JP7797785B2 - Image pickup element and image pickup device - Google Patents

Description

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

Image sensors capable of acquiring signals used for focus detection using the phase difference detection method are known (see, for example, Patent Document 1). There has long been a demand for improved focus detection accuracy.

Japanese Patent Application Laid-Open No. 2017-34606

According to a first aspect, an imaging element includes a microlens onto which light is incident, a first photoelectric conversion unit that converts the light that has passed through the microlens into electric charges, the first photoelectric conversion unit having a first light-receiving area, a second photoelectric conversion unit that converts the light that has passed through the microlens into electric charges, the second photoelectric conversion unit having a second light-receiving area larger than the first light-receiving area, a third photoelectric conversion unit that converts the light that has passed through the microlens into electric charges, the third photoelectric conversion unit having a third light-receiving area larger than the first light-receiving area, a first accumulation unit to which the electric charges converted by the first photoelectric conversion unit are transferred, and a second accumulation unit that transfers the electric charges converted by the second photoelectric conversion unit and the electric charges converted by the third photoelectric conversion unit. the second photoelectric conversion unit is disposed at a position farther from the optical axis of the microlens than the first photoelectric conversion unit, and the third photoelectric conversion unit is disposed at a position farther from the optical axis of the microlens than the first photoelectric conversion unit .
According to a second aspect, an imaging device includes the imaging element according to the first aspect.

1 is a diagram illustrating an example of the configuration of an imaging device according to an embodiment; FIG. 2 is a diagram illustrating a configuration example of an imaging element according to an embodiment. 2 is a diagram illustrating an example of the configuration of a pixel of an imaging element according to an embodiment; 1 is a circuit diagram showing an example of the configuration of a pixel of an imaging element according to an embodiment; 10 is a timing chart for explaining an example of a first readout process by the imaging element according to the embodiment. 10 is a timing chart for explaining an example of a second readout process by the imaging element according to the embodiment. 10 is a timing chart for explaining another example of the second readout process by the imaging element according to the embodiment. FIG. 10 is a diagram illustrating an example of the configuration of a pixel of an image sensor according to Modification 1. 10 is a timing chart for explaining an example of a second readout process by the image sensor according to the first modification. FIG. 10 is a diagram illustrating an example of the configuration of a pixel of an image sensor according to Modification 2. FIG. 11 is a diagram illustrating an example of the configuration of a pixel of an imaging element according to Modification 3. FIG. 10 is a diagram for explaining an example of the configuration of a pixel of an imaging element according to Modification 4.

(Embodiment)
1 is a diagram showing an example of the configuration of a camera 1, which is an example of an imaging device according to an embodiment. The camera 1 has a camera body 2 and a lens unit 3, which is an accessory that can be attached to the camera body 2. The lens unit 3 is an interchangeable lens. Note that the camera 1 may also be a camera in which the camera body 2 and the lens unit 3 are integrally configured.

The lens unit (interchangeable lens) 3 is detachably attached to the camera body 2 by a mount unit (not shown). When the interchangeable lens 3 is attached to the camera body 2, multiple terminals on the body-side connection unit 202 and multiple terminals on the lens-side connection unit 302 are electrically connected. This enables power to be supplied from the camera body 2 to the interchangeable lens 3 and communication between the camera body 2 and the interchangeable lens 3.

Light from the subject is incident in the positive direction of the Z axis in Figure 1. As shown by the coordinate axes in Figure 1, the direction towards the front of the paper, perpendicular to the Z axis, is the positive X axis, and the direction downward on the paper, perpendicular to the Z and X axes, is the positive Y axis. In other figures, the coordinate axes may be displayed based on the coordinate axes in Figure 1 to indicate the orientation of each figure.

The interchangeable lens 3 includes an optical system 31, a lens control unit 32, and a lens memory 33. The optical system 31 is a photographic optical system (imaging optical system) 31 that has multiple lenses, including a focus lens (focus adjustment lens), and an aperture (aperture stop), and forms an image of a subject on the image sensor 21 of the camera body 2.

The lens control unit 32 has a processor and memory, and controls each part of the interchangeable lens 3. The lens control unit 32 has devices such as a CPU, FPGA, and ASIC, and memories such as ROM and RAM. The lens control unit 32 reads and executes programs stored in the memory. The lens control unit 32 can also be considered a processing unit (information processing unit) that processes information based on the programs.

When a signal regarding the direction and amount of movement of the focus lens is input from the body control unit 25 of the camera body 2, the lens control unit 32 moves the focus lens forward or backward along the optical axis OA1 based on that signal to adjust the focal position of the photographic optical system 31. The lens control unit 32 also controls the aperture diameter of the diaphragm based on the signal output from the body control unit 25.

The lens memory 33 is composed of a non-volatile storage medium, etc. Information related to the interchangeable lens 3 is stored (recorded) in the lens memory 33. The lens memory 33 stores data related to the infinity position and close position of the focus lens, data related to the shortest focal length and longest focal length of the interchangeable lens 3, data related to the aperture value (F-number), etc. The lens control unit 32 writes data to the lens memory 33 and reads data from the lens memory 33.

Next, an example configuration of the camera body 2 will be described. The camera body 2 comprises an image sensor 21, a memory 22, a display unit 23, an operation unit 24, and a body control unit 25. The image sensor 21 is an image sensor such as a CMOS image sensor or a CCD image sensor. The image sensor 21 receives a light beam that has passed through the photographic optical system 31 and captures a subject image formed by the photographic optical system 31. The image sensor 21 has multiple pixels, each with a photoelectric conversion unit, arranged two-dimensionally (in the row and column directions). The photoelectric conversion unit is composed of a photodiode (PD) and converts incident light into an electric charge. The image sensor 21 photoelectrically converts the received light to generate a signal and outputs the generated signal to the body control unit 25.

The memory 22 is composed of a non-volatile storage medium, etc. The memory 22 stores image data, programs and data used to control each part of the camera 1, etc. The body control unit 25 writes data to the memory 22 and reads data from the memory 22.

The display unit 23 is a liquid crystal display, an organic EL display, or the like. The display unit 23 displays a through image (live view image) of the subject, an image based on image data stored in the memory 22, an image showing a focus detection area (AF area) such as an AF frame, information related to shooting such as shutter speed and aperture value, and a menu screen, etc. The display unit 23 may include a touch panel and may also function as an input/output unit. The display unit (input/output unit) 23 may generate a signal based on operations by the user and output it to the body control unit 25.

The operation unit 24 includes components such as a release button, a power button (switch), operation buttons, and switches for switching between various modes, and accepts operations on the camera 1. The operation unit 24 detects operations by the user and outputs signals based on the operations to the body control unit 25. The operation unit 24 may also include a touch panel on the display unit 23.

The body control unit 25 has a processor and memory, and controls each part of the camera 1. The body control unit 25 has devices such as a CPU, GPU, FPGA, and ASIC, and memory such as ROM and RAM. The body control unit 25 reads and executes programs stored in the memory. The body control unit 25 can also be considered a processing unit (information processing unit) that processes information based on the programs. The body control unit 25 has an imaging control unit 25a, an image processing unit 25b, and a focus detection unit 25c.

The imaging control unit 25a supplies signals that control the imaging element 21 to the imaging element 21, and controls the operation of the imaging element 21. The body control unit 25 causes the imaging element 21 to capture a subject image and output pixel signals when taking still images, taking video, displaying a through image on the display unit 23, etc. The pixels of the imaging element 21 can output signals used for image generation (imaging signals) and signals used for focus detection (focus detection signals).

The image processing unit 25b performs various image processing on the image pickup signals of each pixel output from the image sensor 21 to generate image data (still image data, moving image data) including the signals of each pixel. The image processing unit 25b performs image processing such as color interpolation and gradation conversion. The image processing unit 25b is an image data generation unit that generates image data. Note that the image processing unit 25b may also generate image data using focus detection signals of the pixels.

The focus detection unit 25c performs focus detection processing required for automatic focusing (AF) of the photographing optical system 31. The focus detection unit 25c calculates the amount of defocus using a phase difference detection method, using the focus detection signals of each pixel output from the image sensor 21. The focus detection unit 25c calculates the amount of image shift by performing a correlation operation between a focus detection signal generated by capturing an image formed by a light beam that has passed through a portion of the exit pupil of the photographing optical system 31 and a focus detection signal generated by capturing an image formed by a light beam that has passed through another portion of the exit pupil. The focus detection unit 25c converts this amount of image shift into a defocus amount using a predetermined conversion formula.

The focus detection unit 25c calculates the amount of movement of the focus lens to the in-focus position based on the calculated defocus amount. The focus lens is moved according to the amount of movement, and focus adjustment is performed. In this way, the focus detection unit 25c controls the position of the focus lens so that the image of the subject captured by the photographing optical system 31 is focused (formed) on the image sensor 21.

Figure 2 is a diagram showing an example configuration of an image sensor according to an embodiment. The image sensor 21 has a pixel section (pixel region) 100 in which pixels are arranged two-dimensionally (in row directions (±X directions) and column directions (±Y directions)), a supply unit 60, a readout control unit 70, and multiple processing units 80. In Figure 2, the pixel in the upper left corner is pixel 10 (1,1) in the first row and first column, and the pixel in the lower right corner is pixel 10 (10,6) in the tenth row and sixth column, showing a total of 60 pixels in 10 rows and 6 columns. Note that the number and arrangement of pixels arranged in the image sensor 21 are not limited to the example shown.

In the image sensor 21, a vertical signal line 55 is provided for each of the multiple pixels 10 arranged in the horizontal direction (row direction). It can also be said that a vertical signal line 55 is provided for each pixel column, which is a row of multiple pixels arranged in the vertical direction (column direction). A current source 56 and a processing unit 80 are provided for each of the multiple vertical signal lines 55.

The supply unit 60 is controlled by the imaging control unit 25a of the camera 1 and supplies a predetermined voltage (potential) to each pixel. The supply unit 60 supplies the power supply voltage VDD to the pixels 10 via the supply units 65 and 66, which will be described later.

The readout control unit 70 is composed of multiple circuits, including a timing generator, logic circuits (AND circuits, OR circuits, etc.), latch circuits, and buffers. The readout control unit 70 is controlled by the imaging control unit 25a and supplies signals such as signal TX, signal RST, signal SEL, and signal FD_SW (described below) to each pixel to control the operation of each pixel. The readout control unit 70 supplies signals to the gates of each transistor in the pixel to turn the transistor on (connected, conductive, short-circuited) or off (disconnected, non-conductive, open, blocked). The signal from each pixel is output to the vertical signal line 55 connected to that pixel.

The current source 56 is connected to each pixel 10 via the vertical signal line 55. The current source 56 generates a current for reading out a signal from the pixel 10 and supplies the generated current to the vertical signal line 55 and each pixel 10.

The processing unit 80 is configured to include an analog/digital conversion unit (AD conversion unit). The processing unit 80 converts analog pixel signals input from each pixel 10 via the vertical signal lines 55 into digital signals. The processing unit 80 may also have an amplifier unit that amplifies the pixel signals input via the vertical signal lines 55 by a predetermined gain (amplification factor). In this case, the processing unit 80 may convert the pixel signals amplified by the amplifier unit into digital signals.

The processing unit 80 outputs the pixel signals converted into digital signals to a signal processing unit (not shown). The signal processing unit performs signal processing such as correlated double sampling and signal amount correction on the input pixel signals, and then outputs the processed signals to the body control unit 25. Note that signal processing such as correlated double sampling on pixel signals may also be performed by the processing unit 80. In this case, the processing unit 80 may perform signal processing such as correlated double sampling on the pixel signals converted into digital signals, and then output the processed signals to the body control unit 25.

Figure 3 is a diagram showing an example of the configuration of a pixel of an image sensor according to an embodiment. Pixel 10 of image sensor 21 has a microlens 51, a color filter 52, a light-shielding portion 53, a first photoelectric conversion portion (PD) 11, and a second photoelectric conversion portion (PD) 41. Microlens 51 focuses light incident from above via the imaging optical system 31 in Figure 3(a). Light-shielding portion 53 is provided at the boundary between pixels and prevents light from leaking into surrounding areas, thereby preventing noise from being mixed into the pixel signal.

Any of three color filters 52 with different spectral sensitivities, for example, R (red), G (green), or B (blue), is disposed in each pixel 10. The R color filter 52 transmits light in a first wavelength range (red (R) light), the G color filter 52 transmits light in a second wavelength range (green (G) light), and the B color filter 52 transmits light in a third wavelength range (blue (B) light). The image sensor 21 has pixels with R color filters 52 (R pixels), pixels with G color filters 52 (G pixels), and pixels with B color filters 52 (B pixels).

The image sensor 21 may be provided with pixels 10 equipped with filters having spectral characteristics that separate light into the first, second, and third wavelength ranges. Some of the pixels 10 provided in the image sensor 21 may not require the color filter 52. Alternatively, complementary color filters (CMY) may be provided.

The first photoelectric conversion unit 11 can generate charges used for image generation. The first photoelectric conversion unit 11 (PD) is formed in the central region of the pixel 10 and is located on the optical axis OA2 of the microlens 51 in the example shown in FIG. 3. The first photoelectric conversion unit 11 receives a light beam that has passed through the exit pupil of the imaging optical system 31 and performs photoelectric conversion to generate charges. The pixel 10 can output a signal based on the charges generated by the first photoelectric conversion unit 11, i.e., a signal based on the charges accumulated by photoelectrically converting the light beam that has passed through the exit pupil of the imaging optical system 31, as a signal used for image generation (image capture signal). It can also be said that the first photoelectric conversion unit 11 generates charges used for generating signals for images.

The second photoelectric conversion unit 41 can generate electric charges used for focus detection. Multiple second photoelectric conversion units 41 are provided around the first photoelectric conversion unit 11. As shown in Figures 3(a) and (b), the multiple second photoelectric conversion units 41 are provided so as to sandwich the first photoelectric conversion unit 11. The multiple second photoelectric conversion units 41 are arranged so that light that has passed through different regions of the exit pupil of the imaging optical system 31 is incident on them. In the example shown in Figure 3, the pixel 10 has four second photoelectric conversion units 41 (41a to 41d).

As shown in FIG. 3(b), the second photoelectric conversion unit 41a (PD1L) is located in the upper left position, the second photoelectric conversion unit 41b (PD1R) is located in the upper right position, the second photoelectric conversion unit 41c (PD2L) is located in the lower left position, and the second photoelectric conversion unit 41d (PD2R) is located in the lower right position. The area of each of the second photoelectric conversion units 41a to 41d is larger than the area of the first photoelectric conversion unit 11. The second photoelectric conversion units 41a to 41d efficiently receive light that has passed through different regions of the pupil of the imaging optical system 31, allowing for appropriate pupil division.

The second photoelectric conversion unit 41 receives light beams that have passed through a partial area of the exit pupil of the imaging optical system 31 and performs photoelectric conversion to generate electric charges. The pixel 10 can output a signal based on the electric charges generated by the second photoelectric conversion unit 41, i.e., a signal based on the electric charges accumulated by photoelectrically converting the light beams that have passed through a partial area of the exit pupil, as a signal used for focus detection (focus detection signal). It can also be said that the second photoelectric conversion unit 41 generates electric charges used to generate signals for focus detection. The focus detection unit 25c of the body control unit 25 can detect the amount of defocus using multiple focus detection signals based on the electric charges generated by the multiple second photoelectric conversion units 41.

Figure 4 is a circuit diagram showing an example configuration of a pixel of an image sensor according to an embodiment. Pixel 10 has a first photoelectric conversion unit 11, a first transfer unit 12, a first accumulation unit 14, a first discharge unit 15, an amplifier unit 16, a selection unit 17, and a second discharge unit 18. Pixel 10 also has a second photoelectric conversion unit 41 (41a to 41d), a second transfer unit 42 (42a to 42d), a second accumulation unit 44, and a connection unit 45.

The supply unit 65 is a part (wiring, electrodes, etc.) of the image sensor 21 that supplies (applies) the power supply voltage VDD to the first discharge unit 15 and the amplifier unit 16. The supply unit 66 is a part of the image sensor 21 that supplies the power supply voltage VDD to the second discharge unit 18. The supply units 65 and 66 receive the power supply voltage VDD from the supply unit 60 (see Figure 2). The supply units 65 and 66 may be part of the supply unit 60.

As described above, the pixel 10 includes a first photoelectric conversion unit 11 that generates charges used for image generation, and second photoelectric conversion units 41a-41d that generate charges used for focus detection. The first photoelectric conversion unit 11 and second photoelectric conversion units 41a-41d are each photodiodes PD that convert incident light into charges and store the photoelectrically converted charges.

The first transfer unit 12 is composed of a transistor M1 controlled by a signal TX_C1, and electrically connects or disconnects the first photoelectric conversion unit 11 and the first accumulation unit 14. The first transfer unit 12 transfers the charges photoelectrically converted by the first photoelectric conversion unit 11 to the first accumulation unit 14. The transistor M1 is a transfer transistor.

The first accumulation unit 14 is a floating diffusion (FD). The capacitance C1 of the first accumulation unit 14 is a capacitance that accumulates (holds) the charge transferred to the first accumulation unit 14. The first accumulation unit 14 can accumulate the charge generated by the first photoelectric conversion unit 11 and the second photoelectric conversion units 41a to 41d.

The amplifier unit 16 is composed of a transistor M3, whose gate (terminal) is connected to the first accumulation unit 14. The amplifier unit 16 amplifies and outputs signals based on the charges transferred from the first photoelectric conversion unit 11 and the second photoelectric conversion units 41a to 41d. The drain (terminal) and source (terminal) of the transistor M3 are connected to a supply unit 65, which supplies the power supply voltage VDD, and a selection unit 17, respectively. The source of the amplifier unit 16 is connected to the vertical signal line 55 via the selection unit 17. The transistor M3 is an amplifying transistor. The amplifier unit 16 and selection unit 17 together constitute an output unit that generates and outputs a signal based on the charges generated by the photoelectric conversion unit.

The first drain unit 15 is composed of a transistor M2 controlled by a signal RST. The first drain unit 15 is a connection unit 15 that electrically connects or disconnects the supply unit 65 and the first storage unit 14. The first drain unit 15 connects the supply unit 65 and the first storage unit 14, thereby discharging the charge accumulated by the first storage unit 14 to the supply unit 65. The first drain unit 15 can also discharge the charge accumulated by the second storage unit 44 to the supply unit 65 via the connection unit 45. The first drain unit (reset unit) 15 discharges the charge accumulated in the first storage unit 14 and the second storage unit 44, and resets the voltages of the first storage unit 14 and the second storage unit 44. Transistor M2 is a reset transistor.

The selection unit 17 is composed of a transistor M4 controlled by a signal SEL, and electrically connects or disconnects the amplifier unit 16 and the vertical signal line 55. When transistor M4 of the selection unit 17 is in the on state, it outputs a signal from the amplifier unit 16 to the vertical signal line 55. Transistor M4 is a selection transistor.

The second discharge unit 18 is composed of a transistor M5 controlled by a signal TX_C2. The second discharge unit 18 is a connection unit 18 that electrically connects or disconnects the supply unit 66 and the first photoelectric conversion unit 11. The second discharge unit 18 connects the supply unit 66 and the first photoelectric conversion unit 11, thereby discharging the charge accumulated in the first photoelectric conversion unit 11 to the supply unit 66. The second discharge unit (reset unit) 18 discharges the charge accumulated in the first photoelectric conversion unit 11 and resets the voltage of the first photoelectric conversion unit 11. Transistor M5 can also be referred to as a reset transistor.

The second transfer unit 42a is composed of a transistor M6a controlled by a signal TX_1L and electrically connects or disconnects the second photoelectric conversion unit 41a and the second accumulation unit 44. The second transfer unit 42b is composed of a transistor M6b controlled by a signal TX_1R and electrically connects or disconnects the second photoelectric conversion unit 41b and the second accumulation unit 44. The second transfer unit 42c is composed of a transistor M6c controlled by a signal TX_2L and electrically connects or disconnects the second photoelectric conversion unit 41c and the second accumulation unit 44. The second transfer unit 42d is composed of a transistor M6d controlled by a signal TX_2R and electrically connects or disconnects the second photoelectric conversion unit 41d and the second accumulation unit 44.

The second transfer units 42a to 42d transfer the charges photoelectrically converted by the second photoelectric conversion units 41a to 41d, respectively, to the second accumulation unit 44. The transistors M6a to M6d are transfer transistors. The capacitances C2a to C2d of the second accumulation unit 44 accumulate (hold) the charges transferred to the second accumulation unit 44. The second accumulation unit 44 accumulates the charges generated by the second photoelectric conversion units 41a to 41d.

The connection unit 45 is composed of a transistor M7 controlled by a signal FD_SW, and electrically connects or disconnects the first accumulation unit 14 and the second accumulation unit 44. By connecting the first accumulation unit 14 and the second accumulation unit 44, the connection unit 45 makes it possible to transfer the charge in the second accumulation unit 44 to the first accumulation unit 14. Note that the connection unit 45 and the above-mentioned first discharge unit (connection unit) 15 and second discharge unit (connection unit) 18 can each be considered to be switching units (switch units) that switch between connection and disconnection.

The readout control unit 70 (see Figure 2) controls signals TX, SEL, FD_SW, etc. input to each pixel 10 to read out signals based on the charges generated in the first photoelectric conversion unit 11 and signals based on the charges generated in the second photoelectric conversion unit 41. When transistor M7 of the connection unit 45 is turned off, the first accumulation unit 14 and the second accumulation unit 44 are electrically disconnected. In this case, the charges transferred from the first photoelectric conversion unit 11 by the first transfer unit 12 are accumulated in the first accumulation unit 14. The amplification unit 16 and selection unit 17 are able to output a signal (image signal) corresponding to the charges accumulated in the first accumulation unit 14 to the vertical signal line 55.

When transistor M7 of connection unit 45 is turned on, the first accumulation unit 14 and second accumulation unit 44 are electrically connected. In this case, the charge transferred from the second photoelectric conversion unit 41 by the second transfer unit 42 is accumulated in the second accumulation unit 44 and the first accumulation unit 14. The amplification unit 16 and selection unit 17 are able to output a signal (focus detection signal) corresponding to the charge accumulated in the first accumulation unit 14 and second accumulation unit 44 to the vertical signal line 55.

In this way, the image sensor 21 according to this embodiment makes it possible to obtain, for each pixel, an image signal used for image generation and a focus detection signal used for focus detection. Furthermore, in this embodiment, the first accumulation unit 14, first discharge unit 15, amplifier unit 16, and selection unit 17 are provided in common to the first photoelectric conversion unit 11 and multiple second photoelectric conversion units 41 of the pixel 10. Compared to a case where an amplifier unit 16, selection unit 17, etc. are provided separately for the first photoelectric conversion unit 11 and the second photoelectric conversion unit 41, the circuit area for each pixel 10 can be reduced. This prevents an increase in the chip area of the image sensor 21 and an increase in manufacturing costs.

In addition, the imaging control unit 25a according to this embodiment controls the readout control unit 70 to perform a process (first readout process) of individually reading out signals based on the charges generated by each of the multiple second photoelectric conversion units 41 of the imaging element 21, and a process (second readout process) of reading out signals based on the sum of the charges generated by each of the multiple second photoelectric conversion units 41. Below, examples of methods for reading out signals from pixels are described with reference to the drawings.

Figure 5 is a timing chart illustrating an example of a first readout process performed by an image sensor according to an embodiment. Figure 5 shows, on the same time axis, a control signal input to a pixel and a signal output from the pixel and sampled. In Figure 5, a transistor receiving a high-level (e.g., power supply voltage VDD) control signal (signal RST, signal TX, signal SEL, signal FD_SW, etc.) is turned on, and a transistor receiving a low-level (e.g., ground voltage) control signal is turned off.

At time t1 shown in FIG. 5, signal FD_SW goes high. When signal FD_SW goes high, transistor M7 of connection unit 45 turns on, electrically connecting the first accumulation unit 14 and second accumulation unit 44. Also, at time t1, signal TX_C2 goes high. When signal TX_C2 goes high, transistor M5 of second discharge unit 18 in pixel 10 turns on, electrically connecting the first photoelectric conversion unit 11 and supply unit 66. This causes the charge in the first photoelectric conversion unit 11 to be discharged to the supply unit 66, resetting the voltage of the first photoelectric conversion unit 11. This resets the first photoelectric conversion unit 11, preventing the charge in the first photoelectric conversion unit 11 from saturating and leaking into other photoelectric conversion units and accumulation units. This prevents noise from being mixed into the pixel signal.

Also, at time t1, signal RST goes high. When signal RST goes high, transistor M2 of the first discharge unit 15 goes on, electrically connecting the first storage unit 14 and the supply unit 65. Also, the second storage unit 44 is electrically connected to the supply unit 65 via the connection unit 45 and the first storage unit 14. As a result, the charges in the first storage unit 14 and the second storage unit 44 are reset, and the voltages of the first storage unit 14 and the second storage unit 44 become the reset voltage.

Furthermore, at time t1, signal SEL goes high. When signal SEL goes high, transistor M4 of selection unit 17 goes on. As a result, a signal based on the reset voltage of pixel 10, i.e., the signal after the charges in first storage unit 14 and second storage unit 44 of pixel 10 have been reset, is output to vertical signal line 55 by amplifier unit 16 and selection unit 17. The signal based on the reset voltage is input to processing unit 80 via vertical signal line 55 as reset signal (dark signal) Rst1L and sampled. Reset signal Rst1L is converted into a digital signal by processing unit 80.

At time t2, signal TX_1L goes high. When signal TX_1L goes high, transistor M6a of second transfer unit 42a in pixel 10 turns on, electrically connecting second photoelectric conversion unit 41a and second accumulation unit 44. Furthermore, second accumulation unit 44 is electrically connected to first accumulation unit 14 via connection unit 45. Therefore, the charge photoelectrically converted by second photoelectric conversion unit 41a is transferred to second accumulation unit 44 and first accumulation unit 14.

Also, at time t2, because signal SEL is at a high level, a signal based on the charge generated by the second photoelectric conversion unit 41a of pixel 10 is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The signal based on the charge generated by the second photoelectric conversion unit 41a is output as pixel signal Sig1L via the vertical signal line 55 to the processing unit 80 and sampled. The pixel signal Sig1L is converted into a digital signal by the processing unit 80.

At time t3, signal RST goes high, turning on transistor M2 of the first discharge unit 15, resetting the charges in the first storage unit 14 and second storage unit 44, and setting the voltages of the first storage unit 14 and second storage unit 44 to the reset voltage. Because signal SEL is high, a signal based on the reset voltage is output to vertical signal line 55 by amplifier unit 16 and selector unit 17. The signal based on the reset voltage is input to processing unit 80 via vertical signal line 55 as reset signal Rst1R and converted into a digital signal.

At time t4, signal TX_1R goes high, turning on transistor M6b of second transfer unit 42b and electrically connecting second photoelectric conversion unit 41b and second accumulation unit 44. As a result, the charges photoelectrically converted by second photoelectric conversion unit 41b are transferred to second accumulation unit 44 and first accumulation unit 14. Also, because signal SEL is high, a signal based on the charges generated by second photoelectric conversion unit 41b is output to vertical signal line 55 by amplifier unit 16 and selector unit 17. The signal based on the charges generated by second photoelectric conversion unit 41b is input to processing unit 80 as pixel signal Sig1R via vertical signal line 55 and converted into a digital signal.

At time t5, signal RST goes high, turning on transistor M2 of the first discharge unit 15 and causing the voltages of the first storage unit 14 and second storage unit 44 to become the reset voltage. A signal Rst2L based on the reset voltage is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The reset signal Rst2L is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t6, signal TX_2L goes high, turning on transistor M6c of the second transfer unit 42c, and the charges photoelectrically converted by the second photoelectric conversion unit 41c are transferred to the second accumulation unit 44 and the first accumulation unit 14. A signal Sig2L based on the charges generated by the second photoelectric conversion unit 41c is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The pixel signal Sig2L is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t7, signal RST goes high, causing the voltages of the first storage unit 14 and second storage unit 44 to become reset voltages. A signal Rst2R based on the reset voltage is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The reset signal Rst2R is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t8, signal TX_2R goes high, turning on transistor M6d of second transfer unit 42d, and the charges photoelectrically converted by second photoelectric conversion unit 41d are transferred to second accumulation unit 44 and first accumulation unit 14. A signal Sig2R based on the charges generated by second photoelectric conversion unit 41d is output to vertical signal line 55 by amplifier unit 16 and selector unit 17. Pixel signal Sig2R is input to processing unit 80 via vertical signal line 55 and converted into a digital signal.

At time t9, signal FD_SW goes low, turning off transistor M7 of connection unit 45. Also at time t9, signal TX_C2 goes low, turning off transistor M5 of second discharge unit 18. Furthermore, signal SEL goes low, turning off transistor M4 of selection unit 17.

At time t10, signal RST goes high, and the voltage of the first accumulation unit 14 becomes the reset voltage. Also at time t10, signal SEL goes high. When signal SEL goes high, a signal based on the reset voltage is output to the vertical signal line 55 by the amplifier unit 16 and the selector unit 17. The signal based on the reset voltage is input to the processing unit 80 as reset signal RstC via the vertical signal line 55 and converted into a digital signal.

At time t11, signal TX_C1 goes high, turning on transistor M1 of the first transfer unit 12 and transferring the charges photoelectrically converted by the first photoelectric conversion unit 11 to the first accumulation unit 14. Because signal SEL is high, a signal based on the charges generated by the first photoelectric conversion unit 11 is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The signal based on the charges generated by the first photoelectric conversion unit 11 is input to the processing unit 80 as pixel signal SigC via the vertical signal line 55 and converted into a digital signal.

The processing unit 80 performs correlated double sampling (CDS) using the reset signal and pixel signals converted into digital signals. The processing unit 80 performs CDS processing, such as differential processing between signals Rst1L and Sig1L, differential processing between signals Rst1R and Sig1R, differential processing between signals Rst2L and Sig2L, differential processing between signals Rst2R and Sig2R, and differential processing between signals RstC and SigC. After performing signal processing such as CDS processing, the processing unit 80 outputs the processed signals to the body control unit 25 as an imaging signal and a focus detection signal.

In this way, the readout control unit 70 of the image sensor 21 controls the connection unit 45 to read out the image signal (signal SigC) used for image generation and the focus detection signals (signals Sig1L, Sig1R, Sig2L, Sig2R) used for focus detection. It is possible to obtain an image signal and a focus detection signal for each pixel 10.

Figure 6 is a timing chart illustrating an example of a second readout process performed by an image sensor according to an embodiment. At time t21 shown in Figure 6, signal FD_SW goes high, turning on transistor M7 of connection unit 45 and electrically connecting the first accumulation unit 14 and second accumulation unit 44. Furthermore, signal TX_C2 goes high, turning on transistor M5 of second discharge unit 18 and electrically connecting the first photoelectric conversion unit 11 and supply unit 66.

Also, at time t21, signal RST goes high, turning on transistor M2 of the first discharge unit 15, resetting the charges in the first storage unit 14 and the second storage unit 44, and setting the voltages of the first storage unit 14 and the second storage unit 44 to the reset voltage. Also, signal SEL goes high, causing a signal Rst based on the reset voltage to be output to the vertical signal line 55 by the amplifier unit 16 and the selector unit 17. The reset signal Rst is input to the processing unit 80 via the vertical signal line 55 and sampled. The reset signal Rst is converted into a digital signal by the processing unit 80.

At time t22, signal TX_1L goes high, turning on transistor M6a of the second transfer unit 42a and electrically connecting the second photoelectric conversion unit 41a and the second accumulation unit 44. As a result, the charges photoelectrically converted by the second photoelectric conversion unit 41a are transferred to the second accumulation unit 44 and the first accumulation unit 14. Also, because signal SEL is high, signal Sig1L based on the charges generated by the second photoelectric conversion unit 41a is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The pixel signal Sig1L is input to the processing unit 80 via the vertical signal line 55, sampled, and converted into a digital signal.

At time t23, signal TX_1R goes high, turning on transistor M6b of second transfer unit 42b and electrically connecting second photoelectric conversion unit 41b and second accumulation unit 44. Charges photoelectrically converted by second photoelectric conversion unit 41b are transferred to second accumulation unit 44 and first accumulation unit 14. In this case, the charges transferred from second photoelectric conversion unit 41a and accumulated in second accumulation unit 44 and first accumulation unit 14 are added (summed) with the charges transferred from second photoelectric conversion unit 41b. This also means that the charges generated by second photoelectric conversion unit 41a and second photoelectric conversion unit 41b are mixed.

Also, at time t23, because the signal SEL is at a high level, the signal Sig1L+1R, which is based on the charges generated by the second photoelectric conversion unit 41a and the second photoelectric conversion unit 41b, is output to the vertical signal line 55 by the amplifier unit 16 and the selector unit 17. The pixel signal Sig1L+1R is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t24, signal TX_2L goes high, turning on transistor M6c of the second transfer unit 42c and electrically connecting the second photoelectric conversion unit 41c and the second accumulation unit 44. The charges photoelectrically converted by the second photoelectric conversion unit 41c are transferred to the second accumulation unit 44 and the first accumulation unit 14. As a result, the charges generated by each of the second photoelectric conversion units 41a to 41c are added in the second accumulation unit 44 and the first accumulation unit 14. Because signal SEL is high, signal Sig1L+1R+2L, based on the charges generated by the second photoelectric conversion units 41a to 41c, is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The pixel signal Sig1L+1R+2L is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t25, signal TX_2R goes high, turning on transistor M6d of the second transfer unit 42d and electrically connecting the second photoelectric conversion unit 41d and the second accumulation unit 44. The charges generated in each of the second photoelectric conversion units 41a to 41d are added in the second accumulation unit 44 and the first accumulation unit 14. Because signal SEL is high, signal Sig1L+1R+2L+2R, based on the charges generated in the second photoelectric conversion units 41a to 41d, is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The pixel signal Sig1L+1R+2L+2R is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal. At time t26, signals FD_SW, TX_C2, and SEL are all set low.

At time t27, signal RST goes high, causing the voltage of the first accumulation unit 14 to become the reset voltage. Furthermore, signal SEL goes high, causing a signal RstC based on the reset voltage to be output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The reset signal RstC is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal. At time t28, signal TX_C1 goes high, turning on transistor M1 of the first transfer unit 12 and transferring the charges photoelectrically converted by the first photoelectric conversion unit 11 to the first accumulation unit 14. A signal SigC based on the charges generated by the first photoelectric conversion unit 11 is output to the vertical signal line 55 by the amplifier unit 16 and selector unit 17. The pixel signal SigC is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

The processing unit 80 performs signal processing such as CDS processing using the reset signal converted to a digital signal and the pixel signal, and then outputs the processed signal to the body control unit 25. Note that the signals Sig1R, Sig2L, and Sig2R can be obtained by performing subtraction processing between the pixel signals (Sig1L, Sig1L+1R, Sig1L+1R+2L, and Sig1L+1R+2L+2R).

Figure 7 is a timing chart illustrating another example of the second readout process performed by the image sensor according to the embodiment. At time t31 shown in Figure 7, the signal FD_SW goes high, electrically connecting the first storage unit 14 and the second storage unit 44. Furthermore, the signal TX_C2 goes high, electrically connecting the first photoelectric conversion unit 11 and the supply unit 66.

Also, at time t31, signal RST goes high, and the voltages of the first storage unit 14 and second storage unit 44 become the reset voltage. When signal SEL goes high, signal RstL based on the reset voltage is output to vertical signal line 55 by amplifier unit 16 and selector unit 17. Signal RstL is input to processing unit 80 via vertical signal line 55, sampled, and converted into a digital signal.

At time t32, signals TX_1L and TX_2L each go high, electrically connecting the second photoelectric conversion unit 41a, the second photoelectric conversion unit 41c, and the second accumulation unit 44. In the second accumulation unit 44 and the first accumulation unit 14, the charges transferred from the second photoelectric conversion unit 41a and the second photoelectric conversion unit 41c are added together. Because signal SEL is high, signal Sig1L+2L, based on the charges generated in the second photoelectric conversion unit 41a and the second photoelectric conversion unit 41c, is output to the vertical signal line 55. Signal Sig1L+2L is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t33, signal RST goes high, and the voltages of the first storage unit 14 and second storage unit 44 become reset voltages. A signal RstR based on the reset voltage is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

At time t34, signals TX_1R and TX_2R each go high, electrically connecting the second photoelectric conversion unit 41b, the second photoelectric conversion unit 41d, and the second accumulation unit 44. In the second accumulation unit 44 and the first accumulation unit 14, the charges transferred from the second photoelectric conversion unit 41b and the second photoelectric conversion unit 41d are added together. Because signal SEL is high, signal Sig1R+2R, based on the charges generated in the second photoelectric conversion unit 41b and the second photoelectric conversion unit 41d, is output to the vertical signal line 55. Signal Sig1R+2R is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal. At time t35, signals FD_SW, TX_C2, and SEL each go low.

During the period from time t36 to time t38 shown in Figure 7, the reset signal RstC and pixel signal SigC are read out and converted into digital signals, similar to the period from time t27 to time t29 shown in Figure 6.

In the above example, the signal Sig1L+2L based on the charges generated by the second photoelectric conversion units 41a and 41c and the signal Sig1R+2R based on the charges generated by the second photoelectric conversion units 41b and 41d are read out. However, it is also possible to read out the signal Sig1L+1R based on the charges generated by the second photoelectric conversion units 41a and 41b and the signal Sig2L+2R based on the charges generated by the second photoelectric conversion units 41c and 41d.

As explained using Figures 6 and 7, the readout control unit 70 of the image sensor 21 can perform a second readout process to read out a signal generated by adding together the charges generated by multiple second photoelectric conversion units 41. In the case of the second readout process, the time required to read out pixel signals can be shortened compared to the first readout process of Figure 5. This makes it possible to read out focus detection signals at high speed.

According to the above-described embodiment, the following effects can be obtained.
(1) The image sensor 21 includes a first photoelectric conversion unit (first photoelectric conversion unit 11) that photoelectrically converts light transmitted through the microlens 51 to generate electric charges, a second photoelectric conversion unit and a third photoelectric conversion unit (e.g., second photoelectric conversion units 41a and 41b) that photoelectrically convert light transmitted through the microlens 51 to generate electric charges, a first accumulation unit (first accumulation unit 14) that accumulates the electric charges generated by the first photoelectric conversion unit, and a third accumulation unit (first accumulation unit 15) that transfers the electric charges generated by the first photoelectric conversion unit to the first accumulation unit. The image pickup device includes a first transfer unit (first transfer unit 12), a second accumulation unit (second accumulation unit 44) that accumulates at least one of the charges generated by the second photoelectric conversion unit and the third photoelectric conversion unit, a second transfer unit (second transfer unit 42 a) that transfers the charges generated by the second photoelectric conversion unit to the second accumulation unit, a third transfer unit (second transfer unit 42 b) that transfers the charges generated by the third photoelectric conversion unit to the second accumulation unit, and a connection unit (connection unit 45) that can connect the first accumulation unit and the second accumulation unit. In this embodiment, the plurality of second photoelectric conversion units 41 and the second transfer unit 42 are electrically connected to the first accumulation unit 14 (FD) via the connection unit 45. The charges photoelectrically converted by the second photoelectric conversion unit 41 can be transferred to the FD 14, and a focus detection signal can be read out.

(2) In this embodiment, by controlling the connection unit 45, it is possible to read out an image pickup signal and a focus detection signal from each pixel 10. In this embodiment, the number of elements per pixel 10 can be reduced compared to when circuits are provided for reading out signals separately from the first photoelectric conversion unit 11 and the second photoelectric conversion unit 41. This makes it possible to prevent an increase in chip area.

The following modifications are also within the scope of the present invention, and one or more of these modifications may be combined with the above-described embodiment.

(Variation 1)
8 is a diagram showing an example of the configuration of a pixel of an image sensor according to Modification 1. The pixel 10 according to this modification has a third discharge unit 46 (46a to 46d). The supply unit 67 is a unit that supplies the power supply voltage VDD to the third discharge unit 46, and is provided with the power supply voltage VDD from the supply unit 60. Note that the supply unit 67 may be part of the supply unit 60.

As shown in FIG. 8, the third discharge units 46a-46d are composed of transistors M8a-M8d controlled by signals TX_1L_2-TX_2R_2. The third discharge units 46a-46d are connection units 46a-46d that electrically connect or disconnect the second photoelectric conversion units 41a-41d to the supply unit 67. The third discharge unit (connection unit) 46 can also be considered a switching unit (switch unit) that switches between connection and disconnection. The third discharge unit 46 connects the supply unit 67 to the second photoelectric conversion unit 41, thereby discharging the charge accumulated in the second photoelectric conversion unit 41 to the supply unit 67. The third discharge unit (reset unit) 46 discharges the charge accumulated in the second photoelectric conversion unit 41 and resets the voltage of the second photoelectric conversion unit 41. The transistor M8 can also be considered a reset transistor. The following explanation will mainly focus on operations that differ from those in the above-described embodiment.

Figure 9 is a timing chart illustrating an example of the second readout process by the image sensor according to Variation 1. In the example shown in Figure 9, during the period from time t41 to time t43, when the reset signal RstL and pixel signal Sig1L+2L are read out, signals TX_1R_2 and TX_2R_2 are both high. When signal TX_1R_2 is high, transistor M8b of the third discharge unit 46b is turned on, electrically connecting the second photoelectric conversion unit 41b and the supply unit 67. When signal TX_2R_2 is high, transistor M8d of the third discharge unit 46d is turned on, electrically connecting the second photoelectric conversion unit 41d and the supply unit 67.

During the period from time t43 to time t45, when the reset signal RstR and pixel signal Sig1R+2R are read out, signals TX_1L_2 and TX_2L_2 are both high. When signal TX_1L_2 is high, transistor M8a of the third discharge unit 46a is turned on, electrically connecting the second photoelectric conversion unit 41a and the supply unit 67. When signal TX_2L_2 is high, transistor M8c of the third discharge unit 46c is turned on, electrically connecting the second photoelectric conversion unit 41c and the supply unit 67.

In this way, in this modified example, the readout control unit 70 can discharge the charge accumulated in the second photoelectric conversion unit 41 to the supply unit 67 by turning on the third discharge unit 46. The second photoelectric conversion unit 41 is reset, which can prevent the charge in the second photoelectric conversion unit 41 from saturating and leaking into other photoelectric conversion units, storage units, etc. This can prevent noise from being mixed into the pixel signal.

(Variation 2)
FIG. 10 is a diagram illustrating an example of the configuration of a pixel of an image sensor according to Modification 2. In the example illustrated in FIG. 10( a), a light-shielding portion 54 is provided to cover the periphery of each of the first photoelectric conversion portion 11 and the plurality of second photoelectric conversion portions 41. The light-shielding portion (light-shielding film) 54 is formed of a conductor film or the like. The light-shielding portion 54 is, for example, aluminum, copper, tungsten, or a multilayer film of these films. The light-shielding portion 54 is provided to cover the region (Tr region) in which transistors such as the amplifier portion 16 and the selector portion 17 constituting the pixel 10 are arranged. The light-shielding portion 54 prevents light from entering the Tr region, thereby preventing noise from being mixed into the pixel signal. Alternatively, as illustrated in FIG. 10( b), a light-shielding portion 54a may be provided to cover the periphery of the first photoelectric conversion portion 11, and a light-shielding portion 54b may be provided to cover the periphery of the second photoelectric conversion portions 41a to 41d.

(Variation 3)
As shown in FIG. 11 , an insulating section 58 may be provided around the first photoelectric conversion section 11 and the plurality of second photoelectric conversion sections 41. The insulating section 58 is an insulating layer made of an insulating material and is configured by deep trench isolation (DTI). As shown in FIGS. 11( a) and 11(b), insulating sections 58a and 58b may be provided to surround the first photoelectric conversion section 11 and the plurality of second photoelectric conversion sections 41, respectively. The insulating section 58 separates the photoelectric conversion sections and can prevent charge generated in one photoelectric conversion section from leaking to another photoelectric conversion section. Alternatively, as shown in FIG. 11(c), an insulating section 58c may be provided to surround the first photoelectric conversion section 11, and an insulating section 58d may be provided to surround the second photoelectric conversion sections 41a to 41d.

(Variation 4)
In the above-described embodiment and modified examples, exemplary configurations of the pixel 10 have been described, but these are merely examples and are not limited to the above-described examples. For example, the number and arrangement of the second photoelectric conversion units 41 are not limited to the above-described examples. The pixel 10 may be configured to have two or three second photoelectric conversion units 41, or may be configured to have five or more second photoelectric conversion units 41. For example, the pixel 10 may be configured to have one first photoelectric conversion unit 11 and two of the four second photoelectric conversion units 41a to 41d (PD1L, PD1R, PD2L, PD2R). Furthermore, for example, as shown in FIG. 12( a), eight second photoelectric conversion units 41 may be arranged per pixel.

As shown in Figures 12(b) and (c), a microlens 51 may be provided for each photoelectric conversion unit. Note that in the example shown in Figure 12(c), a total of six pixels 10 are illustrated. A light-shielding unit 56 that blocks part of the light incident on the second photoelectric conversion unit 41 may be provided between the second photoelectric conversion unit 41 and the microlens 51b in the Z-axis direction. Each light-shielding unit 56 provided for each second photoelectric conversion unit 41 may be positioned so that light that has passed through different regions of the exit pupil of the imaging optical system 31 enters the second photoelectric conversion unit 41.

Microlenses 51a and 51b of different heights (thickness in the Z-axis direction) may be provided for the first photoelectric conversion unit 11 and the second photoelectric conversion unit 41. The height of microlens 51b may be greater than the height of microlens 51a so that incident light is focused at a position closer to the light-shielding unit 56 than to the second photoelectric conversion unit 41. The shape of the microlenses 51 (51a, 51b) can be changed as appropriate, as shown in the examples in Figures 12(b) and (c), and may be circular or polygonal.

(Variation 5)
In the above-described embodiment and modified example, a photodiode is used as the photoelectric conversion unit. However, a photoelectric conversion film (organic photoelectric film) may be used as the photoelectric conversion unit.

(Variation 6)
The imaging elements and imaging devices described in the above-mentioned embodiments and variations may be applied to cameras, smartphones, tablets, cameras built into PCs, in-vehicle cameras, cameras mounted on unmanned aerial vehicles (drones, radio-controlled aircraft, etc.), etc.

Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the technical spirit of the present invention are also included within the scope of the present invention.

1...imaging device, 10...pixel, 11...first photoelectric conversion unit, 12...first transfer unit, 14...first storage unit, 15...first discharge unit, 18...second discharge unit, 21...image sensor, 25...body control unit, 25a...imaging control unit, 25b...image processing unit, 25c...focus detection unit, 41...second photoelectric conversion unit, 42...second transfer unit, 44...second storage unit, 45...connection unit, 46...third discharge unit, 51...microlens, 70...readout control unit

Claims (16)

a microlens onto which light is incident;
a first photoelectric conversion unit that converts light transmitted through the microlens into electric charges and has a first light-receiving area;
a second photoelectric conversion unit that converts light transmitted through the microlens into electric charges and has a second light receiving area larger than the first light receiving area;
a third photoelectric conversion unit that converts light transmitted through the microlens into electric charges and has a third light receiving area that is larger than the first light receiving area;
a first accumulation unit to which the charges converted by the first photoelectric conversion unit are transferred;
a second accumulation unit to which the charges converted by the second photoelectric conversion unit and the charges converted by the third photoelectric conversion unit are transferred;
a first transfer unit for transferring the charges converted by the first photoelectric conversion unit to the first accumulation unit;
a second transfer unit for transferring the charges converted by the second photoelectric conversion unit to the second accumulation unit;
a third transfer unit for transferring the charges converted by the third photoelectric conversion unit to the second accumulation unit;
a connection portion for electrically connecting the first storage portion and the second storage portion,
the second photoelectric conversion unit is disposed at a position farther from the optical axis of the microlens than the first photoelectric conversion unit ,
the third photoelectric conversion unit is disposed at a position farther from the optical axis of the microlens than the first photoelectric conversion unit.
Image sensor. 2. The imaging device according to claim 1,
the first photoelectric conversion unit is disposed at a position where the optical axis of the microlens passes;
Image sensor. 3. The imaging device according to claim 1 ,
An imaging device comprising a first drain section that drains the charges from the first storage section. 4. The imaging device according to claim 3 ,
An imaging element including a second discharge unit that discharges electric charges from the first photoelectric conversion unit. 5. The imaging device according to claim 4 ,
an imaging element including a third discharge section that discharges the electric charge of the second photoelectric conversion section; 6. The imaging device according to claim 1,
an imaging element including a control unit that controls timing for electrically connecting the first storage unit and the second storage unit by the connection unit; 6. The imaging device according to claim 5 ,
a third discharge unit that discharges the charges of the second photoelectric conversion unit;
a fourth discharge unit that discharges the electric charge of the third photoelectric conversion unit. The imaging device according to any one of claims 1 to 7 ,
the first photoelectric conversion unit is disposed between the second photoelectric conversion unit and the third photoelectric conversion unit in a direction perpendicular to an optical axis direction of the microlens;
Image sensor. The imaging device according to any one of claims 1 to 7 ,
the second photoelectric conversion unit and the third photoelectric conversion unit are arranged to sandwich the first photoelectric conversion unit in a direction perpendicular to the optical axis direction of the microlens.
Image sensor. 10. The imaging device according to claim 1 ,
an imaging element including a control unit that controls timing for electrically connecting the first storage unit and the second storage unit by the connection unit; An imaging device comprising the imaging element according to any one of claims 1 to 10 . 12. The imaging device according to claim 11 ,
An imaging device comprising an image processing unit that generates image data using a signal based on charges converted by the first photoelectric conversion unit, out of a signal based on charges converted by the first photoelectric conversion unit and a signal based on charges converted by the second photoelectric conversion unit. 13. The imaging device according to claim 12 ,
the image processing unit generates image data using only the signal based on the charges converted by the first photoelectric conversion unit out of the signal based on the charges converted by the first photoelectric conversion unit and the signal based on the charges converted by the second photoelectric conversion unit.
Imaging device. 14. The imaging device according to claim 11 ,
An imaging device including a focus detection unit that calculates a defocus amount using the signal based on the charges converted by the second photoelectric conversion unit, out of the signals based on the charges converted by the first photoelectric conversion unit and the signals based on the charges converted by the second photoelectric conversion unit. 15. The imaging device according to claim 14 ,
the focus detection unit calculates a defocus amount using only the signal based on the charges converted by the second photoelectric conversion unit out of the signal based on the charges converted by the first photoelectric conversion unit and the signal based on the charges converted by the second photoelectric conversion unit;
Imaging device. 16. The imaging device according to claim 11 ,
An imaging device comprising an optical system that emits light to the imaging element.