Imaging element

Abstract

To improve accuracy of focus detection.SOLUTION: An imaging element includes: a first discharge part, having a first photoelectric conversion part, a second photoelectric conversion part, a first floating diffusion, and a first transistor, for discharging charge at the first floating diffusion; a first output part for outputting a first signal based on the charge transferred from the second photoelectric conversion part to the first floating diffusion and for outputting a second signal used for first signal processing of the first signal based on the charge at the first floating diffusion when the first transistor in the first discharge part is on state including a duration during which the charge transferred from the first photoelectric conversion part to the first floating diffusion is being discharged, to the first signal line; and a first signal processing part for performing first signal processing using a first digital signal converted from the first signal outputted to the first signal line to a digital signal, and a second digital signal converted from the second signal outputted to the first signal line to a digital signal.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an imaging device. [Background technology]

[0002] Focus detection techniques using focus detection pixels have been known for some time, and there has been a demand for improved focus detection accuracy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-263568 Summary of the Invention

[0004] According to a first aspect, an imaging device includes a first photoelectric conversion unit that converts light into electric charges, a second photoelectric conversion unit that converts light into electric charges, a first floating diffusion to which the electric charges converted by the first photoelectric conversion unit and the electric charges converted by the second photoelectric conversion unit are transferred, a first transistor for electrically connecting the first floating diffusion to a wiring to which a predetermined voltage is supplied, a first drain unit that drains the electric charges of the first floating diffusion, a first signal based on the electric charges transferred from the second photoelectric conversion unit to the first floating diffusion, and a first signal corresponding to the first signal. The device is equipped with a first output unit that outputs to a first signal line a signal used for signal processing, the second signal being based on the charge of the first floating diffusion when the first transistor of the first discharge unit is in an on state, including a period during which the charge transferred from the first photoelectric conversion unit to the first floating diffusion by the first discharge unit is discharged, and a first signal processing unit that performs the first signal processing using a first digital signal converted from the first signal output to the first signal line and a second digital signal converted from the second signal output to the first signal line. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a diagram illustrating an example of the configuration of an imaging device according to a first embodiment. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of an imaging element according to a first embodiment. [Figure 3] 1 is a diagram illustrating an example of the configuration of a portion of an imaging element according to a first embodiment. [Figure 4] 3A to 3C are diagrams illustrating an example of the operation of the imaging element according to the first embodiment. [Figure 5] 4 is a timing chart showing an example of the operation of the imaging element according to the first embodiment. [Figure 6] 3A to 3C are diagrams illustrating an example of the operation of the imaging element according to the first embodiment. [Figure 7] 4 is a timing chart showing an example of the operation of the imaging element according to the first embodiment. [Figure 8] 4 is a timing chart showing an example of the operation of the imaging element according to the first embodiment. [Figure 9] FIG. 10 is a diagram illustrating an example of the configuration of a portion of an imaging element according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0006] (First 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 a first embodiment. The camera 1 includes a photographing optical system (imaging optical system) 2, an image sensor 3, a control unit 4, a memory 5, a display unit 6, and an operation unit 7. The photographing optical system 2 has multiple lenses, including a focus adjustment lens (focus lens), and an aperture stop, and forms a subject image on the image sensor 3. The photographing optical system 2 may be detachable from the camera 1.

[0007] The imaging element 3 is an imaging element such as a CMOS image sensor or a CCD image sensor. The imaging element 3 receives a light beam that has passed through the photographing optical system 2 and captures an image of a subject formed by the photographing optical system 2. The imaging element 3 has a plurality of pixels, each having a photoelectric conversion unit, arranged two-dimensionally (in the row and column directions). The photoelectric conversion unit is composed of a photodiode (PD). The imaging element 3 photoelectrically converts the received light to generate a signal and outputs the generated signal to the control unit 4.

[0008] The image sensor 3 has imaging pixels and AF pixels (focus detection pixels). The imaging pixels output signals used for image generation. The AF pixels output signals used for focus detection. As will be described later, the AF pixels are arranged to replace some of the imaging pixels, and are distributed over almost the entire imaging surface of the image sensor 3. In the following description, when simply referring to pixels, this refers to either or both of the imaging pixels and the AF pixels.

[0009] The memory 5 is a recording medium such as a memory card. Image data, control programs, etc. are recorded in the memory 5. Writing data to the memory 5 and reading data from the memory 5 are controlled by the control unit 4. The display unit 6 displays an image based on the image data, information related to shooting such as the shutter speed and aperture value, and a menu screen, etc. The operation unit 7 includes various setting switches such as a release button, a power switch, and switches for switching between various modes, and outputs signals to the control unit 4 based on the respective operations.

[0010] The control unit 4 is configured with a processor such as a CPU, FPGA, or ASIC, and memories such as a ROM or RAM, and controls each unit of the camera 1 based on a control program. The control unit 4 has an imaging control unit 4a, an image data generation unit 4b, and a focus detection unit 4c.

[0011] The imaging control unit 4a supplies signals for controlling the imaging element 3 to the imaging element 3, thereby controlling the operation of the imaging element 3. When displaying a through image (live view image) of a subject on the display unit 6 or when shooting video, the imaging control unit 4a causes the imaging element 3 to repeatedly capture an image of the subject for each frame at a predetermined cycle and output a signal. The imaging control unit 4a performs readout control using a so-called rolling shutter method, in which the pixels of the imaging element 3 are selected row by row in sequence and signals are read out from the selected pixels.

[0012] The imaging control unit 4a controls the image sensor 3 to separately read out signals from pixel rows in which AF pixels are arranged (hereinafter referred to as AF pixel rows) and from pixel rows in which AF pixels are not arranged (hereinafter referred to as imaging pixel rows).The imaging control unit 4a also sequentially selects pixel rows and reads out signals from each pixel, without separately reading out signals from AF pixel rows and imaging pixel rows.

[0013] For example, when displaying a through image on the display unit 6 or when capturing a moving image, the imaging control unit 4a separately reads out the signals of each pixel in the AF pixel row and the signals of each pixel in the imaging pixel row. When capturing a high-resolution still image, the imaging control unit 4a does not separately read out the signals of each pixel in the AF pixel row and the signals of each pixel in the imaging pixel row, but instead selects pixel rows sequentially and reads out the signals.

[0014] The image data generation unit 4b generates image data (still image data, moving image data) by performing various image processing on signals output from the imaging pixels of the image sensor 3. Image processing includes image processing such as tone conversion processing and color interpolation processing. Note that the image data generation unit 4b may also generate image data using signals output from the AF pixels.

[0015] The focus detection unit 4c performs focus detection processing required for automatic focusing (AF) of the photographing optical system 2. The focus detection unit 4c detects the in-focus position of the focus lens (the amount of movement of the focus lens to the in-focus position) for the image by the photographing optical system 2 to be focused (formed) on the imaging surface of the image sensor 3. The focus detection unit 4c calculates the defocus amount by a phase difference detection method using first and second signals output from a pair of AF pixels (AF pixel pair) of the image sensor 3.

[0016] The focus detection unit 4c calculates the amount of image shift by performing a correlation calculation between a first signal generated by capturing an image formed by a first light beam that passed through a first region of the exit pupil of the photographing optical system 2 and a second signal generated by capturing an image formed by a second light beam that passed through a second region. The focus detection unit 4c converts this amount of image shift into a defocus amount using a predetermined conversion formula. Based on the calculated defocus amount, the focus detection unit 4c calculates the amount of movement of the focus lens to the in-focus position. The focus lens is driven according to the amount of movement, thereby automatically adjusting the focus. In this way, the control unit 4 controls the position of the focus lens so that the image of the subject formed by the photographing optical system 2 is focused on the image sensor 3.

[0017] FIG. 2 is a diagram showing an example of the configuration of an image sensor according to the first embodiment. The image sensor 3 has a pixel section (pixel region) 100 in which pixels are arranged two-dimensionally (in the row and column directions), a supply section 30, a readout control section 40, and a plurality of processing sections 50 (processing sections 50a to 50h). A plurality of image pixels 10 and AF pixels 13 (13a, 13b) are arranged in the pixel section 100 of the image sensor 3. In FIG. 2, the pixel in the upper left corner is image pixel 10(1,1) in the first row and first column, and the pixel in the lower right corner is image pixel 10(16,8) in the 16th row and eighth column, for a total of 128 pixels in 16 rows and 8 columns. Note that the number and arrangement of pixels arranged in the image sensor 3 are not limited to the example shown in the figure.

[0018] Each imaging pixel 10 is provided with one of three color filters 41 having different spectral characteristics of red (R), green (G), or blue (B). The imaging pixels 10 include pixels (hereinafter referred to as R pixels) having color filters 41 with spectral characteristics that separate incident light in a first wavelength range (red (R) light), pixels (hereinafter referred to as G pixels) having color filters 41 with spectral characteristics that separate incident light in a second wavelength range (green (G) light), and pixels (hereinafter referred to as B pixels) having color filters 41 with spectral characteristics that separate incident light in a third wavelength range (blue (B) light). The R pixels 10, G pixels 10, and B pixels 10 are arranged according to a Bayer array.

[0019] The first AF pixel 13a and the second AF pixel 13b are arranged to replace some of the R, G, and B imaging pixels 10 arranged in a Bayer array as described above. In the example shown in FIG. 2, color filters 41 having spectral characteristics that separate incident light in a second wavelength range (green (G) light) are arranged in the first AF pixel 13a and the second AF pixel 13b. The color filters in the first and second AF pixels 13a and 13b may be color filters having spectral characteristics that separate incident light in a first wavelength range (red (R) light) or a third wavelength range (blue (B) light). The first and second AF pixels 13a and 13b may also have filters having spectral characteristics that separate incident light into first, second, and third wavelength ranges. Alternatively, color filters may not be arranged in the first and second AF pixels 13a and 13b.

[0020] The first AF pixel 13a and the second AF pixel 13b each have a light-shielding portion 43 that blocks a portion of light incident on the photoelectric conversion unit. The first AF pixel 13a and the second AF pixel 13b have light-shielding portions 43 located at different positions. The light-shielding portions 43 of the first AF pixel 13a and the second AF pixel 13b are arranged so that light that has passed through different regions of the exit pupil of the photographing optical system 2 enters the photoelectric conversion unit. As a result, the photoelectric conversion unit of the first AF pixel 13a receives a light beam that has passed through a first region of the first and second regions of the exit pupil of the photographing optical system 2. The photoelectric conversion unit of the second AF pixel 13b receives a light beam that has passed through a second region of the first and second regions of the exit pupil of the photographing optical system 2.

[0021] 2, the image sensor 3 has a pixel group (first imaging pixel row) 401 in which G pixels 10 and B pixels 10 are alternately arranged in the left-right direction, i.e., the row direction, and a pixel group (second imaging pixel row) 402 in which R pixels 10 and G pixels 10 are alternately arranged in the row direction. The image sensor 3 also has a pixel group (first AF pixel row) 403a in which G pixels 10 and first AF pixels 13a are alternately arranged in the row direction, and a pixel group (second AF pixel row) 403b in which G pixels 10 and second AF pixels 13b are alternately arranged in the row direction. A plurality of the first imaging pixel row 401, second imaging pixel row 402, first AF pixel row 403a, and second AF pixel row 403b are each arranged in the up-down direction, i.e., the column direction.

[0022] In the image sensor 3, a vertical signal line 25 is provided for each of a plurality of pixels 10 arranged in the horizontal direction (row direction). It can also be said that a vertical signal line 25 is provided for each pixel column, which is a row of a plurality of pixels lined up in the vertical direction (column direction). A current source and a processing unit 50, which will be described later, are provided for each of the plurality of vertical signal lines 25 (vertical signal lines 25a to 25h in FIG. 2).

[0023] The supply unit 30 is controlled by the imaging control unit 4a of the camera 1 and supplies a predetermined voltage (electric potential) to each pixel. As will be described later, the supply unit 30 supplies a power supply voltage VDD to the imaging pixels 10 and the AF pixels 13 via a supply unit 35 (see FIG. 3).

[0024] The readout control unit 40 is composed of multiple circuits including a timing generator. The readout control unit 40 is controlled by the imaging control unit 4a and supplies signals such as a signal TX, a signal RST, and a signal SEL (described later) to each pixel to control the operation of each pixel. The readout control unit 40 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 a vertical signal line 25 connected to that pixel.

[0025] The processing unit 50 is configured to include an analog / digital conversion unit (AD conversion unit). The processing unit 50 converts analog pixel signals input from each pixel via the vertical signal line 25 into digital signals. The processing unit 50 may also have an amplifier unit that amplifies the pixel signals input via the vertical signal line 25 by a predetermined gain (amplification factor). In this case, the processing unit 50 may convert the pixel signals amplified by the amplifier unit into digital signals.

[0026] The processing unit 50 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 control unit 4.

[0027] 3 is a diagram showing an example of the configuration of a portion of the image sensor according to the first embodiment. Each pixel (AF pixel 13, imaging pixel 10) includes a photoelectric conversion unit 11 and a connection unit 12. Of two pixels adjacent to each other in the column direction, one pixel (AF pixel 13) has a photoelectric conversion unit 11a and a connection unit 12a, and the other pixel (imaging pixel 10) has a photoelectric conversion unit 11b and a connection unit 12b. The photoelectric conversion units 11 (11a, 11b) are photodiodes PD that convert incident light into electric charges and store the photoelectrically converted electric charges.

[0028] As indicated by dashed lines 20 in Fig. 3, the image sensor 3 has a configuration in which two adjacent pixels share a floating diffusion (FD) 14, a connection unit 15, an amplifier unit 16, and a selection unit 17. In this embodiment, the circuit configurations of two adjacent imaging pixels 10 are the same as the circuit configurations of the AF pixel 13 and the imaging pixel 10 shown in Fig. 3. In the example shown in Fig. 3, the connection units 12a, 12b, and 15 can each be considered to be switching units (switch units) that switch between connection and disconnection.

[0029] The supply unit 35 is a part (wiring, electrodes, etc.) of the imaging element 3 that supplies (applies) the power supply voltage VDD to the connection unit 15 and the amplifier unit 16. The supply unit 35 is given the power supply voltage VDD from the supply unit 30 (see FIG. 2). Note that the supply unit 35 may be part of the supply unit 30.

[0030] The connection unit 12a is composed of a transistor M1a controlled by a signal TX1, and electrically connects or disconnects the photoelectric conversion unit 11a and the FD 14. The connection unit 12a is a transfer unit 12a, and transfers the charges photoelectrically converted by the photoelectric conversion unit 11a to the FD 14.

[0031] The connection unit 12b is composed of a transistor M1b controlled by a signal TX2, and electrically connects or disconnects the photoelectric conversion unit 11b and the FD14. The connection unit 12b is a transfer unit 12b, and transfers the charges photoelectrically converted by the photoelectric conversion unit 11b to the FD14. The transistors M1a and M1b are each a transfer transistor. The capacitance C of the FD14 accumulates (holds) the charges transferred to the FD14 and converts them into a voltage divided by the capacitance value. The FD14 is a storage unit 14, and accumulates the charges generated by the photoelectric conversion unit 11b.

[0032] The amplifier unit 16 is composed of a transistor M3 whose gate (terminal) is connected to the FD 14, and amplifies and outputs a signal due to the charge accumulated in the capacitance C of the FD 14. The drain (terminal) and source (terminal) of the transistor M3 are connected to a supply unit 35 that supplies a power supply voltage VDD and a selection unit 17, respectively. The amplifier unit 16 functions as part of a source follower circuit, with a current source 26 as a load current source. The transistor M3 is an amplifying transistor. The amplifier unit 16 and the selection unit 17 constitute an output unit that generates and outputs a signal based on the charge generated by the photoelectric conversion unit 11.

[0033] The connection unit 15 is composed of a transistor M2 controlled by a signal RST, and electrically connects or disconnects the supply unit 35 and the FD14. The connection unit 15 connects the supply unit 35 and the FD14, thereby discharging the charge accumulated by the FD14 to the supply unit 35. The connection unit 15 is a discharge unit (reset unit) 15, which discharges the charge accumulated in the FD14 and resets the voltage of the FD14. The transistor M2 is a reset transistor.

[0034] The selection unit 17 is composed of a transistor M4 controlled by a signal SEL, and electrically connects or disconnects the amplification unit 16 and the vertical signal line 25. When the transistor M4 of the selection unit 17 is in an on state, it outputs a signal from the amplification unit 16 to the vertical signal line 25. The transistor M4 is a selection transistor.

[0035] The current source 26 is connected to each pixel via a vertical signal line 25. The current source 26 generates a current for reading out a signal from the pixel, and supplies the generated current to the vertical signal line 25 and the amplifier unit 16 and selector unit 17 of each pixel.

[0036] The image sensor 3 performs a reset operation to discharge charges accumulated in the photoelectric conversion units 11 of pixels and a readout operation to read signals from the pixels. In a reset operation for the AF pixel 13 shown in Fig. 3, the charges accumulated in the photoelectric conversion unit 11a are discharged to the supply unit 35 via the transfer unit 12a, the FD 14, and the connection unit 15. In a reset operation for the image pixel 10, the charges accumulated in the photoelectric conversion unit 11b are discharged to the supply unit 35 via the transfer unit 12b, the FD 14, and the connection unit 15.

[0037] In this embodiment, the imaging control unit 4a performs reading control using a rolling shutter method. The imaging pixel rows and AF pixel rows of the image sensor 3 are sequentially selected by the read control unit 40. In the image sensor 3, reset operations and read operations are performed while scanning each row, for example, from the top row to the bottom row. The imaging control unit 4a controls the read control unit 40 to perform a first read process in which all pixel rows are sequentially selected and signals from each pixel are read, and a second read process in which signals from each pixel in the AF pixel rows and signals from each pixel in the imaging pixel rows are read separately.

[0038] 4 is a diagram showing an example of the operation of the image sensor according to the first embodiment, illustrating an example of the operation when a first readout process is performed to read out pixel signals. The vertical axis indicates pixel rows, and the horizontal axis indicates the timing (time t) at which the reset operation and readout operation of each pixel row are performed. FIG. 4 schematically illustrates the transition of pixel rows at which the reset operation and readout operation are performed.

[0039] When the imaging control unit 4a instructs the first readout process, the readout control unit 40 sequentially selects pixel rows and causes each pixel to output a signal, as shown in Fig. 4. In the example shown in Fig. 2, the readout control unit 40 sequentially selects pixel rows from the first row to the sixteenth row. The readout control unit 40 causes each pixel in the selected pixel row to output a signal to the vertical signal line 25. An example of a signal readout method for the first readout process will be described below.

[0040] The readout control unit 40 turns on the transfer units 12a of the G pixels 10(1,1) to B pixels 10(1,8), which are pixels in the first imaging pixel row 401 in the first row. The readout control unit 40 also turns off the transfer units 12 (transfer units 12a and 12b) of the pixels in rows other than the first row. As a result, the charges photoelectrically converted by the photoelectric conversion units 11a of the G pixels 10(1,1) to B pixels 10(1,8) in the first row are transferred to the FD 14. The signals of the G pixels 10(1,1) to B pixels 10(1,8) in the first row are output to the vertical signal lines 25a to 25h, respectively, via the selection units 17 of the respective pixels.

[0041] The readout control unit 40 turns on the transfer units 12b of the R pixels 10(2,1) to G pixels 10(2,8), which are pixels in the second imaging pixel row 402 in the second row, and turns off the transfer units 12 (transfer units 12a and 12b) of the pixels in rows other than the second row. As a result, the charges photoelectrically converted by the respective photoelectric conversion units 11b in the R pixels 10(2,1) to G pixels 10(2,8) in the second row are transferred to the FD 14. The signals of the R pixels 10(2,1) to G pixels 10(2,8) in the second row are output to the vertical signal lines 25a to 25h, respectively, via the selection units 17 of the respective pixels.

[0042] The readout control unit 40 turns on the transfer units 12a of the G pixel 10(3,1) to the first AF pixel 13a(3,8), which are pixels in the first AF pixel row 403a in the third row, and turns off the transfer units 12 (transfer units 12a and 12b) of the pixels in rows other than the third row. Charges photoelectrically converted by the photoelectric conversion units 11a of the G pixel 10(3,1) to the first AF pixel 13a(3,8) in the third row are transferred to the FD 14. The signals of the G pixel 10(3,1) to the first AF pixel 13a(3,8) in the third row are output to the vertical signal lines 25a to 25h, respectively, via the selection units 17 of the respective pixels. Similarly, the readout control unit 40 sequentially selects pixels from the fourth row onwards, row by row, in the order of the fourth row, fifth row, sixth row, and seventh row, and reads out signals from each of the selected pixels.

[0043] In this way, in the first readout process, the readout control unit 40 sequentially selects all pixel rows and reads out signals from each pixel. The pixel signals output to the vertical signal lines 25a to 25h are processed by the processing units 50a to 50h, respectively, and then output to the control unit 4.

[0044] Next, the above-mentioned readout operation will be further described using an example in which signals from the imaging pixels 10 in an imaging pixel row are read out. FIG. 5 is a diagram showing an example of a readout operation of pixels in the image sensor according to the first embodiment. In the timing chart shown in FIG. 5, the horizontal axis represents time, and indicates control signals input to the pixels of the image sensor 3. In FIG. 5, transistors receiving high-level (e.g., power supply voltage VDD) control signals (signals SEL, RST, and TX) are turned on, and transistors receiving low-level (e.g., ground voltage) control signals are turned off. Note that, before time t1 shown in FIG. 5, a reset operation prior to the readout operation is performed as shown in FIG. 4, and the charges accumulated in the photoelectric conversion units 11 of each pixel in the imaging pixel row to be read out are reset.

[0045] At time t1 shown in Figure 5, signal RST goes high. When signal RST goes high, transistor M2 of connection unit 15 shared by imaging pixels 10 in the imaging pixel row to be read and AF pixels 13 in the AF pixel row adjacent to that imaging pixel row is turned on. When connection unit 15 is turned on, FD 14 and supply unit 35 are electrically connected. As a result, the charge of FD 14 shared by AF pixels 13 and imaging pixels 10 is reset, and the voltage of FD 14 becomes the reset voltage.

[0046] Also, at time t1, the signal SEL goes high. When the signal SEL goes high, the transistor M4 of the selection unit 17, which is shared by the AF pixel 13 and the imaging pixel 10, goes on. As a result, a signal based on the reset voltage of the imaging pixel 10, i.e., a signal obtained after the charge of the FD 14 of the imaging pixel 10 has been reset, is output to the vertical signal line 25 by the amplifier unit 16 and the selection unit 17. The signal based on the reset voltage of the imaging pixel 10 is input to the processing unit 50 via the vertical signal line 25 as a dark signal. The dark signal is an analog signal based on the reset voltage, and is converted into a digital signal by the processing unit 50.

[0047] At time t2, the signal TX2 goes high. When the signal TX2 goes high, the transistor M1b of the transfer unit 12b in the imaging pixel 10 is turned on, electrically connecting the photoelectric conversion unit 11b and the FD14. This causes the charges photoelectrically converted by the photoelectric conversion unit 11b to be transferred to the FD14. Also, because the signal SEL is high, a signal corresponding to the charges transferred to the FD14, i.e., a signal (pixel signal) based on the charges generated by the photoelectric conversion unit 11b of the imaging pixel 10, is output to the vertical signal line 25 by the amplifier 16 and the selector 17. The pixel signal of the imaging pixel 10 is input to the processing unit 50 via the vertical signal line 25. The pixel signal is an analog signal generated based on the charges photoelectrically converted by the photoelectric conversion unit 11, and is converted into a digital signal by the processing unit 50. At time t3, the signal SEL goes low, turning off the transistor M4 of the selector 17.

[0048] The processing unit 50 performs signal processing such as correlated double sampling using the dark signal converted into a digital signal and the pixel signal. The pixel signal of the imaging pixel 10 is output to the control unit 4 of the camera 1 after signal processing such as correlated double sampling is performed by the processing unit 50. Note that the pixel signal of the first AF pixel 13a and the pixel signal of the second AF pixel 13b are output to the control unit 4 as a pair of signals (first and second signals) after signal processing by the processing unit 50.

[0049] 6 is a diagram showing an example of the operation of the image sensor according to the first embodiment, illustrating an example of the operation when performing a second readout process to read out pixel signals. The vertical axis indicates pixel rows, and the horizontal axis indicates the timing (time t) at which the reset operation and readout operation of each pixel row are performed. FIG. 6 schematically illustrates the transition of pixel rows at which the reset operation and readout operation are performed.

[0050] When the imaging control unit 4a instructs the second readout process, the readout control unit 40 separately reads out the signals of each pixel in the AF pixel row and the signals of each pixel in the imaging pixel row. As shown in Fig. 6, the readout control unit 40 performs a reset operation and readout operation for the imaging pixel row, and also performs a reset operation and readout operation for the AF pixel row.

[0051] When reading out signals from the AF pixel rows (the first AF pixel row 403a and the second AF pixel row 403b), the readout control unit 40 sequentially selects the multiple AF pixel rows of the image sensor 3 from the top row to the bottom row and reads out signals from each pixel. When reading out signals from the imaging pixel rows (the first imaging pixel row 401 and the second imaging pixel row 402), the readout control unit 40 sequentially selects the multiple imaging pixel rows of the image sensor 3 from the top row to the bottom row and reads out signals from each pixel. In this embodiment, as schematically shown in FIG. 2, the number of AF pixel rows is smaller than the number of imaging pixel rows. In the example shown in FIG. 6, the total number of AF pixel rows on which the reset operation and readout operation are performed is smaller than the total number of imaging pixel rows on which the reset operation and readout operation are performed, and the time required for scanning the AF pixel rows is shorter than that for scanning the imaging pixel rows.

[0052] In this way, in the second readout process, signals from each pixel in the AF pixel row are read out separately from signals from each pixel in the imaging pixel row, so signals used for focus detection can be obtained efficiently and the burden of signal processing for AF can be reduced. When the second readout process is instructed, the readout control unit 40 may read signals from each pixel in the AF pixel row before reading signals from the imaging pixel row. In this case, the first and second signals of the AF pixel pair can be read out quickly, thereby shortening the time required for focus adjustment. Furthermore, the readout control unit 40 may read signals from each pixel in the imaging pixel row before reading signals from the AF pixel row.

[0053] 6, within dotted-line frame G1, there are cases where the readout operation of an imaging pixel row and the reset operation of an AF pixel row adjacent to that imaging pixel row are performed simultaneously. Also, within dotted-line frame G2, there are cases where the readout operation of an AF pixel row and the reset operation of an imaging pixel row adjacent to that AF pixel row are performed simultaneously.

[0054] During the period within the dotted-line frame G1, the readout control unit 40 turns on the connection unit 15 of each pixel in the imaging pixel row to be read out in order to read out a signal (dark signal) based on the reset voltage. For each pixel in the imaging pixel row to be read out, the connection unit 15 shared by the pixels in the imaging pixel row and the pixels in the AF pixel row adjacent to that imaging pixel row is turned on. When the connection unit 15 is turned on, the FD 14 and the supply unit 35 are electrically connected. As a result, the charge in the FD 14 is discharged to the supply unit 35 in each pixel in the imaging pixel row.

[0055] While the connection units 15 of each pixel in an imaging pixel row are in the ON state to read out dark signals, the readout control unit 40 turns on the transfer units 12 of each pixel in the AF pixel row adjacent to that imaging pixel row. When the transfer units 12 and connection units 15 of the pixels in the AF pixel row are both in the ON state, the photoelectric conversion units 11, FDs 14, and supply units 35 of the pixels in the AF pixel row are electrically connected. As a result, in each pixel in the AF pixel row, the charge in the photoelectric conversion unit 11 is discharged to the supply unit 35, and the voltage of the photoelectric conversion unit 11 is reset. In this way, in parallel with the readout operation of the imaging pixel row, a reset operation is performed to discharge the charge in the photoelectric conversion unit 11 of each pixel in the AF pixel row adjacent to that imaging pixel row.

[0056] After the charge in the photoelectric conversion unit 11 of each pixel in the AF pixel row has been discharged, the readout control unit 40 turns off the transfer unit 12 of each pixel in the AF pixel row. Because the connection unit 15 shared by the pixels in the imaging pixel row to be readout and the pixels in the AF pixel row is on, the voltage of the FD 14 is in a reset state. When the selection unit 17 shared by the pixels in the imaging pixel row to be readout and the pixels in the AF pixel row is on, a dark signal based on the reset voltage of each pixel in the imaging pixel row is output via the selection unit 17 of each pixel to the vertical signal line 25 connected to that pixel.

[0057] After the dark signals of each pixel in the imaging pixel row have been read out, the readout control unit 40 turns on the transfer unit 12 of each pixel in the imaging pixel row. In each pixel in the imaging pixel row, the charge photoelectrically converted by the respective photoelectric conversion unit 11 is transferred to the FD 14. The pixel signal of each pixel in the imaging pixel row is output to the vertical signal line 25 connected to that pixel via the selection unit 17 of that pixel.

[0058] As described above, the readout control unit 40 turns on the transfer units 12 of the pixels in the AF pixel row during a period in which the connection units 15 are turned on to read out the dark signals, and connects the photoelectric conversion units 11 of the pixels in the AF pixel row to the supply unit 35 via the transfer units 12 and the connection units 15. This causes the charge accumulated in the photoelectric conversion units 11 of each pixel in the AF pixel row to be discharged to the supply unit 35, resetting the voltage of the photoelectric conversion unit 11. In this way, the image sensor 3 according to this embodiment can perform a reset operation on the AF pixel row adjacent to the imaging pixel row even during a period in which the readout operation for that imaging pixel row is being performed.

[0059] During the period within the dotted-line frame G2, the readout control unit 40 turns on the connection unit 15 of each pixel in the AF pixel row to be read out in order to read out the dark signal. For each pixel in the AF pixel row to be read out, the connection unit 15 shared by the pixels in the AF pixel row and the pixels in the imaging pixel row adjacent to that AF pixel row is turned on. This causes the charge in the FD 14 in each pixel in the AF pixel row to be discharged to the supply unit 35.

[0060] While the connection units 15 of each pixel in an AF pixel row are in the ON state to read out dark signals, the readout control unit 40 turns on the transfer units 12 of each pixel in an imaging pixel row adjacent to the AF pixel row. When the transfer units 12 and connection units 15 of the pixels in the imaging pixel row are both in the ON state, the photoelectric conversion units 11, FDs 14, and supply units 35 of the pixels in the imaging pixel row are electrically connected. As a result, the charge in the photoelectric conversion units 11 of each pixel in the imaging pixel row is discharged to the supply units 35, and the voltage of the photoelectric conversion units 11 is reset. In this way, in parallel with the readout operation of the AF pixel row, a reset operation is performed to discharge the charge in the photoelectric conversion units 11 of each pixel in the imaging pixel row adjacent to the AF pixel row.

[0061] After the charge in the photoelectric conversion unit 11 of each pixel in the imaging pixel row has been discharged, the readout control unit 40 turns off the transfer unit 12 of each pixel in the imaging pixel row. Because the connection unit 15 shared by the pixels in the AF pixel row to be readout and the pixels in the imaging pixel row is on, the voltage of the FD 14 is reset. When the selection unit 17 shared by the pixels in the AF pixel row to be readout and the pixels in the imaging pixel row is on, the dark signal of each pixel in the AF pixel row is output to the vertical signal line 25 connected to that pixel via the selection unit 17 of that pixel.

[0062] After the dark signals of each pixel in the AF pixel row have been read out, the readout control unit 40 turns on the transfer unit 12 of each pixel in the AF pixel row. In each pixel in the AF pixel row, the charge photoelectrically converted by the respective photoelectric conversion unit 11 is transferred to the FD 14. The pixel signal of each pixel in the AF pixel row is output to the vertical signal line 25 connected to that pixel via the selection unit 17 of that pixel.

[0063] As described above, the readout control unit 40 turns on the transfer units 12 of the pixels in the imaging pixel row during the period in which the connection units 15 are turned on to read out the dark signals, and connects the photoelectric conversion units 11 of the pixels in the imaging pixel row to the supply units 35 via the transfer units 12 and the connection units 15. This causes the charge accumulated in the photoelectric conversion units 11 of each pixel in the imaging pixel row to be discharged to the supply units 35, and the voltage of the photoelectric conversion units 11 is reset. In this way, the image sensor 3 according to this embodiment can perform a reset operation on the imaging pixel row adjacent to the AF pixel row even during the period in which the readout operation for that AF pixel row is being performed.

[0064] When discharging the charge accumulated in the photoelectric conversion unit 11a (or 11b), the charge must be discharged to the supply unit 35 via the transfer unit 12a (or 12b), the FD 14, and the connection unit 15. When reading out a pixel signal, the charge photoelectrically converted by the photoelectric conversion unit 11b (or 11a) is transferred to the FD 14 via the transfer unit 12b (or 12a). Therefore, if a reset operation for one of two adjacent pixels sharing the FD 14 and a readout operation for the other pixel are simultaneously performed, the charges generated by the photoelectric conversion units 11a and 11b may be mixed, or the charge transferred from the photoelectric conversion unit 11 of the pixel to be read out to the FD 14 may be discharged to the supply unit 35. This can also be said to result in a collision between the readout operation and the reset operation. In this case, it becomes impossible to properly read out a signal corresponding to the charge photoelectrically converted by the photoelectric conversion unit 11 of the pixel to be read out.

[0065] However, in this embodiment, while the connection unit 15 is turned on to read out the dark signal of one of the two adjacent pixels, the readout control unit 40 turns on the transfer unit 12 of the other pixel to discharge the charge accumulated in the photoelectric conversion unit 11 of the other pixel. This prevents the transfer units 12a and 12b of the two adjacent pixels from both being turned on, thereby preventing them from affecting the charge generated in the photoelectric conversion unit 11 of the pixel to be read out.

[0066] Furthermore, after the charge accumulated in the photoelectric conversion unit 11 of the other pixel is discharged, the readout control unit 40 turns off the transfer unit 12 of the other pixel and then turns off the connection unit 15. In this case, the photoelectric conversion unit 11 and the FD 14 of the other pixel are electrically disconnected, and then the FD 14 is electrically disconnected from the supply unit 35. This reduces the impact of feedthrough on the FD 14 caused by switching the transfer unit 12 and connection unit 15 of the other pixel from an on state to an off state. This suppresses fluctuations in the voltage of the FD 14 due to changes in the signal level of the signal TX input to the transfer unit 12, thereby suppressing noise contamination of the dark signal. Note that the readout control unit 40 does not necessarily have to turn off the connection unit 15 of the other pixel after turning off the transfer unit 12 of the other pixel; it may simultaneously turn off the transfer unit 12 and connection unit 15 of the other pixel.

[0067] In this manner, in this embodiment, even if the readout operation of one pixel and the reset operation of the other pixel among adjacent pixels that share the FD 14 are performed simultaneously, it is possible to prevent degradation of pixel signal quality. The image sensor 3 can avoid collisions between the readout operation and the reset operation, and can appropriately read out signals corresponding to charges photoelectrically converted by the photoelectric conversion unit 11 of the pixel to be read out.

[0068] The image sensor 3 can simultaneously (in parallel) discharge the charge from the FD 14 for reading out the signal from one of two adjacent pixels and discharge the charge accumulated in the photoelectric conversion unit 11 of the other pixel. This allows the image sensor 3 to shorten the time required to read out the pixel signal and discharge the pixel charge compared to when reading out the signal from one pixel and discharging the charge from the other pixel in separate periods, thereby preventing a decrease in the frame rate of shooting.

[0069] FIG. 7 is a timing chart showing an example of the operation of the image sensor 3 during the period enclosed by the dotted line frame G1 in FIG. 6. FIG. 7 shows control signals input to each pixel in an imaging pixel row to be read and to each pixel in an AF pixel row adjacent to that imaging pixel row. In the timing chart shown in FIG. 7, the vertical axis represents the signal voltage level, and the horizontal axis represents time. In FIG. 7, transistors receiving a high-level (e.g., power supply voltage VDD) control signal (signal SEL, signal RST, signal TX) are turned on, and transistors receiving a low-level (e.g., ground voltage) control signal are turned off. Below, an example of the operation of the image sensor 3 during the period enclosed by the dotted line frame G1 in FIG. 6 will be described using the AF pixel 13 in the AF pixel row and the imaging pixel 10 in the imaging pixel row shown in FIG. 3 as examples.

[0070] 7, the signal RST is at a high level, so that the transistor M2 of the connection unit 15 shared by the imaging pixel 10 in the imaging pixel row to be read and the AF pixel 13 in the AF pixel row adjacent to that imaging pixel row is in an on state. At time t11, the signal TX1 goes to a high level, so that the transistor M1a of the transfer unit 12a is in an on state. Because the signals RST and TX1 are both at a high level, the supply unit 35, the FD 14, and the photoelectric conversion unit 11a are electrically connected. As a result, the charge in the photoelectric conversion unit 11a of the AF pixel 13 is discharged, and the voltage of the photoelectric conversion unit 11a is reset.

[0071] At time t12, the signal TX1 goes low, turning off the transistor M1a of the transfer unit 12a. Because the signal RST is high, the charge in the FD 14 shared by the imaging pixel 10 and the AF pixel 13 is reset.

[0072] At time t13, the signal SEL goes high. When the signal SEL goes high, the transistor M4 of the selection unit 17, which is shared by the imaging pixel 10 and the AF pixel 13, goes into the on state. A signal based on the reset voltage of the imaging pixel 10, i.e., a signal (dark signal) obtained after the charge of the FD 14 of the imaging pixel 10 has been reset, is output to the vertical signal line 25 by the amplifier unit 16 and the selection unit 17. The dark signal of the imaging pixel 10 is input to the processing unit 50 via the vertical signal line 25 and converted into a digital signal.

[0073] At time t14, the signal TX2 goes high. When the signal TX2 goes high, the transistor M1b of the transfer unit 12b in the imaging pixel 10 is turned on, electrically connecting the photoelectric conversion unit 11b and the FD14. This causes the charge photoelectrically converted by the photoelectric conversion unit 11b to be transferred to the FD14. Also, because the signal SEL is high, a pixel signal based on the charge generated by the photoelectric conversion unit 11b of the imaging pixel 10 is output to the vertical signal line 25 by the amplifier 16 and the selector 17. The pixel signal of the imaging pixel 10 is input to the processing unit 50 via the vertical signal line 25 and converted into a digital signal. The processing unit 50 performs signal processing such as correlated double sampling using the digitally converted dark signal and the pixel signal, and then outputs the processed signal to the control unit 4.

[0074] Figure 8 is a timing chart showing an example of operation of the image sensor during the period enclosed by the dotted line frame G2 in Figure 6. Figure 8 shows control signals input to each pixel in the AF pixel row to be read out and to each pixel in the imaging pixel row adjacent to that AF pixel row. Below, an example of operation of the image sensor 3 during the period enclosed by the dotted line frame G2 in Figure 6 will be described using the AF pixel 13 in the AF pixel row and the imaging pixel 10 in the imaging pixel row shown in Figure 3 as examples.

[0075] At time t20 shown in Figure 8, signal RST is at a high level, so transistor M2 of connection unit 15 shared by AF pixel 13 in the AF pixel row to be read and imaging pixel 10 in the imaging pixel row adjacent to that AF pixel row is in an on state. At time t21, signal TX2 goes to a high level, so transistor M1b of transfer unit 12b is turned on. Because signals RST and TX2 are both at a high level, supply unit 35, FD 14, and photoelectric conversion unit 11b are electrically connected. This causes the charge in photoelectric conversion unit 11b of imaging pixel 10 to be discharged and the voltage of photoelectric conversion unit 11b to be reset.

[0076] At time t22, the signal TX2 goes low, turning off the transistor M1b of the transfer unit 12b. Because the signal RST is high, the charge in the FD 14 shared by the AF pixel 13 and the imaging pixel 10 is reset.

[0077] At time t23, the signal SEL goes high. When the signal SEL goes high, the transistor M4 of the selection unit 17, which is shared by the AF pixel 13 and the imaging pixel 10, goes into the on state. A signal based on the reset voltage of the AF pixel 13, i.e., a signal (dark signal) obtained after the charge of the FD 14 of the AF pixel 13 has been reset, is output to the vertical signal line 25 by the amplifier unit 16 and the selection unit 17. The dark signal of the AF pixel 13 is input to the processing unit 50 via the vertical signal line 25 and converted into a digital signal.

[0078] At time t24, the signal TX1 goes high. When the signal TX1 goes high, the transistor M1a of the transfer unit 12a in the AF pixel 13 is turned on, electrically connecting the photoelectric conversion unit 11a and the FD 14. This causes the charge photoelectrically converted by the photoelectric conversion unit 11a to be transferred to the FD 14. Furthermore, because the signal SEL is high, a pixel signal based on the charge generated by the photoelectric conversion unit 11a of the AF pixel 13 is output to the vertical signal line 25 by the amplifier 16 and the selector 17. The pixel signal of the AF pixel 13 is input to the processing unit 50 via the vertical signal line 25 and converted into a digital signal. The processing unit 50 performs signal processing such as correlated double sampling using the digitally converted dark signal and the pixel signal, and then outputs the processed signal to the control unit 4.

[0079] As described above, in this embodiment, while the image sensor 3 is discharging charge from the FD 14 to read out a signal from one of two pixels, it can discharge the charge accumulated in the photoelectric conversion unit 11 of the other pixel. This prevents a collision between the readout operation and the reset operation, and suppresses a decrease in the quality of the pixel signal read out by the readout operation. This also prevents a decrease in the accuracy of focus detection using pixel signals.

[0080] According to the above-described embodiment, the following advantageous effects can be obtained: (1) The imaging element 3 includes a first photoelectric conversion unit 11a and a second photoelectric conversion unit 11b that photoelectrically convert light to generate electric charges, an accumulation unit 14 that accumulates the electric charges generated in the first photoelectric conversion unit 11a or the second photoelectric conversion unit 11b, a first transfer unit 12a that transfers the electric charges generated in the first photoelectric conversion unit 11a to the accumulation unit 14, a second transfer unit 12b that transfers the electric charges generated in the second photoelectric conversion unit 11b to the accumulation unit 14, and a supply unit 35 that connects the accumulation unit 14 to a predetermined voltage. The image sensor 3 according to the present embodiment includes a connection unit 15 connectable to the first photoelectric conversion unit 11a and the storage unit 14, a connection unit 15 connects the storage unit 14 and the supply unit 35, and a control unit (readout control unit 40) that performs first control to connect the first photoelectric conversion unit 11a and the storage unit 14 via the first transfer unit 12a, disconnect the first photoelectric conversion unit 11a and the storage unit 14 via the connection unit 15, disconnect the storage unit 14 and the supply unit 35 via the connection unit 15, and connect the second photoelectric conversion unit 11b and the storage unit 14 via the second transfer unit 12b. As a result, the image sensor 3 according to the present embodiment can discharge charges from the photoelectric conversion unit 11a and the FD 14 in parallel, and then read out a signal based on the charges generated by the photoelectric conversion unit 11b. This makes it possible to avoid collisions between the readout operation and the reset operation, thereby suppressing degradation of pixel signal quality.

[0081] (2) In the first control, the control unit disconnects the first photoelectric conversion unit 11a from the storage unit 14, and then disconnects the storage unit 14 from the supply unit 35. This reduces the effect of feedthrough to the FD 14. This makes it possible to prevent noise from being mixed into pixel signals.

[0082] The following modifications are also within the scope of the present invention, and one or more of the modifications may be combined with the above-described embodiment.

[0083] (Variation 1) Fig. 9 is a diagram showing an example of the configuration of a portion of an image sensor according to Modification 1. As shown by dashed lines 20 in Fig. 9, the image sensor 3 according to this modification has a configuration in which two adjacent pixels share the FD 14, the connection unit 15, the amplifier unit 16, and the selection unit 17 (first selection unit 17a, second selection unit 17b).

[0084] The first selection unit 17a is composed of a transistor M4a controlled by a signal SELa, and electrically connects or disconnects the amplifier unit 16 and the first vertical signal line 25a. When the transistor M4a of the first selection unit 17a is in the ON state, it outputs a signal from the amplifier unit 16 to the first vertical signal line 25a. The second selection unit 17b is composed of a transistor M4b controlled by a signal SELb, and electrically connects or disconnects the amplifier unit 16 and the second vertical signal line 25b. When the transistor M4b of the second selection unit 17b is in the ON state, it outputs a signal from the amplifier unit 16 to the second vertical signal line 25b.

[0085] The first current source 26a is connected to each pixel via a first vertical signal line 25a. The first current source 26a generates a current for reading out a signal from the pixel and supplies the generated current to the first vertical signal line 25a and the amplifier unit 16 and first selection unit 17a of each pixel. The second current source 26b is connected to each pixel via a second vertical signal line 25b. The second current source 26b generates a current for reading out a signal from the pixel and supplies the generated current to the second vertical signal line 25b and the amplifier unit 16 and second selection unit 17b of each pixel.

[0086] The readout control unit 40 can output pixel signals to the first vertical signal line 25a by turning on the first selection unit 17a. The readout control unit 40 can also output pixel signals to the second vertical signal line 25b by turning on the second selection unit 17b. The pixel signals output to the first vertical signal line 25a or the second vertical signal line 25b are subjected to signal processing by the processing unit 50 and then output to the control unit 4 of the camera 1.

[0087] The readout control unit 40 may turn on the first selection unit 17a of each pixel in one of the two rows and turn on the second selection unit 17b of each pixel in the other row. In this case, signals from the pixels in one of the two rows are output to the first vertical signal line 25a, and signals from the pixels in the other row are output to the second vertical signal line 25b. This allows the readout control unit 40 to simultaneously read out signals from pixels in two rows and sequentially select pixel rows in pairs to read out pixel signals.

[0088] 9 , the readout control unit 40 may, for example, reset the AF pixel row in the third row and read out the imaging pixel row in the fourth row, and may also read out the imaging pixel row in the fifth row and reset the imaging pixel row in the sixth row. The readout control unit 40 turns on the transfer units 12a of the pixels in the third row while the connection units 15 shared by the pixels in the third and fourth rows are on, and turns on the transfer units 12b of the pixels in the sixth row while the connection units 15 shared by the pixels in the fifth and sixth rows are on. The charges in the photoelectric conversion units 11a of the pixels in the third row are discharged to the supply units 35, and the charges in the photoelectric conversion units 11b of the pixels in the sixth row are discharged to the supply units 35.

[0089] Thereafter, the readout control unit 40 turns off the transfer units 12a of the pixels in the third row and turns off the transfer units 12b of the pixels in the sixth row. Because the connection unit 15 shared by the pixels in the third and fourth rows is on, the voltage of the FD 14 shared by the pixels in the third and fourth rows is reset. Also, because the connection unit 15 shared by the pixels in the fifth and sixth rows is on, the voltage of the FD 14 shared by the pixels in the fifth and sixth rows is reset. The dark signals of the pixels in the fourth row are output to the first vertical signal line 25a via, for example, the first selection unit 17a. The dark signals of the pixels in the fifth row are output to the second vertical signal line 25b via, for example, the second selection unit 17b.

[0090] After the dark signals of the pixels in the fourth and fifth rows have been read out, the readout control unit 40 turns on the transfer units 12b of the pixels in the fourth row and turns on the transfer units 12a of the pixels in the fifth row. In each of the pixels in the fourth and fifth rows, the charges photoelectrically converted by the respective photoelectric conversion units 11 are transferred to the FD 14. The pixel signals of the pixels in the fourth row are output to the first vertical signal line 25a via the first selection unit 17a. The pixel signals of the pixels in the fifth row are output to the second vertical signal line 25b via the second selection unit 17b.

[0091] (Variation 2) In the above-described embodiment, an example has been described in which two adjacent pixels share the FD 14 and the amplifier 16, but the pixel configuration is not limited to this. Three or more pixels may share the FD 14, etc. For example, four pixels may share the FD 14, etc.

[0092] (Variation 3) In the above-described embodiment, an example has been described in which a photodiode is used as the photoelectric conversion unit, but a photoelectric conversion film (organic photoelectric film) may also be used as the photoelectric conversion unit.

[0093] (Variation 4) In the above embodiment, a case has been described in which primary color (RGB) color filters are used in the imaging element 3, but complementary color (CMY) color filters may also be used.

[0094] (Variation 5) 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.

[0095] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0096] 1...imaging device, 3...imaging element, 4a...imaging control unit, 4b...image data generation unit, 10...imaging pixel, 11...photoelectric conversion unit, 12...transfer unit, 13...AF pixel, 14...storage unit, 15...connection unit, 25...vertical signal line, 30, 35...supply unit, 40...readout control unit, 43...light shielding unit

Claims

[Claim 1] a first photoelectric conversion unit that converts light into electric charges; a second photoelectric conversion unit that converts light into electric charges; a first floating diffusion to which the charges converted in the first photoelectric conversion unit and the charges converted in the second photoelectric conversion unit are transferred; a first drain section that has a first transistor for electrically connecting the first floating diffusion and a wiring to which a predetermined voltage is supplied, and that drains charges from the first floating diffusion; a first output unit that outputs to a first signal line: a first signal based on the charge transferred from the second photoelectric conversion unit to the first floating diffusion; and a second signal that is used in first signal processing for the first signal and is based on the charge of the first floating diffusion when the first transistor of the first discharge unit is in an on state, the second signal including a period during which the charge transferred from the first photoelectric conversion unit to the first floating diffusion is discharged by the first discharge unit; a first signal processing unit that performs the first signal processing using a first digital signal obtained by converting the first signal output to the first signal line into a digital signal and a second digital signal obtained by converting the second signal output to the first signal line into a digital signal; An imaging element comprising:

Images