Imaging element and imaging device
By introducing a photoelectric conversion unit, a comparison unit and a storage unit into the imaging element, and using the switch control of the reading control unit, the problem of low signal reading efficiency of the existing imaging element is solved, and more efficient signal reading and faster frame rates are achieved.
Patent Information
- Application Number
- CN202510446691.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2019-03-29
- Filing Date
- 2020-03-27
- Publication Date
- 2025-05-30
AI Technical Summary
The existing imaging elements have problems of inefficiency in signal processing and horizontal transmission control, especially in the readout process of multiple pixel signals.
The imaging element structure with the first and second photoelectric conversion units, the comparison units and the storage units is adopted, and the switches SW1 and SW2 are controlled by the readout control unit to realize different reading methods (such as individual readings, additive readings, etc.) to improve signal reading efficiency.
By optimizing the readout processing method, the readout time of pixel signals is shortened, the frame rate during imaging is increased, and the area of the imaging element is avoided.
Smart Images

Figure CN120075635A_ABST
Abstract
Description
[0001] This divisional application is a divisional application of an invention application with an international filing date of March 27, 2020, an international application number of PCT / JP2020 / 014103, a national application number entered into the Chinese national phase of 202080031798.X, and an invention title of "Imaging Element and Imaging Device". Technical Field
[0002] The present invention relates to an imaging element and an imaging device. Background Art
[0003] Hitherto, an imaging element having a storage unit that stores a digital value corresponding to the amount of light received by a pixel, and a storage unit that temporarily stores the digital value for signal processing or horizontal transfer control has been known (for example, Patent Document 1).
[0004] Prior Art Documents
[0005] Patent Documents
[0006] Patent Document 1: WO 2017 / 18215 Summary of the Invention
[0007] According to a first aspect of the invention, an imaging element includes: a first photoelectric conversion unit and a second photoelectric conversion unit that generate charges by photoelectric conversion; a first comparison unit that outputs a first signal based on a first comparison result, the first comparison result being a result of comparing a signal based on the charge generated by the first photoelectric conversion unit with a reference signal; a first storage unit that receives the first signal output from the first comparison unit and stores a signal based on the first signal; a second comparison unit that outputs a second signal based on a second comparison result, the second comparison result being a result of comparing a signal based on the charge generated by the second photoelectric conversion unit with the reference signal; a second storage unit that receives the second signal output from the second comparison unit and stores a signal based on the second signal; and a first connection unit that can connect or disconnect the first comparison unit and the second storage unit.
[0008] According to a second aspect of the invention, an imaging device includes: an imaging element according to the first aspect; a generation unit that generates image data based on a signal output from the imaging element. Brief Description of the Drawings
[0009] Figure 1 It is a diagram showing a configuration example of the imaging device according to the first embodiment.
[0010] Figure 2 It is a block diagram showing a configuration example of the imaging element according to the first embodiment.
[0011] Figure 3 This is a circuit diagram showing a configuration example of a part of the imaging element according to the first embodiment.
[0012] Figure 4 This is a diagram for explaining the readout process of the imaging element according to the first embodiment.
[0013] Figure 5 This is a diagram showing an example of a method for adding signals of pixels in the imaging element according to the first embodiment.
[0014] Figure 6 This is a diagram for explaining another readout process of the imaging element according to the first embodiment.
[0015] Figure 7 This is a diagram for explaining another readout process of the imaging element according to the first embodiment.
[0016] Figure 8 This is a diagram for explaining another readout process of the imaging element according to the first embodiment.
[0017] Figure 9 This is a diagram for explaining another readout process of the imaging element according to the first embodiment.
[0018] Figure 10 This is a diagram for comparing the readout processes of the imaging element according to the first embodiment. Detailed implementation manners
[0019] (First embodiment)
[0020] Figure 1 This is a diagram showing a configuration example of an example of the imaging device according to the first embodiment, i.e., the camera 1. The camera 1 includes a photographic optical system (imaging optical system) 2, an imaging element 3, a control unit 4, a memory 5, a display unit 6, and an operation unit 7. The photographic optical system 2 includes a plurality of lenses including a focus adjustment lens (focusing lens) and an aperture stop, and forms an object image on the imaging element 3. In addition, the photographic optical system 2 may be configured to be detachable from the camera 1.
[0021] The imaging element 3 is an imaging element such as a CMOS image sensor or a CCD image sensor. The imaging element 3 receives the light beam passing through the photographic optical system 2 and captures the object image formed by the photographic optical system 2. In the imaging element 3, a plurality of pixels having a photoelectric conversion unit are arranged two-dimensionally (in the row direction and the column direction). The photoelectric conversion element is composed of a photodiode (PD). The imaging element 3 performs photoelectric conversion on the received light to generate a signal, and outputs the generated signal to the control unit 4.
[0022] 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 photography 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 a switch for switching various modes, and outputs signals based on respective operations to the control unit 4.
[0023] The control unit 4 is composed of a processor such as a CPU, FPGA, ASIC, etc., and memories such as a ROM and a RAM, and controls each part of the camera 1 based on a control program. The control unit 4 supplies a signal for controlling the imaging element 3 to the imaging element 3 to control the operation of the imaging element 3. In addition, the control unit 4 performs various image processes on the signal output from the imaging element 3 to generate image data. The control unit 4 is also an image generation unit for generating image data, and generates still image data and moving image data based on the signal output from the imaging element 3. The image process includes image processes such as grayscale conversion processing and color interpolation.
[0024] The control unit 4 performs a process of individually reading signals of all pixels of the imaging element 3 and a process of reading by mixing (adding) signals of multiple pixels. The control unit 4 controls the imaging element 3 to select (set) a method for reading signals of pixels. For example, when the control unit 4 displays a live view image (real-time view image) of a subject on the display unit 6 and when performing moving image photography, it performs a process of mixing and reading signals of multiple pixels. In addition, when performing high-resolution still image photography, the control unit 4 performs a process of individually reading signals of all pixels.
[0025] Figure 2 It is a block diagram showing a configuration example of the imaging element of the first embodiment. The imaging element 3 is constituted by laminating a first substrate 111 having a plurality of pixels 10 arranged two-dimensionally and a second substrate 112 having a plurality of analog / digital conversion units (AD conversion units) 40. The first substrate 111 and the second substrate 112 are each constituted by using a semiconductor substrate. The circuit provided on the first substrate 111 and the circuit provided on the second substrate 112 are electrically connected by bumps, electrodes, etc.
[0026] The first substrate 111 has a plurality of pixels 10 arranged two-dimensionally. The pixel 10 outputs a photoelectric conversion signal and a dark signal, which will be described later, to the second substrate 112. Figure 2In the figure, the pixel 10 at the upper left corner is set as the pixel 10(1, 1) in the first row and the first column, and the pixel 10 at the lower right corner is set as the pixel 10(4, 4) in the fourth row and the fourth column, and 16 pixels 10 in a 4-pixel row direction × 4-pixel column direction are illustrated. In addition, the number of pixels arranged in the imaging element and the arrangement are not limited to the illustrated example.
[0027] The second substrate 112 has a plurality of AD conversion units 40. In the present embodiment, an AD conversion unit 40 is provided for each pixel 10. In Figure 2 the figure, 16 AD conversion units 40 from AD conversion unit 40(1, 1) to AD conversion unit 40(4, 4) are illustrated. The AD conversion unit 40 is composed of a comparison unit and a storage unit, and converts the input photoelectric conversion signal and dark signal into digital signals of a specified number of bits, which will be described later.
[0028] Figure 3 It is a circuit diagram showing a configuration example of a part of the imaging element of the first embodiment. The imaging element 3 has a plurality of pixels 10, a plurality of AD conversion units 40, a read control unit 60, a signal processing unit 70, and an input / output unit 80.
[0029] The pixel 10 has a photoelectric conversion unit 11, a transfer unit 12, a reset unit 13, a floating diffusion (FD) 14, an amplification unit 15, and a current source 16. The photoelectric conversion unit 11 is a photodiode PD, which converts incident light into charge and accumulates the charge obtained after photoelectric conversion. The transfer unit 12 is composed of a transistor M1 controlled by a signal TX, and transfers the charge obtained by photoelectric conversion using the photoelectric conversion unit 11 to the FD 14. The transistor M1 is a transfer transistor. The FD 14 accumulates (holds) the transferred charge. The current source 16 generates a current for reading a signal from the pixel 10, and supplies the generated current to the signal line 18 and the amplification unit 15.
[0030] The amplification unit 15 is composed of a transistor M3 whose gate (terminal) is connected to the FD 14, amplifies the signal based on the charge accumulated in the FD 14, and outputs it to the signal line 18. The transistor M3 is an amplification transistor. The reset unit 13 is composed of a transistor M2 controlled by a signal RST, discharges the charge accumulated in the FD 14, and resets the voltage of the FD 14. The transistor M2 is a reset transistor.
[0031] Pixel 10 sequentially outputs a signal (dark signal) when resetting the voltage of FD14 and a signal (photoelectric conversion signal) corresponding to the charge transferred from the photoelectric conversion unit 11 to FD14 via the transfer unit 12 to the signal line 18. The dark signal becomes an analog signal representing the reference level with respect to the photoelectric conversion signal. In addition, the photoelectric conversion signal is an analog signal generated based on the charge obtained by photoelectric conversion using the photoelectric conversion unit 11. The dark signal and the photoelectric conversion signal sequentially output from pixel 10 are input to the AD conversion unit 40 via the signal line 18 and bumps or the like.
[0032] The AD conversion unit 40 includes a comparison unit 20, a switch SW1, a storage unit 25, and a selection unit 30. The comparison unit 20 is constituted by a comparator circuit. A ramp signal, which is a reference signal that changes over time, is input to the first terminal 21 of the comparison unit 20 from a signal generation circuit (not shown). A signal (photoelectric conversion signal, dark signal) output from pixel 10 to the signal line 18 is directly input to the second terminal 22 of the comparison unit 20 or input after being amplified by an amplification circuit (not shown). The comparison unit 20 compares the signal input from pixel 10 with the reference signal and outputs an output signal as a comparison result from the output terminal 23.
[0033] The comparison unit 20 is connected to the storage unit 25 via the switch SW1. The switch SW1 is constituted by a transistor and electrically connects or disconnects the comparison unit 20 and the storage unit 25. When the switch SW1 is in the conducting state, the output signal of the comparison unit 20 is output to the storage unit 25.
[0034] The storage unit 25 is constituted by a plurality of latch circuits corresponding to the number of bits of the digital signal stored. An output signal representing the comparison result based on the comparison unit 20 is input to one input terminal (G terminal) of each latch circuit via the switch SW1. A clock signal representing a count value is input to the other input terminal (D terminal) of each latch circuit from a counter circuit (not shown). In the Figure 3 example shown, count values cnt<0> to cnt<n> representing the count value are respectively input to the other input terminals (D terminals) of each latch circuit, and the AD conversion unit 40 becomes an n-bit AD conversion circuit.
[0035] The storage unit 25 stores the count value corresponding to the elapsed time from the start of comparison based on the comparison unit 20 to the inversion of the comparison result as a digital signal based on the output signal of the comparison unit 20 and the clock signal from the counter circuit. In other words, the storage unit 25 stores the count value corresponding to the time until the magnitude relationship (inversion) between the level of the signal output from pixel 10 and the level of the reference signal changes as a digital signal based on the signal output from the comparison unit 20.
[0036] If the dark signal of pixel 10 is input to the comparison unit 20, the comparison unit 20 compares the dark signal with the reference signal and outputs the comparison result to the storage unit 25. Based on the comparison result of the comparison unit 20 and the clock signal, the storage unit 25 stores the count value corresponding to the elapsed time from the start of the comparison by the comparison unit 20 until the comparison result is inverted as a digital signal based on the dark signal. Additionally, if the photoelectric conversion signal of pixel 10 is input to the comparison unit 20, the comparison unit 20 compares the photoelectric conversion signal with the reference signal and outputs the comparison result to the storage unit 25. Based on the comparison result of the comparison unit 20 and the clock signal, the storage unit 25 stores the count value corresponding to the elapsed time from the start of the comparison by the comparison unit 20 until the comparison result is inverted as a digital signal based on the photoelectric conversion signal. In this way, the AD conversion unit 40 converts the photoelectric conversion signal, which is an analog signal, into a digital signal of a specified number of bits, and converts the dark signal, which is an analog signal, into a digital signal of a specified number of bits.
[0037] The selection unit 30 is composed of a multiplexer controlled by the signal SEL, and inputs the signal of the pixel converted into a digital signal from the storage unit 25 (in Figure 3 it is an n-bit digital signal). The selection unit 30 outputs the signal of the pixel input from the storage unit 25 to the signal line 50 (hereinafter referred to as the data line). The data line 50 is composed of a plurality of signal lines corresponding to the number of bits of the digital signal output from the AD conversion unit 40. In the imaging element 3, for each column of the plurality of AD conversion units 40 arranged longitudinally, i.e., in the column direction (vertical direction), a data line 50 is provided (in Figure 3 it is n signal lines).
[0038] The signal processing unit 70 is composed of an amplifier circuit, a decoding circuit, etc. Via the data line 50, the signal of the pixel converted into a digital signal (the digital signal based on the dark signal, the digital signal based on the photoelectric conversion signal) is input to the signal processing unit 70. The processing unit 70 performs signal processing such as correlated double sampling and transcoding on the signal input from the AD conversion unit 40 via the data line 50, and outputs it to the input / output unit 80. The input / output unit 80 has an input / output circuit corresponding to a high-speed interface such as SLVS or LVDS. The input / output unit 80 outputs (transmits) the signal input from the signal processing unit 70 to the control unit 4 of the camera 1 at high speed.
[0039] The read control unit 60 is commonly provided for the plurality of pixels 10 and the plurality of AD conversion units 40. The read control unit 60 is composed of a plurality of circuits including a timing generator, and is divided into a first substrate 111 and a second substrate 112 for configuration. In addition, the read control unit 60 can be configured on one of the first substrate 111 and the second substrate 112, and the first substrate 112 and the second substrate 112 can be configured on different substrates.
[0040] The read control unit 60 is controlled by the control unit 4 of the camera 1, and supplies signals such as the signal TX and the signal RST to each pixel 10 to control the operation of each pixel 10. The read control unit 60 supplies signals to the gates of the transistors of each pixel 10, and sets the transistors to an on state (connected state, conducting state, short-circuit state) or an off state (disconnected state, non-conducting state, open state, blocking state).
[0041] The read control unit 60 supplies the signal SEL to the selection unit 30 of each AD conversion unit 40 to control the selection unit 30 of each AD conversion unit 40. If the selection unit 30 is set to an enabled state (conducting state) by the read control unit 60, the signal of the pixel converted into a digital signal input from the storage unit 25 is output to the signal processing unit 70 via the data line 50. The read control unit 60 sequentially sets the selection unit 30 of each AD conversion unit 40 to a conducting state, and outputs the signal of the pixel stored in the storage unit 25 connected to the selection unit 30 set to the conducting state to the data line 50. It can also be said that the read control unit 60 sequentially selects a plurality of AD conversion units 40, and reads out the signal of the pixel converted into a digital signal from the selected AD conversion unit 40. For each data line 50, the signal of the n-bit pixel converted into a digital signal is input to the signal processing unit 70.
[0042] Figure 4 FIG. is a diagram for explaining the read process of the imaging element according to the first embodiment. In the imaging element 3, there is a switch SW2 (in Figure 4 it is switch SW2a to switch SW2h) that connects or disconnects the comparison unit 20 of the AD conversion unit 40 and the storage unit 25 of the AD conversion unit 40 different from this AD conversion unit 40. In the present embodiment, the switch SW2 connects the output terminal 23 of the comparison unit 20 of one AD conversion unit 40 and the input terminal (G terminal) of the storage unit 25 of the other AD conversion unit 40 among two adjacent AD conversion units 40 in the row direction.
[0043] In Figure 4 In the example shown, a switch SW2 is provided between the comparison units 20 of the AD conversion units 40 in the odd-numbered columns and the storage units 25 of the AD conversion units 40 in the even-numbered columns. The switch SW2 is composed of a transistor. For example, the switch SW2a is the connection part 2A, and connects the comparison unit 20 of the AD conversion unit 40(1, 1) and the storage unit 25 of the AD conversion unit 40(1, 2) in the AD conversion unit 40 of the first row. The switch SW2e is the connection part 2e, and connects the comparison unit 20 of the AD conversion unit 40(3, 1) and the storage unit 25 of the AD conversion unit 40(3, 2) in the AD conversion unit 40 of the third row. The read control unit 60 (refer to Figure 3) Signals are supplied to each of the switches SW2a to SW2h, and the on / off control of each switch is performed.
[0044] The read control unit 60 performs processing for individually reading the signals of each pixel of the imaging element 3 (individual read processing), and processing for adding the signals of multiple pixels and reading them out (additive read processing). In the individual read processing, the read control unit 60 selects the AD conversion units 40 of the imaging element 3 from the first row to the fourth row in order by row, and reads out the pixel signals from the selected AD conversion units 40. Figure 4 from the first row to the fourth row in order by row, and reads out the pixel signals from the selected AD conversion units 40.
[0045] In the additive read processing, the read control unit 60 controls the multiple switches SW as shown in Figure 5 (a) of, and connects the respective FD14s of the multiple pixels 10 to each other, thereby adding the signals of the multiple pixels. In addition, the read control unit 60 may control the multiple switches SW as shown in Figure 5 (b) of, and connect the amplification units 15 of the multiple pixels 10 to the same signal line 18, thereby adding the signals of the multiple pixels. The read control unit 60 performs the following processing, that is, it selects, by one row or multiple rows, a part of the AD conversion units 40 (hereinafter referred to as the first AD conversion units) among the multiple AD conversion units 40 of the imaging element 3 into which the signal generated by adding the signals of the multiple pixels is input, and reads out the pixel signals.
[0046] In the present embodiment, the additive read processing has a first read mode, a second read mode, and a third read mode. The first read mode is a mode in which the first AD conversion unit 40 is sequentially selected for each row, and the pixel signals converted into digital signals are read out. The first AD conversion unit 40 is an AD conversion unit 40 selected by excluding specific rows or columns among all the AD conversion units 40. The first AD conversion unit 40 is input with the pixel signals obtained by addition, and converts the pixel signals obtained by addition into digital signals.
[0047] The second read mode is a mode in which the first AD conversion unit 40 is sequentially selected for each multiple rows, and the pixel signals converted into digital signals are read out.
[0048] The third read mode is a mode in which the AD conversion of the pixel signals (for example, photoelectric conversion signals) and the readout of the pixel signals converted into digital signals (for example, digital signals based on dark signals) are performed simultaneously (in parallel). The control unit 4 of the camera 1 controls the read control unit 60 to switch the read method of the pixel signals.
[0049] (Individual read processing)
[0050] In the individual readout process, the readout control unit 60 sets the switches SW1 of the plurality of AD conversion units 40 of the imaging element 3 to the conductive state respectively, and causes each AD conversion unit 40 to perform AD conversion. The readout control unit 60 sequentially selects these plurality of AD conversion units 40 row by row, and sequentially outputs the signals of the pixels converted into digital signals from the selected AD conversion unit 40 to the data line 50.
[0051] (First readout method of addition readout process)
[0052] In the first readout method, the readout control unit 60 sets the switches SW1 of the plurality of first AD conversion units 40 to the conductive state respectively, and performs AD conversion in each of the plurality of first AD conversion units 40. The readout control unit 60 sequentially selects these plurality of first AD conversion units 40 row by row, and outputs the signals of the pixels converted into digital signals from the selected first AD conversion unit 40 to the data line 50. In this way, in the case of the first readout method, the readout control unit 60 uses only the first AD conversion units 40 among all the AD conversion units 40. The other AD conversion units 40 different from the first AD conversion units 40 (hereinafter referred to as second AD conversion units) and the data lines 50 connected to these second AD conversion units 40 are not used in the case of the first readout method and become inoperative states.
[0053] (Second readout method of addition readout process)
[0054] In the second readout method, the readout control unit 60 controls the switch SW1 and the switch SW2. Thus, in addition to the first AD conversion units 40, the storage units 25 and the selection units 30 of the second AD conversion units 40 and the data lines 50 connected to the second AD conversion units 40 are also used. In the second readout method, by using the data lines 50 provided in different columns from each other, it is possible to simultaneously read out the signals of the pixels converted into digital signals from the plurality of rows of AD conversion units 40. When the imaging element 3 selects the first AD conversion units 40 row by row and sequentially reads out the signals of the pixels to the data line 50, it is also possible to read out the signals of the pixels in a short time.
[0055] (Third readout method of addition readout process)
[0056] In the case of the third readout method, the readout control unit 60 uses, in addition to the first AD conversion unit 40, the storage unit 25 and the selection unit 30 of the second AD conversion unit 40, and the data line 50 connected to the second AD conversion unit 40. The readout control unit 60 controls the switch SW1 and the switch SW2, and controls which one of the storage unit 25 of the first AD conversion unit 40 and the storage unit 25 of the second AD conversion unit 40 the output signal of the comparison unit 20 of the first AD conversion unit 40 is output to. It can also be said that the readout control unit 60 switches the storage unit 25 that is the output target based on the comparison result of the comparison unit 20 of the first AD conversion unit 40.
[0057] In the third readout method, when the readout control unit 60 inputs a dark signal to the comparison unit 20 of the first AD conversion unit 40 and when the comparison unit 20 of the first AD conversion unit 40 inputs a photoelectric conversion signal, the readout control unit 60 switches the connection target of the comparison unit 20 of the first AD conversion unit 40 to the storage unit 25 of the first AD conversion unit 40 or the storage unit 25 of the second AD conversion unit 40. For example, when a dark signal is input to the comparison unit 20 of the first AD conversion unit 40, the readout control unit 60 connects the comparison unit 20 of the first AD conversion unit 40 and the storage unit 25 of the first AD conversion unit 40. The comparison unit 20 of the first AD conversion unit 40 outputs an output signal indicating the comparison result between the dark signal and the reference signal to the storage unit 25 of the first AD conversion unit 40 via the switch SW1. The storage unit 25 of the first AD conversion unit 40 stores a digital signal based on the dark signal based on the output signal of the comparison unit 20.
[0058] After the AD conversion of the dark signal is completed, the readout control unit 60 starts reading out the digital signal based on the dark signal from the storage unit 25 of the first AD conversion unit 40 to the data line 50. In addition, the readout control unit 60 connects the comparison unit 20 of the first AD conversion unit 40 and the storage unit 25 of the second AD conversion unit 40. At this time, if a photoelectric conversion signal is input to the comparison unit 20 of the first AD conversion unit 40, the comparison unit 20 of the first AD conversion unit 40 outputs an output signal indicating the comparison result between the photoelectric conversion signal and the reference signal to the storage unit 25 of the second AD conversion unit 40 via the switch SW2. The storage unit 25 of the second AD conversion unit 40 stores a digital signal based on the photoelectric conversion signal based on the output signal of the comparison unit 20 of the first AD conversion unit 40.
[0059] In this way, in the third readout method, when performing AD conversion of the dark signal and when performing AD conversion of the photoelectric conversion signal, different storage units 25 are used for AD conversion. Thereby, it is possible to perform the readout of the digital signal based on the dark signal and the AD conversion of the photoelectric conversion signal in parallel. Similarly, it is possible to perform the readout of the digital signal based on the photoelectric conversion signal and the AD conversion of the dark signal in parallel. Therefore, the imaging element 3 does not need to wait for the end of the readout process of the signal to the data line 50 of the pixel to start the next AD conversion process, and can read the signal of the pixel in a short time. Hereinafter, with reference to Figures 4 - 10 , the first to third readout methods of the individual readout process and the addition readout process will be further described.
[0060] (Individual readout process)
[0061] When the read control unit 60 is instructed by the control unit 4 to perform the individual readout process, as Figure 4 shown, each switch SW1 of the AD conversion units 40(1, 1) to 40(4, 4) is set to the on state, and the switches SW2a to SW2h are set to the off state.
[0062] The read control unit 60 sets the reset units 13 of the pixels 10(1, 1) to 10(4, 4) to the on state respectively. Thereby, in each pixel 10, the voltage of its respective FD14 is reset. The dark signals of the pixels 10(1, 1) to 10(4, 4) output the signal lines 18 connected to the respective pixels 10 to the AD conversion units 40(1, 1) to 40(4, 4) respectively. The AD conversion units 40(1, 1) to 40(4, 4) convert the input dark signals into digital signals. Digital signals based on the dark signals of the pixels 10(1, 1) to 10(4, 4) are stored in the respective storage units 25 of the AD conversion units 40(1, 1) to 40(4, 4).
[0063] The read control unit 60 sets the selection units 30 of the AD conversion units 40(1, 1) to 40(1, 4) that are the AD conversion units of the first row to the on state respectively, and sets the selection units 30 of the AD conversion units 40 of the other rows except the first row to the off state respectively. Thereby, the digital signals based on the respective dark signals of the AD conversion units 40(1, 1) to 40(1, 4) are output to the data lines 50a to 50d via the selection units 30 of the respective AD conversion units 40.
[0064] After reading out the digital signals based on the dark signals of each AD conversion unit 40 in the first row, the read control unit 60 sets the selection units 30 of the AD conversion units 40(2, 1) to AD conversion units 40(2, 4) of the AD conversion unit 40 in the second row to the conducting state, and sets the selection units 30 of the AD conversion units 40 in the other rows except the second row to the off state. Thus, the digital signals based on the respective dark signals of the AD conversion units 40(2, 1) to AD conversion units 40(2, 4) are respectively output to the data lines 50a to 50d via the selection units 30 of the respective AD conversion units 40. Similarly, the read control unit 60 sequentially selects the AD conversion units 40 after the third row one by one in the order of the third row, the fourth row, and the fifth row, and reads out the digital signals based on the dark signals from the selected AD conversion units 40.
[0065] The read control unit 60 sets the transmission units 12 of the pixels 10(1, 1) to pixels 10(4, 4) to the conducting state. Thus, in each pixel 10, the charges obtained by photoelectric conversion using each PD11 are transmitted to the FD14. The respective photoelectric conversion signals of the pixels 10(1, 1) to pixels 10(4, 4) are respectively output to the AD conversion units 40(1, 1) to AD conversion units 40(4, 4) via the signal lines 18 connected to the respective pixels 10. The AD conversion units 40(1, 1) to AD conversion units 40(4, 4) convert the input photoelectric conversion signals into digital signals. Digital signals based on the photoelectric conversion signals of the pixels 10(1, 1) to pixels 10(4, 4) are respectively stored in the respective storage units 25 of the AD conversion units 40(1, 1) to AD conversion units 40(4, 4).
[0066] The read control unit 60 selects row by row in the order of the first row, the second row, the third row, the fourth row, and the fifth row in the same manner as when reading out the digital signals based on the dark signals from each AD conversion unit 40, and reads out the digital signals based on the photoelectric conversion signals from the selected AD conversion units 40.
[0067] In this way, in the individual readout process, the read control unit 60 individually reads out the signals of the pixels of the imaging element 3. The digital signals based on the dark signals and the digital signals based on the photoelectric conversion signals sequentially output to the data lines 50a to 50d are output to the control unit 4 via the input / output unit 80 after signal processing such as correlated double sampling is performed by the signal processing unit 70 (refer to Figure 3 ).
[0068] (First to third readout modes of the addition readout process)
[0069] In the first to third readout methods of the addition readout process, the readout control unit 60 adds the signals of a plurality of pixels for each plurality of pixels. In addition, hereinafter, an example of adding the signals of four pixels will be described for every four pixels of 2 pixels × 2 pixels. The signal obtained by adding the signal of pixel 10(1, 1), the signal of pixel 10(1, 2), the signal of pixel 10(2, 1), and the signal of pixel 10(2, 2) is input to the AD conversion unit 40(1, 1). The signal obtained by adding the signals of pixel 10(1, 3), pixel 10(1, 4), pixel 10(2, 3), and pixel 10(2, 4) is input to the AD conversion unit 40(1, 3). In addition, the signal obtained by adding the signals of pixel 10(3, 1), pixel 10(3, 2), pixel 10(4, 1), and pixel 10(4, 2) is input to the AD conversion unit 40(3, 1), and the signal obtained by adding the signals of pixel 10(3, 3), pixel 10(3, 4), pixel 10(4, 3), and pixel 10(4, 4) is input to the AD conversion unit 40(3, 3).
[0070] The AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) function as the first AD conversion unit described above. In Figure 6 these, the AD conversion units 40 circled in thick lines are examples of the AD conversion units used in the case of the first readout method. In addition, Figure 7 the AD conversion units 40 circled in thick lines in are examples of the AD conversion units used in the case of the second readout method, Figure 8 and Figure 9 the AD conversion units 40 circled in thick lines in are examples of the AD conversion units used in the case of the third readout method.
[0071] (First readout method of addition readout process)
[0072] When the readout control unit 60 is instructed by the control unit 4 to perform the first readout method, as Figure 6As shown, each switch SW1 of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) is set to the conducting state, and the switches SW2a to SW2h are set to the off state. If the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) are input with the added dark signal, they convert the dark signal into a digital signal. Digital signals based on the added dark signal are stored respectively in the respective storage units 25 of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3).
[0073] The read control unit 60 sets the selection units 30 of the AD conversion units 40(1, 1) and 40(1, 3) in the first row to the conducting state respectively, and sets the selection units 30 of the other AD conversion units 40 different from the AD conversion units 40(1, 1) and 40(1, 3) to the off state respectively. Thus, the digital signal based on the added dark signal of the AD conversion unit 40(1, 1) is output to the data line 50a via the selection unit 30 of the AD conversion unit 40(1, 1). In addition, the digital signal based on the added dark signal of the AD conversion unit 40(1, 3) is output to the data line 50c via the selection unit 30 of the AD conversion unit 40(1, 3).
[0074] After reading out the digital signals based on the dark signals from the AD conversion units 40(1, 1) and 40(1, 3) in the first row, the read control unit 60 sets the selection units 30 of the AD conversion units 40(3, 1) and 40(3, 3) in the third row to the conducting state respectively. In addition, the read control unit 60 sets the selection units 30 of the other AD conversion units 40 different from the AD conversion units 40(3, 1) and 40(3, 3) to the off state respectively. Thus, the digital signal based on the added dark signal of the AD conversion unit 40(3, 1) is output to the data line 50a via the selection unit 30 of the AD conversion unit 40(3, 1). In addition, the digital signal based on the added dark signal of the AD conversion unit 40(3, 3) is output to the data line 50c via the selection unit 30 of the AD conversion unit 40(3, 3). Thereafter, similarly, the read control unit 60 sequentially selects the AD conversion units 40 every other row, and reads out the digital signals based on the dark signals from the selected respective AD conversion units 40.
[0075] If the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) are input with the added photoelectric conversion signals, they convert the photoelectric conversion signals into digital signals. Digital signals based on the added photoelectric conversion signals are respectively stored in the respective storage units 25 of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3). Similar to the case of reading out the digital signals based on the dark signals from each AD conversion unit 40, the readout control unit 60 sequentially selects the AD conversion units 40 every other row and reads out the digital signals based on the photoelectric conversion signals from the selected AD conversion units 40.
[0076] In this way, in the first readout method, the readout control unit 60 sequentially selects a part of all the AD conversion units 40 of the imaging element 3 row by row and reads out the signals of the pixels converted into digital signals. The digital signals based on the dark signals and the digital signals based on the photoelectric conversion signals that are sequentially output to the data lines 50a and 50c are output to the control unit 4 through the input / output unit 80 after being subjected to signal processing by the signal processing unit 70.
[0077] (Second readout method of addition readout processing)
[0078] When the readout control unit 60 is instructed by the control unit 4 to perform the second readout method, as Figure 7 shown, the switches SW1 of the AD conversion units 40(1, 1) and 40(1, 3) are set to the conducting state. In addition, the readout control unit 60 sets the switches SW2e and SW2f to the conducting state. By making the switch SW2e conductive, the comparison unit 20 of the AD conversion unit 40(3, 1) and the storage unit 25 of the AD conversion unit 40(3, 2) are electrically connected. In addition, by making the switch SW2f conductive, the comparison unit 20 of the AD conversion unit 40(3, 3) and the storage unit 25 of the AD conversion unit 40(3, 4) are electrically connected. The AD conversion units 40(3, 2) and 40(3, 4) function as the second AD conversion units.
[0079] If the AD conversion units 40(1, 1) and 40(1, 3) are input with the added dark signals, they convert the dark signals into digital signals. Digital signals based on the added dark signals are respectively stored in the respective storage units 25 of the AD conversion units 40(1, 1) and 40(1, 3).
[0080] If the comparison unit 20 of the AD conversion unit 40(3, 1) is input with the added dark signal, it outputs an output signal representing the comparison result between the dark signal and the reference signal to the storage unit 25 of the AD conversion unit 40(3, 2) via the switch SW2e. The storage unit 25 of the AD conversion unit 40(3, 2) stores a digital signal based on the added dark signal based on the output signal of the comparison unit 20 of the AD conversion unit 40(3, 1). In this way, the added dark signal input to the comparison unit 20 of the AD conversion unit 40(3, 1) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 1) and the storage unit 25 of the AD conversion unit 40(3, 2).
[0081] If the comparison unit 20 of the AD conversion unit 40(3, 3) is input with the added dark signal, it outputs an output signal representing the comparison result between the dark signal and the reference signal to the storage unit 25 of the AD conversion unit 40(3, 4) via the switch SW2f. The storage unit 25 of the AD conversion unit 40(3, 4) stores a digital signal based on the added dark signal based on the output signal of the comparison unit 20 of the AD conversion unit 40(3, 3). In this way, the added dark signal input to the comparison unit 20 of the AD conversion unit 40(3, 3) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 3) and the storage unit 25 of the AD conversion unit 40(3, 4).
[0082] The read control unit 60 sets the respective selection units 30 of the AD conversion units 40(1, 1) and 40(1, 3) in the first row, and the respective selection units 30 of the AD conversion units 40(3, 2) and 40(3, 4) in the third row to the conductive state. In addition, the read control unit 60 sets the selection units 30 of the other AD conversion units 40 different from the AD conversion units 40(1, 1), 40(1, 3), 40(3, 2), and 40(3, 4) to the off state.
[0083] The added dark signal input to the comparison unit 20 of the AD conversion unit 40(1, 1) is, as schematically shown by the arrow 90a, output to the data line 50a via the selection unit 30 of the AD conversion unit 40(1, 1) after being converted into a digital signal by the AD conversion unit 40(1, 1). In addition, the added dark signal input to the comparison unit 20 of the AD conversion unit 40(3, 1) is, as schematically shown by the arrow 90b, output to the data line 50b via the selection unit 30 of the AD conversion unit 40(3, 2) after being converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 1) and the storage unit 25 of the AD conversion unit 40(3, 2).
[0084] The added dark signal input to the comparison unit 20 of the AD conversion unit 40(1, 3) is, as schematically shown by the arrow 90c, after being converted into a digital signal by the AD conversion unit 40(1, 3), output to the data line 50c via the selection unit 30 of the AD conversion unit 40(1, 3). Further, the added dark signal input to the comparison unit 20 of the AD conversion unit 40(3, 3) is, as schematically shown by the arrow 90d, after being converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 3) and the storage unit 25 of the AD conversion unit 40(3, 4), output to the data line 50d via the selection unit 30 of the AD conversion unit 40(3, 4). Thereafter, similarly, the read control unit 60 sequentially selects the AD conversion units 40 two rows at a time, and reads out the digital signals based on the dark signals from the selected AD conversion units 40.
[0085] If the AD conversion unit 40(1, 1) and the AD conversion unit 40(1, 3) are input with the added photoelectric conversion signal, they convert the photoelectric conversion signal into a digital signal. Digital signals based on the added photoelectric conversion signal are respectively stored in the storage units 25 of the AD conversion unit 40(1, 1) and the AD conversion unit 40(1, 3). The added photoelectric conversion signal input to the comparison unit 20 of the AD conversion unit 40(3, 1) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 1) and the storage unit 25 of the AD conversion unit 40(3, 2), and stored in the storage unit 25 of the AD conversion unit 40(3, 2). Further, the added photoelectric conversion signal input to the comparison unit 20 of the AD conversion unit 40(3, 3) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(3, 3) and the storage unit 25 of the AD conversion unit 40(3, 4), and stored in the storage unit 25 of the AD conversion unit 40(3, 4).
[0086] The read control unit 60 sequentially selects the AD conversion units 40 two rows at a time, and reads out the digital signals based on the photoelectric conversion signals from the selected AD conversion units 40 in the same way as when reading out the digital signals based on the dark signals from the respective AD conversion units 40.
[0087] In this way, in the second readout method, the readout control unit 60 also uses the AD conversion unit 40 and the data lines 50b and 50d connected to the AD conversion unit 40, which are in a standby state in the case of the first readout method, by controlling the switch SW1 and the switch SW2. Therefore, the readout control unit 60 can sequentially select the AD conversion unit 40 two rows at a time and read out the signals of the pixels converted into digital signals. As a result, compared with the case of sequentially selecting the AD conversion unit 40 row by row and reading out the pixel signals, the pixel signals can be read out in a shorter time. The digital signals based on the dark signals and the digital signals based on the photoelectric conversion signals, which are sequentially output to the data lines 50a to 50d, are output to the control unit 4 by the input / output unit 80 after signal processing is performed by the signal processing unit 70.
[0088] (Third readout method of addition readout processing)
[0089] Figure 8 and Figure 9 FIG. is a diagram for explaining the readout process of the imaging element when the third readout method is instructed by the control unit 4. In Figure 8 , the connection states of the switch SW1 and the switch SW2 in the case where the dark signal added by the comparison unit 20 of the AD conversion unit 40 is input are shown. In Figure 9 , the connection states of the switch SW1 and the switch SW2 in the case where the photoelectric conversion signal added by the comparison unit 20 of the AD conversion unit 40 is input are shown. In addition, in Figure 8 and Figure 9 In the example shown, the AD conversion units 40(1, 2), 40(1, 4), 40(3, 2), and 40(3, 4) function as the second AD conversion unit.
[0090] When the dark signal added by the comparison unit 20 of the AD conversion unit 40 is input, the readout control unit 60, as Figure 8 shown, sets the switches SW1 of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) to the on state. In addition, the readout control unit 60 sets the switches SW2a to SW2h to the off state.
[0091] The read control unit 60 causes each of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) to perform AD conversion of the added dark signal. For example, as schematically shown by an arrow 91a, the added dark signal input to the comparator 20 of the AD conversion unit 40(1, 1) is converted into a digital signal by the AD conversion unit 40(1, 1) and stored in the storage unit 25 of the AD conversion unit 40(1, 1). In addition, as schematically shown by an arrow 91c, the added dark signal input to the comparator 20 of the AD conversion unit 40(1, 3) is converted into a digital signal by the AD conversion unit 40(1, 3) and stored in the storage unit 25 of the AD conversion unit 40(1, 3).
[0092] Simultaneously with the AD conversion of the dark signal, the read control unit 60 reads out the digital signals based on the photoelectric conversion signals stored during the previous AD conversion of the photoelectric conversion signals from the respective storage units 25 of the AD conversion units 40(1, 2), 40(1, 4), 40(3, 2), and 40(3, 4). For example, as schematically shown by an arrow 92b, the digital signal based on the added photoelectric conversion signal is output from the storage unit 25 of the AD conversion unit 40(1, 2) to the data line 50b. In addition, as schematically shown by an arrow 92d, the added digital signal based on the photoelectric conversion signal is output from the storage unit 25 of the AD conversion unit 40(1, 4) to the data line 50d. Thereafter, similarly, the read control unit 60 sequentially selects the AD conversion units 40 every other row and reads out the digital signals based on the photoelectric conversion signals from the selected AD conversion units 40.
[0093] When the added photoelectric conversion signal is input to the comparator 20 of the AD conversion unit 40, the read control unit 60 Figure 9 as shown, sets the switches SW1 of the AD conversion units 40(1, 1), 40(1, 3), 40(3, 1), and 40(3, 3) to the closed state. In addition, the read control unit 60 sets the switches SW2a, SW2b, SW2e, and SW2f to the conducting state.
[0094] The read control unit 60 causes each of the comparison unit 20 of the AD conversion unit 40(1, 1), the storage unit 25 of the AD conversion unit 40(1, 2), the comparison unit 20 of the AD conversion unit 40(1, 3), the storage unit 25 of the AD conversion unit 40(1, 4), the comparison unit 20 of the AD conversion unit 40(3, 1), the storage unit 25 of the AD conversion unit 40(3, 2), the comparison unit 20 of the AD conversion unit 40(3, 3), and the storage unit 25 of the AD conversion unit 40(3, 4) to perform AD conversion on the photoelectric conversion signal after addition. For example, as schematically shown by the arrow 91b, the photoelectric conversion signal after addition input to the comparison unit 20 of the AD conversion unit 40(1, 1) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(1, 1) and the storage unit 25 of the AD conversion unit 40(1, 2), and is stored in the storage unit 25 of the AD conversion unit 40(1, 2). In addition, as schematically shown by the arrow 91d, the photoelectric conversion signal after addition input to the comparison unit 20 of the AD conversion unit 40(1, 3) is converted into a digital signal by the comparison unit 20 of the AD conversion unit 40(1, 3) and the storage unit 25 of the AD conversion unit 40(1, 4), and is stored in the storage unit 25 of the AD conversion unit 40(1, 4).
[0095] Simultaneously with the AD conversion of the photoelectric conversion signal, the read control unit 60 reads out the digital signal based on the dark signal stored during the previous AD conversion of the dark signal from each storage unit 25 of the AD conversion unit 40(1, 1), the AD conversion unit 40(1, 3), the AD conversion unit 40(3, 1), and the AD conversion unit 40(3, 3). For example, as schematically shown by the arrow 92a, the digital signal based on the photoelectric conversion signal after addition is output from the storage unit 25 of the AD conversion unit 40(1, 1) to the data line 50a. In addition, as schematically shown by the arrow 92c, the digital signal based on the photoelectric conversion signal after addition is output from the storage unit 25 of the AD conversion unit 40(1, 3) to the data line 50c. Thereafter, similarly, the read control unit 60 sequentially selects the AD conversion unit 40 every other row, and reads out the digital signal based on the photoelectric conversion signal from each selected AD conversion unit 40.
[0096] In this way, in the third read mode, the read control unit 60 controls the switch SW1 and the switch SW2, whereby different storage units 25 are used for AD conversion in the case of performing AD conversion of the dark signal and in the case of performing AD conversion of the photoelectric conversion signal. As a result, the imaging element 3 can perform AD conversion of the signals of the pixels in parallel and read out the signals of the pixels converted into digital signals to the data line 50. Therefore, the signals of the pixels can be read out in a short time.
[0097] (Comparison of the First to Third Read Modes of the Addition Read Process)
[0098] Figure 10 It is a diagram comparing the first to third readout methods of the addition readout process of the imaging element in the first embodiment. Figure 10 (a) of shows the process in the case of the first readout method, Figure 10 (b) of shows the process in the case of the second readout method, Figure 10 (c) of shows the process in the case of the third readout method. In addition, in Figure 10 (a) to Figure 10 (c), on the same time axis, the readout process of the dark signal from pixel 10, the AD conversion process of the dark signal, the readout process of the digital signal based on the dark signal, the readout process of the photoelectric conversion signal from pixel 10, the AD conversion process of the photoelectric conversion signal, and the readout process of the digital signal based on the photoelectric conversion signal are shown side by side.
[0099] In Figure 10 in the case of the second readout method of (b), as described above, the read control unit 60 sequentially selects the AD conversion units 40 two rows at a time, and reads the digital signal based on the dark signal and the digital signal based on the photoelectric conversion signal. Therefore, compared with the case of the first readout method of Figure 10 (a), the read control unit 60 can read the digital signal based on the dark signal from each AD conversion unit 40 in about 1 / 2 the time, and can also read the digital signal based on the photoelectric conversion signal from each AD conversion unit 40 in about 1 / 2 the time. Thereby, the imaging element 3 can increase the frame rate during photography.
[0100] In Figure 10 in the case of the third readout method of (c), as described above, the read control unit 60 performs the AD conversion of the dark signal (or photoelectric conversion signal) read from the pixel and the readout of the photoelectric conversion signal (or dark signal) converted into a digital signal in parallel. Therefore, compared with the case of the second readout method of Figure 10 (b), the imaging element 3 can further increase the frame rate during photography.
[0101] In addition, it is also possible to consider providing a storage unit for AD conversion and a storage unit for signal readout to the data line 50 for each pixel 10 respectively, but in this case, the area of the imaging element will increase. In the present embodiment, it is not necessary to provide a storage unit for AD conversion and a storage unit for signal readout to the data line 50 separately, and an increase in the area of the imaging element can be prevented.
[0102] According to the above embodiment, the following operational effects can be obtained.
[0103] (1) The imaging element 3 includes: a first photoelectric conversion unit 11 and a second photoelectric conversion unit 11 that generate charges by photoelectric conversion; a first comparison unit 20 that outputs a first signal based on a first comparison result, where the first comparison result is the result of comparing a signal based on the charges generated by the first photoelectric conversion unit 11 with a reference signal; a first storage unit 25 that receives the first signal output from the first comparison unit 20 and stores a signal based on the first signal; a second comparison unit 20 that outputs a second signal based on a second comparison result, where the second comparison result is the result of comparing a signal based on the charges generated by the second photoelectric conversion unit 11 and the reference signal; a second storage unit 25 that receives the second signal output from the second comparison unit 20 and stores a signal based on the second signal; a first connection unit (switch SW2) capable of connecting or disconnecting the first comparison unit 20 and the second storage unit 25; and a control unit (readout control unit) that controls the first connection unit and controls whether to output the first signal to the first storage unit or to the second storage unit. With such a configuration, the readout control unit 60 of the present embodiment controls the switch SW2 to perform the readout process of the pixel signals, thereby shortening the readout time of the pixel signals.
[0104] (2) In the present embodiment, the imaging element controls the switch SW1 and the switch SW2, thereby performing the second readout method and the third readout method. As a result, the readout process of the pixel signals can be performed at high speed. In addition, the frame rate during imaging can be increased.
[0105] The following modifications are also within the scope of the present invention, and one or more of the modification examples can also be combined with the above-described embodiment.
[0106] (Modification Example 1)
[0107] In the above-described embodiment, an example is described in which the readout control unit 60 adds the signals of a plurality of pixels to perform the addition readout process. The readout control unit 60 may also perform a process of reading out signals while excluding pixels in a specific row or column among all pixels (skipping readout process). In the case of the skipping readout process, the readout control unit 60 may also perform the same readout method as the first to third readout methods described above.
[0108] (Modification Example 2)
[0109] In the above-described embodiment, an example is described in which the imaging element 3 is configured by laminating the first substrate 111 and the second substrate 112. However, the first substrate 111 and the second substrate 112 may not be laminated.
[0110] (Modification Example 3)
[0111] In the above-described embodiment, an example is described in which the data line 50 is constituted by a plurality of signal lines corresponding to the number of bits of the digital signal output from the AD conversion unit 40. The data line 50 may be a single signal line or any number of signal lines.
[0112] (Modification Example 4)
[0113] In the above-described embodiment and modification example, an example is described 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.
[0114] (Modification Example 5)
[0115] The imaging element and imaging device described in the above-described embodiment and modification example can be applied to cameras, cameras built into smartphones, tablet computers, PCs, in-vehicle cameras, cameras mounted on unmanned aerial vehicles (UAVs, radio-controlled aircraft, etc.).
[0116] Although various embodiments and modification examples have been described above, the present invention is not limited to these. Other aspects that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention.
[0117] The disclosure of the following priority basis application is incorporated herein by reference.
[0118] Japanese Patent Application No. 2019-69145 (filed on March 29, 2019)
[0119] Description of Reference Numerals
[0120] 1 Imaging device, 3 Imaging element, 4 Control unit, 10 Pixel, 11 Photoelectric conversion unit, 20 Comparison unit, 25 Storage unit, 40 AD conversion unit, 60 Readout control unit.
Claims
1. An imaging element, characterized in that, it comprises: a first pixel having a first photoelectric conversion section that converts light into charge; a second pixel having a second photoelectric conversion section that is a photoelectric conversion section for converting light into charge and is arranged side by side with the first photoelectric conversion section in the row direction; a first signal line electrically connected to the first pixel; a second signal line electrically connected to the second pixel; a first comparison section having a first input terminal electrically connected to the first signal line and a first output terminal; a first storage section electrically connected to the first output terminal; a second comparison section having a second input terminal electrically connected to the second signal line and a second output terminal; and a second storage section electrically connected to the first output terminal and the second output terminal.
2. The imaging element according to claim 1, characterized in that, it comprises: a first data line electrically connected to the first storage section; and a second data line electrically connected to the second storage section.
3. The imaging element according to claim 2, characterized in that, it comprises a signal processing section electrically connected to the first data line and the second data line.
4. The imaging element according to claim 3, characterized in that, the signal processing section performs correlated double sampling processing using the signal output to the first data line and the signal output to the second data line.
5. The imaging element according to claim 2, characterized in that, it comprises: a first selection section for electrically connecting the first storage section and the first data line; and a second selection section for electrically connecting the second storage section and the second data line.
6. The imaging element according to claim 5, characterized in that, the first storage section has a first latch circuit and a second latch circuit, the second storage section has a third latch circuit and a fourth latch circuit, the first selection section controls the electrical connection between the first latch circuit and the first data line and the electrical connection between the second latch circuit and the first data line, the second selection section controls the electrical connection between the third latch circuit and the second data line and the electrical connection between the fourth latch circuit and the second data line.
7. The imaging element according to claim 1, characterized in that, the first pixel has a first floating diffusion section, and the charge converted by the first photoelectric conversion section is transferred to the first floating diffusion section, the second pixel has a second floating diffusion section, and the charge converted by the second photoelectric conversion section is transferred to the second floating diffusion section.
8. The imaging element according to claim 7, characterized in that, it comprises a connection section for electrically connecting the first floating diffusion section and the second floating diffusion section.
9. The imaging element according to claim 8, characterized in that, the connection section has a first switch for electrically connecting the first floating diffusion section and the second floating diffusion section.
10. The imaging element according to claim 9, characterized in that, The connection portion has a second switch that electrically connects the first floating diffusion portion and the second floating diffusion portion. The second switch is serially connected to the first switch between the first floating diffusion portion and the second floating diffusion portion.
11. The imaging element according to claim 10, wherein, the connection portion has a third switch that electrically connects the first floating diffusion portion and the second floating diffusion portion, the third switch is serially connected to the first switch and the second switch between the first floating diffusion portion and the second floating diffusion portion.
12. The imaging element according to claim 1, wherein, it includes a connection portion for electrically connecting the first signal line and the second signal line.
13. The imaging element according to claim 12, wherein, the connection portion has a first switch that electrically connects the first signal line and the second signal line.
14. The imaging element according to claim 13, wherein, the connection portion has a second switch that electrically connects the first signal line and the second signal line, the second switch is serially connected to the first switch between the first signal line and the second signal line.
15. The imaging element according to claim 14, wherein, the connection portion has a third switch that electrically connects the first signal line and the second signal line, the third switch is serially connected to the first switch and the second switch between the first signal line and the second signal line.
16. The imaging element according to claim 1, wherein, the first photoelectric conversion portion and the second photoelectric conversion portion are disposed on a first substrate, the first storage portion and the second storage portion are disposed on a second substrate laminated with the first substrate.
17. The imaging element according to claim 16, wherein, the first comparison portion and the second comparison portion are disposed on the second substrate.
18. The imaging element according to claim 1, wherein, the first comparison portion has a third input terminal to which a reference signal is input, and the reference signal is used to compare with the signal value of the signal input to the first input terminal.
19. The imaging element according to claim 18, wherein, a ramp signal whose signal value changes over time is input to the third input terminal as the reference signal.
20. The imaging element according to claim 1, wherein, the second photoelectric conversion portion is disposed adjacent to the first photoelectric conversion portion in the row direction.
21. The imaging element according to claim 1, wherein, the second comparison portion is disposed side by side with the first comparison portion in the row direction.
22. The imaging element according to claim 1, wherein, it includes: a third pixel having a third photoelectric conversion portion that is a photoelectric conversion portion for converting light into charges and is disposed side by side with the first photoelectric conversion portion in the column direction; a third signal line electrically connected to the third pixel; A third comparison unit having a third input terminal electrically connected to the third signal line and a third output terminal; and A third storage unit electrically connected to the third output terminal.
23. The imaging element according to claim 22, characterized in that it comprises: A first data line electrically connected to the first storage unit and the third storage unit; and A second data line electrically connected to the second storage unit.
24. The imaging element according to claim 23, characterized in that it comprises a signal processing unit electrically connected to the first data line and the second data line.
25. The imaging element according to claim 24, characterized in that the signal processing unit performs correlated double sampling processing using the signal output to the first data line and the signal output to the second data line.
26. The imaging element according to claim 23, characterized in that it comprises: A first selection unit for electrically connecting the first storage unit and the first data line; A second selection unit for electrically connecting the second storage unit and the second data line; and A third selection unit for electrically connecting the third storage unit and the first data line.
27. The imaging element according to claim 26, characterized in that the first storage unit has a first latch circuit and a second latch circuit, the second storage unit has a third latch circuit and a fourth latch circuit, the third storage unit has a fifth latch circuit and a sixth latch circuit, the first selection unit controls the electrical connection between the first latch circuit and the first data line and the electrical connection between the second latch circuit and the first data line, the second selection unit controls the electrical connection between the third latch circuit and the second data line and the electrical connection between the fourth latch circuit and the second data line, the third selection unit controls the electrical connection between the fifth latch circuit and the first data line and the electrical connection between the sixth latch circuit and the first data line.
28. The imaging element according to claim 22, characterized in that the first pixel has a first floating diffusion portion, and the charge converted by the first photoelectric conversion portion is transmitted to the first floating diffusion portion, the second pixel has a second floating diffusion portion, and the charge converted by the second photoelectric conversion portion is transmitted to the second floating diffusion portion, the third pixel has a third floating diffusion portion, and the charge converted by the third photoelectric conversion portion is transmitted to the third floating diffusion portion.
29. The imaging element according to claim 28, characterized in that it comprises a connection portion for electrically connecting the first floating diffusion portion, the second floating diffusion portion, and the third floating diffusion portion.
30. The imaging element according to claim 29, characterized in that the connection portion has a first switch for electrically connecting the first floating diffusion portion and the third floating diffusion portion.
31. The imaging element according to claim 30, characterized in that the first switch electrically connects the first floating diffusion portion and the second floating diffusion portion.
32. The imaging element according to claim 30, wherein, the connection portion has a second switch that electrically connects the first floating diffusion portion and the third floating diffusion portion, and the second switch is connected in series with the first switch between the first floating diffusion portion and the third floating diffusion portion.
33. The imaging element according to claim 32, wherein, the second switch electrically connects the second floating diffusion portion and the third floating diffusion portion.
34. The imaging element according to claim 32, wherein, the connection portion has a third switch that electrically connects the first floating diffusion portion and the second floating diffusion portion, and the third switch is connected in series with the first switch between the first floating diffusion portion and the second floating diffusion portion.
35. The imaging element according to claim 34, wherein, the third switch is connected in series with the second switch between the second floating diffusion portion and the third floating diffusion portion.
36. The imaging element according to claim 34, wherein, the connection portion has a fourth switch that electrically connects the first floating diffusion portion and the second floating diffusion portion, and the fourth switch is connected in series with the first switch and the third switch between the first floating diffusion portion and the second floating diffusion portion.
37. The imaging element according to claim 36, wherein, the fourth switch is connected in series with the second switch and the third switch between the second floating diffusion portion and the third floating diffusion portion.
38. The imaging element according to claim 22, wherein, it includes a connection portion for electrically connecting the first signal line, the second signal line, and the third signal line.
39. The imaging element according to claim 29, wherein, the connection portion has a first switch that electrically connects the first signal line and the third signal line.
40. The imaging element according to claim 39, wherein, the first switch electrically connects the first signal line and the second signal line.
41. The imaging element according to claim 39 or 40, wherein, the connection portion has a second switch that electrically connects the first signal line and the third signal line, and the second switch is connected in series with the first switch between the first signal line and the third signal line.
42. The imaging element according to claim 41, wherein, the second switch electrically connects the second signal line and the third signal line.
43. The imaging element according to claim 41, wherein, the connection portion has a third switch that electrically connects the first signal line and the second signal line, and the third switch is connected in series with the first switch between the first signal line and the second signal line.
44. The imaging element according to claim 43, wherein, the third switch is connected in series with the second switch between the second signal line and the third signal line.
45. The imaging element according to claim 43, wherein, The connection part has a fourth switch that electrically connects the first signal line and the second signal line. The fourth switch is connected in series with the first switch and the third switch between the first signal line and the second signal line.
46. The imaging element according to claim 45, wherein, the fourth switch is connected in series with the second switch and the third switch between the second signal line and the third signal line.
47. The imaging element according to claim 22, wherein, the first photoelectric conversion part, the second photoelectric conversion part, and the third photoelectric conversion part are arranged on a first substrate, the first storage part, the second storage part, and the third storage part are arranged on a second substrate laminated with the first substrate.
48. The imaging element according to claim 47, wherein, the first comparison part, the second comparison part, and the third comparison part are arranged on the second substrate.
49. The imaging element according to claim 22, wherein, the first comparison part has a fourth input terminal, and a reference signal is input to the fourth input terminal, and the reference signal is used to compare with the signal value of the signal input to the first input terminal.
50. The imaging element according to claim 49, wherein, a ramp signal whose signal value changes over time is input to the fourth input terminal as the reference signal.
51. The imaging element according to claim 22, wherein, the second photoelectric conversion part is arranged adjacent to the first photoelectric conversion part in the row direction.
52. The imaging element according to claim 51, wherein, the third photoelectric conversion part is arranged adjacent to the first photoelectric conversion part in the column direction.
53. The imaging element according to claim 22, wherein, the third photoelectric conversion part is arranged adjacent to the first photoelectric conversion part in the column direction.
54. The imaging element according to claim 22, wherein, the second comparison part is arranged side by side with the first comparison part in the row direction.
55. The imaging element according to claim 54, wherein, the third comparison part is arranged side by side with the first comparison part in the column direction.
56. The imaging element according to claim 22, wherein, the third comparison part is arranged side by side with the first comparison part in the column direction.
57. The imaging element according to claim 22, wherein, it includes: a fourth pixel having a fourth photoelectric conversion part, the fourth photoelectric conversion part being a photoelectric conversion part that converts light into charges and being arranged side by side with the second photoelectric conversion part in the column direction; a fourth signal line electrically connected to the fourth pixel; a fourth comparison part electrically connected to the fourth signal line; and a fourth storage part electrically connected to the fourth comparison part.
58. The imaging element according to claim 57, wherein, the fourth photoelectric conversion part is arranged adjacent to the second photoelectric conversion part in the column direction.
59. The imaging element according to claim 58, wherein, the fourth photoelectric conversion section is disposed adjacent to the third photoelectric conversion section in the row direction.
60. An imaging device, wherein, it includes the imaging element according to any one of claims 1 to 59.
61. The imaging device according to claim 60, wherein, it includes a generation section that generates image data based on a signal output from the imaging element.
62. The imaging device according to claim 60, wherein, it includes an optical system that forms an image of a subject on the imaging element.
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