Image sensor

Abstract

This technology provides an improvement in the focus detection accuracy of image sensors. [Solution] The image sensor comprises a microlens, a photoelectric conversion unit that converts light transmitted through the microlens into electric charge, a first photoelectric conversion unit having a first light-receiving area, a second photoelectric conversion unit having a second light-receiving area larger than the first light-receiving area, a third photoelectric conversion unit having a third light-receiving area larger than the first light-receiving area, a first storage unit to which the charge converted by the first photoelectric conversion unit is transferred, a second storage unit to which the charge converted by the second photoelectric conversion unit and the charge converted by the third photoelectric conversion unit are transferred, a first transfer unit, a second transfer unit, a third transfer unit, and a connection unit for electrically connecting the first storage unit and the second storage unit, wherein the second photoelectric conversion unit is positioned further from the optical axis of the microlens than the first photoelectric conversion unit, and the third photoelectric conversion unit is positioned further from the optical axis of the microlens than the first photoelectric conversion unit.

Description

Technical Field

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

Background Art

[0002] An imaging device capable of acquiring a signal used for focus detection by a phase difference detection method is known (for example, Patent Document 1). Conventionally, improvement in focus detection accuracy has been demanded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] According to a first aspect, the imaging device includes a microlens on which light is incident, a photoelectric conversion unit that converts the light transmitted through the microlens into electric charges and has a first light receiving area, a second photoelectric conversion unit that converts the 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 the light transmitted through the microlens into electric charges and has 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, a second accumulation unit to which the electric charges converted by the second photoelectric conversion unit and the electric charges converted by the third photoelectric conversion unit are transferred, a first transfer unit for transferring the electric charges converted by the first photoelectric conversion unit to the first accumulation unit, a second transfer unit for transferring the electric charges converted by the second photoelectric conversion unit to the second accumulation unit, a third transfer unit for transferring the electric charges converted by the third photoelectric conversion unit to the second accumulation unit, and a connection unit for electrically connecting the first accumulation unit and the second accumulation 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. [Brief explanation of the drawing]

[0005] [Figure 1] This figure shows an example of the configuration of an imaging device according to an embodiment. [Figure 2] This figure shows an example of the configuration of an image sensor according to the embodiment. [Figure 3] This figure shows an example of the pixel configuration of an image sensor according to the embodiment. [Figure 4] This is a circuit diagram showing an example of the pixel configuration of an image sensor according to an embodiment. [Figure 5] This is a timing chart illustrating an example of a first readout process performed by an image sensor according to an embodiment. [Figure 6] This is a timing chart illustrating an example of a second readout process by an image sensor according to the embodiment. [Figure 7] This is a timing chart illustrating another example of the second readout process by the image sensor according to the embodiment. [Figure 8] This figure shows an example of the pixel configuration of an image sensor according to Modification Example 1. [Figure 9] This is a timing chart illustrating an example of a second readout process by the image sensor according to Modification 1. [Figure 10] This figure shows an example of the pixel configuration of an image sensor according to Modification 2. [Figure 11] This figure shows an example of the pixel configuration of an image sensor according to Modification 3. [Figure 12] This is a diagram illustrating an example of the pixel configuration of an image sensor related to Modification 4. [Modes for carrying out the invention]

[0006] (Embodiment) Figure 1 shows 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 be a camera in which the camera body 2 and the lens unit 3 are integrally configured.

[0007] 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 provided on the body-side connection unit 202 and multiple terminals provided on the lens-side connection unit 302 are electrically connected. This enables power supply from the camera body 2 to the interchangeable lens 3 and communication between the camera body 2 and the interchangeable lens 3.

[0008] Light from the subject is incident in the positive Z-axis direction in Figure 1. Also, as shown in the coordinate axes of Figure 1, the direction towards the viewer on the paper perpendicular to the Z-axis is the positive X-axis direction, and the direction downwards on the paper perpendicular to both the Z-axis and X-axis is the positive Y-axis direction. In other figures, the coordinate axes may be displayed using the coordinate axes of Figure 1 as a reference to indicate the orientation of each figure.

[0009] The interchangeable lens 3 comprises an optical system 31, a lens control unit 32, and a lens memory 33. The optical system 31 is an imaging optical system (imaging optical system) 31 having a plurality of lenses including a focus lens (focus adjustment lens) and an aperture (aperture diaphragm), and forms an image of the subject on the image sensor 21 of the camera body 2.

[0010] 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 memory such as ROM and RAM. The lens control unit 32 reads and executes programs stored in memory. The lens control unit 32 can also be described as a processing unit (information processing unit) that performs information processing based on the program.

[0011] When the lens control unit 32 receives signals from the camera body 2's body control unit 25 regarding the direction and amount of movement of the focus lens, it moves the focus lens forward and backward in the direction of the optical axis OA1 based on those signals to adjust the focal position of the imaging optical system 31. The lens control unit 32 also controls the aperture diameter based on the signals output from the body control unit 25.

[0012] The lens memory 33 is composed of a non-volatile storage medium or the like. Information related to the interchangeable lens 3 is stored (recorded) in the lens memory 33. The lens memory 33 stores data on the infinity and close positions of the focus lens, data on the shortest and longest focal lengths of the interchangeable lens 3, data on 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.

[0013] Next, an example of the 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 imaging optical system 31 and captures the subject image formed by the imaging optical system 31. The image sensor 21 has a plurality of pixels having photoelectric conversion units arranged in a two-dimensional manner (row direction and column direction). The photoelectric conversion unit is composed of a photodiode (PD) and converts incident light into electric charge. The image sensor 21 generates a signal by photoelectric conversion of the received light and outputs the generated signal to the body control unit 25.

[0014] Memory 22 is composed of a non-volatile storage medium or the like. Memory 22 stores image data, programs and data used to control each part of camera 1, etc. The body control unit 25 writes data to memory 22 and reads data from memory 22.

[0015] 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 the image data stored in the memory 22, an image indicating a focus detection area (AF area) such as an AF frame, information regarding shooting such as shutter speed and aperture value, and a menu screen or the like. 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 an operation by the user and output it to the body control unit 25.

[0016] The operation unit 24 includes members such as a release button, a power button (switch), operation buttons, and switches for switching various modes, and accepts operations on the camera 1. The operation unit 24 detects an operation by the user and outputs a signal based on the operation to the body control unit 25. Note that the operation unit 24 may include the touch panel of the display unit 23.

[0017] The body control unit 25 has a processor and a memory and controls each part of the camera 1. The body control unit 25 has devices such as a CPU, a GPU, an FPGA, an ASIC, etc., and memories such as a ROM and a RAM. The body control unit 25 reads and executes a program stored in the memory. The body control unit 25 can also be said to be a processing unit (information processing unit) that performs information processing based on the program. The body control unit 25 includes an imaging control unit 25a, an image processing unit 25b, and a focus detection unit 25c.

[0018] The imaging control unit 25a supplies a signal for controlling the imaging element 21 to the imaging element 21 and controls the operation of the imaging element 21. When performing still image shooting, video shooting, or displaying a through-image on the display unit 23, etc., the body control unit 25 causes the imaging element 21 to image a subject image and output a signal of pixels. The pixels of the imaging element 21 can output a signal (imaging signal) used for image generation and a signal (focus detection signal) used for focus detection.

[0019] The image processing unit 25b performs various image processing operations on the imaging signal of each pixel output from the image sensor 21 to generate image data (still image data, moving image data) that includes the signal of each pixel. The image processing unit 25b performs image processing such as color interpolation and grayscale conversion. The image processing unit 25b is an image data generation unit that generates image data. The image processing unit 25b may also generate image data using the focus detection signal of the pixels.

[0020] The focus detection unit 25c performs focus detection processing necessary for autofocus (AF) adjustment of the imaging optical system 31. The focus detection unit 25c calculates the amount of defocus using a phase difference detection method with respect to 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 calculation between the focus detection signal generated by capturing an image of a light beam passing through a part of the exit pupil of the imaging optical system 31 and the focus detection signal generated by capturing an image of a light beam passing through another part of the exit pupil. The focus detection unit 25c converts this amount of image shift into a defocus amount based on a predetermined conversion formula.

[0021] The focus detection unit 25c calculates the amount the focus lens should move 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 produced by the imaging optical system 31 is in focus (imaged) on the image sensor 21.

[0022] Figure 2 shows an example of the configuration of an image sensor according to an embodiment. The image sensor 21 has a pixel section (pixel area) 100 in which pixels are arranged in two dimensions (row direction (±X direction) and column direction (±Y direction)), a supply unit 60, a readout control unit 70, and a plurality of processing units 80. In Figure 2, the pixel in the upper left corner is the pixel 10(1,1) of the first row and first column, and the pixel in the lower right corner is the pixel 10(10,6) of the tenth row and sixth column, and a total of 60 pixels in 10 rows and 6 columns are shown. Note that the number and arrangement of pixels on the image sensor 21 are not limited to the example shown.

[0023] In the image sensor 21, a vertical signal line 55 is provided for each of the multiple pixels 10 arranged horizontally (in the 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 vertically (in the column direction). A current source 56 and a processing unit 80 are provided for each of the multiple vertical signal lines 55.

[0024] 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.

[0025] 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 the TX, RST, SEL, and FD_SW signals (described later) to each pixel to control the operation of each pixel. The readout control unit 70 supplies signals to the gates of each transistor of the pixel to set the transistors to an ON state (connected state, conducting state, short circuit state) or an OFF state (disconnected state, non-conducting state, open state, cutoff state). The signal of each pixel is output to the vertical signal line 55 connected to that pixel.

[0026] The current source 56 is connected to each pixel 10 via the vertical signal line 55. The current source 56 generates a current to read signals from the pixels 10 and supplies the generated current to the vertical signal line 55 and each pixel 10.

[0027] The processing unit 80 includes an analog-to-digital conversion unit (AD conversion unit). The processing unit 80 converts the pixel signal, which is an analog signal input from each pixel 10 via the vertical signal line 55, into a digital signal. The processing unit 80 may also have an amplifier unit that amplifies the pixel signal input via the vertical signal line 55 with a predetermined gain (amplification ratio). In this case, the processing unit 80 may convert the pixel signal amplified by the amplifier unit into a digital signal.

[0028] The processing unit 80 outputs the pixel signals, which have been converted into digital signals, to a signal processing unit (not shown). The signal processing unit performs signal processing on the input pixel signals, such as correlated double sampling and signal intensity correction, and then outputs the processed signal to the body control unit 25. Alternatively, the signal processing, such as correlated double sampling, on the pixel signals may be performed in the processing unit 80. In this case, the processing unit 80 may perform signal processing, such as correlated double sampling, on the pixel signals, which have been converted into digital signals, and then output the processed signal to the body control unit 25.

[0029] Figure 3 shows an example of the pixel configuration of an image sensor according to an embodiment. The pixel 10 of the image sensor 21 has a microlens 51, a color filter 52, a light shielding section 53, a first photoelectric conversion section (PD) 11, and a second photoelectric conversion section (PD) 41. The microlens 51 collects light incident from above through the imaging optical system 31 in Figure 3(a). The light shielding section 53 is provided at the boundary between pixels to suppress light leakage into the surrounding area and suppress noise from being mixed into the pixel signal.

[0030] Each pixel 10 is fitted with one of three color filters 52 having different spectral sensitivities, for example, R (red), G (green), and B (blue). The R color filter 52 transmits light in the first wavelength range (red (R) light), the G color filter 52 transmits light in the second wavelength range (green (G) light), and the B color filter 52 transmits light in the third wavelength range (blue (B) light). The image sensor 21 has pixels with an R color filter 52 (R pixels), pixels with a G color filter 52 (G pixels), and pixels with a B color filter 52 (B pixels).

[0031] Furthermore, the image sensor 21 may be provided with pixels 10 having filters that spectrally separate light in the first, second, and third wavelength ranges. Some of the pixels 10 of the plurality of pixels 10 provided on the image sensor 21 do not need to have color filters 52. Alternatively, complementary color filters (CMY) may be provided.

[0032] The first photoelectric conversion unit 11 can generate an electric charge used for image generation. The first photoelectric conversion unit 11 (PD) is formed in the central region of the pixel 10 and, in the example shown in Figure 3, is located on the optical axis OA2 of the microlens 51. The first photoelectric conversion unit 11 receives the light beam that has passed through the exit pupil of the imaging optical system 31 and generates an electric charge by performing photoelectric conversion. The pixel 10 can output a signal based on the electric charge generated by the first photoelectric conversion unit 11, that is, a signal based on the electric charge accumulated by photoelectric conversion of the light beam that has passed through the exit pupil of the imaging optical system 31, as a signal used for image generation (imaging signal). It can also be said that the first photoelectric conversion unit 11 generates an electric charge used for generating signals for images.

[0033] The second photoelectric conversion unit 41 can generate an electric charge 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 arranged 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).

[0034] As shown in Figure 3(b), the second photoelectric conversion unit 41a (PD1L) is positioned in the upper left, the second photoelectric conversion unit 41b (PD1R) in the upper right, the second photoelectric conversion unit 41c (PD2L) in the lower left, and the second photoelectric conversion unit 41d (PD2R) in the lower right. 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 can efficiently receive light that has passed through different regions of the pupil of the imaging optical system 31, and can perform pupil division appropriately.

[0035] The second photoelectric conversion unit 41 receives a light beam that has passed through a portion of the exit pupil region of the imaging optical system 31, performs photoelectric conversion, and generates an electric charge. The pixel 10 can output a signal based on the charge generated by the second photoelectric conversion unit 41, that is, a signal based on the charge accumulated by photoelectric conversion of a light beam that has passed through a portion of the exit pupil region, as a signal used for focus detection (focus detection signal). It can also be said that the second photoelectric conversion unit 41 generates the charge used for generating the signal 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 charges generated by multiple second photoelectric conversion units 41.

[0036] Figure 4 is a circuit diagram showing an example of the pixel configuration of an image sensor according to an embodiment. Pixel 10 includes a first photoelectric conversion unit 11, a first transfer unit 12, a first storage unit 14, a first discharge unit 15, an amplification unit 16, a selection unit 17, and a second discharge unit 18. Pixel 10 also includes a second photoelectric conversion unit 41 (41a to 41d), a second transfer unit 42 (42a to 42d), a second storage unit 44, and a connection unit 45.

[0037] The supply unit 65 is the part of the image sensor 21 that supplies (applies) the power supply voltage VDD to the first output unit 15 and the amplification unit 16 (wiring, electrodes, etc.). The supply unit 66 is the part of the image sensor 21 that supplies the power supply voltage VDD to the second output unit 18. The supply units 65 and 66 are supplied with the power supply voltage VDD from the supply unit 60 (see Figure 2). The supply units 65 and 66 may also be part of the supply unit 60.

[0038] As described above, the pixel 10 is composed of a first photoelectric conversion unit 11 that generates an electric charge used for image generation and second photoelectric conversion units 41a to 41d that generate an electric charge used for focus detection. The first photoelectric conversion unit 11 and the second photoelectric conversion units 41a to 41d are each photodiodes PD, which convert incident light into electric charge and store the photoelectrically converted charge.

[0039] The first transfer unit 12 consists of a transistor M1 controlled by the signal TX_C1, and electrically connects or disconnects the first photoelectric conversion unit 11 and the first storage unit 14. The first transfer unit 12 transfers the charge photoelectrically converted in the first photoelectric conversion unit 11 to the first storage unit 14. Transistor M1 is a transfer transistor.

[0040] The first storage unit 14 is a floating diffusion (FD). The capacitance C1 of the first storage unit 14 is the capacitance that stores (holds) the charge transferred to the first storage unit 14. The first storage unit 14 can store the charge generated in the first photoelectric conversion unit 11 and the second photoelectric conversion units 41a to 41d.

[0041] The amplification unit 16 consists of a transistor M3 whose gate (terminal) is connected to the first storage unit 14. The amplification unit 16 amplifies and outputs the signal based on the charge transferred from the first photoelectric conversion unit 11 and the second photoelectric conversion units 41a to 41d. The drain (terminal) and source (terminal) of transistor M3 are connected to the supply unit 65 and the selection unit 17, respectively, which supply the power supply voltage VDD. The source of the amplification unit 16 is connected to the vertical signal line 55 via the selection unit 17. Transistor M3 is an amplification transistor. The amplification 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.

[0042] The first discharge unit 15 consists of a transistor M2 controlled by the signal RST. The first discharge unit 15 is a connection unit 15 that electrically connects or disconnects the supply unit 65 and the first storage unit 14. By connecting the supply unit 65 and the first storage unit 14, the first discharge unit 15 discharges the charge stored in the first storage unit 14 to the supply unit 65. The first discharge unit 15 can also discharge the charge stored in the second storage unit 44 to the supply unit 65 via the connection unit 45. The first discharge unit (reset unit) 15 discharges the charge stored in the first storage unit 14 and the second storage unit 44 and resets the voltage between the first storage unit 14 and the second storage unit 44. Transistor M2 is a reset transistor.

[0043] The selection unit 17 consists of a transistor M4 controlled by the signal SEL, and electrically connects or disconnects the amplifier unit 16 and the vertical signal line 55. When the transistor M4 of the selection unit 17 is ON, it outputs the signal from the amplifier unit 16 to the vertical signal line 55. Transistor M4 is a selection transistor.

[0044] The second discharge unit 18 consists of a transistor M5 controlled by the 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. By connecting the supply unit 66 and the first photoelectric conversion unit 11, the second discharge unit 18 discharges 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 called a reset transistor.

[0045] The second transfer unit 42a is composed of a transistor M6a controlled by the signal TX_1L, and electrically connects or disconnects the second photoelectric conversion unit 41a and the second storage unit 44. The second transfer unit 42b is composed of a transistor M6b controlled by the signal TX_1R, and electrically connects or disconnects the second photoelectric conversion unit 41b and the second storage unit 44. The second transfer unit 42c is composed of a transistor M6c controlled by the signal TX_2L, and electrically connects or disconnects the second photoelectric conversion unit 41c and the second storage unit 44. Furthermore, the second transfer unit 42d is composed of a transistor M6d controlled by the signal TX_2R, and electrically connects or disconnects the second photoelectric conversion unit 41d and the second storage unit 44.

[0046] The second transfer units 42a to 42d each transfer the charge converted photoelectrically by the second photoelectric conversion units 41a to 41d to the second storage unit 44. Transistors M6a to M6d are each transfer transistors. Capacitors C2a to C2d of the second storage unit 44 are capacitors that store (hold) the charge transferred to the second storage unit 44. The second storage unit 44 stores the charge generated by the second photoelectric conversion units 41a to 41d.

[0047] The connection section 45 is composed of a transistor M7 controlled by the signal FD_SW, and electrically connects or disconnects the first storage section 14 and the second storage section 44. By connecting the first storage section 14 and the second storage section 44, the connection section 45 makes it possible to transfer the charge of the second storage section 44 to the first storage section 14. It should also be said that the connection section 45, the first discharge section (connection section) 15 and the second discharge section (connection section) 18 described above are switching sections (switches) that switch between connecting and disconnecting, respectively.

[0048] The readout control unit 70 (see Figure 2) controls signals TX, SEL, FD_SW, etc., input to each pixel 10, thereby reading out signals based on the charge generated by the first photoelectric conversion unit 11 and signals based on the charge generated by the second photoelectric conversion unit 41. When the transistor M7 of the connection unit 45 is turned off, the first storage unit 14 and the second storage unit 44 are electrically disconnected. In this case, the charge transferred from the first photoelectric conversion unit 11 by the first transfer unit 12 is stored in the first storage unit 14. The amplification unit 16 and the selection unit 17 can output a signal (imaging signal) corresponding to the charge stored in the first storage unit 14 to the vertical signal line 55.

[0049] When the transistor M7 of the connection unit 45 is turned ON, the first storage unit 14 and the second storage 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 stored in the second storage unit 44 and the first storage unit 14. The amplification unit 16 and the selection unit 17 can output a signal (focus detection signal) corresponding to the charge stored in the first storage unit 14 and the second storage unit 44 to the vertical signal line 55.

[0050] Thus, in the image sensor 21 according to this embodiment, it is possible to obtain an imaging signal used for image generation and a focus detection signal used for focus detection for each pixel. Furthermore, in this embodiment, a first storage unit 14, a first discharge unit 15, an amplification unit 16, and a selection unit 17 are provided in common to the first photoelectric conversion unit 11 of the pixel 10 and the plurality of second photoelectric conversion units 41. Compared to the case in which the amplification unit 16, selection unit 17, etc. are provided separately for the first photoelectric conversion unit 11 and the second photoelectric conversion units 41, the circuit area for each pixel 10 can be reduced. This makes it possible to suppress an increase in the chip area of ​​the image sensor 21 and an increase in manufacturing costs.

[0051] Furthermore, the imaging control unit 25a according to this embodiment can control the readout control unit 70 to perform a process of individually reading out signals based on the charge generated in each of the multiple second photoelectric conversion units 41 of the image sensor 21 (first readout process), and a process of reading out a signal based on the charge obtained by adding up the charges generated in each of the multiple second photoelectric conversion units 41 (second readout process). Below, an example of a method for reading signals from pixels will be described with reference to the drawings.

[0052] Figure 5 is a timing chart illustrating an example of a first readout process by an image sensor according to the embodiment. In Figure 5, the control signals input to the pixels and the signals output from the pixels and sampled are schematically shown on the same time axis. In Figure 5, transistors that receive high-level control signals (e.g., power supply voltage VDD) (e.g., signals RST, TX, SEL, FD_SW, etc.) are turned ON, and transistors that receive low-level control signals (e.g., ground voltage) are turned OFF.

[0053] At time t1 shown in Figure 5, the signal FD_SW becomes high level. When the signal FD_SW becomes high level, the transistor M7 of the connection part 45 turns on, and the first storage part 14 and the second storage part 44 are electrically connected. Also at time t1, the signal TX_C2 becomes high level. When the signal TX_C2 becomes high level, the transistor M5 of the second discharge part 18 in the pixel 10 turns on, and the first photoelectric conversion part 11 and the supply part 66 are electrically connected. As a result, the charge of the first photoelectric conversion part 11 is discharged to the supply part 66, and the voltage of the first photoelectric conversion part 11 is reset. The first photoelectric conversion part 11 is in a reset state, and it is possible to suppress the leakage of charge from the first photoelectric conversion part 11 due to charge saturation to other photoelectric conversion parts and storage parts, etc. This can suppress the mixing of noise into the pixel signal.

[0054] Furthermore, at time t1, the signal RST becomes high level. When the signal RST becomes high level, the transistor M2 of the first discharge unit 15 turns on, and the first storage unit 14 and the supply unit 65 are electrically connected. 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 charge in the first storage unit 14 and the second storage unit 44 is reset, and the voltages in the first storage unit 14 and the second storage unit 44 become the reset voltage.

[0055] Furthermore, at time t1, the signal SEL becomes high level. When the signal SEL becomes high level, the transistor M4 of the selection unit 17 turns on. As a result, the signal based on the reset voltage of the pixel 10, that is, the signal after the charge of the first storage unit 14 and the second storage unit 44 of the pixel 10 has been reset, is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal based on the reset voltage is input to the processing unit 80 via the vertical signal line 55 as a reset signal (dark signal) Rst1L and is sampled. The reset signal Rst1L is converted into a digital signal by the processing unit 80.

[0056] At time t2, the signal TX_1L becomes high level. When the signal TX_1L becomes high level, the transistor M6a of the second transfer unit 42a in pixel 10 turns on, and the second photoelectric conversion unit 41a and the second storage unit 44 are electrically connected. The second storage unit 44 is also electrically connected to the first storage unit 14 via the connection unit 45. Therefore, the charge photoelectrically converted in the second photoelectric conversion unit 41a is transferred to the second storage unit 44 and the first storage unit 14.

[0057] Furthermore, at time t2, since the signal SEL is at a high level, the 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 amplification unit 16 and the selection unit 17. The signal based on the charge generated by the second photoelectric conversion unit 41a is output to the processing unit 80 via the vertical signal line 55 as the pixel signal Sig1L and sampled. The pixel signal Sig1L is converted into a digital signal by the processing unit 80.

[0058] At time t3, the signal RST becomes high level, which turns on transistor M2 of the first discharge unit 15, resetting the charge 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. Because the signal SEL is high level, a signal based on the reset voltage is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal based on the reset voltage is input to the processing unit 80 via the vertical signal line 55 as the reset signal Rst1R, and is converted into a digital signal.

[0059] At time t4, the signal TX_1R becomes high level, which turns on transistor M6b of the second transfer unit 42b, electrically connecting the second photoelectric conversion unit 41b and the second storage unit 44. As a result, the charge photoelectrically converted in the second photoelectric conversion unit 41b is transferred to the second storage unit 44 and the first storage unit 14. Also, because the signal SEL is high level, the signal based on the charge generated in the second photoelectric conversion unit 41b is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal based on the charge generated in the second photoelectric conversion unit 41b is input to the processing unit 80 via the vertical signal line 55 as the pixel signal Sig1R and converted into a digital signal.

[0060] At time t5, the signal RST becomes high level, which turns on transistor M2 of the first output unit 15, and the voltages of the first storage unit 14 and the second storage unit 44 become the reset voltage. The signal Rst2L based on the reset voltage is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0061] At time t6, the signal TX_2L becomes high level, which turns on the transistor M6c of the second transfer unit 42c, and the charge photoelectrically converted in the second photoelectric conversion unit 41c is transferred to the second storage unit 44 and the first storage unit 14. The signal Sig2L, based on the charge generated in the second photoelectric conversion unit 41c, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0062] At time t7, the signal RST becomes high level, causing the voltages of the first storage unit 14 and the second storage unit 44 to become the reset voltage. The signal Rst2R, based on the reset voltage, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0063] At time t8, the signal TX_2R becomes high level, which turns on the transistor M6d of the second transfer unit 42d, and the charge photoelectrically converted in the second photoelectric conversion unit 41d is transferred to the second storage unit 44 and the first storage unit 14. The signal Sig2R, based on the charge generated in the second photoelectric conversion unit 41d, is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The pixel signal Sig2R is input to the processing unit 80 via the vertical signal line 55 and converted into a digital signal.

[0064] At time t9, the signal FD_SW goes low, and transistor M7 of the connection section 45 turns off. Also at time t9, the signal TX_C2 goes low, and transistor M5 of the second output section 18 turns off. Furthermore, the signal SEL goes low, and transistor M4 of the selection section 17 turns off.

[0065] At time t10, the signal RST becomes high, and the voltage of the first storage unit 14 becomes the reset voltage. Also at time t10, the signal SEL becomes high. When the signal SEL becomes high, the signal based on the reset voltage is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal based on the reset voltage is input to the processing unit 80 via the vertical signal line 55 as the reset signal RstC, and is converted into a digital signal.

[0066] At time t11, the signal TX_C1 becomes high level, which turns on the transistor M1 of the first transfer unit 12, and the charge photoelectrically converted in the first photoelectric conversion unit 11 is transferred to the first storage unit 14. Because the signal SEL is high level, the signal based on the charge generated in the first photoelectric conversion unit 11 is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal based on the charge generated in the first photoelectric conversion unit 11 is input to the processing unit 80 via the vertical signal line 55 as the pixel signal SigC, and is converted into a digital signal.

[0067] The processing unit 80 performs correlated double sampling (CDS) using the reset signal and pixel signal, which have been converted into digital signals. For example, the processing unit 80 performs CDS processing such as difference processing between signal Rst1L and signal Sig1L, difference processing between signal Rst1R and signal Sig1R, difference processing between signal Rst2L and signal Sig2L, difference processing between signal Rst2R and signal Sig2R, and difference processing between signal RstC and signal SigC. After performing signal processing such as CDS processing, the processing unit 80 outputs the processed signal to the body control unit 25 as the imaging signal and focus detection signal.

[0068] In this way, the readout control unit 70 of the image sensor 21 can read out the imaging signal (signal SigC) used for image generation and the focus detection signals (signals Sig1L, Sig1R, Sig2L, Sig2R) used for focus detection by controlling the connection unit 45. It becomes possible to obtain both the imaging signal and the focus detection signal for each pixel 10.

[0069] Figure 6 is a timing chart illustrating an example of a second readout process by the image sensor according to the embodiment. At time t21 shown in Figure 6, when the signal FD_SW becomes high level, the transistor M7 of the connection unit 45 turns on, and the first storage unit 14 and the second storage unit 44 are electrically connected. Also, when the signal TX_C2 becomes high level, the transistor M5 of the second discharge unit 18 turns on, and the first photoelectric conversion unit 11 and the supply unit 66 are electrically connected.

[0070] Furthermore, at time t21, the signal RST becomes high level, which turns on transistor M2 of the first discharge unit 15, resetting the charge 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, when the signal SEL becomes high level, the signal Rst based on the reset voltage is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0071] At time t22, the signal TX_1L becomes high level, which turns on transistor M6a of the second transfer unit 42a, electrically connecting the second photoelectric conversion unit 41a and the second storage unit 44. As a result, the charge photoelectrically converted in the second photoelectric conversion unit 41a is transferred to the second storage unit 44 and the first storage unit 14. Also, because the signal SEL is high level, the signal Sig1L, based on the charge generated in the second photoelectric conversion unit 41a, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0072] At time t23, the signal TX_1R becomes high level, which turns on transistor M6b of the second transfer unit 42b, electrically connecting the second photoelectric conversion unit 41b and the second storage unit 44. The charge photoelectrically converted in the second photoelectric conversion unit 41b is transferred to the second storage unit 44 and the first storage unit 14. In this case, the charge transferred from the second photoelectric conversion unit 41a and the charge transferred from the second photoelectric conversion unit 41b, which are stored in the second storage unit 44 and the first storage unit 14, are added together. It can also be said that the charges generated in the second photoelectric conversion unit 41a and the second photoelectric conversion unit 41b are mixed.

[0073] Furthermore, at time t23, since the signal SEL is at a high level, the signal Sig1L+1R, based on the charge 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 amplification unit 16 and the selection 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.

[0074] At time t24, the signal TX_2L becomes high level, which turns on the transistor M6c of the second transfer unit 42c, electrically connecting the second photoelectric conversion unit 41c and the second storage unit 44. The charge photoelectrically converted in the second photoelectric conversion unit 41c is transferred to the second storage unit 44 and the first storage unit 14. As a result, the charges generated in each of the second photoelectric conversion units 41a to 41c are added together in the second storage unit 44 and the first storage unit 14. Because the signal SEL is high level, the signal Sig1L+1R+2L, based on the charges generated in the second photoelectric conversion units 41a to 41c, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0075] At time t25, the signal TX_2R becomes high level, which turns on the transistor M6d of the second transfer unit 42d, electrically connecting the second photoelectric conversion unit 41d and the second storage unit 44. In the second storage unit 44 and the first storage unit 14, the charges generated in each of the second photoelectric conversion units 41a to 41d are added together. Because the signal SEL is high level, the 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 amplification unit 16 and the selection 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, the signals FD_SW, TX_C2, and SEL are all set to low levels.

[0076] At time t27, the signal RST becomes high, causing the voltage of the first storage unit 14 to become the reset voltage. Also, when the signal SEL becomes high, the signal RstC, based on the reset voltage, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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, when the signal TX_C1 becomes high, the transistor M1 of the first transfer unit 12 turns on, and the charge photoelectrically converted in the first photoelectric conversion unit 11 is transferred to the first storage unit 14. The signal SigC, based on the charge generated in the first photoelectric conversion unit 11, is output to the vertical signal line 55 by the amplification unit 16 and the selection 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.

[0077] The processing unit 80 performs signal processing such as CDS processing using the reset signal and pixel signal converted to digital signals, and then outputs the processed signal to the body control unit 25. The signals Sig1R, Sig2L, and Sig2R can be obtained by performing subtraction processing between the pixel signals (Sig1L, Sig1L+1R, Sig1L+1R+2L, Sig1L+1R+2L+2R).

[0078] Figure 7 is a timing chart illustrating another example of the second readout process by the image sensor according to the embodiment. At time t31 shown in Figure 7, the signal FD_SW becomes high, and the first storage unit 14 and the second storage unit 44 are electrically connected. Also, the signal TX_C2 becomes high, and the first photoelectric conversion unit 11 and the supply unit 66 are electrically connected.

[0079] Furthermore, at time t31, the signal RST becomes high level, and the voltages of the first storage unit 14 and the second storage unit 44 become the reset voltage. As the signal SEL becomes high level, the signal RstL, based on the reset voltage, is output to the vertical signal line 55 by the amplification unit 16 and the selection unit 17. The signal RstL is input to the processing unit 80 via the vertical signal line 55, sampled, and converted into a digital signal.

[0080] At time t32, signals TX_1L and TX_2L become high levels, electrically connecting the second photoelectric conversion unit 41a, the second photoelectric conversion unit 41c, and the second storage unit 44. In the second storage unit 44 and the first storage unit 14, the charge transferred from the second photoelectric conversion unit 41a and the charge transferred from the second photoelectric conversion unit 41c are added together. Because signal SEL is high level, the 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.

[0081] At time t33, the signal RST becomes high level, and the voltages of the first storage unit 14 and the second storage unit 44 become the reset voltage. The 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.

[0082] At time t34, signals TX_1R and TX_2R become high levels, electrically connecting the second photoelectric conversion unit 41b, the second photoelectric conversion unit 41d, and the second storage unit 44. In the second storage unit 44 and the first storage unit 14, the charge transferred from the second photoelectric conversion unit 41b and the charge transferred from the second photoelectric conversion unit 41d are added together. Because signal SEL is high level, 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 are all set to low levels.

[0083] During the period from time t36 to time t38 shown in Figure 7, the reset signal RstC and the 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.

[0084] In the example described above, the case where the signal Sig1L+2L based on the charge generated by the second photoelectric conversion units 41a and 41c and the signal Sig1R+2R based on the charge generated by the second photoelectric conversion units 41b and 41d are read out was explained. However, it is also possible to read out the signal Sig1L+1R based on the charge generated by the second photoelectric conversion units 41a and 41b and the signal Sig2L+2R based on the charge generated by the second photoelectric conversion units 41c and 41d.

[0085] As explained with reference to 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 the charges generated by the multiple second photoelectric conversion units 41. In the case of the second readout process, the time required to read out the pixel signal can be shortened compared to the case of the first readout process in Figure 5. This makes it possible to read out the focus detection signal at high speed.

[0086] 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 converts light transmitted through the microlens 51 into electric charge, a second photoelectric conversion unit and a third photoelectric conversion unit (for example, second photoelectric conversion units 41a, 41b) that convert light transmitted through the microlens 51 into electric charge, a first storage unit (first storage unit 14) that stores the charge generated in the first photoelectric conversion unit, and a third storage unit that transfers the charge generated in the first photoelectric conversion unit to the first storage unit. The system includes a first transfer unit (first transfer unit 12), a second storage unit (second storage unit 44) that stores 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 42a) that transfers the charge generated by the second photoelectric conversion unit to the second storage unit, a third transfer unit (second transfer unit 42b) that transfers the charge generated by the third photoelectric conversion unit to the second storage unit, and a connection unit (connection unit 45) that can connect the first storage unit and the second storage unit. In this embodiment, a plurality of second photoelectric conversion units 41 and second transfer units 42 are electrically connected to the first storage unit 14 (FD) via the connection unit 45. The charge photoelectrically converted by the second photoelectric conversion unit 41 is transferred to the FD 14, and the focus detection signal can be read out.

[0087] (2) In this embodiment, by controlling the connection unit 45, it is possible to read out the imaging signal and the focus detection signal from each pixel 10. In this embodiment, compared to the case in which circuits for reading signals separately are provided for the first photoelectric conversion unit 11 and the second photoelectric conversion unit 41, the number of elements per pixel 10 can be reduced. Therefore, an increase in chip area can be suppressed.

[0088] The following modifications are also within the scope of the present invention, and it is possible to combine one or more of these modifications with the embodiments described above.

[0089] (Variation 1) Figure 8 shows an example of the pixel configuration of an image sensor according to Modification 1. The pixel 10 according to this modification has a third discharge section 46 (46a to 46d). The supply section 67 is the part that supplies the power supply voltage VDD to the third discharge section 46, and the power supply voltage VDD is supplied from the supply section 60. Note that the supply section 67 may be part of the supply section 60.

[0090] The third discharge section 46a to 46d consists of transistors M8a to M8d controlled by signals TX_1L_2 to TX_2R_2, as shown in Figure 8. The third discharge section 46a to 46d is a connection section 46a to 46d that electrically connects or disconnects the second photoelectric conversion section 41a to 41d and the supply section 67. The third discharge section (connection section) 46 can also be called a switching section (switch section) that switches between connection and disconnection. The third discharge section 46 discharges the charge accumulated in the second photoelectric conversion section 41 to the supply section 67 by connecting the supply section 67 and the second photoelectric conversion section 41. The third discharge section (reset section) 46 discharges the charge accumulated in the second photoelectric conversion section 41 and resets the voltage of the second photoelectric conversion section 41. Transistor M8 can also be called a reset transistor. In the following description, we will mainly describe operations that differ from the operation of the embodiment described above.

[0091] Figure 9 is a timing chart illustrating an example of the second readout process by the image sensor according to Modification 1. In the example shown in Figure 9, during the period from time t41 to time t43 when the reset signal RstL and the pixel signal Sig1L+2L are read out, the signals TX_1R_2 and TX_2R_2 are at a high level. When the signal TX_1R_2 is at a high level, the transistor M8b of the third output unit 46b is turned on, and the second photoelectric conversion unit 41b and the supply unit 67 are electrically connected. Also, when the signal TX_2R_2 is at a high level, the transistor M8d of the third output unit 46d is turned on, and the second photoelectric conversion unit 41d and the supply unit 67 are electrically connected.

[0092] During the period from time t43 to time t45, when the reset signal RstR and the pixel signal Sig1R+2R are read out, signals TX_1L_2 and TX_2L_2 are both at a high level. When signal TX_1L_2 is at a high level, transistor M8a of the third output unit 46a is turned on, and the second photoelectric conversion unit 41a and the supply unit 67 are electrically connected. When signal TX_2L_2 is at a high level, transistor M8c of the third output unit 46c is turned on, and the second photoelectric conversion unit 41c and the supply unit 67 are electrically connected.

[0093] Thus, 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, and it is possible to suppress the leakage of charge from the second photoelectric conversion unit 41 due to charge saturation to other photoelectric conversion units and storage units. This also suppresses the introduction of noise into the pixel signal.

[0094] (Modification 2) Figure 10 shows an example of the pixel configuration of an image sensor according to Modification 2. In the example shown in Figure 10(a), a light-shielding portion 54 is provided so as to cover the periphery of each of the first photoelectric conversion unit 11 and the plurality of second photoelectric conversion units 41. The light-shielding portion (light-shielding film) 54 is made of a conductive 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 so as to cover the region (Tr region) where transistors such as the amplification unit 16 and selection unit 17 that constitute the pixel 10 are arranged. The light-shielding portion 54 can suppress light from entering the Tr region and suppress noise from being mixed into the pixel signal. Note that, as shown in Figure 10(b), a light-shielding portion 54a may be provided to cover the periphery of the first photoelectric conversion unit 11, and a light-shielding portion 54b may be provided to cover the periphery of the second photoelectric conversion units 41a to 41d.

[0095] (Variation 3) As shown in Figure 11, insulating sections 58 may be provided around the first photoelectric conversion unit 11 and the plurality of second photoelectric conversion units 41. The insulating section 58 is an insulating layer made of an insulating material and is composed of DTI (Deep Trench Isolation). As shown in Figures 11(a) and (b), insulating sections 58a and 58b may be provided so as to surround each of the first photoelectric conversion unit 11 and the plurality of second photoelectric conversion units 41. The insulating section 58 separates the photoelectric conversion units and can suppress the leakage of charge generated in one photoelectric conversion unit to other photoelectric conversion units. Furthermore, as shown in Figure 11(c), insulating section 58c may be provided so as to surround the first photoelectric conversion unit 11, and insulating section 58d may be provided so as to surround the second photoelectric conversion units 41a to 41d.

[0096] (Modification 4) In the embodiments and modified examples described above, examples of the configuration of the pixel 10 have been explained, but these are merely examples and are not limited to those described above. For example, the number and arrangement of the second photoelectric conversion units 41 are not limited to those described above. The configuration of the pixel 10 may have two or three second photoelectric conversion units 41, or it may have five or more second photoelectric conversion units 41. For example, the configuration of the pixel 10 may have one first photoelectric conversion unit 11 and two second photoelectric conversion units 41 from four second photoelectric conversion units 41a to 41d (PD1L, PD1R, PD2L, PD2R). Also, for example, as shown in Figure 12(a), eight second photoelectric conversion units 41 may be arranged per pixel.

[0097] As shown in Figures 12(b) and (c), a microlens 51 may be provided for each photoelectric conversion unit. In the example shown in Figure 12(c), a total of six pixels 10 are illustrated. A light-shielding section 56 may be provided between the second photoelectric conversion unit 41 and the microlens 51b in the Z-axis direction to block a portion of the light incident on the second photoelectric conversion unit 41. Each light-shielding section 56 provided for each second photoelectric conversion unit 41 may be arranged so that light that has passed through different regions of the exit pupil of the imaging optical system 31 is incident on the second photoelectric conversion unit 41.

[0098] 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, respectively. The height of microlens 51b may be greater than the height of microlens 51a so that the incident light is focused to 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.

[0099] (Variation 5) In the embodiments and modifications described above, examples were given in which a photodiode is used as the photoelectric conversion unit. However, a photoelectric conversion film (organic photoelectric film) may also be used as the photoelectric conversion unit.

[0100] (Experimental variation 6) The image sensor and imaging device described in the above embodiments and modifications 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.).

[0101] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments 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]

[0102] 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

[Claim 1] A microlens into which light is incident, A photoelectric conversion unit that converts light transmitted through the microlens into an electric charge, comprising a first photoelectric conversion unit having a first light-receiving area, A photoelectric conversion unit that converts light transmitted through the microlens into electric charge, comprising a second photoelectric conversion unit having a second light-receiving area larger than the first light-receiving area, A photoelectric conversion unit that converts light transmitted through the microlens into electric charge, comprising a third photoelectric conversion unit having a third light-receiving area larger than the first light-receiving area, A first storage unit to which the charge converted in the first photoelectric conversion unit is transferred, A second storage unit to which the charge converted in the second photoelectric conversion unit and the charge converted in the third photoelectric conversion unit are transferred, A first transfer unit for transferring the charge converted by the first photoelectric conversion unit to the first storage unit, A second transfer unit for transferring the charge converted by the second photoelectric conversion unit to the second storage unit, A third transfer unit for transferring the charge converted in the third photoelectric conversion unit to the second storage unit, A connection part for electrically connecting the first storage unit and the second storage unit Equipped with, The second photoelectric conversion unit is positioned further away from the optical axis of the microlens than the first photoelectric conversion unit. The third photoelectric conversion unit is positioned further away from the optical axis of the microlens than the first photoelectric conversion unit. Image sensor.

Images