WO2017187975A1

WO2017187975A1 - Solid-state imaging element, driving method, and electronic device

Info

Publication number: WO2017187975A1
Application number: PCT/JP2017/014894
Authority: WO
Inventors: 俊超杉田; 信塚本; 将也五十嵐
Original assignee: ソニー株式会社
Priority date: 2016-04-26
Filing date: 2017-04-12
Publication date: 2017-11-02
Also published as: JP2017199993A

Abstract

This disclosure relates to a solid-state imaging element, a driving method, and an electronic device which allow avoidance of reduction in image quality. When a read operation for reading a pixel signal from a pixel in an effective pixel area is being performed regarding one image captured in a driving method for sequentially capturing two images within a one-frame time, driving is controlled such that regarding the other image, the row address of the pixel to be subjected to the read operation is jumped by a predetermined number of rows or less. This technology is applicable, for example, to a CMOS image sensor.

Description

Solid-state imaging device, driving method, and electronic apparatus

The present disclosure relates to a solid-state imaging device, a driving method, and an electronic device, and more particularly, to a solid-state imaging device, a driving method, and an electronic device that can avoid deterioration in image quality.

Conventionally, in an electronic device having an imaging function such as a digital still camera or a digital video camera, for example, a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is used. The solid-state imaging device has a pixel in which a photodiode that performs photoelectric conversion and a plurality of transistors are combined, and outputs a pixel signal that is output from a plurality of pixels arranged on an image plane on which an object image is formed. Based on this, an image is constructed.

In such a solid-state imaging device, for example, a high dynamic range (HDR) image with a wide dynamic range can be captured by performing multiple exposure driving for sequentially capturing multiple images within one frame time. .

Further, in Patent Document 1, as a driving method for realizing more diverse data output, for example, each pixel of a column of a pixel array is divided into a plurality of systems, and AD (Analog-to-digital) conversion processing of pixel signals is performed in a system. A driving method that is switched every time is disclosed.

JP 2013-55589 A

By the way, when the multiple exposure driving as described above and the driving method of switching the AD conversion processing of the pixel signal for each system are combined, when the row address for performing the read operation for reading the pixel signal from the pixel greatly changes, In some cases, horizontal stripes appear in the image and the image quality deteriorates.

The present disclosure has been made in view of such a situation, and is intended to avoid a deterioration in image quality.

In the solid-state imaging device according to one aspect of the present disclosure, a plurality of pixels are arranged in a matrix, and among the plurality of pixels, effective pixels that are pixels that output pixel signals used for image construction are arranged. A pixel provided with an ineffective pixel area, and an ineffective pixel area disposed in at least one of an upper side and a lower side in a vertical direction with respect to the effective pixel area and in which an ineffective pixel that is different from the effective pixel is arranged A first driving method for sequentially outputting a plurality of images within one frame time by outputting a driving signal for driving the region and the pixels arranged in the pixel region for each row; and one column A second driving method is performed in which the pixels arranged in a plurality of systems are divided into a plurality of systems, and conversion processing for converting the pixel signals output from the pixels into digital signals is switched for each system and performed in parallel. A drive control circuit that controls the drive of the pixel, and the drive control circuit includes the effective pixel for any one of the plurality of images picked up in the first drive method. When performing a read operation for reading a pixel signal from the pixels in the region, the drive is controlled so that the jump of the row address of the pixel targeted for the read operation is less than a predetermined number of rows for the other image .

In the driving method according to one aspect of the present disclosure, a plurality of pixels are arranged in a matrix, and among the plurality of pixels, effective pixels that are pixels that output pixel signals used for image construction are arranged. A pixel area provided with an effective pixel area and an ineffective pixel area that is disposed at least one above and below in the vertical direction with respect to the effective pixel area and in which an invalid pixel that is different from the effective pixel is disposed A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row, and sequentially capturing a plurality of images within one frame time, and one column A combination of a second driving method in which the pixels to be arranged are divided into a plurality of systems, and conversion processing for converting pixel signals output from the pixels into digital signals is switched for each system in parallel. A solid-state imaging device comprising: a drive control circuit that controls the drive of the pixel, wherein the drive control circuit includes any one of the plurality of images picked up by the first drive method. When a read operation for reading out a pixel signal from the pixel in the effective pixel region is performed for the image, a jump of a row address of the pixel targeted for the read operation for another image is equal to or less than a predetermined number of rows. The step of controlling the drive is included.

In an electronic device according to an aspect of the present disclosure, a plurality of pixels are arranged in a matrix, and among the plurality of pixels, effective pixels that are pixels that output pixel signals used for image construction are arranged. A pixel area provided with an effective pixel area and an ineffective pixel area that is disposed at least one above and below in the vertical direction with respect to the effective pixel area and in which an invalid pixel that is different from the effective pixel is disposed A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row, and sequentially capturing a plurality of images within one frame time, and one column A combination of a second driving method in which the pixels to be arranged are divided into a plurality of systems, and conversion processing for converting pixel signals output from the pixels into digital signals is switched for each system in parallel. A driving control circuit that controls driving of the pixels, and the driving control circuit includes the effective pixel region for any one of the plurality of images picked up by the first driving method. When performing a read operation for reading a pixel signal from the pixel, the solid state is controlled so that the jump of the row address of the pixel targeted for the read operation is not more than a predetermined number of rows for the other image. An image sensor is provided.

In one aspect of the present disclosure, when performing a read operation of reading a pixel signal from a pixel in an effective pixel region for any one of a plurality of images captured in the first driving method, The drive is controlled so that the jump of the row address of the pixel that is the target of the read operation is less than or equal to the predetermined number of rows.

According to one aspect of the present disclosure, it is possible to avoid a reduction in image quality.

It is a block diagram showing an example of composition of an embodiment of an image sensor to which this art is applied. It is a figure explaining the exposure drive which images two images sequentially within one frame time. It is a figure which shows the output image of image data. It is a figure explaining selection of a pixel in pipeline drive. It is a figure explaining the read-out period in pipeline drive. It is a figure explaining the conventional drive method. It is a figure explaining the drive method in an image sensor. 3 is a flowchart illustrating a method for driving an image sensor. It is a block diagram showing an example of composition of an embodiment of an imaging device to which this art is applied. It is a figure which shows the usage example which uses an image sensor.

Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

FIG. 1 is a block diagram illustrating a configuration example of an embodiment of an image sensor to which the present technology is applied.

As shown in FIG. 1, the image sensor 11 includes a pixel region 12, a vertical drive circuit 13, a column signal processing circuit 14, a horizontal drive circuit 15, an output circuit 16, and a control circuit 17.

The pixel region 12 is a light receiving surface that receives light collected by an optical system (not shown). In the pixel region 12, a plurality of pixels (pixels 31 in FIG. 4 described later) are arranged in a matrix, and each pixel is connected to the vertical drive circuit 13 for each row through a horizontal signal line. The column signal processing circuit 14 is connected to each column via the vertical signal line.

In the pixel area 12, an effective pixel area 21, an optical black (OPB) area 22, and dummy areas 23-1 and 23-2 are arranged. The effective pixel region 21 is disposed at the center of the pixel region 12, and the optical black region 22 is disposed below the effective pixel region 21 in the vertical direction. The dummy area 23-1 is disposed below the optical black area 22 in the vertical direction, and the dummy area 23-2 is disposed above the effective pixel area 21 in the vertical direction.

The effective pixel region 21 includes a plurality of pixels that output pixel signals in accordance with a drive signal supplied from the vertical drive circuit 13, and each of the plurality of pixels disposed in the effective pixel region 21 receives the amount of light received. A pixel signal of a level corresponding to the output is output. Pixel signals output from a plurality of pixels arranged in the effective pixel area 21 are used to construct an image of a subject that forms an image in the effective pixel area 21. That is, the pixels arranged in the effective pixel area 21 are effective pixels that output pixel signals used for image construction.

In the optical black area 22, pixels that are covered and shielded by the light shielding film are arranged, and the pixels arranged in the optical black area 22 output a pixel signal that is used as a reference for the optical black level. . In the dummy areas 23-1 and 23-2, dummy pixels that are driven in the same manner as the pixels arranged in the effective pixel area 21 and output pixel signals that are not used for image construction are arranged. In other words, the pixels arranged in the optical black region 22 and the dummy regions 23-1 and 23-2 are invalid pixels that are not directly used for image construction, unlike the effective pixels.

The vertical drive circuit 13 sequentially outputs a drive signal for driving (transferring, selecting, resetting, etc.) each pixel through a horizontal signal line for each row of a plurality of pixels arranged in the pixel region 12. To supply.

The column signal processing circuit 14 performs AD conversion of a pixel signal by performing CDS (Correlated Double Sampling) processing on a pixel signal output from a plurality of pixels via a vertical signal line. Remove reset noise.

The horizontal drive circuit 15 sequentially supplies a drive signal for outputting a pixel signal from the column signal processing circuit 14 to the data output signal line to the column signal processing circuit 14 for each column of the plurality of pixels arranged in the pixel region 12. Supply.

The output circuit 16 amplifies the pixel signal supplied from the column signal processing circuit 14 via the data output signal line at a timing according to the driving signal of the horizontal driving circuit 15 and outputs the amplified pixel signal to the subsequent signal processing circuit.

The control circuit 17 controls driving of each block by, for example, generating and supplying a clock signal according to the driving cycle of each block of the image sensor 11. For example, the control circuit 17 performs control to select one of the

pixels

31a and 31b as a target for AD conversion of the pixel signal by switching connection by

switches

41a and 41b shown in FIG. 4 to be described later.

In the imaging device 11 configured as described above, for example, color filters that transmit red, green, and blue light are arranged for each pixel according to a so-called Bayer array, and each pixel has a light amount of light of each color. A corresponding pixel signal is output. In addition, the imaging device 11 has a back surface structure in which a semiconductor substrate on which a photodiode constituting a pixel is formed is thinned, a wiring layer is stacked on the surface of the semiconductor substrate, and light is incident from the back surface side of the semiconductor substrate. Can be adopted.

Further, the image sensor 11 can perform a plurality of exposure driving operations such that a plurality of images are sequentially captured within one frame time. For example, the image sensor 11 performs exposure driving so as to sequentially capture two images with different exposure times, and combines the two images to capture an HDR image with a wide dynamic range. .

Referring to FIG. 2, exposure driving for sequentially capturing two images within one frame time will be described.

In FIG. 2, the horizontal direction represents the timing for driving the pixels, and the vertical direction represents the row addresses of the pixels arranged in the effective pixel region 21. In the image sensor 11, the pixels are driven by the rolling shutter method for each frame in accordance with the vertical synchronization signal (V） sync). In one frame, the first (first) exposure is referred to as primary, and the second exposure is referred to as secondary. For example, when an HDR image is captured by the image sensor 11, long exposure is performed at the primary and short exposure is performed at the secondary.

As shown in FIG. 2, first, a primary pre-shutter operation (Pre-SH) is performed, and after the charge remaining in the photodiode of the pixel after imaging one frame before is discharged, the shutter operation (SH) Is started, and accumulation of charge for a long time exposure is started. Then, at the timing when the exposure time of the long exposure has elapsed, a read operation (RD) for reading out a pixel signal at a level corresponding to the charge accumulated in the photodiode is performed.

After that, when a certain time difference (read offset) elapses, secondary pre-shutter operation (Pre SH) is performed, and the charge accumulated in the photodiode of the pixel during the lead offset is discharged, then the shutter operation (SH) is performed, and accumulation of electric charges for short-time exposure is started. Then, at the timing when the exposure time of short exposure has elapsed, a read operation (RD) for reading out a pixel signal at a level corresponding to the charge accumulated in the photodiode is performed.

The image sensor 11 outputs primary image data that is image data of the primary image and secondary image data that is image data of the secondary image by performing such exposure driving.

FIG. 3 shows an output image of the image data output from the image sensor 11.

As shown in FIG. 3, in the output image of image data, a primary vertical blank is arranged below the primary image data, and a secondary vertical blank is arranged above the secondary image data. The primary image data and the primary vertical blank, the secondary image data and the secondary vertical blank are arranged next to each other, and the common vertical blank is arranged below them.

The primary image data is data based on a pixel signal output from the pixel during the primary exposure, and the secondary image data is a pixel signal output from the pixel during the secondary exposure. It is data based on.

In the primary vertical blank, data based on pixel signals output during a period in which the primary exposure is completed and the secondary exposure is performed is arranged. In the secondary vertical blank, data based on a pixel signal output during a period in which the primary exposure is performed before the secondary exposure starts is arranged. In the common vertical blank, data based on pixel signals output during a period in which primary and secondary exposure are not performed is arranged. For example, in the primary vertical blank, the secondary vertical blank, and the common vertical blank, data based on the pixel signal output from the pixel in the optical black area 22 or the dummy area 23 in FIG. It is discarded without being used to construct.

Further, in the image sensor 11, the column signal processing circuit 14 performs AD conversion of the pixel signal at the reset level and AD conversion of the pixel signal at the signal level, and the reset noise is removed based on the difference between them. it can. In general, a driving method is used in which AD conversion of a pixel signal at a reset level and AD conversion of a pixel signal at a signal level are continuously performed for each pixel arranged in one column.

On the other hand, in the image sensor 11, the pixels arranged in one column are divided into two systems, and the AD conversion of the reset level pixel signal output from the pixel and the AD conversion of the signal level pixel signal are performed in the system. It is possible to adopt a driving method in which each is switched and alternately performed in parallel. For example, while the settling of one pixel of the two systems is being performed, the pixel signal of the other pixel is read as a whole by performing a drive that performs AD conversion on the pixel signal of the other pixel. The period can be shortened. Such a driving method is hereinafter referred to as pipeline driving as appropriate.

Pipeline driving will be described with reference to FIGS.

As shown in FIG. 4, in the pipeline driving, the pixel 31a and the pixel 31b are alternately selected, and the pixel signal is AD-converted. FIG. 4 shows an example in which the pixels 31 are alternately selected for each pixel sharing unit 32 sharing the pixel circuit by the eight pixels 31, and two vertical lines corresponding to the two systems are shown.

Signal lines

33a and 33b are provided.

Further, the pixels 31a included in the pixel sharing unit 32a are connected to the constant current source 34a and the column signal processing circuit 14 through the vertical signal line 33a. Similarly, the pixel 31b included in the pixel sharing unit 32b is connected to the constant current source 34b and the column signal processing circuit 14 through the vertical signal line 33b.

In the column signal processing circuit 14, the vertical signal line 33a is connected to one input terminal of the comparator 44 via the switch 41a and the capacitor 42a, and the vertical signal line 33b is connected via the switch 41b and the capacitor 42b. Is done. As described above, the switch 41a and the switch 41b serve as a selection unit that switches the connection between the vertical signal line 33a and the vertical signal line 33b and one input terminal of the comparator 44 and selects a target for AD conversion of the pixel signal. Used.

The other input terminal of the comparator 44 receives a reference signal (a ramp signal having a waveform in which the potential drops at a constant gradient) that is referred to when the pixel signal is AD-converted via the capacitor 43. . The output terminal of the comparator 44 is connected to the counter 45, and the counter 45 counts the comparison result between the pixel signal and the reference signal by the comparator 44, whereby the pixel signal is AD converted.

On the left side of FIG. 4, the pixel 31 a is selected, that is, the switch 41 a is turned on and the switch 41 b is turned off, and is output from the pixel 31 a connected to the comparator 44. A state in which the pixel signal is AD converted is shown. On the other hand, on the right side of FIG. 4, the pixel 31 b is selected, that is, the switch 41 a is turned off and the switch 41 b is turned on, and is output from the pixel 31 b connected to the comparator 44. A state in which the pixel signal is AD converted is shown.

Thus, by alternately selecting the pixel 31a and the pixel 31b, the pixel signal input to the comparator 44 is switched, and the pixel signal can be alternately AD-converted between the pixel 31a and the pixel 31b. .

With reference to FIG. 5, the readout period of the pixel 31a and the pixel 31b will be described.

The upper side of FIG. 5 shows a first readout period for reading out a pixel signal from the pixel 31a, and the lower side of FIG. 5 shows a second readout period for reading out a pixel signal from the pixel 31b. .

First, the pixel 31a is reset and settled. Thereafter, as shown on the left side of FIG. 4, the pixel 31a is selected, and the reset and settling of the pixel 31b is performed in parallel with the pixel signal of the reset level being read from the pixel 31a and AD-converted.

Then, when the AD conversion of the pixel signal at the reset level of the pixel 31a is completed, the pixel 31b is selected as shown on the right side of FIG. Thereafter, data obtained by AD conversion of the pixel signal at the reset level of the pixel 31a is held, and the pixel signal at the reset level of the pixel 31b is transferred in parallel with the transfer of the charge accumulated in the photodiode of the pixel 31a. Are read out and AD converted.

In parallel with the settling for the pixel 31a, data obtained by AD-converting the pixel signal at the reset level of the pixel 31b is held, and the charge accumulated in the photodiode of the pixel 31b is transferred.

Thereafter, as shown on the left side of FIG. 4, the pixel 31a is selected, and the settling is performed on the pixel 31b in parallel with the AD conversion of the pixel signal of the signal level of the pixel 31a. When the pixel signal at the signal level of the pixel 31a is read and AD conversion is completed, the pixel 31b is selected as shown on the right side of FIG. Thereafter, in parallel with holding the data obtained by AD converting the pixel signal at the signal level of the pixel 31a, the pixel signal at the signal level of the pixel 31b is read and AD converted.

As described above, in the pipeline driving, the pixel 31a and the pixel 31b are alternately driven so that AD conversion of the pixel signal is performed, and the pixel signal reading period of the entire image sensor 11 can be shortened.

By the way, when the multiple exposure driving as described with reference to FIG. 2 and the pipeline driving as described with reference to FIGS. 4 and 5 are combined, horizontal stripes are generated in the image. The image quality sometimes deteriorated.

For example, as shown in FIG. 6, conventionally, when reading out a pixel signal from the optical black region 22, the row address of the pixel that performs the read operation is greatly jumped from the dummy region 23-1 to the optical black region 22. Driving is performed. Further, when reading of the pixel signal from the effective pixel area 21 is started, the address jump of the row address of the pixel that performs the read operation from a predetermined line of the optical black area 22 to the first line of the effective pixel area 21 is greatly jumped. Is done. Further, when the reading of the pixel signal from the effective pixel area 21 is finished, the address jump of the row address of the pixel that performs the read operation from the last line of the effective pixel area 21 to a predetermined line of the dummy area 23-2 is greatly jumped. Driving is performed.

For example, at the timing T1 when the read operation of the optical black area 22 is started in the primary, no horizontal stripes are generated. On the other hand, when a large address jump is performed in the secondary at the timing T2 when the read operation of the optical black area 22 is started in the secondary, the horizontal stripes appear in the row that is the target of the read operation of the optical black area 22 in the primary. Will occur. Further, when a large address jump is performed in the primary at the timing T3 at which the read operation of the effective pixel region 21 is started in the primary, a horizontal stripe occurs in the row that is the target of the read operation in the optical black region 22 in the secondary. End up. As described above, the pixel signal read from the optical black region 22 is used as a black level reference, and if this reference fluctuates due to noise (horizontal stripes), the image quality may be adversely affected. It is not preferable because there is.

In addition, when a large address jump is performed in the secondary at the timing T4 when the read operation of the effective pixel region 21 is started in the secondary, a horizontal stripe occurs in the row that is the target of the read operation of the effective pixel region 21 in the primary. End up. Furthermore, when a large address jump is performed in the primary at the timing T5 when the read operation of the effective pixel region 21 is finished in the primary, a horizontal stripe occurs in the row that is the target of the read operation of the effective pixel region 21 in the secondary. End up.

Note that the timing T7 at which the address jump from the dummy area 23-2 to the dummy area 23-1 is performed during the blanking period after the read operation of the secondary effective pixel area 21 is completed, and therefore the image quality is affected. There is no effect.

For example, a voltage drop (IR drop) generated in the pixel power source used for driving the pixel 31 between the AD conversion of the pixel signal at the reset level and the AD conversion of the pixel signal at the signal level due to the address jump of the row address. As the degree of change changes, horizontal stripes appear in the image.

Generally, when a read operation for reading a pixel signal from the pixel 31 is performed, a voltage drop occurs in a row that is a target of the read operation in the pixel power supply. Further, if the interval between the row where the read operation is performed in the primary and the row where the read operation is performed in the secondary is constant, the distribution of the voltage drop generated in the pixel power supply is constant. Will not have a major impact. However, if the interval between the row in which the read operation is performed in the primary and the row in which the read operation is performed in the secondary changes greatly, the distribution of the voltage drop generated in the pixel power supply changes greatly. Therefore, as described above, when driving is performed so that the address jump of the row address of the pixel 31 that performs the read operation is greatly performed, the distribution of the voltage drop generated in the pixel power supply changes greatly.

Therefore, for example, when a read operation of the effective pixel region 21 is performed in the secondary and a large address jump is performed in the primary (timing T5), the distribution of the voltage drop generated in the pixel power supply greatly varies. The influence of this fluctuation wraps around as a noise in the pixel signal output from the pixel 31 in the row in which the secondary read operation is performed, resulting in a horizontal stripe in the image.

At this time, the amount of noise with respect to the pixel signal has a magnitude that depends on the number of rows that jump to the address of the row address (the amount of change in the row address). It will be big. Even if the relationship between the primary and secondary is reversed, similarly, horizontal stripes occur in the image.

Therefore, when one of the primary and secondary is reading a pixel signal from the effective pixel region 21, the number of rows in which the address jump of the row address is performed so that the other address jump does not cause a horizontal stripe (not to be noticeable). The occurrence of lateral stripes can be suppressed by setting the value to a predetermined line or less. That is, by reducing the degree of change in the distribution of the voltage drop generated in the pixel power supply, the amount of noise with respect to the pixel signal can be reduced, and the horizontal stripes appearing in the image can be suppressed.

Therefore, the image sensor 11 employs a driving method in which when one of the primary and secondary is reading a pixel signal from the effective pixel region 21, the other address jump is performed with a predetermined number of rows or less. Thereby, generation | occurrence | production to a horizontal stripe as mentioned above can be suppressed, and the fall of an image quality can be avoided.

With reference to FIG. 7, a driving method in the image sensor 11 will be described.

Before the imaging device 11 starts imaging one frame, the pixels 31 in a predetermined row in the dummy area 23-1 are driven. In the following description, the row access is performed for a predetermined period before the read operation for the optical black area 22 and the effective pixel area 21 is started and for a predetermined period after the read operation for the effective pixel area 21 is ended. This is called a transition period.

When the imaging device 11 starts imaging one frame, the vertical drive circuit 13 first starts in the row access transition period P1 before the timing T1 at which the read operation for the pixel 31 in the optical black region 22 is started for the primary. Then, a read operation is performed on the pixels 31 in the dummy area 23-1 by repeating an address jump with a small width equal to or less than a predetermined number of rows to the extent that the above-described horizontal stripe does not occur (hereinafter referred to as thinning access as appropriate). .

Then, after starting the read operation for the pixel 31 in the optical black region 22 for the primary at the timing T1, the vertical drive circuit 13 before the timing T2 when the read operation for the pixel 31 in the optical black region 22 is started for the secondary. In the row access transition period P2, a read operation is performed by thinning access to the pixels 31 in the dummy area 23-1. Thus, by avoiding a large address jump from being performed at the secondary at the timing T2 shown in FIG. 6, it is possible to suppress the horizontal stripes occurring at the primary at the timing T2.

Subsequently, the vertical drive circuit 13 performs the read operation by thinning access to the pixels 31 in the optical black region 22 in the row access transition period P3 before the timing T3 when the read operation for the pixels 31 in the effective pixel region 21 is started for the primary. I do. Similarly, the vertical drive circuit 13 performs the read operation by thinning access to the pixels 31 in the optical black region 22 in the row access transition period P4 before the timing T4 when the read operation for the pixels 31 in the effective pixel region 21 is started for the secondary. I do. Accordingly, it is possible to avoid a large address jump at the timings T3 and T4 and to suppress the horizontal stripes generated at the respective timings.

Further, the vertical drive circuit 13 performs a read operation by thinning access to the pixels 31 in the dummy region 23-2 in the row access transition period P5 after the timing T5 when the read operation of the effective pixel region 21 is finished in the primary. In this way, by avoiding a large address jump at the secondary at the timing T5 shown in FIG. 6, it is possible to suppress the horizontal stripes that occur at the secondary at the timing T5.

Similarly, the vertical drive circuit 13 performs the read operation by thinning access to the pixels 31 in the dummy region 23-2 in the row access transition period P6 after the timing T6 when the read operation of the effective pixel region 21 is finished in the secondary. I do. Thereafter, for both the primary and secondary, an address jump from the dummy area 23-2 to the dummy area 23-1 is performed at a timing T7 in a blanking period when the read operation for the pixel 31 in the effective pixel area 21 is not performed. .

As described above, the image pickup device 11 controls the occurrence of the horizontal stripe as described above by controlling the address jump of the row address of the pixel that performs the read operation at an appropriate timing, thereby reducing the image quality. It can be avoided. The pixel signal read from the pixel 31 by the thinning access is discarded without being used for image construction.

Next, FIG. 8 is a flowchart for explaining a driving method when one image is captured by the image sensor 11.

For example, the image sensor 11 captures an image for each frame in accordance with the vertical synchronization signal (V sync), and as shown in FIG. 7, during the blanking period, driving of the pixels 31 in a predetermined row in the dummy region 23-1 is performed. Has been done. In step S11, the vertical drive circuit 13 performs thinning access to the pixels 31 in the dummy area 23-1 for the row access transition period P1 before the timing T1 when the read operation of the primary optical black area 22 is started. Read operation is performed.

Then, at the timing T1 when the read operation of the primary optical black region 22 is started, the vertical drive circuit 13 performs a read operation on the pixels 31 in the optical black region 22 for the primary in step S12.

In step S13, the vertical drive circuit 13 reads the pixel 31 in the dummy area 23-1 by thinning access for the row access transition period P2 before the timing T2 when the read operation of the secondary optical black area 22 is started. Perform the action.

Then, at the timing T2 when the read operation of the secondary optical black region 22 is started, the vertical drive circuit 13 performs a read operation on the pixel 31 in the optical black region 22 for the secondary in step S14.

In step S15, the vertical drive circuit 13 performs a read operation by thinning access to the pixels 31 in the optical black region 22 for the row access transition period P3 before the timing T3 when the read operation of the primary effective pixel region 21 is started. I do.

The vertical drive circuit 13 performs a read operation on the pixels 31 in the effective pixel region 21 for the primary in step S16 at the timing T3 when the read operation on the primary effective pixel region 21 is started.

In step S <b> 17, the vertical drive circuit 13 performs a read operation by thinning access to the pixels 31 in the optical black region 22 for the row access transition period P <b> 4 before the timing T <b> 4 when the read operation of the secondary effective pixel region 21 is started. I do.

The vertical drive circuit 13 performs a read operation on the pixels 31 in the effective pixel region 21 for the secondary in step S18 at the timing T4 when the read operation of the secondary effective pixel region 21 is started.

Thereafter, the read operation for the pixels 31 in the effective pixel region 21 is performed row by row for both the primary and secondary, and when the timing T5 at which the read operation of the effective pixel region 21 is completed in the primary, the process proceeds to step S19. In step S19, the vertical drive circuit 13 performs a read operation by thinning access on the pixels 31 in the dummy region 23-2 in the row access transition period P5 after the timing T5.

Similarly, when the timing T6 at which the reading operation of the effective pixel region 21 is finished in the secondary is reached, in step S20, the vertical drive circuit 13 detects the pixels in the dummy region 23-2 in the row access transition period P6 after the timing T6. 31 is read by thinning access.

In step S21, the vertical drive circuit 13 jumps the read operation from the dummy area 23-2 to the dummy area 23-1 at the timing T7 after the timing T6 for both the primary and secondary.

After the process in step S21, the process is terminated, and the same process is repeated when the next frame starts to be imaged.

As described above, the image sensor 11 performs the read operation by the thinning access in the row access transition period, and performs the jump of the read operation from the dummy region 23-2 to the dummy region 23-1 to read the effective pixel region 21. By performing it during a blanking period in which no operation is performed, as described above, it is possible to suppress the horizontal streak generated in the image and avoid the deterioration of the image quality.

In the image pickup device 11, when one of the primary and secondary is reading a pixel signal from the effective pixel region 21, the address jump of the other read operation may be equal to or less than a predetermined number of rows. On the other hand, the read operation may be repeated. Further, the predetermined number of address jumps performed to such an extent that no horizontal stripes occur is, for example, preferably 100 lines or less, and more preferably 50 lines or less.

In the image sensor 11, the effective pixel area 21 provided in the pixel area 12 may be divided and used.

Note that the imaging device 11 as described above is applied to various electronic devices such as an imaging system such as a digital still camera and a digital video camera, a mobile phone having an imaging function, or other devices having an imaging function. can do.

FIG. 9 is a block diagram illustrating a configuration example of an imaging device mounted on an electronic device.

As shown in FIG. 9, the imaging apparatus 101 includes an optical system 102, an imaging element 103, a signal processing circuit 104, a monitor 105, and a memory 106, and can capture still images and moving images.

The optical system 102 includes one or more lenses, guides image light (incident light) from a subject to the image sensor 103, and forms an image on a light receiving surface (sensor unit) of the image sensor 103.

As the image sensor 103, the above-described image sensor 11 is applied. In the image sensor 103, electrons are accumulated for a certain period according to an image formed on the light receiving surface via the optical system 102. Then, a signal corresponding to the electrons accumulated in the image sensor 103 is supplied to the signal processing circuit 104.

The signal processing circuit 104 performs various signal processing on the pixel signal output from the image sensor 103. An image (image data) obtained by performing signal processing by the signal processing circuit 104 is supplied to the monitor 105 and displayed, or supplied to the memory 106 and stored (recorded).

In the imaging apparatus 101 configured as described above, by applying the imaging element 11 described above, for example, it is possible to capture a higher quality image while avoiding deterioration in image quality.

FIG. 10 is a diagram illustrating a usage example in which the above-described image sensor is used.

The image sensor described above can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-ray as follows.

・ Devices for taking images for viewing, such as digital cameras and mobile devices with camera functions ・ For safe driving such as automatic stop and recognition of the driver's condition, Devices used for traffic, such as in-vehicle sensors that capture the back, surroundings, and interiors of vehicles, surveillance cameras that monitor traveling vehicles and roads, and ranging sensors that measure distances between vehicles, etc. Equipment used for home appliances such as TVs, refrigerators, air conditioners, etc. to take pictures and operate the equipment according to the gestures ・ Endoscopes, equipment that performs blood vessel photography by receiving infrared light, etc. Equipment used for medical and health care ・ Security equipment such as security surveillance cameras and personal authentication cameras ・ Skin measuring instrument for photographing skin and scalp photography Such as a microscope to do beauty Equipment used for sports-Equipment used for sports such as action cameras and wearable cameras for sports applications-Used for agriculture such as cameras for monitoring the condition of fields and crops apparatus

In addition, this technique can also take the following structures.
(1)
An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A drive control circuit to control,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, the solid-state imaging device that controls the drive so that the jump of the row address of the pixel that is the target of the read operation for the other image is equal to or less than a predetermined number of rows.
(2)
A plurality of vertical signal lines provided for each of the systems;
A comparator that compares a pixel signal output from the pixel with a predetermined reference signal;
A selector that selects a pixel that is to be subjected to a conversion process for converting the pixel signal into a digital signal by switching connection between the vertical signal line for each of the plurality of systems and the input terminal of the comparator; The solid-state imaging device according to (1) above.
(3)
The solid-state imaging device according to (1) or (2), wherein a pixel signal output from the pixel driven so that a jump of a row address is performed by a predetermined number of rows or less by the drive control circuit is discarded.
(4)
The drive control circuit is a target of the read operation for the pixels arranged in the invalid pixel region in a predetermined period before the timing when the read operation for the pixels arranged in the effective pixel region is started. The solid-state imaging device according to any one of (1) to (3), wherein driving is controlled so that a jump of a row address is performed with a width equal to or less than a predetermined number of rows.
(5)
The drive control circuit is a target of the read operation for the pixels arranged in the invalid pixel region in a predetermined period after the timing when the read operation for the pixels arranged in the effective pixel region is completed. The solid-state imaging device according to any one of (1) to (4), wherein the driving is controlled so that the jump of the row address is performed with a width equal to or less than a predetermined number of rows.
(6)
The drive control circuit does not perform a read operation of reading a pixel signal from the pixels in the effective pixel region in any of the plurality of images captured in the first driving method. Sometimes, the drive is performed so that the row address of the pixel to be read is jumped from one of the invalid pixel regions arranged above and below in the vertical direction to the effective pixel region to the other. The solid-state imaging device according to any one of (1) to (5).
(7)
An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A driving control circuit for controlling the solid-state imaging device,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, the driving method includes a step of controlling the driving so that the jump of the row address of the pixel that is the target of the read operation for the other image is equal to or less than a predetermined number of rows.
(8)
An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A drive control circuit to control,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, an electronic device including a solid-state imaging device that controls driving so that a jump of a row address of the pixel that is a target of the read operation for another image is equal to or less than a predetermined number of rows.

Note that the present embodiment is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present disclosure.

11 Image sensor, 12 pixel area, 13 vertical drive circuit, 14 column signal processing circuit, 15 horizontal drive circuit, 16 output circuit, 17 control circuit, 21 effective pixel area, 22 optical black area, 23-1 and 23-2 dummy Area, 31 pixels, 32 pixel sharing units, 33 vertical signal lines, 34 constant current sources, 41 switches, 42 and 43 capacitors, 44 comparators, 45 counters

Claims

An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A drive control circuit to control,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, the solid-state imaging device that controls the drive so that the jump of the row address of the pixel that is the target of the read operation for the other image is equal to or less than a predetermined number of rows.
A plurality of vertical signal lines provided for each of the systems;
A comparator that compares a pixel signal output from the pixel with a predetermined reference signal;
A selector that selects a pixel that is to be subjected to a conversion process for converting the pixel signal into a digital signal by switching connection between the vertical signal line for each of the plurality of systems and the input terminal of the comparator; The solid-state imaging device according to claim 1.
The solid-state imaging device according to claim 1, wherein a pixel signal output from the pixel driven so that a jump of a row address is performed by a predetermined number of rows or less by the drive control circuit is discarded.
The drive control circuit is a target of the read operation for the pixels arranged in the invalid pixel region in a predetermined period before the timing when the read operation for the pixels arranged in the effective pixel region is started. The solid-state imaging device according to claim 1, wherein driving is controlled so that a jump of a row address is performed with a width equal to or less than a predetermined number of rows.
The drive control circuit is a target of the read operation for the pixels arranged in the invalid pixel region in a predetermined period after the timing when the read operation for the pixels arranged in the effective pixel region is completed. The solid-state imaging device according to claim 1, wherein driving is controlled so that a jump of a row address is performed with a width equal to or less than a predetermined number of rows.
The drive control circuit does not perform a read operation of reading a pixel signal from the pixels in the effective pixel region in any of the plurality of images captured in the first driving method. Sometimes, the drive is performed so that the row address of the pixel to be read is jumped from one of the invalid pixel regions arranged above and below in the vertical direction to the effective pixel region to the other. The solid-state imaging device according to claim 1 to be controlled.
An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A driving control circuit for controlling the solid-state imaging device,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, the driving method includes a step of controlling the driving so that the jump of the row address of the pixel that is the target of the read operation for the other image is equal to or less than a predetermined number of rows.
An effective pixel area in which a plurality of pixels are arranged in a matrix, and an effective pixel that is a pixel that outputs a pixel signal used to construct an image among the plurality of pixels, and the effective pixel area A pixel area provided with an invalid pixel area in which an invalid pixel that is the pixel different from the effective pixel is disposed at least one of the upper and lower sides in the vertical direction with respect to
A first driving method for outputting a driving signal for driving the pixels arranged in the pixel area for each row and sequentially capturing a plurality of images within one frame time, and arranged in one column The pixel is divided into a plurality of systems, and the pixel is driven by combining a second driving method in which conversion processing for converting a pixel signal output from the pixel into a digital signal is performed for each system in parallel. A drive control circuit to control,
When the drive control circuit performs a read operation of reading a pixel signal from the pixels in the effective pixel region for any one of the plurality of images picked up by the first driving method. In addition, an electronic device including a solid-state imaging device that controls driving so that a jump of a row address of the pixel that is a target of the read operation for another image is equal to or less than a predetermined number of rows.