JP2020136860A - Image pickup device, reading method thereof, and imaging apparatus - Google Patents

Abstract

To provide an image pickup device which has a plurality of pixels divided into a plurality of blocks, and can read out a signal from a light-shielded pixel even in a block which does not have the light-shielded pixel.SOLUTION: An image pickup device 100 includes: a first substrate 200 on which a plurality of pixels are arrayed; a plurality of output lines 406 and 407 that are provided in each of a plurality of blocks which divide the plurality of pixels into at least light-shielded pixels 303 and a part of aperture pixels 302, and are connected to a plurality of pixels contained in the blocks; a readout circuit 305 that is provided so as to correspond to an aperture block 304 which does not contain the light-shielded pixel 303; and a first switch 408 that connects the light-shielded output line 407 of a light-shielded block 306 which contains the light-shielded pixel 303, with the aperture output line 406 of the aperture block. The readout circuit 305 reads out a signal from the light-shielded pixel 303 that is contained in the light-shielded block 306, through the light-shielded output line 407, the first switch 408, and the aperture output line 406.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image sensor.

The image pickup device has a first substrate on which a plurality of aperture pixels for photoelectric conversion are arranged. Then, the reading circuit AD-converts the signal read from the aperture pixel, for example. This AD conversion value has a value corresponding to the amount of light photoelectrically converted by the aperture pixel, and can be used as a pixel value indicating the amount of light received by the aperture pixel.

JP-A-2009-177207 Japanese Unexamined Patent Publication No. 2014-155175

By the way, some image pickup devices divide a plurality of pixels into a plurality of blocks for each area of the first substrate, and read a signal from the aperture pixel for each block by a read circuit provided corresponding to each block. (Patent Documents 1 and 2). However, when a plurality of pixels are divided into a plurality of blocks, there is a possibility that the plurality of blocks may have blocks that do not have light-shielding pixels that do not receive light. The read circuit corresponding to the block having no light-shielding pixel cannot read the signal from the light-shielding pixel. As a result, in an image sensor in which a plurality of pixels are divided into a plurality of blocks, the signal processing circuit connected to the reading circuit may not be able to correct the signal read from the aperture pixel by the signal based on the light-shielding pixel. There is.

In this way, in an image sensor that divides a plurality of pixels into a plurality of blocks, or in an image pickup device that uses the image sensor, it is required that a signal can be read from the light-shielding pixels even in a block that does not have the light-shielding pixels. Has been done.

The imaging device according to the present invention has a first substrate in which a plurality of pixels including a light-shielding pixel and an aperture pixel for photoelectric conversion are arranged, and a plurality of the plurality of pixels that separate at least a light-shielding pixel and a part of the aperture pixel. It is provided for each block and is provided corresponding to a plurality of output lines connected to a plurality of pixels included in the block and an opening block which is the block not including the light-shielding pixel, and is included in the opening block. A read circuit that reads signals from a plurality of pixels through the output lines, a light-shielding output line that is the output line of the light-shielding block that is the block including the light-shielding pixels, and an aperture output line that is the output line of the opening block. The read circuit, which has a first switch to be connected and corresponds to the opening block, reads a signal from a light-shielding pixel included in the light-shielding block through the light-shielding output line, the first switch, and the opening output line. ..

In the present invention, in an image sensor that divides a plurality of pixels into a plurality of blocks, a signal can be read from the light-shielding pixels even in a block that does not have the light-shielding pixels.

It is a block diagram which shows the structure of the image pickup apparatus which has the image pickup element which concerns on 1st Embodiment of this invention. It is a figure schematically explaining the laminated structure of a plurality of chip-shaped substrates about the image pickup device of FIG. It is a figure which shows typically the functional layout in the pixel substrate and the reading substrate of FIG. It is explanatory drawing of the circuit mounted on the image sensor of FIG. It is explanatory drawing of the clamp processing by the signal processing circuit of FIG. It is a timing chart of the process of reading a signal of an aperture pixel. 6 is a timing chart of a process of reading signals as pixel data of a plurality of pixels when the image sensor of FIG. 3 outputs one frame of image data. It is a functional layout diagram of the image pickup device which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the circuit mounted on the image sensor of FIG. It is a timing chart of the process of reading a signal from a plurality of pixels in the whole image sensor of FIG. It is a functional layout diagram of the image pickup device which concerns on 3rd Embodiment of this invention. It is explanatory drawing of the circuit mounted on the image sensor of FIG. It is a timing chart of the process of reading a signal from a plurality of pixels in the whole image sensor of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the configurations described in the following embodiments are merely examples, and the scope of the present invention is not limited by the configurations described in the embodiments.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an image pickup device 1 having an image pickup device 100 according to the first embodiment of the present invention. The image pickup device 1 of FIG. 1 includes an image pickup element 100, an image pickup lens 101, a lens drive unit 102, a memory unit 104, a display unit 105, a recording unit 106, an operation unit 107, and an overall control calculation unit 103 to which these are connected. Have. The imaging lens 101 has, for example, a focus lens and an aperture (not shown). The image pickup lens 101 collects the light of the subject on the image pickup element 100. The lens drive unit 102 performs focus drive and aperture drive on the image pickup lens 101. The image sensor 100 captures an optical image imaged by the image pickup lens 101. The image sensor 100 outputs a signal for the captured image. The memory unit 104 stores the image data captured by the image sensor 100. The display unit 105 is, for example, a liquid crystal display device. The display unit 105 displays various setting screens for imaging and captured images. The operation unit 107 includes, for example, a release button, a setting button, and a touch panel device. The operation unit 107 is operated by the user for imaging. The recording unit 106 is, for example, a semiconductor memory device or a hard disk device that is detachably attached to the image pickup apparatus 1. The recording unit 106 records a program for controlling the operation of the image pickup apparatus 1, setting data, captured image data, and the like. The overall control calculation unit 103 is, for example, a CPU. The CPU reads the program from the recording unit 106 and executes it. As a result, the overall control calculation unit 103 functions as a control unit that controls the overall operation of the image pickup apparatus 1. For example, when the release button is operated, the overall control calculation unit 103 instructs the image sensor 100 to take an image and controls the image sensor 100. The overall control calculation unit 103 acquires a signal of the captured image from the image sensor 100, generates image data, and records it in the recording unit 106. Further, the overall control calculation unit 103 outputs the image data during or after imaging to the display unit 105, and causes the display unit 105 to display the image.

FIG. 2 is a diagram schematically illustrating a laminated structure of a plurality of chip-shaped substrates for the image pickup device 100 of FIG. 1. The image pickup device 100 of FIG. 2 has a pixel substrate 200 as a first substrate and a read substrate 201 as a second substrate. The pixel substrate 200 and the read substrate 201 are, for example, semiconductor substrates. A pixel region 202, a vertical control circuit 203, and a horizontal control circuit 204 are formed on the pixel substrate 200 as functional blocks. A read area 205, a timing generator (TG) 206, a signal processing circuit 207, and a digital signal output circuit 208 are formed on the read board 201 as functional blocks. The reading substrate 201 is arranged so as to be overlapped on the back side of the pixel region 202 that receives light of the pixel substrate 200. The above-mentioned parts of the reading board 201 and the above-mentioned parts of the pixel board 200 are electrically connected by using electrodes or connectors (not shown).

FIG. 3 is a diagram schematically showing the functional layout of the pixel substrate 200 and the readout substrate 201 of FIG. In the pixel area 202, a plurality of pixels are arranged by dividing into a light-shielding area 300 and an opening area 301. The plurality of pixels are arranged in a matrix along the vertical direction and the horizontal direction. A plurality of pixels including a light-shielding pixel 303 and an aperture pixel 302 for photoelectric conversion are arranged on the light receiving surface of the pixel substrate 200. A plurality of pixels capable of optically receiving a subject image are formed in the opening region 301. Hereinafter, a pixel that is not optically shaded and can receive the light of the subject is referred to as an aperture pixel 302. A plurality of pixels that are optically shaded are formed in the light-shielding region 300. In FIG. 3, the light-shielding region 300 is arranged above the opening region 301. Hereinafter, the pixel that is optically shaded in this way is referred to as a light-shielding pixel 303. In FIG. 3, the plurality of light-shielding pixels 303 (0) to 303 (23) are provided in a row in the uppermost row of the figure for the plurality of pixels arranged in a matrix. Then, a plurality of opening blocks 304 are arranged in the opening region 301. The aperture block 304 includes a part of the plurality of aperture pixels 302 arranged in the aperture region 301, and does not include the light-shielding pixel 303. For example, in FIG. 3, a total of 24 opening blocks 304 are set in the opening area 301 by an array of 4 rows × 6 columns. The aperture block 304 includes a total of 16 aperture pixels 302 in an array of 4 rows × 4 columns. In the light-shielding region 300, a plurality of light-shielding blocks 306 are arranged so as to correspond to the opening block 304. The light-shielding block 306 includes a plurality of light-shielding pixels 303 having the same number of rows as the opening block 304.

In the read area 205, a plurality of read circuits 305 are formed at positions overlapping each opening block 304. In FIG. 3, a total of 24 read circuits 305 are formed in the read area 205 by an arrangement of 4 rows × 6 columns. In the following, when a plurality of read circuits 305 are distinguished from each other, coordinates (0, 0) to (5, 3) are added to each read circuit 305 from the upper left to the lower right of the figure. The read circuit 305 is connected to the corresponding aperture block 304. In FIG. 3, the opening block 304 and the reading circuit 305 are arranged in a matrix of 6 rows × 4 columns. In this case, for example, the leftmost opening block 304 (0,0) is connected to the leftmost read circuit 305 (0,0). By connecting the opening blocks 304 and the reading circuit 305 that are vertically stacked in FIG. 2 in this way, the wiring that connects them can be shortened. The wiring resistance of the connecting wiring can be minimized. In FIG. 3, the light-shielding pixel 303 is in one row, and the aperture block 304 is composed of a total of 16 aperture pixels 302 in 4 rows × 4 columns, but the number of pixels may be different from this. The number of opening blocks 304 and the number of reading circuits 305 are 6 × 4 = 24, respectively, but the number of opening blocks 304 may be different from this. For example, the actual image sensor 100 includes dozens of rows of light-shielding pixels 303 and tens of millions of aperture pixels 302. The opening blocks 304 and the reading circuits 305 may be provided in an appropriate number depending on the area of the semiconductor substrate.

The timing generator 206 is connected to each part such as a vertical control circuit 203, a horizontal control circuit 204, a signal processing circuit 207, and a digital signal output circuit 208 provided in the image sensor 100. The timing generator 206 controls the operation timings of the vertical control circuit 203, the horizontal control circuit 204, the read circuit 305, the signal processing circuit 207, and the digital signal output circuit 208 under the control of the overall control calculation unit 103 of the image pickup apparatus 1. To do. The vertical control circuit 203 and the horizontal control circuit 204 output drive signals to a plurality of pixels formed in the pixel area 202 at the operation timing controlled by the timing generator 206, and control the signal reading from each pixel. Read control includes processes such as pixel charge reset, charge accumulation by photoelectric conversion in pixels, charge transfer to the read circuit 305, and signal output from the read circuit 305. The read circuit 305 reads a signal from, for example, the aperture pixel 302, performs AD conversion, and outputs a digital value as pixel data of the aperture pixel 302. The signal processing circuit 207 is connected to a plurality of read circuits 305. The signal processing circuit 207 corrects the pixel data which is the AD conversion value of each aperture pixel 302 output from the reading circuit 305. The signal processing circuit 207 uses, for example, the pixel data which is the AD conversion value of the light-shielding pixel 303 as the correction value of the clamping process to the reference signal level, and subtracts and corrects the pixel data of the opening pixel 302. As a result, as a pixel value indicating the amount of light received by the aperture pixel 302, it is possible to obtain a value satisfactorily corresponding to the amount of light photoelectrically converted by the aperture pixel 302. The digital signal output circuit 208 outputs the pixel data of the aperture pixels 302 processed by the signal processing circuit 207 to the overall control calculation unit 103.

By the way, when the plurality of pixels of the image sensor 100 are divided into a plurality of aperture blocks 304 for each area of the pixel substrate 200, the plurality of aperture blocks 304 do not have the light-shielding pixels 303 that do not receive light. become. The image sensor 100 usually includes a light-shielding pixel 303 that is shielded from light so as not to react to light in order to obtain a signal (black reference signal) that serves as a signal level reference signal, and the signal of the aperture pixel 302 is a light-shielding pixel 303. The correction calculation is performed based on the signal level of. As a result, the pixel data of the aperture pixel 302 can be clamped to a predetermined level. It is possible to correct the dark current due to long-time exposure included in the pixel data of the aperture pixel 302. However, the read circuit 305 corresponding to the aperture block 304 that does not have the light-shielding pixel 303 cannot read the signal from the light-shielding pixel 303. As a result, in the image sensor 100 in which the plurality of pixels are divided into the plurality of aperture blocks 304, the signal processing circuit 207 connected to the read circuit 305 corrects the signal read from the aperture pixels 302 by the signal based on the light-shielding pixels 303. You may not be able to. As described above, in the image sensor 100 that divides a plurality of pixels into a plurality of aperture blocks 304, it is required that the signal can be read from the light-shielding pixel 303 even in the aperture block 304 that does not have the light-shielding pixel 303. ing.

FIG. 4 is an explanatory diagram of a circuit mounted on the image sensor 100 of FIG. In FIG. 4, among the circuits of the image sensor 100 of FIG. 3, the aperture pixels 302, the light-shielding pixels 303, the read circuit 305, and the signal processing circuit 207 for a plurality of aperture blocks 304 arranged in the column direction as an example are shown. It is shown. The plurality of aperture pixels 302 are shown separately for each aperture block 304 on the pixel substrate 200. The plurality of light-shielding pixels 303 are shown in the light-shielding region 300 on the pixel substrate 200. The plurality of read circuits 305 are shown in the read board 201 corresponding to the opening block 304. The broken line in the center of the figure indicates the boundary between the circuit of the pixel substrate 200 and the circuit of the readout substrate 201.

The aperture pixel 302 includes a photodiode (PD) 400, a transfer transistor 401, a floating diffusion (FD) 402, an amplification transistor 404, a selection transistor 405, an aperture output line 406, and a reset transistor 403. The photodiode 400 is a photoelectric conversion element. The photodiode 400 receives the light focused by the image pickup lens 101 on the pixel substrate 200, and generates an electric charge according to the amount of the received light. The transfer transistor 401 is connected between the photodiode 400 and the floating diffusion 402. When the transfer transistor 401 is in the ON state, it connects the photodiode 400 and the floating diffusion 402. When the transfer transistor 401 is switched from the on state to the off state, the floating diffusion 402 holds a voltage corresponding to the electric charge generated by the photodiode 400 during the on period. The reset transistor 403 is connected between the power supply and the floating diffusion 402. When the reset transistor 403 is turned on, the potential of the floating diffusion 402 is reset to the power supply potential. When the transfer transistor 401 is controlled to be on together with the reset transistor 403, the stored charge is discharged from the photodiode 400 to reset the photodiode 400. A floating diffusion 402 is connected to the source terminal of the amplification transistor 404. The amplification transistor 404 functions as a source follower amplifier. The selection transistor 405 is connected between the amplification transistor 404 and the aperture output line 406. When the selection transistor 405 is in the ON state, the voltage corresponding to the floating diffusion 402 is output to the aperture output line 406. The aperture output line 406 is commonly connected to the selection transistors 405 of the plurality of aperture pixels 302 arranged in the column direction in the aperture block 304. The aperture output line 406 is connected to the read circuit 305 corresponding to the aperture block 304. The aperture output line 406 is provided for each aperture block 304 and is connected to a plurality of pixels included in the aperture block 304. The transfer transistor 401, the reset transistor 403, and the selection transistor 405 are connected to the vertical control circuit 203 or the horizontal control circuit 204. The transfer transistor 401 is on / off controlled by the signal level of the drive signal φTX. The reset transistor 403 is on / off controlled by the signal level of the drive signal φRES. The selection transistor 405 is on / off controlled by the signal level of the drive signal φSEL. The vertical control circuit 203 outputs each drive signal as a shared signal to a plurality of aperture pixels 302 arranged in the row direction. The horizontal control circuit 204 outputs each drive signal as a shared signal to a plurality of aperture pixels 302 arranged in the column direction. The drive signals φTX, φRES, and φSEL control the reading of a signal from an arbitrary aperture pixel 302 in the pixel area 202.

The read circuit 305 includes a current source 410, an S / H (sample hold) switch 411, an S / H capacitor 412, a comparator 413, a counter 414, and a memory / CDS circuit 415. The aperture output line 406 of the aperture block 304 is connected to the comparator 413 via the S / H switch 411. The current source 410 is connected to the aperture output line 406. The current source 410 functions as a load for the amplification transistor 404. The S / H capacitor 412 is connected between the S / H switch 411 and the comparator 413. The S / H switch 411 is controlled by, for example, the drive signal φS / H. When the S / H switch 411 is in the ON state, the voltage output from the aperture pixel 302 is applied to the S / H capacitor 412. After that, when the S / H switch 411 is controlled from the on state to the off state, the S / H capacitor 412 holds the applied voltage. The comparator 413 outputs a Low level or a high level depending on the magnitude relationship between the holding voltage held in the S / H capacitor 412 and the reference voltage Vslope supplied from a reference voltage generation circuit (not shown). The comparator 413 outputs a low level voltage when the holding voltage is lower than the reference voltageized Vslope. If the holding voltage is higher than the reference voltageized Vslope, the comparator 413 outputs a high level voltage. The reference voltage generation circuit (not shown) controls the output reference voltage Vslope so that the voltage increases or decreases with a constant slope. The counter 414 becomes effective at the same time as the change of the reference voltage Vslope starts. The counter 414 counts up in response to CLK. The counter 414 stops counting when the holding voltage becomes higher than the reference voltage Vslope and a high level voltage is output from the comparator 413. The counter 414 counts the number of clocks in the period until the reference voltage Vslope at which the lamp changes becomes higher than the holding voltage. The counter 414 counts the period from the timing when the output of the comparator 413 becomes low level and the change of the reference voltage Vslope is started. As a result, a count value corresponding to the holding voltage can be obtained. The holding voltage is AD converted to a digital value. The memory / CDS circuit 415 has an internal memory (not shown). The memory / CDS circuit 415 generates a signal (hereinafter, “SN signal”) corresponding to the electric charge accumulated by the photodiode 400 by using the correction value held in the internal memory. The internal memory records, for example, a digital value obtained by AD-converting a reset level signal (hereinafter, “N signal”) of the floating diffusion 402. In this case, the memory / CDS circuit 415 subtracts the digital value of the N signal from the count value to generate the SN signal. The memory / CDS circuit 415 outputs an SN signal to the signal processing circuit 207 through the digital output line 416 at the timing controlled by the timing generator 206. The plurality of read circuits 305 sequentially output SN signals to the signal processing circuit 207 through the common digital output line 416 so that their outputs do not overlap with each other. In this way, the read circuit 305 is provided corresponding to the opening block 304 that does not include the light-shielding pixel 303. The read circuit 305 reads a signal from the plurality of aperture pixels 302 included in the aperture block 304 through the aperture output line 406.

The light-shielding pixel 303 has the same configuration as the aperture pixel 302 described above. However, the photodiode 400 of the light-shielding pixel 303 is shielded from light so as not to receive light. The vertical control circuit 203 and the horizontal control circuit 204 control the reading of signals from the plurality of light-shielding pixels 303, similarly to the plurality of aperture pixels 302. The plurality of light-shielding pixels 303 are connected to one common light-shielding output line 407 for each number corresponding to the number of rows of the plurality of aperture pixels 302 in the opening block 304, and for every four in the figure. Similar to the plurality of aperture pixels 302, the plurality of light-shielding pixels 303 are divided into a plurality of light-shielding blocks 306 for each row of the aperture blocks 304. However, the reading board 201 is not provided with the reading circuit 305 corresponding to the light-shielding block 306. Further, the light-shielding output line 407 provided in the light-shielding block 306 corresponding to the aperture output line 406 is connected to all of the plurality of light-shielding pixels 303 included in the light-shielding block 306 in a row.

Then, the light-shielding output line 407 of the light-shielding block 306 is connected to the aperture output line 406 of the opening block 304 adjacent in the row direction by the first switch 408. Further, the opening output line 406 of each opening block 304 is connected to the opening output line 406 of another opening block 304 adjacent in the row direction by the second switch 409. The light-shielding block 306, the opening block 304 connected to the light-shielding block 306 by the first switch 408, and the opening block 304 connected to the other opening block 304 by the second switch 409 are arranged in the row direction on the pixel substrate 200. It is installed side by side. The first switch 408 and the second switch 409 are collectively controlled for each row by, for example, the drive signal φSW. When the first switch 408 and the second switch 409 are in the ON state, the light-shielding output line 407 and a plurality of aperture output lines 406 arranged in the row direction are connected to each other. The same signal is input to all of the plurality of read circuits 305 arranged in the column direction. When the light-shielding pixel 303 is selected in this state, the signal from the light-shielding pixel 303 is input to all the read circuits 305 in the column direction. The read circuit 305 can read the signal of the light-shielding pixel 303, perform AD conversion, and output the pixel data of the light-shielding pixel 303. The read circuit 305 corresponding to the aperture block 304 adjacent to the light-shielding block 306 reads a signal from the light-shielding pixel 303 through the light-shielding output line 407, the first switch 408, and the aperture output line 406. The read circuit 305 corresponding to the aperture block 304 not adjacent to the shading block 306 passes through the shading output line 407, the first switch 408, the other aperture output line 406, the second switch 409, and its own aperture output line 406. Read the signal from 303. A plurality of reading circuits 305 provided side by side in the column direction can simultaneously read signals from a common light-shielding pixel 303. When connecting the aperture output lines 406 to each other, it is desirable that in the plurality of read circuits 305, only one of the current sources 410 is connected to the aperture output lines 406. In this case, in the other read circuit 305, the current source 410 may be disconnected from the aperture output line 406.

FIG. 5 is an explanatory diagram of clamping processing by the signal processing circuit 207 of FIG. The signal processing circuit 207 of FIG. 5 has a clamp value generation unit 600 and a subtraction circuit 601. The SN signal of the aperture pixel 302 and the SN signal of the light-shielding pixel 303 can be input to the signal processing circuit 207 from the read circuit 305. The clamp value generation unit 600 holds the acquired SN signal of the light-shielding pixel 303 as a clamp value as a black reference signal by the drive signal from the timing generator 206. When the clamp value generation unit 600 has acquired the SN signals of the plurality of light-shielding pixels 303, the clamp value generation unit 600 may hold the value obtained by averaging them as the clamp value as the black reference signal. The clamp value generation unit 600 may use, for example, the average value or the median value of the pixel data of the plurality of light-shielding pixels 303 obtained from the plurality of read circuits 305. As a result, the clamp value generation unit 600 may hold the clamp value with the error caused by the individual read circuit 305 reduced. When the SN signal of the opening pixel 302 is input, the subtraction circuit 601 subtracts the clamp value of the clamp value generating unit 600 from the value of the SN signal of the opening pixel 302. As a result, it is possible to remove the deviation of the black level due to the influence of dark current or the like from the pixel data of the aperture pixel 302. The pixel data of the aperture pixel 302 can be corrected to a value based on the black level of the signal. The signal processing circuit 207 outputs the pixel data of the aperture pixels 302 clamped by the subtraction circuit 601.

FIG. 6 is a timing chart of the process of reading the signal of the aperture pixel 302. FIG. 6A is a drive signal φSEL that controls the on / off state of the selection transistor 405. FIG. 6B is a drive signal φRES that controls the on / off state of the reset transistor 403. FIG. 6C is a drive signal φTX that controls the on / off state of the transfer transistor 401. FIG. 6D is a drive signal φS / H that controls the on / off state of the S / H switch 411. FIG. 6E shows a reference voltage Vslope and a holding voltage VS / H input to the comparator 413. Further, Vpix is the voltage of the aperture output line 406 output from the aperture pixel 302. These drive signals and the reference voltage Vslope are output from the vertical control circuit 203, the horizontal control circuit 204, or the signal processing circuit 207. The timing generator 206 controls the timing of these drive signals and the reference voltage Vslope. FIG. 6F is the output of the comparator 413. FIG. 6 (G) shows the operating state of the counter 414. In the figure, time goes from left to right.

In FIG. 6, the image sensor 100 first resets the aperture pixel 302. After that, the image sensor 100 reads out the electric charge accumulated in the photodiode 400 of the aperture pixel 302 after reset and AD-converts it by the reading circuit 305. At the timing t500, the timing generator 206 switches the drive signal φRES to a high level. The reset transistor 403 goes from the off state to the on state. The voltage of the floating diffusion 402 of the aperture pixel 302 is reset. At the same time, the timing generator 206 switches the drive signal φSEL to a high level. The selection transistor 405 goes from the off state to the on state. An N signal is output to the aperture output line 406 according to the reset voltage of the floating diffusion 402. At the timing t501, the timing generator 206 switches the drive signal φS / H to a high level. The S / H switch 411 goes from the off state to the on state. After that, when the drive signal φS / H is controlled to the Low level, the S / H switch 411 is turned off. The S / H capacitor 412 holds an N signal. At the timing t502, the timing generator 206 starts changing the reference voltage Vslope with a constant slope and starts counting up by the counter 414. At the timing t503, the magnitude relationship between the holding voltage of the N signal and the reference voltage Vslope is reversed. The comparator 413 switches the output to a high level. The counter 414 ends the count-up. As a result, the holding voltage of the N signal is AD-converted to a digital value by counting. The memory / CDS circuit 415 holds the AD-converted N signal. After that, at the timing t504, the timing generator 206 returns the reference voltage Vslope to the maximum value. At timing t505, the timing generator 206 switches the drive signal φTX to a high level. The transfer transistor 401 goes from the off state to the on state. As a result, after the reset, the electric charge generated by the photoelectric conversion of the photodiode 400 is transferred to the floating diffusion 402. An S signal is output to the aperture output line 406. At the timing t506, the timing generator 206 switches the drive signal φS / H to a high level. The S / H capacitor 412 holds the S signal. At the timing t507, the reference voltage Vslope starts to change with a constant slope, and the counter 414 starts counting up. At the timing t508, the magnitude relationship between the holding voltage of the N signal and the reference voltage Vslope is reversed. The comparator 413 switches the output to a high level. The counter 414 ends the count-up. As a result, the holding voltage of the S signal is AD-converted to a digital value by counting. The memory / CDS circuit 415 holds the AD-converted S signal. After that, at the timing t509, the timing generator 206 returns the reference voltage Vslope to the maximum value. The read circuit 305 subtracts the value of the N signal from the value of the S signal held in the memory / CDS circuit 415. The read circuit 305 outputs an SN signal to the signal processing circuit 207. The read circuit 305 outputs an SN signal to the signal processing circuit 207 as pixel data corresponding to the amount of charge generated by the photoelectric conversion of the photodiode 400 of the aperture pixel 302. The above description is for the case where the timing generator 206 controls the first switch 408 and the second switch 409 in the off state. The timing generator 206 can control the first switch 408 and the second switch 409 in the ON state. In this case, the read circuit 305 can output the SN signal of the light-shielding pixel 303 to the signal processing circuit 207 under the same control as in FIG.

FIG. 7 is a timing chart of a process of reading signals as pixel data of a plurality of pixels when the image sensor 100 of FIG. 3 outputs one frame of image data. FIG. 7A is a timing chart for the uppermost opening block 304 and the read circuit 305 (0,0) in the leftmost row of FIG. FIG. 7B is a timing chart for the lowermost opening block 304 and the reading circuit 305 (0,3) in the leftmost row of FIG. FIG. 7C is a timing chart for the uppermost opening block 304 and the read circuit 305 (1,0) in the second row from the left in FIG. FIG. 7D is a timing chart for the lowermost opening block 304 and the reading circuit 305 (1, 3) in the second row from the left in FIG. FIG. 7 (E) is a timing chart for the uppermost opening block 304 and the read circuit 305 (2,0) in the third row from the left in FIG. FIG. 7 (F) is a timing chart for the lowermost opening block 304 and the read circuit 305 (2, 3) in the third row from the left in FIG. FIG. 7 (G) is a timing chart for the lowermost opening block 304 and the read circuit 305 (5, 3) in the rightmost row of FIG. FIG. 7H is a drive signal φSW that controls the on / off state of the first switch 408 and the second switch 409. FIG. 7 (I) is an output signal of the image sensor 100.

The timing generator 206 starts an operation of outputting an image of one frame based on an image acquisition instruction from the overall control calculation unit 103 of the image pickup apparatus 1. The timing generator 206 controls the drive signal φSW to a high level at the timing t510 to turn on the first switch 408 and the second switch 409. As a result, the light-shielding output line 407 of the light-shielding block 306 and the aperture output lines 406 of the plurality of opening blocks 304 arranged in the row direction are connected to each other by the first switch 408 and the second switch 409. At the same time, the timing generator 206 reads out the signal of the pixel data of the light-shielding pixel 303. The opening block 304 and the reading circuit 305 of each set output the signal of the pixel data of the light-shielding pixel 303 by the processing of FIG. The read circuit 305 outputs a signal corresponding to the electric charge due to the dark current stored in the photodiode 400 of the light-shielding pixel 303. The signal processing circuit 207 acquires the SN signal as the pixel data of the light-shielding pixel 303 and holds it as a correction value for the clamping process. The read circuit 305 reads a signal from the light-shielding pixel 303 before reading the signal from the aperture pixel 302 of the corresponding aperture block 304. After that, the timing generator 206 controls the drive signal φSW to a low level at the timing t511 to turn off the first switch 408 and the second switch 409. At the same time, the timing generator 206 reads the pixel data signal of the first aperture pixel 302 from the plurality of aperture blocks 304. The opening block 304 and the reading circuit 305 of each set output the signal of the pixel data of the first opening pixel 302 of the opening block 304 by the process of FIG. The signal processing circuit 207 corrects the pixel data of the aperture pixel 302 with the pixel data of the holding light-shielding pixel 303. The image sensor 100 outputs the signal of the pixel data of the corrected aperture pixel 302 after the timing t512. Further, the timing generator 206 reads out the pixel data signals of the other aperture pixels 302 from the aperture block 304 at the timings t512, ..., T513 following the timing t511. The timing generator 206 reads a pixel data signal from all the aperture pixels 302 of the aperture block 304. After the timing t514, the image sensor 100 outputs the pixel data of the last aperture pixel 302. The image sensor 100 outputs pixel data of a plurality of aperture images for one frame constituting one image. By reading out the plurality of aperture pixels 302 in parallel for each aperture block 304 in this way, the image sensor 100 can output the pixel data of all the aperture pixels 302 in a short time. By the way, as shown in FIG. 7, the timing generator 206 makes the period t510 to t511 for reading the pixel data of the light-shielding pixel 303 longer than the period t511 to t512 for reading the aperture pixel 302 pixel data. The signal of the light-shielding pixel 303 is read through, for example, a light-shielding output line 407, a first switch 408, an opening output line 406 of another opening block 304, a second switch 409, and an opening output line 406 of its own opening block 304. Is output to. As a result, even if the drive load of the amplification transistor 404 of the light-shielding pixel 303 increases and it takes time for the signal voltage to stabilize, the read circuit 305 can read a stable signal. The read circuit 305 reads the signal from the light-shielding pixel 303 for a longer period than when the signal is read from the aperture pixel 302 of the corresponding aperture block 304.

As described above, in the present embodiment, the light-shielding output line 407 of the light-shielding block 306 including the light-shielding pixel 303 and the aperture output line 406 of the aperture block 304 not including the light-shielding pixel 303 are connected by the first switch 408. .. Therefore, the read circuit 305 corresponding to the aperture block 304 can read a signal from the light-shielding pixel 303 included in the light-shielding block 306 through the light-shielding output line 407, the first switch 408, and the aperture output line 406. In the present embodiment, the opening output line 406 of the opening block 304 connected to the light-shielding output line 407 of the light-shielding block 306 by the first switch 408 and the opening output line 406 of the second opening block 304 are second. Connected by switch 409. Therefore, the read circuit 305 is transmitted from the light-shielding pixel 303 through the light-shielding output line 407, the first switch 408, the aperture output line 406 of the other opening block 304, the second switch 409, and the aperture output line 406 of its own opening block 304. The signal can be read. By reading the signal from one light-shielding pixel 303 in this way, the signal can be read from the light-shielding pixel 303 under the same conditions as when reading the signal from the aperture pixel 302. A signal that is considered to be affected by noise equivalent to that of the aperture pixel 302 can be read from the light-shielding pixel 303.

In this embodiment, the read circuit 305 reads a signal from the light-shielding pixel 303 before reading the signal from the aperture pixel 302 of the corresponding aperture block 304. Therefore, the signal processing circuit 207 connected to the read circuit 305 corrects the AD conversion value based on the aperture pixel 302 output from the read circuit 305 according to the AD conversion value based on the light-shielding pixel 303 read earlier. Can be done. In the present embodiment, the clamping process can be appropriately performed without adding a frame memory or the like. In particular, a large number of read circuits 305 provided corresponding to the aperture block 304 perform AD conversion of the signal of the light-shielding pixel 303 in parallel. Thereby, in the present embodiment, the error caused by the noise generated in the read circuit 305 can be averaged. In the present embodiment, by reading the signals from the plurality of light-shielding pixels 303 collectively, it is possible to read out the signal considered to be affected by the average noise in the plurality of light-shielding pixels 303 from the light-shielding pixels 303. In the present embodiment, accurate clamping processing can be performed. The black level error inherent in the read circuit 305 can be removed.

In the present embodiment, the wiring from the light-shielding output line 407 to the aperture output line 406 of the second aperture block 304, which is the signal reading path from the light-shielding pixel 303, can be suppressed to the minimum necessary. Therefore, the signal read from the light-shielding pixel 303 can be appropriately read with a read period slightly longer than the signal read from the aperture pixel 302, even if it is affected by the wiring capacitance or the like. In the present embodiment, the read circuit 305 corresponding to the first opening block 304 and the read circuit 305 corresponding to the second opening block 304 simultaneously read signals from the common light-shielding pixel 303. As a result, a plurality of signals read from the light-shielding pixel 303 can be obtained in a short period equivalent to the case where one signal is read from the light-shielding pixel 303. According to the image pickup apparatus 1 of the present embodiment, the signal of the light-shielding pixel 303 is read out prior to the signal reading of the aperture pixel 302. Thereby, in the present embodiment, the image sensor 100 in which the read circuit 305 is correspondingly arranged for each aperture block 304 can be appropriately corrected by using the black reference signal of the light-shielding pixel 303.

The reading circuit 305 may read a plurality of pixel data from the plurality of light-shielding pixels 303. The signal processing circuit 207 may be provided so as to have a one-to-one correspondence with the reading circuit 305. In this case, the signal processing circuit 207 will perform the clamping process for each corresponding read circuit 305. The clamping process by the signal processing circuit 207 may be executed not by the image sensor 100 but by the overall control calculation unit 103 of the image pickup device 1. The signal processing circuit 207 or the overall control calculation unit 103 determines the difference between the pixel data of the aperture pixels 302 and the pixel data of the light-shielding pixels 303 in the captured image output by the image pickup device 1 in a state where the plurality of aperture pixels 302 are shielded from light. May be corrected by.

[Second Embodiment]
Next, the image pickup apparatus 1 according to the second embodiment of the present invention will be described. In the following description, the differences from the image pickup apparatus 1 of the above-described embodiment will be mainly described.

FIG. 8 is a functional layout diagram of the image sensor 100 according to the second embodiment of the present invention. In the image pickup device 100 of FIG. 8, light-shielding regions 700 are provided above and below the plurality of opening blocks 704 arranged in a matrix on the pixel substrate 200. The aperture block 704 includes a plurality of aperture pixels 702. In FIG. 8, the opening blocks 704 are arranged in 8 rows × 12 columns. In the light-shielding region 700, a plurality of light-shielding blocks 706 having the same number of columns as the opening block 704 are arranged in one row in the row direction. The plurality of read circuits 705 are provided in the read substrate 201 in correspondence with the plurality of opening blocks 704. In FIG. 8, the central position 707 of the opening region 701 and the reading region 205 in the column direction is shown by a broken line for the purpose of explaining the circuit configuration described later. The read circuit 705 above the central position 707 reads the signal of the light-shielding pixel 703 from the light-shielding region 700 on the upper side. The read circuit 705 below the central position 707 reads the signal of the light-shielding pixel 703 from the light-shielding region 700 below.

FIG. 9 is an explanatory diagram of a circuit mounted on the image sensor 100 of FIG. In FIG. 9, among the circuits of the image sensor 100 of FIG. 8, aperture pixels 702, light-shielding pixels 703, read-out circuits 705, and signal processing circuits 207 for a plurality of aperture blocks 704 arranged in the column direction as an example are shown. It is shown. A plurality of light-shielding pixels 703 are arranged in the row direction in the light-shielding block 706 on the upper side. The light-shielding block 706 has a plurality of light-shielding output lines 801 for each light-shielding pixel 703. The light-shielding output line 801 is connected to one light-shielding pixel 703 in the light-shielding block 706. The aperture block 704 has an aperture output line 800 for each row of the plurality of aperture pixels 702. Each light-shielding output line 801 is connected to the opening output line 800 of the adjacent opening block 704 by the upper first switch 802. The light-shielding output line 801 and the first switch 802 and the aperture output line 800 are provided in a plurality of sets. The read circuit 705 includes a plurality of column selection switches (CSW) 804, which are individually connected to the plurality of aperture output lines 800. The column selection switch 804 connects the aperture output line 800 and the S / H switch 411. The opening output line 800 of the opening block 704 above the central position 707 is connected to the opening output line 800 of the opening block 704 directly above by the second switch 803. The light-shielding block 706 and the opening block 704 below the central position 707 are also connected in the same manner as above. The second switch 803 is not formed at the central position 707. The aperture output line 800 is divided into upper and lower parts of the central position 707 for each row by the first switch 802 and the second switch 803, and is connected to the light-shielding output line 801. Here, the aperture output lines 800 arranged in four rows in the aperture block 704 are designated by the symbols (0) to (3) in order from the left when distinguishing them from each other. The same applies to the drive signal φCSW of the light-shielding output line 801, the first switch 802, the second switch 803, the row selection switch 804, and the row selection switch 804. The first switches 802 (0) to (3) and the second switches 803 (0) to (3) are controlled by a common drive signal φSW. The column selection switches 804 (0) to (3) input the same drive signals φCSW (0) to (3) to the read circuits 705 arranged in the row direction.

FIG. 10 is a timing chart of a process of reading signals from a plurality of pixels in the entire image sensor 100 of FIG. FIG. 10A is a timing chart for the uppermost opening block 704 and the read circuit 705 (0,0) in the leftmost row of FIG. FIG. 10B is a timing chart for the second opening block 704 and the read circuit 705 (0,1) from the top in the leftmost row of FIG. FIG. 10C is a timing chart for the fourth opening block 704 and the read circuit 705 (0,3) from the top in the leftmost row of FIG. FIG. 10D is a timing chart for the fifth opening block 704 and the read circuit 705 (0,4) from the top in the leftmost column of FIG. FIG. 10E is a timing chart for the eighth opening block 704 and the read circuit 705 (0,7) from the top in the leftmost row of FIG. FIG. 10F is a drive signal φSW that controls the on / off state of the first switch 802 and the second switch 803. FIG. 10 (G) is an output signal of the image sensor 100.

The timing generator 206 starts an operation of outputting an image of one frame based on an image acquisition instruction from the overall control calculation unit 103 of the image pickup apparatus 1. The timing generator 206 controls the drive signal φSW to a high level at the timing t910 to turn on the first switch 802 and the second switch 803. As a result, the light-shielding output line 801 of the light-shielding block 706 and the aperture output lines 800 of the plurality of opening blocks 704 arranged in the row direction are connected to each other by the first switch 802 and the second switch 803. At the same time, the timing generator 206 turns on the column selection switches 804 corresponding to different columns in the plurality of read circuits 705. As a result, the plurality of read circuits 705 simultaneously read the pixel data signal from the light-shielding pixels 703 in different rows. The opening block 704 and the reading circuit 705 of each set output the signal of the pixel data of the light-shielding pixels 703 in different rows from each other by the processing of FIG. The read circuit 705 outputs a signal corresponding to the electric charge due to the dark current stored in the photodiode 400 of the light-shielding pixel 703. The signal processing circuit 207 acquires the SN signal as the pixel data of the light-shielding pixel 703 and holds it as a correction value for the clamping process. The read circuit 705 reads a signal from the light-shielding pixel 703 before reading the signal from the aperture pixel 702 of the corresponding aperture block 704.

After that, the timing generator 206 controls the drive signal φSW to a low level at the timing t901 to turn off the first switch 802 and the second switch 803. At the same time, the timing generator 206 starts reading the signal of the pixel data of the aperture pixels 702 from the plurality of aperture blocks 704. The opening block 704 and the reading circuit 705 of each set output the signal of the pixel data of the plurality of opening pixels 702 of the opening block 704 by the processing of FIG. 6 for each opening pixel 702. The signal processing circuit 207 corrects the pixel data of the aperture pixel 702 with the pixel data of the holding light-shielding pixel 703. The image sensor 100 outputs a signal of pixel data of the corrected aperture pixel 702. After the timing t902, the image sensor 100 outputs the pixel data of the last aperture pixel 702. The image sensor 100 outputs pixel data of a plurality of aperture images for one frame constituting one image. By reading out the plurality of aperture pixels 702 in parallel for each aperture block 704 in this way, the image sensor 100 can output the pixel data of all the aperture pixels 702 in a short time.

As described above, in the present embodiment, the plurality of read circuits 705 arranged in the column direction have a plurality of column selection switches 804 connected to a plurality of aperture output lines 800 different from each other. Therefore, the plurality of read circuits 705 can switch the row selection switches 804 in different rows to the ON state and read signals from the light-shielding pixels 703 in different rows. For example, the read circuit 705 corresponding to the opening block 704 at the top of the row and the read circuit 705 corresponding to the opening block 704 below it read signals from different light-shielding pixels 703 at the same time. Thereby, in the present embodiment, a plurality of signals read from the plurality of light-shielding pixels 703 can be obtained in a short period equivalent to the case where one signal is read from the light-shielding pixels 703. As a result, in the present embodiment, signals can be simultaneously read from all the light-shielding pixels 703 by using a plurality of read circuits 705 arranged in a matrix. In the present embodiment, signals can be read out from all the light-shielding pixels 703 in a short time. Thereby, in this embodiment, the number of light-shielding pixels 703 used for generating the correction value of the clamping process can be increased. In the present embodiment, for example, by using the average value of a plurality of light-shielding pixels 703 for correction, it is possible to reduce the characteristic variation of each light-shielding pixel 703 and improve the estimation accuracy of the dark current related to the correction.

[Third Embodiment]
Next, the image pickup apparatus 1 according to the third embodiment of the present invention will be described. In the following description, the differences from the image pickup apparatus 1 of the above-described embodiment will be mainly described.

FIG. 11 is a functional layout diagram of the image sensor 100 according to the third embodiment of the present invention. The image sensor 100 of FIG. 11 is provided with a light-shielding region 1000 on the upper side of a plurality of aperture blocks 1004 arranged in a matrix on the pixel substrate 200. In FIG. 11, the opening blocks 1004 are arranged in 8 rows × 12 columns. In the light-shielding region 1000, a plurality of light-shielding blocks 1006 having the same number of columns as the opening block 1004 are arranged in a plurality of rows. In FIG. 11, the shading pixels 1003 are arranged in 4 rows × 24 columns. When the light-shielding pixels 1003 are distinguished from each other, the symbols (0,0) to (23,3) of the respective arrangement positions are attached. The plurality of read circuits 1005 are provided in the read substrate 201 in correspondence with the plurality of opening blocks 1004.

FIG. 12 is an explanatory diagram of a circuit mounted on the image pickup device 100 of FIG. In FIG. 12, among the circuits of the image pickup device 100 of FIG. 11, the aperture pixels 1002, the light-shielding pixels 1003, the read circuit 1005, and the signal processing circuit 207 for a plurality of aperture blocks 1004 arranged in the column direction as an example are shown. It is shown. A plurality of light-shielding pixels 1003 are arranged in a matrix in the light-shielding block 1006. The light-shielding pixels 1003 are arranged in 4 rows × 2 columns in the light-shielding block 1006. The light-shielding block 1006 has a plurality of light-shielding output lines 1101 for each row of light-shielding pixels 1003. The light-shielding output line 1101 is connected to a plurality of light-shielding pixels 1003 in each row in the light-shielding block 1006. The aperture block 1004 has an aperture output line 1100 for each row of the plurality of aperture pixels 1002. Here, the aperture block 1004 has 2 rows × 2 columns of aperture pixels 1002. Each light-shielding output line 1101 is connected to an opening output line 1100 of an opening block 1004 adjacent to each other in the row direction by a first switch 1102. The light-shielding output line 1101, the first switch 1102, and the aperture output line 1100 are provided in a plurality of sets. The read circuit 1005 has a plurality of column selection switches (CSW) 1104, which are individually connected to the plurality of aperture output lines 1100. The column selection switch 1104 connects the aperture output line 1100 and the S / H switch 411. The opening output line 1100 of the opening block 1004 second from the top and the opening block 1004 below it is connected to the opening output line 1100 of the opening block 1004 directly above by the second switch 1103. The aperture output line 1100 is connected to the light-shielding output line 1101 for each row by the first switch 1102 and the second switch 1103. Here, the aperture output lines 1100 arranged in two rows in the aperture block 1004 are designated by the symbols (0) to (1) in order from the left when distinguishing them from each other. The same applies to the drive signal φCSW of the light-shielding output line 1101, the first switch 1102, the second switch 1103, the column selection switch 1104, and the column selection switch 1104. The first switches 1102 (0) to (1) and the second switches 1103 (0) to (1) are controlled by a common drive signal φSW. The column selection switches 1104 (0) to (1) receive the same drive signals φCSW (0) to (1) to the read circuits 1005 arranged in the row direction.

FIG. 13 is a timing chart of a process of reading signals from a plurality of pixels in the entire image sensor 100 of FIG. FIG. 13A is a timing chart for the first opening block 1004 and the read circuit 1005 (0,0) from the top in the leftmost row of FIG. FIG. 13B is a timing chart for the second opening block 1004 and the read circuit 1005 (0,1) from the top in the leftmost row of FIG. FIG. 13C is a timing chart for the third opening block 1004 and the read circuit 1005 (0,2) from the top in the leftmost row of FIG. FIG. 13 (D) is a timing chart for the fourth opening block 1004 and the read circuit 1005 (0,3) from the top in the leftmost row of FIG. FIG. 13 (E) is a timing chart for the seventh opening block 1004 and the read circuit 1005 (0,6) from the top in the leftmost row of FIG. FIG. 13 (F) is a timing chart for the eighth opening block 1004 and the read circuit 1005 (0,7) from the top in the leftmost row of FIG. FIG. 13 (G) is a drive signal φSW that controls the on / off state of the first switch 1102 and the second switch 1103. FIG. 13H is an output signal of the image sensor 100.

The timing generator 206 starts an operation of outputting an image of one frame based on an image acquisition instruction from the overall control calculation unit 103 of the image pickup apparatus 1. At timings t1200 to t1202, the timing generator 206 reads a signal from the light-shielding pixel 1003 by a plurality of reading circuits 1005 before reading the signal from the aperture pixel 1002 of the corresponding aperture block 1004. The timing generator 206 controls the drive signal φSW to a high level to turn on the first switch 1102 and the second switch 1103. As a result, the light-shielding output line 1101 of the light-shielding block 1006 and the aperture output lines 1100 of the plurality of opening blocks 1004 arranged in the row direction are connected to each other by the first switch 1102 and the second switch 1103. At the same time, the timing generator 206 turns on the column selection switch 1104 corresponding to the left column in the read circuit 1005 corresponding to the first opening block 1004 from the top. Further, the timing generator 206 turns on the column selection switch 1104 corresponding to the right column in the read circuit 1005 corresponding to the second opening block 1004 from the top. The timing generator 206 turns on the column selection switches 1104 corresponding to different columns in the plurality of read circuits 1005 that read simultaneously. Further, the timing generator 206 outputs the drive signal CSW to the column selection switches 1104 (0) and 1104 (1) of the read circuit 1005, and drives the light-shielding pixels 1003 in the first row of the light-shielding block 1006. As a result, the plurality of reading circuits 1005 simultaneously read the pixel data signals from the light-shielding pixels 1003 in different columns in the first row of the light-shielding block 1006. The two sets of the aperture block 1004 and the reading circuit 1005 output the signal of the pixel data of the light-shielding pixels 1003 in different columns in the first row of the light-shielding block 1006 by the processing of FIG. The read circuit 1005 outputs a signal corresponding to the electric charge due to the dark current stored in the photodiode 400 of the light-shielding pixel 1003. The signal processing circuit 207 acquires the SN signal as the pixel data of the two light-shielding pixels 1003 in the first line of the light-shielding block 1006 and holds it as a correction value for the clamping process.

At the timing t1201, the timing generator 206 turns on the column selection switch 1104 corresponding to the left column in the read circuit 1005 corresponding to the third opening block 1004 from the top. Further, the timing generator 206 turns on the column selection switch 1104 corresponding to the right column in the read circuit 1005 corresponding to the fourth opening block 1004 from the top. The timing generator 206 turns on the column selection switches 1104 corresponding to different columns in the plurality of read circuits 1005 that read simultaneously. Further, the timing generator 206 outputs the drive signal CSW to the column selection switches 1104 (2) and 1104 (3) of the read circuit 1005, and drives the light-shielding pixel 1003 in the second row of the light-shielding block 1006. As a result, the plurality of reading circuits 1005 simultaneously read the pixel data signal from the light-shielding pixels 1003 in different columns in the second row of the light-shielding block 1006. The two sets of the aperture block 1004 and the reading circuit 1005 output the signal of the pixel data of the light-shielding pixels 1003 in different columns in the second row of the light-shielding block 1006 by the process of FIG. The read circuit 1005 outputs a signal corresponding to the electric charge due to the dark current stored in the photodiode 400 of the light-shielding pixel 1003. The signal processing circuit 207 acquires the SN signal as the pixel data of the light-shielding pixel 1003 and holds it as a correction value for the clamping process. As described above, the timing generator 206 selects the reading circuits 1005 corresponding to the plurality of opening blocks 1004 in each row by sequentially switching two from the top in order to read the pixel data of the light-shielding pixels 1003. Further, the timing generator 206 switches the light-shielding pixel 1003 driven by the light-shielding block 1006. As a result, at the timing t1202, all the read circuits 1005 read the signal of the pixel data of the light-shielding pixels 1003 in all the rows and all columns of the light-shielding block 1006. The read circuit 1005 outputs a signal corresponding to the electric charge due to the dark current stored in the photodiode 400 of the light-shielding pixel 1003. The signal processing circuit 207 acquires the SN signal as pixel data of all the light-shielding pixels 1003 and holds it as a correction value for the clamping process. The signal processing circuit 207 holds, for example, an average value of SN signals as pixel data of all the light-shielding pixels 1003 as a correction value for clamping processing. By averaging the pixel data of the light-shielding pixels 1003 in the calculation of the clamp value, it is possible to reduce the error of noise for each read circuit 1005, and accurate clamping processing can be expected.

After that, the timing generator 206 controls the drive signal φSW to a low level at the timing t901 to turn off the first switch 1102 and the second switch 1103. At the same time, the timing generator 206 starts reading the signal of the pixel data of the aperture pixels 1002 from the plurality of aperture blocks 1004. The opening block 1004 and the reading circuit 1005 of each set output the signal of the pixel data of the plurality of opening pixels 1002 of the opening block 1004 by the processing of FIG. 6 for each opening pixel 1002. The signal processing circuit 207 corrects the pixel data of the aperture pixel 1002 with the pixel data of the holding light-shielding pixel 1003. The image sensor 100 outputs a signal of pixel data of the corrected aperture pixel 1002. After the timing t902, the image sensor 100 outputs the pixel data of the last aperture pixel 1002. The image sensor 100 outputs pixel data of a plurality of aperture images for one frame constituting one image. By reading out the plurality of aperture pixels 1002 in parallel for each aperture block 1004 in this way, the image pickup element 100 can output the pixel data of all the aperture pixels 1002 in a short time.

As described above, in the present embodiment, during the signal processing of the read circuit 1005 that has read the signal of the light-shielding pixel 1003 immediately before, the next read circuit 1005 reads the signal from the next light-shielding pixel 1003. As a result, in the present embodiment, although the signal from the light-shielding pixel 1003 is read out a plurality of times, the reading and processing are executed over time, and the total period t1200 to t1202 is shortened. can do. As a result, in the present embodiment, all the light-shielding pixels 1003 can be read out in a short time without limiting the relationship between the number of light-shielding pixels 1003 arranged, the number of aperture output lines 1100, and the number of reading circuits 1005 arranged. It is possible.

In this embodiment, the read circuit 1005 used for reading the light-shielding pixel 1003 is sequentially switched, but the present invention is not limited to this. For example, the read circuit 1005 close to the light-shielding region 1000 may continue to be used for reading the light-shielding pixels 1003. As a result, it is not necessary to provide the second switch 1103 for the read circuit 1005 that is not used for reading the light-shielding pixel 1003. The output load of the amplification transistor 404 of the light-shielding pixel 1003 can be reduced. The period required for reading the signal from the light-shielding pixel 1003 can be shortened. The number of rows and columns of the light-shielding pixel 1003 in the light-shielding pixel 1003 area 202 is not limited to this embodiment.

Although the present invention has been described in detail based on the preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various embodiments within the scope of the gist of the present invention are also included in the present invention. included.

The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors of the computer of the system or device reads the program. It can also be realized by the processing to be executed. The present invention can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

1 Imaging device 100 Imaging element 200 Pixel board 201 Read board 206 Timing generator 207 Signal processing circuit 302, 702, 1002 Aperture pixel 303, 703, 1003 Shading pixel 304, 704, 1004 Aperture block 305, 705, 1005 Read circuit 306, 706 , 1006 Shading block 406,800,1100 Opening output line 407,801,1101 Shading output line 408,802,1102 First switch 409,803,1103 Second switch 600 Clamp value generator 601 Subtraction circuit 804,1104 Column selection switch

Claims (14)

A first substrate on which a plurality of pixels including light-shielding pixels and aperture pixels for photoelectric conversion are arranged,
A plurality of output lines are provided for each of a plurality of blocks that separate at least a light-shielding pixel and a part of the aperture pixels, and are connected to the plurality of pixels included in the block.
A read circuit provided corresponding to the aperture block which is the block that does not include the light-shielding pixel and reads a signal from a plurality of pixels included in the aperture block through the output line.
A first switch that connects the light-shielding output line, which is the output line of the light-shielding block, which is the block including the light-shielding pixel, and the aperture output line, which is the output line of the aperture block.
Have,
The reading circuit corresponding to the aperture block reads a signal from the shading pixels included in the shading block through the shading output line, the first switch, and the aperture output line.
Image sensor. It has a second switch that connects the opening output line of the first opening block and the opening output line of the second opening block, which are connected to the light-shielding output line of the light-shielding block by the first switch. And
The read circuit corresponding to the second opening block is the light-shielding output line, the first switch, the opening output line of the first opening block, the second switch, and the second opening block. A signal is read from the light-shielding pixels included in the light-shielding block through the aperture output line.
The image pickup device according to claim 1. The shading output line is connected to one shading pixel in the shading block.
The image pickup device according to claim 1 or 2. The shading output line is connected to a plurality of shading pixels in the shading block.
The image pickup device according to claim 1 or 2. The light-shielding output line, the first switch, and the aperture output line are provided in a plurality of sets.
The read circuit has a plurality of selection switches, which are connected to the plurality of aperture output lines.
The image pickup device according to any one of claims 1 to 4. The read circuit reads a signal from the light-shielding pixel before reading the signal from the aperture pixel of the corresponding aperture block.
The image pickup device according to any one of claims 1 to 5. The read circuit AD-converts the read signal and converts it.
It has a signal processing circuit that is connected to the read circuit and corrects an AD conversion value based on the aperture pixel output from the read circuit according to an AD conversion value based on the light-shielding pixel.
The image pickup device according to any one of claims 1 to 6. The light-shielding block, the first opening block connected to the light-shielding block by the first switch, and the second opening block connected to the first opening block by the second switch are described as described above. Provided side by side on the first substrate,
The image pickup device according to claim 2. The read circuit corresponding to the first opening block and the read circuit corresponding to the second opening block can simultaneously read a signal from the common light-shielding pixel.
The image pickup device according to claim 2 or 8. The read circuit corresponding to the first opening block and the read circuit corresponding to the second opening block can simultaneously read signals from different light-shielding pixels.
The image pickup device according to claim 2 or 8. The read circuit corresponding to the second opening block outputs a signal from the light-shielding pixel during signal processing after the read circuit corresponding to the first opening block reads a signal from the light-shielding pixel. Can be read,
The image pickup device according to claim 2 or 8. The read circuit reads a signal from the light-shielding pixel for a longer period than when the signal is read from the aperture pixel of the corresponding aperture block.
The image pickup device according to any one of claims 1 to 11. A method of reading an image sensor, wherein a plurality of pixels including a light-shielding pixel and an aperture pixel for photoelectric conversion are separately provided as an aperture block not including the light-shielding pixel and a light-shielding block including the light-shielding pixel.
The light-shielding output line for reading a signal from the light-shielding pixel of the light-shielding block and the aperture output line for reading a signal from the aperture pixel of the aperture block are connected by a first switch, and the light-shielding output line and the first switch And the process of reading a signal from the light-shielding pixel through the aperture output line,
A step of reading a signal from the aperture pixel of the aperture block through the aperture output line with the first switch open, and
A method for reading an image sensor. An image pickup apparatus including an image pickup element for photoelectric conversion and a control unit for controlling reading by the image pickup element (by instructing the image pickup element to read out).
The image sensor is
A first substrate on which a plurality of pixels including light-shielding pixels and aperture pixels for photoelectric conversion are arranged,
A plurality of output lines are provided for each of a plurality of blocks that separate at least a light-shielding pixel and a part of the aperture pixels, and are connected to the plurality of pixels included in the block.
A read circuit provided corresponding to the aperture block which is the block that does not include the light-shielding pixel and reads a signal from a plurality of pixels included in the aperture block through the output line.
A first switch that connects the light-shielding output line, which is the output line of the light-shielding block, which is the block including the light-shielding pixel, and the aperture output line, which is the output line of the aperture block.
Have,
The read circuit corresponding to the aperture block reads a signal from the light-shielding pixels included in the light-shielding block through the light-shielding output line, the first switch, and the aperture output line.
Imaging device.