WO2023184265A1 - 固体拍摄装置、以及具备固体拍摄装置的拍摄装置 - Google Patents

固体拍摄装置、以及具备固体拍摄装置的拍摄装置 Download PDF

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WO2023184265A1
WO2023184265A1 PCT/CN2022/084177 CN2022084177W WO2023184265A1 WO 2023184265 A1 WO2023184265 A1 WO 2023184265A1 CN 2022084177 W CN2022084177 W CN 2022084177W WO 2023184265 A1 WO2023184265 A1 WO 2023184265A1
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signal
switching transistor
floating diffusion
photoelectric conversion
diffusion region
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PCT/CN2022/084177
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English (en)
French (fr)
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山下雄一郎
小林篤
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北京小米移动软件有限公司
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Priority to CN202280000999.2A priority Critical patent/CN117178564A/zh
Priority to JP2022525509A priority patent/JP2024517519A/ja
Priority to PCT/CN2022/084177 priority patent/WO2023184265A1/zh
Publication of WO2023184265A1 publication Critical patent/WO2023184265A1/zh

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  • the present invention relates to a solid-state imaging device and an imaging device including the solid-state imaging device.
  • the solid-state imaging device is a CMOS image sensor having a so-called Lateral Overflow Integration Capacitor (LOFIC).
  • LFIC Lateral Overflow Integration Capacitor
  • each pixel 501 of the solid-state imaging device 500 is equipped with: a photodiode ( A photoelectric conversion element) 502; a floating diffusion region 503 that converts the charge generated by the photodiode 502 into a voltage corresponding to the amount of the charge; and a lateral overflow storage capacitor 504 capable of accumulating the charge overflowing from the photodiode 502.
  • the reference numeral of each area in the potential diagram of FIG. 14 and FIG. 15 is the reference numeral of the corresponding structure in the equivalent circuit diagram of FIG. 14 followed by P.
  • reference signs t1 to t9 in FIG. 15 correspond to reference signs at drive time points t1 to t9 of each transistor shown in FIG. 16 .
  • each pixel 501 of the solid-state imaging element 500 when the amount of incident light to the photodiode 502 is large, charges overflowing from the photodiode 502 are accumulated in the lateral overflow storage capacitor 504 (refer to the reference numerals in FIG. 15 504P), by reading out the charge accumulated in the lateral overflow storage capacitor 504, a high dynamic range (ie, an input dynamic range above the capacitance of the photodiode 502) is achieved.
  • each pixel 501 when the amount of light incident on the photodiode 502 is large, that is, when the charge generated in the photodiode 502 exceeds its capacitance and overflows, the conversion gain of the floating diffusion region 503 is high. (that is, the switching transistor 505 disposed between the floating diffusion region 503 and the lateral overflow storage capacitor 504 is in an off state), the charge from the photodiode 502 is read (see t4 to t7 in FIG.
  • the charges that cannot be held by the floating diffusion region 503 among the charges that overflow from the photodiode 502 are accumulated in the lateral overflow storage capacitor 504.
  • the lateral overflow storage capacitor 504 is read out, After the charge accumulated in the storage capacitor 504 is overflowed, the lateral overflow storage capacitor 504 is read out through the reset signal of the pixel.
  • the reset level of the storage capacitor 504 is laterally overflowed before and after the amount of light when the charge starts to overflow from the photodiode 502.
  • the influence of thermal noise, dark current superimposed on the charge (signal) overflowing from the photodiode 502, and shot noise causes a discontinuity (gap) G with a large SN ratio as shown in FIG. 17 .
  • This discontinuity in the SN ratio is particularly noticeable in subjects with gradually changing hues, such as the sky, skin, clouds, etc., and is a major cause of deterioration in the image quality of the solid-state imaging element 500 .
  • Patent document 1 US2017/0099423.
  • an object of the present invention is to provide a solid-state imaging device and an imaging device including the solid-state imaging device that can achieve a high dynamic range and suppress degradation in image quality caused by a gap in the SN ratio.
  • the solid-state imaging device of the present invention includes:
  • Photoelectric conversion element which generates charge through photoelectric conversion according to the input light
  • a holding capacitor connected to the above-mentioned floating diffusion region and capable of accumulating the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a signal processing unit that processes a signal based on the voltage converted in the floating diffusion region
  • the signal processing unit has a plurality of processing units for signals read out using the holding capacitor.
  • the plurality of processing units may include a correlated double sampling unit and a correction unit that corrects the signal based on the voltage of the holding capacitor at reset.
  • the solid-state imaging device of the present invention includes:
  • Photoelectric conversion element which generates charge through photoelectric conversion according to the input light
  • a holding capacitor connected to the above-mentioned floating diffusion region and capable of accumulating the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a signal processing unit that processes a signal based on the voltage converted in the floating diffusion region
  • the above-mentioned signals with different conversion gains in the above-mentioned floating diffusion area are respectively subjected to correlated double sampling
  • the signal is corrected based on the voltage at the time of reset of the holding capacitor.
  • the above-mentioned solid-state imaging device may include:
  • a first switching transistor connecting the above-mentioned photoelectric conversion element and the above-mentioned floating diffusion area
  • a third switching transistor is connected to the holding capacitor and the reset potential
  • the floating diffusion area is connected to the reset potential via the second switching transistor and the third switching transistor in turn,
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned on by the control unit from the state where the first to third switching transistors are turned off is used as a signal.
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned off by the control unit is used as a second signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off by the control unit is used as a third signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor is turned on by the control unit is used as a fourth signal
  • a signal based on the voltage of the floating diffusion region when the third switching transistor is turned on and off when the second switching transistor is turned on by the control unit is used as the fifth signal.
  • An output signal output from the solid-state imaging device to the outside can be generated based on the first to fifth signals.
  • the above-mentioned correlated double sampling is respectively included in the signal processing to obtain the first differential signal based on the difference between the above-mentioned fourth signal and the above-mentioned first signal, and the signal processing to obtain the second differential signal based on the difference between the above-mentioned third signal and the above-mentioned second signal.
  • Correction of the voltage at the time of reset of the holding capacitor is included in the signal processing for obtaining a third differential signal based on the difference between the fourth signal and the fifth signal.
  • the above-mentioned solid-state imaging device may include:
  • a storage unit that stores a first threshold value set based on at least the capacitance of the photoelectric conversion element and a second threshold value set based on at least the capacitance of the floating diffusion region
  • the value of the third differential signal is compared with the second threshold.
  • the first differential signal is output as the output signal
  • the second differential signal is output as the output signal.
  • the solid-state imaging device may include:
  • a second storage capacitor that, unlike the first storage capacitor as the above-mentioned storage capacitor, can accumulate the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a first switching transistor connecting the above-mentioned photoelectric conversion element and the above-mentioned floating diffusion region
  • the floating diffusion area is connected to the second holding capacitor via the second switching transistor and the fourth switching transistor in sequence, and is connected to the reset potential via the second switching transistor, the fourth switching transistor, and the third switching transistor in sequence. connect,
  • the first holding capacitor is connected to the reset potential via the fourth switching transistor and the third switching transistor in sequence,
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned on by the control unit from the state where the first to fourth switching transistors are turned off is used as a signal.
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned off by the control unit is used as a second signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off by the control unit is used as a third signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor is turned on by the control unit is used as a fourth signal
  • the voltage of the floating diffusion region based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor and the fourth switching transistor are turned on by the control unit are obtained. signal as the fifteenth signal,
  • the voltage of the floating diffusion region will be based on the voltage of the floating diffusion region when the third switching transistor is turned on and off when the second switching transistor and the fourth switching transistor are turned on by the control unit. signal as the sixteenth signal,
  • a signal based on the voltage of the floating diffusion region when the fourth switching transistor is turned off in a state where the second switching transistor is turned on by the control unit is used as the seventeenth signal
  • An output signal output from the solid-state imaging device to the outside is generated based on the first to fourth signals and the fifteenth to seventeenth signals.
  • the above-mentioned correlated double sampling is respectively included in the signal processing to obtain the first differential signal based on the difference between the above-mentioned fourth signal and the above-mentioned first signal, and the signal processing to obtain the second differential signal based on the difference between the above-mentioned third signal and the above-mentioned second signal.
  • the correction of the voltage at reset of the holding capacitor is included in the signal processing to obtain a third differential signal based on the difference between the fourth signal and the seventeenth signal, and the signal processing based on the fifteenth signal and the sixteenth signal.
  • the fourth differential signal is obtained by differential signal processing.
  • the above-mentioned solid-state imaging device may be any solid-state imaging device.
  • a storage unit stores a first threshold set based on at least the capacitance of the photoelectric conversion element, a second threshold set based on at least the capacitance of the floating diffusion region, and at least the capacitance of the floating diffusion region and the first holding The third threshold set by the capacitor,
  • the value of the third differential signal is compared with the second threshold.
  • the first differential signal is output as the output signal
  • the second differential signal is output as the output signal.
  • the first holding capacitance is smaller than the second holding capacitance.
  • an imaging device includes any one of the solid-state imaging devices described above.
  • FIG. 1 is a diagram showing the structure of a solid-state imaging device according to the first embodiment.
  • FIG. 2 is an equivalent circuit diagram of a pixel included in the solid-state imaging device.
  • FIG. 3 is a diagram showing a driving time point of the pixel and a pixel signal corresponding to the driving time point.
  • FIG. 4 is a diagram showing a driving time point of the pixel and a pixel signal corresponding to the driving time point.
  • FIG. 5 is a diagram showing a driving time point of the pixel and a pixel signal corresponding to the driving time point.
  • FIG. 6 is a data flow chart of the signal processing unit included in the solid-state imaging device.
  • FIG. 7 is a graph showing the input-output characteristics of the above-mentioned pixels.
  • FIG. 8 is a graph showing the SN ratio of the above-mentioned pixels.
  • FIG. 9 is a diagram showing the structure of a solid-state imaging device according to a second embodiment.
  • FIG. 10 is an equivalent circuit diagram of a pixel included in the solid-state imaging device.
  • FIG. 11 is a timing chart of the above-mentioned pixels.
  • FIG. 12 is a data flow chart of the signal processing unit included in the solid-state imaging device.
  • FIG. 13 is a graph showing the SN ratio of the above-mentioned pixels.
  • FIG. 14 is an equivalent circuit diagram and a potential diagram of a pixel included in a conventional solid-state imaging device.
  • FIG. 15 is a potential diagram showing the flow of signal charges in the above-described pixel.
  • FIG. 16 is a diagram showing the driving timing of the above-mentioned pixels.
  • FIG. 17 is a graph showing the SN ratio of the above-mentioned pixels.
  • Photoelectric conversion element which generates charge through photoelectric conversion according to the input light
  • a holding capacitor connected to the above-mentioned floating diffusion region and capable of accumulating the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a signal processing unit that processes a signal based on the voltage converted in the floating diffusion region
  • the signal processing unit has a plurality of processing units for signals read out using the holding capacitor.
  • the holding capacitor accumulates overflowing charges in a range in which the amount of input light is large, thereby achieving a high dynamic range, and at the same time, by outputting the amount of light (charge generated by the photoelectric conversion element) according to the amount of light input to the photoelectric conversion element
  • the signal generated by the signal processing of the amount appropriately suppresses gaps at discontinuous positions (light amounts) in the graph of the SN ratio, thereby suppressing degradation in image quality due to the gaps. Details are as follows.
  • the holding capacitor Even if the charge generated by the photoelectric conversion element due to the input of light exceeds the capacitance of the photoelectric conversion element and overflows, the holding capacitor accumulates the overflowed charge and reads out the charge generated by the photoelectric conversion element from the floating diffusion region. This holds the charge accumulated in the capacitor, thereby achieving an input dynamic range (ie, high dynamic range) above the capacitance of the photoelectric conversion element.
  • the plurality of processing units may include a correlated double sampling unit and a correction unit that corrects the signal based on the voltage of the holding capacitor when it is reset.
  • the signal for reading out the charge generated by the photoelectric conversion element using the holding capacitor is subjected to correlated double sampling, so that the signal is not affected by the dark current generated during the accumulation of charge in the photoelectric conversion element or the thermal noise generated by the holding capacitor. impact or the impact is sufficiently suppressed.
  • the read signal of the charge generated by the photoelectric conversion element can be reset based on the storage capacitor using a storage capacitor in which the overflowed charges are accumulated.
  • the corrected signal is affected by dark current generated by the photoelectric conversion element or thermal noise generated by the holding capacitor.
  • the readout signal (number of charges) is large for the above-mentioned amount of overflowing light, the influence of dark current or thermal noise on this signal is relatively small, thereby suppressing discontinuous positions in the graph of the SN ratio. (for example, refer to the gaps G1 and G2 shown in FIG. 8) (the above-mentioned position where the overflow starts).
  • the solid-state imaging device of this embodiment includes:
  • Photoelectric conversion element which generates charge through photoelectric conversion according to the input light
  • a holding capacitor connected to the above-mentioned floating diffusion region and capable of accumulating the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a signal processing unit that processes a signal based on the voltage converted in the floating diffusion region
  • the above-mentioned signals with different conversion gains in the above-mentioned floating diffusion area are respectively subjected to correlated double sampling
  • the signal is corrected based on the voltage at the time of reset of the holding capacitor.
  • the holding capacitor accumulates the overflowed charge in a range in which the amount of input light is large (that is, the second state in which the charge generated by inputting the light to the photoelectric conversion element overflows from the photoelectric conversion element). Achieving a high dynamic range while appropriately suppressing discontinuous positions in the graph of the SN ratio ( light amount), thereby suppressing degradation in image quality due to the gap. Details are as follows.
  • the holding capacitor Even if the charge generated by the photoelectric conversion element due to the input of light exceeds the capacitance of the photoelectric conversion element and overflows, the holding capacitor accumulates the overflowed charge and reads out the charge (signal) generated by the photoelectric conversion element from the floating diffusion region. The charge accumulated in the holding capacitor is read out at this time, thereby achieving an input dynamic range (ie, high dynamic range) that is greater than the capacitance of the photoelectric conversion element.
  • the readout signal in the state in which charge overflows from the photoelectric conversion element can be corrected based on the voltage at the time of reset of the holding capacitor
  • the readout signal is affected by Influences such as dark current generated by the photoelectric conversion element or thermal noise generated by the holding capacitor.
  • the signal (number of charges) to be read out is relatively large for the amount of overflow light, the influence of dark current or thermal noise on this signal is relatively small, thereby suppressing discontinuous positions in the graph of the SN ratio. (for example, refer to the gap G2 in FIG. 8 ) (the above-mentioned position where overflow starts).
  • the above-mentioned solid-state imaging device may include:
  • a first switching transistor connecting the above-mentioned photoelectric conversion element and the above-mentioned floating diffusion area
  • a third switching transistor is connected to the holding capacitor and the reset potential
  • the floating diffusion area is connected to the reset potential via the second switching transistor and the third switching transistor in turn,
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned on by the control unit from the state where the first to third switching transistors are turned off is used as a signal.
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned off by the control unit is used as a second signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off by the control unit is used as a third signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor is turned on by the control unit is used as a fourth signal
  • An output signal output from the solid-state imaging device to the outside can be generated based on the first to fifth signals.
  • the above-mentioned correlated double sampling is respectively included in the signal processing to obtain the first differential signal based on the difference between the above-mentioned fourth signal and the above-mentioned first signal, and the signal processing to obtain the second differential signal based on the difference between the above-mentioned third signal and the above-mentioned second signal.
  • Correction of the voltage at the time of reset of the holding capacitor is included in the signal processing for obtaining a third differential signal based on the difference between the fourth signal and the fifth signal.
  • the above-mentioned solid-state imaging device may include:
  • a storage unit that stores a first threshold value set based on at least the capacitance of the photoelectric conversion element and a second threshold value set based on at least the capacitance of the floating diffusion region
  • the value of the third differential signal is compared with the second threshold.
  • the first differential signal is output as the output signal
  • the second differential signal is output as the output signal.
  • the signal processing section selects a signal to be output using two threshold values, thereby more reliably performing signal processing based on the amount of light input to the photoelectric conversion element (the amount of charge generated by the photoelectric conversion element), that is, by correlated double sampling Switching between signal processing and signal processing that performs correction based on the voltage at the time of reset of the holding capacitor, selection of signals generated by these processes, etc.
  • the above-mentioned solid-state imaging device may include:
  • a second storage capacitor that, unlike the first storage capacitor as the above-mentioned storage capacitor, can accumulate the above-mentioned charge overflowing from the above-mentioned photoelectric conversion element;
  • a first switching transistor connecting the above-mentioned photoelectric conversion element and the above-mentioned floating diffusion area
  • the floating diffusion area is connected to the second holding capacitor via the second switching transistor and the fourth switching transistor in sequence, and is connected to the reset potential via the second switching transistor, the fourth switching transistor, and the third switching transistor in sequence. connect,
  • the first holding capacitor is connected to the reset potential via the fourth switching transistor and the third switching transistor in sequence,
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned on by the control unit from the state where the first to fourth switching transistors are turned off is used as a signal.
  • a signal based on the voltage of the floating diffusion region when the second switching transistor is turned off by the control unit is used as a second signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off by the control unit is used as a third signal
  • a signal based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor is turned on by the control unit is used as a fourth signal
  • the voltage of the floating diffusion region based on the voltage of the floating diffusion region when the first switching transistor is turned on and off when the second switching transistor and the fourth switching transistor are turned on by the control unit are obtained. signal as the fifteenth signal,
  • the voltage of the floating diffusion region will be based on the voltage of the floating diffusion region when the third switching transistor is turned on and off when the second switching transistor and the fourth switching transistor are turned on by the control unit. signal as the sixteenth signal,
  • a signal based on the voltage of the floating diffusion region when the fourth switching transistor is turned off in a state where the second switching transistor is turned on by the control unit is used as the seventeenth signal
  • An output signal output from the solid-state imaging device to the outside is generated based on the first to fourth signals and the fifteenth to seventeenth signals.
  • the photoelectric conversion element by obtaining seven signals (the first to fourth signals and the fifteenth to seventeenth signals) in the primary charge accumulation (primary light input) of the photoelectric conversion element, it is possible to adjust the amount of the input light (by photoelectric conversion) according to the amount of the input light.
  • the amount of charge generated by the element should be subjected to either signal processing by correlated double sampling or signal processing by correcting the voltage at reset based on the holding capacitor.
  • two storage capacitors (a first storage capacitor and a second storage capacitor) capable of accumulating charges overflowing from the photoelectric conversion element are provided, and the number of storage capacitors used is adjusted according to the amount of charges generated by the photoelectric conversion element. It is possible to suppress deterioration in image quality due to thermal noise and other holding capacitors. That is, since the larger the storage capacitor is, the larger the thermal noise and the like that causes noise are.
  • the capacitor is configured to ensure the same capacitance (the total capacitance of the first storage capacitor and the second storage capacitor), thereby suppressing deterioration in image quality caused by thermal noise and other storage capacitors.
  • the above-mentioned correlated double sampling is respectively included in the signal processing to obtain the first differential signal based on the difference between the above-mentioned fourth signal and the above-mentioned first signal, and the signal processing to obtain the second differential signal based on the difference between the above-mentioned third signal and the above-mentioned second signal.
  • the correction of the voltage at reset of the holding capacitor is included in the signal processing to obtain a third differential signal based on the difference between the fourth signal and the seventeenth signal, and the signal processing based on the fifteenth signal and the sixteenth signal.
  • the fourth differential signal is obtained by differential signal processing.
  • the above-mentioned solid-state imaging device may include a storage unit
  • the storage unit stores a first threshold set based on at least the capacitance of the photoelectric conversion element, a second threshold set based on at least the capacitance of the floating diffusion region, and at least the capacitance of the floating diffusion region and the first holding capacitance setting.
  • the third threshold is determined,
  • the value of the third differential signal is compared with the second threshold.
  • the first differential signal is output as the output signal
  • the second differential signal is output as the output signal.
  • the signal processing section selects a signal to be output using three threshold values, thereby more reliably performing signal processing according to the amount of light input to the photoelectric conversion element (the amount of charge generated by the photoelectric conversion element), that is, by correlated double sampling Switching between signal processing and signal processing that performs correction based on the voltage at the time of reset of the holding capacitor, selection of signals generated by these processes, etc.
  • the first storage capacitance is preferably smaller than the second storage capacitance.
  • the relative magnitude of noise (noise caused by the holding capacitance such as thermal noise) with respect to the signal corresponding to the number of charges read out from the holding capacitor is suppressed, that is, the above-mentioned noise
  • the impact on image quality is suppressed. Therefore, by reducing the first holding capacitor used when the amount of charge from the photoelectric conversion element is small, the noise generated by the first holding capacitor when only the first holding capacitor is used is suppressed, and the amount of charge from the photoelectric conversion element is increased.
  • the second holding capacitor used when the number of charges increases and the impact of the above-mentioned noise on the image quality is relatively small can achieve a high dynamic range and appropriately suppress the degradation of image quality caused by the holding capacitor.
  • an imaging device includes any one of the solid-state imaging devices described above.
  • the photographing device of this embodiment is, for example, a smartphone or a digital camera.
  • the solid-state imaging device of this embodiment is an embedded imaging device and includes a solid-state imaging element (SOLID STATE IMAGE SENSOR) including a CMOS image sensor and the like.
  • the solid-state imaging device 1 includes at least a solid-state imaging device.
  • the solid-state imaging device 1 of this embodiment includes a CMOS image sensor (solid-state imaging device), a signal processing unit 7 , and a memory 8 .
  • a solid-state imaging device 1 incorporated in the imaging device includes a pixel array unit 2 , a vertical driving unit 3 , a plurality of column signal processing units 4 , a horizontal driving unit 5 , a control unit 6 and a signal processing unit. 7.
  • the solid-state imaging device 1 is provided with a memory 8 capable of storing signals and the like processed by the signal processing unit 7 .
  • at least the pixel array unit 2 , the vertical drive unit 3 , the plurality of column signal processing units 4 , the horizontal drive unit 5 and the control unit 6 constitute a CMOS image sensor.
  • the pixel array section 2, the vertical driving section 3, the column signal processing section 4, the horizontal driving section 5, the control section 6 and the signal processing section 7 are arranged on the same semiconductor substrate or on a plurality of electrically connected semiconductor substrates.
  • the signal processing unit 7 and the memory 8 may be arranged on the semiconductor substrate on which the pixel array unit 2 , the vertical driving unit 3 , the column signal processing unit 4 , the horizontal driving unit 5 and the control unit 6 are arranged, or they may be arranged on different substrates. wait. That is, the arrangement positions of the signal processing unit 7 and the memory 8 are not limited.
  • the pixel array unit 2 has a plurality of pixels 10 arranged two-dimensionally in a matrix.
  • Each of these plurality of pixels 10 is an effective unit pixel, and the effective unit pixel has a photoelectric conversion element 11 that can photoelectrically convert input light (incident light) and internally accumulate an amount corresponding to the input light. amount of signal charge (charge), and outputs the accumulated signal charge.
  • the details of the specific structure of each pixel 10 will be described later.
  • the plurality of pixels 10 may include dummy unit pixels having a structure without a photoelectric conversion element, light-shielding unit pixels that block the input of light from the outside by blocking the light-receiving surface, and the like.
  • the light-shielding unit pixel has the same structure as the effective unit pixel except that it has a structure that blocks the light-receiving surface.
  • the pixel array unit 2 has a plurality of row signal lines 21 arranged in each row and extending in the row direction, and a plurality of column signal lines arranged in each column and extending in the column direction with respect to the matrix-like pixel arrangement. twenty two.
  • Each of the plurality of row signal lines 21 is connected to the vertical driving section 3
  • each of the plurality of column signal lines 22 is connected to the corresponding column signal processing section 4 .
  • the vertical driving unit 3 is composed of, for example, a shift register, selects a predetermined row signal line 21, supplies a pulse (signal) for driving the pixel 10 to the selected row signal line 21, and drives the pixel 10 in row units.
  • the vertical drive section 3 sequentially selects and scans each pixel 10 of the pixel array section 2 in the vertical direction in row units, and transmits a signal generated based on the amount of light input to the photoelectric conversion element 11 of each pixel 10 through the column signal line 22 The pixel signal of electric charge is supplied to the column signal processing section 4 .
  • Each of the plurality of column signal processing units 4 is disposed in each column of the pixels 10 and performs signal processing such as noise reduction on a pixel signal output from one row of pixels 10 for each pixel column.
  • Each column signal processing unit 4 of this embodiment performs signal processing such as correlated double sampling (CDS) and A/D (Analog/Digital) conversion to remove fixed pattern noise inherent to pixels.
  • CDS correlated double sampling
  • A/D Analog/Digital
  • the horizontal drive unit 5 is composed of, for example, a shift register. By sequentially outputting horizontal scanning pulses, each of the plurality of column signal processing units 4 is sequentially selected, and the pixel signals processed by each column signal processing unit 4 are sequentially output to Signal processing section 7.
  • the control unit 6 controls the operations of each unit of the solid-state imaging device 1 . Specifically, the control unit 6 receives an input clock signal and data for instructing an operation mode and the like, and outputs data such as internal information of the solid-state imaging device 1 . In detail, the control unit 6 generates a clock signal or a control signal that is a reference for the operations of the vertical drive unit 3, the column signal processing unit 4, the horizontal drive unit 5, etc. based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock signal, and generates The generated clock signal or control signal is output to the vertical driving section 3, the column signal processing section 4, the horizontal driving section 5, and the like.
  • the signal processing unit 7 performs various signal processing such as arithmetic processing on the pixel signals output from each column signal processing unit 4 .
  • the signal processing unit 7 has a calculation unit 71 that calculates pixel signals, a determination unit 72 that determines the calculation result of the calculation unit, and a selector 73 that outputs a signal based on the determination result of the determination unit (see FIG. 6 ).
  • the signal processing unit 7 of this embodiment is a DSP (Digital Signal Processor; digital signal processor).
  • DSP Digital Signal Processor; digital signal processor
  • the specific arrangement position of the signal processing unit 7 is not limited.
  • the signal processing unit 7 is arranged at a different position from the CMOS image sensor.
  • the entire structure of the signal processing unit 7 may be arranged (mounted) on the CMOS image sensor, or the signal processing unit 7 may be arranged (mounted) on the CMOS image sensor. Part of the configuration is configured in the CMOS image sensor.
  • the memory 8 is a line memory, a frame memory, a FIFO, etc., and can store the pixel signal output from the signal processing section 4 of each column. The specific structure of this memory 8 will be described later.
  • the pixel 10 is provided with: a photoelectric conversion element 11 that generates signal charges through photoelectric conversion based on input light; and a floating diffusion region 12 that converts the signal charges generated by the photoelectric conversion element 11 into a voltage signal corresponding to the amount of the signal charges ( voltage); and a holding capacitor 13, which is connected to the floating diffusion region 12 and can accumulate signal charges overflowing from the photoelectric conversion element 11.
  • the photoelectric conversion element 11 of this embodiment is, for example, a photodiode.
  • the pixel 10 is provided with: a transfer transistor (first switching transistor) 14 that connects the photoelectric conversion element 11 and the floating diffusion region 12; a holding switching transistor (second switching transistor) 15 that connects the floating diffusion region 12 and the holding capacitor 13;
  • the reset transistor (third switching transistor) 16 is connected to the holding capacitor 13 and the reset power supply (reset potential) VDD1;
  • the amplification transistor 17 is to amplify the voltage signal of the floating diffusion area 12;
  • the selection transistor 18 is connected to the amplification transistor 17 and column signal lines 22.
  • a plurality of row signal lines 21 are wired for each pixel row. Furthermore, various drive signals ⁇ TX, ⁇ S, ⁇ RES, and ⁇ SEL are supplied from the vertical driving unit 3 to each pixel 10 via the row signal line 21 .
  • the above-mentioned driving signals ⁇ TX, ⁇ S, ⁇ RES and ⁇ SEL are the above-mentioned pulses.
  • the floating diffusion region 12 performs charge-voltage conversion of the signal charge generated by the photoelectric conversion element 11 into a voltage signal and outputs it.
  • the floating diffusion area 12 of this embodiment is also connected to the reset power supply VDD1 via the holding switching transistor 15 and the reset transistor 16 in sequence.
  • the holding capacitor 13 is a capacitor, and is connected to the floating diffusion region 12 via the holding switching transistor 15 as described above, and is also connected to the reset power supply VDD1 via the reset transistor 16 .
  • the drive signal ⁇ TX is applied to the gate electrode of the transfer transistor 14 .
  • This drive signal ⁇ TX is output from the vertical drive unit 3 based on a signal (command) from the control unit 6 .
  • the drive signal ⁇ TX becomes Hi (that is, when the transfer transistor 14 is turned on)
  • the transfer gate of the transfer transistor 14 becomes on
  • the signal charge accumulated in the photoelectric conversion element 11 is transferred to the floating state via the transfer transistor 14 Diffusion area 12.
  • the drive signal ⁇ TX becomes Low, the transfer transistor 14 is turned off.
  • the drive signal ⁇ S is applied to the gate electrode of the holding switching transistor 15 .
  • This drive signal ⁇ S is output from the vertical drive unit 3 based on the signal from the control unit 6 .
  • the driving signal ⁇ S becomes Hi (that is, the holding switching transistor 15 is turned on)
  • the holding gate of the holding switching transistor 15 becomes turned on, and signal charges can move from the floating diffusion region 12 to the holding capacitor 13 .
  • the drive signal ⁇ S becomes Low, the switching transistor 15 is kept turned off.
  • the holding gate (potential barrier) of the holding switching transistor 15 is adjusted so that signal charges are accumulated in the holding capacitor 13 when they overflow from the photoelectric conversion element 11 .
  • the drive signal ⁇ RES is applied to the gate electrode of the reset transistor 16 .
  • This drive signal ⁇ RES is output from the vertical drive unit 3 based on the signal from the control unit 6 .
  • the drive signal ⁇ RES becomes Hi (that is, the reset transistor 16 is turned on)
  • the reset gate of the reset transistor 16 becomes on
  • the floating diffusion region is formed according to the drive signal ⁇ S applied to the gate electrode of the holding switching transistor 15 12 and the potential of the holding capacitor 13 or the potential of the holding capacitor 13 is reset to the level (reset level) of the reset power supply (reset potential) VDD1.
  • the drive signal ⁇ RES becomes Low, the reset transistor 16 is turned off.
  • the gate electrode is connected to the floating diffusion region 12, and the drain electrode is connected to the power supply VDD2.
  • This amplification transistor 17 is an input portion of a readout circuit (so-called source follower circuit SF) that reads out the voltage of the floating diffusion region 12 as a pixel signal. That is, the amplification transistor 17 connects its source electrode to the column signal line 22 via the selection transistor 18 , thereby constituting a constant current source and a source follower circuit SF connected to one end of the column signal line 22 .
  • the selection transistor 18 is connected to the source electrode of the amplification transistor 17 and the column signal line 22 .
  • the drive signal ⁇ SEL is applied to the gate electrode of the selection transistor 18 .
  • This drive signal ⁇ SEL is output from the vertical drive unit 3 based on the signal from the control unit 6 .
  • the drive signal ⁇ SEL becomes Hi (that is, the selection transistor 18 is turned on)
  • the selection gate of the selection transistor 18 becomes on
  • the pixel 10 becomes the selected state.
  • the pixel signal output from the amplification transistor 17 is output to the column signal line 22 via the selection transistor 18 .
  • the drive signal ⁇ SEL becomes Low, the selection transistor 18 is turned off.
  • FIGS. 3 to 5 show the drive signal (pulse of the control signal) of the pixel 10 and the corresponding output voltage (pixel signal) appearing on the column signal line 22.
  • the drive signal ⁇ SEL , ⁇ RES, ⁇ S and ⁇ TX are all the same, and Vout in each figure represents the output voltage.
  • the transfer transistor 14 is turned off while the floating diffusion region 12 is connected to the reset power supply VDD1, whereby the photoelectric conversion element 11 becomes a floating state, and the signal charge generated by the input of light starts to accumulate in the photoelectric conversion element 11.
  • the holding switching transistor 15 and the reset transistor 16 are respectively turned off, whereby the floating diffusion region 12 and the holding capacitor 13 are also brought into a floating state.
  • the floating diffusion region 12 and the holding capacitor 13 can hold (accumulate) the overflowed signal charges.
  • the transfer transistor 14 , the holding switching transistor 15 and the reset transistor 16 are turned off, the pixel signal of the pixel 10 is read from time t02 after the predetermined accumulation period ⁇ T has passed after the transfer transistor 14 is turned off.
  • the control unit 6 (specifically, the vertical drive unit 3 receiving instructions from the control unit 6) changes the drive signal ⁇ SEL to Hi. Therefore, when the selection transistor 18 is turned on, the pixel 10 is connected to the column signal line 22 .
  • the control unit 6 changes the drive signal ⁇ S to Hi and turns on the holding switching transistor 15 , whereby the floating diffusion region 12 and the holding capacitor 13 are electrically connected.
  • the thermal noise more specifically, thermal noise charge
  • the dark current generated during the accumulation of signal charges in the photoelectric conversion element 11 more specifically, the dark current generated by the dark current
  • Dark current charge and so on are mixed, and the voltage of the floating diffusion region 12 (retaining capacitor reference potential) at this time is read from the source follower circuit SF after a limited time from the time t03 when it appears in the source follower circuit SF, and at A After /D conversion, it is stored in the memory 8 as the first signal (pixel signal).
  • the column signal processing unit 4 stores the first signal in the memory 8 in a state after A/D conversion (that is, a state converted into a digital signal).
  • A/D conversion that is, a state converted into a digital signal.
  • Each subsequent process may be performed while the pixel signal (voltage of the floating diffusion region 12 ) read out from the source follower circuit SF is maintained as an analog signal.
  • the pixel signals (second to fifth signals) read out from the source follower circuit SF at subsequent time points are also the same.
  • the control unit 6 changes the drive signal ⁇ S to Low, turns off the holding switching transistor 15, and electrically disconnects the floating diffusion region 12 and the holding capacitor 13.
  • the potential of the floating diffusion area 12 (floating diffusion area reference potential) is read out from the source follower circuit SF, and after A/D conversion, is stored in the memory 8 as a second signal (pixel signal).
  • This second signal also includes a dark current component stored in the holding switching transistor 15 .
  • the control unit 6 changes the drive signal ⁇ TX to Hi, turns on the transfer transistor 14, and after the photoelectric conversion element 11 transfers the signal charges accumulated during the accumulation period ⁇ T to the floating diffusion region 12, the control unit 6 switches the drive signal ⁇ TX to Hi. ⁇ TX becomes Low, turning off the transfer transistor 14.
  • This signal is read out from the source follower circuit SF at time t06, and is stored in the memory 8 as a third signal (pixel signal) after A/D conversion.
  • the control unit 6 changes the drive signal ⁇ S to Hi and turns on the holding switching transistor 15, thereby turning on the floating diffusion region 12 and the holding capacitor 13, the control unit 6 changes the driving signal ⁇ TX to Hi again and Low turns the transfer transistor 14 on and off.
  • the voltage of the floating diffusion region 12 at this time is read out from the source follower circuit SF, and is stored in the memory 8 as a fourth signal (pixel signal) after A/D conversion.
  • the control unit 6 changes the drive signal ⁇ RES to Hi and turns on the reset transistor 16, thereby connecting the floating diffusion area 12 and the holding capacitor 13 to the reset power supply (reset potential) VDD1, causing the floating diffusion area 12 to and the signal charge of the holding capacitor 13 are all initialized (reset).
  • the initialized voltage (reset level) of the floating diffusion region 12 and the holding capacitor 13 is read out from the source follower circuit SF, and is stored in the memory 8 as a fifth signal (pixel signal) after A/D conversion.
  • the signal charge generated by the light input to the pixel 10 (photoelectric conversion element 11) during the accumulation period ⁇ T does not exceed the capacitance that the photoelectric conversion element 11 can hold, and photoelectricity is processed only in the floating diffusion region 12
  • signal charges accumulated (held) in the conversion element 11 in the case of the first premise: see FIG. 3
  • signal charges lower than the processing limit of the floating diffusion area 12 are transferred to the floating diffusion area 12
  • the pixel signal (voltage of the floating diffusion region 12) read out from the source follower circuit SF changes accordingly (refer to Vout).
  • the pixel signal (voltage of the floating diffusion area 12: refer to Vout in FIG. 3) does not exceed the range of the A/D conversion (input dynamic range). That is, in the floating diffusion area 12, the signal is correctly maintained without overflow.
  • the fourth signal (pixel) read out from the source follower circuit SF signal) becomes a signal corresponding to the voltage of the floating diffusion region 12 in a state where the signal charge transferred from the photoelectric conversion element 11 is divided by the capacitance ratio of the floating diffusion region 12 and the holding capacitor 13 .
  • the signal processing section 7 subtracts the second signal from the third signal, so that the final signal (signal Z) photoelectrically converted by the pixel 10 is restored. Details are as follows.
  • the second signal includes the dark current generated in the floating diffusion region 12 and the holding capacitor 13 during the accumulation of signal charges in the photoelectric conversion element 11 (that is, during the accumulation period ⁇ T), and the thermal noise generated after reset at time t01 All, but correlated double sampling is possible by transferring signal charges from the photoelectric conversion element 11 to the floating diffusion region 12 thereby generating a third signal to be added to the second signal.
  • the dark current and heat are determined based on the performance determined by the CMRR (Common Mode Rejection Ratio) of the circuit.
  • the noise is almost completely removed in practical applications, as a result of which the final signal (signal Z) photoelectrically converted by the pixel 10 is recovered.
  • the other signals (the first signal, the fourth signal, and the fifth signal) stored in the memory 8 do not require the recovery of the final signal (the signal Z).
  • the signal charge generated by the light input to the pixel 10 (photoelectric conversion element 11) during the accumulation period ⁇ T does not exceed the capacitance that the photoelectric conversion element 11 can hold, and therefore does not overflow from the photoelectric conversion element 11, but exceeds the float.
  • the amount that the diffusion region 12 can handle is an amount that can be handled in a state where the floating diffusion region 12 and the holding capacitor 13 are electrically connected (in the case of the second premise: see FIG. 4 )
  • the third signal obtained at time t06 is a signal in a saturated state of the floating diffusion area 12 .
  • the signal processing section 7 subtracts the first signal from the fourth signal, thereby restoring the final signal (signal Y) photoelectrically converted by the pixel 10 . Details are as follows.
  • the first signal includes all of the dark current generated in the floating diffusion region 12 and the holding capacitor 13 during the accumulation of signal charges in the photoelectric conversion element 11, and the thermal noise generated after reset at time t01, but all the signal charges are transferred from the
  • the photoelectric conversion element 11 is transmitted to the floating diffusion area 12 in a state of being electrically connected to the holding capacitor 13 to generate a fourth signal to be added to the first signal, allowing correlated double sampling to be performed.
  • the dark current and thermal noise are almost completely reduced in practical applications. is removed, with the result that the final signal (signal Y) photoelectrically converted by the pixel 10 is restored.
  • the other signals (the second signal, the third signal and the fifth signal) stored in the memory 8 do not require the recovery of the final signal (signal Y).
  • the signal charge generated by the light input to the pixel 10 (photoelectric conversion element 11) during the accumulation period ⁇ T does not exceed the capacitance that the photoelectric conversion element 11 can hold, and therefore does not overflow from the photoelectric conversion element 11 to the holding capacitor 13.
  • the floating diffusion region 12 and the holding capacitor 13 are electrically connected to a handleable amount (in the case of the third premise: see FIG. 5 )
  • the signal overflowing from the photoelectric conversion element 11 Charge has been accumulated in the floating diffusion region 12 and the holding capacitor 13, thus corresponding to the same dark current and thermal noise as the first premise or the second premise and the output (pixel signal) of the overflowed signal charge as the first signal and the second premise.
  • the signal is stored in memory 8.
  • the transfer transistor 14 is turned on, and the signal charge accumulated in the photoelectric conversion element 11 is transferred from the photoelectric conversion element 11 to the floating diffusion region 12.
  • the third signal is photoelectric A signal indicating the saturated state of the switching element 11 .
  • the fifth signal obtained at time t08 is a reset level (reset signal of the pixel 10 ) regardless of the signal charge accumulated in the photoelectric conversion element 11 .
  • the signal processing section 7 subtracts the fifth signal and the like from the fourth signal (refer to the third signal processing of FIG. 6 ), thereby restoring the final signal (signal X) photoelectrically converted by the pixel 10 . Details are as follows.
  • the first signal is a signal including signal charges overflowing from the photoelectric conversion element 11 and therefore cannot be used as a reference reset level. Therefore, after the signal including all the signal charges generated by the photoelectric conversion element 11 during the accumulation period ⁇ T is read out from the source follower circuit SF, the pixel 10 is re-initialized at time t08, and the pixel signal read out after the re-initialization is used as the reset voltage. level (fifth signal) is recorded in the memory 8.
  • This reset level (fifth signal) is different from the reset level when the fourth signal is read from the first signal because the floating diffusion region 12 and the holding capacitor 13 are in a floating state after changing to the low impedance state at time t08 . Therefore, in the fifth signal, the influence of thermal noise determined by the capacitance value and temperature, Boltzmann's constant, and the influence of dark current and its shot noise during the accumulation period ⁇ T cannot be ignored.
  • the capacitance of the photoelectric conversion element 11 is set to be sufficiently larger (in the example of this embodiment, 2 times or more) than the capacitance (processed signal amount) of the floating diffusion region 12, the floating diffusion region 12 and the holding capacitance
  • the combined capacitance (processed signal amount) of 13 is set to be sufficiently larger than the capacitance of the photoelectric conversion element 11 (1.5 times or more in the example of this embodiment), so that the aforementioned thermal noise, the dark current during the accumulation period ⁇ T and its The shot noise becomes sufficiently smaller than the shot noise contained in the signal related to the signal charges accumulated in the photoelectric conversion element 11 .
  • This can sufficiently suppress the influence on the image quality of the final image in a smartphone, camera, etc. equipped with the solid-state imaging device 1 .
  • the signal processing unit 7 subtracts the fifth signal and the like from the fourth signal (refer to the third signal processing in FIG. 6 ), thereby restoring the final signal (signal X) photoelectrically converted by the pixel 10 .
  • the signal processing unit 7 performs signal processing (calculation) based on the above premises (first to third premises). Details are as follows.
  • each pixel signal (first to fifth signals) is read out from a certain pixel 10 , the pixel signal is stored in the memory 8 , and the conversion result of each pixel 10 is processed one by one or in parallel in the signal processing unit 7 and pipeline processing, etc.
  • the memory 8 of this embodiment has: a first signal storage unit 801 that stores a first signal; a second signal storage unit 802 that stores a second signal; and a third signal storage unit 803. It stores the third signal; the fourth signal storage part 804, which stores the fourth signal; the fifth signal storage part 805, which stores the fifth signal; and the offset storage part 820, which stores the offset (arbitrary) taking into account the dark current. ) value; a first gain storage section 831 that stores a first gain coefficient that adjusts the signal so that the signal output relative to the light input in the solid-state imaging device 1 changes monotonically and continuously; a second gain storage section 832, which stores a second gain coefficient used to adjust the charge-to-voltage conversion gain.
  • the memory 8 further includes a first threshold storage unit 841 that stores a first threshold value, and a second threshold storage unit 842 that stores a second threshold value.
  • This first threshold is a value set based on at least the capacitance of the photoelectric conversion element 11 .
  • the first threshold is a value set in consideration of detection variation or individual variation of the photoelectric conversion element 11 in the maximum signal amount determined by the capacitance of the photoelectric conversion element 11 .
  • the first threshold in this embodiment is a value smaller than the light amount when the signal amount of the signal Y in FIG. 7 is saturated (the boundary position between the second section and the third section) and the sum is set near the light amount when the signal Y is saturated.
  • the value of the semaphore corresponding to the intersection point of the vertical line (single-dash line).
  • FIG. 7 is a graph showing the input-output characteristics when the horizontal axis is the amount of light input to the pixel and the vertical axis is the signal amount of the signals X, Y, and Z (pixel signal amount).
  • the second threshold value is a value set based on at least the capacitance of the floating diffusion region 12 .
  • the second threshold value is a value set in consideration of detection variation or individual variation of the photoelectric conversion element 11 in the maximum signal amount determined by the capacitance of the floating diffusion region 12 .
  • the second threshold in this embodiment is a value smaller than the light amount when the signal amount of the signal Z is saturated (the boundary position between the first section and the second section), and is a vertical line set in the vicinity of the light amount when the signal Z is saturated. The value of the semaphore corresponding to the intersection point of the (single-dot-dash line).
  • the calculation unit 71 calculates the third signal stored in the third signal storage unit 803 of the memory 8 .
  • the difference between the signal and the second signal stored in the second signal storage unit 802 is calculated as a signal (second differential signal) Z (first signal processing), and the fourth signal stored in the fourth signal storage unit 804 of the memory 8 is
  • the difference of the first signal stored in the signal storage unit 801 is multiplied by the second gain coefficient stored in the second gain storage unit 832 to calculate the signal (first differential signal) Y (second signal processing), and then the memory 8
  • the first gain coefficient stored in the storage unit 831 is used to calculate the signal (third differential signal) X (third signal processing).
  • the judgment unit 72 first compares the signal X with the first threshold stored in the first threshold storage unit 841. When the signal X is greater than the first threshold, , indicating that the signal X is output to the selector 73.
  • the determination unit 72 instructs the signal Z to be output to the selector 73 .
  • the selector 73 When the above-described arbitrary instruction (output instruction instruction) is input to the selector 73 through the judgment unit 72, the selector 73 outputs any one of the signal X, the signal Y, and the signal Z (processing result) based on the input instruction.
  • the signal amount of the signal Y decreases as the input light amount increases in the fourth interval.
  • the signal amount of the signal Z is saturated in the second interval, and decreases as the light amount increases in the third interval and onward.
  • the judgment section 72 when the signal Y or the signal Z is used as the first condition of the conditional branch of the judgment, the pixel signal amount that satisfies the condition (that is, the input light amount that becomes the same signal amount) exists when the input light amount is small.
  • the judgment unit 72 of this embodiment uses the signal X in the interval in which the signal amount does not decrease as the initial judgment criterion, and thereafter uses the signal Y to prevent the above-mentioned judgment error from occurring.
  • the above-mentioned judgment sequence is not necessary.
  • the signal Y or the like may also be used for the judgment.
  • the above solid-state imaging device 1 includes: a photoelectric conversion element 11 that generates signal charges through photoelectric conversion based on input light; a floating diffusion region 12 that converts signal charges into a voltage corresponding to the amount of the signal charges; and a holding capacitor 13 , which is connected to the floating diffusion area 12 and is capable of accumulating signal charges overflowing from the photoelectric conversion element 11 ; and a signal processing section 7 which processes a signal based on the voltage converted by the floating diffusion area 12 . Furthermore, the signal processing unit 7 has a plurality of processing units that use the pixel signals read out from the storage capacitor 13 .
  • This solid-state imaging device 1 accumulates signals overflowing from the photoelectric conversion element 11 via the holding capacitor 13 in a range (for example, the third section in FIG. 7 ) in which the amount of light input to the photoelectric conversion element 11 (input light amount) is large. charge, thereby achieving a high dynamic range while appropriately suppressing the SN ratio in the graph
  • the gaps between the discontinuous positions (light amounts) (the vertical intervals between the discontinuous portions in the graph of FIG. 8 ) G1 and G2 , thereby suppressing the distortion of the final image due to the camera or the like in which the solid-state imaging device 1 is arranged.
  • the gaps G1 and G2 cause a degradation in image quality. Details are as follows.
  • the holding capacitor 13 Even if the signal charge generated by the photoelectric conversion element 11 due to the input of light exceeds the capacitance of the photoelectric conversion element 11 and overflows, the holding capacitor 13 will accumulate the overflow signal charge and read out the signal charge from the floating diffusion region 12 by the photoelectric conversion element. The signal charges accumulated in the holding capacitor 13 are read out when the signal charges generated by the photoelectric conversion element 11 are generated, thereby achieving an input dynamic range (ie, a high dynamic range) that is greater than the capacitance of the photoelectric conversion element 11 .
  • an input dynamic range ie, a high dynamic range
  • the plurality of processing units of the signal processing unit 7 include correlated double sampling and correction of the signal based on the voltage when the holding capacitor 13 is reset.
  • the signal in which the signal charge generated by the photoelectric conversion element 11 is read out using the holding capacitor 13 is subjected to correlated double sampling (for example, a process of subtracting the second signal from the third signal by the arithmetic unit 71 (refer to the first step of FIG. 6 signal processing) or processing of subtracting the first signal from the fourth signal (refer to the second signal processing of FIG. 6)), etc., thereby the signal is not affected by the process of accumulating signal charges in the photoelectric conversion element 11 (i.e., The influence of dark current generated during the accumulation period ⁇ T or thermal noise generated by the holding capacitor 13 is sufficiently suppressed.
  • the signal charges generated by the photoelectric conversion element 11 can be read out using the storage capacitor 13 in which the overflowed signal charges are accumulated. 13. Correction of the voltage at the time of reset (for example, processing of subtracting the fifth signal from the fourth signal by the calculation unit 71 (refer to the third signal processing of FIG. 6)), etc., but the corrected signal is received by the photoelectric conversion element 11 or the thermal noise generated by the holding capacitor 13, etc.
  • the signal processing unit 7 of this embodiment is in the first state in which signal charges generated by light input to the photoelectric conversion element 11 during the accumulation period ⁇ T do not overflow from the photoelectric conversion element 11 (that is, the amount of input light is as shown in FIG. 7 (the range to the left of the light amount corresponding to the first threshold, the range to the left of the gap G2 in Figure 8), convert pixel signals with different gains in the floating diffusion area 12, and perform correlated double sampling respectively.
  • the light When the signal charge generated by being input to the photoelectric conversion element 11 overflows from the photoelectric conversion element 11 in the second state (that is, the input light amount is from the light amount corresponding to the first threshold to the third interval and the fourth interval in FIG. 7
  • the range of the boundary (the range from the gap G2 to the right end of the drawing of the SN ratio in FIG. 8 ) is corrected based on the voltage at the time of reset of the holding capacitor for the above-mentioned pixel signal.
  • the signal charges generated by the photoelectric conversion element 11 are read out from the floating diffusion region 12 with different conversion gains (for example, high conversion gain, that is, reading in a state where the floating diffusion region 12 is electrically disconnected from the holding capacitor 13
  • Correlated double sampling can be performed both for reading out and low conversion gain, that is, reading when the floating diffusion region 12 and the holding capacitor 13 are electrically connected). Therefore, the pixel signal read out above is not affected by the dark current generated in the process of accumulating signal charges in the photoelectric conversion element 11 or the thermal noise generated by the holding capacitor, or the influence is sufficiently suppressed. This suppresses the gap G1 at the discontinuous position (the position where the conversion gain is switched) in the graph of the SN ratio (see FIG. 8 ).
  • the state in which signal charges overflow from the photoelectric conversion element 11 can be corrected based on the voltage at the time of reset of the storage capacitor 13 (when the reset transistor 16 is turned on and off at time t08 in FIGS. 3 to 5 ).
  • the readout signal will be affected by dark current generated by the photoelectric conversion element 11 or thermal noise generated by the holding capacitor 13 .
  • the pixel signal (number of charges) to be read out is relatively large with regard to the amount of overflow light, the influence of dark current or thermal noise on the pixel signal is relatively small, thereby suppressing the inconsistency in the graph of the SN ratio.
  • Gap G2 at the continuous position (the above-mentioned position where overflow starts) (see FIG. 8 ).
  • the gaps G1 and G2 at discontinuous positions in the graph of the SN ratio are respectively suppressed (in other words, made smaller). Therefore, the gap between the solid-state imaging device 1 and the solid-state imaging device 1 where the solid-state imaging device 1 is arranged is effectively suppressed.
  • the gaps G1 and G2 cause a degradation in image quality in the final image of the camera or the like of the imaging device 1 .
  • the solid-state imaging device 1 of this embodiment includes a transfer transistor (first switching transistor) 14 that connects the photoelectric conversion element 11 and the floating diffusion region 12; and a holding switching transistor (second switching transistor) 15 that connects The floating diffusion region 12 and the holding capacitor 13; the reset transistor (third switching transistor) 16, which connects the holding capacitor 13 and the reset power supply (reset potential) VDD1; and the control part 6, which controls each of the switching transistors 14, 15, 16.
  • the floating diffusion area 12 is also connected to the reset power supply VDD1 via the holding switching transistor 15 and the reset transistor 16 in sequence.
  • the signal processing unit 7 of the solid-state imaging device 1 starts from the state in which the transfer transistor 14, the holding switch transistor 15, and the reset transistor 16 are off.
  • the signal based on the voltage of the floating diffusion region 12 when the transistor 15 is turned on by the control part 6 is used as the first signal.
  • the signal based on the floating diffusion region 12 when the switching transistor 15 is turned off by the control part 6 is maintained.
  • the voltage signal is used as the second signal.
  • the signal based on the voltage of the floating diffusion region 12 when the transfer transistor 14 is turned on and off by the control part 6 is used as the third signal.
  • the signal based on the voltage of the floating diffusion region 12 when the transfer transistor 14 is turned on and off in the state where the holding switching transistor 15 is turned on by the control part 6 is used as the fourth signal.
  • the holding When the signal based on the voltage of the floating diffusion region 12 is used as the fifth signal when the reset transistor 16 is turned on and off while the switching transistor 15 is turned on by the control unit 6, a solid-state image is generated based on the first to fifth signals.
  • the device 1 outputs output signals (signal X, signal Y, signal Z) to the outside.
  • the correlated double sampling is included in the operation (third signal processing) of obtaining the signal Y based on the difference between the fourth signal and the first signal, and the operation based on the third signal and the second signal.
  • the difference of the signal Z is obtained in the operation (first signal processing).
  • correction based on the voltage at the time of reset of the holding capacitor 13 is included in the operation (second signal processing) of obtaining the signal X based on the difference between the fourth signal and the fifth signal.
  • the solid-state imaging device 1 of this embodiment includes a memory (storage unit) 8 that stores a first threshold value set based on the capacitance of the photoelectric conversion element 11 and a first threshold value set based on the capacitance of the floating diffusion region 12 . Second threshold. Furthermore, the signal processing unit 7 compares the value of the signal X with the first threshold, and when the value of the signal X is greater than the first threshold, outputs the signal As a result, when the value of the signal As a result of comparing the value of the signal Y with the second threshold, when the value of the signal Y is equal to or less than the second threshold, the signal Z is output as the output signal.
  • a memory (storage unit) 8 that stores a first threshold value set based on the capacitance of the photoelectric conversion element 11 and a first threshold value set based on the capacitance of the floating diffusion region 12 . Second threshold.
  • the signal processing unit 7 compares the value of the signal X with the first threshold, and when the value of the signal X
  • the signal processing section 7 selects (judges) the signals X, Y, and Z to be output using the two threshold values, thereby more reliably performing a process based on the amount of light input to the photoelectric conversion element 11 (the signal charge generated by the photoelectric conversion element 11 amount) of signal processing, that is, switching between signal processing by correlated double sampling and signal processing by correction based on the voltage at the time of reset of the holding capacitor 13, or selection of signals generated by these processes, etc.
  • the solid-state imaging device 1 of this embodiment does not use the holding capacitor 13 for the double conversion gain ( Dual Conversion Gain), but using it as a lateral overflow storage capacitor, by specifying it in the signal processing section 7 at a new pixel driving time point (ie, a new driving time point of each transistor 14 to 16 in the pixel 10) signal processing, thereby achieving an input dynamic range (high dynamic range) larger than the capacitance of the photoelectric conversion element 11, and at the same time reducing the lateral overflow of the resulting pixel signal caused by the dark current accumulated in the storage capacitor (holding capacitor 13) and the impact caused by reset noise.
  • a new pixel driving time point ie, a new driving time point of each transistor 14 to 16 in the pixel 10
  • this effect can be enhanced by making the capacitance (saturation charge) of the photoelectric conversion element 11 larger than the capacitance of the floating diffusion region 12 .
  • FIGS. 9 to 13 a second embodiment of the present invention will be described with reference to FIGS. 9 to 13 .
  • the same structures as those in the above-described first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted, and only different structures will be described in detail. .
  • the imaging device of this embodiment is, for example, a smartphone or a digital camera.
  • the solid-state imaging device 1 is embedded in the imaging device and includes a CMOS image sensor (solid-state imaging element).
  • the solid-state imaging device 1A incorporated in this imaging device has the same configuration as the solid-state imaging device 1 of the first embodiment. That is, as shown in FIG. 9 , the solid-state imaging device 1A includes a pixel array unit 2, a vertical drive unit 3, a plurality of column signal processing units 4, a horizontal drive unit 5, a control unit 6, a signal processing unit 7, and a memory 8A.
  • the pixel array unit 2 includes a plurality of pixels 10A two-dimensionally arranged in a matrix
  • the signal processing unit 7 includes a calculation unit 71A, a determination unit 72A, and a selector 73 (see FIG. 12).
  • the pixel 10A includes a photoelectric conversion element 11 , a floating diffusion region 12 , a first storage capacitor 13 having the same configuration (capacitance) as the storage capacitor of the first embodiment, and a second storage capacitor 13A that is different from the first storage capacitor 13 .
  • the pixel 10A is provided with: a transfer transistor (first switching transistor) 14 that connects the photoelectric conversion element 11 and the floating diffusion region 12; and a first holding switching transistor (second switching transistor) 15 that connects the floating diffusion region 12 and the holding capacitor. 13; Reset transistor (third switching transistor) 16, which connects the second holding capacitor 13A and the reset power supply (reset potential) VDD1; second holding switching transistor (fourth switching transistor) 15A, which connects the first holding capacitor 13 and the third switching transistor.
  • two holding capacitors 13A an amplification transistor 17, which amplifies the voltage signal of the floating diffusion region 12; and a selection transistor 18, which connects the amplification transistor 17 and the column signal line 22.
  • the floating diffusion region 12 converts the signal charge generated by the photoelectric conversion element 11 into a voltage signal and outputs the signal.
  • the floating diffusion region 12 of this embodiment is connected to the second holding capacitor 13A through the first holding switching transistor 15 and the second holding switching transistor 15A in sequence.
  • the floating diffusion area 12 is connected to the reset power supply VDD1 via the first holding switching transistor 15 , the second holding switching transistor 15A and the reset transistor 16 in sequence.
  • the first storage capacitor 13 and the second storage capacitor 13A are each a capacitor, and like the storage capacitor 13 of the first embodiment, each can accumulate signal charges overflowing from the photoelectric conversion element 11 . Specifically, when signal charges overflow from the photoelectric conversion element 11 , the signal charges are first accumulated in the first holding capacitor 13 . Furthermore, after the first holding capacitor 13 also overflows, the overflowed signal charge is accumulated in the second holding capacitor 13A.
  • the first holding capacitor 13 is also connected to the reset power supply VDD1 via the second holding switching transistor 15A and the reset transistor 16 in sequence.
  • the first storage capacitor 13 is smaller than the second storage capacitor 13A.
  • the capacitance of the signal charge that the first holding capacitor 13 can accumulate (hold) is smaller than the capacitance of the signal charge that the second holding capacitor 13A can accumulate (hold).
  • the drive signal ⁇ S is applied to the gate electrode of the first holding switching transistor 15 .
  • This drive signal ⁇ S is output from the vertical drive unit 3 based on the signal from the control unit 6 .
  • the driving signal ⁇ S becomes Hi (that is, the first holding switching transistor 15 is turned on)
  • the first holding gate of the first holding switching transistor 15 becomes turned on, and the signal charge from the floating diffusion region 12 can move to The first holding capacitor 13.
  • the drive signal ⁇ S becomes Low
  • the first holding switch transistor 15 is turned off.
  • the holding gate (potential barrier) of the first holding switching transistor 15 is adjusted so that signal charges are accumulated in the first holding capacitor 13 when they overflow from the photoelectric conversion element 11 .
  • the first holding switch transistor 15 of this embodiment has the same structure as the holding switching transistor of the first embodiment.
  • the drive signal ⁇ S1 is applied to the gate electrode of the second holding switching transistor 15A.
  • This drive signal ⁇ S1 is output from the vertical drive unit 3 based on the signal from the control unit 6 .
  • the driving signal ⁇ S1 becomes Hi (that is, the second holding switching transistor 15A is turned on)
  • the second holding gate of the second holding switching transistor 15A becomes on. If the first holding switching transistor 15 is turned on, then Signal charges from the floating diffusion region 12 may move to the second holding capacitor 13A. Furthermore, when the drive signal ⁇ S1 becomes Low, the second holding switch transistor 15A is turned off.
  • the second holding gate (potential barrier) of the second holding switching transistor 15A is adjusted so that the signal charge overflows from the photoelectric conversion element 11 and also from the first holding capacitor 13 When it overflows, it is accumulated in the second holding capacitor 13A.
  • the reset transistor 16 of this embodiment when the drive signal ⁇ RES becomes Hi and the reset transistor 16 is turned on, based on the drive signal ⁇ S applied to the gate electrode of the first hold switch transistor 15 and the drive signal ⁇ S applied to the second hold switch transistor 15
  • the potential of the capacitor 13A is reset to the level (reset level) of the reset power supply (reset potential) VDD1.
  • the transfer transistor 14, the first holding switching transistor 15, the second holding switching transistor 15A, and the reset transistor 16 are turned on, and the floating diffusion region 12 and the first holding capacitor are turned on. 13 and the second holding capacitor 13A become the reset level.
  • the transfer transistor 14 is turned off while the floating diffusion region 12 is connected to the reset power supply VDD1, whereby the photoelectric conversion element 11 becomes a floating state, and the signal charge generated by the input of light starts to accumulate in the photoelectric conversion element 11.
  • the transfer transistor 14 is turned off (in detail, with a slight delay)
  • the first holding switching transistor 15, the second holding switching transistor 15A, and the reset transistor 16 are turned off respectively. Therefore, the floating diffusion region 12, the first holding switching transistor 15A, and the reset transistor 16 are turned off respectively.
  • the capacitor 13 and the second holding capacitor 13A also become a floating state. Therefore, when signal charges overflow (overflow) from the photoelectric conversion element 11 , the floating diffusion region 12 , the first holding capacitor 13 and the second holding capacitor 13A can hold (accumulate) the overflowing signal charges.
  • the pixel signal of the pixel 10 is read out from time t02 after the predetermined accumulation period ⁇ T has elapsed.
  • the control unit 6 changes the drive signal ⁇ SEL to Hi to change the selected state.
  • the transistor 18 is turned on, the pixel 10 is connected to the column signal line 22 .
  • the control unit 6 changes the drive signal ⁇ S to Hi and turns on the first holding switch transistor 15 , whereby the floating diffusion region 12 and the first holding capacitor 13 are electrically connected. Thereby, the thermal noise charges in the floating diffusion region 12 and the first holding capacitor 13 and the dark current charges generated due to the dark current generated during the accumulation of signal charges in the photoelectric conversion element 11 are mixed, and the floating charge at this time is mixed.
  • the voltage of the diffusion region 12 (holding capacitance reference potential) is read out from the source follower circuit SF after a finite time from the time t03 when it appears in the source follower circuit SF, and after A/D conversion, as the first signal (pixel signal) is stored in memory 8A.
  • the column signal processing unit 4 performs the A/D conversion in the state (that is, the state of conversion into a digital signal).
  • a signal is stored in the memory 8A, but it is not limited to this structure.
  • Each subsequent process may be performed while the pixel signal (voltage of the floating diffusion region 12 ) read out from the source follower circuit SF is maintained as an analog signal.
  • the control unit 6 changes the drive signal ⁇ S to Low, turns off the first holding switch transistor 15, and electrically disconnects the floating diffusion region 12 from the first holding capacitor 13.
  • the potential of the floating diffusion area 12 (floating diffusion area reference potential) is read out from the source follower circuit SF, and is stored in the memory 8A as a second signal (pixel signal) after A/D conversion.
  • the second signal also includes a dark current component stored in the first holding switch transistor 15 .
  • the control unit 6 changes the drive signal ⁇ TX to Hi, turns on the transfer transistor 14, transfers the signal charge accumulated by the photoelectric conversion element 11 during the accumulation period ⁇ T to the floating diffusion region 12, and then switches the drive signal ⁇ TX becomes Low, turning off the transfer transistor 14.
  • This signal is read out from the source follower circuit SF at time t06 and is stored in the memory 8A as a third signal (pixel signal) after A/D conversion.
  • the control unit 6 changes the drive signal ⁇ S to Hi, turns on the first holding switching transistor 15, thereby turning on the floating diffusion region 12 and the first holding capacitor 13, and then changes the driving signal ⁇ TX to Hi again. Hi and Low turn the transfer transistor 14 on and off.
  • the voltage of the floating diffusion region 12 at this time is read out from the source follower circuit SF, and is stored in the memory 8A as a fourth signal (pixel signal) after A/D conversion.
  • the control unit 6 changes the drive signal ⁇ S1 to Hi and turns on the second holding switching transistor 15A. Thereby, the floating diffusion region 12 and the first holding capacitor 13 and the second holding capacitor 13A are turned on. Then, from this state, the control unit 6 changes the drive signal ⁇ TX to Hi and Low again, thereby turning the transfer transistor 14 on and off.
  • the voltage of the floating diffusion region 12 at this time is read out from the source follower circuit SF, and is stored in the memory 8A as the fifteenth signal (pixel signal) after A/D conversion.
  • the signal charge is included in the fifteenth signal.
  • the control unit 6 changes the drive signal ⁇ RES to Hi, turns on the reset transistor 16, and connects the floating diffusion region 12, the first holding capacitor 13, and the second holding capacitor 13A to the reset power supply (reset potential) VDD1 , all the signal charges in the floating diffusion region 12, the first holding capacitor 13 and the second holding capacitor 13A are initialized.
  • the voltage (reset level) of the initialized floating diffusion area 12, the first holding capacitor 13 and the second holding capacitor 13A is read out from the source follower circuit SF, and is used as the sixteenth signal (pixel signal) after A/D conversion. ) is stored in the memory 8A.
  • the control unit 6 changes the drive signal ⁇ S1 to Low and turns off the second holding switch transistor 15A, so that the floating diffusion region 12 and the second holding capacitor 13A are separated from each other.
  • the voltage (reset level) of a holding capacitor 13 is read out from the source follower circuit SF, and is stored in the memory 8A as the seventeenth signal (pixel signal) after A/D conversion.
  • the signal processing unit 7 performs signal processing based on the above-mentioned premises (first to fourth premises). Details are as follows.
  • each pixel signal (the first to fourth signals and the fifteenth to seventeenth signals) is read out from a certain pixel 10, the pixel signal is stored in the memory 8A, and the conversion result of each pixel 10 is processed in the signal processing Part 7 performs one-by-one processing, parallel processing, pipeline processing, etc.
  • the memory 8A of this embodiment has: a first signal storage unit 801 that stores a first signal; a second signal storage unit 802 that stores a second signal; and a third signal storage unit 803. It stores the third signal; the fourth signal storage part 804, which stores the fourth signal; the fifteenth signal storage part 815, which stores the fifteenth signal; the sixteenth signal storage part 816, which stores the sixteenth signal;
  • the seventeenth signal storage unit 817 stores the seventeenth signal;
  • the first offset storage unit 821 stores the first offset value (arbitrary) taking into account the dark current of the first holding capacitor 13; the second offset amount
  • the storage unit 822 similarly stores the second offset value taking into account the dark current of the second holding capacitor 13A;
  • the first gain storage unit 831 stores the first gain coefficient for adjusting the charge-to-voltage conversion gain; the second gain
  • the storage part 832 stores the second gain coefficient for adjusting the charge-to-voltage conversion gain; and the third gain storage part 833 stores the third gain coefficient for adjusting the charge-to-voltage
  • the memory 8A has a third threshold storage unit 843 that stores a first threshold storage unit 841, a second threshold storage unit 842, and a third threshold value.
  • the third threshold is set based on at least the capacitance of the floating diffusion region 12 , the first holding capacitor 13 and the second holding capacitor 13A.
  • the third threshold is, for example, a signal amount at which the second holding capacitor 13A is saturated.
  • the arithmetic unit 71A of the signal processing unit 7 converts the tenth signal of the memory 8A.
  • the signal (fourth differential signal) ⁇ is calculated by multiplying the third gain coefficient stored in the third gain storage unit 833 (fourth signal processing), based on the third signal stored in the third signal storage unit 803 of the memory 8A and
  • the difference calculation signal (second difference signal) Z of the second signal stored in the second signal storage unit 802 (first signal processing) is used to make the fourth signal stored in the fourth signal storage unit 804 of the memory 8A and the first signal
  • the difference of the first signal stored in the storage unit 801 is multiplied by the second gain coefficient stored in the second gain storage unit 832 to calculate the signal (
  • the signal (third differential signal) X is calculated using the first gain coefficient (third signal processing) stored in the first gain storage unit 831 .
  • the signal ⁇ , the signal X, the signal Y, and the signal Z calculated by the arithmetic unit 71A are input to the selector 73 before final output and wait for an output instruction.
  • the calculation unit 71A calculates the signal ⁇ , the signal threshold, it is instructed to output the signal ⁇ to the selector 73.
  • the judgment unit 72A In comparing the signal ⁇ with the third threshold, when the signal ⁇ is equal to or less than the third threshold, the judgment unit 72A next compares the signal X with the first threshold stored in the first threshold storage unit 841. When the signal When it is greater than the first threshold, it is instructed to output the signal X to the selector 73 .
  • the signal Y is instructed to be output to the selector 73 .
  • the determination unit 72A instructs the signal Z to be output to the selector 73 .
  • the selector 73 When the above-described arbitrary instruction (output instruction instruction) is input to the selector 73 through the judgment unit 72A, the selector 73 outputs any one of the signal ⁇ , the signal X, the signal Y, and the signal Z (processing result) based on the input instruction.
  • the judgment is performed in the order of preventing false judgments of the signal Z and the signal Y.
  • the solid-state imaging device 1A of this embodiment is provided with: a second storage capacitor 13A, which, unlike the first storage capacitor 13, can accumulate signal charges overflowing from the photoelectric conversion element 11; and a transfer transistor (first switching transistor) 14, which is connected to the photoelectric conversion element 11.
  • the conversion element 11 and the above-mentioned floating diffusion area 12 the first holding switching transistor (second switching transistor) 15, which connects the floating diffusion area 12 and the holding capacitor 13; the reset transistor (third switching transistor) 16, which connects the second holding capacitor 13A and reset power supply (reset potential) VDD1; and a second holding switching transistor (fourth switching transistor) 15A, which connects the first holding capacitor 13 and the second holding capacitor 13A.
  • the floating diffusion region 12 is connected to the second holding capacitor 13A via the first holding switching transistor 15 and the second holding switching transistor 15A in sequence. Furthermore, the floating diffusion region 12 is connected to the reset power supply VDD1 via the first holding switching transistor 15 , the second holding switching transistor 15A, and the reset transistor 16 in sequence. In addition, the first holding capacitor 13 is connected to the reset power supply VDD1 via the second holding switching transistor 15A and the reset transistor 16 in sequence.
  • the signal processing unit 7 of the solid-state imaging device 1A converts the slave transfer transistor 14, the hold switch transistor 15, the second hold switch transistor 15A, and the reset transistor 16 into The signal of the voltage of the floating diffusion region 12 when the first holding switching transistor 15 is turned on by the control part 6 is used as the first signal.
  • the first holding switching transistor 15 will be controlled based on the first signal.
  • the signal of the voltage of the floating diffusion region 12 when the part 6 is turned off is used as the second signal.
  • the signal based on the voltage of the floating diffusion region 12 when the transfer transistor 14 is turned on and off by the control part 6 is used.
  • the third signal As the third signal, after the third signal is obtained, a signal based on the voltage of the floating diffusion region 12 when the transfer transistor 14 is turned on and off in a state where the switching transistor 15 is kept turned on by the control part 6 is used as the fourth signal.
  • the signal based on the voltage of the floating diffusion region 12 when the transfer transistor 14 is turned on and off in a state where the holding switching transistor 15 and the second holding switching transistor 15A are turned on by the control unit 6 is used as The fifteenth signal, after the fifteenth signal is obtained, will be based on the floating diffusion when the reset transistor 16 is turned on and off when the first holding switch transistor 15 and the second holding switching transistor 15A are turned on by the control unit 6
  • the signal of the voltage of area 12 is used as the sixteenth signal.
  • the sixteenth signal is obtained, it is based on the floating diffusion when the second holding switching transistor 15A is turned off in the state where the first holding switching transistor 15 is turned on by the control part 6
  • the output signals (signal ⁇ , signal Signal Y, Signal Z).
  • the solid-state imaging device 1A of this embodiment configured as described above accumulates signal charges overflowing from the photoelectric conversion element 11 in the first storage capacitor 13 or the second storage capacitor 13A in a range where the amount of light input to the photoelectric conversion element 11 is large. Thereby achieving a high dynamic range while appropriately suppressing the SN ratio in the graph by outputting a signal generated by signal processing based on the amount of light input to the photoelectric conversion element 11 (the amount of signal charge generated by the photoelectric conversion element 11) Gaps G1, G2, and G3 at discontinuous positions (light amounts) (see FIG. 13), thereby suppressing errors caused by gaps G1, G2, and G3 in the final image of the camera or the like in which the solid-state imaging device 1A is installed. Image quality deteriorates.
  • the pixel 10A is provided with the second holding capacitor 13A in addition to the first holding capacitor 13, that is, it is provided with a plurality of holding capacitors. Therefore, compared with a pixel having only one holding capacitor, it is possible to accumulate the overflow from the photoelectric conversion element 11.
  • the capacitance of the signal charge is larger and, therefore, the dynamic range is larger.
  • the gap G3 in is a relatively large gap (see FIG. 13 ). However, since it is a gap at a position where the absolute value of the SN ratio is large, the gap G3 causes the final image in the camera or the like in which the solid-state imaging device 1A is arranged. The visual impact is weak.
  • the photoelectric conversion element 11 by obtaining seven signals (the first to fourth signals and the fifteenth to seventeenth signals) in the primary charge accumulation (primary light input) of the photoelectric conversion element 11, it is possible to adjust the intensity of the input light according to the The amount of light (the amount of signal charge generated by the photoelectric conversion element 11) should be corrected based on the signal processing by correlated double sampling and the voltage at the time of reset of the holding capacitor (the first holding capacitor 13 and the second holding capacitor 13A). any signal processing.
  • a plurality of storage capacitors (in the example of this embodiment, two storage capacitors, the first storage capacitor 13 and the second storage capacitor 13A) capable of accumulating signal charges overflowing from the photoelectric conversion element 11 are provided.
  • the amount of signal charges generated by the conversion element 11 and adjusting the number of storage capacitors used it is possible to suppress degradation in image quality due to thermal noise and other storage capacitors. That is, since the larger the storage capacitor is, the larger the thermal noise and the like that causes noise are.
  • the first storage capacitor 13 when the first storage capacitor 13 is used to accumulate signal charges generated by the photoelectric conversion element 11 without using the second storage capacitor, compared with the case where the second storage capacitor is used, By ensuring the same capacitance (the total capacitance of the first holding capacitor 13 and the second holding capacitor 13A) with one holding capacitor, it is possible to suppress degradation in image quality caused by the holding capacitance such as thermal noise.
  • correlated double sampling is included in the calculation (second signal processing) of obtaining the signal (first differential signal) Y based on the difference between the fourth signal and the first signal, and in obtaining In the operation (first signal processing) of a signal (second differential signal) Z based on the difference between the third signal and the second signal.
  • the correction of the voltage at the time of reset based on the holding capacitors includes the operation of obtaining the signal (third differential signal) X based on the difference between the fourth signal and the seventeenth signal. (third signal processing), and an operation (fourth signal processing) to obtain a signal (fourth differential signal) ⁇ based on the difference between the fifteenth signal and the sixteenth signal.
  • the solid-state imaging device 1A of the present embodiment includes a memory (storage unit) 8A that stores at least a first threshold set based on the capacitance of the photoelectric conversion element 11 and at least a capacitance set based on the floating diffusion region 12 . determined second threshold. Furthermore, the signal processing unit 7 compares the value of the signal (fourth differential signal) ⁇ with the third threshold.
  • the signal ⁇ When the value of the signal ⁇ is greater than the third threshold, the signal ⁇ is output as an output signal, and the value of the signal ⁇ is As a result of comparison with the third threshold, when the value of the signal ⁇ is below the third threshold, the value of the signal (third differential signal) X will be compared with the first threshold, and when the value of the signal X is greater than the first threshold , the signal X is output as an output signal. As a result of comparing the value of the signal X with the first threshold, when the value of the signal The two thresholds are compared. When the value of the signal Y is greater than the second threshold, the signal Y is output as an output signal. As a result of comparing the value of the signal Y with the second threshold, when the value of the signal Y is below the second threshold When , the signal (second differential signal) Z is output as the output signal.
  • the signal processing section 7 selects the signals ⁇ , ), that is, switching between signal processing by correlated double sampling and signal processing based on correction based on the voltage at the time of reset of the holding capacitor (first holding capacitor 13, second holding capacitor 13A), or the signal generated by these processes. Select Wait.
  • the first storage capacitor 13 is smaller than the second storage capacitor 13A.
  • the relative magnitude of noise (noise caused by the holding capacitance such as thermal noise) with respect to the signal corresponding to the number of charges read out from the holding capacitor is suppressed, that is, the above-mentioned The impact of noise on image quality is suppressed.
  • the second holding capacitor 13A used when the number of signal charges from the photoelectric conversion element 11 increases and the influence of the above-mentioned noise on the image quality is relatively small can achieve a high dynamic range and appropriately suppress the image quality caused by the holding capacitance. Decline.
  • the solid-state imaging device 1A of this embodiment is also similar to the solid-state imaging device 1 of the first embodiment. Instead of using the first storage capacitor 13 and the second storage capacitor 13A as Dual Conversion Gain, they are used as Dual Conversion Gain.
  • the storage capacitor is laterally overflowed, and the signal processing unit 7 performs predetermined signal processing at a new pixel driving time point (that is, a new driving time point for each transistor 14 to 16 in the pixel 10), thereby achieving higher photoelectric conversion.
  • the capacitance of element 11 has a large input dynamic range (high dynamic range), and at the same time can reduce the lateral overflow in the obtained pixel signal caused by the accumulated dark current in the storage capacitor (first holding capacitor 13 and second holding capacitor 13A) The impact of reset noise.
  • this effect can be enhanced by making the capacitance (saturation charge) of the photoelectric conversion element 11 larger than the capacitance of the floating diffusion region 12 .
  • the solid-state imaging device and the imaging device including the solid-state imaging device of the present invention are not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.
  • the configuration of a certain embodiment may be added to the configuration of another embodiment, or part of the configuration of a certain embodiment may be replaced with the configuration of another embodiment.
  • part of the configuration of a certain embodiment may be deleted.
  • the CMOS image sensor included in the solid-state imaging devices 1 and 1A of the first and second embodiments has at least a pixel array unit 2, a vertical drive unit 3, a plurality of column signal processing units 4, a horizontal drive unit 5, and a control unit 6. But it is not limited to this composition.
  • the CMOS image sensor (solid-state imaging element) may include a signal processing unit 7 or a memory 8 . That is, each signal (the first to fifth signals or the first to fourth and the fifteenth to seventeenth signals) calculated by the arithmetic processing unit may be stored (held) in a readout circuit in which the pixel signal is embedded, DSP and solid-state imaging devices in systems such as smartphones and cameras.
  • the specific structure of the signal processing (multiplication and accumulation of signals, determination of use of thresholds, etc.) in the signal processing unit 7 is not limited.
  • the signal processing unit 7 may perform weighted addition between signals before and after the threshold value to perform signal processing so that the difference in noise based on the readout difference is not noticeable in the slow gradation change unit, or may use a quadratic function.
  • Signal processing such as gain or lookup table rather than the gain of a simple linear function. That is, in the signal processing unit 7, it is appropriate to select what kind of threshold value judgment and multiplication and accumulation operations are performed, and the signal processing unit 7 may be configured to use the threshold value judgment and the multiplication and accumulation operation, etc. to convert the five signals (the first to the fifth signals) or Seven signals (the first to fourth signals, and the fifteenth to seventeenth signals) are made into one final signal.
  • the holding capacitors 13 and 13A used for correction of pixel signals are The reset level (voltage at reset: the fifth signal and the sixteenth signal in the examples of the first and second embodiments) is obtained immediately after the fourth signal or the fifteenth signal, that is, for the photoelectric conversion element 11 It is performed every time light is input, but it is not limited to this structure.
  • the reset level of the holding capacitor may be obtained in an initial stage, and the obtained reset level may be used as a known value each time light is input to the photoelectric conversion element 11 .
  • reset power supply reset potential
  • VDD2 power supply
  • X third differential signal
  • Y first differential signal
  • Z second differential signal
  • ⁇ fourth differential signal
  • ⁇ RES sixth differential signal
  • ⁇ S seventh differential signal

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Abstract

提供一种固体拍摄装置，具备：光电转换元件，其根据输入的光，通过光电转换产生电荷；浮动扩散区，其将电荷转换为与该电荷的量相应的电压；保持电容，其连接浮动扩散区，并且能够积累从光电转换元件溢出的电荷；以及信号处理部，其处理基于由浮动扩散区转换的电压的信号，信号处理部具有信号的多个处理单元，信号是使用保持电容读出的。

Description

固体拍摄装置、以及具备固体拍摄装置的拍摄装置 技术领域
本发明涉及固体拍摄装置、以及具备固体拍摄装置的拍摄装置。
背景技术
以往，已知实现高动态范围的固体拍摄元件(参照US2017/0099423号公报)。
该固体拍摄元件是具备所谓的横向溢出集合电容(Lateral Over flow Integration Capacitor：LOFIC)的CMOS图像传感器等，如图14以及图15所示，该固体拍摄元件500的各像素501具备：光电二极管(光电转换元件)502；将由光电二极管502产生的电荷转换为与该电荷的量相应的电压的浮动扩散区503；以及能够积累从光电二极管502溢出的电荷的横向溢出存储电容504。此外，图14以及图15的电势图中的各区域的附图标记是图14的等效电路图的对应的构成的附图标记的后面加P。另外，图15的附图标记t1～t9对应于图16所示的各晶体管的驱动时间点t1～t9的附图标记。
在该固体拍摄元件500的各像素501中，当向光电二极管502的入射光的光量大时，从该光电二极管502溢出的电荷积累到横向溢出存储电容504(参照由图15中的附图标记504P所示的区域)，通过将该横向溢出存储电容504中积累的电荷读出，从而实现高动态范围(即，光电二极管502的电容以上的输入动态范围)。
具体地说，在各像素501中，当向光电二极管502的入射光的光量大时，即在光电二极管502中产生的电荷超过其电容而溢出时，在浮动扩散区503的转换增益高的状态(即，配置在浮动扩散区503与横向溢出存储电容504之间的开关晶体管505为关断的状态)下，读出来自光电二极管502的电荷(参照图16的t4～t7)，接着，降低浮动扩散区503的转换增益(即，配置在浮动扩散区503与横向溢出存储电容504之间的开关晶体管505导通的状态下)，读出光电二极管502和横向溢出存储电容504的总计电荷(参照图16的t8～t11)，由此，实现光电二极管502的电容以上的输入动态范围。
然而，在上述固体拍摄元件500中，在光电二极管502中，在积累由入射光产生的电荷期间会产生暗电流，或者在横向溢出存储电容504中，为了了解复位电平(复位信号)而进行复位读出，从而产生热噪声，但由于无法进行相关双采样，因此SN比劣化。
详细地，在各像素501中，输入的光量大的光时，从光电二极管502溢出的电荷中的、无法由浮动扩散区503保持的电荷积累在横向溢出存储电容504中，在读出该横向溢出存储电容504中积累的电荷后，通过像素的复位信号读出横向溢出存储电容504。
因此，虽然可以通过像素501读取超过光电二极管502的电容的信号量(光量大的光)，但由于在电荷开始从光电二极管502溢出的光量的前后，横向溢出存储电容504的复位电平所具有的热噪声、以及叠加在从光电二极管502溢出的电荷(信号)的暗电流及其散粒噪音的影响，会产生图17所示那样大的SN比的不连续性(间隙)G。
这种SN比的不连续性在色调逐渐变化的被摄体，例如，在天空、皮肤、云等中特别明显，且会是使固体拍摄元件500的画质下降的主要原因。
现有技术文献
专利文献
专利文献1：US2017/0099423号公报。
发明内容
发明要解决的问题
因此，本发明的目的在于，提供一种固体拍摄装置、以及具备固体拍摄装置的拍摄装置，能够实现高动态范围，并且能够抑制SN比的间隙导致的画质下降。
用于解决问题的方案
本发明的固体拍摄装置具备：
光电转换元件，其根据输入的光，通过光电转换产生电荷；
浮动扩散区，其将上述电荷转换为与该电荷的量相应的电压；
保持电容，其连接到上述浮动扩散区，并且能够积累从上述光电转换元件溢出的上述电荷；以及
信号处理部，其处理基于在上述浮动扩散区转换的上述电压的信号，
上述信号处理部具有信号的多个处理单元，所述信号是使用上述保持电容读出的。
也可以是，在上述固体拍摄装置中，
上述多个处理单元可以包含相关双采样单元、以及基于上述保持电容的复位时的电压对信号进行校 正的校正单元。
另外，本发明的固体拍摄装置具备：
光电转换元件，其根据输入的光，通过光电转换产生电荷；
浮动扩散区，其将上述电荷转换为与该电荷的量相应的电压；
保持电容，其连接到上述浮动扩散区，并且能够积累从上述光电转换元件溢出的上述电荷；以及
信号处理部，其处理基于在上述浮动扩散区转换的上述电压的信号，
上述信号处理部，
当处于上述光输入到上述光电转换元件而生成的上述电荷没有从该光电转换元件溢出的第一状态时，对在上述浮动扩散区中的转换增益不同的上述信号分别进行相关双采样，
当处于上述光输入到上述光电转换元件而生成的上述电荷从该光电转换元件溢出的第二状态时，基于上述保持电容的复位时的电压对上述信号进行校正。
另外，也可以是，上述固体拍摄装置具备：
第一开关晶体管，其连接上述光电转换元件与上述浮动扩散区；
第二开关晶体管，其连接上述浮动扩散区与上述保持电容；
第三开关晶体管，其连接上述保持电容与复位电位；以及
控制部，其控制各开关晶体管，
上述浮动扩散区依次经由上述第二开关晶体管和上述第三开关晶体管与上述复位电位连接，
上述信号处理部，
在上述光输入到上述光电转换元件后，将基于从上述第一～第三开关晶体管关断的状态开始在上述第二开关晶体管被上述控制部导通时的上述浮动扩散区的电压的信号作为第一信号，
在得到上述第一信号后，将基于上述第二开关晶体管被上述控制部关断时的上述浮动扩散区的电压的信号作为第二信号，
在得到上述第二信号后，将基于上述第一开关晶体管被上述控制部导通以及关断时的上述浮动扩散区的电压的信号作为第三信号，
在得到上述第三信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第四信号，
在得到上述第四信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第三开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第五信号时，
可以基于上述第一～第五信号生成从该固体拍摄装置输出到外部的输出信号。
另外，也可以是，在上述固体拍摄装置中，
上述相关双采样分别包含于基于上述第四信号和上述第一信号的差分获得第一差分信号的信号处理、以及基于上述第三信号和上述第二信号的差分获得第二差分信号的信号处理中，
基于上述保持电容的复位时的电压的校正包含于基于上述第四信号和上述第五信号的差分获得第三差分信号的信号处理中。
另外，也可以是，上述固体拍摄装置具备：
存储部，其存储至少基于上述光电转换元件的电容设定的第一阈值、以及至少基于上述浮动扩散区的电容设定的第二阈值，
上述信号处理部，
将上述第三差分信号的值与上述第一阈值进行比较，当上述第三差分信号的值大于上述第一阈值时，将该第三差分信号作为上述输出信号输出，
作为将上述第三差分信号的值与上述第一阈值进行比较的结果，当上述第三差分信号的值为上述第一阈值以下时，将上述第一差分信号的值与上述第二阈值进行比较，当上述第一差分信号的值大于上述第二阈值时，将该第一差分信号作为上述输出信号输出，
作为将上述第一差分信号的值与上述第二阈值进行比较的结果，当上述第一差分信号的值为上述第二阈值以下时，将上述第二差分信号作为上述输出信号输出。
另外，也可以是，在上述固体拍摄装置中，具备：
第二保持电容，其与作为上述保持电容的第一保持电容不同，能够积累从上述光电转换元件溢出的上述电荷；
第一开关晶体管，其连接上述光电转换元件与上述浮动扩散区；
第二开关晶体管，其连接上述浮动扩散区与上述保持电容；
第三开关晶体管，其连接上述第二保持电容与复位电位；
第四开关晶体管，其连接上述第一保持电容与上述第二保持电容；以及
控制部，其控制各开关晶体管，
上述浮动扩散区依次经由上述第二开关晶体管和上述第四开关晶体管与上述第二保持电容连接，并且依次经由上述第二开关晶体管、上述第四开关晶体管、以及上述第三开关晶体管与上述复位电位连接，
上述第一保持电容依次经由上述第四开关晶体管和上述第三开关晶体管与上述复位电位连接，
上述信号处理部，
在上述光输入到上述光电转换元件后，将基于从上述第一～第四开关晶体管关断的状态开始在上述第二开关晶体管被上述控制部导通时的上述浮动扩散区的电压的信号作为第一信号，
在得到上述第一信号后，将基于上述第二开关晶体管被上述控制部关断时的上述浮动扩散区的电压的信号作为第二信号，
在得到上述第二信号后，将基于上述第一开关晶体管被上述控制部导通以及关断时的上述浮动扩散区的电压的信号作为第三信号，
在得到上述第三信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第四信号，
在得到上述第四信号后，将基于在上述第二开关晶体管以及上述第四开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第十五信号，
在得到上述第十五信号后，将基于在上述第二开关晶体管以及上述第四开关晶体管被上述控制部导通的状态下上述第三开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第十六信号，
在得到上述第十六信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第四开关晶体管关断时的上述浮动扩散区的电压的信号作为第十七信号时，
基于上述第一～第四信号以及第十五～第十七信号生成从该固体拍摄装置输出到外部的输出信号。
另外，也可以是，在上述固体拍摄装置中，
上述相关双采样分别包含于基于上述第四信号和上述第一信号的差分获得第一差分信号的信号处理、以及基于上述第三信号和上述第二信号的差分获得第二差分信号的信号处理中，
基于上述保持电容的复位时的电压的校正分别包含于基于上述第四信号和上述第十七信号的差分获得第三差分信号的信号处理、以及基于上述第十五信号和上述第十六信号的差分获得第四差分信号的信号处理中。
另外，也可以是，上述固体拍摄装置，
具备存储部，其存储至少基于上述光电转换元件的电容设定的第一阈值，至少基于上述浮动扩散区的电容设定的第二阈值、以及至少基于上述浮动扩散区的电容以及上述第一保持电容设定的第三阈值，
上述信号处理部，
将上述第四差分信号的值与上述第三阈值进行比较，当上述第四差分信号的值大于上述第三阈值时，将该第四差分信号作为上述输出信号输出，
作为将上述第四差分信号的值与上述第三阈值进行比较的结果，当上述第四差分信号的值为上述第三阈值以下时，将上述第三差分信号的值与上述第一阈值进行比较，当上述第三差分信号的值大于上述第一阈值时，将该第三差分信号作为上述输出信号输出，
作为将上述第三差分信号的值与上述第一阈值进行比较的结果，当上述第三差分信号的值为上述第一阈值以下时，将上述第一差分信号的值与上述第二阈值进行比较，当上述第一差分信号的值大于上述第二阈值时，将该第一差分信号作为上述输出信号输出，
作为将上述第一差分信号的值与上述第二阈值进行比较的结果，当上述第一差分信号的值为上述第二阈值以下时，将上述第二差分信号作为上述输出信号输出。
另外，也可以是，在上述固体拍摄装置中，
上述第一保持电容小于上述第二保持电容。
另外，本申请所涉及的拍摄装置具备上述任一的固体拍摄装置。
附图说明
图1是示出第一实施方式的固体拍摄装置的构成的图。
图2是上述固体拍摄装置所具备的像素的等效电路图。
图3是示出上述像素的驱动时间点、以及与该驱动时间点对应的像素信号的图。
图4是示出上述像素的驱动时间点、以及与该驱动时间点对应的像素信号的图。
图5是示出上述像素的驱动时间点、以及与该驱动时间点对应的像素信号的图。
图6是上述固体拍摄装置所具备的信号处理部的数据流程图。
图7是表示上述像素的输入输出特性的图表。
图8是示出上述像素的SN比的图表。
图9是示出第二实施方式的固体拍摄装置的构成的图。
图10是上述固体拍摄装置所具备的像素的等效电路图。
图11是上述像素的时序图。
图12是上述固体拍摄装置所具备的信号处理部的数据流程图。
图13是示出上述像素的SN比的图表。
图14是现有的固体拍摄装置所具备的像素的等效电路图、以及电势图。
图15是示出上述像素中的信号电荷的流动的电势图。
图16是示出上述像素的驱动时间点的图。
图17是示出上述像素的SN比的图表。
具体实施方式
本实施方式的固体拍摄装置具备：
光电转换元件，其根据输入的光，通过光电转换产生电荷；
浮动扩散区，其将上述电荷转换为与该电荷的量相应的电压；
保持电容，其连接到上述浮动扩散区，并且能够积累从上述光电转换元件溢出的上述电荷；以及
信号处理部，其处理基于在上述浮动扩散区转换的上述电压的信号，
上述信号处理部具有信号的多个处理单元，所述信号是使用上述保持电容读出的。
根据该构成，在输入的光的光量大的范围内，保持电容积累溢出的电荷，从而实现高动态范围，同时通过输出由根据输入到光电转换元件的光的光量(由光电转换元件产生的电荷的量)的信号处理生成的信号，适当地抑制SN比的图表中的不连续的位置(光量)的间隙，由此，抑制了由于该间隙导致的画质下降。详细内容如下。
即使光电转换元件由于光的输入而产生的电荷超过该光电转换元件的电容而溢出，保持电容也会积累该溢出的电荷，并在从浮动扩散区读出由光电转换元件产生的电荷时读出该保持电容中积累的电荷，从而实现光电转换元件的电容以上的输入动态范围(即，高动态范围)。
另外，针对在使用保持电容读出由光电转换元件产生的电荷时的信号，通过多个处理单元进行适当的信号处理，从而可以适当地抑制SN比的图表中的不连续的位置(光量)的间隙。
在这种情况下，例如，
可以是，上述多个处理单元可以包含相关双采样单元、以及基于上述保持电容的复位时的电压对信号进行校正的校正单元。
这样，对使用保持电容读出由光电转换元件产生的电荷的信号进行相关双采样，从而，该信号不受光电转换元件中的电荷的积累过程中产生的暗电流或保持电容产生的热噪声的影响或该影响被充分抑制。另外，当输入的光的光量大并且从光电转换元件溢出电荷时，虽然能使用积累有该溢出的电荷的保持电容对读出的由光电转换元件产生的电荷的信号进行基于保持电容的复位时的电压的校正，但该被校正的信号受到由光电转换元件产生的暗电流或保持电容产生的热噪声等的影响。然而，对于上述溢出的光量，由于所读出的信号(电荷数)大，因此在该信号中暗电流或热噪声的影响相对变小，由此，抑制了SN比的图表中的不连续位置(上述开始溢出的位置)的间隙(例如，参照图8所示的间隙G1、G2)。
另外，本实施方式的固体拍摄装置具备：
光电转换元件，其根据输入的光，通过光电转换产生电荷；
浮动扩散区，其将上述电荷转换为与该电荷的量相应的电压；
保持电容，其连接到上述浮动扩散区，并且能够积累从上述光电转换元件溢出的上述电荷；以及
信号处理部，其处理基于在上述浮动扩散区转换的上述电压的信号，
上述信号处理部，
当处于上述光输入到上述光电转换元件而生成的上述电荷没有从该光电转换元件溢出的第一状态时，对在上述浮动扩散区中的转换增益不同的上述信号分别进行相关双采样，
当处于上述光输入到上述光电转换元件而生成的上述电荷从该光电转换元件溢出的第二状态时，基于上述保持电容的复位时的电压对上述信号进行校正。
根据该构成，通过在输入的光的光量大的范围(即，向光电转换元件输入上述光而生成的上述电荷从该光电转换元件溢出的第二状态)内，保持电容积累溢出的电荷，从而实现高动态范围，同时通过输出由根据输入到光电转换元件的光的光量(光电转换元件产生的电荷的量)的信号处理生成的信号，适当地抑制SN比的图表中的不连续的位置(光量)的间隙，由此，抑制了由于该间隙导致的画质下降。详细内容如下。
即使光电转换元件由于光的输入而产生的电荷超过该光电转换元件的电容而溢出，保持电容也会积累该溢出的电荷，并在从浮动扩散区读出由光电转换元件产生的电荷(信号)时读出该保持电容中积累的电荷，从而实现光电转换元件的电容以上的输入动态范围(即，高动态范围)。
另外，在第一状态下，对于由光电转换元件产生的电荷的从浮动扩散区的以不同的转换增益的读出(例如，高转换增益下的读出和低转换增益下的读出)均可以进行相关双采样，因此，这些读出的信号不受光电转换元件中的电荷的积累过程中产生的暗电流或保持电容产生的热噪声的影响或该影响被充分抑制，因此，抑制了SN比的图表中的不连续位置(转换增益切换的位置)的间隙(例如，参照图8的间隙G1)。
另一方面，虽然能基于保持电容的复位时的电压校正电荷从光电转换元件溢出的状态(第二状态)下的读出信号，但由于无法进行相关双采样，因此该读出信号会受到由光电转换元件产生的暗电流或保持电容产生的热噪声等的影响。但是，对于上述溢出的光量，由于被读出的信号(电荷数)大，因此在该信号中暗电流或热噪声的影响相对变小，由此，抑制了SN比的图表中的不连续位置(上述开始溢出的位置)的间隙(例如，参照图8的间隙G2)。
如上所述，根据上述构成，由于在SN比的图表中不连续位置的间隙分别得到抑制(变小)，因此，有效地抑制了由于该间隙导致的画质下降。
另外，可以是，上述固体拍摄装置具备：
第一开关晶体管，其连接上述光电转换元件与上述浮动扩散区；
第二开关晶体管，其连接上述浮动扩散区与上述保持电容；
第三开关晶体管，其连接上述保持电容与复位电位；以及
控制部，其控制各开关晶体管，
上述浮动扩散区依次经由上述第二开关晶体管和上述第三开关晶体管与上述复位电位连接，
上述信号处理部，
在上述光输入到上述光电转换元件后，将基于从上述第一～第三开关晶体管关断的状态开始在上述第二开关晶体管被上述控制部导通时的上述浮动扩散区的电压的信号作为第一信号，
在得到上述第一信号后，将基于上述第二开关晶体管被上述控制部关断时的上述浮动扩散区的电压的信号作为第二信号，
在得到上述第二信号后，将基于上述第一开关晶体管被上述控制部导通以及关断时的上述浮动扩散区的电压的信号作为第三信号，
在得到上述第三信号后，将基于上述第二开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第四信号，
在得到上述第四信号后，将基于上述第二开关晶体管被上述控制部导通的状态下上述第三开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第五信号时，
可以基于上述第一～第五信号生成从该固体拍摄装置输出到外部的输出信号。
这样，通过在光电转换元件的一次电荷积累(输入一次光)中获得五个信号(第一～第五信号)，可以根据输入的光的光量(由光电转换元件产生的电荷的量)应对通过相关双采样的信号处理、以及基于保持电容的复位时的电压进行校正的信号处理中的任意一个信号处理。
在这种情况下，例如，在上述固体拍摄装置中，
上述相关双采样分别包含于基于上述第四信号和上述第一信号的差分获得第一差分信号的信号处理、以及基于上述第三信号和上述第二信号的差分获得第二差分信号的信号处理中，
基于上述保持电容的复位时的电压的校正包含于基于上述第四信号和上述第五信号的差分获得第三差分信号的信号处理中。
另外，也可以是，上述固体拍摄装置具备：
存储部，其存储至少基于上述光电转换元件的电容设定的第一阈值、以及至少基于上述浮动扩散区的电容设定的第二阈值，
上述信号处理部，
将上述第三差分信号的值与上述第一阈值进行比较，当上述第三差分信号的值大于上述第一阈值时，将该第三差分信号作为上述输出信号输出，
作为将上述第三差分信号的值与上述第一阈值进行比较的结果，当上述第三差分信号的值为上述第一阈值以下时，将上述第一差分信号的值与上述第二阈值进行比较，当上述第一差分信号的值大于上述第二阈值时，将该第一差分信号作为上述输出信号输出，
作为将上述第一差分信号的值与上述第二阈值进行比较的结果，当上述第一差分信号的值为上述第二阈值以下时，将上述第二差分信号作为上述输出信号输出。
这样，信号处理部使用两个阈值选择要输出的信号，从而更可靠地进行根据输入到光电转换元件的光的光量(由光电转换元件产生的电荷的量)的信号处理，即通过相关双采样的信号处理与基于保持电容的复位时的电压进行校正的信号处理的切换或通过这些处理生成的信号的选择等。
另外，也可以是，上述固体拍摄装置具备：
第二保持电容，其与作为上述保持电容的第一保持电容不同，能够积累从上述光电转换元件溢出的上述电荷；
第一开关晶体管，其连接上述光电转换元件与上述浮动扩散区；
第二开关晶体管，其连接上述浮动扩散区与上述保持电容；
第三开关晶体管，其连接上述第二保持电容与复位电位；
第四开关晶体管，其连接上述第一保持电容与上述第二保持电容；以及
控制部，其控制各开关晶体管，
上述浮动扩散区依次经由上述第二开关晶体管和上述第四开关晶体管与上述第二保持电容连接，并且依次经由上述第二开关晶体管、上述第四开关晶体管、以及上述第三开关晶体管与上述复位电位连接，
上述第一保持电容依次经由上述第四开关晶体管和上述第三开关晶体管与上述复位电位连接，
上述信号处理部，
在上述光输入到上述光电转换元件后，将基于从上述第一～第四开关晶体管关断的状态开始在上述第二开关晶体管被上述控制部导通时的上述浮动扩散区的电压的信号作为第一信号，
在得到上述第一信号后，将基于上述第二开关晶体管被上述控制部关断时的上述浮动扩散区的电压的信号作为第二信号，
在得到上述第二信号后，将上述第一开关晶体管被上述控制部导通以及关断时的基于上述浮动扩散区的电压的信号作为第三信号，
在得到上述第三信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第四信号，
在得到上述第四信号后，将基于在上述第二开关晶体管以及上述第四开关晶体管被上述控制部导通的状态下上述第一开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第十五信号，
在得到上述第十五信号后，将基于在上述第二开关晶体管以及上述第四开关晶体管被上述控制部导通的状态下上述第三开关晶体管导通以及关断时的上述浮动扩散区的电压的信号作为第十六信号，
在得到上述第十六信号后，将基于在上述第二开关晶体管被上述控制部导通的状态下上述第四开关晶体管关断时的上述浮动扩散区的电压的信号作为第十七信号时，
基于上述第一～第四信号以及第十五～第十七信号生成从该固体拍摄装置输出到外部的输出信号。
这样，通过在光电转换元件的一次电荷积累(输入一次光)中获得七个信号(第一～第四信号以及第十五～第十七信号)，可以根据输入的光的光量(由光电转换元件产生的电荷的量)应对通过相关双采样的信号处理、以及基于保持电容的复位时的电压进行校正的信号处理中的任意一个信号处理。
并且，具备能够积累从光电转换元件溢出的电荷的两个保持电容(第一保持电容和第二保持电容)，通过根据由光电转换元件产生的电荷的量来调整所使用的保持电容的数量，能够抑制由于热噪声等的保持电容导致的画质下降。即，由于保持电容越大，引起噪音的热噪声等越大，因此，在使用第一保持电容积累由光电转换元件产生的电荷而不使用第二保持电容的情况下，相比于通过一个保持电容确保相同电容(第一保持电容和第二保持电容的总计电容)的构成，可以抑制由热噪声等保持电容导致的画质下降。
在这种情况下，例如，在上述固体拍摄装置中，
上述相关双采样分别包含于基于上述第四信号和上述第一信号的差分获得第一差分信号的信号处理、以及基于上述第三信号和上述第二信号的差分获得第二差分信号的信号处理中，
基于上述保持电容的复位时的电压的校正分别包含于基于上述第四信号和上述第十七信号的差分获得第三差分信号的信号处理、以及基于上述第十五信号和上述第十六信号的差分获得第四差分信号的信号处理中。
另外，也可以是，上述固体拍摄装置具备存储部，
上述存储部存储至少基于上述光电转换元件的电容设定的第一阈值，至少基于上述浮动扩散区的电容设定的第二阈值、以及至少基于上述浮动扩散区的电容以及上述第一保持电容设定的第三阈值，
上述信号处理部，
将上述第四差分信号的值与上述第三阈值进行比较，当上述第四差分信号的值大于上述第三阈值时，将该第四差分信号作为上述输出信号输出，
作为将上述第四差分信号的值与上述第三阈值进行比较的结果，当上述第四差分信号的值为上述第 三阈值以下时，将上述第三差分信号的值与上述第一阈值进行比较，当上述第三差分信号的值大于上述第一阈值时，将该第三差分信号作为上述输出信号输出，
作为将上述第三差分信号的值与上述第一阈值进行比较的结果，当上述第三差分信号的值为上述第一阈值以下时，将上述第一差分信号的值与上述第二阈值进行比较，当上述第一差分信号的值大于上述第二阈值时，将该第一差分信号作为上述输出信号输出，
作为将上述第一差分信号的值与上述第二阈值进行比较的结果，当上述第一差分信号的值为上述第二阈值以下时，将上述第二差分信号作为上述输出信号输出。
这样，信号处理部使用三个阈值选择要输出的信号，从而更可靠地进行根据输入到光电转换元件的光的光量(由光电转换元件产生的电荷的量)的信号处理，即通过相关双采样的信号处理与基于保持电容的复位时的电压进行校正的信号处理的切换或通过这些处理生成的信号的选择等。
另外，在上述固体拍摄装置中，
上述第一保持电容优选小于上述第二保持电容。
随着保持电容中积累的电荷的数量增多，针对与从保持电容读出的上述电荷的数量相应的信号的噪音(由热噪声等保持电容引起的噪音)的相对大小被抑制，即，上述噪音对画质的影响被抑制。因此，通过减少在来自光电转换元件的电荷的数量小时使用的第一保持电容，以抑制在仅使用该第一保持电容时由该第一保持电容产生的噪音，并且增大在来自光电转换元件的电荷的数量变多且上述噪音对画质的影响相对变小时使用的第二保持电容，能够实现高动态范围，并能够适当地抑制由于保持电容引起的画质的下降。
另外，本申请所涉及的拍摄装置具备上述任一的固体拍摄装置。
以下，参照附图说明本发明的第一实施方式。
[拍摄装置的构成例]
本实施方式的拍摄装置例如是智能手机或数码摄像头。另外，本实施方式的固体拍摄装置是嵌入拍摄装置，并包含包含CMOS图像传感器等的固体拍摄元件(SOLID STATE IMAGE SENSOR)。此外，固体拍摄装置1至少包括固体拍摄元件，本实施方式的固体拍摄装置1包括CMOS图像传感器(固体拍摄元件)、信号处理部7、存储器8。
具体地说，如图1所示，嵌入该拍摄装置的固体拍摄装置1具备像素阵列部2、垂直驱动部3、多个列信号处理部4、水平驱动部5、控制部6以及信号处理部7。另外，固体拍摄装置1具备可以存储由信号处理部7处理的信号等的存储器8。在本实施方式的固体拍摄装置1中，至少由像素阵列部2、垂直驱动部3、多个列信号处理部4、水平驱动部5以及控制部6构成CMOS图像传感器。
至少，像素阵列部2、垂直驱动部3、列信号处理部4、水平驱动部5、控制部6以及信号处理部7配置在同一半导体基板上或电连接的多个半导体基板上。此外，信号处理部7以及存储器8可以配置于配置有像素阵列部2、垂直驱动部3、列信号处理部4、水平驱动部5以及控制部6的半导体基板，也可以配置在不同的基板上等。即，信号处理部7以及存储器8的配置位置不受限制。
像素阵列部2具有二维配置成矩阵状的多个像素10。这些多个像素10中的每一个都是有效单位像素，该有效单位像素具有光电转换元件11，光电转换元件11可以对输入的光(入射光)进行光电转换，在内部积累与输入的光量相应的量的信号电荷(电荷)，并输出该积累的信号电荷。后面叙述各像素10的具体构成的详细内容。
另外，除了有效单位像素之外，多个像素10还可以包括具有不具有光电转换元件的结构的伪单位像素或通过对受光面进行遮光来阻断来自外部的光的输入的遮光单位像素等。该遮光单位像素除了是对受光面进行遮光的结构以外，具备与有效单位像素相同的构成。
另外，像素阵列部2相对于矩阵状的像素排列，具有配置于各行且分别在行方向上延伸的多个行信号线21、以及配置于各列且分别在列方向上延伸的多个列信号线22。上述多个行信号线21中的每一个连接到垂直驱动部3，多个列信号线22中的每一个连接到对应的列信号处理部4。
垂直驱动部3例如由移位寄存器构成，选择规定的行信号线21，从而将用于驱动像素10的脉冲(信号)供应到所选择的行信号线21，以行为单位驱动像素10。详细地，垂直驱动部3以行为单位依次在垂直方向上选择扫描像素阵列部2的各像素10，通过列信号线22将基于在各像素10的光电转换元件11中根据输入的光量生成的信号电荷的像素信号供应到列信号处理部4。
多个列信号处理部4中的每一个配置于像素10的每一列，对从一行的像素10输出的像素信号按每个像素列进行降噪等信号处理。本实施方式的各列信号处理部4进行用于除去像素固有的固定模式噪音的相关双采样(Correlated Double Sampling：CDS)以及A/D(Analog/Digital)转换等信号处理。
水平驱动部5例如由移位寄存器构成，通过依次输出水平扫描脉冲，从而依次选择多个列信号处理部4中的每一个，依次将由各列信号处理部4进行信号处理后的像素信号输出到信号处理部7。
控制部6控制固体拍摄装置1的各部的动作。具体地说，控制部6接收输入时钟信号和用于指示动作模式等的数据，并且输出固体拍摄装置1的内部信息等数据。详细地，控制部6基于垂直同步信号、水平同步信号以及主时钟信号，生成作为垂直驱动部3、列信号处理部4以及水平驱动部5等的动作的基准的时钟信号或控制信号，并将所生成的时钟信号或控制信号输出到垂直驱动部3、列信号处理部4以及水平驱动部5等。
信号处理部7进行针对从各列信号处理部4输出的像素信号的运算处理等各种信号处理。具体地说，信号处理部7具有对像素信号进行运算的运算部71、对运算部的运算结果进行判断的判断部72、以及基于判断部的判断结果输出信号的选择器73(参照图6)。本实施方式的信号处理部7是DSP(Digital Signal Processor；数字信号处理器)。另外，后面叙述信号处理部7的具体处理内容。
此外，信号处理部7的具体的配置位置不受限制。虽然在本实施方式的固体拍摄装置1中信号处理部7配置在与CMOS图像传感器不同的位置，但也可以是信号处理部7的整个构成配置(搭载)于CMOS图像传感器，或者信号处理部7的一部分构成配置于CMOS图像传感器。
存储器8是行存储器、帧存储器、FIFO等，能够存储从各列信号处理部4输出的像素信号等。后面叙述该存储器8的具体构成。
[像素的构成]
接下来，参照图2说明按矩阵状配置于像素阵列部2的像素10的具体结构。
像素10具备：光电转换元件11，其根据输入的光，通过光电转换产生信号电荷；浮动扩散区12，其将由光电转换元件11产生的信号电荷转换为与该信号电荷的量相应的电压信号(电压)；以及保持电容13，其连接浮动扩散区12，并且能够积累从光电转换元件11溢出的信号电荷。本实施方式的光电转换元件11例如是光电二极管。
另外，像素10具备：传输晶体管(第一开关晶体管)14，其连接光电转换元件11与浮动扩散区12；保持开关晶体管(第二开关晶体管)15，其连接浮动扩散区12与保持电容13；复位晶体管(第三开关晶体管)16，其连接保持电容13与复位电源(复位电位)VDD1；放大晶体管17，其将浮动扩散区12的电压信号进行放大；以及选择晶体管18，其连接放大晶体管17与列信号线22。
针对以矩阵状配置的多个像素10，在每个像素行布线多个行信号线21。并且，各种驱动信号φTX、φS、φRES、φSEL从垂直驱动部3经行信号线21被供应到各像素10。上述驱动信号φTX、φS、φRES以及φSEL为上述脉冲。
浮动扩散区12将由光电转换元件11产生的信号电荷进行电荷电压转换为电压信号并将其输出。本实施方式的浮动扩散区12还依次经保持开关晶体管15和复位晶体管16与复位电源VDD1连接。
保持电容13为电容器，如上所述，经保持开关晶体管15与浮动扩散区12连接，并且还经复位晶体管16与复位电源VDD1连接。
对传输晶体管14的栅极电极施加驱动信号φTX。该驱动信号φTX基于来自控制部6的信号(指令)从垂直驱动部3输出。当驱动信号φTX变为Hi时(即，当传输晶体管14导通时)，传输晶体管14的传输栅极变为导通状态，光电转换元件11中积累的信号电荷经该传输晶体管14传输到浮动扩散区12。此外，当驱动信号φTX变为Low时，传输晶体管14关断。
对保持开关晶体管15的栅极电极施加驱动信号φS。该驱动信号φS基于来自控制部6的信号从垂直驱动部3输出。当驱动信号φS变为Hi(即，保持开关晶体管15导通)时，保持开关晶体管15的保持栅极变为导通状态，信号电荷可以从浮动扩散区12移动到保持电容13。此外，当驱动信号φS变为Low时，保持开关晶体管15关断。另外，即使保持开关晶体管15关断，也会调整保持开关晶体管15的保持栅极(势垒)，以在信号电荷从光电转换元件11溢出时积累到保持电容13中。
对复位晶体管16的栅极电极施加驱动信号φRES。该驱动信号φRES基于来自控制部6的信号从垂直驱动部3输出。当驱动信号φRES变为Hi(即，复位晶体管16导通)时，复位晶体管16的复位栅极变为导通状态，根据施加到保持开关晶体管15的栅极电极的驱动信号φS，浮动扩散区12以及保持电容13的电位或保持电容13的电位复位成复位电源(复位电位)VDD1的电平(复位电平)。此外，当驱动信号φRES变为Low时，复位晶体管16关断。
在放大晶体管17中，栅极电极连接浮动扩散区12，且漏极电极连接到电源VDD2。该放大晶体管17为将浮动扩散区12的电压作为像素信号读出的读出电路(所谓的源极跟随电路SF)的输入部。即，放大晶体管17通过使源极电极经选择晶体管18连接到列信号线22，从而构成连接到该列信号线22的一端的恒流源和源极跟随电路SF。
选择晶体管18连接到放大晶体管17的源极电极和列信号线22。对选择晶体管18的栅极电极施加驱动信号φSEL。该驱动信号φSEL基于来自控制部6的信号从垂直驱动部3输出。当驱动信号φSEL变为Hi(即，选择晶体管18导通)时，选择晶体管18的选择栅极变为导通状态，像素10变为选择状 态。由此，从放大晶体管17输出的像素信号经选择晶体管18输出到列信号线22。此外，当驱动信号φSEL变为Low时，选择晶体管18关断。
[固体拍摄装置的像素的驱动例]
另外参照图3～图5对如上述那样构成的像素10的驱动时间点进行说明。此外，图3～图5示出像素10的驱动信号(控制信号的脉冲)、以及相应地出现在列信号线22的输出电压(像素信号)，在上述图3～图5中，驱动信号φSEL、φRES、φS以及φTX都是相同的，各图中的Vout表示输出电压。
首先，在时刻t01，在选择晶体管18为关断的状态下，传输晶体管14、保持开关晶体管15、复位晶体管16导通，浮动扩散区12和保持电容13变为复位电平。
这样，在浮动扩散区12连接到复位电源VDD1的状态下传输晶体管14关断，由此光电转换元件11变为浮置状态，在光电转换元件11中开始积累通过光的输入产生的信号电荷。
几乎在传输晶体管14关断的同时(详细地，稍有延迟)，保持开关晶体管15、复位晶体管16分别关断，由此，浮动扩散区12和保持电容13也变为浮置状态。此时，在信号电荷从光电转换元件11溢出的(溢出来)情况下，浮动扩散区12和保持电容13可以保持(积累)该溢出来的信号电荷。
这样，在传输晶体管14、保持开关晶体管15以及复位晶体管16关断的状态下，在传输晶体管14关断后，从经过规定的积累期间ΔT之后的时刻t02开始读出该像素10的像素信号。
具体地说，当从像素10的各开关晶体管14～16、18为关断的状态开始，控制部6(详细地，接受控制部6的指令的垂直驱动部3)使驱动信号φSEL变为Hi从而将选择晶体管18导通时，该像素10与列信号线22连接。
之后，控制部6使驱动信号φS变为Hi，将保持开关晶体管15导通，由此浮动扩散区12与保持电容13电连接。由此，将浮动扩散区12和保持电容13中的热噪声(详细地，热噪声电荷)、以及光电转换元件11中的信号电荷的积累期间产生的暗电流(详细地，由暗电流产生的暗电流电荷)等混合，此时的浮动扩散区12的电压(保持电容基准电位)从出现于源极跟随电路SF的时刻t03起经过有限的时间从该源极跟随电路SF读出，在A/D转换之后，作为第一信号(像素信号)存储于存储器8。
在本实施方式的固体拍摄装置1中，在列信号处理部4，在A/D转换后的状态(即，转换为数字信号的状态)下，第一信号存储到存储器8中，但不限于该构成。也可以在从源极跟随电路SF读出的像素信号(浮动扩散区12的电压)保持为模拟信号的同时执行之后的各处理。此外，在之后的时间点，从源极跟随电路SF读出的像素信号(第二～第五信号)也是同样的。
接着，在时刻t04，控制部6使驱动信号φS变为Low，将保持开关晶体管15关断，使浮动扩散区12与保持电容13电断开。在该状态下，浮动扩散区12的电位(浮动扩散区基准电位)从源极跟随电路SF读出，在A/D转换之后，作为第二信号(像素信号)存储于存储器8。该第二信号还包含存储于保持开关晶体管15的暗电流成分。
接着，在时刻t05，控制部6使驱动信号φTX变为Hi，将传输晶体管14导通，在光电转换元件11将在积累期间ΔT期间积累的信号电荷传输到浮动扩散区12之后，使驱动信号φTX变为Low，将传输晶体管14关断。
该信号在时刻t06从源极跟随电路SF读出，在A/D转换之后，作为第三信号(像素信号)存储于存储器8。
接着，在时刻t07，控制部6在使驱动信号φS变为Hi并将保持开关晶体管15导通，由此使浮动扩散区12和保持电容13导通之后，再次使驱动信号φTX变为Hi以及Low，将传输晶体管14导通以及关断。此时的浮动扩散区12的电压从源极跟随电路SF读出，在A/D转换之后作为第四信号(像素信号)存储于存储器8。
最后，在时刻t08，控制部6使驱动信号φRES变为Hi，将复位晶体管16导通，由此将浮动扩散区12和保持电容13连接到复位电源(复位电位)VDD1，使浮动扩散区12和保持电容13的信号电荷全部初始化(复位)。在该初始化后的浮动扩散区12和保持电容13的电压(复位电平)从源极跟随电路SF读出，在A/D转换之后作为第五信号(像素信号)存储于存储器8。
在以上的像素10的驱动中，通过在积累期间ΔT输入到像素10(光电转换元件11)的光产生的信号电荷不超过光电转换元件11可以保持的电容，并且仅在浮动扩散区12处理光电转换元件11积累(保持)的信号电荷的情况下(第一前提的情况下：参照图3)，在时刻t05，低于浮动扩散区12的处理极限的信号电荷被传输到浮动扩散区12，从源极跟随电路SF读出的像素信号(浮动扩散区12的电压)相应地发生变化(参照Vout)。此时，像素信号(浮动扩散区12的电压：参照图3中的Vout)不超过A/D转换的范围(输入动态范围)。即，在浮动扩散区12中，信号被正确地保持而不会溢出。
另外，在时刻t07，由于再次导通和关断传输晶体管14没有从光电转换元件11传输到浮动扩散区12的新的信号电荷，因此，从源极跟随电路SF读出的第四信号(像素信号)成为与从光电转换元件 11传输的信号电荷以浮动扩散区12与保持电容13的电容比切分的状态下的浮动扩散区12的电压相应的信号。
在上述第一前提的情况下，还如图6所示，信号处理部7从第三信号中减去第二信号，从而由像素10光电转换后的最终信号(信号Z)被恢复。详细内容如下。
第二信号包括在光电转换元件11积累信号电荷的过程中(即，在积累期间ΔT期间)在浮动扩散区12和保持电容13中产生的暗电流、以及在时刻t01复位后产生的热噪声的全部，但通过信号电荷从光电转换元件11传输到浮动扩散区12从而生成第三信号以与该第二信号相加，可以进行相关双采样。由此，通过在信号处理部7从第三信号中减去第二信号等(参照图6的第一信号处理)，基于由电路的CMRR(共模抑制比)确定的性能，暗电流和热噪声在实际应用中几乎完全被除去，其结果是，由像素10光电转换后的最终信号(信号Z)被恢复。
此外，第一前提的情况下，存储于存储器8的其他信号(第一信号、第四信号以及第五信号)不需要最终信号(信号Z)的恢复。
另外，由在积累期间ΔT期间输入到像素10(光电转换元件11)的光产生的信号电荷由于不超过光电转换元件11可以保持的电容，因此不会从光电转换元件11溢出，但在超过浮动扩散区12可以处理的量并且是浮动扩散区12与保持电容13电连接的状态下可以处理的量的情况下(第二前提的情况下：参照图4)，由于在光电转换元件11中积累的信号电荷超过了浮动扩散区12可以处理的量，因此在时刻t06获得的第三信号是浮动扩散区12饱和的状态的信号。
但是，在时刻t06至时刻t07保持开关晶体管15导通且保持电容13电连接浮动扩散区12的状态下，再次进行从光电转换元件11向浮动扩散区12的信号电荷的传输，从而可以获得关于在积累期间ΔT期间由光电转换元件11产生的所有信号电荷的信号作为第四信号。
在上述第二前提的情况下，信号处理部7从第四信号中减去第一信号，从而恢复由像素10光电转换的最终信号(信号Y)。详细内容如下。
第一信号包含在光电转换元件11积累信号电荷的过程中在浮动扩散区12和保持电容13中产生的暗电流、以及在时刻t01复位后产生的热噪声等的全部，但通过所有信号电荷从光电转换元件11传输到在电连接保持电容13的状态下的浮动扩散区12从而生成第四信号以与该第一信号相加，可以进行相关双采样。由此，通过在信号处理部7从第四信号中减去第一信号(参照图6的第二信号处理)，基于由电路的CMRR确定的性能，暗电流和热噪声在实际应用中几乎完全被除去，其结果是，由像素10光电转换后的最终信号(信号Y)被恢复。
此外，第二前提的情况下，存储器8中存储的其他信号(第二信号、第三信号以及第五信号)不需要最终信号(信号Y)的恢复。
另外，由在积累期间ΔT期间输入到像素10(光电转换元件11)的光产生的信号电荷由于不超过光电转换元件11可以保持的电容，因此不会从光电转换元件11向保持电容13溢出，但当在浮动扩散区12与保持电容13电连接的状态下是可以处理的量的情况下(第三前提的情况下：参照图5)，在时刻t03，由于从光电转换元件11溢出的信号电荷已经积累在浮动扩散区12和保持电容13中，因此对应于与第一前提或第二前提同样的暗电流和热噪声以及溢出的信号电荷的输出(像素信号)作为第一信号和第二信号存储于存储器8。
另外，在时刻t05，传输晶体管14导通，光电转换元件11中积累的信号电荷从该光电转换元件11传输到浮动扩散区12，但由于光电转换元件11处于满状态，因此第三信号为光电转换元件11饱和的状态的信号。
另外，在时刻t07，在所有信号电荷(光电转换元件11中积累的信号电荷和从光电转换元件11溢出的信号电荷)以添加到初始的暗电流和热噪声的形式被浮动扩散区12和保持电容13保持(积累)的状态下，浮动扩散区12的电压从源极跟随电路SF读出，该被读出的像素信号作为第四信号记录于存储器8。
另外，在时刻t08获得的第五信号是与光电转换元件11中积累的信号电荷无关的复位电平(像素10的复位信号)。
在上述第三前提的情况下，通过信号处理部7从第四信号中减去第五信号等(参照图6的第三信号处理)，从而恢复由像素10光电转换的最终信号(信号X)。详细内容如下。
与第一前提及第二前提的情况不同，在第三前提的情况下，第一信号是包含从光电转换元件11溢出的信号电荷的信号，因此无法作为基准的复位电平使用。因此，从源极跟随电路SF读出包含在积累期间ΔT期间由光电转换元件11产生的所有信号电荷的信号之后，在时刻t08，像素10再次初始化，再次初始化后读出的像素信号作为复位电平(第五信号)记录于存储器8。
该复位电平(第五信号)由于浮动扩散区12和保持电容13在时刻t08变为低阻抗状态后处于浮置 状态，因此与从第一信号读出到第四信号时的复位电平不同。因此，在第五信号中，由电容值和温度、玻尔兹曼常数确定的热噪声的影响、以及在积累期间ΔT期间的暗电流及其散粒噪音的影响无法被忽略。
但是，通过使光电转换元件11的电容被设定为比浮动扩散区12的电容(处理信号量)足够大(在本实施方式的例中为2倍以上)，并且浮动扩散区12与保持电容13的组合电容(处理信号量)被设定为比光电转换元件11的电容足够大(在本实施方式的例子中为1.5倍以上)，从而前述的热噪声、积累期间ΔT的暗电流及其散粒噪音变得足够小于与光电转换元件11中积累的信号电荷有关的信号中包含的散粒噪音。由此，可以充分抑制对具备固体拍摄装置1的智能手机、摄像头等中的最终图像的画质的影响。其结果是，通过信号处理部7从第四信号中减去第五信号等(参照图6的第三信号处理)，从而恢复由像素10光电转换后的最终信号(信号X)。
如上所述，为了恢复在像素10中被光电转换后的最终信号，在本实施方式的固体拍摄装置1中，信号处理部7进行根据上述前提(第一～第三前提)的信号处理(运算)。详细内容如下。
在从某个像素10读出各像素信号(第一～第五信号)后，将该像素信号存储于存储器8，针对各像素10的转换结果，在信号处理部7中进行逐一处理、并行处理以及管道处理等。
在此，如图6所示，本实施方式的存储器8具有：第一信号存储部801，其存储第一信号；第二信号存储部802，其存储第二信号；第三信号存储部803，其存储第三信号；第四信号存储部804，其存储第四信号；第五信号存储部805，其存储第五信号；偏移量存储部820，其存储考虑了暗电流的偏移(任意)值；第一增益存储部831，其存储第一增益系数，该第一增益系数调整信号，使得固体拍摄装置1中的相对于光输入的信号输出单调且连续地变化；第二增益存储部832，其存储用于调整电荷电压转换增益的第二增益系数。
另外，存储器8还具有存储第一阈值的第一阈值存储部841、以及存储第二阈值的第二阈值存储部842。
该第一阈值是至少基于光电转换元件11的电容设定的值。详细地，第一阈值是在由光电转换元件11的电容确定的最大的信号量中考虑了检测偏差或光电转换元件11的个体偏差而设定的值。例如，本实施方式的第一阈值是小于图7中信号Y的信号量饱和时的光量的值(第二区间与第三区间的边界位置)并且与和设定在上述饱和时的光量附近的纵线(单点划线)的交点对应的信号量的值。在此，图7是表示在将横轴设为向像素输入的光量并将纵轴设为信号X、Y、Z的信号量(像素信号量)时的输入输出特性的图表。
另外，第二阈值是至少基于浮动扩散区12的电容设定的值。详细地，第二阈值是在由浮动扩散区12的电容确定的最大的信号量中考虑了检测偏差或光电转换元件11的个体偏差而设定的值。例如，本实施方式的第二阈值是小于信号Z的信号量饱和时的光量的值(第一区间与第二区间的边界位置)并且与和设定在上述饱和时的光量的附近的纵线(单点划线)的交点对应的信号量的值。
返回到图6，具体地说，在信号处理部7，针对每个像素10的像素信号(第一～第五信号)，运算部71根据存储器8的第三信号存储部803中存储的第三信号与第二信号存储部802中存储的第二信号的差分算出信号(第二差分信号)Z(第一信号处理)，使存储器8的第四信号存储部804中存储的第四信号与第一信号存储部801中存储的第一信号的差分乘以第二增益存储部832中存储的第二增益系数，从而算出信号(第一差分信号)Y(第二信号处理)，在将存储器8的第四信号存储部804中存储的第四信号与第五信号存储部805中存储的第五信号的差分和偏移量存储部820中存储的偏移值相加之后，乘以第一增益存储部831中存储的第一增益系数，从而算出信号(第三差分信号)X(第三信号处理)。由上述运算部71算出的信号X、信号Y、信号Z被输入到最终输出前的选择器73中，等待输出指示。
这样，当在运算部71中算出信号X、信号Y、信号Z时，判断部72首先将信号X与第一阈值存储部841中存储的第一阈值进行比较，在信号X大于第一阈值时，指示将信号X输出到选择器73。
在上述信号X与第一阈值的比较中，当信号X为第一阈值以下时，判断部72接下来将信号Y与第二阈值存储部842中存储的第二阈值进行比较，当信号Y大于第二阈值时，指示将信号Y输出到选择器73。
在上述信号Y与第二阈值的比较中，当信号Y为第二阈值以下时，判断部72指示将信号Z输出到选择器73。
当通过判断部72使上述任意指示(输出指示指令)输入到选择器73中时，选择器73基于输入的指示输出信号X、信号Y、信号Z中的任意一个信号(处理结果)。
在此，说明上述判断部72的判断顺序。
如图7所示，由于在读出第四信号时的饱和，信号Y的信号量在第四区间中随着输入的光量的增加而减少。另外，信号Z的信号量在第二区间饱和，在第三区间以后随着光量的增加而减少。
因此，在判断部72，当使用信号Y或信号Z作为判断的条件分支的第一条件时，满足条件的像素 信号量(即，成为相同信号量的输入的光量)存在于输入的光量少的区间时以及输入的光量多的区间时的两个不连续的区间(参照图7中的表示信号量A的双点划线与表示信号Y的线的两个交点a1、a2、以及表示信号量B的线与表示信号Z的线的两个交点b1、b2)，因此，不知道选择了哪个区间的条件(上述两个交点的哪一个)，由此会产生判断错误(伪判定)。因此，本实施方式的判断部72将没有信号量减少的区间的信号X用作最初的判断基准，之后，利用信号Y防止产生上述判断错误。
此外，上述的判断顺序并不是必须的，例如，在由于已知输入到像素10的光量等而没有发生错误的判断(上述的伪判定)的情况下，也可以将信号Y等用于判断的条件分支的第一条件。
以上的固体拍摄装置1具备：光电转换元件11，其根据输入的光，通过光电转换产生信号电荷；浮动扩散区12，其将信号电荷转换为与该信号电荷的量相应的电压；保持电容13，其连接浮动扩散区12，并且能够积累从光电转换元件11溢出的信号电荷；以及信号处理部7，其处理基于浮动扩散区12转换的电压的信号。并且，该信号处理部7具有多个使用保持电容13读出的像素信号的处理单元。
该固体拍摄装置1在输入到光电转换元件11的光的光量(输入的光量)大的范围(例如，图7中的第三区间)内，通过保持电容13积累从光电转换元件11溢出的信号电荷，从而实现高动态范围，同时通过输出由根据与输入到光电转换元件11的光的光量(由光电转换元件产生的电荷的量)的信号处理生成的信号，适当地抑制SN比的图表中的不连续的位置(光量)的间隙(图8的图表中的不连续部分的上下方向的间隔)G1、G2，由此，抑制了由于配置有该固体拍摄装置1的摄像头等的最终图像中的该间隙G1、G2导致的画质下降。详细内容如下。
即使光电转换元件11由于光的输入而产生的信号电荷超过该光电转换元件11的电容而溢出，保持电容13也会积累该溢出的信号电荷，并在从浮动扩散区12读出由光电转换元件11产生的信号电荷时读出该保持电容13中积累的信号电荷，从而实现光电转换元件11的电容以上的输入动态范围(即，高动态范围)。
另外，针对使用保持电容13读出由光电转换元件11产生的信号电荷时的像素信号，在信号处理部7通过多个处理单元适当地进行信号处理，从而能适当地抑制SN比的图表中的不连续的位置(光量)处的间隙G1、G2(参照图8)。
另外，在本实施方式的固体拍摄装置1中，信号处理部7的上述多个处理单元包含相关双采样、以及基于保持电容13复位时的电压的信号的校正。
这样，对使用保持电容13读出由光电转换元件11产生的信号电荷的信号进行相关双采样(例如，通过运算部71从第三信号中减去第二信号的处理(参照图6的第一信号处理)或从第四信号中减去第一信号的处理(参照图6的第二信号处理))等，由此，该信号不受在光电转换元件11积累信号电荷的过程中(即，在积累期间ΔT期间)产生的暗电流或保持电容13产生的热噪声的影响或该影响被充分抑制。
另外，当输入的光的光量大且从光电转换元件11溢出信号电荷时，虽然能对使用积累有该溢出的信号电荷的保持电容13读出由光电转换元件11产生的信号电荷进行基于保持电容13的复位时的电压的校正(例如，通过运算部71从第四信号中减去第五信号的处理(参照图6的第三信号处理)等，但该被校正的信号受到由光电转换元件11产生的暗电流或保持电容13产生的热噪声等的影响。
但是，对于上述溢出的光量，由于被读出的信号(信号电荷的电荷数)大，因此在该信号中暗电流或热噪声的影响相对变小，由此，抑制了SN比的图表中的不连续位置(上述开始溢出的位置)的间隙G2(参照图8)。
详细地，本实施方式的信号处理部7在积累期间ΔT期间光输入到光电转换元件11而生成的信号电荷没有从该光电转换元件11溢出的第一状态时(即，输入的光量为图7中与第一阈值对应的光量的左侧的范围，图8中间隙G2的左侧的范围)，针对浮动扩散区12转换增益不同的像素信号，分别进行相关双采样，在积累期间ΔT期间光输入到光电转换元件11而生成的信号电荷从该光电转换元件11溢出的第二状态时(即，输入的光量为图7中从与第一阈值对应的光量至第三区间与第四区间的边界的范围，在图8中，从间隙G2到SN比的绘制的右端的范围)，针对上述像素信号，基于保持电容的复位时的电压进行校正。
这样，对于光电转换元件11产生的信号电荷的从浮动扩散区12的以不同的转换增益的读出(例如，高转换增益，即浮动扩散区12与保持电容13电断开的状态下的读出、以及低转换增益，即浮动扩散区12与保持电容13电连接的状态下的读出)，均可以进行相关双采样。因此，上述读出的像素信号不受在光电转换元件11积累信号电荷的过程中产生的暗电流或保持电容产生的热噪声的影响或该影响被充分抑制。由此，抑制了SN比的图表中的不连续位置(转换增益切换的位置)的间隙G1(参照图8)。
另一方面，虽然能基于保持电容13的复位时(图3～图5的时刻t08中的复位晶体管16的导通以及关断时)的电压校正从光电转换元件11溢出信号电荷的状态(第二状态)下的读出信号(像素信号)， 但由于无法进行相关双采样，因此该读出信号会受到由光电转换元件11产生的暗电流或保持电容13产生的热噪声等的影响。但是，对于上述溢出的光量，由于被读出的像素信号(电荷数)大，因此在该像素信号中暗电流或热噪声的影响相对变小，由此，抑制了SN比的图表中的不连续位置(上述开始溢出的位置)的间隙G2(参照图8)。
如上所述，根据本实施方式的固体拍摄装置1，在SN比的图表中不连续位置处的各间隙G1、G2分别被抑制(换言之，变小)，因此，有效地抑制了在配置有固体拍摄装置1的摄像头等的最终图像中由于该间隙G1、G2导致的画质下降。
更具体地说，本实施方式的固体拍摄装置1具备：传输晶体管(第一开关晶体管)14，其连接光电转换元件11与浮动扩散区12；保持开关晶体管(第二开关晶体管)15，其连接浮动扩散区12与保持电容13；复位晶体管(第三开关晶体管)16，其连接保持电容13与复位电源(复位电位)VDD1；以及控制部6，其控制各开关晶体管14、15、16。并且，浮动扩散区12还依次经保持开关晶体管15和复位晶体管16与复位电源VDD1连接。
另外，该固体拍摄装置1的信号处理部7在光输入到积累期间ΔT期间的光电转换元件11之后，将从传输晶体管14、保持开关晶体管15、复位晶体管16为关断的状态开始在保持开关晶体管15被控制部6导通时的基于浮动扩散区12的电压的信号作为第一信号，在得到第一信号后，将保持开关晶体管15被控制部6关断时的基于浮动扩散区12的电压的信号作为第二信号，在得到第二信号后，将传输晶体管14被控制部6导通以及关断时的基于浮动扩散区12的电压的信号作为第三信号，在得到第三信号后，将在保持开关晶体管15被控制部6导通的状态下传输晶体管14导通以及关断时的基于浮动扩散区12的电压的信号作为第四信号，在得到第四信号后，将在保持开关晶体管15被控制部6导通的状态下复位晶体管16导通以及关断时的基于浮动扩散区12的电压的信号作为第五信号时，基于上述第一～第五信号生成从该固体拍摄装置1输出到外部的输出信号(信号X、信号Y、信号Z)。
这样，通过在光电转换元件11的一次电荷积累(输入一次光)中获得五个信号(第一～第五信号)，可以根据输入的光的光量(由光电转换元件11产生的电荷的量)应对通过相关双采样的信号处理、以及基于保持电容13的复位时(图3～图5中的时刻t08的复位晶体管16的导通以及关断时)的电压进行校正的信号处理中的任意一个信号处理。
此外，在本实施方式的固体拍摄装置1中，相关双采样分别包含于基于第四信号和第一信号的差分获得信号Y的运算(第三信号处理)、以及基于第三信号和第二信号的差分获得信号Z的运算(第一信号处理)中。另外，基于保持电容13的复位时的电压的校正包含于基于第四信号和第五信号的差分获得信号X的运算(第二信号处理)中。
另外，本实施方式的固体拍摄装置1具备存储器(存储部)8，存储器(存储部)8存储基于光电转换元件11的电容设定的第一阈值、以及基于浮动扩散区12的电容设定的第二阈值。并且，信号处理部7将信号X的值与第一阈值进行比较，当信号X的值大于第一阈值时，将该信号X作为输出信号输出，作为将信号X的值与第一阈值进行比较的结果，当信号X的值为第一阈值以下时，将将信号Y的值与第二阈值进行比较，当信号Y的值大于第二阈值时，将该信号Y作为输出信号输出，作为将信号Y的值与第二阈值进行比较的结果，当信号Y的值为第二阈值以下时，将信号Z作为输出信号输出。
这样，信号处理部7使用两个阈值选择(判断)要输出的信号X、Y、Z，从而更可靠地进行根据输入到光电转换元件11的光的光量(由光电转换元件11产生的信号电荷的量)的信号处理，即通过相关双采样的信号处理与基于保持电容13的复位时的电压进行校正的信号处理的切换或通过这些处理生成的信号的选择等。
在使用现有的Dual conversion gain的固体拍摄装置中，无法获得超过光电转换元件的电容的输入动态范围，在具备横向溢出存储电容的固体拍摄装置中，由于在积累期间ΔT期间产生的暗电流、以及为了得到横向溢出存储电容的复位电平的复位读出从而产生的热噪声等使得SN比劣化，但如上所述，本实施方式的固体拍摄装置1不将保持电容13用作双重转换增益(Dual Conversion Gain)，而是将其用作横向溢出存储电容，通过在新的像素驱动时间点(即，像素10中的各晶体管14～16的新驱动时间点)并在信号处理部7进行规定的信号处理，从而实现比光电转换元件11的电容大的输入动态范围(高动态范围)，同时可以减轻所得到的像素信号中的横向溢出存储电容(保持电容13)中积累的暗电流所带来的影响、以及复位噪音所带来的影响。
另外，可以通过使光电转换元件11的电容(饱和电荷)大于浮动扩散区12的电容来提高该效果。
接着，参照图9～图13来说明本发明的第二实施方式，对于与上述第一实施方式同样的构成使用相同的附图标记，并且省略其详细的说明，仅对不同的构成进行详细说明。
[拍摄装置的构成例]
本实施方式的拍摄装置也与第一实施方式的拍摄装置同样地，例如是智能手机或数码摄像头，固体 拍摄装置1嵌入拍摄装置中，并包含CMOS图像传感器(固体拍摄元件)。
嵌入该拍摄装置的固体拍摄装置1A具备与第一实施方式的固体拍摄装置1同样的构成。即，如图9所示，固体拍摄装置1A具备像素阵列部2、垂直驱动部3、多个列信号处理部4、水平驱动部5、控制部6、信号处理部7以及存储器8A。
在本实施方式的固体拍摄装置1A中，同样地，像素阵列部2具有二维配置成矩阵状的多个像素10A，信号处理部7具有运算部71A、判断部72A和选择器73(参照图12)。
[像素的构成]
接下来，参照图10说明在像素阵列部2配置成矩阵状的像素10A的具体结构。
像素10A具备光电转换元件11、浮动扩散区12、与第一实施方式的保持电容相同的构成(电容)的第一保持电容13、以及与第一保持电容13不同的第二保持电容13A。
另外，像素10A具备：传输晶体管(第一开关晶体管)14，其连接光电转换元件11与浮动扩散区12；第一保持开关晶体管(第二开关晶体管)15，其连接浮动扩散区12与保持电容13；复位晶体管(第三开关晶体管)16，其连接第二保持电容13A与复位电源(复位电位)VDD1；第二保持开关晶体管(第四开关晶体管)15A，其连接第一保持电容13与第二保持电容13A；放大晶体管17，其将浮动扩散区12的电压信号进行放大；以及选择晶体管18，其连接放大晶体管17与列信号线22。
与第一实施方式同样地，浮动扩散区12将由光电转换元件11产生的信号电荷进行电荷电压转换为电压信号并输出。本实施方式的浮动扩散区12依次经第一保持开关晶体管15和第二保持开关晶体管15A与第二保持电容13A连接。另外，该浮动扩散区12依次经第一保持开关晶体管15、第二保持开关晶体管15A以及复位晶体管16与复位电源VDD1连接。
第一保持电容13和第二保持电容13A分别为电容器，与第一实施方式的保持电容13同样地，分别能够积累从光电转换元件11溢出的信号电荷。具体地说，当信号电荷从光电转换元件11溢出时，该信号电荷首先积累到第一保持电容13。并且，第一保持电容13也溢出之后，该溢出的信号电荷积累到第二保持电容13A中。
另外，第一保持电容13还依次经第二保持开关晶体管15A和复位晶体管16与复位电源VDD1连接。该第一保持电容13比第二保持电容13A小。详细地，第一保持电容13能够积累(保持)的信号电荷的电容小于第二保持电容13A能够积累(保持)的信号电荷的电容。
对第一保持开关晶体管15的栅极电极施加驱动信号φS。该驱动信号φS基于来自控制部6的信号从垂直驱动部3输出。当驱动信号φS变为Hi(即，第一保持开关晶体管15导通)时，第一保持开关晶体管15的第一保持栅极变为导通状态，来自浮动扩散区12的信号电荷可以移动到第一保持电容13。此外，当驱动信号φS变为Low时，第一保持开关晶体管15关断。另外，即使第一保持开关晶体管15关断，也会调整第一保持开关晶体管15的保持栅极(势垒)，以在信号电荷从光电转换元件11溢出时积累到第一保持电容13中。本实施方式的第一保持开关晶体管15是与第一实施方式的保持开关晶体管相同的构成。
对第二保持开关晶体管15A的栅极电极施加驱动信号φS1。该驱动信号φS1基于来自控制部6的信号从垂直驱动部3输出。当驱动信号φS1变为Hi(即，第二保持开关晶体管15A导通)时，第二保持开关晶体管15A的第二保持栅极变为导通状态，如果第一保持开关晶体管15导通，则来自浮动扩散区12的信号电荷可以移动到第二保持电容13A。此外，当驱动信号φS1变为Low时，第二保持开关晶体管15A关断。另外，即使第二保持开关晶体管15A关断，也会调整第二保持开关晶体管15A的第二保持栅极(势垒)，以在信号电荷从光电转换元件11溢出并且也从第一保持电容13溢出时积累到第二保持电容13A中。
在本实施方式的复位晶体管16中，当驱动信号φRES变为Hi，该复位晶体管16导通时，根据施加到第一保持开关晶体管15的栅极电极的驱动信号φS、以及施加到第二保持开关晶体管15A的栅极电极的驱动信号φS1，浮动扩散区12、第一保持电容13以及第二保持电容13A的的电位、第一保持电容13和第二保持电容13A的电位、或者第二保持电容13A的电位被复位成复位电源(复位电位)VDD1的电平(复位电平)。
[固体拍摄装置的像素的驱动例]
另外参照图11说明上述构成的像素10A的驱动时间点。
首先，在时刻t01，在选择晶体管18为关断的状态下，传输晶体管14、第一保持开关晶体管15、第二保持开关晶体管15A、复位晶体管16导通，浮动扩散区12、第一保持电容13以及第二保持电容13A变为复位电平。
这样，在浮动扩散区12连接到复位电源VDD1的状态下传输晶体管14关断，由此光电转换元件11变为浮置状态，在光电转换元件11中开始积累通过光的输入产生的信号电荷。
几乎在传输晶体管14关断的同时(详细地，稍有延迟)，第一保持开关晶体管15、第二保持开关晶体管15A、复位晶体管16分别关断，由此，浮动扩散区12、第一保持电容13以及第二保持电容13A也变为浮置状态。由此，在信号电荷从光电转换元件11溢出的(溢出来)情况下，浮动扩散区12、第一保持电容13以及第二保持电容13A可以保持(积累)该溢出来的信号电荷。
这样，在传输晶体管14、第一保持开关晶体管15、第二保持开关晶体管15A以及复位晶体管16关断后，从经过规定的积累期间ΔT之后的时刻t02开始读出该像素10的像素信号。
具体地说，当从像素10A的各晶体管14～16、18为关断的状态开始，控制部6(详细地，经垂直驱动部3的控制部6)使驱动信号φSEL变为Hi从而将选择晶体管18导通时，该像素10与列信号线22连接。
之后，控制部6使驱动信号φS变为Hi，将第一保持开关晶体管15导通，由此浮动扩散区12与第一保持电容13电连接。由此，将浮动扩散区12和第一保持电容13中的热噪声电荷、以及由于光电转换元件11中的信号电荷的积累期间产生的暗电流而产生的暗电流电荷等混合，此时的浮动扩散区12的电压(保持电容基准电位)从出现于源极跟随电路SF的时刻t03起经过有限的时间从该源极跟随电路SF读出，在A/D转换之后，作为第一信号(像素信号)存储于存储器8A。
本实施方式的固体拍摄装置1A也与第一实施方式的固体拍摄装置1同样地，在列信号处理部4，在A/D转换后的状态(即，转换为数字信号的状态)下，第一信号存储于存储器8A，但不限于该构成。也可以在从源极跟随电路SF读出的像素信号(浮动扩散区12的电压)保持为模拟信号的同时进行之后的各处理。此外，在之后的时间点从源极跟随电路SF读出的像素信号(第二～第五信号)也是同样的。
接着，在时刻t04，控制部6使驱动信号φS变为Low，将第一保持开关晶体管15关断，将浮动扩散区12与第一保持电容13电断开。在该状态下，浮动扩散区12的电位(浮动扩散区基准电位)从源极跟随电路SF读出，在A/D转换之后作为第二信号(像素信号)存储于存储器8A。该第二信号还包含存储于第一保持开关晶体管15的暗电流成分。
接着，在时刻t05，控制部6使驱动信号φTX变为Hi，将传输晶体管14导通，将光电转换元件11在积累期间ΔT期间积累的信号电荷传输到浮动扩散区12，之后将驱动信号φTX变为Low，将传输晶体管14关断。
该信号在时刻t06从源极跟随电路SF读出，在A/D转换之后作为第三信号(像素信号)存储于存储器8A。
接着，在时刻t17，控制部6使驱动信号φS变为Hi，使第一保持开关晶体管15导通，从而使浮动扩散区12和第一保持电容13导通后，再次使驱动信号φTX变为Hi以及Low，将传输晶体管14导通以及关断。此时的浮动扩散区12的电压从源极跟随电路SF读出，在A/D转换之后作为第四信号(像素信号)存储于存储器8A。
这样，在时刻t17，在光电转换元件11中积累的信号电荷传输到第一保持电容13后，在时刻t18，控制部6使驱动信号φS1变为Hi，将第二保持开关晶体管15A导通，从而使浮动扩散区12以及第一保持电容13、第二保持电容13A导通。并且，控制部6从该状态起再次使驱动信号φTX变为Hi以及Low，从而使传输晶体管14导通以及关断。此时的浮动扩散区12的电压从源极跟随电路SF读出，在A/D转换之后作为第十五信号(像素信号)存储于存储器8A。此时，在积累期间ΔT期间从光电转换元件11溢出来的信号电荷积累到第二保持电容13A的情况下(第四前提)，该信号电荷包含于第十五信号中。
接着，在时刻t19，控制部6使驱动信号φRES变为Hi，将复位晶体管16导通，将浮动扩散区12、第一保持电容13以及第二保持电容13A连接到复位电源(复位电位)VDD1，将浮动扩散区12、第一保持电容13以及第二保持电容13A的的信号电荷全部初始化。该被初始化的浮动扩散区12、第一保持电容13以及第二保持电容13A的电压(复位电平)从源极跟随电路SF读出，在A/D转换之后作为第十六信号(像素信号)存储于存储器8A。
最后，在时刻t1A，控制部6使驱动信号φS1变为Low并将第二保持开关晶体管15A关断，从而第一保持电容13与第二保持电容13A分开的状态下的浮动扩散区12和第一保持电容13的电压(复位电平)从源极跟随电路SF读出，在A/D转换之后作为第十七信号(像素信号)存储于存储器8A。
在本实施方式的固体拍摄装置1A中，为了恢复在像素10中被光电转换后的最终信号，信号处理部7进行根据上述前提(第一～第四前提)的信号处理。详细内容如下。
在从某个像素10读出各像素信号(第一～第四信号以及第十五～第十七信号)后，将该像素信号存储于存储器8A，针对各像素10的转换结果，在信号处理部7中进行逐一处理、并行处理以及管道处理等。
在此，如图12所示，本实施方式的存储器8A具有：第一信号存储部801，其存储第一信号；第二信号存储部802，其存储第二信号；第三信号存储部803，其存储第三信号；第四信号存储部804，其存储第四信号；第十五信号存储部815，其存储第十五信号；第十六信号存储部816，其存储第十六信号；第十七信号存储部817，其存储第十七信号；第一偏移量存储部821，其存储考虑了第一保持电容13的暗电流的第一偏移值(任意)；第二偏移量存储部822，其同样地存储考虑了第二保持电容13A的暗电流的第二偏移值；第一增益存储部831，其存储用于调整电荷电压转换增益的第一增益系数；第二增益存储部832，其存储用于调整电荷电压转换增益的第二增益系数；以及第三增益存储部833，其存储用于调整电荷电压转换增益的第三增益系数。另外，存储器8A具有存储第一阈值存储部841、第二阈值存储部842、第三阈值的第三阈值存储部843。该第三阈值至少基于浮动扩散区12的电容、第一保持电容13以及第二保持电容13A设定。具体地说，第三阈值例如是第二保持电容13A饱和的信号量。
具体地说，在信号处理部7，针对每个像素10的像素信号(第一～第四信号、第十五～第十七信号)，信号处理部7的运算部71A将存储器8A的第十五信号存储部815中存储的第十五信号与第十六信号存储部816中存储的第十六信号的差分和第二偏移量存储部822中存储的第二偏移值相加之后，乘以第三增益存储部833中存储的第三增益系数，从而算出信号(第四差分信号)α(第四信号处理)，根据存储器8A的第三信号存储部803中存储的第三信号与第二信号存储部802中存储的第二信号的差分算出信号(第二差分信号)Z(第一信号处理)，使存储器8A的第四信号存储部804中存储的第四信号与第一信号存储部801中存储的第一信号的差分乘以第二增益存储部832中存储的第二增益系数，从而算出信号(第一差分信号)Y(第二信号处理)，在将存储器8A的第四信号存储部804中存储的第四信号与第十七信号存储部817中存储的第十七信号的差分和第一偏移量存储部821中存储的第一偏移值相加之后，乘以第一增益存储部831中存储的第一增益系数(第三信号处理)，从而算出信号(第三差分信号)X。上述通过运算部71A算出的信号α、信号X、信号Y、信号Z被输入到最终输出前的选择器73中，等待输出指示。
这样，当在运算部71A算出信号α、信号X、信号Y、信号Z时，判断部72A首先将信号α与第三阈值存储部843中存储的第三阈值进行比较，当信号α大于第三阈值时，指示将信号α输出到选择器73。
在将该信号α与第三阈值的比较中，当信号α为第三阈值以下时，判断部72A接下来将信号X与第一阈值存储部841中存储的第一阈值进行比较，当信号X大于第一阈值时，指示将信号X输出到选择器73。
在该信号X与第一阈值的比较中，当信号X为第一阈值以下时，判断部72A接下来将信号Y与第二阈值存储部842中存储的第二阈值进行比较，当信号Y大于第二阈值时，指示将信号Y输出到选择器73。
在该信号Y与第二阈值的比较中，当信号Y为第二阈值以下时，判断部72A指示将信号Z输出到选择器73。
当通过判断部72A将上述任意指示(输出指示指令)输入到选择器73时，选择器73基于输入的指示输出信号α、信号X、信号Y、信号Z中的任意一个信号(处理结果)。
此外，在上述判断部72A的判断中，也与第一实施方式的判断部72的判断同样地，以防止信号Z和信号Y的伪判定的顺序进行判断。
本实施方式的固体拍摄装置1A具备：第二保持电容13A，其与第一保持电容13不同，能够积累从光电转换元件11溢出的信号电荷；传输晶体管(第一开关晶体管)14，其连接光电转换元件11与上述浮动扩散区12；第一保持开关晶体管(第二开关晶体管)15，其连接浮动扩散区12与保持电容13；复位晶体管(第三开关晶体管)16，其连接第二保持电容13A与复位电源(复位电位)VDD1；以及第二保持开关晶体管(第四开关晶体管)15A，其连接第一保持电容13与第二保持电容13A。并且，浮动扩散区12依次经第一保持开关晶体管15和第二保持开关晶体管15A与第二保持电容13A连接。而且，浮动扩散区12依次经第一保持开关晶体管15、第二保持开关晶体管15A以及复位晶体管16与复位电源VDD1连接。另外，第一保持电容13依次经第二保持开关晶体管15A和复位晶体管16与复位电源VDD1连接。
另外，该固体拍摄装置1A的信号处理部7在光输入到积累期间ΔT期间的光电转换元件11之后，将基于从传输晶体管14、保持开关晶体管15、第二保持开关晶体管15A、复位晶体管16为关断的状态开始在第一保持开关晶体管15被控制部6导通时的浮动扩散区12的电压的信号作为第一信号，在得到第一信号后，将基于第一保持开关晶体管15被控制部6关断时的浮动扩散区12的电压的信号作为第二信号，在得到第二信号后，将基于传输晶体管14被控制部6导通以及关断时的浮动扩散区12的电压的信号作为第三信号，在得到第三信号后，将基于在保持开关晶体管15被控制部6导通的状态下传输晶 体管14导通以及关断时的浮动扩散区12的电压的信号作为第四信号，在得到第四信号后，将基于在保持开关晶体管15以及第二保持开关晶体管15A被控制部6导通的状态下传输晶体管14导通以及关断时的浮动扩散区12的电压的信号作为第十五信号，在得到第十五信号后，将基于在第一保持开关晶体管15以及第二保持开关晶体管15A被控制部6导通的状态下复位晶体管16导通以及关断时的浮动扩散区12的电压的信号作为第十六信号，在得到第十六信号后，将基于在第一保持开关晶体管15被控制部6导通的状态下第二保持开关晶体管15A关断时的浮动扩散区12的电压的信号作为第十七信号时，基于上述第一～第四信号以及第十五～第十七信号生成从该固体拍摄装置1A输出到外部的输出信号(信号α、信号X、信号Y、信号Z)。
上述构成的本实施方式的固体拍摄装置1A在输入到光电转换元件11的光的光量大的范围内，通过第一保持电容13或第二保持电容13A积累从光电转换元件11溢出的信号电荷，从而实现高动态范围，同时通过输出由根据与输入到光电转换元件11的光的光量(光电转换元件11产生的信号电荷的量)的信号处理生成的信号，适当地抑制SN比的图表中的不连续的位置(光量)的间隙G1、G2、G3(参照图13)，由此，抑制了由于配置有该固体拍摄装置1A的摄像头等的最终图像中的该间隙G1、G2、G3导致的画质下降。
另外，像素10A除了具备第一保持电容13外，还具备第二保持电容13A，即具备多个保持电容，因此，相比于仅具备一个保持电容的像素，能够积累从光电转换元件11溢出的信号电荷的电容较大，因此，动态范围更大。
并且，当输入到像素10A(光电转换元件11)的光是第二保持电容13A开始积累从光电转换元件11溢出的信号电荷的光量时，在SN比的图表中产生不连续性，不连续位置中的间隙G3为比较大的间隙(图13参照)，但由于是SN比的绝对值大的位置处的间隙，因此在配置该固体拍摄装置1A的摄像头等中的最终图像中，间隙G3导致的视觉影响微弱。
另外，如上所述，通过在光电转换元件11的一次电荷积累(输入一次光)中获得七个信号(第一～第四信号以及第十五～第十七信号)，可以根据输入的光的光量(由光电转换元件11产生的信号电荷的量)应对通过相关双采样的信号处理、以及基于保持电容(第一保持电容13、第二保持电容13A)的复位时的电压进行校正的信号处理中的任意一个信号处理。
并且，具备能够积累从光电转换元件11溢出的信号电荷的多个保持电容(在本实施方式的例子中为第一保持电容13和第二保持电容13A这两个保持电容)，通过根据由光电转换元件11产生的信号电荷的量来调整所使用的保持电容的数量，能够抑制由于热噪声等的保持电容导致的画质下降。即，由于保持电容越大，引起噪音的热噪声等越大，因此，在使用第一保持电容13积累由光电转换元件11产生的信号电荷而不使用第二保持电容的情况下，相比于通过一个保持电容确保相同电容(第一保持电容13和第二保持电容13A的总计电容)的构成，可以抑制由热噪声等保持电容导致的画质下降。
此外，在本实施方式的固体拍摄装置1A中，相关双采样分别包含于获得基于第四信号和第一信号的差分的信号(第一差分信号)Y的运算(第二信号处理)、以及获得基于第三信号和第二信号的差分的信号(第二差分信号)Z的运算(第一信号处理)中。另外，基于保持电容(第一保持电容13、第二保持电容13A)的复位时的电压的校正包含于获得基于第四信号和第十七信号的差分的信号(第三差分信号)X的运算(第三信号处理)、以及获得基于第十五信号和第十六信号的差分的信号(第四差分信号)α的运算(第四信号处理)中。
另外，本实施方式的固体拍摄装置1A具备存储器(存储部)8A，存储器(存储部)8A存储至少基于光电转换元件11的电容设定的第一阈值、以及至少基于浮动扩散区12的电容设定的第二阈值。并且，信号处理部7将信号(第四差分信号)α的值与第三阈值进行比较，当信号α的值大于第三阈值时，将该信号α作为输出信号输出，作为将信号α的值与第三阈值进行比较的结果，当信号α的值为第三阈值以下时，将将信号(第三差分信号)X的值与第一阈值进行比较，当信号X的值大于第一阈值时，将该信号X作为输出信号输出，作为将信号X的值与第一阈值进行比较的结果，当信号X的值为第一阈值以下时，将信号(第一差分信号)Y的值与第二阈值进行比较，当信号Y的值大于第二阈值时，将该信号Y作为输出信号输出，作为将信号Y的值与第二阈值进行比较的结果，当信号Y的值为第二阈值以下时，将信号(第二差分信号)Z作为输出信号输出。
这样，信号处理部7使用三个阈值选择要输出的信号α、X、Y、Z，从而更可靠地进行根据输入到光电转换元件11的光的光量(由光电转换元件11产生的电荷的量)的信号处理，即通过相关双采样的信号处理与基于保持电容(第一保持电容13、第二保持电容13A)的复位时的电压进行校正的信号处理的切换或通过这些处理生成的信号的选择等。
另外，在本实施方式的固体拍摄装置1A中，第一保持电容13小于第二保持电容13A。
随着保持电容中积累的信号电荷的数量增多，针对与从保持电容读出的上述电荷的数量相应的信号 的噪音(由热噪声等保持电容引起的噪音)的相对大小被抑制，即，上述噪音对画质的影响被抑制。因此，通过减少在来自光电转换元件11的信号电荷的数量小时使用的第一保持电容13，以抑制在仅使用该第一保持电容13时由该第一保持电容13产生的噪音，并且增大在来自光电转换元件11的信号电荷的数量变多且上述噪音对画质的影响相对变小时使用的第二保持电容13A，能够实现高动态范围，并能够适当地抑制由于保持电容引起的画质的下降。
如上所述，本实施方式的固体拍摄装置1A也与第一实施方式的固体拍摄装置1同样地，不是将第一保持电容13以及第二保持电容13A用作Dual Conversion Gain，而是将其用作横向溢出存储电容，通过在新的像素驱动时间点(即，像素10中的各晶体管14～16的新的驱动时间点)并在信号处理部7进行规定的信号处理，从而实现比光电转换元件11的电容大的输入动态范围(高动态范围)，同时可以减轻所得到的像素信号中的横向溢出存储电容(第一保持电容13以及第二保持电容13A)中积累的暗电流所带来的影响、以及复位噪音所带来的影响。
另外，与第一实施方式的固体拍摄装置1同样地，可以通过使光电转换元件11的电容(饱和电荷)大于浮动扩散区12的电容来提高该效果。
此外，本发明的固体拍摄装置、以及具备固体拍摄装置的拍摄装置不限于上述实施方式，毋庸置疑，在不脱离本发明的主旨的范围内可以进行各种变更。例如，可以在某实施方式的构成中追加其他实施方式的构成，还可以将某实施方式的构成的一部分置换为其他实施方式的构成。而且，还可以删除某实施方式的构成的一部分。
上述第一以及第二实施方式的固体拍摄装置1、1A中包含的CMOS图像传感器至少具有像素阵列部2、垂直驱动部3、多个列信号处理部4、水平驱动部5以及控制部6，但不限于该构成。CMOS图像传感器(固体拍摄元件)可以包含信号处理部7或存储器8。即，通过运算处理部算出的各信号(第一～第五信号或第一～第四以及第十五～第十七信号)可以构成为存储(保持)于嵌入有像素信号的读出电路、DSP以及固体拍摄装置的智能手机或摄像头等的系统中。
另外，信号处理部7中的信号处理(信号的乘法累加运算，使用阈值的判断等)的具体构成不受限制。例如，在信号处理部7，可以在阈值前后在信号之间进行加权加法，进行信号处理，使得基于读出差异的噪音的差异在缓慢的浓淡变化部中不明显，也可以进行使用二次函数的增益或查表等的信号处理而不是简单的一次函数的增益。即，在信号处理部7，进行什么样的阈值判断和乘法累加运算是适宜选择，信号处理部7可以构成为使用阈值判断和乘法累加运算等将五个信号(第一～第五信号)或七个信号(第一～第四信号、以及第十五～第十七信号)制作为一个最终信号。
另外，在上述第一以及第二实施方式的固体拍摄装置1、1A中，在由于光的输入而从光电转换元件溢出信号电荷的情况下，用于像素信号的校正的保持电容13、13A的复位电平(复位时的电压：在第一以及第二实施方式的例子中为第五信号第十六信号)在第四信号或第十五信号之后立即获得，即，针对光电转换元件11的光的每一次输入而进行，但不限于该构成。例如，也可以构成为在初始阶段获得保持电容的上述复位电平，上述获得的复位电平作为已知的值，在每次光输入的光电转换元件11时使用。
为了表示本发明，在上述参照附图的同时，通过实施方式适当且充分地说明了本发明，但是本领域技术人员应该认识到，能够容易地进行上述实施方式的变更和/或改良。因此，只要本领域技术人员实施的变更方式或改良方式不是脱离权利要求书所记载的权利要求的权利范围，则该变更方式或该改良方式被解释为包含在该权利要求书的权利范围内。
附图标记说明：
1、1A…固体拍摄装置，2…像素阵列部，21…行信号线，22…列信号线，3…垂直驱动部，4…列信号处理部，5…水平驱动部，6…控制部，7…信号处理部，71、71A…运算部，72，72A…判断部，73…选择器，8，8A…存储器(存储部)，801…第一信号存储部，802…第二信号存储部，803…第三信号存储部，804…第四信号存储部，805…第五信号存储部，815…第十五信号存储部，816…第十六信号存储部，817…第十七信号存储部，820…偏移量存储部，821…第一偏移量存储部，822…第二偏移量存储部，831…第一增益存储部，832…第二增益存储部，833…第三增益存储部，841…第一阈值存储部，842…第二阈值存储部，843…第三阈值存储部，10、10A…像素，11…光电转换元件，12…浮动扩散区，13…保持电容，第一保持电容，13A…第二保持电容，14…传输晶体管(第一开关晶体管)，15…保持开关晶体管，第一保持开关晶体管(第二开关晶体管)，15A…第二保持开关晶体管(第四开关晶体管)，16…复位晶体管(第三开关晶体管)，17…放大晶体管，18…选择晶体管，500…固体拍摄装置，501…像素，502…光电二极管，503…浮动扩散区，504…横向溢出存储电容，505…开关晶体管，G1、G2、G3…间隙，SF…源极跟随电路，VDD1…复位电源(复位电位)，VDD2…电源，X…信号(第三差分信号)，Y…信号(第一差分信号)，Z…信号(第二差分信号)，α…信号(第四差分信号)，φRES、φS、φS1、 φSEL，φTX…驱动信号

Claims (11)

  1. 一种固体拍摄装置，其特征在于，具备：
    光电转换元件，其根据输入的光，通过光电转换产生电荷；
    浮动扩散区，其将所述电荷转换为与该电荷的量相应的电压；
    保持电容，其连接所述浮动扩散区，并且能够积累从所述光电转换元件溢出的所述电荷；以及
    信号处理部，其处理基于在所述浮动扩散区转换的所述电压的信号，
    所述信号处理部具有所述信号的多个处理单元，所述信号是使用所述保持电容读出的。
  2. 根据权利要求1所述的固体拍摄装置，其中，
    所述多个处理单元包含相关双采样单元、以及基于所述保持电容的复位时的电压对信号进行校正的校正单元。
  3. 一种固体拍摄装置，其特征在于，具备：
    光电转换元件，其根据输入的光，通过光电转换产生电荷；
    浮动扩散区，其将所述电荷转换为与该电荷的量相应的电压；
    保持电容，其连接所述浮动扩散区，并且能够积累从所述光电转换元件溢出的所述电荷；以及
    信号处理部，其处理基于在所述浮动扩散区转换的所述电压的信号，
    所述信号处理部，
    当处于所述光输入到所述光电转换元件而生成的所述电荷没有从该光电转换元件溢出的第一状态时，对在所述浮动扩散区中的转换增益不同的所述信号分别进行相关双采样，
    当处于所述光输入到所述光电转换元件而生成的所述电荷从该光电转换元件溢出的第二状态时，基于所述保持电容的复位时的电压对所述信号进行校正。
  4. 根据权利要求2或3所述的固体拍摄装置，其中，具备：
    第一开关晶体管，其连接所述光电转换元件与所述浮动扩散区；
    第二开关晶体管，其连接所述浮动扩散区与所述保持电容；
    第三开关晶体管，其连接所述保持电容与复位电位；以及
    控制部，其控制各开关晶体管，
    所述浮动扩散区依次经由所述第二开关晶体管和所述第三开关晶体管与所述复位电位连接，
    所述信号处理部，
    在所述光输入到所述光电转换元件后，将基于从所述第一～第三开关晶体管关断的状态开始在所述第二开关晶体管被所述控制部导通时的所述浮动扩散区的电压的信号作为第一信号，
    在得到所述第一信号后，将基于所述第二开关晶体管被所述控制部关断时的所述浮动扩散区的电压的信号作为第二信号，
    在得到所述第二信号后，将基于所述第一开关晶体管被所述控制部导通以及关断时的所述浮动扩散区的电压的信号作为第三信号，
    在得到所述第三信号后，将基于所述第二开关晶体管被所述控制部导通的状态下所述第一开关晶体管导通以及关断时的所述浮动扩散区的电压的信号作为第四信号，
    在得到所述第四信号后，将基于所述第二开关晶体管被所述控制部导通的状态下所述第三开关晶体管导通以及关断时的所述浮动扩散区的电压的信号作为第五信号时，
    基于所述第一～第五信号生成从该固体拍摄装置输出到外部的输出信号。
  5. 根据权利要求4所述的固体拍摄装置，其中，
    所述相关双采样分别包含于基于所述第四信号和所述第一信号的差分获得第一差分信号的信号处理、以及基于所述第三信号和所述第二信号的差分获得第二差分信号的信号处理中，
    基于所述保持电容的复位时的电压的校正包含于基于所述第四信号和所述第五信号的差分获得第三差分信号的信号处理中。
  6. 根据权利要求5所述的固体拍摄装置，其中，
    具备存储部，其存储至少基于所述光电转换元件的电容设定的第一阈值以及至少基于所述浮动扩散区的电容设定的第二阈值，
    所述信号处理部，
    将所述第三差分信号的值与所述第一阈值进行比较，当所述第三差分信号的值大于所述第一阈值时，将该第三差分信号作为所述输出信号输出，
    作为将所述第三差分信号的值与所述第一阈值进行比较的结果，当所述第三差分信号的值为所述第一阈值以下时，将所述第一差分信号的值与所述第二阈值进行比较，当所述第一差分信号的值大于所述第二阈值时，将该第一差分信号作为所述输出信号输出，
    作为将所述第一差分信号的值与所述第二阈值进行比较的结果，当所述第一差分信号的值为所述第二阈值以下时，将所述第二差分信号作为所述输出信号输出。
  7. 根据权利要求2或3所述的固体拍摄装置，其中，具备：
    第二保持电容，其与作为所述保持电容的第一保持电容不同，能够积累从所述光电转换元件溢出的所述电荷；
    第一开关晶体管，其连接所述光电转换元件与所述浮动扩散区；
    第二开关晶体管，其连接所述浮动扩散区与所述保持电容；
    第三开关晶体管，其连接所述第二保持电容与复位电位；
    第四开关晶体管，其连接所述第一保持电容与所述第二保持电容；以及
    控制部，其控制各开关晶体管，
    所述浮动扩散区依次经由所述第二开关晶体管和所述第四开关晶体管与所述第二保持电容连接，并且依次经由所述第二开关晶体管、所述第四开关晶体管、以及所述第三开关晶体管与所述复位电位连接，
    所述第一保持电容依次经由所述第四开关晶体管和所述第三开关晶体管与所述复位电位连接，
    所述信号处理部，
    在所述光输入到所述光电转换元件后，将基于从所述第一～第四开关晶体管关断的状态开始在所述第二开关晶体管被所述控制部导通时的所述浮动扩散区的电压的信号作为第一信号，
    在得到所述第一信号后，将基于所述第二开关晶体管被所述控制部关断时的所述浮动扩散区的电压的信号作为第二信号，
    在得到所述第二信号后，将基于所述第一开关晶体管被所述控制部导通以及关断时的所述浮动扩散区的电压的信号作为第三信号，
    在得到所述第三信号后，将基于在所述第二开关晶体管被所述控制部导通的状态下所述第一开关晶体管导通以及关断时的所述浮动扩散区的电压的信号作为第四信号，
    在得到所述第四信号后，将基于在所述第二开关晶体管以及所述第四开关晶体管被所述控制部导通的状态下所述第一开关晶体管导通以及关断时的所述浮动扩散区的电压的信号作为第十五信号，
    在得到所述第十五信号后，将基于在所述第二开关晶体管以及所述第四开关晶体管被所述控制部导通的状态下所述第三开关晶体管导通以及关断时的所述浮动扩散区的电压的信号作为第十六信号，
    在得到所述第十六信号后，将基于在所述第二开关晶体管被所述控制部导通的状态下所述第四开关晶体管关断时的所述浮动扩散区的电压的信号作为第十七信号时，
    基于所述第一～第四信号以及第十五～第十七信号生成从该固体拍摄装置输出到外部的输出信号。
  8. 根据权利要求7所述的固体拍摄装置，其中，
    所述相关双采样分别包含于基于所述第四信号和所述第一信号的差分获得第一差分信号的信号处理、以及基于所述第三信号和所述第二信号的差分获得第二差分信号的信号处理中，
    基于所述保持电容的复位时的电压的校正分别包含于基于所述第四信号和所述第十七信号的差分获得第三差分信号的信号处理、以及基于所述第十五信号和所述第十六信号的差分获得第四差分信号的信号处理中。
  9. 根据权利要求8所述的固体拍摄装置，其中，
    具备存储部，其存储至少基于所述光电转换元件的电容设定的第一阈值、至少基于所述浮动扩散区的电容设定的第二阈值、以及至少基于所述浮动扩散区的电容以及所述第一保持电容设定的第三阈值，
    所述信号处理部，
    将所述第四差分信号的值与所述第三阈值进行比较，当所述第四差分信号的值大于所述第三阈值时，将该第四差分信号作为所述输出信号输出，
    作为将所述第四差分信号的值与所述第三阈值进行比较的结果，当所述第四差分信号的值为所述第三阈值以下时，将所述第三差分信号的值与所述第一阈值进行比较，当所述第三差分信号的值大于所述第一阈值时，将该第三差分信号作为所述输出信号输出，
    作为将所述第三差分信号的值与所述第一阈值进行比较的结果，当所述第三差分信号的值为所述第一阈值以下时，将所述第一差分信号的值与所述第二阈值进行比较，当所述第一差分信号的值大于所述第二阈值时，将该第一差分信号作为所述输出信号输出，
    作为将所述第一差分信号的值与所述第二阈值进行比较的结果，当所述第一差分信号的值为所述第二阈值以下时，将所述第二差分信号作为所述输出信号输出。
  10. 根据权利要求7～9中任一项所述的固体拍摄装置，其中，
    所述第一保持电容小于所述第二保持电容。
  11. 一种拍摄装置，其中，
    所述拍摄装置具备根据权利要求1～10中任一项所述的固体拍摄装置。
PCT/CN2022/084177 2022-03-30 2022-03-30 固体拍摄装置、以及具备固体拍摄装置的拍摄装置 WO2023184265A1 (zh)

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