[go: up one dir, main page]

WO2018056051A1 - Élément d'imagerie, procédé de fonctionnement d'élément d'imagerie, dispositif d'imagerie et dispositif électronique - Google Patents

Élément d'imagerie, procédé de fonctionnement d'élément d'imagerie, dispositif d'imagerie et dispositif électronique Download PDF

Info

Publication number
WO2018056051A1
WO2018056051A1 PCT/JP2017/032019 JP2017032019W WO2018056051A1 WO 2018056051 A1 WO2018056051 A1 WO 2018056051A1 JP 2017032019 W JP2017032019 W JP 2017032019W WO 2018056051 A1 WO2018056051 A1 WO 2018056051A1
Authority
WO
WIPO (PCT)
Prior art keywords
detection unit
power supply
illuminance
unit
error
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2017/032019
Other languages
English (en)
Japanese (ja)
Inventor
健之 青木
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sony Semiconductor Solutions Corp
Original Assignee
Sony Semiconductor Solutions Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sony Semiconductor Solutions Corp filed Critical Sony Semiconductor Solutions Corp
Publication of WO2018056051A1 publication Critical patent/WO2018056051A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
    • H04N25/77—Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components

Definitions

  • the present disclosure relates to an imaging device, an imaging device operation method, an imaging device, and an electronic device, and more particularly, an imaging device, an imaging device operation method, an imaging device, and an imaging device that can improve response speed and measurement accuracy at low illuminance. It relates to electronic equipment.
  • CMOS Complementary Metal Oxide Semiconductor
  • the photodiode generates a very small current, and the minute current is converted into a voltage.
  • the voltage is converted with high accuracy due to variations in transistor manufacturing. For example, FPN (Fixed Pattern Noise) due to this may occur.
  • the imaging device for vehicle use such as an image used for automatic driving of a vehicle or a mirror image such as a mirrorless vehicle does not function sufficiently.
  • the present disclosure has been made in view of such a situation, and in particular, allows the image sensor to function with sufficient response speed and measurement accuracy even under low illumination.
  • An imaging device includes a pixel including an array of photodiodes that accumulates electric charges according to the amount of incident light, a power supply unit connected to the photodiodes, and
  • the image sensor includes an error detection unit that detects an output error of the power supply unit by comparing an output with a reference potential, and an illuminance detection unit that detects illuminance based on an operating frequency of the error detection unit.
  • the illuminance detection unit can determine the load current value of the logarithmic transistor based on the operating frequency of the error detection unit, and detect the illuminance according to the load current value.
  • the power supply unit can be a DCDC power supply including a charge pump circuit or a switching regulator circuit.
  • the illuminance detection unit may include a pulse counter that counts the pulse count of the pulse signal output from the error detection unit, and the error detection unit includes the charge pump circuit, or It can be an error amplifier in the switching regulator circuit, the error detection result of the output of the power supply unit is output as a pulse signal by comparing the output of the power supply unit and a reference potential, and the illuminance detection unit Based on the pulse count number, the operating frequency by PFM (Pulse ⁇ ⁇ ⁇ Frequency Modulation) control can be obtained and detected as the illuminance.
  • PFM Pulse ⁇ ⁇ ⁇ Frequency Modulation
  • a temperature measuring unit that measures the environmental temperature and a duty correction unit that switches the duty of the charge pump circuit and corrects the temperature based on the environmental temperature can be further included.
  • a temperature correction table showing a duty for each environmental temperature may be further included, and the duty correction unit reads a duty corresponding to the environmental temperature from the temperature correction table, and the charge pump circuit The duty can be switched to the read duty and the temperature can be corrected.
  • a temperature measuring unit that measures the environmental temperature and a bias correcting unit that switches the bias current of the logarithmic transistor and corrects the temperature based on the environmental temperature can be further included.
  • a temperature correction table indicating a bias current value for each environmental temperature can be further included, and the bias correction unit reads a bias current value corresponding to the environmental temperature from the temperature correction table.
  • the bias current of the logarithmic transistor can be switched to the read bias current value for temperature correction.
  • a storage unit that stores the pulse count number in units of frames and for each column by a plurality of frames, and inter-frame difference detection that calculates a difference between the pulse count numbers between the plurality of frames as an inter-frame difference.
  • a motion detection unit that detects a motion of an image captured by the pixel array based on the inter-frame difference.
  • An analog-to-digital conversion unit that performs analog-to-digital conversion on a pixel signal generated based on the charge accumulated by the photodiode can be further included, and when the illuminance is lower than a predetermined illuminance,
  • the error detection unit is configured to detect an output error of the power supply unit by comparing the output of the power supply unit with a reference potential, and the illuminance detection unit is configured to detect the illuminance based on an operating frequency of the error detection unit.
  • the storage unit stores the number of pulse counts in units of frames and for each column by a number of frames, and the inter-frame difference detection unit stores the number of frames between the plurality of frames.
  • the difference between the pulse counts is obtained as an inter-frame difference, and the motion detector is imaged by the pixel array based on the inter-frame difference.
  • the analog-to-digital conversion unit performs analog-to-digital conversion on a pixel signal generated based on the charge accumulated by the photodiode. can do.
  • An operation method of an imaging device includes a pixel that is configured by an array of photodiodes that accumulates electric charges according to the amount of incident light, a power supply unit connected to the photodiodes, Imaging including an error detection unit that detects an output error of the power supply unit by comparing the output of the power supply unit with a reference potential, and an illuminance detection unit that detects the illuminance based on an operating frequency of the error detection unit
  • the error detection unit detects an error in the output of the power supply unit by comparing the output of the power supply unit with a reference potential
  • the illuminance detection unit operates the error detection unit.
  • An imaging device includes a pixel formed of an array of photodiodes that accumulates electric charges according to the amount of incident light, a power supply unit connected to the photodiodes,
  • the imaging apparatus includes an error detection unit that detects an output error of the power supply unit by comparing an output with a reference potential, and an illuminance detection unit that detects illuminance based on an operating frequency of the error detection unit.
  • An electronic apparatus includes a pixel including an array of photodiodes that accumulates electric charges according to the amount of incident light, a power supply unit connected to the photodiodes, An electronic device includes an error detection unit that detects an output error of the power supply unit by comparing an output with a reference potential, and an illuminance detection unit that detects illuminance based on an operating frequency of the error detection unit.
  • charges corresponding to the amount of incident light are accumulated by pixels including photodiodes arranged in an array, and an error detection unit outputs an output from a power supply unit connected to the photodiodes.
  • An error in the output of the power supply unit is detected by comparison with a reference potential, and the illuminance is detected by the illuminance detection unit based on the operating frequency of the error detection unit.
  • the imaging device it is possible to cause the imaging device to function with sufficient response speed and measurement accuracy even under low illuminance.
  • FIG. 1 illustrates a configuration example of an image sensor to which the technology of the present disclosure is applied.
  • a power supply unit 39 a current detection unit 40, a temperature correction unit 41, a current value storage unit 42, and a frame difference detection unit 43.
  • the pixel array 31 has, for example, m rows ⁇ n columns of pixels arranged in an array. Each pixel generates a charge corresponding to the amount of incident light and outputs a pixel signal.
  • the pixel signal of each pixel is transferred via the transfer lines 30-1 to 30-n. If it is not necessary to distinguish each of the pixels 50-1 to 50-p, the pixel 50-1 is simply referred to as the pixel 50, and the other configurations are also referred to in the same manner.
  • the pixel 50 is provided with a photodiode 51, a transfer transistor 52, a reset transistor 53, an FD (floating diffusion) 54, an amplification transistor 55, and a selection transistor 56.
  • the photodiode 51 has a charge corresponding to the amount of incident light. Accumulate.
  • the transfer transistor 52 transfers the charge accumulated in the photodiode 51 to the FD 54.
  • the reset transistor 53 resets the photodiode 51 by resetting the FD 54 and cooperating with the transfer transistor 52.
  • the FD (floating diffusion) 54 is connected to the gate of the amplification transistor 55.
  • the amplifying transistor 55 is connected to the gate of the FD 54 and outputs a pixel signal by amplifying the power supply voltage according to the electric charge accumulated in the FD 54.
  • the selection transistor 56 is turned on when the pixel 50 to be transferred in units of rows is selected, and the pixel signal is output to the comparator 33 via the vertical transfer line 30.
  • the illuminance detection unit 32 is provided corresponding to each pixel 50, and has a configuration in which Logarithmic pixel circuits (logarithmic transistor: Log Tr) including a diode-connected transistor is connected to the photodiode 51. Therefore, a weak change in illuminance is detected on the basis of the conducting current value.
  • Logarithmic transistor logarithmic transistor: Log Tr
  • the detailed configuration of the illuminance detection unit 32 will be described later with reference to FIG.
  • the comparator 33 compares pixel signals supplied in units of rows from the vertical transfer lines 30-1 to 30-n provided for the columns of the pixels 50-1 to 50-p and a reference (not shown), The comparison result is supplied to the counter 34.
  • the counter 34 counts a count value corresponding to the reference supplied to the comparator 33, and outputs a count value at a timing when the comparison result of the comparator 33 changes, so that the analog signal is converted into a digital signal together with the comparator 33. It functions as a digital converter, and outputs the pixel signal converted into a digital signal to the Hi-Speed I / F 35.
  • the Hi-Speed I / F 35 outputs the pixel signal converted into the digital signal to the image processing device (not shown), the frame difference detection unit 43, and the motion detection unit 36 as imaging data.
  • the motion detection unit 36 detects motion based on the difference result supplied from the frame difference detection unit 43 in accordance with the timing at which image data is supplied from the Hi-Speed I / F 35 in the imaging mode described later. Then, the motion detection result is output to an image processing device (not shown) and the sensor control unit 37. Further, in the case of a sensor mode, which will be described later, the motion detection unit 36 detects a motion based on the difference result supplied from the frame difference detection unit 43, and an image processing device (not shown) and a sensor control unit. To 37.
  • the sensor control unit 37 outputs an instruction signal for switching the drive mode to the sensor drive unit 38 based on the motion detection result supplied from the motion detection unit 36. More specifically, the operation mode of the image sensor 11 includes an imaging mode in which a high-definition image is captured by each pixel 50 of the pixel array 31 and a sensor mode in which the illuminance detection unit 32 detects the presence or absence of motion even at low illuminance. is there.
  • the sensor control unit 37 controls the sensor mode to detect the presence or absence of motion at low illuminance, and when motion is detected in the sense mode, shifts the operation mode to the imaging mode, and again no motion is detected in the imaging mode. When the state is low and the illuminance is low, the mode is shifted to the sense mode.
  • the sensor drive unit 38 operates each pixel 50 of the pixel array 31 or the illuminance detection unit 32 in an operation mode based on an instruction signal from the sensor control unit 37.
  • the power supply unit 39 supplies power to the pixels 50-1 to 50-p and the illuminance detection units 32-1 to 32-n of the pixel array 31.
  • the power supply unit 39 includes an error amplifier 82 (FIG. 4), compares the feedback potential (VFB) with the reference potential, detects an error when the feedback potential is lower than the reference potential, and operates the error amplifier 82.
  • the signal is output as a signal to the timing control unit 83 (FIG. 4) and the current detection unit 40.
  • the current detection unit 40 detects an error signal of the error amplifier 82, detects the operation frequency as a digital signal of a detection current corresponding to the illuminance of the illuminance detection unit 32, and stores it in the current value storage unit 42 in units of frames. .
  • the temperature correction unit 41 performs temperature correction related to the measurement of the current value by the current detection unit 40 based on the operation signal of the error amplifier 82 supplied from the power supply unit 39.
  • the detailed configuration of the temperature correction unit 41 will be described later with reference to FIG.
  • the frame difference detection unit 43 obtains an inter-frame difference between images captured by the pixels 50 of the pixel array 31 supplied from the Hi-Speed I / F 35 and supplies the inter-frame difference to the motion detection unit 36. To do. Further, when in the sensor mode, the frame difference detection unit 43 obtains an inter-frame difference between current values stored in the current value storage unit 42 for each frame, and supplies the obtained inter-frame difference to the motion detection unit 36. To do.
  • the illuminance detection unit 32 operates in a sensor mode for the purpose of detecting illuminance under low illuminance. More specifically, the illuminance detection unit 32 includes a logarithmic transistor 61, an amplification transistor 62, a selection transistor 63, and a bias transistor 64, which are transistors that are diode-connected to the photodiode 51.
  • the functions of the amplification transistor 62 and the selection transistor 63 are basically the same as those of the amplification transistor 55 and the selection transistor 56.
  • the logarithmic transistor 61 is supplied with power from the power supply unit 39 from a gate terminal that is diode-connected.
  • the power supply unit 39 compares the reference voltage with the feedback voltage by the built-in error amplifier 82 (FIG. 4). If the feedback voltage is lower than the reference voltage, an error signal indicating an error is output as a pulse signal. Thus, the voltage is boosted by the charge pump circuit 84 to make the voltage constant.
  • the current detection unit 40 counts the frequency of occurrence of the error signal by the pulse counter 101 (FIG. 4), thereby measuring the frequency from the count value as a frequency. The current value under illuminance is output as a digital signal.
  • the bias transistor 64 applies a bias according to the temperature by the bias control unit 122 (FIG. 4) in the temperature correction unit 41.
  • the conventional illuminance detection unit 32 detects the illuminance based on the voltage amplified by the amplification transistor 62 using the current value between the logarithmic transistor 61 and the photodiode 51. It was.
  • a parasitic capacitance Cx is generated by the wiring between the photodiode 51 and the gate of the amplification transistor 62 in the figure, so that a minute current generated by the low illuminance is expressed by the logarithmic transistor.
  • it is used in a so-called weak inversion region. For this reason, since charging takes time due to the parasitic capacitance Cx, the response is poor, and if it is used as an image used for automatic driving or a mirror image in a mirrorless vehicle, it is generated for the behavior of the vehicle. The response of the image to be delayed is delayed, and there is a risk that the safety may be hindered.
  • the pulse signal generated as the error signal of the error amplifier 82 is counted, and the operation frequency of the error amplifier 82 based on the count result is used to obtain the digital signal Is measured and used as illuminance.
  • DCDC circuit 4 is a so-called DCDC circuit, and includes a power supply 81, an error amplifier 82, a timing control unit 83, and a charge pump circuit 84.
  • the power source 81 is a DC power source that generates power required for each pixel 50 of the pixel array 31.
  • the error amplifier 82 compares the reference potential from the power supply 81 with the potential of the feedback power supply that is the output of the charge pump circuit 84, and generates an error signal when the feedback power supply is smaller than the power supply 81 based on the comparison result. And output to the timing controller 83 and the current detector 40.
  • the timing control unit 83 controls the operation of the charge pump circuit 84 at the timing when the error signal is generated, and generates power so as to compensate for the lowered voltage. At this time, the timing control unit 83 controls the operation of the charge pump circuit 84 by the duty set corresponding to the environmental temperature from the duty correction unit 121 of the temperature correction unit 41.
  • the current detection unit 40 includes a pulse counter 101, counts pulse signals composed of error signals, and uses the operation frequency of the error amplifier 82 per unit time, that is, the operation frequency as a current value for the last two frames.
  • the current value is stored in the current value storage unit 42 in units of columns.
  • the current value storage unit 42 stores a pulse count value of the (N ⁇ 1) th frame as a current value for each column (Line) of the N ⁇ 1th frame (N ⁇ 1 frame).
  • 141-1 and a storage unit 141-2 that stores a pulse count value of the Nth frame as a current value for each column (Line) of the Nth frame (N frame).
  • the storage units 141-1 and 141-2 discard the pulse count value of the old frame and store the pulse count value of the new frame.
  • the temperature correction unit 41 measures the environmental temperature at which the image sensor 11 operates, and corrects the duty of the charge pump circuit 84 of the power supply unit 39 and the bias current by the bias transistor 64 according to the environmental temperature. More specifically, the temperature correction unit 41 includes a duty correction unit 121, a bias correction unit 122, a temperature correction table 123, and a temperature measurement unit 124.
  • the duty correction unit 121 reads the corresponding duty correction value from the temperature correction table 123 based on the environmental temperature measured by the temperature measurement unit 124, and controls the timing control unit 83 of the power supply unit 39 to control the charge pump circuit. 84 is operated by correcting the duty according to the environmental temperature.
  • the bias correction unit 122 reads the corresponding bias current value from the temperature correction table 123 based on the environmental temperature measured by the temperature measurement unit 124, and controls the bias transistor 64 that controls the current value flowing through the logarithmic transistor 61.
  • the bias current is corrected according to the environmental temperature.
  • the temperature correction table 123 is a table in which optimum duty and bias current values are recorded with respect to the environmental temperature obtained in advance.
  • the temperature measurement unit 124 measures the environmental temperature, measures the environmental temperature of the image sensor 11, and supplies the measured temperature to the duty correction unit 121 and the bias correction unit 122.
  • the frame difference detection unit 43 obtains an inter-frame difference from the difference between the current values for the two most recent frames stored in the current value storage unit 42 and outputs the difference to the motion detection unit 36.
  • the motion detection unit 36 regards that the motion has occurred in the image, detects the motion, and supplies the sensor control unit 37 with information indicating that the motion has been detected. Based on the information indicating that this movement has been detected, the sensor control unit 37 switches the drive mode of the sensor drive unit 38 from the sensor mode at the time of low illuminance to the imaging mode.
  • a current is generated in proportion to the amount of light even at low illuminance, but the voltage value is a so-called weak value as shown by a range surrounded by a one-dot chain line. Since it is an inversion region and is easily affected by temperature characteristics, it is difficult to measure a voltage value with high accuracy. Therefore, it is very difficult to measure the amount of light using the voltage value at low illuminance.
  • the illuminance is measured based on the current value based on the operating frequency of the error amplifier 82 of the power supply unit 39 (the operating frequency of the charge pump circuit 84).
  • the illuminance is measured by the voltage value of the logarithmic transistor 61. Note that the method of measuring the light amount by the voltage value applied to the logarithmic transistor 61 is a general method, and therefore only a description at low illuminance will be given here.
  • ⁇ Parasitic capacitance> As described above, when the illuminance is low, the logarithmic transistor 61 is a weak inversion region. For this reason, as shown in FIG. 6, in the connection relationship with the illuminance detection unit 32 of the pixels 50-1 to 50-m connected to one vertical transfer line 30, a parasitic is applied in units of columns by an infinite number of wirings. A capacitance Cx (similar to the parasitic capacitance Cx in FIG. 2) is generated.
  • the frame frequency is regulated by the time constant according to the parasitic capacitance Cx, and it becomes difficult to read the current in HFR (High Frame Rate).
  • HFR High Frame Rate
  • this current varies depending on the current below the threshold Vth, and is difficult to manage in the manufacturing of the logarithmic transistor 61.
  • FPN Fixed Pattern Noise
  • Ipd is a current value generated according to the amount of light received by the photodiode 51
  • Id0 is a current value when a threshold Vth at which the logarithmic transistor 61 is switched on or off is applied
  • kb is a Boltzmann constant.
  • n is the number of electrons
  • q is the amount of charge
  • T is the absolute temperature.
  • the voltage value Vout is generally a function of temperature, and the characteristics greatly depend on the environmental temperature. Is done.
  • FIG. 7 shows the illuminance (light intensity) and voltage value received by the photodiode 51 at an ambient temperature of ⁇ 30 ° C. (one-dot chain line), normal use temperature (Typical) (two-dot chain line), and 105 ° C. (solid line).
  • the relationship with Vout is shown. That is, as shown in FIG. 7, in a predetermined illuminance range, the voltage value decreases as the illuminance increases, and the voltage value increases as the temperature rises. Change with higher sensitivity. On the contrary, the voltage value becomes lower as the temperature becomes lower, and changes with lower sensitivity to the change in illuminance.
  • the imaging device 11 of the present disclosure detects illuminance by reading by IV conversion of the logarithmic transistor 61 at normal illuminance, and illuminance based on the current value from the power supply unit 39 supplied to the logarithmic transistor 61 at low illuminance. Is detected.
  • the characteristic at the time of low illuminance detects the change in illuminance based on the current value based on the operating frequency of the error amplifier 82 in the power supply unit (DCDC power supply) 39.
  • the temperature characteristic of the logarithmic transistor 61 is corrected by changing the duty that is the driving condition of the charge pump circuit 84.
  • the pixel power supply is used as an analog power supply generated by a DCDC circuit inside the sensor.
  • the pixel power supply may be directly supplied from an external power supply, but the mobile device is supplied with pixel power from a battery via a DCDC circuit.
  • the current detection unit 40 is provided for the power supply unit 39, and the current detection unit 40 detects the current value as digital data.
  • the current detection unit 40 is provided with a pulse counter 101 as shown in FIG. 4, and the load current is converted into a digital value by utilizing the relationship between the operating frequency of the error amplifier 82 and the current by PFM control. Convert to and detect.
  • the error amplifier 82 compares the output voltage of the power supply unit 39 with the reference voltage of the power supply 81 as a part of the Feed Back mechanism, and uses a pulse signal as a comparison result to control the charge pump circuit by PFM (Pulse Freqency Modulation) control. 84 operation is controlled.
  • PFM Pulse Freqency Modulation
  • the operating frequency (CP operating frequency) of the charge pump circuit 84 driven by PFM control is proportional to the load current (Iload) of the logarithmic transistor. This relationship is also shown by the following formula (2). That is, as the load current increases, charge is supplied to the charge pump circuit 84, so the operating frequency also increases.
  • C is a charge pump capacitor capacity
  • n is the number of boosting stages
  • Vin is a charge pump power supply
  • Vout is a charge pump boosting output
  • f is an operating frequency of the charge pump circuit 84.
  • the current detection unit 40 uses the pulse counter 101. Is used to detect the count value as a current value and to control the charge pump circuit 84 in the power supply unit 39 and to detect a moving object.
  • the duty here indicates a ratio of a period during which the charge pump circuit 84 is turned on in the one cycle T in which the charge pump circuit 84 controls on and off. It is possible to variably set between 100%.
  • the duty correction unit 121 of the temperature correction unit 41 corrects the current detection result of the current detection unit 40 according to the environmental temperature.
  • the operating frequency (CP operating frequency) of the charge pump circuit 84 relative to the load current (Iload) when driving the charge pump circuit 84 by PFM control is the environmental temperature.
  • this subthreshold slope characteristic is proportional to the temperature.
  • this subthreshold slope characteristic is proportional to the temperature.
  • inclination changes according to environmental temperature in the range of subthreshold slope SS1 to SS2.
  • Cdm is a depletion layer capacitance
  • Cox is an oxide film capacitance
  • q is a charge
  • k is a Boltzmann constant
  • T is an absolute temperature
  • m is 1 + Cdm / Cox.
  • the IV characteristic of the logarithmic transistor is such that the output voltage varies depending on the temperature characteristic, as shown in FIG. .
  • the current value detected by the current detection unit 40 is obtained based on the count value obtained by counting the operating frequency of the charge pump circuit 84 shown as an error signal supplied from the error amplifier 82 by the pulse counter 101. Therefore, the influence of the temperature characteristics of the device such as the diffusion current of the logarithmic transistor 61 can be reduced.
  • temperature correction of the logarithmic transistor 61 is also performed. That is, as shown in the left part of FIG. 10, in the detailed configuration of the illuminance detection unit 32 of FIG. 6, a current source 32a is generally provided downstream of the logarithmic transistor 61. Since the current source 32a operates as a load resistor, the output voltage can be changed by changing the resistance to a variable resistor 32b as shown in the center of FIG.
  • the current value generated by the photodiode 51 can be adjusted by allowing the current value flowing through the variable resistor 32b functioning as the current source 32a to be adjusted as a bias current. Therefore, as shown in the right part of FIG. 10, a bias transistor 64 is provided to function in the same manner as the variable resistor 32 b functioning as the current source 32 a, and the bias correction unit 122 corresponds to the environmental temperature. By adjusting the bias current, the output voltage can be adjusted when the current value generated in the photodiode 51 is converted into a voltage.
  • ⁇ Temperature correction table> In the current detection by the current detection unit 40, it may be assumed that the characteristic of the current value-charge pump operating frequency shifts depending on each environmental temperature condition. Therefore, in the temperature correction table 123, for example, as shown in FIG. A duty for correcting the operating frequency of the charge pump circuit 84 and a bias current are preset and stored for each environmental temperature.
  • the environmental temperature, the corresponding duty, and the bias current value are shown from the left. More specifically, the environmental temperature is described as -30 ° C., -10 ° C.,... 125 ° C. from the top, and D0%, D1%,. As the bias current value, BA0, BA1,... DAn are described.
  • the duty correction unit 121 and the bias correction unit 122 correct the duty and bias current optimum for the environmental temperature based on the information of the temperature correction table 123 as shown in FIG.
  • the operating frequency of the same charge pump can be set, and the illuminance can be appropriately measured by specifying the current value based on the operating frequency without depending on the environmental temperature.
  • the driving mode is assumed to be the sensor mode, and the power as the output of the charge pump circuit 84 is sequentially supplied from the power supply unit 39 to each pixel 50 of the pixel array 31.
  • the error amplifier 82 sequentially compares the reference potential and the feedback potential that is the power output from the charge pump circuit 84. Based on the comparison result, when the feedback potential of the power supplied to the pixel 50 does not reach the reference potential, the error amplifier 82 supplies an error signal to the timing control unit 83, and the charge pump circuit 84 performs PFM control. Then, the process of boosting the output voltage is repeated.
  • the error signal is also supplied to the current detection unit 40, the operating frequency of the error amplifier 82 (charge pump circuit 84) is obtained by the pulse counter 101 of the current detection unit 40, and stored in the current value storage unit 42 as a current value. Is done.
  • step S31 the temperature measurement unit 124 of the temperature correction unit 41 measures the environmental temperature and supplies the measurement result to the duty correction unit 121 and the bias correction unit 122.
  • step S32 the duty correction unit 121 accesses the temperature correction table 123, reads the duty corresponding to the current environmental temperature, and controls the timing control unit 83 to drive the charge pump circuit 84 with the read duty. To do.
  • step S33 the bias correction unit 122 accesses the temperature correction table 123, reads the bias current value corresponding to the current environmental temperature, controls the bias transistor 66, and causes the read bias current value to flow.
  • step S34 the pulse counter 101 of the current detection unit 40 counts the error signal from the error amplifier 82, and uses the pulse count value as the load current value of the logarithmic transistor 61 to store the storage unit 141-1 of the current value storage unit 42.
  • the storage unit 141 in which any one of the oldest data of 141-2 is stored is overwritten by one frame.
  • step S35 the frame difference detection unit 43 obtains a difference between pulse count values corresponding to the current values of the respective frames stored in the storage units 141-1 and 141-2 of the current value storage unit 42, respectively. Find the difference between frames.
  • step S36 the frame difference detection unit 43 compares the difference value, which is the difference between frames, with a predetermined threshold value, and whether the difference value is larger than the predetermined threshold value and whether there is movement in the image. Determine whether or not. If it is determined in step S36 that the interframe difference is greater than the predetermined threshold and a change is detected and there is a motion in the image, the process proceeds to step S37.
  • step S37 the frame difference detection unit 43 notifies the sensor control unit 37 that motion has been detected in the image based on the interframe difference. Based on this notification, for example, the sensor control unit 37 instructs to switch the drive mode of the sensor drive unit 38. If it is determined in step S36 that no motion is detected, the process in step S37 is skipped.
  • step S38 the current detection unit 40 determines whether or not the end of the operation is instructed. If the end is not instructed, the process returns to step S31, and the subsequent processes are repeated. If it is determined in step S38 that the end has been instructed, the process ends.
  • the current value of the logarithmic transistor 61 is obtained as a pixel value according to the operating frequency of the charge pump circuit 84 based on the error signal from the error amplifier 82, thereby detecting motion under low illuminance. Therefore, it is possible to detect at high speed without being affected by the parasitic capacitance Cx or the like.
  • the operating frequency of the error amplifier 82 is A low frequency count value C0 for one frame is counted, and at time T1, this count value C0 is stored. At this time, since there is no previous count value, if the previous operation mode is MODE A, the operation mode is continued.
  • FIG. 13 shows from the top the timing of the vertical synchronization signal VS, the current value of the charge pump circuit 84, the illuminance change image of the input image indicating the illuminance change, the error amplifier operating frequency, the frequency count, and the current value storage unit. A control processing mode corresponding to the storage timing and the current value is shown.
  • the imaging device can detect motion at high speed and with high accuracy even under conditions of low illuminance and changes in environmental temperature. .
  • the drive mode is set to the sensor mode by repeating the series of processes described above until motion is detected under low illumination, and when motion is detected, an image is captured by each pixel 50 of the pixel array 31.
  • the pixel signal is AD-converted using the comparator 33 and the counter 34, so that the pixel signal can be switched to a driving mode for outputting a high-definition image, that is, an imaging mode.
  • the mode may be switched to the sense mode again when the illuminance is lower than the predetermined illuminance and no motion is detected.
  • the drive mode is changed from the imaging mode to the sensor mode without operating the comparator 33 or the counter 34. Therefore, it is possible to realize power saving.
  • the motion can be detected at high speed even under low illuminance, if the motion is detected, the drive mode can be quickly changed from the sensor mode to the imaging mode, and high-speed image processing is required. For example, the function can be sufficiently exhibited even for in-vehicle use.
  • the logarithmic transistor 61 in the column direction is monitored as one current value, and the current value for each pixel 50 unit cannot be detected, but the current value is detected for each column, and the surface Since the influence of the variation in the threshold value Vth for each of the logarithmic transistors 61 is averaged as the charge pump current, the detection stability can be improved.
  • the current detection unit 40 may be integrated in the power supply unit 39.
  • FIG. 14 shows a configuration example of the display device 151 that realizes the OLED ACL.
  • the display device 151 includes an OLED 161, a driver transistor 162, a power supply unit 163, a current detection unit 164, a current value storage unit 165, an ACL 166, a driver 167, and an SPI (Serial Peripheral Interface) 168.
  • OLED 161 emits light by power supplied from the power supply unit 163.
  • the configuration of the power supply unit 163 will be described later in detail with reference to FIG.
  • the current detection unit 164 has basically the same configuration as that of the current detection unit 40, includes a pulse counter 164a, and an error amplifier 173 (see FIG. 15) provided in the power supply unit 163 with the current value supplied to the OLED 161. ) And the count value is stored in the current value storage unit 165 as a current value.
  • the ACL 166 reads the count value stored in the current value storage unit 165 during the vertical blanking period, obtains the current current value, and exceeds the count value corresponding to the current value that is the upper limit value.
  • a command is output to 167 to close the driver transistor 162.
  • the driver 167 controls opening / closing of the driver transistor 162 based on a command from the ACL 166.
  • SPI Serial Peripheral Interface
  • the power supply unit 163 includes a coil 170, a diode 171, a capacitor 172, an error amplifier 173, a reference power output circuit 174, a latch 175, an amplifier circuit 176, an AND circuit 177, an amplifier circuit 178, an LS (Level Shifter) 179, an amplifier circuit 180, VDD 181 and switch 182 are provided.
  • the coil 170, the diode 171, the capacitor 172, the VDD 181 and the switch 182 constitute a switching regulator.
  • the error amplifier 173 compares the potential of the OLED 161 with the reference potential VSS, determines whether the potential of the OLED 161 is higher than the reference potential, and if so, stores a signal indicating that there is no error in the latch 175, When the voltage of the OLED 161 is not higher than the reference potential, an error signal is stored in the latch 175.
  • the latch 175 outputs the pulse counter 164a and the AND circuit 177 in synchronization with the clock control signal.
  • the amplifier circuit 176 amplifies the clock control signal and outputs it to the AND circuit 177.
  • the AND circuit 177 outputs the signal of the error amplifier 173 stored in the latch 175 to the switch 182 via the amplifier circuit 178, the LS (Level Shifter) 179, and the amplifier circuit 180 in synchronization with the clock control signal.
  • the error amplifier 173 compares the potential of the OLED 161 with the reference potential, and adjusts the voltage applied to the VDD 182 by opening and closing the switch 181 according to the comparison result.
  • the error amplifier 173 outputs an error signal to the pulse counter 164a via the latch 175.
  • the pulse counter 164a stores the pulse count value, which is the operating frequency of the error amplifier 173, in the current value storage unit 165 as the current value of the OLED 161.
  • the ACL 166 reads the current value flowing in the current OLED 161 stored in the current value storage unit 165 as a pulse count value, controls the driver 167, and controls the opening and closing of the driver transistor 162. Thus, control is performed so that an excessive current does not flow through the OLED 161.
  • the above-described imaging device can be applied to various electronic devices such as an imaging device such as a digital still camera or a digital video camera, a mobile phone having an imaging function, or other devices having an imaging function.
  • FIG. 16 is a block diagram illustrating a configuration example of an imaging apparatus as an electronic apparatus to which the present technology is applied.
  • An imaging apparatus 201 shown in FIG. 16 includes an optical system 202, a shutter device 203, a solid-state imaging device 204, a drive circuit 205, a signal processing circuit 206, a monitor 207, and a memory 208, and displays still images and moving images. Imaging is possible.
  • the optical system 202 includes one or more lenses, guides light (incident light) from a subject to the solid-state image sensor 204, and forms an image on the light receiving surface of the solid-state image sensor 204.
  • the shutter device 203 is disposed between the optical system 202 and the solid-state imaging device 204, and controls the light irradiation period and the light-shielding period to the solid-state imaging device 204 according to the control of the drive circuit 1005.
  • the solid-state image sensor 204 is configured by a package including the above-described solid-state image sensor.
  • the solid-state imaging device 204 accumulates signal charges for a certain period in accordance with light imaged on the light receiving surface via the optical system 202 and the shutter device 203.
  • the signal charge accumulated in the solid-state image sensor 204 is transferred according to a drive signal (timing signal) supplied from the drive circuit 205.
  • the drive circuit 205 outputs a drive signal for controlling the transfer operation of the solid-state image sensor 204 and the shutter operation of the shutter device 203 to drive the solid-state image sensor 204 and the shutter device 203.
  • the signal processing circuit 206 performs various types of signal processing on the signal charges output from the solid-state imaging device 204.
  • An image (image data) obtained by the signal processing by the signal processing circuit 206 is supplied to the monitor 207 and displayed, or supplied to the memory 208 and stored (recorded).
  • the imaging device 11 illustrated in FIG. 1 of the present disclosure is applied in place of the optical system 202, the shutter device 203, and the solid-state imaging device 204 described above, thereby reducing the Even in illuminance, it is possible to function as a sensor at high speed and with high accuracy.
  • FIG. 17 is a diagram showing a usage example in which the image sensor 11 of FIG. 1 described above is used.
  • the imaging device described above can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays as follows.
  • Devices for taking images for viewing such as digital cameras and mobile devices with camera functions
  • Devices used for traffic such as in-vehicle sensors that capture the back, surroundings, and interiors of vehicles, surveillance cameras that monitor traveling vehicles and roads, and ranging sensors that measure distances between vehicles, etc.
  • Equipment used for home appliances such as TVs, refrigerators, air conditioners, etc. to take pictures and operate the equipment according to the gestures ⁇ Endoscopes, equipment that performs blood vessel photography by receiving infrared light, etc.
  • Equipment used for medical and health care ⁇ Security equipment such as security surveillance cameras and personal authentication cameras ⁇ Skin measuring instrument for photographing skin and scalp photography Such as a microscope to do beauty Equipment used for sports-Equipment used for sports such as action cameras and wearable cameras for sports applications-Used for agriculture such as cameras for monitoring the condition of fields and crops apparatus
  • this indication can also take the following structures.
  • Pixels composed of photodiodes arranged in an array for accumulating charges according to the amount of incident light; A power supply connected to the photodiode; An error detection unit for detecting an output error of the power supply unit by comparing the output of the power supply unit and a reference potential; An illuminance detection unit that detects illuminance based on an operating frequency of the error detection unit.
  • ⁇ 3> The imaging device according to ⁇ 2>, wherein the illuminance detection unit obtains a load current value of the logarithmic transistor based on an operating frequency of the error detection unit, and detects illuminance according to the load current value.
  • the power supply unit is a DCDC power supply including a charge pump circuit or a switching regulator circuit.
  • the illuminance detection unit includes a pulse counter that counts the pulse count of the pulse signal output from the error detection unit,
  • the error detection unit is an error amplifier in the charge pump circuit or the switching regulator circuit, and an error detection result of the output of the power supply unit by comparing the output of the power supply unit with a reference potential is obtained as a pulse signal.
  • Output as The imaging device according to ⁇ 4>, wherein the illuminance detection unit obtains the operating frequency by PFM (Pulse Freqency Modulation) control based on the pulse count and detects the operating frequency.
  • PFM Pulse Freqency Modulation
  • ⁇ 6> a temperature measuring unit for measuring the environmental temperature;
  • the image pickup device according to ⁇ 4>, further including a duty correction unit that performs temperature correction by switching a duty of the charge pump circuit based on the environmental temperature.
  • a temperature correction table indicating a duty for each environmental temperature is further included,
  • the imaging device wherein the duty correction unit reads a duty corresponding to the environmental temperature from the temperature correction table, and switches the duty of the charge pump circuit to the read duty.
  • ⁇ 8> A temperature measurement unit for measuring the environmental temperature;
  • the imaging device according to ⁇ 4>, further including: a bias correction unit that performs temperature correction by switching a bias current of the logarithmic transistor based on the environmental temperature.
  • a temperature correction table indicating a bias current value for each environmental temperature is further included, The bias correction unit reads a bias current value corresponding to the environmental temperature from the temperature correction table, and switches the bias current of the logarithmic transistor to the read bias current value to correct the temperature.
  • a storage unit that stores the pulse count in units of frames and for each column by a plurality of frames, An inter-frame difference detection unit for obtaining a difference between the pulse counts between the plurality of frames as an inter-frame difference;
  • the imaging device according to ⁇ 5>, further including a motion detection unit that detects a motion of an image captured by the pixels based on the inter-frame difference.
  • ⁇ 11> further includes an analog-to-digital converter that performs analog-to-digital conversion on a pixel signal generated based on the charge accumulated by the photodiode;
  • the error detection unit detects an error in the output of the power supply unit by comparing the output of the power supply unit with a reference potential;
  • the illuminance detection unit detects the illuminance based on the operating frequency of the error detection unit,
  • the storage unit stores the pulse count number in units of frames and for each column by a number of frames,
  • the inter-frame difference detection unit obtains the difference in the pulse count number between the plurality of frames as an inter-frame difference,
  • the motion detection unit detects a motion of an image captured by the pixel based on the inter-frame difference;
  • the image sensor according to ⁇ 10>, wherein the analog-to-digital conversion unit performs analog-to-digital conversion on a pixel signal generated based on the charge accumulated by the photo
  • Pixels composed of photodiodes arranged in an array that accumulate electric charges according to the amount of incident light;
  • a power supply connected to the photodiode;
  • An error detection unit for detecting an output error of the power supply unit by comparing the output of the power supply unit and a reference potential;
  • An illuminance detection unit that detects the illuminance based on an operating frequency of the error detection unit, and a method for controlling an image sensor,
  • the error detection unit detects an error in the output of the power supply unit by comparing the output of the power supply unit with a reference potential;
  • the operation method of an image sensor wherein the illuminance detection unit detects the illuminance based on an operating frequency of the error detection unit.
  • Pixels made up of photodiodes arranged in an array for accumulating charges according to the amount of incident light;
  • a power supply connected to the photodiode;
  • An error detection unit for detecting an output error of the power supply unit by comparing the output of the power supply unit and a reference potential;
  • An illuminance detection unit that detects illuminance based on an operating frequency of the error detection unit.
  • Pixels composed of photodiodes arranged in an array for accumulating charges according to the amount of incident light;
  • a power supply connected to the photodiode;
  • An error detection unit for detecting an output error of the power supply unit by comparing the output of the power supply unit and a reference potential;
  • An illuminance detector that detects illuminance based on an operating frequency of the error detector.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Studio Devices (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)

Abstract

La présente invention concerne un élément d'imagerie, un procédé de fonctionnement d'élément d'imagerie, un dispositif d'imagerie et un dispositif électronique, avec lesquels la détection de mouvement peut être effectuée à grande vitesse et avec une précision élevée même lorsqu'il y a une faible luminance. Un amplificateur d'erreur compare un potentiel de référence et le potentiel d'électricité fourni à une photodiode par l'intermédiaire d'un transistor logarithmique, et lorsque le potentiel de référence n'est pas atteint, un signal d'erreur indiquant une erreur est émis sous la forme d'un signal d'impulsion. Un compteur d'impulsions compte les signaux d'erreur et stocke la fréquence de fonctionnement de l'amplificateur d'erreur en tant que valeur actuelle du courant circulant dans le transistor logarithmique sur une base trame par trame. Lorsqu'une différence intertrame est égale ou supérieure à une valeur prescrite, un mouvement est considéré comme ayant été détecté. La présente invention peut s'appliquer à des dispositifs d'imagerie.
PCT/JP2017/032019 2016-09-20 2017-09-06 Élément d'imagerie, procédé de fonctionnement d'élément d'imagerie, dispositif d'imagerie et dispositif électronique Ceased WO2018056051A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016-182640 2016-09-20
JP2016182640 2016-09-20

Publications (1)

Publication Number Publication Date
WO2018056051A1 true WO2018056051A1 (fr) 2018-03-29

Family

ID=61689527

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/032019 Ceased WO2018056051A1 (fr) 2016-09-20 2017-09-06 Élément d'imagerie, procédé de fonctionnement d'élément d'imagerie, dispositif d'imagerie et dispositif électronique

Country Status (1)

Country Link
WO (1) WO2018056051A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003134397A (ja) * 2001-10-24 2003-05-09 Honda Motor Co Ltd 光センサ回路
JP2008192324A (ja) * 2007-01-31 2008-08-21 Sharp Corp 照度センサ及び調光制御装置
JP2010130364A (ja) * 2008-11-27 2010-06-10 Sony Corp タイミング調整回路、固体撮像素子、およびカメラシステム
JP2011160090A (ja) * 2010-01-29 2011-08-18 Sony Corp 画像処理装置、および信号処理方法、並びにプログラム
JP2011160554A (ja) * 2010-02-01 2011-08-18 Sanyo Electric Co Ltd 電源回路及び電子機器

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003134397A (ja) * 2001-10-24 2003-05-09 Honda Motor Co Ltd 光センサ回路
JP2008192324A (ja) * 2007-01-31 2008-08-21 Sharp Corp 照度センサ及び調光制御装置
JP2010130364A (ja) * 2008-11-27 2010-06-10 Sony Corp タイミング調整回路、固体撮像素子、およびカメラシステム
JP2011160090A (ja) * 2010-01-29 2011-08-18 Sony Corp 画像処理装置、および信号処理方法、並びにプログラム
JP2011160554A (ja) * 2010-02-01 2011-08-18 Sanyo Electric Co Ltd 電源回路及び電子機器

Similar Documents

Publication Publication Date Title
US20220060645A1 (en) Imaging apparatus, driving method, and electronic device
JP6838675B2 (ja) 固体撮像装置および電子機器
US10498983B2 (en) Solid-state imaging device, method for driving solid-state imaging device, and electronic apparatus
TWI717450B (zh) 固體攝像裝置、固體攝像裝置之驅動方法、及電子機器
WO2017169216A1 (fr) Élément d'imagerie à semi-conducteurs, procédé de commande d'élément d'imagerie à semi-conducteurs et dispositif électronique
US10785423B2 (en) Image sensor, image capturing apparatus, and image capturing method
JP7174928B2 (ja) 撮像装置およびカメラシステム、ならびに、撮像装置の駆動方法
US7956916B2 (en) Solid-state imaging device
US20100141818A1 (en) Solid state image pickup device and camera
WO2017018188A1 (fr) Capteur d'image et dispositif électronique
JP7310098B2 (ja) 赤外線検出器の制御回路及び制御方法、撮像装置
US20180098005A1 (en) Solid-state imaging device and electronic device
JP6740230B2 (ja) 固体撮像装置および電子機器
TWI720947B (zh) 用以增加像素靈敏度及動態範圍之方法及裝置
JPWO2017014070A1 (ja) 撮像素子、及び、電子機器
JP6954268B2 (ja) 固体撮像装置、信号処理方法、および電子機器
WO2018056051A1 (fr) Élément d'imagerie, procédé de fonctionnement d'élément d'imagerie, dispositif d'imagerie et dispositif électronique
US20230064794A1 (en) Photoelectric conversion device, image pickup apparatus, control method, and storage medium
JP4857996B2 (ja) 撮像装置
WO2022249554A1 (fr) Élément d'imagerie à semi-conducteurs et dispositif électronique
JP2017059898A (ja) 撮像素子、撮像装置、カメラ、車、およびモバイル端末
JP5737924B2 (ja) 撮像装置
US11563904B2 (en) Imaging apparatus and imaging control method
KR20250052766A (ko) 이미지 센싱 장치
JP2010154567A (ja) 固体撮像装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17852828

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17852828

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP