion apparatus according to claim 6, further comprising:

a capacitance potential supply unit,

wherein the capacitance potential supply unit supplies the third potential and the fourth potential to the second node.

15. The photoelectric conversion apparatus according to claim 8, further comprising:

a capacitance potential supply unit, wherein

the capacitance potential supply unit supplies the third potential and the fourth potential to the second node,

when the signal carriers are discharged from the photoelectric conversion layer, in a case where electric paths between N photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, the second node of the capacitance element is supplied with the fourth potential,

when the signal carriers are discharged from the photoelectric conversion layer, in a case where electric paths between M photoelectric conversion units that are more than the N photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, the capacitance potential supply unit supplies a fifth potential to the second node of the capacitance element, and

the fifth potential is a potential having a value higher than the fourth potential.

16. The photoelectric conversion apparatus according to claim 8, further comprising:

a capacitance potential supply unit, wherein

the capacitance potential supply unit supplies the third potential and the fourth potential to the second node,

when the signal carriers are discharged from the photoelectric conversion layer, in a case where electric paths between N photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, the second node of the capacitance element is supplied with the fourth potential,

when the signal carriers are discharged from the photoelectric conversion layer, in a case where electric paths between M photoelectric conversion units that are more than the N photoelectric conversion units among the plurality of photoelectric conversion units and the amplification unit are all put into a conductive state, the capacitance potential supply unit supplies a fifth potential to the second node of the capacitance element, and

the fifth potential is a potential having a value lower than the fourth potential.

17. The photoelectric conversion apparatus according to claim 1, wherein the photoelectric conversion layer includes a quantum dot.

18. The photoelectric conversion apparatus according to claim 1, wherein switching from either one of the first relationship and the second relationship to the other one of the first relationship and the second relationship is performed by changing the potential of the second electrode.

19. A photoelectric conversion system comprising:

a photoelectric conversion unit;

a signal line;

a reset unit having an input node, and an output node connected to a floating diffusion node;

a driving unit connected to the floating diffusion node;

an amplification unit having an input node, and an output node connected to the signal line; and

an output control unit, wherein the photoelectric conversion unit includes a first electrode, a second electrode, a photoelectric conversion layer that is arranged between the first electrode and the second electrode and accumulates signal carriers, and an insulating layer arranged between the photoelectric conversion layer and the second electrode,

a magnitude relationship between a potential applied to the first electrode and a first potential applied to the second electrode by the driving unit is a first relationship in a first period,

in the first period, the input node is supplied with a potential corresponding to the first potential, and the amplification unit outputs a signal corresponding to the potential of the input node, to the signal line,

in a second period, the magnitude relationship is in a second relationship that is opposite of the first relationship by changing a potential applied to the second electrode by the driving unit from the first potential to a second potential,

in a third period, during which the amplification unit outputs a signal corresponding to a potential of the input node, the potential of the input node corresponds to the signal carriers accumulated by the photoelectric conversion layer during the third period, the magnitude relationship is in the first relationship,

the second period is a period between the first period and the third period, and

the output control unit sets a potential range of the output node in the second period to be smaller than each of a potential range of the output node in the first period and a potential range of the output node in the third period, or the output control unit puts the amplification unit into a non-operating state in at least a part of the second period; and

an output signal processing unit configured to generate an image by processing a signal based on the optical signal output by the photoelectric conversion unit.

20. The photoelectric conversion system according to claim 19, wherein

the photoelectric conversion apparatus outputs both

a first signal based on the optical signal output from a part of the photoelectric conversion units among the plurality of photoelectric conversion units and

a second signal based on the optical signal outputs from all the photoelectric conversion units among the plurality of photoelectric conversion units to the output signal processing unit,

a phase difference is detected by using a difference between the first signal and the second signal, and

an image is generated by using the second signal.