JP2019208221A - Imaging device and imaging apparatus - Google Patents

Abstract

To provide an imaging device and an imaging apparatus capable of obtaining an accurate output reference level for a pixel in an effective pixel region for reading a pixel signal.SOLUTION: An imaging device 10 includes at least two photoelectric conversion blocks 12 capable of reading signals independently of each other in a photoelectric conversion region 11. Each of the at least two photoelectric conversion blocks 12 includes: a plurality of photoelectric conversion pixel units 20-1 to 20-3 each including a photoelectric conversion unit that accumulates electric charges photoelectrically converted according to an amount of incident light to the photoelectric conversion region 11; and at least one reference pixel units 22-3 that generate a voltage reference level that does not depend on an amount of incident light to the photoelectric conversion region.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an imaging element and an imaging apparatus.

Conventionally, an optical black area has been provided in an area close to the effective pixel area of the image sensor and different from the effective pixel area (see, for example, Patent Document 1). In addition, it has been proposed to provide at least one optical black pixel in the effective pixel region (see, for example, Patent Document 2).
[Prior art documents]
[Patent Literature]
[Patent Literature 1] JP 2012-124213 A [Patent Literature 2] JP 2013-118573 A

  However, if an optical black region is provided in a region different from the effective pixel region, the area of the image sensor increases. In addition, since the position of the pixel from which the pixel signal is read and the position of the optical black region are spatially separated, there are the following problems when the pixel signal is read by the block division method.

  First, there is a problem that a difference occurs between the output reference level of the optical black region and the output reference level to be detected at the pixel position where the pixel signal is read. Further, when the charge accumulation time is changed for each block, there is a problem in that the output reference level of the optical black region must be corrected and used as the output reference level in accordance with the change in the charge accumulation time.

  Even when at least one optical black pixel is provided in the effective pixel area, if the optical black pixel is not provided in the vicinity of the pixel from which the pixel signal is read, an accurate output reference level is detected. Difficult to do.

  In the first aspect of the present invention, the photoelectric conversion region in which a plurality of photoelectric conversion units are arranged includes at least two photoelectric conversion blocks capable of reading signals independently of each other, and includes at least two photoelectric conversion blocks. Each includes a plurality of photoelectric conversion pixel units each including a photoelectric conversion unit that accumulates charges photoelectrically converted according to the amount of light incident on the photoelectric conversion region, and a voltage reference level independent of the amount of light incident on the photoelectric conversion region. An imaging device having at least one reference pixel unit to be generated is provided.

  According to a second aspect of the present invention, there is provided an imaging device comprising the above-described imaging device.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

2 is a cross-sectional view of a single-lens reflex camera 400. FIG. It is a figure which shows the photoelectric conversion area | region 11 of the image pick-up element 10 in 1st Embodiment, and the partial area | region 14 of the photoelectric conversion block 12. FIG. 4 is a schematic diagram showing a part of an image sensor unit 200, a part of an image processing ASIC 624, and a part of a CPU 622. 3 is a timing chart showing the operation of one photoelectric conversion block 12; It is a figure which shows the partial area | region 14 of the photoelectric conversion block 12 in 2nd Embodiment. It is a figure which shows the partial area | region 14 of the photoelectric conversion block 12 in 3rd Embodiment. It is a figure which shows the partial area | region 14 of the photoelectric conversion block 12 in 4th Embodiment. 3 is an enlarged view of a region 30. FIG. It is a schematic diagram which shows the 1st reference pixel part 24 and the 2nd reference pixel part 26 in a BB cross section.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a cross-sectional view of a single-lens reflex camera 400. A single-lens reflex camera 400 as an imaging apparatus includes an imaging element unit 200. The image sensor unit 200 includes an image sensor. The single-lens reflex camera 400 includes a lens unit 500 and a camera body 600. A lens unit 500 is attached to the camera body 600. The lens unit 500 includes an optical system arranged along the optical axis 410 in the lens barrel, and guides an incident subject light beam to the image sensor unit 200 of the camera body 600.

  Note that in this specification, the first direction is perpendicular to the second direction. The first direction may be the column direction of the image sensor in the image sensor unit 200, and the second direction may be the row direction of the image sensor in the image sensor unit 200. The first direction may be the so-called x direction of the image sensor, and the second direction may be the so-called y direction of the image sensor. Furthermore, the first direction may be read as the vertical direction of the image sensor, and the second direction may be read as the horizontal direction of the image sensor. The third direction is a direction perpendicular to the plane defined by the first direction and the second direction. The third direction is parallel to the optical axis 410. The third direction may be read as the z direction.

  The camera body 600 includes a main mirror 672 and a sub mirror 674 behind a body mount 660 coupled to the lens mount 550. The main mirror 672 is pivotally supported between an oblique position obliquely provided to the subject light beam incident from the lens unit 500 and a retreat position where the main mirror 672 is retracted from the subject light beam. The sub mirror 674 is pivotally supported with respect to the main mirror 672 so as to be rotatable.

  When the main mirror 672 is in the oblique position, most of the subject light beam incident through the lens unit 500 is reflected by the main mirror 672 and guided to the focus plate 652. The focus plate 652 is disposed at a position conjugate with the light receiving surface of the image sensor, and visualizes the subject image formed by the optical system of the lens unit 500. The subject image formed on the focus plate 652 is observed from the viewfinder 650 through the pentaprism 654 and the viewfinder optical system 656. Part of the subject light beam incident on the main mirror 672 at the oblique position passes through the half mirror region of the main mirror 672 and enters the sub mirror 674. The sub mirror 674 reflects a part of the light beam incident from the half mirror region toward the focusing optical system 680. The focusing optical system 680 guides a part of the incident light beam to the focus detection sensor 682.

  In this example, the phase difference autofocus method is adopted. However, when the image plane phase difference autofocus method is adopted, the sub mirror 674, the focusing optical system 680, and the focus detection sensor 682 can be omitted. Thereby, the volume of the camera body 600 can be reduced as compared with the case of the phase difference autofocus method.

  The focus plate 652, the pentaprism 654, the main mirror 672, and the sub mirror 674 are supported by a mirror box 670 as a structure. The image sensor unit 200 is attached to the mirror box 670. When the main mirror 672 and the sub mirror 674 are retracted to the retracted position and the front curtain and the rear curtain of the shutter unit 340 are in the open state, the subject luminous flux that passes through the lens unit 500 reaches the light receiving surface of the image sensor.

  A body substrate 620 and a rear display unit 634 are sequentially disposed behind the image sensor unit 200. A rear display unit 634 employing a liquid crystal panel or the like appears on the rear surface of the camera body 600. Electronic circuits such as a CPU 622 and an image processing ASIC 624 are mounted on the body substrate 620. The output of the image sensor is delivered to the image processing ASIC 624 via the flexible substrate electrically connected to the glass substrate.

  In the above-described embodiment, the single-lens reflex camera 400 has been described as an example of the imaging apparatus. However, the camera body 600 may be regarded as an imaging apparatus. The imaging device is not limited to the interchangeable lens camera including the mirror unit, but may be a interchangeable lens camera that does not include the mirror unit or a lens-integrated camera regardless of the presence or absence of the mirror unit.

  FIG. 2 is a diagram illustrating the photoelectric conversion region 11 of the image sensor 10 and the partial region 14 of the photoelectric conversion block 12 in the first embodiment. The image sensor 10 has a photoelectric conversion region 11. The photoelectric conversion region 11 has a plurality of photoelectric conversion blocks 12.

  In FIG. 2, the photoelectric conversion block 12 is shown by coordinate display using the first direction and the second direction. In this example, at least two photoelectric conversion blocks 12 may read signals independently of each other. Signals generated by photoelectric conversion in the photoelectric conversion block 12 are read out independently between the photoelectric conversion blocks 12. That is, the signal generated in the photoelectric conversion block 12 is read for each photoelectric conversion block 12 by a so-called block division reading method.

  Each of the photoelectric conversion blocks 12 includes a plurality of photoelectric conversion pixel units 20 and a plurality of reference pixel units 22. A partial region 14 is an enlarged portion of the photoelectric conversion block 12. Note that a photoelectric conversion unit is disposed in each of the plurality of photoelectric conversion pixel units 20. The photoelectric conversion unit accumulates the charge that has been photoelectrically converted according to the amount of light incident on the photoelectric conversion region 11.

  In the present specification, one photoelectric conversion pixel unit 20 includes a filter having a predetermined spectral characteristic and one photoelectric conversion unit. However, when focus detection is performed by the image plane phase difference autofocus method, one photoelectric conversion unit has a plurality of divided photoelectric conversion regions. That is, in the case of the image plane phase difference autofocus method, the photoelectric conversion pixel unit 20 has a smaller area than the photoelectric conversion region of the photoelectric conversion unit that does not perform focus detection on a plane defined by the first direction and the second direction. A plurality of photoelectric conversion regions are provided.

  In the photoelectric conversion region 11, the photoelectric conversion pixel unit 20 having a red filter is replaced by a photoelectric conversion pixel unit 20-1 (or simply an R pixel unit), and the photoelectric conversion pixel unit 20 having a green filter is converted by a photoelectric conversion pixel unit 20. -2 (or simply G pixel portion) and the photoelectric conversion pixel portion 20 having a blue filter are arranged in a Bayer pattern with the photoelectric conversion pixel portion 20-3 (or simply B pixel portion). . However, the color of the filter is an example. So-called cyan, magenta and yellow may be used. Further, the photoelectric conversion pixel units 20-1, 20-2, and 20-3 may be arranged in a stripe pattern instead of the Bayer pattern.

  Each of the photoelectric conversion blocks 12 has at least one reference pixel unit 22. At least one reference pixel unit generates a voltage reference level that does not depend on the amount of light incident on the photoelectric conversion region 11. In this example, the reference pixel unit 22 may include a light shielding layer between the filter and the photoelectric conversion unit. The light shielding layer is different from the light shielding layer for so-called image plane retardation. The light blocking layer is provided for the purpose of blocking all the light incident on the reference pixel portion 22.

  By providing the reference pixel portion 22, it is possible to detect a dark current generated in the image sensor 10. The dark current is noise generated due to heat of the image sensor 10 or charge accumulation time. By subtracting the signal value output from the reference pixel unit 22 from the signal value output from the photoelectric conversion pixel unit 20, the influence of the noise current can be removed.

  In this example, the photoelectric conversion block 12 is provided with at least one reference pixel unit 22. Therefore, when the photoelectric conversion block 12 and the optical black region or the reference pixel unit 22 are provided spatially apart from each other, or compared with the case where the reference pixel unit 22 is not provided in the photoelectric conversion block 12, the photoelectric conversion is performed. The pixel unit 20 is provided in the vicinity of the reference pixel unit 22. Therefore, the reference pixel unit 22 can detect the dark current of the photoelectric conversion pixel unit 20 with higher accuracy.

  In the block division readout method, the charge accumulation time may be changed for each photoelectric conversion block 12. Even in this case, since the reference pixel unit 22 is provided in the photoelectric conversion block 12, the reference pixel unit 22 can detect the dark current in each photoelectric conversion block 12 according to the change of the charge accumulation time. it can. Therefore, the influence of dark current can be accurately removed for each photoelectric conversion block 12.

  The B pixel unit that functions as the reference pixel unit 22 is a reference pixel unit 22-3. In this example, the reference pixel unit 22-3 is arranged every three pixels in the first direction and the second direction in the photoelectric conversion block 12. Therefore, one line in the second direction in which the reference pixel unit 22-3 is provided may be a light shielding line. A plurality of the light shielding lines are provided in the photoelectric conversion block 12.

  Furthermore, in one row in the second direction in which the photoelectric conversion pixel units 20-1 and 20-2 are provided, the photoelectric conversion pixel unit 20-1 or 20-2 may be a phase difference detection pixel unit. That is, one line in the second direction in which the photoelectric conversion pixel units 20-1 and 20-2 are provided may be a focus detection line used for image plane phase difference autofocus. A plurality of the focus detection lines may be provided in the photoelectric conversion block 12.

  As a modification, only the plurality of R pixel portions may be used as the reference pixel portion 22. When the R pixel unit is the reference pixel unit 22, a row in the second direction in which the reference pixel unit 22 is provided is a light shielding line. Note that a plurality of the light shielding lines may be provided in the photoelectric conversion block 12. Furthermore, in one row in the second direction in which the photoelectric conversion pixel units 20-2 and 20-3 are provided, the photoelectric conversion pixel unit 20-2 or 20-3 may be a phase difference detection pixel unit. That is, one line in the second direction in which the photoelectric conversion pixel units 20-2 and 20-3 are provided may be a focus detection line used for image plane phase difference autofocus. A plurality of the focus detection lines may be provided in the photoelectric conversion block 12.

  FIG. 3 is a schematic diagram showing a part of the image sensor unit 200, a part of the image processing ASIC 624, and a part of the CPU 622. The image sensor unit 200 includes the image sensor 10 and a drive circuit 70. The image processing ASIC 624 includes a signal processing unit 60. The CPU 622 has a control unit 80.

  The imaging device 10 includes a photoelectric conversion pixel unit 20, a transfer unit 44, a charge / voltage conversion unit 46, a charge exclusion unit 48, an amplification unit 49, an output unit 50, a high potential unit 52, and a signal line 54. The photoelectric conversion pixel unit 20 includes a color filter 40 and a photoelectric conversion unit 42. In FIG. 3, for example, in the imaging device 10, the three photoelectric conversion pixel units 20, the transfer unit 44, the charge voltage conversion unit 46, the charge exclusion unit 48, the amplification unit 49, the output unit 50, and the high potential unit 52. And a signal line 54 is shown. However, in the image sensor 10, the photoelectric conversion pixel unit 20 and the like are not limited to three.

  The photoelectric conversion unit 42 is provided with a color filter 40 having spectral characteristics in the vicinity thereof. The photoelectric conversion unit 42 generates electric charge according to the amount of light incident through the color filter 40. Further, the photoelectric conversion unit 42 accumulates the photoelectrically converted charges. The accumulated charge is, for example, electrons.

  In this example, the photoelectric conversion pixel units 20-1 (R pixel unit) and 20-2 (G pixel unit) generate charges according to the amount of light incident through the color filter 40. On the other hand, since the reference pixel unit 22-3 (B pixel unit) includes the light shielding layer 90 between the color filter 40-3 and the photoelectric conversion unit 42-3, the charge is generated according to the amount of incident light. do not do.

  The transfer unit 44 is provided between the photoelectric conversion unit 42 and the charge / voltage conversion unit 46. In this example, the transfer unit 44 is a transistor having a gate, a source, and a drain. When the control signal (TX) is supplied from the drive circuit 70 to the gate of the transfer unit 44, the transfer unit 44 transfers the charge accumulated in the photoelectric conversion unit 42 to the charge-voltage conversion unit 46.

  The charge exclusion unit 48 is provided between the high potential unit 52 and the charge voltage conversion unit 46. In this example, the charge exclusion unit 48 is a transistor having a gate, a source, and a drain. When the control signal (RST) is given from the drive circuit 70 to the gate of the charge exclusion unit 48, the charge exclusion unit 48 sets the potential of the charge voltage conversion unit 46 to substantially the same potential as the high potential unit 52. In this example, the charge eliminator 48 excludes electrons accumulated in the charge / voltage converter 46.

  The amplifying unit 49 is provided between the output unit 50 and the high potential unit 52. In this example, the amplification unit 49 is a transistor having a gate, a source, and a drain. The gate of the amplifying unit 49 is electrically connected to the charge / voltage converting unit 46. As a result, the amplifying unit 49 outputs a current to the output unit 50 with the voltage obtained by amplifying the voltage of the charge-voltage converting unit 46.

  The output unit 50 is provided between the amplifying unit 49 and the signal line 54. In this example, the output unit 50 is a transistor having a gate, a source, and a drain. When a control signal (SEL) is given from the drive circuit 70 to the gate of the output unit 50, the output unit 50 outputs a current to the signal line 54 with the voltage amplified by the amplification unit 49. As a result, a signal corresponding to the amplified voltage of the charge-voltage conversion unit 46 is output to the signal line 54 as a signal.

The high potential portion 52 is electrically connected to the power supply voltage (V _DD ). The high potential unit 52 supplies a high potential to the charge exclusion unit 48 and the amplification unit 49. The high potential may be any potential as long as the charge exclusion operation of the charge exclusion unit 48 and the amplification operation of the amplification unit 49 can be executed.

  The charge transferred from the transfer unit 44 is accumulated in the charge-voltage conversion unit 46. In this example, the charge / voltage conversion unit 46 is a so-called floating diffusion region. The charge-voltage converter 46 may be a capacitor having one end electrically connected to the output of the transfer unit 44 and the other end grounded. The charge transferred from the transfer unit 44 is accumulated at the other end of the charge-voltage conversion unit 46. As a result, the charge-voltage converter 46 converts the accumulated charge into a potential. Note that the potential of the gate of the amplifier 49 is equal to the potential of the one end of the charge-voltage converter 46.

  A signal is output from each output unit 50 to the signal line 54. In this example, pixel signals are respectively output from the output unit 50-1 of the photoelectric conversion pixel unit 20-1 (R pixel unit) and the output unit 50-2 of the photoelectric conversion unit 20-2 (G pixel unit) to the signal line 54. -1 and 54-2. On the other hand, a signal corresponding to the voltage level corresponding to the dark current is output from the output unit 50-3 of the reference pixel unit 22-3 (B pixel unit) to the signal line 54-3. The signal line 54 is connected to the signal processing unit 60 via a CDS circuit, an AD conversion circuit, and the like.

  A signal corresponding to the amount of charge photoelectrically converted in the photoelectric conversion pixel unit 20 is output to the signal processing unit 60. Further, a signal corresponding to the dark current detected in the reference pixel unit 22 is output to the signal processing unit 60. The signal processing unit 60 uses a signal corresponding to the dark current as a voltage reference level. The signal processing unit 60 corrects signals output from the plurality of photoelectric conversion pixel units 20 using the voltage reference levels generated in the plurality of reference pixel units 22.

  The signal processing unit 60 generates signals by interpolating signals at the positions of the plurality of reference pixel units 22 using signals output from the plurality of photoelectric conversion pixel units 20 adjacent to each of the plurality of reference pixel units 22. To do. The interpolation method used by the signal processing unit 60 may use an interpolation method based on median processing, an interpolation method based on gradient, or an adaptive color plane interpolation method.

  The drive circuit 70 supplies signal pulses to the gates of the transfer unit 44, the charge exclusion unit 48, and the output unit 50. As a result, the transistors of the transfer unit 44, the charge exclusion unit 48, and the output unit 50 are turned on.

  The control unit 80 controls the drive circuit 70. That is, the control unit 80 controls the transfer unit 44, the charge exclusion unit 48, and the output unit 50 by controlling the pulse timing to the gate of the transfer unit 44, the charge exclusion unit 48, and the output unit 50. The control unit 80 also controls the operation of the signal processing unit 60.

  FIG. 4 is a timing chart showing the operation of the photoelectric conversion block 12. In one photoelectric conversion block 12, the drive circuit 70 controls the transfer unit 44 and the charge exclusion unit 48 connected to the photoelectric conversion pixel unit 20 and the reference pixel unit 22 at the same timing. However, with respect to the photoelectric conversion pixel unit 20 and the reference pixel unit 22 provided with filters having the same spectral characteristics, the drive circuit 70 causes the output unit 50 to output pixel signals at different timings.

  For example, the drive circuit 70 turns on each charge exclusion unit 48 (RST) of one photoelectric conversion block 12 at time t2. As a result, the potential of the gate of each amplifier 49 is reset. The drive circuit 70 keeps the transistors of the charge exclusion units 48 (RST) in the on state from time t2 to time t5.

  At time t3, the driving circuit 70 transfers all the photoelectric conversion pixel units 20 and the transfer units 44 (TX_R, TX_G, and B) of the reference pixel units 22 (R pixel unit, G pixel unit, and B pixel unit) in one photoelectric conversion block 12. TX_G) is turned on. Thereby, first, the charges accumulated in each photoelectric conversion pixel unit 20 are eliminated.

  The drive circuit 70 turns off each charge exclusion unit 48 (RST) at time t5. Thereafter, at time t7, the driving circuit 70 transfers all the photoelectric conversion pixel units 20 and the reference pixel units 22 (R pixel unit, G pixel unit, and B pixel unit) of one photoelectric conversion block 12 (TX_R, TX_G and TX_G) are turned on again. As a result, the charges accumulated in all the photoelectric conversion units 42 (R pixel unit, G pixel unit, and B pixel unit) in one photoelectric conversion block 12 correspond to the charge-voltage conversion units 46-1, 46-2, respectively. And 46-3, respectively.

  In a period from time t3 to time t7, all the photoelectric conversion pixel units 20 (R pixel unit, G pixel unit, and B pixel unit) in one photoelectric conversion block 12 accumulate electric charges. That is, the period from time t3 to time t7 is the charge accumulation period of each photoelectric conversion pixel unit 20.

  The drive circuit 70 sequentially turns on the transfer units of the photoelectric conversion pixel units 20 and the reference pixel unit 22 after time t8. In this example, at time t8, one photoelectric conversion unit 42-1 (R1 pixel unit), one photoelectric conversion unit 42-2 (G1 pixel unit), and one photoelectric conversion unit 42- in one photoelectric conversion block 12 are used. 3 (B1 pixel portion) is transferred to signal lines 54-1, 54-2 and 54-3, respectively.

  At time t9, another photoelectric conversion unit 42-1 (R2 pixel unit), another photoelectric conversion unit 42-2 (G2 pixel unit), and another photoelectric conversion unit 42-3 ( The charges accumulated in the (B2 pixel portion) are transferred to the signal lines 54-1, 54-2 and 54-3, respectively. The transfer operation is executed for all the photoelectric conversion pixel units 20 and the reference pixel units 22 in one photoelectric conversion block 12. As a result, the pixel signal of each pixel unit included in one photoelectric conversion block 12 is output to the signal line 54.

  FIG. 5 is a diagram illustrating a partial region 14 of the photoelectric conversion block 12 in the second embodiment. The partial area 14 has a plurality of reference pixel portions 22. In the partial region 14, each of the plurality of reference pixel portions 22 is disposed at a random position. In the partial area 14, the reference pixel unit 22 having a red filter has a reference pixel unit 22-1, the reference pixel unit 22 having a green filter has a reference pixel unit 22-2, and the reference pixel unit 22 has a blue filter. Is described as a reference pixel portion 22-3.

  As described above, the partial region 14 is provided in the photoelectric conversion block 12 of the photoelectric conversion region 11 of the image sensor 10. Therefore, as in the partial region 14 of this example, the reference pixel portions 22 are randomly arranged in each of the photoelectric conversion blocks 12.

  It is preferable that the patterns of the plurality of reference pixel portions 22 arranged at random differ between the two photoelectric conversion blocks. That is, the reference pixel unit 22 is randomly arranged in the entire photoelectric conversion region 11 of the image sensor 10. Thereby, the alias signal generated when the arrangement pattern of the reference pixel portion 22 is periodically provided can be suppressed.

  FIG. 6 is a diagram illustrating a partial region 14 of the photoelectric conversion block 12 in the third embodiment. The partial area 14 has a plurality of reference pixel portions. In the partial region 14, the plurality of reference pixel units 22 are arranged along a plurality of lines parallel to the first direction, and the plurality of reference pixel units 22 are parallel to the second direction perpendicular to the first direction. Arranged along multiple lines. In this example, the reference pixel portions 22 are arranged at intervals of 1, 2, 3, 4 pixels, at intervals of 1, 2, 3, 4 pixels, and at intervals of 1, 2, 3, 4 pixels in the first direction, and Also in the second direction, the pixels are arranged every 1, 2, 3, 4 pixels, every 1, 2, 3, 4 pixels, every 1, 2, 3, 4 pixels, and so on.

  Here, the intervals between the plurality of lines parallel to the first direction in which the plurality of reference pixel portions 22 are arranged are not constant, and the intervals between the plurality of lines parallel to the second direction in which the plurality of reference pixel portions 22 are arranged. Is not constant. As described above, the partial region 14 is provided in the photoelectric conversion block 12 of the photoelectric conversion region 11 of the image sensor 10. Therefore, as in the partial region 14 of this example, the reference pixel portion 22 is disposed in each of the photoelectric conversion blocks 12.

  The arrangement pattern in the plurality of reference pixel portions 22 is preferably the same in at least two photoelectric conversion blocks. Furthermore, it is more preferable that the reference pixel portions 22 have the same arrangement pattern in the entire photoelectric conversion region 11 of the image sensor 10. Note that when the reference pixel portion 22 is arranged in a specific pattern, an alias signal is always generated. However, in FIG. 7, since the arrangement pattern of the reference pixel portion 22 is provided in the entire photoelectric conversion region 11, an alias signal generated compared to the case where the same arrangement pattern is provided in the entire photoelectric conversion region 11. The strength of can be suppressed.

  FIG. 7 is a diagram illustrating a partial region 14 of the photoelectric conversion block 12 according to the fourth embodiment. This example is different from FIG. 6 in that a plurality of first reference pixel units 24 and a plurality of second reference pixel units 26 are used instead of the plurality of reference pixel units 22. The area 30 surrounded by a dotted line at the lower left of the partial area 14 will be described later.

  The partial area 14 has a plurality of reference pixel portions 22. However, the plurality of reference pixel units 22 include a photoelectric conversion unit, and a plurality of first reference pixel units 24 that do not read photoelectrically converted charges as a signal and a plurality of second reference pixels that do not include the photoelectric conversion unit. And a reference pixel portion 26.

  In this example, the plurality of first reference pixel units 24 and the plurality of second reference pixel units 26 are alternately arranged in the first direction. Also in the second direction perpendicular to the first direction, the plurality of first reference pixel units 24 and the plurality of second reference pixel units 26 are alternately arranged. Note that the plurality of first reference pixel units 24 and the plurality of second reference pixel units 26 may be arranged at random.

  As described above, the partial region 14 is provided in the photoelectric conversion block 12 of the photoelectric conversion region 11 of the image sensor 10. Therefore, as in the partial region 14 of this example, the first reference pixel unit 24 and the second reference pixel unit 26 are arranged in each of the photoelectric conversion blocks 12.

  FIG. 8A is an enlarged view of the region 30. The region 30 includes a first reference pixel unit 24-1 having a red filter, a first reference pixel unit 24-2 having a green filter, a second reference pixel unit 26-1 having a red filter, and And a photoelectric conversion pixel portion 20-2.

  The image sensor 10 is passed through the first reference pixel unit 24-1, the photoelectric conversion pixel 20-2, the second reference pixel unit 26-1, and the first reference pixel unit 24-2 in parallel with the second direction. The cutting position is indicated by BB.

  FIG. 8B is a schematic diagram showing the first reference pixel portion 24 and the second reference pixel portion 26 in the BB cross section. The first reference pixel units 24-1 and 24-2 and the second reference pixel unit 26-1 are specific examples of the reference pixel unit 22. The photoelectric conversion pixel unit 20-2 is a so-called normal pixel unit used for outputting a photoelectrically converted pixel signal.

  In the first reference pixel unit 24-1, the output of the photoelectric conversion unit 42-1 is connected to the input of the photoelectric conversion unit 42-1. Also in the first reference pixel unit 24-2, the output of the photoelectric conversion unit 42-2 is connected to the input of the photoelectric conversion unit 42-1. The transfer unit 44, the charge-voltage conversion unit 46, the charge exclusion unit 48, the amplification unit 49, and the output unit illustrated in FIG. 3 except that the ground between the photoelectric conversion unit 42 and the transfer unit 44 is short-circuited. 50, the high potential portion 52, and the signal line 54 are provided in the same manner as in the example of FIG.

  Therefore, the electric charge resulting from the photoelectric conversion is basically not accumulated in the photoelectric conversion unit 42. Even if it is accumulated in the photoelectric conversion unit 42, the charge is not read out as a pixel signal. Charges resulting from the dark current are accumulated in the charge-voltage converter 46. Therefore, dark current can be corrected using the first reference pixel unit 24.

  The second reference pixel unit 26-1 does not have the photoelectric conversion unit 42. That is, one end of the transfer unit 44 is set to the ground potential. Therefore, the dark current can be corrected using the second reference pixel unit 26 in the same manner as the first reference pixel unit 24.

  Since the first reference pixel unit 24 and the second reference pixel unit 26 as the reference pixel unit 22 are provided in the photoelectric conversion region 11, it is possible to detect a dark current without a light shielding layer. Since the light shielding layer is not provided in the photoelectric conversion region 11, the flatness of the photoelectric conversion region 11 can be improved.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described using “first,” “next,” etc. for the sake of convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Image sensor, 11 Photoelectric conversion area | region, 12 Photoelectric conversion block, 14 Partial area | region, 20 Photoelectric conversion pixel part, 22 Reference pixel part, 24 1st reference pixel part, 26 2nd reference pixel part, 30 area | region, 40 Color filter, 42 photoelectric conversion unit, 44 transfer unit, 46 charge voltage conversion unit, 48 charge exclusion unit, 49 amplification unit, 50 output unit, 52 high potential unit, 54 signal line, 60 signal processing unit, 70 drive circuit, 80 control unit, 90 light-shielding layer, 200 imaging device unit, 340 shutter unit, 410 optical axis, 400 single-lens reflex camera, 500 lens unit, 550 lens mount, 600 camera body, 620 body substrate, 622 CPU, 624 image processing ASIC, 634 rear display unit , 650 finder, 652 focus plate, 654 penta prism, 656 Viewfinder optical system, 660 Body mount, 670 Mirror box, 672 Main mirror, 674 Sub mirror, 680 Focusing optical system, 682 Focus detection sensor

Claims (1)

A first pixel that generates an image by performing an imaging operation under a first imaging condition;
A second pixel that performs an imaging operation under the first imaging condition and generates second data used to remove noise included in the first data;
A third pixel for generating third data by performing an imaging operation under a second imaging condition different from the first imaging condition;
A fourth pixel that performs an imaging operation under the second imaging condition and generates fourth data used to remove noise included in the third data;
An imaging device comprising: