Photoelectric conversion device and apparatus

Abstract

To provide a technique advantageous for reducing a circuit scale.SOLUTION: A photoelectric conversion device comprises a plurality of pixels, and a correction unit that corrects a black level of pixel signals output from the plurality of pixels according to data for correction. The correction unit is configured to, when there is a change in the state of a photoelectric conversion system in which the photoelectric conversion device is arranged in a period of one frame to obtain signals for creating one image, change the level of selection signals from a first level to a second level, and select a setting for generating the data for correction from a plurality of settings according to the level.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion device and an apparatus. [Background technology]

[0002] It is known that in a photoelectric conversion device having a plurality of pixels arranged in a matrix, the black level of a signal is corrected using a correction value generated based on a signal output from light-shielded pixels arranged in a light-shielded region. When signals are read out from the light-receiving region for each pixel row, if the power supply voltage fluctuates due to noise or other factors, row-wise noise (horizontal stripe noise) may occur in the image obtained from the readout signals. Patent Document 1 discloses that, in order to suppress horizontal stripe noise, a correction signal is generated by separating an offset signal based on the signals read out from the light-shielded pixels into multiple frequency components, multiplying each frequency component by a coefficient corresponding to the frequency component, and adding the resulting signals together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-284358 Summary of the Invention [Problem to be solved by the invention]

[0004] To perform the processing described in Patent Document 1, the circuit scale of the photoelectric conversion device may become large.

[0005] An object of the present invention is to provide a technique that is advantageous in reducing the circuit scale. [Means for solving the problem]

[0006] In view of the above problems, a photoelectric conversion device according to an embodiment of the present invention is a photoelectric conversion device comprising a plurality of pixels and a correction unit that corrects the black level of pixel signals output from the plurality of pixels in accordance with correction data, wherein the correction unit is configured to change the level of a selection signal from a first level to a second level when the state of a photoelectric conversion system in which the photoelectric conversion device is arranged changes during a period of one frame in which signals for generating one image are obtained, and to select a setting for generating the correction data from a plurality of settings in accordance with the level. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique that is advantageous in suppressing the circuit scale. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a photoelectric conversion device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a photoelectric conversion unit of the photoelectric conversion device of the present embodiment. [Figure 3] FIG. 2 is a diagram showing an example of the configuration of an AD conversion unit of the photoelectric conversion device of the present embodiment. [Figure 4] 4 is a timing chart showing the mechanism by which horizontal stripe noise occurs during AD conversion in the photoelectric conversion device of this embodiment. FIG. [Figure 5] FIG. 2 is a diagram showing an example of the configuration of an OB clamp processing unit of the correction unit of the photoelectric conversion device of this embodiment. [Figure 6] FIG. 2 is a diagram showing an example of the configuration of a correction value generation circuit of an OB clamp processing unit of the present embodiment. [Figure 7] FIG. 2 is a block diagram showing an example of the configuration of a detection unit of the photoelectric conversion device of the present embodiment. [Figure 8] FIG. 4 is a flowchart showing signal processing of the photoelectric conversion device of the present embodiment. [Figure 9] FIG. 2 is a diagram showing an example of the configuration of a detection unit of the photoelectric conversion device of the present embodiment. [Figure 10] FIG. 2 is a diagram showing an example of the configuration of a pixel of the photoelectric conversion device according to the embodiment. [Figure 11]FIG. 2 is a diagram showing an example of the configuration of a photoelectric conversion unit of the photoelectric conversion device of the present embodiment. [Figure 12] FIG. 2 is a diagram showing an example of the configuration of a photoelectric conversion unit of the photoelectric conversion device of the present embodiment. [Figure 13] FIG. 4 is a timing chart showing vertical scanning of the photoelectric conversion device of the present embodiment. [Figure 14] FIG. 2 is a diagram showing an example of the configuration of an OB clamp processing unit of the correction unit of the photoelectric conversion device of this embodiment. [Figure 15] FIG. 2 is a diagram showing an example of the configuration of a smear detection unit of an OB clamp processing unit of the photoelectric conversion device of the present embodiment. [Figure 16] FIG. 4 is a flowchart showing signal processing of the photoelectric conversion device of the present embodiment. [Figure 17] FIG. 1 is a diagram showing an example of the configuration of a photoelectric conversion device according to an embodiment of the present invention. [Figure 18] FIG. 1 is a diagram showing an example of the configuration of a device incorporating a photoelectric conversion device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] A photoelectric conversion device according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 18. FIG. 1 is a diagram illustrating an example configuration of a photoelectric conversion device 100 according to the present disclosure. The photoelectric conversion device 100 includes a photoelectric conversion unit 101 having a plurality of pixels 102 arranged therein and a correction unit 150 that corrects the black level of pixel signals output from the plurality of pixels 102 in accordance with correction data. The correction unit 150 includes a detection unit 107 and a signal processing unit 108. The photoelectric conversion unit 101 includes a light-receiving region and a light-blocking region, which will be described later, and outputs image data to be processed by the signal processing unit 108. The photoelectric conversion device 100 may further include a power supply unit 109 that supplies a power supply voltage to the entire device, a vertical scanning unit 103, a control unit 104, an AD conversion unit 105, and a horizontal scanning unit 106. In this embodiment, the correction unit 150 is arranged within the photoelectric conversion device 100. However, this is not limiting. For example, the signal processing unit 108 may be separate from the photoelectric conversion device 100. Also, for example, the detection unit 107 may be separate from the photoelectric conversion device 100. Furthermore, for example, the correction unit 150 including the detection unit 107 and the signal processing unit 108 may be separate from the photoelectric conversion device 100.

[0011] The photoelectric conversion unit 101 is composed of (m) × (n) pixels, with m pixels 102 arranged in the row direction (horizontal direction in FIG. 1) and n pixels arranged in the column direction (vertical direction in FIG. 1). The vertical scanning unit 103 is connected to the m pixels 102 via row selection lines 110 arranged corresponding to each row, and selects a pixel row from which to read out signals. In the selected pixel row, signals output from the m pixels 102 included in the selected row are simultaneously read out to the AD conversion unit 105 via vertical output lines 111.

[0012] A setting signal, such as an imaging condition when capturing an image using the photoelectric conversion device 100, is input to the control unit 104. The setting signal may be supplied, for example, from a control unit of a photoelectric conversion system in which the photoelectric conversion device 100 is arranged. The control unit 104 supplies control signals corresponding to the setting signal to each component included in the photoelectric conversion device 100. A synchronization signal is also input to the control unit 104, and the control unit 104 controls the operation timing of the vertical scanning unit 103, the AD conversion unit 105, the horizontal scanning unit 106, the detection unit 107, and the signal processing unit 108 based on the setting signal and the synchronization signal.

[0013] The AD conversion unit 105 converts the signals output from the pixels 102 from analog signals to digital signals (AD conversion) by, for example, slope-type AD conversion. The digital signals are read out to a signal processing unit 108 with reference to a signal from a horizontal scanning unit 106.

[0014] The detection unit 107 of the correction unit 150 generates a selection signal based on the setting signal. The selection signal is output to the signal processing unit 108 of the correction unit 150. The signal processing unit 108 performs processing to reduce reset noise generated in switch elements (e.g., MOS transistors) included in each pixel 102 of the photoelectric conversion unit 101. Furthermore, the image data output from the photoelectric conversion unit 101 may contain variations (fixed pattern noise: FPN) generated due to dark currents generated by photodiodes included in the pixels 102 and differences in circuit-related factors such as power supply impedance and signal delay. In this specification, the state in which this FPN changes regularly from row to row and column to column is referred to as shading. After reducing the reset noise component, the signal processing unit 108 averages the light-shielded data for each row and column to generate correction data including FPN components and shading components. The signal processing unit 108 of the correction unit 150 may generate correction data using inter-pixel smoothing processing or inter-row smoothing processing. Next, the signal processing unit 108 performs processing to correct variations between columns and processing to correct dark current components of the pixels.

[0015] FIG. 2 is a conceptual diagram illustrating pixel signals output from a photoelectric conversion unit 101 arranged according to the arrangement of pixels 102 disposed in the photoelectric conversion unit 101 in this embodiment. The photoelectric conversion unit 101 includes a light-receiving region 201 that receives incident light that has passed through an optical system such as a lens, and a light-shielded region 202 that optically shields the incident light. The light-shielded region 202 is a reference region for determining a so-called black level reference for pixel signals obtained by the photoelectric conversion unit 101. The signal processing unit 108 of the correction unit 150 generates correction data from signal values based on light-shielded signals output from pixels 102 disposed in the light-shielded region 202 among the multiple pixels 102. Here, within the light-shielded region 202, the region in which all columns of pixels 102 are optically shielded from light at the top of the screen, as shown in FIG. 2, is referred to as a VOB region 203. An area located, for example, on the left side of the light receiving area 201 and optically shielding the pixels 102 across all rows is called an HOB area 204 .

[0016] FIG. 3 is a block diagram of the AD conversion unit 105 according to this embodiment. The AD conversion unit 105 includes a ramp signal generation circuit 301, a counter 302, a readout circuit 303, a comparison circuit 304, and a memory 305. The ramp signal generation circuit 301 generates a ramp signal and supplies it to the comparison circuit 304. The counter 302 generates a count value and supplies it to the memory 305. The readout circuit 303 may include an amplifier and amplify signals output from the pixels 102 via the vertical output lines 111. The comparison circuit 304 receives the ramp signal and the pixel signal and outputs an inverted signal when the voltage of the ramp signal exceeds the voltage of the pixel signal. The memory 305 receives the count value and the inverted signal and stores the count value at the time the inverted signal is input in a storage element within the memory 305 as a digital signal. The horizontal scanning unit 106 outputs the addressed digital signal to the signal processing unit 108.

[0017] When the AD conversion unit 105 performs processing on analog signals, such as signal amplification and AD conversion, horizontal stripe noise occurs due to power supply fluctuations. This power supply fluctuation may be caused by the operation of a device (hereinafter, sometimes referred to as an external device) other than the photoelectric conversion device constituting the photoelectric conversion system in which the photoelectric conversion device 100 is arranged. For example, suppose that a control unit of the photoelectric conversion system supplies a setting signal to the photoelectric conversion device 100 within a period of one frame in which a signal for generating one image is obtained. At that time, a circuit that holds the setting signal in the photoelectric conversion device 100 is activated, and power supply fluctuations occur due to coupling with the power supply voltage. In the image output from the photoelectric conversion device 100, horizontal stripe noise is superimposed on rows that were amplified and AD converted during the writing period of the setting signal.

[0018] In principle, this horizontal stripe noise has the same noise level in each pixel signal if the timing from when the pixel signals are read out to when they are stored in the memory element is simultaneous. Also, the amount of this horizontal stripe noise is generally smaller than the random noise caused by the pixels 102. However, horizontal stripe noise is more visible than random noise, and even if the amount of noise is small, it has a significant impact on image quality.

[0019] In the present embodiment, as an example of a change in the state of the photoelectric conversion system, such as the operating mode of an external device, during one frame period, an example of a communication operation in which the control unit of the photoelectric conversion system writes a setting signal to the photoelectric conversion device 100 has been described above. However, the state change of the photoelectric conversion system is not limited to this. An example of a change in the state of the photoelectric conversion system is a communication operation in which image data is output from the photoelectric conversion device 100 to a recording unit of the photoelectric conversion system. Another example of a change in the state of the photoelectric conversion system is the operation of driving a motor that adjusts the lens position during autofocus in a lens unit of the photoelectric conversion system. In other words, examples of a change in the state of the photoelectric conversion system include communication between the photoelectric conversion device 100 and a device (external device) other than the photoelectric conversion device itself in the photoelectric conversion system, or driving a motor in the external device.

[0020] FIG. 4 is a timing diagram illustrating the mechanism by which horizontal stripe noise occurs during AD conversion in this embodiment. When the external device is operating in normal mode, fluctuations in the power supply voltage supplied from the power supply unit 109 in the photoelectric conversion device 100 are small, or the AD conversion process and fluctuations in the power supply voltage are synchronous. Therefore, horizontal stripe noise is unlikely to occur in the image data output from the photoelectric conversion device 100. When the operating mode of the external device changes and the state of the photoelectric conversion system changes, the power supply voltage fluctuates, causing jitter in the clock signal CLK in the photoelectric conversion device 100 and degrading the linearity characteristics of the ramp signal generated by the ramp signal generation circuit 301. This causes a shift in the timing at which the inverted signal is output from the comparison circuit 304. As a result, offset noise is superimposed on the digital signal stored in the memory 305.

[0021] Because fluctuations in the power supply voltage within photoelectric conversion device 100, which are caused by changes in the state of the photoelectric conversion system, are asynchronous with the AD conversion, various levels of offset noise are generated for each AD conversion. Since pixel signals output from a given pixel row are AD converted at the same timing, a uniform offset noise is added to that pixel row, and horizontal stripe noise appears in the image data output from photoelectric conversion device 100.

[0022] As shown in FIG. 4, when the state of the photoelectric conversion system in which the photoelectric conversion device 100 is disposed changes, the level of the selection signal is changed from level 0 to level 1. A signal indicating a change in the state of the photoelectric conversion system is supplied as a setting signal, for example, from a control circuit of the photoelectric conversion system to the detection unit 107 of the correction unit 150. The detection unit 107 of the correction unit 150 then detects a change in the state of the photoelectric conversion system, such as the operating mode of an external device, and changes the level of the selection signal it generates. As shown in FIG. 4, the detection unit 107 may maintain the level of the selection signal at level 1 throughout the detection period during which it is detecting a change in the state of the photoelectric conversion system. Furthermore, as shown in FIG. 4, the detection unit 107 may change the level of the selection signal it generates even if it detects a change in the state of the photoelectric conversion system during a one-frame period in which signals for generating one image are obtained. The selection signal is supplied to the signal processing unit 108 of the correction unit 150.

[0023] In this embodiment, an example of the power supply voltage fluctuation is shown in which the power supply voltage fluctuates in a sine wave pattern. However, the shape of the power supply voltage fluctuation is not limited to this. The power supply voltage fluctuation may not have periodicity, for example, it may be completely random noise.

[0024] 5 is a block diagram of an OB clamp processing unit 500 included in the signal processing unit 108 of the correction unit 150. The OB clamp processing unit 500 includes a generation circuit 501 that generates correction data for correcting the black level of pixel signals output from pixels 102 arranged in the photoelectric conversion unit 101, and a correction circuit 502 that corrects the pixel signals in accordance with the correction data. In other words, the OB clamp processing unit 500 corrects the dark current component of the pixel signals using correction data generated from signal values based on light-shielded signals output from pixels 102 arranged in the light-shielded region 202 out of the multiple pixels 102. This processing is referred to as OB clamp processing.

[0025] The generation circuit 501 generates correction data from a signal value based on a light-shielded signal using settings according to a selection signal supplied from the detection unit 107. The correction circuit 502 corrects the pixel signal by subtracting the correction data generated by the generation circuit 501 from the pixel signal acquired by the pixels 102 arranged in the light-receiving area 201. Here, the area for each pixel row or pixel column for acquiring correction data in the photoelectric conversion unit 101 can be set arbitrarily within the light-shielded area 202. The correction data generated from the light-shielded signal is referred to as a clamp value.

[0026] 6 is a block diagram of a generation circuit 501 that generates correction data (clamp values) in this embodiment. The generation circuit 501 includes an average calculation circuit 601, a selection circuit 602, an attenuation circuit 603, and a clamp value holding circuit 604. The generation circuit 501 subtracts a clamp value held in a clamp value holding circuit 604 from the average value of light-shielded signals, for example, calculated by the average calculation circuit 601, for each pixel row. The result of this subtraction is attenuated by the attenuation circuit 603 using settings such as a correction coefficient selected by the selection circuit 602 in accordance with the level of a selection signal, and a new clamp value is generated by filtering the result and added to the clamp value held in the clamp value holding circuit 604. The generated new clamp value is held in the clamp value holding circuit 604. In other words, the generation circuit 501 is configured to select a setting for generating a clamp value (correction data) from multiple settings in accordance with the level of a selection signal supplied from the detection unit 107.

[0027] In this embodiment, the filtering process performed by the generation circuit 501 generates a clamp value by filtering the light-shielded signal for each pixel row through an infinite impulse response low-pass filter (IIR LPF). The filtering process may use such an IIR IPF in order to reduce row variations. However, the filtering process is not limited to the IIR LPF and may be, for example, an integral average, as long as an average value based on the light-shielded signal can be obtained as the clamp value. This allows the generation circuit 501 to generate correction data using inter-pixel smoothing or inter-row smoothing.

[0028] The average value calculation circuit 601 calculates the average value of the light-shielded signals using the light-shielded signals acquired from the pixels 102 arranged in the light-shielded region 202. The selection signal supplied from the detection unit 107 is a signal that conveys to the selection circuit 602 a change in the state of the photoelectric conversion system, such as a change in the operating mode of an external device, as described above. The selection circuit 602 selects either setting 1 or setting 2 based on the level of the selection signal. In the configurations shown in FIGS. 3 and 4, when the level of the selection signal is level 0, setting 1 is selected, and when the level of the selection signal is level 1, setting 2 is selected. The attenuation circuit 603 uses the correction coefficient of the setting selected by the selection circuit 602 to set the attenuation amount of the IIR type LPF connected to the input node of the signal value (average value) based on the light-shielded signal.

[0029] For example, it is assumed that the tracking ability of the IIR LPF is higher when the correction coefficient set in the attenuation circuit 603 as setting 2 is set than when the correction coefficient set in the attenuation circuit 603 as setting 1. In this case, the detection unit 107 may generate a selection signal so that the clamp value is generated using setting 1 under normal circumstances, and when a change in the state of the photoelectric conversion system, such as the operating mode of an external device, is detected, the clamp value is generated using setting 2. When the state of the photoelectric conversion system changes, horizontal stripe noise can be corrected more effectively by selecting the correction coefficient of setting 2, which has higher tracking ability than under normal circumstances.

[0030] In the configurations shown in FIGS. 3 and 4, the detection unit 107 outputs two levels of selection signal, level 0 and level 1, and the generation circuit 501 generates a clamp value using a setting selected from two settings for the selection signal level. However, the types of selection signal and the settings for generating the clamp value are not limited to two. For example, the detection unit 107 may generate a signal with multiple levels as the selection signal level in response to changes in the state of the photoelectric conversion system. Accordingly, the generation circuit 501 may generate a clamp value using a setting selected from three or more settings.

[0031] Furthermore, for example, when the state of the photoelectric conversion system is in a predetermined state, the detection unit 107 may maintain the level of the selection signal at level 0 regardless of changes in the state of the photoelectric conversion system. In other words, when the state of the photoelectric conversion system is in a predetermined state, the selection circuit 602 of the generation circuit 501 may generate a clamp value without switching the setting to setting 1 regardless of changes in the state of the photoelectric conversion system. In this case, a signal indicating that the state of the photoelectric conversion system is in the predetermined state may be directly supplied to the selection circuit 602.

[0032] For example, when a setting such as a correction coefficient is changed, under certain shooting conditions, a type of noise other than horizontal stripe noise may occur. If the generated noise is expected to be more dominant than the horizontal stripe noise, operating the attenuation circuit 603 without changing the setting may reduce degradation in image quality. For example, when shooting at high sensitivity, random noise is large, and switching to Setting 2 with high tracking capability may increase the random noise. When the random noise component is larger than the horizontal stripe noise component, the detection unit 107 prioritizes random noise reduction (preventing random noise increase) over horizontal stripe noise correction, and leaves the level of the selection signal at Level 0. On the other hand, when shooting at low sensitivity, random noise is small, and switching to Setting 2 with high tracking capability only results in a limited increase in random noise. In this case, since the random noise component is expected to be smaller than the horizontal stripe noise component, the detection unit 107 prioritizes horizontal stripe noise correction and switches the level of the selection signal from Level 0 to Level 1 when it detects a change in the state of the photoelectric conversion system as described above. For example, information about the sensitivity during shooting is supplied as the setting signal to the detection unit 107. When the sensitivity of the photoelectric conversion system is set to a predetermined sensitivity or higher, the detection unit 107 may maintain the level of the selection signal at level 0 regardless of changes in the state of the photoelectric conversion system.

[0033] 7 is a block diagram of the detection unit 107 in this embodiment. The detection unit 107 includes a signal detection circuit 701 and a selection signal generation circuit 702. The signal detection circuit 701, for example, refers to a setting signal supplied from a control unit of the photoelectric conversion system, and when it detects a change in the setting signal, determines that the state of the photoelectric conversion system, such as the operating mode of an external device, has changed. In this case, the selection signal generation circuit 702 changes the level of the selection signal from level 0 to level 1 and supplies it to the generation circuit 501. In this embodiment, the detection unit 107 is described as a component of the photoelectric conversion device 100. However, as long as the detection unit 107 can refer to the setting signal and generate a selection signal, it may be arranged outside the photoelectric conversion device 100, as described above.

[0034] 8 is a flowchart showing signal processing in the correction unit 150 (the OB clamp processing unit 500 arranged in the detection unit 107 and the signal processing unit 108). The correction unit 150 corrects horizontal stripe noise using steps S801 to S807 shown in FIG.

[0035] First, in S801, a change in the state of the photoelectric conversion system, such as a change in the mode of the external device, is detected. By referring to the setting signal supplied as described above, a change in the state of the photoelectric conversion system is detected when a communication operation or driving of a motor of the external device is performed.

[0036] Next, in S802, a selection signal is generated. The selection signal generation circuit 702 of the detection unit 107 generates a signal of level 0 as the selection signal when the external device is operating normally, and generates a signal of level 1 as the selection signal when a change in the state of the photoelectric conversion system is detected. For example, the selection signal generation circuit 702 may supply a signal of ground level (no pressure) as the level 0 signal during normal operation, and apply a predetermined voltage to the signal line that supplies the selection signal as a level 1 signal when a change in the state of the photoelectric conversion system is detected. The generated selection signal is supplied to the generation circuit 501 of the OB clamp processing unit 500.

[0037] In S803, the selection circuit 602 of the generation circuit 501 determines the level of the selection signal. If the selection signal is level 0 (Yes), the process proceeds to S804, where a correction coefficient according to setting 1 is set in the attenuation circuit 603. If the selection signal is not level 0 (No), the process proceeds to S805, where a correction coefficient according to setting 2 is set in the attenuation circuit 603.

[0038] Next, in S806, as described above, the clamp value is updated by the IIR LPF constituting the generation circuit 501. In S807, the correction circuit 502 corrects the black level of the pixel signal acquired by the photoelectric conversion unit 101 using the updated clamp value.

[0039] This operation makes it possible to correct horizontal stripe noise that occurs during one frame period when signals are read out from the pixels 102 arranged in the light-receiving region 201 with almost no delay. Furthermore, in this embodiment, a setting signal is used to detect changes in the state of the photoelectric conversion system in which the photoelectric conversion device 100 is arranged, and the setting for generating the clamp value is switched. This eliminates the need for many calculations, allowing the circuit scale of the generation circuit 501 and the selection signal generation circuit 702 to be small. In other words, the image quality of the resulting image can be improved while keeping the circuit scale small.

[0040] In addition, in the present embodiment, the case where there are two types of settings for generating the selection signal level and the clamp value has been described, but as described above, the correction section 150 may have settings for generating three or more selection signal levels and clamp values. Also, in the present embodiment, an example is shown in which the setting for generating the clamp value is switched only once during one frame period. However, this is not limited to this, and the selection signal level may be switched each time the state of the photoelectric conversion system changes, and the setting for generating the clamp value may be switched according to the selection signal level.

[0041] FIG. 9 is a diagram illustrating a modified example of the above-described detection unit 107. The above-described detection unit 107 detects a change in the state of the photoelectric conversion system based on a setting signal and changes the setting for generating a clamp value. However, the change in the setting for generating a clamp value is not limited to a change in the state of the photoelectric conversion system in which the photoelectric conversion device 100 is disposed. For example, when the power supply voltage in the photoelectric conversion device 100 supplied from the power supply unit 109 fluctuates, the level of the selection signal may be changed and the setting for generating a clamp value may be changed. The detection unit 900 shown in FIG. 9 detects fluctuations in the power supply voltage and generates a selection signal. The following description will focus on differences from the above-described configuration, and descriptions of similar configurations will be omitted as appropriate.

[0042] 9 is a block diagram of the detection unit 900. The detection unit 900 includes an AD conversion unit 901, a holding circuit 906, and a comparison circuit 907 instead of the signal detection circuit arranged in the detection unit 107. In the detection unit 900, the power supply voltage is AD converted by the AD conversion unit 901, and the AD-converted signal is held in the holding circuit 906. Next, the AD-converted signal and the AD-converted signal held in the holding circuit 906 are input to the comparison circuit 907, which determines whether or not there is a fluctuation in the power supply voltage. The determination result is supplied to the selection signal generation circuit 702, and the selection signal generation circuit 702 outputs a selection signal at a level according to the determination result to the signal processing unit 108.

[0043] The AD conversion unit 901 includes a ramp signal generation circuit 902, a comparison circuit 903, a counter 904, and a holding circuit 905. The AD conversion unit 901 converts the power supply voltage from an analog signal to a digital signal using, for example, slope-type AD conversion. The ramp signal generation circuit 902 and the counter 904 perform the same operations as the ramp signal generation circuit 301 and the counter 302 described above. The comparison circuit 903 receives a ramp signal and a power supply voltage, and outputs an inverted signal when the voltage of the ramp signal exceeds the power supply voltage. The holding circuit 905 receives a count value and an inverted signal, and holds the count value at the time the inverted signal is input as a digital signal.

[0044] The holding circuit 906 holds the AD-converted count value. In synchronization with the timing at which the next AD-converted count value is output from the AD conversion unit 901, the holding circuit 906 outputs the held count value. The comparison circuit 907 compares the count value output from the AD conversion unit 901 with the count value output from the holding circuit 906 to detect fluctuations in the power supply voltage. In other words, the detection unit 900 detects that the power supply voltage has fluctuated when the change in the value obtained by analog-to-digital conversion of the power supply voltage at a predetermined period exceeds a predetermined threshold.

[0045] When a fluctuation in the power supply voltage of the photoelectric conversion device is detected, the selection signal generation circuit 702 changes the level of the selection signal from level 0 to level 1. The selection signal output from the selection signal generation circuit 702 may have a configuration similar to that of the selection signal generation circuit 702 arranged in the detection unit 107 described above, and therefore individual explanations will be omitted. The selection signal is supplied to the generation circuit 501, and the setting for generating a clamp value in the generation circuit 501 is changed in accordance with the selection signal.

[0046] The detection unit 900 may be additionally provided in the photoelectric conversion device 100 shown in FIG. 1 . In this case, the setting for generating the clamp value changes in response to changes in the state of the photoelectric conversion system in which the photoelectric conversion device 100 is provided and changes in the power supply voltage in the photoelectric conversion device 100. Even when the detection unit 900 is additionally provided, the circuit configuration of the detection unit 900 is relatively small. Furthermore, the detection unit 900 may be provided in the photoelectric conversion device 100 instead of the detection unit 107. The detection unit 900 is a component of the correction unit 150 described above.

[0047] In this embodiment, the AD conversion unit 901 performs AD conversion on the power supply voltage using slope-type AD conversion, but this is not limiting. For example, the AD conversion unit 901 may perform AD conversion using other methods such as successive approximation type or ΔΣ type.

[0048] In addition, in this embodiment, the AD conversion unit 105 that performs AD conversion on the pixel signal and the AD conversion unit 901 that performs AD conversion on the power supply voltage are shown as separate configurations, but this is not limiting. For example, the AD conversion unit 105 may be configured to include the AD conversion unit 901 of the detection unit 900, and may share the ramp signal generation circuit and counter. This can further suppress an increase in circuit size due to the inclusion of the detection unit 900.

[0049] 10 to 16, further modifications of the photoelectric conversion device 100 described above will be described. In addition to the function of correcting the horizontal stripe noise described above, the photoelectric conversion device 100 of this embodiment has a function of correcting steps caused by pixel control and a function of correcting horizontal smear that occurs when strong light is incident on the photoelectric conversion unit 101. The following description will focus on differences from the configuration described above, and descriptions of configurations that may be similar will be omitted as appropriate. For example, in this embodiment as well, the photoelectric conversion device 100 may have the same configuration as shown in FIG. 1, and the photoelectric conversion unit 101 may have the same configuration as shown in FIG. 2.

[0050] Next, a description will be given of driving the pixels 102 using the vertical scanning unit 103 in this embodiment. The vertical scanning unit 103 is a driving circuit for driving the plurality of pixels 102 arranged in the photoelectric conversion unit 101.

[0051] The vertical scanning unit 103 performs electronic shutter scanning and readout scanning of the photoelectric conversion unit 101 in accordance with control signals supplied from the control unit 104. Electronic shutter scanning refers to an operation of sequentially releasing the reset state of the photoelectric conversion elements of the pixels 102 arranged in some or all of the pixel rows of the photoelectric conversion unit 101 and setting them into a charge accumulation state, thereby starting exposure. Readout scanning refers to an operation of sequentially outputting signals based on charges accumulated in the photoelectric conversion elements of the pixels 102 arranged in some or all of the pixel rows of the photoelectric conversion unit 101. Hereinafter, electronic shutter scanning and readout scanning will be collectively referred to as pixel control.

[0052] Fig. 10 shows an example of the configuration of a pixel 102 arranged in a photoelectric conversion unit 101 in this embodiment. The pixel 102 shown in Fig. 10 will be described as a pixel arranged in the mth column and the nth row. The pixel 102 includes a photoelectric conversion element PD, a floating diffusion (hereinafter sometimes simply referred to as "FD"), a transfer transistor M1, a reset transistor M2, an amplification transistor M3, a selection transistor M4, and a selection transistor M5.

[0053] The photoelectric conversion element PD is an element that performs photoelectric conversion and generates and accumulates electric charges corresponding to incident light. The photoelectric conversion element PD is, for example, a photodiode. The transfer transistor M1 transfers the electric charges accumulated in the photoelectric conversion element PD to FD, which is the input node of the amplification transistor M3. The FD holds the electric charges transferred via the transfer transistor M1. The reset transistor M2 resets the voltage of FD to a predetermined voltage. The amplification transistor M3 outputs a signal based on the electric potential of FD, which fluctuates according to the transferred electric charges, to the vertical output lines Vline1(m) and Vline2(m) of the mth column via the selection transistor M4 or the selection transistor M5.

[0054] The drains of the reset transistor M2 and the amplifier transistor M3 are electrically connected to the power supply line VCC. The source of the amplifier transistor M3 is electrically connected to the power supply unit 109 via the selection transistors M4 and M5 and the vertical output lines Vline1(m) and Vline2(m), and operates as a source follower circuit. In other words, the amplifier transistor M3 can output a signal according to the potential of the FD connected to its gate terminal.

[0055] Each transistor arranged in the pixel 102 may be configured as an N-channel transistor, as shown in Fig. 10. However, this is not limiting, and each transistor arranged in the pixel 102 may be configured as a P-channel transistor.

[0056] The signal PTX(n) is a signal that controls the transfer transistor M1 in the nth row and is input to the gate of the transfer transistor M1. The signal PRES(n) is a signal that controls the reset transistor M2 in the nth row and is input to the gate of the reset transistor M2. The signal PSEL1(n) is a signal that controls the select transistor M4 in the nth row and is input to the gate of the select transistor M4. The signal PSEL2(n) is a signal that controls the select transistor M5 in the nth row and is input to the gate of the select transistor M5. Each transistor is in a conductive state when the signal input to its gate is high level, and in a non-conductive state when the signal input to its gate is low level.

[0057] When reading pixel signals from the pixel 102, for example, N (noise) data is read out first, followed by S (signal) data. After the reset of the FD is released, the N data is read out by controlling the gate voltage of the selection transistor M4 or the selection transistor M5, thereby reading out the charge of the FD via the amplification transistor M3. When reading from the selection transistor M4, the gate voltage of the selection transistor M4 is set to high, and when reading from the selection transistor M5, the gate voltage of the selection transistor M5 is set to high. After the N data is read out, the S data is read out by transferring the charge of the photoelectric conversion element PD to the FD via the transfer transistor M1, and then controlling the gate voltage of the selection transistor M4 or the selection transistor M5, thereby reading out the charge of the FD via the amplification transistor M3. When reading from the selection transistor M4, the gate voltage of the selection transistor M4 is set to high, and when reading from the selection transistor M5, the gate voltage of the selection transistor M5 is set to high.

[0058] 11 is a schematic diagram showing an example of the configuration of the vertical scanning unit 103 and the photoelectric conversion unit 101 in this embodiment. The vertical scanning unit 103 outputs signals PTX(#), PRES(#), PSEL1(#), and PSEL2(#) (#: 1 to n). The signals PTX(k), PRES(k), PSEL1(k), and PSEL2(k) output from the vertical scanning unit 103 are supplied to pixels 102 (P(m, k) (k: 1 to n)) arranged in the kth row. The vertical scanning unit 103 controls the signals PTX(N), PRES(N), PSEL1(N), and PSEL2(N) (N: natural number) to perform electronic shutter scanning and readout scanning of the pixels 102 arranged in the Nth row.

[0059] FIG. 12 is a schematic diagram showing an example of the configuration of the photoelectric conversion unit 101 in this embodiment. The photoelectric conversion unit 101 includes pixels 102. The photoelectric conversion unit 101 also includes vertical output lines 111 connected to the pixels 102 arranged in each column. The selection transistor M4 arranged in the pixel 102 (P(m,n)) in the mth column and nth row is connected to the vertical output line 111 via a signal line sel1(n)_m, and the selection transistor M5 arranged in the pixel 102 (P(m,n)) is connected to the vertical output line 111 via a signal line sel2(n)_m. The vertical output line 111 is connected to the power supply unit 109. The vertical output line 111 is also connected to the AD conversion unit 105.

[0060] In this embodiment, six vertical output lines 111 are arranged for each column. In the configuration shown in Fig. 12, the six vertical output lines 111 connected to the pixels in the first column are represented as c1_vl# (#: 1 to 6), and the six vertical output lines 111 connected to the pixels in the mth column are represented as cm_vl#. The signal lines sel1(n)_m of each row and the vertical output lines cm_vl# (#: 1 to 6) are connected as follows:

[0061] The signal sel1(1)_k of the pixel 102 (P(k,1)) in the first row is connected to the vertical output line ck_vl1 (k:1 to m). The signal sel1(2)_k of the pixel 102 (P(k,2)) in the second row is connected to the vertical output line ck_vl2 (k:1 to m). The signal sel1(3)_k of the pixel 102 (P(k,3)) in the third row is connected to the vertical output line ck_vl3 (k:1 to m). Similarly, the signal line sel1(n)_m is connected to the vertical output line 111 every six rows. This connection does not necessarily have to be in row order, with the vertical output lines 111 being connected to the vertical output lines ck_vl1, ck_vl2, ck_vl3, ck_vl4, ck_vl5, and ck_vl6 (k:1 to m). It is sufficient that one of each of ck_vl1 to ck_vl6 is used in six consecutive lines.

[0062] 13 is a timing diagram showing an example of vertical scanning operation of the photoelectric conversion device 100 in this embodiment. First, pixel control of the photoelectric conversion device 100 will be described. As described above, pixel control includes electronic shutter scanning and readout scanning. In this embodiment, pixel signals of each pixel 102 from the first row to the Nth row (N: natural number) are acquired by pixel control. In addition, this embodiment will be described taking as an example a photoelectric conversion device 100 in which six vertical output lines 111 are arranged for each column.

[0063] When the reset of the photoelectric conversion element PD is released by electronic shutter scanning, the transfer transistor M1 of the pixel 102 is used, and the vertical scanning unit 103 controls the transfer transistor M1 via a signal PTX. When pixel signals are acquired by readout scanning, only the selection transistor M4 arranged in the pixel 102 is used. The pixel signals are read out via six vertical output lines 111 (vertical output lines cp_vl1, cp_vl2, cp_vl3, cp_vl4, cp_vl5, cp_vl6) arranged in each column. The first frame (time T1 to time T2) is an example in which electronic shutter scanning and readout scanning are each performed once.

[0064] At time T1, a readout operation is started. From time T1 to time T1a1, charges of the FDs of the pixels 102 in six rows from the first row to the sixth row are read out. At this time, the vertical scanning unit 103 controls the selection transistors M4 using a signal PSEL1(k) (k: 1 to 6), thereby reading out pixel signals via the selection transistors M4 arranged in the pixels 102. The pixel signals of the pixels 102 arranged in the first row are read out via the vertical output line cp_vl1, the pixel signals of the pixels 102 arranged in the second row are read out via the vertical output line cp_vl2, the pixel signals of the pixels 102 arranged in the third row are read out via the vertical output line cp_vl3, the pixel signals of the pixels 102 arranged in the fourth row are read out via the vertical output line cp_vl4, the pixel signals of the pixels 102 arranged in the fourth row are read out via the vertical output line cp_vl5, and the pixel signals of the pixels 102 arranged in the sixth row are read out via the vertical output line cp_vl6.

[0065] Next, from time T1a1 to time T1a2, the charges of the FDs of the pixels 102 in six rows from the 7th row to the 12th row are read out. At this time, the vertical scanning unit 103 controls the selection transistors M4 using a signal PSEL1(k) (k: 7 to 12), thereby reading out pixel signals via the selection transistors M4 arranged in the pixels 102. The pixel signals of the pixels 102 arranged in the 7th row are read out via the vertical output line cp_vl1, the pixel signals of the pixels 102 arranged in the 8th row are read out via the vertical output line cp_vl2, the pixel signals of the pixels 102 arranged in the 9th row are read out via the vertical output line cp_vl3, the pixel signals of the pixels 102 arranged in the 10th row are read out via the vertical output line cp_vl4, the pixel signals of the pixels 102 arranged in the 11th row are read out via the vertical output line cp_vl5, and the pixel signals of the pixels 102 arranged in the 12th row are read out via the vertical output line cp_vl6. Thereafter, sequential readout scanning is performed six rows at a time in synchronization with the horizontal synchronization signal HD shown in FIG.

[0066] Furthermore, in the first frame (time T1 to time T2), electronic shutter scanning is performed corresponding to the readout scanning of the second frame (time T2 to time T3). Electronic shutter scanning begins at time T1a3. Between time T1a3 and time T1a4, the reset of the photoelectric conversion elements PD of the pixels 102 in six rows from the first row to the sixth row is released. Thereafter, electronic shutter scanning is performed sequentially, six rows at a time, in synchronization with the horizontal synchronization signal HD. The second frame (time T2 to time T3) shows an example in which only readout scanning is performed.

[0067] The pixel control count shown in FIG. 13 indicates the sum of the number of pixel rows undergoing electronic shutter scanning and the number of pixel rows undergoing readout scanning during each period from time T1 to time T2. Because electronic shutter scanning and readout scanning overlap during the period from time T1a3 to time T1a7, the pixel control count differs from that during other periods. This causes fluctuations in the power supply voltage of the photoelectric conversion device 100, resulting in pixel control gaps in images using the resulting image data. To suppress this pixel control gap, the detection unit 107 may change the level of the selection signal from level 0 to level 1 when the number of pixels 102 driven by the vertical scanning unit 103 (drive circuit) among the multiple pixels 102 changes. The detection unit 107 sets the level of the selection signal to level 1 during the period from time T1a3 to time T1a4, when the pixel control count has changed. For example, in addition to the setting signal, information on the pixel control number (pixel control number signal shown in FIG. 13) may be supplied to the detection unit 107 from the control unit 104, which controls the operation of the vertical scanning unit 103, and the detection unit 107 may change the level of the selection signal in accordance with the pixel control number signal. The pixel control number signal may be supplied from the vertical scanning unit 103 to the detection unit 107. Also, for example, the control unit 104 may supply a selection signal to the generation circuit 501 in accordance with the pixel control number. In this case, the circuit configuration of the control unit 104 that supplies the selection signal in accordance with the pixel control number is included in the correction unit 150 described above.

[0068] In this embodiment, the start times of readout scanning and electronic shutter scanning are shown as time T1a1 to time T1a3, but each pixel control can start at any time. Depending on the scan start time of each pixel control, the position of the pixel row during the period in which electronic shutter scanning and readout scanning overlap can also differ.

[0069] 14 is a block diagram of an OB clamp processing unit 1000 for simultaneously correcting horizontal smear, correcting pixel control step differences, and correcting the horizontal stripe noise described above in this embodiment. In addition to the configuration of the OB clamp processing unit 500 described above, the OB clamp processing unit 1000 includes a line memory 1001, a smear detection unit 1002, and a selection signal generation circuit 1003.

[0070] The line memory 1001 is a memory that stores signals output from a plurality of pixels 102 arranged in the photoelectric conversion unit 101. The line memory 1001 holds pixel signals input to the OB clamp processing unit 1000 for at least one row.

[0071] The smear detection unit 1002 detects events that may cause horizontal bands in the pixel signals input to the OB clamp processing unit 1000. For example, in a CMOS image sensor, when strong light hits the light-receiving area 201, the signal levels of both the light-receiving area 201 and the HOB area 204 float, causing horizontal bands. This phenomenon is called horizontal smear.

[0072] The selection signal generation circuit 1003 includes the function of the selection signal generation circuit 702 arranged in the detection unit 107 described above. Therefore, in a photoelectric conversion device 100 including an OB clamp processing unit 1000, the detection unit 107 may include a signal detection circuit 701, and the selection signal generation circuit 702 may be omitted. The selection signal generation circuit 1003 is supplied with a signal from the signal detection circuit 701, the pixel control number signal described above, and a horizontal smear signal from the smear detection unit 1002. When the selection signal generation circuit 1003 detects a change in the state of the photoelectric conversion system, it changes the level of the selection signal from level 0 to level 1 in accordance with the signal supplied from the signal detection circuit 701. This suppresses horizontal stripe noise. Furthermore, when the number of pixels 102 driven by the vertical scanning unit 103 (drive circuit) changes, the selection signal generation circuit 1003 changes the level of the selection signal from level 0 to level 1 in accordance with the pixel control number signal. This suppresses pixel control gaps. Furthermore, when a smear (horizontal smear) occurs, the selection signal generation circuit 1003 changes the level of the selection signal from level 0 to level 1 in accordance with the horizontal smear signal supplied from the smear detection unit 1002. This suppresses the horizontal smear.

[0073] The generation circuit 501 generates correction data (clamp value) using the average value of the light-shielded signals supplied from the line memory 1001, using settings according to the selection signal supplied from the selection signal generation circuit 1003. The correction circuit 502 corrects the pixel signals of the pixels 102 arranged in the light-receiving region 201 supplied from the line memory 1001, according to the correction value generated by the generation circuit 501.

[0074] 15 is a block diagram of the smear detection unit 1002 disposed in the OB clamp processing unit 1000. The smear detection unit 1002 includes an exceed-threshold-level pixel count circuit 1101, an exceed-threshold-level pixel count holding circuit 1102, and a difference calculation circuit 1103. The smear detection unit 1002 counts the number of pixels 102 that output signal values exceeding the threshold among the pixel signals, calculates the difference between the count values in the previous and next pixel rows, and outputs a horizontal smear signal.

[0075] The exceed-threshold pixel count circuit 1101 counts the number of pixels 102 whose signal values exceed the threshold based on the pixel signals of the pixels 102 arranged in the light-receiving region 201. The exceed-threshold pixel count holding circuit 1102 holds the number of pixels 102 whose signal values exceed the threshold. The difference calculation circuit 1103 calculates the difference between the number of pixels whose signal values exceed the threshold in the previous row and the number of pixels whose signal values exceed the threshold in the current row. If the number of pixels whose signal values exceed the threshold in the current row is greater than a predetermined number compared to the previous row, the difference calculation circuit 1103 determines that horizontal smear has occurred. Furthermore, if the number of pixels whose signal values exceed the threshold in the current row is less than a predetermined number compared to the previous row, the difference calculation circuit 1103 determines that horizontal smear has disappeared. The difference calculation circuit 1103 changes the level of the horizontal smear signal when horizontal smear occurs or disappears. Depending on the signal level of the horizontal smear signal, the selection signal generation circuit changes the level of the selection signal from level 0 to level 1 while horizontal smear is detected. This enables correction to be performed to suppress the influence of horizontal smear on pixel signals.

[0076] As described above, the OB clamp processing unit 1000 includes a line memory 1001, a smear detection unit 1002, and a selection signal generation circuit 1003 in addition to the configuration of the OB clamp processing unit 500 described above. However, the selection signal generation circuit 1003 has a configuration similar to that of the selection signal generation circuit 702 disposed in the detection unit 107 described above. Furthermore, the circuit scale of the line memory 1001 and the smear detection unit 1002 is relatively small. In other words, it is possible to simultaneously correct horizontal smear, pixel control step differences, and horizontal stripe noise while suppressing an increase in circuit scale.

[0077] 16 is a flowchart showing signal processing by the OB clamp processing unit 1000 in this embodiment. The correction unit 150 corrects horizontal stripe noise and the like using steps S801 to S807 shown in FIG.

[0078] First, in S1601, row data, which is pixel signals of the pixels 102 arranged in each pixel row among the multiple pixels 102 arranged in the photoelectric conversion unit 101, is input to the line memory 1001 and the smear detection unit 1002. In S1602, the line memory 1001 holds the row data. In addition, in S1603, which can be performed in parallel with S1602, horizontal smear is detected by referring to the row data input to the smear detection unit 1002. In S1604, it is determined whether the input of the row data has ended. If the input has ended (Yes), the process proceeds to S1605. If the input is continuing (No), the process returns to input of the row data.

[0079] Upon transition to S1605, a selection signal is generated. As described above, the selection signal generation circuit 1003 is supplied with three types of detection signals: a signal from the signal detection circuit 701 corresponding to the setting signal, a pixel control number signal, and a horizontal smear signal. If none of the three detection signals indicate detection, that is, if the external device is operating normally or the number of driven pixels is not changing, or if no horizontal smear is detected, the selection signal generation circuit 1003 generates a signal of level 0 as the selection signal. On the other hand, if any of the three detection signals indicates detection, the selection signal generation circuit 1003 generates a signal of level 1 as the selection signal while the detection is being indicated.

[0080] In S1606, the selection circuit 602 of the generation circuit 501 determines the level of the selection signal. If the selection signal is level 0 (Yes), the process proceeds to S1607, where the generation circuit 501 is set according to setting 1. For example, a correction coefficient according to setting 1 is set in the attenuation circuit 603. If the selection signal is not level 0 (No), the process proceeds to S1608, where the generation circuit 501 is set according to setting 2. For example, a correction coefficient according to setting 2 is set in the attenuation circuit 603.

[0081] After the generation circuit 501 is set, in S1609, reading of the row data held in the line memory 1001 is started, and in S1610, the read row data (light-shielded signal) is used to update the clamp value by the IIR LPF constituting the generation circuit 501, as described above. In S1611, the correction circuit 502 corrects the black level of the pixel signal acquired by the photoelectric conversion unit 101, using the updated clamp value.

[0082] Through such operations, the photoelectric conversion device 100 (correction unit 150) of this embodiment can correct pixel control step and horizontal smear in addition to horizontal stripe noise. In this embodiment, an example has been shown in which the selection signal is generated by referring to three types of detection signals: a signal from the signal detection circuit 701 corresponding to the setting signal, a pixel control number signal, and a horizontal smear signal. However, this is not limiting, and the selection signal may be generated by referring to one or two of the three types of detection signals. For example, the photoelectric conversion device 100 (correction unit 150) may be configured so that the user can freely select which detection signal to refer to.

[0083] Furthermore, in the photoelectric conversion device 100 shown in FIGS. 10 to 16, the provision of a line memory 1001 increases the degree of freedom in correction for each pixel row. For example, a level 1 selection signal may be supplied to signals (row data) output from the plurality of pixels 102 during a detection period in which any of the three types of detection signals indicates detection and during at least one predetermined period before or after the detection period, and a clamp value (correction data) may be generated using a setting according to Setting 2. In the flow shown in FIG. 8, it is also possible to generate and correct clamp values according to Setting 2 for row data output from the plurality of pixels 102 during the detection period and the period after the setting period. On the other hand, in the configurations shown in FIGS. 10 to 16, it is possible to generate and correct clamp values according to Setting 2 for row data output from the plurality of pixels 102 during the detection period and the period before the setting period.

[0084] The correction unit 150 that performs the OB clamping process described in each of the above embodiments may be provided inside the photoelectric conversion device 100, as described above. However, this is not limited to this. For example, at least a portion of the configuration of the correction unit 150 may be arranged separately from the photoelectric conversion device 100 and the photoelectric conversion unit 101. The correction unit 150 may be a computer such as a personal computer that includes a processor (e.g., a CPU or an MPU) that is separate from the photoelectric conversion device 100. Furthermore, for example, the correction unit 150 may be a circuit such as an ASIC that realizes the above-mentioned functions.

[0085] FIG. 17 is a diagram showing an example of an arrangement of the blocks of the photoelectric conversion device 100 shown in FIG. 1 on a substrate such as a semiconductor. The photoelectric conversion device 100 may include a substrate 1301 and a substrate 1302 made of a semiconductor such as silicon. Components such as the detection unit 107, the correction unit 150 including the signal processing unit 108, the vertical scanning unit 103, the control unit 104, the AD conversion unit 105, the horizontal scanning unit 106, and the power supply unit 109 are arranged on the substrate 1301. The photoelectric conversion unit 101 is arranged on the substrate 1302. As shown in FIG. 17, at least a portion of the substrates 1301 and 1302 may be stacked. This configuration allows suitable processes to be selected for the analog unit including the photoelectric conversion unit 101 and the logic unit including the signal processing unit 108 when manufacturing the photoelectric conversion device 100. Using a manufacturing process suitable for each component can result in excellent characteristics for each component included in the photoelectric conversion device 100. As a result, the photoelectric conversion device 100 with improved image quality is obtained.

[0086] 18 shows the configuration of an imaging system 1400 as an example of equipment incorporating the above-described photoelectric conversion device 100. The imaging system 1400 includes a signal generation unit 1401, a signal correction unit 1402, a CPU 1403, an external input unit 1404, an optical system 1405, an image display unit 1406, a recording unit 1407, and a drive system 1408.

[0087] The signal correction unit 1402 may be the above-described detection unit 107 and signal processing unit 108. The signal generation unit 1401 may include the above-described vertical scanning unit 103, control unit 104, AD conversion unit 105, horizontal scanning unit 106, power supply unit 109, etc. Therefore, a configuration including the signal generation unit 1401 and the signal correction unit 1402 may be the above-described photoelectric conversion device 100.

[0088] In response to light incident through an optical system 1405 for making light incident on the photoelectric conversion unit 101 of the signal generation unit 1401, the signal generation unit 1401 performs photoelectric conversion to generate an analog image signal, and outputs image data by AD conversion. The output image data is corrected by a signal correction unit 1402 so that it can be output to and stored in a video display unit 1406 and a recording unit 1407. The video display unit 1406 displays an image using the display image data after the correction process. The recording unit 1407 stores the display image data. The CPU 1403 controls the various components of the imaging system 1400 described above. In other words, the CPU 1403 functions as a processing device that performs processing for displaying signals output from the signal generation unit 1401 and the signal correction unit 1402, which may constitute the photoelectric conversion device 100, on the video display unit 1406 and processing for storing the signals in the recording unit 1407. The drive system 1408 is arranged to, for example, operate the focus and aperture of the optical system 1405. The external input unit 1404 may be various buttons that the user uses to input and operate imaging conditions, shutter operation, etc. A touch panel may be provided as the video display unit 1406, and the video display unit 1406 may function as (a part of) the external input unit 1404. The present invention can also be realized by executing the following process: software (programs) that realize the functions of the above-described embodiments are supplied to a system or device via a network or various storage media, and one or more processors in the system or device read and execute the programs. The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

[0089] The disclosure of this specification includes the following photoelectric conversion devices and instruments.

[0090] (Item 1) A photoelectric conversion device comprising: a plurality of pixels; and a correction unit that corrects black levels of pixel signals output from the plurality of pixels in accordance with correction data, The correction unit during a period of one frame in which a signal for generating one image is obtained, when a state of a photoelectric conversion system in which the photoelectric conversion device is arranged changes, the level of the selection signal is changed from a first level to a second level; and A photoelectric conversion device, characterized in that a setting for generating the correction data is selected from a plurality of settings according to the level.

[0091] (Item 2) The photoelectric conversion device described in item 1, characterized in that the correction unit generates the correction data from a signal value based on a light-shielded signal output from a pixel arranged in a light-shielded region among the plurality of pixels, using a setting according to the level.

[0092] (Item 3) the correction unit includes a generation circuit for generating the correction data and a correction circuit for correcting the pixel signal in accordance with the correction data; the generating circuit includes a low-pass filter connected to an input node of the signal value; 3. The photoelectric conversion device according to item 2, wherein the setting is a setting of the amount of attenuation of the low-pass filter.

[0093] (Item 4) 4. The photoelectric conversion device according to item 3, wherein the tracking ability of the low-pass filter set according to the second level is higher than the tracking ability of the low-pass filter set according to the first level.

[0094] (Item 5) 5. The photoelectric conversion device according to item 3 or 4, wherein the correction unit generates the correction data using inter-pixel smoothing processing or inter-row smoothing processing.

[0095] (Item 6) the correction unit includes a detection unit that detects the change in the state and generates the selection signal; 6. The photoelectric conversion device according to any one of items 1 to 5, wherein the detection unit sets the level to the second level over a detection period during which the change in the state is detected.

[0096] (Item 7) The correction unit a memory for storing signals output from the plurality of pixels; 7. The photoelectric conversion device according to item 6, wherein the correction data is generated using settings according to the second level for signals output from the plurality of pixels during a detection period in which the detection unit detects a change in state and during at least one of a predetermined period before and after the detection period.

[0097] (Item 8) The photoelectric conversion device described in item 6 or 7, characterized in that the detection unit changes the level to the second level when at least one of the following cases is occurring: when communication is taking place between the photoelectric conversion device and a device in the photoelectric conversion system other than the photoelectric conversion device; and when a motor of a device in the photoelectric conversion system other than the photoelectric conversion device is driving.

[0098] (Item 9) 9. The photoelectric conversion device according to any one of items 6 to 8, wherein a signal indicating the change in state is supplied to the detection unit from a control circuit of the photoelectric conversion system.

[0099] (Item 10) 10. The photoelectric conversion device according to any one of items 1 to 9, wherein the second level signal includes a signal of a plurality of levels according to the change in the state.

[0100] (Item 11) The photoelectric conversion device described in any one of items 1 to 10, characterized in that when the state is a predetermined state, the correction unit maintains the level at the first level regardless of changes in the state.

[0101] (Item 12) Item 12. The photoelectric conversion device according to item 11, wherein the predetermined state includes a state in which the sensitivity of the photoelectric conversion system is set to a predetermined sensitivity or higher.

[0102] (Item 13) The photoelectric conversion device described in any one of items 1 to 12, characterized in that the correction unit changes the level from the first level to the second level when the power supply voltage of the photoelectric conversion device fluctuates.

[0103] (Item 14) The photoelectric conversion device described in item 13 is characterized in that the correction unit changes the level to the second level when a change in the value obtained by analog-to-digital conversion of the power supply voltage at a predetermined period exceeds a threshold value.

[0104] (Item 15) further comprising a drive circuit for driving the plurality of pixels; The photoelectric conversion device described in any one of items 1 to 14, characterized in that the correction unit changes the level from the first level to the second level when the number of pixels driven by the drive circuit among the plurality of pixels changes. (Item 16) 16. The photoelectric conversion device according to any one of items 1 to 15, wherein the correction unit changes the level from the first level to the second level when smear occurs.

[0105] (Item 17) A photoelectric conversion device comprising: a plurality of pixels; and a signal processing unit that corrects black levels of pixel signals output from the plurality of pixels in accordance with correction data, a detection unit that detects fluctuations in a power supply voltage of the photoelectric conversion device and generates a selection signal; the detection unit changes the level of the selection signal from a first level to a second level when detecting a fluctuation in the power supply voltage; The photoelectric conversion device, wherein the signal processing unit is configured to select a setting for generating the correction data from a plurality of settings in accordance with the level.

[0106] (Item 18) A photoelectric conversion device according to any one of items 1 to 17, a processing device that processes a signal output from the photoelectric conversion device; An apparatus characterized by comprising:

[0107] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0108] 100: photoelectric conversion device, 102: pixel, 150: correction unit

Claims

1. A photoelectric conversion device comprising: a plurality of pixels; and a correction unit that corrects black levels of pixel signals output from the plurality of pixels in accordance with correction data, The correction unit during a period of one frame in which a signal for generating one image is obtained, when a state of a photoelectric conversion system in which the photoelectric conversion device is arranged changes, the level of the selection signal is changed from a first level to a second level; and A photoelectric conversion device, characterized in that a setting for generating the correction data is selected from a plurality of settings according to the level.

2. The photoelectric conversion device according to claim 1, characterized in that the correction unit generates the correction data from a signal value based on a light-shielded signal output from a pixel among the plurality of pixels that is arranged in a light-shielded region, using a setting according to the level.

3. the correction unit includes a generation circuit for generating the correction data and a correction circuit for correcting the pixel signal in accordance with the correction data; the generating circuit includes a low-pass filter connected to an input node of the signal value; 3. The photoelectric conversion device according to claim 2, wherein the setting is a setting of an attenuation amount of the low-pass filter.

4. 4. The photoelectric conversion device according to claim 3, wherein the tracking ability of the low-pass filter set according to the second level is higher than the tracking ability of the low-pass filter set according to the first level.

5. 4. The photoelectric conversion device according to claim 3, wherein the correction unit generates the correction data using inter-pixel smoothing processing or inter-row smoothing processing.

6. the correction unit includes a detection unit that detects the change in the state and generates the selection signal; 2. The photoelectric conversion device according to claim 1, wherein the detection section sets the level to the second level over a detection period during which the change in state is detected.

7. The correction unit a memory for storing signals output from the plurality of pixels; The photoelectric conversion device according to claim 6, characterized in that the correction data is generated using settings according to the second level for signals output from the plurality of pixels during a detection period in which the detection unit detects a change in state and during at least one of a predetermined period before and after the detection period.

8. The photoelectric conversion device described in claim 6, characterized in that the detection unit changes the level to the second level when communication is taking place between the photoelectric conversion device and a device in the photoelectric conversion system other than the photoelectric conversion device, and when a motor of a device in the photoelectric conversion system other than the photoelectric conversion device is driving.

9. 7. The photoelectric conversion device according to claim 6, wherein a signal indicating the change in state is supplied to the detection unit from a control circuit of the photoelectric conversion system.

10. 2. The photoelectric conversion device according to claim 1, wherein the second level signal includes a signal of a plurality of levels according to the change in state.

11. 2. The photoelectric conversion device according to claim 1, wherein the correction section maintains the level at the first level when the state is a predetermined state, regardless of changes in the state.

12. 12. The photoelectric conversion device according to claim 11, wherein the predetermined state includes a state in which the sensitivity of the photoelectric conversion system is set to a predetermined sensitivity or higher.

13. 2. The photoelectric conversion device according to claim 1, wherein the correction section changes the level from the first level to the second level when a power supply voltage of the photoelectric conversion device fluctuates.

14. The photoelectric conversion device according to claim 13, characterized in that the correction unit changes the level to the second level when a change in the value obtained by analog-to-digital conversion of the power supply voltage at a predetermined period exceeds a threshold value.

15. further comprising a drive circuit for driving the plurality of pixels; 2. The photoelectric conversion device according to claim 1, wherein the correction unit changes the level from the first level to the second level when the number of pixels driven by the drive circuit among the plurality of pixels changes.

16. 2. The photoelectric conversion device according to claim 1, wherein the correction section changes the level from the first level to the second level when smear occurs.

17. A photoelectric conversion device comprising: a plurality of pixels; and a signal processing unit that corrects black levels of pixel signals output from the plurality of pixels in accordance with correction data, a detection unit that detects fluctuations in a power supply voltage of the photoelectric conversion device and generates a selection signal; the detection unit changes the level of the selection signal from a first level to a second level when detecting a fluctuation in the power supply voltage; The photoelectric conversion device, wherein the signal processing unit is configured to select a setting for generating the correction data from a plurality of settings in accordance with the level.

18. The photoelectric conversion device according to any one of claims 1 to 17, a processing device that processes a signal output from the photoelectric conversion device; An apparatus characterized by comprising:

Images