Solid-state image pickup device with plural transfer structures to transfer charge to plural accumulation portions

• US 8,619,170 B2
• Filed: 08/03/2010
• Issued: 12/31/2013
• Est. Priority Date: 08/10/2009
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Mabuchi, Keiji
• Primary Examiner(s): Giles, Nicholas
• Assistant Examiner(s): Tissire, Abdelaaziz
• Application Number:
  US12/849,071
• Publication Number:
  US 20110032403A1
• Time in Patent Office: 1,246 Days
• Field of Search: 348320-322, 348/250, 348/230.1, 348/294, 348/296, 257/359
• US Class Current: 348/296
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/589 with different integration times, e.g. short and long exposures
• 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

A solid-state image pickup device includes a plurality of pixels and a scanning unit. Each pixel includes a photoelectric conversion element and a charge accumulation region. The scanning unit is configured to read a first signal from a charge accumulation region. The scanning unit is configured to read a second signal from the charge accumulation region. The first signal corresponds to an accumulation of signal charges during a first period, while the second signal corresponds to another accumulation of signal charges during a second period.

Claims

1. A solid-state image pickup device, comprising:

a pixel array unit in which unit pixels are arranged two-dimensionally in matrix, each unit pixel including (a) a photoelectric conversion part that accumulates a charge generated by electric conversion, (b) a first transfer structure that transfers said charge from said photoelectric conversion part to a first charge accumulation portion, (c) a second transfer structure that transfers said charge from said first charge accumulation portion to a second charge accumulation portion, (d) a readout structure that reads out a signal in response to said charge to a signal line and (e) a reset structure that resets said second charge accumulation portion; and

a row driving unit driving said unit pixel,

wherein,

(1) row driving unit is configured such that (a) said first transfer structure transfers said charge stored in said photoelectric conversion part during a first accumulation period to said first charge accumulation portion, (b) said second transfer structure and said readout structure read out a first signal to said signal line in response to said charge of said first charge accumulation portion, and then (c) said first transfer structure, said second transfer structure, and said readout structure read out a second signal to said signal line in response to said charge of said photoelectric conversion part during a second accumulation period,

(2) light is incident on said photoelectric conversion part through a mechanical shutter,

(3) said row driving unit resets said photoelectric conversion parts of all of said unit pixels simultaneously in an open state of said mechanical shutter,

(4) said first transfer structure transfers said charges of said photoelectric conversion parts to said first charge accumulation portions in all of said unit pixels simultaneously,

(5) said unit pixels in said pixel array unit are selected from each row in order in a close state of said mechanical shutter,

(6) said first signal is read to said signal line by said second transfer structure and said readout structure, and

(7) said second signal is read to said signal line by said first transfer structure, said second transfer structure, and said readout structure, while scanning.

2. The solid-state image pickup device according to claim 1, wherein a period from simultaneously resetting all of said pixels to transferring to said first charge accumulation portions simultaneously in all of said pixels is longer than a subsequent period of closing said mechanical shutter.

3. The solid-state image pickup device according to claim 1, wherein a synthetic processing section that performs synthetic processing of said first signal and said second signal which are output through said signal line.

4. The solid-state image pickup device according to claim 3, wherein:

said synthetic processing section employs said second signal×

α

when said first signal is at a saturation level or not less than a reference level near said saturation level, and employs said first signal when said first signal is not more than said reference level; and

said α

is a sensitivity ratio between said first signal and said second signal.

5. The solid-state image pickup device according to claim 3, wherein said synthetic processing part performs weighted average processing on said first signal and a signal obtained by said second signal×

α

when said first signal is not more than a saturation level or a first reference level near said saturation level or is not less than a second reference level which is smaller than said first reference level.

6. The solid-state image pickup device according to claim 5, wherein said synthetic processing section performs weighted average processing by arithmetic calculation of said first signal×

β

+said second signal×

α

×

(1−

β

) wherein β

is a coefficient.

7. A solid-state image pickup device, comprising:

a pixel array unit in which unit pixels are arranged two-dimensionally in matrix, each unit pixel including (a) a photoelectric conversion part that accumulates a charge generated by electric conversion, (b) a first transfer structure that transfers said charge from said photoelectric conversion part to a first charge accumulation portion, (c) a second transfer structure that transfers said charge from said first charge accumulation portion to a second charge accumulation portion, (d) a readout structure that reads out a signal in response to said charge to a signal line and (e) a reset structure that resets said second charge accumulation portion; and

a row driving unit driving said unit pixel,

wherein,

(1) said row driving unit is configured such that (a) said first transfer structure transfers said charge stored in said photoelectric conversion part during a first accumulation period to said first charge accumulation portion, (b) said second transfer structure and said readout structure read out a first signal to said signal line in response to said charge of said first charge accumulation portion, and then (c) said first transfer structure, said second transfer structure, and said readout structure read out a second signal to said signal line in response to said charge of said photoelectric conversion part during a second accumulation period;

(2) said row driving unit scans (a) a first shutter row that resets said photoelectric conversion part, (b) a second shutter row that transmits said charge of said photoelectric conversion part to said first charge accumulation portion by said first transfer structure, and (c) a readout row that reads said first signal to said signal line by said second transfer structure and said readout structure and reads a second signal to said signal line by said first transfer structure, said second transfer structure, and said readout structure;

(3) said first shutter row, said second shutter row, and said readout row are scanned in order while a period from timing of scanning said first shutter row to timing of scanning said second shutter row is different from a period from timing of scanning said second shutter row to timing of scanning said readout row

(4) said synthetic processing section employs said second signal×

α

when said first signal is at a saturation level or not less than a reference level near said saturation level, and employs said first signal when said first signal is not more than said reference level; and

(5) said α

is a sensitivity ratio between said first signal and said second signal.

8. The solid-state image pickup device according to claim 7, wherein said synthetic processing part performs weighted average processing on said first signal and a signal obtained by said second signal×

α

when said first signal is not more than a saturation level or a first reference level near said saturation level or is not less than a second reference level which is smaller than said first reference level.

9. The solid-state image pickup device according to claim 8, wherein said synthetic processing section performs weighted average processing by arithmetic calculation of said first signal×

β

+said second signal×

α

×

(1−

β

) wherein β

is a coefficient.