Solid state imaging element, driving method of solid state imaging element, and electronic apparatus

Patent metadata

Field	Value
Publication number	US-9667894-B2
Application number	US-201314387511-A
Country	US
Kind code	B2
Filing date	Mar 21, 2013
Priority date	Mar 30, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A solid state imaging element including a drive circuit and a pixel unit with pixels arranged in a matrix form. The pixels include a photoelectric conversion element configured to convert light incident thereupon into a charge and to accumulate the charge, a charge holding unit connected to the photoelectric conversion element, and a floating diffusion region. The drive circuit transfers a first portion of the charge accumulated in the photoelectric conversion element to the charge holding unit and concurrently transfers a second portion of the charge accumulated in the photoelectric conversion element to the floating diffusion region. Electronic global shutter is realized by transferring charge from the photoelectric conversion elements of each of the pixels at substantially the same time.

First claim

The invention claimed is:

1. A solid state imaging element, comprising:
a drive circuit; and
a pixel unit, wherein the pixel unit comprises a plurality of pixels arranged in a matrix form, wherein each pixel of the plurality of the pixels includes:
a photoelectric conversion element configured to convert light incident thereupon into a charge and to accumulate the charge;
a charge holding unit connected to the photoelectric conversion element; and
a floating diffusion region connected to the charge holding unit,

wherein the drive circuit is configured to:
perform a first transfer operation for each pixel of the plurality of pixels, wherein the first transfer operation causes the charge holding unit to receive and hold a first portion of the charge accumulated in the photoelectric conversion element and concurrently causes the floating diffusion region to receive and hold a second portion of the charge accumulated in the photoelectric conversion element;
perform a global shutter operation that comprises:
begin respective charge accumulation periods for each pixel of the plurality of pixels at substantially same time by reset of the photoelectric conversion element of each pixel of the plurality of pixels at substantially the same time, and
end the respective accumulation periods for each pixel of the plurality of pixels at substantially the same time based on performance of the first transfer operation for each pixel of the plurality of pixels at substantially the same time;
perform a rolling readout operation that comprises read out, from each pixel of the plurality of pixels, respective data signals that correspond to the respective charges accumulated in the photoelectric conversion elements of the plurality of pixels; and
start the global shutter operation for an (n+1)-th imaging frame while the rolling readout operation for an n-th imaging frame is being performed.

2. The solid state imaging element of claim 1 , wherein the drive circuit is further configured to, after performance of the first transfer operation, read out a first data signal corresponding to a magnitude of the second portion of the charge accumulated in the photoelectric conversion element and subsequently read out a second data signal corresponding to a magnitude of the first portion of the charge accumulated in the photoelectric conversion element.

3. The solid state imaging element of claim 2 , wherein the drive circuit is further configured to, after read out of the first data signal corresponding to the magnitude of the second portion of the charge accumulated in the photoelectric conversion element and before read out of the second data signal corresponding to the magnitude of the first portion of the charge accumulated in the photoelectric conversion element:
reset the floating diffusion region;
read out a third data signal corresponding to a reset level of the floating diffusion region; and
perform a second transfer operation that causes the first portion of the charge accumulated in the photoelectric conversion element, which is held in the charge holding unit, to be transferred to the floating diffusion region.

4. The solid state imaging element of claim 3 , wherein the each of the plurality of pixels further comprises:
a reset transistor connected to the floating diffusion region and to a reset potential, wherein the reset transistor is configured to conduct when a reset signal is applied thereto; and
a selection transistor configured to output a fourth data signal to the drive circuit based on an application of a selection signal to the selection transistor, wherein the fourth data signal is based on a magnitude of a charge held in the floating diffusion region,
wherein the drive circuit is further configured to:
read out the first data signal corresponding to the magnitude of the second portion of the charge accumulated in the photoelectric conversion element by the application of the selection signal to the selection transistor based on the second portion of the charge accumulated in the photoelectric conversion element beinq held in the floating diffusion region;
reset the floating diffusion region by application of the reset signal to the reset transistor;
read out the third data signal corresponding to the reset level of the floating diffusion region by application of the selection signal to the selection transistor after reset of the floating diffusion region; and
read out the second data signal corresponding to the magnitude of the first portion of the charge accumulated in the photoelectric conversion element by application of the selection signal to the selection transistor based on the first portion of the charge accumulated in the photoelectric conversion element being held in the floating diffusion region.

5. The solid state imaging element of claim 1 ,
wherein the each pixel of the plurality of pixels includes a drain transistor connected to the photoelectric conversion element and to a drain potential,
wherein the drive circuit is further configured to reset the photoelectric conversion element based on the drain transistor being in a conducting state for a pulsed period, and
wherein a magnitude of a first potential barrier between the drain transistor in a non-conducting state and the photoelectric conversion element is smaller than a magnitude of a second potential barrier between the charge holding unit and the photoelectric conversion element.

6. The solid state imaging element of claim 1 ,
wherein the plurality of pixels are arranged in groups of N pixels, where N is an integer, and
wherein pixels that are included in a same group of the groups share one floating diffusion region in common, wherein the one floating diffusion region constitute respective floating diffusion regions included in each of the pixels that share the one floating diffusion in common.

7. A solid state imaging element, comprising:
a drive circuit; and
a pixel unit, wherein the pixel unit comprises a plurality of pixels arranged in a matrix form, wherein each pixel of the plurality of the pixels includes:
a photoelectric conversion element configured to convert light incident thereupon into a charge and to accumulate the charge;
a charge holding unit connected to the photoelectric conversion element; and
a floating diffusion region connected to the charge holding unit, wherein the plurality of pixels are arranged in groups of N pixels, where N is an integer, and
wherein pixels that are included in a same group of the groups share one floating diffusion region in common, wherein the one floating diffusion region constitute respective floating diffusion regions included in each of the pixels that share the one floating diffusion in common,

wherein the drive circuit is configured to:
perform a transfer operation for each pixel of the plurality of pixels, wherein the transfer operation causes the charge holding unit to receive and hold a first portion of the charge accumulated in the photoelectric conversion element and concurrently causes the floating diffusion region to receive and hold a second portion of the charge accumulated in the photoelectric conversion element;
perform a global shutter operation that comprises:
begin respective charge accumulation periods for each pixel of the plurality of pixels at substantially same time by reset of the photoelectric conversion element of each pixel of the plurality of pixels at substantially the same time, and
end the respective accumulation periods for each pixel of the plurality of pixels at substantially the same time based on performance of the transfer operation for each pixel of the plurality of pixels at substantially the same time;

perform a rolling readout operation that comprises read out, from each pi

Assignees

• Sony Corp

Inventors

• Mabuchi Keiji

Classifications

• H04N25/70

  SSIS architectures; Circuits associated therewith · CPC title

• H04N25/46

  by combining or binning pixels · CPC title

• H04N25/771 Primary

  comprising storage means other than floating diffusion · CPC title

• H04N25/713 Primary

  Transfer or readout registers; Split readout registers or multiple readout registers · CPC title

• H04N25/778

  comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself · CPC title