Light detection device and light detection system

Abstract

[Problem] To make it possible to reduce power consumption without reducing image quality. [Solution] This light detection device comprises: a pixel array unit that has a plurality of arrayed pixels, performs photoelectric conversion for each of the pixels by using supplied power supply voltage, and outputs analog pixel signals; an analog-to-digital converter that performs analog-to-digital conversion on the pixel signals, thereby generating digital pixel signals; a signal processing unit that performs signal processing on the digital pixel signals; a monitoring signal generation unit that generates a monitoring signal for monitoring the internal state of at least one among the pixel array unit, the analog-to-digital converter, and the signal processing unit; and an interface unit that transmits the monitoring signal to a power supply device that controls at least one of the voltage level or the operating frequency of the power supply voltage.

Description

Optical Detection Device and Optical Detection System

[0001] The present disclosure relates to an optical detection device and an optical detection system.

[0002] An information processing device has been proposed that performs image processing with low power consumption if there is no change in the image captured by an image sensor module (see Patent Document 1).

[0003] In addition, an integrated circuit device has been proposed that controls the power supply voltage according to the operating frequency and operating mode (see Patent Document 2).

[0004] Japanese Patent Application Laid-Open No. 2016-62148, Japanese Patent Application Laid-Open No. 2020-13859

[0005] Patent Document 1 discloses a power supply device and a PMIC (Power Management Integrated Circuit), but the drive control of the system only changes the drive state of the image sensor, such as the resolution and frame rate of the image sensor.

[0006] In addition, in Patent Document 2, the power supply voltage for the operating frequency and temperature is determined by referring to a previously prepared table.

[0007] As described above, both Patent Documents 1 and 2 control the supply voltage of the power supply device and the drive of the semiconductor integrated circuit without monitoring the detailed internal state of the semiconductor integrated circuit at the power supply destination, so there is still room for power reduction. In particular, when the power supply destination is an image sensor, image quality is of the utmost importance, and it is desired to achieve low power consumption without degrading the image quality.

[0008] Therefore, the present disclosure provides an optical detection device and an optical detection system that can achieve low power consumption without degrading the image quality by considering the internal state of the image sensor.

[0009] To solve the above problems, the present disclosure provides a photodetector comprising: a pixel array unit having a plurality of arranged pixels and performing photoelectric conversion for each pixel using a supplied power supply voltage to output an analog pixel signal; an analog-to-digital converter performing analog-to-digital conversion on the pixel signal to generate a digital pixel signal; a signal processing unit performing signal processing on the digital pixel signal; a monitor signal generation unit that generates a monitor signal to monitor the internal state of at least one of the pixel array unit, the analog-to-digital converter, and the signal processing unit; and an interface unit that transmits the monitor signal to a power supply device that controls at least one of the voltage level or operating frequency of the power supply voltage.

[0010] The monitor signal may include information for evaluating the image quality of the image data generated based on the digital pixel signal.

[0011] The monitor signal may include at least one piece of information regarding random noise, horizontal noise, vertical streak noise, or the number of white dots generated in the pixel array.

[0012] The pixel array portion includes: a plurality of pixels arranged in a first direction and a second direction; a plurality of first optical black pixels arranged at the end of a first pixel group including two or more pixels arranged in the first direction and which are shielded from light; a first optical black region including a plurality of the first optical black pixels arranged in the second direction; a plurality of second optical black pixels arranged at the end of a second pixel group including two or more pixels arranged in the second direction and which are shielded from light; and a second optical black region including a plurality of the second optical black pixels arranged in the first direction. The horizontal stripe noise may be calculated by averaging the pixel values ​​of the plurality of first optical black pixels included in the first optical black region, and the vertical stripe noise may be calculated by averaging the pixel values ​​of the plurality of second optical black pixels included in the second optical black region.

[0013] The monitor signal may also include a signal that includes the ratio of the horizontal noise to the vertical noise.

[0014] The signal processing unit may generate image data for each frame based on the digital pixel signals, and the monitor signal generation unit may generate the monitor signals for each frame.

[0015] The aforementioned monitoring signal may include information regarding the importance of each frame.

[0016] The signal processing unit generates image data for each frame based on the digital pixel signals, and the monitor signal may include information about parts of the image data that have different levels of importance.

[0017] The system includes a storage unit that stores information for evaluating the image quality of past frames, and the monitor signal generation unit may generate the monitor signal by taking into account the information stored in the storage unit.

[0018] The system comprises a temperature measuring unit that measures the temperature around at least one of the pixel array unit, the analog-to-digital converter, the signal processing unit, the monitor signal generation unit, and the interface unit, and the monitor signal may include temperature information measured by the temperature measuring unit.

[0019] The monitor signal may include information regarding the operating state of the pixel array.

[0020] The information relating to the operating state of the pixel array may include information identifying the shutter period, exposure period, analog pixel signal readout period, and vertical blanking period for each frame.

[0021] The pixel array section may be supplied with a power supply voltage from the power supply device during the shutter period and the readout period that has less noise and a higher operating frequency than during the exposure period and the vertical blanking period.

[0022] The system comprises the pixel array unit, the analog-to-digital converter, the signal processing unit, the monitor signal generation unit, the interface unit, and an internal power supply circuit that generates at least one of the internal voltage or internal current used in at least one of the interface units, wherein the monitor signal may include information on at least one of the internal voltage or internal current.

[0023] The system comprises the pixel array unit, the analog-to-digital converter, the signal processing unit, the monitor signal generation unit, the interface unit, and an internal power supply circuit that generates at least one of the internal voltage or internal current used in at least one of the interface units, and the internal power supply circuit may control at least one of the internal voltage or internal current based on the monitor signal.

[0024] The aforementioned monitor signal may include information about the timing at which noise should be reduced.

[0025] The timing for reducing the noise may include the shutter period for each frame in the pixel array, the readout period of the analog pixel signal, and the analog-to-digital conversion period.

[0026] According to this disclosure, a photodetection system is provided, comprising: a photodetector as described above; and a power supply unit that supplies the power supply voltage to the photodetector, wherein the power supply unit includes: a receiving unit that receives the monitor signal; and a power control unit that controls at least one of the voltage level or operating frequency of the power supply voltage supplied to the photodetector based on the received monitor signal.

[0027] The power supply unit may include: a first power supply unit that generates a first power supply voltage by variably controlling the operating frequency; a second power supply unit that generates a second power supply voltage which has lower power efficiency than the first power supply unit and less noise than the first power supply voltage; and a switching circuit that switches between the first power supply voltage and the second power supply voltage based on the monitor signal and supplies them to the photodetector.

[0028] The optical detection device may be connected to a peripheral device, the monitor signal generation unit may generate a monitor signal that includes information about the power supply voltage supplied to the peripheral device, and the power supply device may control the power supply voltage supplied to the peripheral device based on the monitor signal.

[0029] A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to the first embodiment. A diagram showing waveforms illustrating the relationship between the power supply voltage generated by the power supply unit and the power consumption of the photodetector, and waveforms illustrating the relationship between the power supply voltage generated by the power supply unit and the image quality of the photodetector. A diagram illustrating a method for detecting horizontal noise and vertical streak noise using the OPB region. A diagram showing the waveform of the power spectrum obtained by frequency conversion of horizontal noise. A diagram showing an example in which the acceptable upper limit of various noises differs for each operating mode. A diagram showing an example in which the acceptable limit of various noises differs for each group of internal setting parameters stored in the register. A diagram schematically showing that the importance of image data differs for each frame. A diagram showing an example in which high-importance and low-importance parts are mixed in the image data generated for each frame. A diagram showing the acceptable limit of various noises for high-importance frames or pixel areas, and the acceptable limit of various noises for low-importance frames or pixel areas. A timing diagram of the photodetector and power supply unit according to the first embodiment. A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to a first modification of the first embodiment. A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to a second modification of the first embodiment. A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to a third modification of the first embodiment. A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to a fourth modification of the first embodiment. A diagram showing the operating state of the photodetector according to the second embodiment. A diagram showing the operating state of the photodetector according to the third embodiment. A block diagram showing the schematic configuration of a photodetection system equipped with a photodetector according to the fourth embodiment. A block diagram showing an example of the schematic configuration of a vehicle control system. An explanatory diagram showing an example of the installation positions of the external information detection unit and the imaging unit.

[0030] Embodiments of the photodetector and photodetector system will be described below with reference to the drawings. While the main components of the photodetector and photodetector system will be described below, there may be components and functions not shown or described. The following description does not exclude any components or functions not shown or described.

[0031] (First Embodiment) Figure 1 is a block diagram showing the schematic configuration of a photodetection system 2 equipped with a photodetector 1 according to the first embodiment. As shown in Figure 1, the photodetection system 2 according to the first embodiment comprises a photodetector 1 and a power supply 3.

[0032] The light detection device 1 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The light detection device 1 may also be an image sensor that captures visible light, an image sensor that captures light wavelengths other than visible light (for example, near-infrared light), or an EVS (Event-Based Vision Sensor) that detects event information. The following explanation will mainly describe an example where the light detection device 1 is a CMOS image sensor that captures visible light.

[0033] The light detection device 1 comprises a pixel array unit 4, an analog-to-digital converter (hereinafter referred to as ADC) 5, a signal processing unit 6, a monitor signal generation unit 7, and an interface (IF) unit 8.

[0034] The pixel array unit 4 has a plurality of pixels arranged in a first direction x and a second direction y, and generates an analog pixel signal by performing photoelectric conversion for each pixel using the power supply voltage supplied from the power supply unit 3.

[0035] The ADC 5 generates a digital pixel signal by performing an analog-to-digital conversion on the pixel signal output from the pixel array unit 4. The signal processing unit 6 performs signal processing on the digital pixel signal.

[0036] The monitor signal generation unit 7 generates a monitor signal that monitors the internal state of at least one of the pixel array unit 4, the ADC 5, and the signal processing unit 6. The monitor signal includes, for example, information for evaluating the image quality of the image data generated based on the digital pixel signal. The monitor signal generation unit 7 generates a monitor signal for each frame, for example. Alternatively, the monitor signal generation unit 7 includes information about parts of the image data generated for each frame that have different levels of importance.

[0037] The interface unit 8 transmits a monitor signal to the power supply unit 3, which controls at least one of the voltage level and operating frequency of the power supply voltage of the light detection device 1. The interface unit 8 may also transmit the monitor signal to the power supply unit 3 using a general-purpose communication standard such as GPIO (General Purpose Input / Output) or I2C (Inter-Integrated Circuit).

[0038] The interface unit 8 may transmit and receive signals not only to the power supply unit 3 but also to the application processor (hereinafter referred to as AP) 10. Alternatively, a separate interface unit for AP 10 may be provided, distinct from the interface unit 8 for the power supply unit 3. AP 10 performs various signal processing on the image data generated by the light detection device 1. AP 10 also transmits control signals to the light detection device 1 via the interface unit 8.

[0039] The power supply unit 3 supplies the power supply voltage generated by the DC-DC converter (first power supply unit) 13 or the LDO regulator (second power supply unit) 14 to the photodetector 1. The DC-DC converter 13 generates a power supply voltage of a desired voltage level by switching the voltage from the main power supply 11 at a predetermined operating frequency. The DC-DC converter 13 has excellent power efficiency, but because it switches, the generated power supply voltage contains a lot of noise. In contrast, the LDO regulator 14 can generate a power supply voltage with less noise, but because it uses a resistive element to step down the voltage, it has poor power efficiency and generates a lot of heat.

[0040] The power supply device 3 includes a main power supply 11 and a power management IC (hereinafter, PMIC: Power Management Integrated Circuit) 12. The PMIC 12 includes a DC-DC converter 13, a LDO (Low Drop Out) regulator 14, a power supply control unit 15, a processing unit 16, and an interface unit 17.

[0041] The number of the DC-DC converter 13 and the LDO regulator 14 provided inside the PMIC 12 is arbitrary. The power supply control unit 15 controls the voltage level of the power supply voltage output from the DC-DC converter 13 and the LDO regulator 14 and the operating frequency of the DC-DC converter 13.

[0042] The monitor signal from the light detection device 1 is received by the interface unit 17 in the power supply device 3 and processed by the processing unit 16. The PMIC 12 controls the DC-DC converter 13 and the LDO regulator 14 based on the monitor signal. The DC-DC converter 13 controls the operating frequency based on the monitor signal and variably controls the voltage level of the power supply voltage. The LDO regulator 14 generates a power supply voltage with less noise using the power supply voltage from the DC-DC converter 13.

[0043] As described above, the DC-DC converter 13 and the LDO regulator 14 included in the power supply device 3 have advantages and disadvantages. The light detection system 2 according to the first embodiment supplies the power supply voltage generated by the LDO regulator 14 to the light detection device 1.

[0044] FIG. 2 is a diagram showing a waveform w1 indicating the relationship between the power supply voltage generated by the power supply device 3 and the power consumption of the light detection device 1, and a waveform w2 indicating the relationship between the power supply voltage generated by the power supply device 3 and the image quality of the light detection device 1.

[0045] As shown in the waveform w1, as the power supply voltage decreases, the power consumption decreases almost linearly. Also, as shown in the waveform w2, when the power supply voltage is within a predetermined voltage range, the image quality is constant, and when the power supply voltage drops below the predetermined voltage range, noise increases and the image quality deteriorates.

[0046] From the waveforms w1 and w2 in FIG. 2, it can be seen that it is possible to reduce the power supply voltage without affecting the image quality. Also, when the image quality is not a problem, the power supply voltage can be further reduced.

[0047] The light detection device 1 according to the first embodiment is characterized by reducing power consumption without affecting the image quality of the captured image. The reduction of power consumption can be achieved by lowering the voltage level of the power supply voltage supplied from the power supply device 3 to the light detection device 1. Also, the operating frequency of the power supply device 3 affects the image quality of the captured image generated by the light detection device 1.

[0048] The light detection device 1 according to the first embodiment transmits the monitor signal generated by the monitor signal generation unit 7 to the power supply device 3. The monitor signal includes information on noise generated in the pixel array unit 4, information on the operation mode of the light detection device 1, or information on the internal setting parameter group of the light detection device 1. The power supply device 3 controls the voltage level of the power supply voltage supplied to the light detection device 1 based on the monitor signal from the light detection device 1. Also, the power supply device 3 controls at least one of the voltage level or the operating frequency of the power supply voltage based on the information included in the monitor signal.

[0049] Various information can be included in the monitor signal transmitted from the light detection device 1 to the power supply device 3. Hereinafter, some typical specific examples of the information included in the monitor signal will be described.

[0050] (First example of monitor signal) The image quality deteriorates due to noise included in the captured image. The noise included in the captured image includes random noise, horizontal streaking noise, vertical stripe noise, the number of white dots, and the like.

[0051] Optical black areas (hereinafter referred to as OPB areas) are provided at the row and column ends of the pixel array section 4 of the light detection device 1. The OPB areas are pixel areas that are shielded from light by a metal film or the like, and are provided around the effective pixel area. The OPB areas are provided with a group of pixels having the same pixel structure as the pixel group of the effective pixel area. Each pixel in the OPB area detects the dark current when no light is incident on it. Therefore, by using the OPB areas, random noise, horizontal noise, vertical streak noise, and the number of white dots can be detected. Since white dots can occur randomly at any pixel in the pixel array section 4, the number of white dots in the effective pixel area can be estimated by counting the number of white dots in the OPB areas. Similarly, by comparing the pixel values ​​of each pixel in the OPB areas, the presence or absence of random noise at each pixel can be measured. Since random noise can occur randomly in any pixel of the pixel array 4, the frequency of random noise in the effective pixel area of ​​the pixel array 4 can be estimated from the frequency of random noise in the OPB area.

[0052] Figure 3 illustrates a method for detecting horizontal and vertical streak noise using the OPB region 21. Below, we will describe an example in which the first OPB region 21a is located at the row-direction end of the pixel array 4, and the second OPB region 21b is located at the column-direction end.

[0053] In the first OPB region 21a, multiple OPB pixels 22 are provided for each pixel row. The average value of the pixel values ​​of the multiple OPB pixels 22 for each pixel row is calculated, and from the multiple average values ​​in the column direction, the horizontal stripping noise waveform w3 shown in Figure 3 is obtained. From this horizontal stripping noise waveform w3, the horizontal stripping noise σrow is calculated.

[0054] Similarly, in the second OPB region 21b, multiple OPB pixels 22 are provided for each pixel row. The average value of the multiple OPB pixels 22 for each pixel row is calculated, and the vertical streak noise waveform w4 shown in Figure 3 is obtained from the multiple average values ​​in the row direction. The vertical streak noise σcolumn is calculated from this vertical streak noise waveform w4.

[0055] Figure 4 shows the waveform w5 of the power spectrum obtained by frequency conversion of the horizontal noise σrow. In Figure 4, the horizontal axis is frequency [Hz] and the vertical axis is signal strength [W]. From the power spectrum of the horizontal noise σrow, a specific frequency that is causing the horizontal noise can be detected. Since this specific frequency is highly likely to be the operating frequency of the power supply unit 3, the horizontal noise σrow can be reduced by instructing the power supply unit 3 to switch its operating frequency.

[0056] Furthermore, the vertical streak noise σcolumn can also be reduced by analyzing the power spectrum using the same method as in Figure 4, thereby instructing the power supply unit 3 to switch its operating frequency.

[0057] The monitor signal generation unit 7 transmits a monitor signal to the power supply unit 3 that includes information such as random noise, horizontal noise, vertical streak noise, and the number of white dots, calculated using the OPB region 21. The power supply unit 3 controls the operating frequency, for example, based on the monitor signal from the photodetector 1. The power supply unit 3 may also control the voltage level of the power supply voltage based on the monitor signal.

[0058] Thus, the monitor signal generation unit 7 may transmit a monitor signal containing information about various types of noise to the power supply unit 3.

[0059] (Second example of monitor signal) The light detection device 1 according to the first embodiment may have a function to perform imaging by switching between multiple operating modes. In this case, it is assumed that the degree of noise generation will differ for each operating mode. An operating mode is, for example, a mode that generates a high-resolution image by performing imaging with all pixels, or a mode that generates a low-resolution image by performing imaging with some pixels downsampled.

[0060] Figure 5 shows an example where the acceptable upper limits for various types of noise differ depending on the operating mode. Figure 5 lists the acceptable upper limits for random noise σrn, the number of white dots, horizontal noise σrow, vertical streak noise σcolumn, the ratio of horizontal noise to vertical streak noise σrow / σcolumn, and the power spectrum of vertical streak noise. In addition, the acceptable lower limit for the vertical streak noise ratio σrow / σcolumn is also listed. The upper and lower limits listed in Figure 5 are just examples. Hereafter, the upper and lower limits will be collectively referred to as limit values.

[0061] As shown in Figure 5, the degree of noise generation changes depending on the operating mode, so it is desirable to switch at least one of the voltage level of the power supply voltage supplied from the power supply unit 3 to the photodetector 1 and the operating frequency for each operating mode.

[0062] Thus, the monitor signal generation unit 7 may transmit a monitor signal to the power supply unit 3 that includes information regarding the operating mode of the photodetector 1. For example, the monitor signal may include the ratio of lateral noise to vertical noise.

[0063] (Third example of monitor signal) The light detection device 1 according to the first embodiment may have a function to perform imaging by switching various parameters. The light detection device 1 has various parameters such as frame rate, horizontal line length, internal frequency, and gain setting. For example, the setting values ​​of various parameters differ depending on the size or resolution of the pixel area to be imaged, the frame rate, etc. Also, the setting values ​​of various parameters differ for each operating mode. Since the setting of parameters is complex, values ​​of an internal setting parameter group including multiple parameters to be set all at once may be stored in each of multiple registers, and the multiple parameters stored in the register corresponding to the selected internal setting parameter group may be set.

[0064] Figure 6 shows an example where the acceptable limits for various types of noise differ depending on the set of internal setting parameters stored in the registers. Figure 6 lists the same types of noise limits as in Figure 5. The set of internal setting parameters is stored in the corresponding registers. Since the degree of occurrence of multiple types of noise differs for each set of internal setting parameters, the acceptable limits also change.

[0065] As shown in Figure 6, the degree of noise generation and the acceptable noise limit change depending on the internal setting parameter group, which consists of various combinations of parameters such as frame rate, horizontal line length, internal frequency, and gain setting. Therefore, it is desirable to switch at least one of the voltage level of the power supply voltage supplied from the power supply unit 3 to the photodetector 1 and the operating frequency, depending on the selection of the internal setting parameter group.

[0066] Thus, the monitor signal generation unit 7 may transmit a monitor signal to the power supply unit 3 that includes information regarding the internal setting parameters of the light detection device 1.

[0067] (Fourth example of a monitor signal) The light detection device 1 generates image data for each frame based on the pixel signal generated by the photoelectric conversion of each pixel. The importance of the image data for each frame is not necessarily the same, and the importance of the image data may differ from frame to frame.

[0068] Figure 7 schematically illustrates that the importance of image data differs from frame to frame. The example in Figure 7 shows that the image data of the third frame, fr3, is more important than the image data of the other frames, fr1, fr2, and fr4.

[0069] Figure 8 shows an example where the image data generated for each frame contains a mixture of high-importance parts (IM1) and low-importance parts (IM2). For example, in the image data, the background area is more important than the area containing the subject.

[0070] The light detection device 1 needs to switch, for example, a group of internal setting parameters depending on their importance. As shown in Figure 6, switching the group of internal setting parameters increases or decreases the noise in the image data, which affects the image quality.

[0071] Figure 9 shows the acceptable limits for various types of noise in high-priority frames or pixel regions, and the acceptable limits for various types of noise in low-priority frames or pixel regions. As shown in Figure 9, the noise limits are set more strictly in high-priority frames or pixel regions than in low-priority frames or pixel regions.

[0072] Thus, the monitor signal generation unit 7 may generate a monitor signal that includes information about frames or pixel regions of high (or low) importance.

[0073] (Timing diagram of the light detection device 1) Figure 10 is a timing diagram of the light detection device 1 and power supply device 3 according to the first embodiment. Figure 10 shows the operating state of the pixel array unit 4, the signal waveform transmitted from the light detection device 1 to AP 10, the waveform of a monitor signal including information on the power supply voltage of each part of the light detection device 1 other than the interface unit 8 (hereinafter referred to as analog / digital power supply voltage), the waveform of a monitor signal including information on the power supply voltage of the interface unit 8 (hereinafter referred to as IF power supply voltage), the switching timing of the operating frequency of the analog / digital power supply voltage, the switching timing of the operating frequency of the IF power supply voltage, the voltage waveform of the analog / digital power supply voltage, and the voltage waveform of the IF power supply voltage.

[0074] The pixel array unit 4 sequentially repeats the operating states of the shutter period (time t1 to t2), exposure period (time t2 to t3), pixel signal readout period (time t3 to t4), and vertical blanking period (time t4 to t5).

[0075] During the pixel signal readout period (times t3 to t4), the digital pixel signal is transmitted to AP10. The photodetector 1 has limited locations requiring power supply voltage during the exposure period and the vertical blanking period. For example, during the exposure period, the power supply to the pixel transistors other than the transfer transistor and ADC5 can be stopped. Also, during the vertical blanking period, the power supply to the pixel circuit, not just ADC5, can be stopped. Furthermore, the photodetector 1 can stop the power supply to the interface unit 8 except during the signal transmission period to AP10 (times t3 to t4).

[0076] Therefore, the light detection device 1 notifies the power supply device 3 via a monitor signal of the timing when it is necessary to supply and stop the power voltage of each part within the light detection device 1.

[0077] The PMIC 12 in the power supply unit 3 controls the operating frequency of the DCDC converter 13 based on the monitor signal from the photodetector 1. During the shutter period of the pixel array section 4 in the photodetector 1 and the pixel signal readout period, the PMIC 12 increases the operating frequency of the DCDC converter 13 and supplies a high voltage level power supply voltage to the photodetector 1. During other periods, it lowers the operating frequency and supplies a low voltage level power supply voltage to the photodetector 1.

[0078] More specifically, the PMIC 12 supplies the photodetector 1 with either a constant power supply voltage (dashed line in Figure 10) or a power supply voltage with a variable voltage level based on a monitor signal (solid line in Figure 10). When the power supply voltage is variable, for example, the voltage level is increased during the shutter period and the pixel signal readout period, and decreased during other periods. The PMIC 12 can also switch between supplying a constant or variable power supply voltage to the interface unit 8. When it is variable, the voltage level is increased during the period when the photodetector 1 transmits the pixel signal to AP 10, and decreased at other times.

[0079] (First Modification of the First Embodiment) Figure 11 is a block diagram showing the schematic configuration of a photodetection system 2 equipped with a photodetection device 1a according to the first modification of the first embodiment. In Figure 11, components common to Figure 1 are denoted by the same reference numerals, and the differences will be explained below.

[0080] The first modified photodetector 1a shown in Figure 11 includes a storage unit 18 in addition to the configuration of the photodetector 1 in Figure 1. The storage unit 18 stores information for evaluating the image quality of past frames. More specifically, the storage unit 18 stores the pixel signals of the OPB region 21 provided in the pixel array 4 in at least the most recent frame.

[0081] As described above, the OPB region 21 (the first OPB region 21a and the second OPB region 21b in Figure 3) has a plurality of OPB pixels 22 arranged in a first direction (row direction) or a second direction (column direction). The number of OPB pixels 22 in the OPB region 21 is not necessarily constant, and in cases where it is necessary to miniaturize the pixel array section 4, the number of OPB pixels 22 in the OPB region 21 must be reduced. As explained in Figure 3, horizontal noise and vertical streak noise are calculated by averaging the pixel values ​​of the plurality of OPB pixels 22 in the OPB region 21. Therefore, if there are not enough OPB pixels 22 in the OPB region 21, it becomes impossible to calculate horizontal noise and vertical streak noise accurately.

[0082] Therefore, if the memory unit 18 can store the pixel values ​​of each OPB pixel 22 in the OPB region 21 of past frames (at least the most recent frame), these pixel values ​​can be read out and used together with the pixel values ​​of each OPB pixel 22 in the current frame for averaging calculations, thereby improving the calculation accuracy of horizontal noise and vertical streak noise.

[0083] Furthermore, the pixel values ​​of each OPB pixel 22 in the OPB region 21 of past frames stored in the memory unit 18 can also be used to estimate the number of random noises and white dots.

[0084] (Second Modification of the First Embodiment) Figure 12 is a block diagram showing the schematic configuration of a photodetection system 2 equipped with a photodetection device 1b according to a second modification of the first embodiment. In Figure 12, components common to Figure 1 are denoted by the same reference numerals, and the differences will be explained below.

[0085] The photodetector 1b according to the second modified example shown in Figure 12 has an internal power supply circuit 23 in addition to the configuration of the photodetector 1 in Figure 1. The internal power supply circuit 23 uses the power supply voltage supplied from the power supply device 3 to generate an internal voltage or internal current at a voltage level different from the power supply voltage.

[0086] The internal power supply circuit 23 includes, for example, a charge pump (CP) 24 and an LDO regulator 25. The charge pump 24 is used to boost the power supply voltage. The LDO regulator 25 generates the internal voltage from the boosted voltage generated by the charge pump 24.

[0087] At least one of the internal voltage or internal current generated by the internal power supply circuit 23 can be used in any circuit within the photodetector circuit.

[0088] The light detection device 1 in Figure 12 may also include an internal power supply monitoring circuit 26 and a thermometer (temperature measurement unit) 27, in addition to the internal power supply circuit 23.

[0089] The internal power supply monitoring circuit 26 monitors at least one of the internal voltage or internal current generated by the internal power supply circuit 23 and sends at least one of the monitored internal voltage or internal current to the monitoring signal generation unit 7.

[0090] The monitor signal generation unit 7 generates a monitor signal that includes information about at least one of the internal voltage or internal current monitored by the internal power supply monitor circuit 26.

[0091] The thermometer 27 is placed at any location inside the photodetector 1. The temperature information measured by the thermometer 27 is sent to the monitor signal generation unit 7. The monitor signal generation unit 7 generates a monitor signal that includes the temperature information measured by the thermometer 27.

[0092] In this way, by generating a monitor signal that includes at least one of the internal voltage or internal current and at least one of the temperature information and transmitting it from the photodetector 1 to the power supply unit 3, the power supply unit 3 can control at least one of the voltage level or operating frequency of the power supply voltage supplied to the photodetector 1, taking into account at least one of the internal voltage, internal current, and temperature of the photodetector 1.

[0093] (Third Modification of the First Embodiment) Figure 13 is a block diagram showing the schematic configuration of a photodetection system 2 equipped with a photodetector 1c according to the third modification of the first embodiment. In Figure 13, components common to Figure 12 are denoted by the same reference numerals, and the differences will be explained below.

[0094] The photodetector 1c according to the third modified example shown in Figure 13 has the same or similar block configuration as that in Figure 12. In the photodetector 1c according to the third modified example, the monitor signal generated by the monitor signal generation unit 7 is not only transmitted to the power supply unit 3, but is also used to control the internal power supply circuit 23 within the photodetector 1.

[0095] As a result, the internal power supply circuit 23 can variably control its operating frequency, control the voltage level of the internal voltage, and control the amount of internal current based on the monitor signal. The power supply device 3 also controls at least one of the voltage level of the power supply voltage or the operating frequency based on the monitor signal. The photodetector device 1 in Figure 13 is provided with a PLL circuit 28 that controls the operating frequency of the internal power supply circuit 23.

[0096] (Fourth Modification of the First Embodiment) Figure 14 is a block diagram showing the schematic configuration of a photodetection system 2 equipped with a photodetector 1d according to the fourth modification of the first embodiment. In Figure 14, components common to Figure 13 are denoted by the same reference numerals, and the differences will be explained below.

[0097] The photodetection system 2 according to the fourth modified example shown in Figure 14 has a different internal configuration of the power supply unit 3 than the power supply unit 3 in Figure 13. The power supply unit 3 according to the fourth modified example includes a switching circuit 29 that switches between supplying the power supply voltage generated by the DC-DC converter 13 in the PMIC 12 or the power supply voltage generated by the LDO regulator 14 to the photodetection device 1.

[0098] As mentioned above, the DC-DC converter 13 generates a power supply voltage with excellent power efficiency, but it has the disadvantage of containing a lot of noise in the power supply voltage. The LDO regulator 14 generates the power supply voltage using a resistor, so it has less noise, but it has the disadvantage of high power loss and poor power efficiency.

[0099] The power supply device 3 according to the fourth modified example generates a power supply voltage by switching the DC-DC converter 13 or the LDO regulator 14 by switching the switching circuit 29 based on a monitor signal from the photodetector 1. For example, during the shutter period of the pixel array section 4 and the pixel signal readout period, the power supply voltage generated by the DC-DC converter 13 may be supplied to the photodetector 1, and during other periods, the power supply voltage generated by the LDO regulator 14 may be supplied to the photodetector 1.

[0100] Thus, in the first embodiment, a monitor signal containing information about the internal state of the photodetectors 1 to 1d is transmitted from the photodetectors 1 to 1d to the power supply unit 3. Based on the monitor signal, the power supply unit 3 can vary the voltage level of the power supply voltage or vary the operating frequency according to the internal state of the photodetectors 1 to 1d. This reduces the power consumption of the photodetectors 1 to 1d.

[0101] (Second Embodiment) The first embodiment mainly described an example of controlling the power supply voltage in order to drive the photodetector 1 with low power consumption while maintaining image quality, but the second embodiment controls the power supply voltage according to the operating state of the photodetector 1.

[0102] The photodetector 1d according to the second embodiment has a block configuration similar to that shown in Figure 14, for example. The monitor signal generation unit 7 generates a monitor signal that includes information about the operating state of the photodetector 1 based on the operating state of the pixel array unit 4 and at least one of the internal voltage or internal current generated by the internal power supply circuit 23.

[0103] Figure 15 shows the operating state of the photodetector 1d according to the second embodiment. Similar to Figure 10, the photodetector 1d according to the second embodiment repeats the shutter period, exposure period, pixel signal readout period, and vertical blanking period in sequence, but a deep sleep period is provided as part of the vertical blanking period. Figure 15 shows the pixel signal readout period (t11-t12), vertical blanking period (t12-t13), deep sleep period (t13-t14), vertical blanking period (t14-t15), shutter period (t15-t16), and exposure period (t16-t17). Also, Figure 15 shows the waveform of the current consumption of the photodetector 1d according to the second embodiment, the waveform of the internal voltage of the photodetector 1, and the waveform of the power supply voltage output from the power supply unit 3. The dashed waveform in Figure 15 is the voltage waveform when the power supply unit 3 does not control the power supply voltage during deep sleep. As shown by the dashed waveform, if the power supply voltage is not controlled during deep sleep, the internal voltage of the photodetector 1 rises higher than during the vertical blanking period, resulting in increased power consumption.

[0104] On the other hand, if the power supply unit 3 lowers the voltage level of the power supply voltage during the deep sleep period based on the monitor signal, the voltage level of the internal voltage of the photodetector 1 can be lowered, thereby reducing the power consumption of the photodetector 1.

[0105] The monitor signal generation unit 7 generates a monitor signal that includes information identifying, for example, the shutter period, exposure period, analog pixel signal readout period, and vertical blanking period for each frame. Based on the monitor signal from the photodetector 1d, the power supply unit 3 supplies the photodetector 1d a power supply voltage with less noise and a higher operating frequency than the exposure period and vertical blanking period, for example, during the shutter period and readout period.

[0106] Thus, in the second embodiment, by including information regarding the operating state of the photodetector 1 in the monitor signal, the power supply unit 3 can supply the photodetector 1 with a power supply voltage level corresponding to the operating state of the photodetector 1. Therefore, since the photodetector 1 is not performing any effective operation during the deep sleep period within the vertical blanking period, power consumption can be reduced without interfering with the operation of the photodetector 1 by lowering the voltage level of the power supply voltage supplied to the photodetector 1.

[0107] (Third Embodiment) The photodetector 1 according to the third embodiment has a block configuration similar to any of the photodetector 1 described in the first embodiment.

[0108] In the third embodiment of the light detection device 1, the monitor signal generation unit 7 generates a monitor signal that includes information about the timing at which noise should be reduced. Thus, the third embodiment is characterized by explicitly notifying the power supply device 3 of the timing at which noise should be reduced.

[0109] Figure 16 shows the operating state of the light detection device 1 according to the third embodiment. Figure 16 illustrates the shutter period (times t21 to t22), the exposure period (times t22 to t23), the pixel signal readout period (times t23 to t24), and the vertical blanking period (times t24 to t25). Figure 16 also illustrates the shutter and pixel signal readout sequence, the monitor signal, and the noise included in the power supply voltage. Furthermore, on the right side of Figure 16, an enlarged timing diagram of a portion of the pixel signal readout period (times t23a to t23b) is shown.

[0110] Since it is desirable for the noise contained in the power supply voltage supplied from the power supply unit 3 to be as low as possible during the shutter period and the pixel signal readout period, the monitor signal sent to the power supply unit 3 during the shutter period and the pixel signal readout period includes a pulse signal that indicates the timing when noise should be reduced, which is sent periodically and repeatedly.

[0111] On the other hand, during the exposure period and the vertical blanking period, even if the noise contained in the power supply voltage supplied from the power supply unit 3 increases, the operation of the photodetector 1 will not be affected. Therefore, during these periods, the monitor signal is fixed at a low level, for example.

[0112] Thus, in the third embodiment, by transmitting a monitor signal containing information about the timing at which noise should be reduced from the photodetector 1 to the power supply unit 3, the timing at which noise should be reduced can be explicitly notified from the photodetector 1 to the power supply unit 3. Therefore, the power supply unit 3 can supply a low-noise power supply voltage to the photodetector 1 at the timing at which noise should be reduced.

[0113] (Fourth Embodiment) The photodetector 1e according to the fourth embodiment is characterized by generating a monitor signal that includes information on the power supply voltage to be supplied to the peripheral equipment of the photodetector 1.

[0114] Figure 17 is a block diagram showing a schematic configuration of a photodetection system 2 equipped with a photodetector 1e according to the fourth embodiment. The photodetection system 2 according to the fourth embodiment has a configuration in which peripheral equipment 30 is added to the block configuration of Figure 14, for example.

[0115] The peripheral device 30 is a device used together with the light detection device 1, and can include, for example, an optical system placed on the light incident side of the light detection device 1, a light source that illuminates the area around the light detection device 1, and various other devices.

[0116] The optical system includes actuators such as a focusing mechanism or a zoom lens mechanism, and it is necessary to supply power voltage to these actuators from the power supply unit 3. Similarly, the light source also supplies current to its light-emitting elements based on the power voltage from the power supply unit 3.

[0117] The peripheral device 30 operates in accordance with the operation of the photodetector 1. For this reason, the monitor signal generation unit 7 generates a monitor signal that includes information about the power supply voltage supplied to the peripheral device 30. The power supply unit 3 reduces the power consumption of the peripheral device 30 by supplying the power supply voltage to the peripheral device 30 in accordance with the operation of the photodetector 1 based on the monitor signal from the photodetector 1.

[0118] <Examples of application to mobile devices> The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0119] Figure 18 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0120] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 18, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0121] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0122] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0123] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0124] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0125] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0126] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0127] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0128] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0129] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 18, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0130] Figure 19 shows an example of the installation position of the imaging unit 12031.

[0131] In Figure 19, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0132] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0133] Figure 19 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0134] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0135] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0136] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0137] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0138] The above describes an example of a vehicle control system to which the technology described herein may be applied. The technology described herein may be applied to the imaging unit 12031, etc., among the configurations described above.

[0139] Furthermore, this technology can take the following configurations: (1) A light detection device comprising: a pixel array unit having a plurality of arranged pixels and performing photoelectric conversion for each pixel using a supplied power supply voltage to output an analog pixel signal; an analog-to-digital converter performing analog-to-digital conversion on the pixel signal to generate a digital pixel signal; a signal processing unit performing signal processing on the digital pixel signal; a monitor signal generation unit that generates a monitor signal to monitor the internal state of at least one of the pixel array unit, the analog-to-digital converter, and the signal processing unit; and an interface unit that transmits the monitor signal to a power supply device that controls at least one of the voltage level or operating frequency of the power supply voltage. (2) The light detection device according to (1), wherein the monitor signal includes information for evaluating the image quality of image data generated based on the digital pixel signal. (3) The light detection device according to (2), wherein the monitor signal includes information on at least one of random noise, horizontal noise, vertical streak noise, or the number of white dots generated in the pixel array unit. (4) The light detection device according to (3), wherein the pixel array portion comprises: a plurality of pixels arranged in a first direction and a second direction; a plurality of first optical black pixels arranged at the end of a first pixel group including two or more pixels arranged in the first direction and shielded from light; a first optical black region including a plurality of the first optical black pixels arranged in the second direction; a plurality of second optical black pixels arranged at the end of a second pixel group including two or more pixels arranged in the second direction and shielded from light; and a second optical black region including a plurality of the second optical black pixels arranged in the first direction, wherein the horizontal drag noise is calculated by the average of the pixel values ​​of the plurality of first optical black pixels included in the first optical black region, and the vertical streak noise is calculated by the average of the pixel values ​​of the plurality of second optical black pixels included in the second optical black region. (5) The light detection device according to (3) or (4), wherein the monitor signal is a signal including the ratio of the horizontal drag noise to the vertical streak noise.(6) The light detection device according to any one of (1) to (5), wherein the signal processing unit generates image data for each frame based on the digital pixel signals, and the monitor signal generation unit generates the monitor signal for each frame. (7) The light detection device according to (6), wherein the monitor signal includes information regarding the importance of each frame. (8) The light detection device according to any one of (1) to (5), wherein the signal processing unit generates image data for each frame based on the digital pixel signals, and the monitor signal includes information regarding parts of the image data that have different importance. (9) The light detection device according to any one of (1) to (8), further comprising a storage unit that stores information for evaluating the image quality of past frames, and the monitor signal generation unit generates the monitor signal taking into account the information stored in the storage unit. (10) The photodetector according to any one of (1) to (9), comprising a temperature measuring unit for measuring the temperature around at least one of the pixel array unit, the analog-to-digital converter, the signal processing unit, the monitor signal generation unit, and the interface unit, wherein the monitor signal includes information on the temperature measured by the temperature measuring unit. (11) The photodetector according to any one of (1) to (10), wherein the monitor signal includes information on the operating state of the pixel array unit. (12) The photodetector according to (11), wherein the information on the operating state of the pixel array unit includes information identifying the shutter period, exposure period, analog pixel signal readout period, and vertical blanking period for each frame. (13) The photodetector according to (12), wherein the pixel array unit is supplied with a power supply voltage from the power supply device during the shutter period and the readout period that has less noise and a higher operating frequency than during the exposure period and the vertical blanking period.(14) The photodetector according to any one of (11) to (13), comprising a pixel array unit, an analog-to-digital converter, a signal processing unit, a monitor signal generation unit, an interface unit, and an internal power supply circuit that generates at least one of the internal voltages or internal currents used in at least one of the interface units, wherein the monitor signal includes information on at least one of the internal voltages or internal currents. (15) The photodetector according to any one of (11) to (13), comprising a pixel array unit, an analog-to-digital converter, a signal processing unit, a monitor signal generation unit, an interface unit, and an internal power supply circuit that generates at least one of the internal voltages or internal currents used in at least one of the interface units, wherein the internal power supply circuit controls at least one of the internal voltages or internal currents based on the monitor signal. (16) The photodetector according to any one of (1) to (15), wherein the monitor signal includes information on the timing at which noise should be reduced. (17) The photodetector according to (16), wherein the timing for reducing the noise includes the shutter period for each frame in the pixel array and the reading period of the analog pixel signal and the analog-to-digital conversion period. (18) A photodetector according to any one of (1) to (17), and a power supply unit that supplies the power supply voltage to the photodetector, wherein the power supply unit comprises a receiving unit that receives the monitor signal and a power control unit that controls at least one of the voltage level or operating frequency of the power supply voltage supplied to the photodetector based on the received monitor signal. (19) The photodetector according to (18), wherein the power supply unit comprises a first power supply unit that generates a first power supply voltage by variably controlling the operating frequency, a second power supply unit that generates a second power supply voltage which is less power efficient than the first power supply unit and has less noise than the first power supply voltage, and a switching circuit that switches between the first power supply voltage and the second power supply voltage and supplies them to the photodetector based on the monitor signal.(20) The light detection system according to (19), comprising a peripheral device connected to the light detection device, wherein the monitor signal generation unit generates the monitor signal including information about the power supply voltage supplied to the peripheral device, and the power supply device controls the power supply voltage supplied to the peripheral device based on the monitor signal.

[0140] The aspects of this disclosure are not limited to the individual embodiments described above, but include various modifications that a person skilled in the art could conceive, and the effects of this disclosure are not limited to those described above. In other words, various additions, modifications, and partial deletions are possible, as long as they do not depart from the conceptual idea and spirit of this disclosure derived from the claims and their equivalents.

[0141] 1, 1a, 1b, 1c, 1d, 1e: Light detection device, 2: Light detection system, 3: Power supply unit, 4: Pixel array unit, 6: Signal processing unit, 7: Monitor signal generation unit, 8: Interface unit, 10: Application processor (AP), 11: Main power supply, 13: DC-DC converter, 14: LDO regulator, 15: Power control unit, 16: Processing unit, 17: Interface unit, 18: Memory unit, 21: OPB area, 21a: First OPB area, 21b: Second OPB area, 22: OPB pixel, 23: Internal power supply circuit, 24: Charge pump, 25: LDO regulator, 26: Internal power supply monitor circuit, 27: Thermometer, 28: PLL circuit, 29: Switching circuit, 30: Peripheral devices

Claims

1. A light detection device comprising: a pixel array unit having a plurality of arranged pixels and performing photoelectric conversion on each pixel using a supplied power supply voltage to output an analog pixel signal; an analog-to-digital converter performing analog-to-digital conversion on the pixel signal to generate a digital pixel signal; a signal processing unit performing signal processing on the digital pixel signal; a monitor signal generation unit that generates a monitor signal to monitor the internal state of at least one of the pixel array unit, the analog-to-digital converter, and the signal processing unit; and an interface unit that transmits the monitor signal to a power supply device that controls at least one of the voltage level or operating frequency of the power supply voltage.

2. The light detection device according to claim 1, wherein the monitor signal includes information for evaluating the image quality of image data generated based on the digital pixel signal.

3. The light detection device according to claim 2, wherein the monitor signal includes at least one piece of information: random noise, horizontal noise, vertical streak noise, or the number of white dots generated in the pixel array.

4. The photodetector according to claim 3, wherein the pixel array portion comprises: a plurality of pixels arranged in a first direction and a second direction; a plurality of light-shielded first optical black pixels arranged at the end of a first pixel group including two or more pixels arranged in the first direction; a first optical black region including a plurality of the first optical black pixels arranged in the second direction; a plurality of light-shielded second optical black pixels arranged at the end of a second pixel group including two or more pixels arranged in the second direction; and a second optical black region including a plurality of the second optical black pixels arranged in the first direction, wherein the horizontal drag noise is calculated by the average of the pixel values ​​of the plurality of first optical black pixels included in the first optical black region; and the vertical drag noise is calculated by the average of the pixel values ​​of the plurality of second optical black pixels included in the second optical black region.

5. The optical detection device according to claim 3, wherein the monitoring signal is a signal that includes the ratio of the horizontal noise to the vertical noise.

6. The light detection device according to claim 1, wherein the signal processing unit generates image data for each frame based on the digital pixel signals, and the monitor signal generation unit generates the monitor signals for each frame.

7. The optical detection device according to claim 6, wherein the monitor signal includes information regarding the importance of each frame.

8. The light detection device according to claim 1, wherein the signal processing unit generates image data for each frame based on the digital pixel signal, and the monitor signal includes information about parts of the image data that are of different importance.

9. The light detection device according to claim 1, comprising a storage unit for storing information for evaluating the image quality of past frames, wherein the monitor signal generation unit generates the monitor signal taking into account the information stored in the storage unit.

10. The photodetector according to claim 1, comprising a temperature measuring unit for measuring the temperature around at least one of the pixel array unit, the analog-to-digital converter, the signal processing unit, the monitor signal generation unit, and the interface unit, wherein the monitor signal includes temperature information measured by the temperature measuring unit.

11. The light detection device according to claim 1, wherein the monitor signal includes information relating to the operating state of the pixel array.

12. The photodetector according to claim 11, wherein the information relating to the operating state of the pixel array includes information identifying the shutter period, exposure period, analog pixel signal readout period, and vertical blanking period for each frame.

13. The photodetector according to claim 12, wherein the pixel array is supplied with a power supply voltage from the power supply device during the shutter period and the readout period that has less noise and a higher operating frequency than during the exposure period and the vertical blanking period.

14. The photodetector according to claim 11, comprising: a pixel array unit; an analog-to-digital converter; a signal processing unit; a monitor signal generation unit; an interface unit; and an internal power supply circuit that generates at least one of the internal voltages or internal currents used in at least one of the interface units, wherein the monitor signal includes information on at least one of the internal voltages or internal currents.

15. The photodetector according to claim 11, comprising: a pixel array unit, an analog-to-digital converter, a signal processing unit, a monitor signal generation unit, an interface unit, and an internal power supply circuit that generates at least one of an internal voltage or internal current used in at least one of the interface units, wherein the internal power supply circuit controls at least one of the internal voltage or internal current based on the monitor signal.

16. The optical detection device according to claim 1, wherein the monitor signal includes information on the timing at which noise should be reduced.

17. The photodetector according to claim 16, wherein the timing for reducing the noise includes the shutter period for each frame in the pixel array, the readout period of the analog pixel signal, and the analog-to-digital conversion period.

18. A photodetection system comprising: a photodetector according to any one of claims 1 to 17; and a power supply device that supplies the power supply voltage to the photodetector, wherein the power supply device comprises: a receiving unit that receives the monitor signal; and a power control unit that controls at least one of the voltage level or operating frequency of the power supply voltage supplied to the photodetector based on the received monitor signal.

19. The photodetection system according to claim 18, wherein the power supply unit comprises: a first power supply unit that generates a first power supply voltage by variably controlling the operating frequency; a second power supply unit that generates a second power supply voltage which has lower power efficiency than the first power supply unit and less noise than the first power supply voltage; and a switching circuit that switches between the first power supply voltage and the second power supply voltage based on the monitor signal and supplies them to the photodetector.

20. The photodetection system according to claim 19, comprising a peripheral device connected to the photodetector, wherein the monitor signal generation unit generates the monitor signal including information regarding the power supply voltage supplied to the peripheral device, and the power supply device controls the power supply voltage supplied to the peripheral device based on the monitor signal.

Images