JP4921011B2 - Imaging apparatus and driving method thereof - Google Patents

Description

The present invention relates to an imaging device and a driving method thereof, in particular, regarding the imaging device and the driving method made it possible to reduce the disturbance noise.

  In an imaging device such as an electronic camera that records and reproduces a still image or a moving image captured by a solid-state imaging device such as a CCD or CMOS, which is commercially available, dark current noise generated by the imaging device or a small amount unique to the imaging device Degradation of image quality due to pixel defects such as scratches.

  With respect to such image quality degradation, the conventional imaging device reads and subtracts the noise component derived from the dark current and scratches described above for each pixel and the optical signal component obtained by exposing the imaging device. High-quality images can be obtained.

  However, in the conventional imaging apparatus, measures against image quality degradation due to disturbance noise are not taken, and image quality degradation may occur. Disturbance noise refers to noise caused by voltage fluctuations of the DC / DC converter that changes the voltage of the strobe and power supply circuit, noise caused by fluctuations in the power supply of the image sensor, noise caused by fluctuations in magnetism generated from motors that move the lens and diaphragm, and digital circuits. This is noise generated from Disturbance noise particularly affects wiring such as signal lines and output lines. In the CMOS sensor, signal charges are converted into signal voltages in the vicinity of the photodiode, so that the wiring is longer than that of the CCD and is easily affected by disturbance noise.

  In recent years, due to the miniaturization of electronic cameras, the distance between the noise source and the image sensor has become closer, and disturbance noise is more likely to occur. Further, as the sensitivity of the image sensor increases, the noise component of the image sensor is amplified, and the disturbance noise becomes conspicuous.

  As means for preventing image quality deterioration due to such disturbance noise, for example, the one described in Patent Document 1 has been proposed. In this proposal, a sample hold circuit for an optical signal and a noise signal is provided for each pixel, and the optical signal and the noise signal are stored in each pixel, and the stored signals are sequentially output from each pixel simultaneously (each column Noise correction is performed.

JP 2002-344809 A

  However, in the configuration of Patent Document 1, each pixel is compared with a normal pixel (the sample switch × 2, the selection MOS × 2, the amplification MOS × 2, and the optical signal component constituting the sample hold circuit) There are many hold capacitors × 1 and noise signal hold capacitors × 1). Accordingly, the size of one pixel is larger than that of a normal pixel. In addition, since two output lines are required for each readout column in the vertical direction, the area required for the wiring is increased. For this reason, it is difficult to apply Patent Document 1 to an image sensor with a small pixel size.

  The present invention has been made in view of the above problems, and an object thereof is to provide an imaging device having a configuration capable of suppressing disturbance noise without increasing the size of one pixel and a driving method thereof. .

In order to achieve the above object, an imaging apparatus according to the present invention includes a plurality of pixels each including a photoelectric conversion element and two-dimensionally arranged, and pixels in the same column provided for each column of the plurality of pixels. A plurality of connected signal output lines, and a first holding unit that is provided for each of the plurality of signal output lines and holds an optical signal output from the plurality of pixels via the plurality of signal output lines. A second holding unit that is provided for each of the plurality of signal output lines and holds a noise signal output from the plurality of pixels through the plurality of signal output lines, and the first holding unit. Difference means for performing a difference process between the optical signal held in the second holding means and the noise signal held in the second holding means; the optical signal held in the first holding means; and held in the second holding means An output means for outputting the noise signal thus generated to the difference means An imaging element having bets, for each row of said plurality of pixels, and holds the said predetermined row from the pixels of a given column at a first timing by reading the optical signal a first holding means, said from the pixel of the predetermined row and different columns in the same row at the first timing to read out the noise signal held in the second holding means of the different columns, the difference means the first of said predetermined column Control is performed so as to perform difference processing between the optical signal held in one holding means and the noise signal held in the second holding means in the different column, and at a second timing different from the first timing. The optical signal is read out from the pixel in the different column and held in the first holding unit in the different column, and the noise signal is read out from the pixel in the column other than the different column in the same row at the second timing. Different columns Held in the second holding means outside of the column, is held in the second holding means of said differentiating means is the different column of the first row other than the held optical signal and the different columns in the holding means Control means for performing control so as to perform difference processing with respect to the noise signal.

Further, each of which includes a photoelectric conversion element, a plurality of pixels arranged two-dimensionally, wherein the plurality of pixels a plurality of signal output lines of pixels of each same column are provided for each column is connected to the plurality of First holding means provided for each of the signal output lines and holding an optical signal output from the plurality of pixels via the plurality of signal output lines, and for each of the plurality of signal output lines A second holding unit configured to hold a noise signal output from the plurality of pixels via the plurality of signal output lines; an optical signal held in the first holding unit; and the second holding unit. Difference means for performing a difference process with the noise signal held in the output means, and output means for outputting the optical signal held in the first holding means and the noise signal held in the second holding means to the difference means this imaging apparatus having an imaging device having a preparative Akira driving method, for each row of said plurality of pixels, and holds the first holding means in the first predetermined timing sequence predetermined sequence reads an optical signal from a pixel of said first from the predetermined different columns of pixel columns in the same row at the timing to read out the noise signal held in the second holding means of the different columns, the difference means the first of said predetermined column of A step of performing control so as to perform difference processing between the optical signal held in the holding unit and the noise signal held in the second holding unit in the different column, and at a second timing different from the first timing. The optical signal is read out from the pixel in the different column and held in the first holding unit in the different column, and the noise signal is read out from the pixel in the column other than the different column in the same row at the second timing. Different Held in the second holding means columns except, held in the difference means and the second holding means of the different column of the first holding means columns except the different columns and the holding optical signal into the And a step of performing control so as to perform differential processing with the noise signal.

  According to the present invention, it is possible to provide an imaging device having a configuration capable of suppressing disturbance noise without increasing the size of one pixel and a driving method thereof.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus according to an embodiment.

  In FIG. 1, 1 is a lens for forming an optical image of a subject on a solid-state imaging device 3, 2 is a diaphragm for changing the amount of light passing through the lens 1, and 3 is a subject imaged by the lens 1 as an image signal. It is a solid-state image sensor for capturing. Reference numeral 4 denotes an image pickup signal processing circuit including a variable gain amplifier for amplifying an image signal output from the solid-state image pickup device 3 and a gain correction circuit for correcting the gain value, and 5 denotes an image output from the solid-state image pickup device 4. It is an A / D converter that performs analog-digital conversion of signals. A signal processing unit 6 performs various corrections on the image data output from the A / D converter 5 and compresses the data. 7 represents a solid-state image sensor 3, an image signal processing circuit 4, and an A / D converter 5. The timing generator outputs various timing signals to the signal processor 6.

  8 is an overall control / arithmetic unit for controlling various calculations and the entire imaging apparatus, 9 is a memory unit for temporarily storing image data, and 10 is an external interface (I / F) unit for communicating with an external computer or the like. It is. Reference numeral 11 denotes a removable recording medium comprising a semiconductor memory or the like for recording image data, and reference numeral 12 denotes a recording medium control interface (I / F) unit for recording and reading with respect to the recording medium 11. 13 is a flash unit that performs AF auxiliary light projection and flash light control, 14 is a power source unit that supplies necessary voltages to each unit including the recording medium 11 for a necessary period, and 15 is a motor for driving the lens 1. Reference numeral 16 denotes a motor for driving the diaphragm 2.

<First Embodiment>
FIG. 2 is an equivalent circuit diagram of the first embodiment of the solid-state imaging device 3 of the present invention. Each circuit element constituting the solid-state imaging element 3 is formed on a single semiconductor substrate such as single crystal silicon, although it is not particularly limited by the manufacturing technology of the semiconductor integrated circuit. In FIG. 2, only a pixel array of 3 rows and 3 columns is shown, but it goes without saying that the number of rows and columns of the pixel array is arbitrary.

  In FIG. 2, photodiodes (PD) 11 to 33 that generate optical signals are grounded on the anode side in this example. The cathode side of the PD is connected to the gates of the amplification MOSs 311 to 333 via transfer MOSs 111 to 133 for transferring optical signal charges accumulated in the PD. The gates of the amplification MOSs 311 to 333 are connected to the sources of reset MOSs 211 to 233 for resetting them, and the drains of the reset MOSs 211 to 233 are connected to a reset power source. The drains of the amplification MOSs 311 to 333 are directly connected to the power source.

  Of the transfer MOSs 111 to 133, the gates of the transfer MOSs 111 and 113 in the odd-numbered first row are connected to a first row selection line PTX11 arranged extending in the horizontal direction. The gates of the transfer MOSs 112 in the first and even columns are commonly connected to the second row selection line PTX21.

  In addition, the gate of the reset MOS 211 in the first row is connected to a row reset line PRES1 that extends in the horizontal direction. The gates of the reset MOSs 212 and 213 of the other pixel cells arranged in the first row are also connected in common to the row reset line PRES1.

  The gate of the selection MOS 411 in the first row is connected to a vertical scanning line PSEL1 arranged extending in the horizontal direction. The gates of the selection MOSs 412 and 413 of other pixel cells arranged in the first row are also commonly connected to the vertical scanning line PSEL1.

First, second row selection line as described above, the row reset line, the vertical scanning line is connected to the vertical scanning circuit 1 111, the signal voltage is supplied on the basis of the timing described later. The signal applied to each wiring is distinguished from the wiring by adding “φ” before each wiring.

For the remaining rows shown in FIG. 2, pixel cells having the same configuration, first and second row selection lines, row reset lines, and vertical scanning lines are provided. These first, second row selection lines, the row reset line, the vertical scanning lines, FaiPTX12～faiPTX13 formed by the vertical scanning circuit block 1 111, φPTX22~φPTX23, φPRES2~φPRES3, is supplied φPSEL2~φPSEL3 The

  The source of the amplification MOS 311 is connected via the selection MOS 411 to a vertical signal line V1 arranged extending in the vertical direction. The sources of the amplification MOSs 321 and 331 of the pixel cells arranged in the same column are also connected to the vertical signal line V1 via the selection MOSs 421 and 431. Similarly, the amplification MOS and the selection MOS are connected to the remaining vertical signal lines V2 to V3 shown in FIG.

  The vertical signal line V1 is connected to a constant current source 51 which is a load means, and is connected to an inverting terminal of the operational amplifier 101 via a clamp capacitor 61. The non-inverting terminal of the operational amplifier 101 is connected to the clamp voltage VC0R (VREF). The output terminal of the operational amplifier 101 is connected to the capacitor CTN1 for temporarily holding the noise signal via the noise signal transfer switch 511 and to the capacitor CTS1 for temporarily holding the optical signal via the optical signal transfer switch 521. Has been. The opposite terminals of the noise signal holding capacitor CTN1 and the optical signal holding capacitor CTS1 are grounded. A connection point between the noise signal transfer switch 511 and the noise signal holding capacitor CTN1 and a connection point between the optical signal transfer switch 521 and the optical signal holding capacitor CTS1 are respectively connected to the optical signal and the noise signal via the horizontal transfer switches 531 and 541. It is connected to a differential circuit block 131 for taking the difference. In the remaining columns V2 to V3 shown in FIG. 2, readout circuits having the same configuration are provided.

  The gates of the noise signal transfer switches 511 and 513 arranged in the odd-numbered columns and the optical signal transfer switches 522 arranged in the even-numbered columns are commonly connected to the first transfer signal input line PT11. The gates of the noise signal transfer switch 512 arranged in the even-numbered column and the optical signal transfer switches 521 and 523 arranged in the odd-numbered column are connected in common to the second transfer signal input line PT21. Signal voltages φPT11 and φPT21 are supplied to PT11 and PT21, respectively, based on timing described later.

A horizontal transfer switch 541 which is arranged to the vertical signal line V1, the gate of the horizontal transfer switch 532 which is arranged to the vertical signal lines V2 are connected in common to a column selection line H1, are connected to the horizontal scanning circuit 1 121. The gates of the optical signal horizontal transfer switch 542 arranged on the vertical signal line V2 and the noise signal horizontal transfer switch 533 arranged on the vertical signal line V3 are connected in common to the column selection line H3 and connected to the horizontal scanning circuit block 121. Is done.

  Next, the operation of the solid-state imaging device 3 having the configuration shown in FIG. 2 in the first embodiment will be described with reference to FIG. Note that “n” in FIG. 3 indicates the number of rows (1 to 3), and is sequentially driven for each row as described below. Here, the operation of the first row will be described representatively.

  After the row selection pulse φPSEL1 becomes high level at time t1, the pixel reset pulse φPRES1 becomes high level at time t2, and the gates of the amplification MOSs 311 to 313 are reset to the reset potential.

  After the pixel reset pulse φPRES1 becomes low level at time t3, the clamp pulse φPC0R becomes high level at time t4, and the reset potential is read to the vertical signal lines V1 to V3 and clamped to the capacitors 61 to 63.

  After the clamp pulse PC0R becomes low level at time t5, the transfer pulse φPTX11 at time t6 becomes high level, and the optical signals of PD11 and PD13 are transferred to the gates of the amplification MOSs 311 and 313, and at the same time the optical signal is a vertical signal line. Read to V1 and V3. Further, a noise signal (including disturbance noise) generated when the optical signal is read out to the vertical signal lines V1 and V3 is read out to the vertical signal line V2.

  At time t7, the transfer pulse φPT11 becomes high level, the optical signals of PD11 and PD13 read to the vertical signal lines V1 and V3 are transferred to CTS1 and CTS3, and the noise signal of the vertical signal line V2 is transferred to CTN2.

  At time t8, the transfer pulse φPT11 becomes low level, and at time t9, the transfer pulse φPTX11 becomes low level.

  Through the operations so far, the optical signals of the odd-numbered pixel cells connected to the first row are held in the optical signal holding capacitors CTS1 and CTS3, and the noise signals of the even-numbered pixel cells are supplied to the signal holding capacitor CTN2. Retained.

  Next, the pixel reset pulse φPRES1 becomes high level at time t10, the gates of the amplification MOSs 311 to 313 are reset to the reset power source again, and the pixel reset pulse φPRES becomes low level at time t11.

  At time t12, the clamp pulse φPC0R becomes high level, the reset potential at time t12 is read out to the vertical signal lines V1 to V3, multiplied by the gain and clamped to the capacitors 61 to 63, and then at time t13, the clamp pulse φPC0R Becomes low level.

  At time t14, the transfer pulse φPTX21 becomes high level, and the optical signal of the PD 12 is transferred to the gate of the amplification MOS 312 and at the same time, the optical signal is read out to the vertical signal line V2. In addition, noise signals (including disturbance noise) generated when the optical signal is read out to the vertical signal line V2 are read out to the vertical signal lines V1 and V3.

  At time t15, the transfer pulse φPT21 becomes high level, and the optical signal of the PD 12 read to the vertical signal line V2 is transferred to the CTS2. Further, the noise signals of the vertical signal lines V1 and V3 are transferred to CTN1 and CTN3.

  At time t16, the transfer pulse φPT21 becomes low level, and at time t17, the transfer pulse φPTX21 becomes low level.

  With the operations so far, the optical signals of the even-numbered pixel cells connected to the first row are held in the optical signal holding capacitor CTS2, and the noise signals of the odd-numbered pixel cells are sent to the signal holding capacitors CTN1 and CTN3. Retained.

  At time t18, the row selection pulse φPSEL1 becomes low level. Thereafter, between time t19 and t20, the signals φH1 to φH3 from the horizontal scanning circuit 7 cause the gates of the horizontal transfer switches 531 to 533 and 541 to 543 in each column to be sequentially high level. As a result, the voltages held in the optical signal holding capacitors CTS1 to CTS3 and the noise signal holding capacitors CTN1 to CTN3 are sequentially read out to the differential circuit 131 and output to the output terminal. Specifically, as can be seen from the wiring in FIG. 2, for example, when φH1 becomes high level, the voltage is read from the optical signal holding capacitor CTS1 in the first column and the noise signal holding capacitor CTN2 in the second column, Difference is made by the dynamic circuit 131. As described above, since the noise signal is subtracted from the optical signal read out at the same timing, it is possible to reduce the amount of disturbance noise generated at the time of reading out the optical signal from the optical signal.

  When reading is completed at time t20, the above-described operation is repeated for the second row, and when reading of the second row is completed, the above-described operation is repeated for the third row.

  In the first embodiment, after the odd-numbered noise signals and the even-numbered optical signals are read out first, the even-numbered noise signals and the odd-numbered optical signals are read out. However, the present invention is not limited to this, and the noise signal of the odd column and the optical signal of the even column may be read after the noise signal of the even column and the optical signal of the odd column are read first.

  As described above, according to the first embodiment, disturbance noise generated in the vertical signal line can be reduced from the optical signal without increasing the number of components of each pixel.

<Second Embodiment>
FIG. 4 is an equivalent circuit diagram of the solid-state imaging device according to the second embodiment of the present invention.

In the solid-state imaging device shown in FIG. 4, the horizontal transfer switch 5531 arranged on the vertical signal line V1 and the gate of the horizontal transfer switch 42 arranged on the vertical signal line V2 are connected in common to the column selection line H1, and horizontal scanning is performed. Connected to circuit 1 121. Further, the optical signal horizontal transfer switch 532 arranged on the vertical signal line V2 and the gate of the noise signal horizontal transfer switch 541 arranged on the vertical signal line V1 are connected in common to the column selection line H3, and the horizontal scanning circuit 1 121 is connected. Connected to. Further, the horizontal transfer switch 33 disposed to the vertical signal line V3, the gate of the horizontal transfer switch 544 which is arranged to the vertical signal lines V4 are connected in common to the column select line H3, is connected to the horizontal scanning circuit 1 121 . Further, the gates of the optical signal horizontal transfer switch 534 arranged on the vertical signal line V4 and the noise signal horizontal transfer switch 543 arranged on the vertical signal line V3 are connected in common to the column selection line H4, and the horizontal scanning circuit 1 121 is connected. Connected to.

  Since other configurations and driving methods are the same as those in the first embodiment, the description thereof is omitted here. By configuring the solid-state imaging device as shown in FIG. 4, in the second embodiment, the noise signals are subtracted from the optical signal by two columns.

  Therefore, according to the second embodiment, the same effect as that of the first embodiment can be obtained.

<Third Embodiment>
FIG. 5 is an equivalent circuit diagram of a solid-state imaging device according to the third embodiment of the present invention.

  In the solid-state imaging device shown in FIG. 5, signals are read out using two channels whose vertical signal line reading directions are different every other column. The gates of the horizontal transfer switches 531, 533, 535, 541, 543, and 545 of the vertical signal lines V1, V3, and V5 are connected to the column selection lines H1, H3, and H5, and connected to the first horizontal scanning circuit 121-1. The On the other hand, the gates of the horizontal transfer switches 532, 534, 536, 542, 544, 546 of the vertical signal lines V2, V4, V6 are connected to the column selection lines H2, H4, H6, and the second horizontal scanning circuit block 121-2. Connected to.

  In the vertical signal lines V1, V3, and V5, the connection points between the noise signal transfer switches 511, 513, and 515 and the noise signal holding capacitors CTN1, CTN3, and CTN5 are connected to the first difference via the transfer switches 531, 533, and 535, respectively. Connected to the dynamic circuit 131-1. The connection points of the optical signal transfer switches 521, 523, and 525 and the optical signal holding capacitors CTS1, CTS3, and CTS5 are connected to the first differential circuit 131-1 via the transfer switches 541, 543, and 545, respectively. Is done. As a result, the first differential circuit 131-1 takes the difference between the odd-numbered optical signal and the noise signal. Since other configurations are the same as those of the first embodiment or the second embodiment, description thereof is omitted here.

Further, the reading circuit similar arrangement is provided for the remaining vertical signal lines V2, V4, V6, shown in Figure 5. Also in the third embodiment, the driving method is the same as in the first embodiment or the second embodiment. However, in the third embodiment, the read channel is different every other column. Therefore, an optical signal on the vertical signal line V1 and a noise signal on the vertical signal line V3, an optical signal on the vertical signal line V3, and a noise signal on the vertical signal line V5 are adjacent to each other in the same channel as the optical signal in one column. Are simultaneously read out.

  According to the above configuration, in addition to the same effects as those of the first embodiment, the readout channel is made up of two systems, so that charges can be read out from the solid-state imaging device at a higher speed.

  In the third embodiment, the case of two-channel reading in which the reading direction of the vertical signal line is different every other row has been described, but the present invention is not limited to this. For example, there are various methods for dividing channels, such as changing the reading direction every two rows or dividing the channel near the center in the horizontal direction. In any case, the present invention is configured so that an optical signal and a noise signal can be read out at the same timing for two adjacent columns in each channel.

  In the first to third embodiments, the case where the differential circuit block 131 is formed on the same semiconductor substrate as the solid-state imaging device has been described. However, the optical signal and noise signal of each pixel are obtained. It is also possible to separately output from the image sensor and take the difference with an external differential circuit.

It is a block diagram which shows the structure of the imaging device in embodiment of this invention. 1 is an equivalent circuit diagram illustrating a schematic configuration of a solid-state imaging element according to a first embodiment of the present invention. It is a timing diagram for demonstrating operation | movement of the solid-state image sensor in the 1st Embodiment of this invention. It is an equivalent circuit diagram which shows schematic structure of the solid-state image sensor in the 2nd Embodiment of this invention. It is an equivalent circuit diagram which shows schematic structure of the solid-state image sensor in the 3rd Embodiment of this invention.

Claims (6)

A plurality of pixels, each including a photoelectric conversion element, arranged two-dimensionally, a plurality of signal output lines provided for each column of the plurality of pixels and connected to pixels in the same column, and the plurality of signal outputs A first holding unit provided for each of the lines and holding an optical signal output from the plurality of pixels via the plurality of signal output lines; and provided for each of the plurality of signal output lines. Second holding means for holding noise signals output from the plurality of pixels via the plurality of signal output lines, optical signals held by the first holding means, and holding by the second holding means Differential means for performing differential processing on the noise signal, and output means for outputting the optical signal held in the first holding means and the noise signal held in the second holding means to the difference means. An image sensor provided;
For each row of the plurality of pixels, an optical signal is read from a pixel in a predetermined column at a first timing and is held in the first holding unit in the predetermined column, and the same row is read at the first timing. An optical signal read out from a pixel in a column different from the predetermined column and held in the second holding unit in the different column, and the difference unit is held in the first holding unit in the predetermined column And control to perform a difference process between the noise signal held in the second holding unit in the different column and read out the optical signal from the pixel in the different column at a second timing different from the first timing. Holding the first column in the different column and reading out a noise signal from a pixel in a column other than the different column in the same row at the second timing to read the noise signal in the column other than the different column. Retention The difference means performs difference processing between the optical signal held in the first holding means in the different column and the noise signal held in the second holding means in a column other than the different column. Control means for controlling
An imaging device comprising:   The output means sets two adjacent rows as one set and outputs the optical signal held by the first holding means and the noise signal held by the second holding means at the same timing. The imaging apparatus according to claim 1.   The imaging apparatus according to claim 1, wherein the output unit includes a plurality of output channels. A clamp circuit is connected to each signal output line,
4. The control unit according to claim 1, wherein the control unit clamps a reset potential of the pixel in the clamp circuit, and controls to read out the optical signal and the noise signal through the clamp circuit. 5. The imaging apparatus of Claim 1.   The imaging apparatus according to claim 1, further comprising: a lens that focuses light on the plurality of pixels; and a signal processing unit that processes a signal output from the difference unit. A plurality of pixels each including a photoelectric conversion element, a plurality of signal output lines provided for each column of the plurality of pixels and connected to pixels in the same column, and the plurality of signal outputs A first holding unit provided for each of the lines and holding an optical signal output from the plurality of pixels via the plurality of signal output lines; and provided for each of the plurality of signal output lines. Second holding means for holding noise signals output from the plurality of pixels via the plurality of signal output lines, optical signals held by the first holding means, and holding by the second holding means Differential means for performing differential processing on the noise signal, and output means for outputting the optical signal held in the first holding means and the noise signal held in the second holding means to the difference means. Driving method of imaging apparatus having imaging element provided There,
For each row of the plurality of pixels, an optical signal is read from a pixel in a predetermined column at a first timing and is held in the first holding unit in the predetermined column, and the same row is read at the first timing. An optical signal read out from a pixel in a column different from the predetermined column and held in the second holding unit in the different column, and the difference unit is held in the first holding unit in the predetermined column And controlling to perform a difference process between the noise signal held in the second holding means in the different column,
Optical signals are read from the pixels in the different columns at a second timing different from the first timing and are held in the first holding means in the different columns, and the different columns in the same row at the second timing A noise signal is read out from pixels in a column other than that and held in the second holding unit in a column other than the different column, and the difference unit and the optical signal held in the first holding unit in the different column Controlling to perform a difference process with the noise signal held in the second holding means in a column other than a different column;
A method for driving an imaging apparatus, comprising:

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