Patent ID: 12262155

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will now be described with reference to the accompanying drawings. The embodiments can be arbitrarily combined as long as there is no contradiction. In each of the embodiments described below, an imaging device will be mainly described as an example of a photoelectric conversion device. However, the embodiments are not limited to the imaging device, and can be applied to other examples of the photoelectric conversion device. For example, the embodiments can be applied to a distance measuring device (device such as distance measurement using focus detection and TOF (Time Of Flight)), a photometric device (a device such as measuring the amount of incident light), and the like.

First Embodiment

(Overall Configuration)

Referring toFIG.1, a circuit configuration of a photoelectric conversion device10according to the present embodiment will be described. The photoelectric conversion device10is, for example, a CMOS image sensor, and includes a pixel unit11, a driving unit12, a readout unit14, a signal processing unit15, and a timing generator (TG)16.

The pixel unit11includes a plurality of pixels110arranged in a two-dimensional array, and each of the pixels110includes a photoelectric conversion portion that generates and accumulates signal charges according to the amount of received light. Note that in this specification, a row direction indicates a horizontal direction in a drawing, and a column direction indicates a vertical direction in the drawing. Microlenses and color filters may be disposed on the pixels110. The color filters are, for example, primary color filters of red (R), blue (B), and green (Gr, Gb), and are provided in the pixels110in accordance with a Bayer layout. Some of the pixels110are shielded from light as OB (optical black) pixels. The pixel unit11may be provided with NULL pixels which are not connected to the vertical signal line VL. Further, the pixel unit11may include distance measurement rows in which focus detection pixels for outputting pixel signals for focus detection are arranged, and a plurality of imaging rows in which imaging pixels for outputting pixel signals for generating an image is arranged. The vertical signal line VL is provided for each column of the pixels110, and the pixels110in the same column output pixel signals to a common vertical signal line VL. Although not shown, a constant current circuit is connected to each of the vertical signal lines VL, and the constant current circuit functions as a load circuit of the pixels110.

The driving unit12includes shift registers, gate circuits, buffer circuits, and the like, and outputs a control signal to the pixels110based on a vertical synchronization signal, a horizontal synchronization signal, a clock signal, and the like, thereby driving the pixels110for each row. In the present embodiment, the driving unit12can perform vertical scan in which four rows in the pixel unit11are sequentially selected in one horizontal scanning period. The pixels110of the selected four rows are read by the readout unit14via the vertical signal line VL. In the following description, four rows of the vertical signal lines VL that can be read at the same time are referred to as vertical signal lines VL1to VL4. Pixel signals are read from the vertical signal lines VL1to VL4for each horizontal scanning period (hereinafter, it may be referred to as “1H”), and a calculation processing of OB correction value is executed.

The readout unit14can read out pixel signals from the pixels110via the vertical signal lines VL, and includes an amplifier circuit, an ADC (Analog to Digital Converter) circuit, a column memory, a horizontal scanning circuit, and the like. The readout unit14can simultaneously read out pixel signals from the vertical signal lines VL, for example, four rows, and output digital data (pixel values).

The signal processing unit15performs digital signal processing such as OB clamp, digital gain, digital correlated double sampling, digital offset, linearity correction and the like on the pixel data output from the readout unit14. In the present embodiment, the signal processing unit15can perform the digital signal processing such as CDS (Correlated Double Sampling) processing and OB clamp on pixel signals of four rows in one horizontal scanning period. The signal processing unit15includes a LVDS (Low Voltage Differential Signaling) serial output circuit, and outputs the signal-processed digital signal to the outside of the photoelectric conversion device at high speed and at low power consumption.

(Pixel Unit)

FIG.2is a diagram illustrating a configuration example of the pixel110according to the present embodiment. As shown inFIG.1, the pixels110are arranged in a matrix over rows and columns. The pixel110may include, for example, a photoelectric conversion portion111, a transfer transistor112, a floating diffusion (FD)113, an amplification transistor114, a selection transistor115, and a reset transistor116.

The photoelectric conversion portion111includes, for example, a photodiode. An anode of the photoelectric conversion portion111is connected to a ground node (GND), and a cathode of the photoelectric conversion portion111is connected to a source of the transfer transistor112. A drain of the transfer transistor112is connected to a source of the reset transistor116and a gate of the amplification transistor114. The connection node of the drain of the transfer transistor112, the source of the reset transistor116, and the gate of the amplification transistor114is a so-called floating diffusion (FD)113. The FD113includes a capacitance and can function as a charge holding unit and a charge-voltage conversion unit. The drain of the reset transistor116and the drain of the amplification transistor114are connected to a power supply node (voltage VDD). The source of the amplification transistor114is connected to the drain of the selection transistor115. The source of the selection transistor115is connected to the vertical signal line VL. Note that the term “source” and “drain” of a transistor may be changed depending on the conductivity type, application, or the like of the transistor, and the term “source” and “drain” may be reversed.

Each row selection line includes a signal line connected to the gate of the transfer transistor112, a signal line connected to the gate of the reset transistor116, and a signal line connected to the gate of the selection transistor115. A signal line connected to the gate of the transfer transistor112is supplied with a control signal PTX from the driving unit12. A signal line connected to the gate of the reset transistor116is supplied with a control signal PRES from the driving unit12. A signal line connected to the gate of the selection transistor115is supplied with a control signal PSEL from the driving unit12. When each transistor is formed of an N-type transistor, the transistor is turned on by a high-level control signal and turned off by a low-level control signal.

When light is incident on the pixel unit11, the photoelectric conversion unit111of each pixel110converts (photoelectrically converts) the incident light into a charge corresponding to the amount of light and accumulates the generated charge. When the transfer transistor112is turned on, the charge of the photoelectric conversion portion111is transferred to the FD113. The FD113holds the charges transferred from the photoelectric conversion portion111. The charge transferred from the photoelectric conversion portion111is converted into a voltage by a capacitance component of the FD113.

A voltage VDD is supplied to the drain of the amplification transistor114, and a bias current is supplied from the current source118to the source of the amplification transistor114via the selection transistor115. The amplification transistor114functions as an amplification unit (source follower circuit) having a gate as an input node. Accordingly, the amplification transistor114outputs a signal based on the voltage of the FD113to the vertical signal line VL via the selection transistor115. The reset transistor116is turned on and resets the FD113to a voltage corresponding to the voltage VDD.

The transfer transistor112, the reset transistor116, and the selection transistor115of the pixel110are controlled on row-by-row basis by control signals PTX, PRES, and PSEL supplied from the driving unit12. Normal readout of the pixels110will be described. The pixel110is reset except for the accumulation period (between shutter scan and readout scan described later). In the shutter scan, when the reset state by the reset transistor116is released, the photoelectric conversion portion Ill starts accumulation of charges. Next, after a predetermined accumulation time, the readout scan is performed. In the readout scan, the row is selected, and the pixel signal (N-signal) at the reset level of the FD113is read out. Then, the charge of the photoelectric conversion portion111is transferred to the FD113, and a pixel signal (S-signal) based on the charge is read out. Then, the photoelectric conversion portion111and the FD113are reset. By calculating (CDS processing) a difference between the S-signal and the N-signal in the signal processing unit15, a pixel signal based on the charge accumulated in the photoelectric conversion portion111is obtained.

FIGS.3A and3Bare diagrams illustrating a pixel unit according to the present embodiment. The pixel unit11shown inFIG.3Aincludes an opening region11aand OB regions11band11c, and the pixel unit11shown inFIG.3Bincludes an opening region11aand OB regions11b,11cand11d. The opening region11aincludes pixels110which are not shielded from light, and can output pixel signals corresponding to incident light. The OB regions11b,11c, and11dinclude light-shielded pixels110or NULL pixels not connected to the vertical signal line VL, and are used for offset correction or the like. InFIGS.3A and3B, the OB region11bis arranged in the upper rows of the opening region11a, and the OB region11cis arranged in the left columns of the opening region11a. InFIG.3B, the OB region11dis positioned in rows below the opening region11a. The position of the OB region is not limited toFIGS.3A and3B, and the OB region may be provided in the right columns of the opening region11a.

As will be described later, the photoelectric conversion device according to the present embodiment can perform a cyclic readout for continuously reading pixels110of a plurality of rows a plurality of times and a normal readout other than the cyclic readout. For example, as shown inFIG.3A, the cyclic readout may be performed in the upper rows of the divided OB region11b, or may be performed in the OB region11dprovided below the opening region11aas shown inFIG.3B. In either case, the normal readout may typically be performed after the cyclic readout.

(Driving Unit)

The driving unit12according to the present embodiment can realize various kinds of driving in the pixel unit11for shutter driving and calculation of OB values.

FIGS.4A,4B, and4Care diagrams illustrating driving of the pixel unit11by the driving unit12according to the present embodiment. In the drawing, the horizontal axis represents time, and the vertical axis represents the row direction (vertical direction) of the pixel device. Hatched rectangles represent shutter scans, and white rectangles represent readout scans. Numerals in the rectangle in the readout scan correspond to the vertical signal lines VL1to VL4.

FIG.4Ais a diagram illustrating driving of the pixel unit11by the driving unit12according to the present embodiment, and illustrates shutter driving. At time t101, the driving unit12performs the shutter scan by setting the control signals PTX and PRES of the first to fourth rows to a high level, and resets the charges of the photoelectric conversion portions111and FDs113of the pixels110to the voltage VDD. Subsequently, the driving unit12changes the control signals PTX and PRES of the first to fourth rows from the high level to the low level, and the photoelectric conversion portion111starts accumulation of charges according to the incident light. At time t102, the driving unit12sets the control signals PTX and PRES of the fifth to eighth rows to a high level, and resets the charges of the photoelectric conversion portions111and FDs113of the pixels110to the voltage VDD. Subsequently, the driving unit12changes the control signals PTX and PRES from the high level to the low level, and the photoelectric conversion portion111starts accumulation of charges according to the incident light. Similarly, after time t103, the driving unit12performs the shutter scan for every four rows.

At time t111to t112after a predetermined accumulation time (exposure time) from the shutter scan, the driving unit12performs the readout scan of the first to fourth rows. That is, the driving unit12sets the control signal PSEL of the first to fourth rows to a high level, and turns on the selection transistors115. Thus, the N-signal at the time of the reset is output from the pixel110to each of the vertical signal lines VL1to VL4. Subsequently, the driving unit12sets the control signals PTX of the first to fourth rows to a high level, and turns on the transfer transistors112. Thus, the charges accumulated in the photoelectric conversion portion111are transferred to the FD113. The voltage of the FD113decreases according to the transferred charge, and the S-signal is output from the source of the amplification transistor114to each of the vertical signal lines VL1to VL4via the selection transistors115. That is, the pixel signals of the pixels110in the first to fourth rows are simultaneously read out via the vertical signal lines VL1to VL4.

At time t112to t113, the driving unit12sets the control signal PSEL of the fifth to eighth rows to a high level, and then sets the control signal PTX to a high level. Thus, pixel signals are sequentially output from the pixels110in the fifth to eighth rows to the vertical signal lines VL1to VL4. In this manner, in the pixel unit11, the readout scan is performed for every four rows. Numerals in the rectangle of the readout scan correspond to the vertical signal lines VL1to VL4. That is, the pixels110in the first row, the fifth row, the ninth row, . . . , and the (4×N−3)th row are read out via the vertical signal line VL1, and the pixels110in the second row, the sixth row, the tenth row, . . . , and the (4×N−2)th row are read out via the vertical signal line VL2. The pixels110of the third, seventh, eleventh, . . . , and (4×N−1)th rows are read out via the vertical signal line VL3, and the pixels110of the fourth, eighth, twelfth, . . . , and (4×N)th rows are read out via the vertical signal line VIA.

The driving unit12may perform various kinds of driving as well as the normal readout driving, and may perform readout of the NULL pixels, for example. Further, the driving unit12may perform N-N readout driving for reading the S-signal in a state where the transfer transistor is turned off after reading the N-signal. Further, the driving unit12can perform the cyclic readout driving for repeatedly reading out a predetermined region.

FIG.4Bis a diagram illustrating driving of the pixel unit11by the driving unit12according to the present embodiment, and shows driving of the cyclic readout. As shown inFIGS.3A and3B, the cyclic readout can be performed in the OB region11bor the OB region11d.

At time t201to t202, the driving unit12sequentially turns on the selection transistors115and the transfer transistors112of the first to fourth rows, and outputs the pixel signals of the N-signals and the S-signals from the pixels110to the vertical signal lines VL1to VL4. Similarly, at time t202to t203, the driving unit12outputs the pixel signals from the pixels110in the fifth to eighth rows to the vertical signal lines VL1to VL4, and at time t203to t204, the driving unit12outputs the pixel signals from the pixels110in the ninth to twelfth rows to the vertical signal lines VL1to VL4. At time t204to t205, the driving unit12outputs the pixel signals from the pixels110in the first to fourth rows to the vertical signal lines VL1to VL4again, and at time t205to t206, the driving unit12outputs the pixel signals from the pixels110in the fifth to eighth rows to the vertical signal lines VL1to VL4. Similarly, in the pixels110of the first to twelfth rows, the readout scan is repeatedly performed every four rows.

In the cyclic readout described above, the shutter scan is not necessarily performed, and in this case, the period of the readout scan corresponds to the accumulation time. Although the shutter scan may be performed between the readout scan and the next readout scan, the cycle of the readout scan becomes the upper limit of the accumulation time. Although there is a restriction on the accumulation time, a large amount of data can be obtained in a short time from a small region by the cyclic readout.

FIG.4Cis a diagram illustrating driving of the pixel unit11by the driving unit12according to the present embodiment, and illustrates driving in which the normal readout is performed after the cyclic readout.

In the following description of the present embodiment, it is assumed that the normal readout is performed after the cyclic readout is performed in a part of the OB region11b. The normal readout can be performed in the remaining region where the cyclic readout is not performed in the OB region11b, the OB region11c, the opening region11a, and the like. As shown inFIG.3A, the upper region of the OB region11bmay be assigned to the cyclic readout, and the lower region of the OB region11bmay be assigned to the normal readout. Further, as shown inFIG.3B, the OB region11dpositioned below the opening region11amay be assigned to the cyclic readout, and the OB region11bpositioned above the opening region11amay be assigned to the normal readout. When the cyclic readout is performed in the opening region11a, the N-N readout may be preferably performed. In either case, the cyclic readout may be followed by the normal readout.

In the following description, it is assumed that the cyclic readout is performed in the 12 rows of the OB region11b, for example. The readout for three horizontal scanning periods is repeated eight times, and the cyclic readout data for 24 horizontal scanning periods is obtained. The cyclic readout data may be referred to as preliminary data or reference data, and the normal readout data may be referred to as main data.

In the cyclic readout period T1, the cyclic readout is performed for every four rows in the 12 rows of the OB region11b. That is, at time t301to t302, the driving unit12performs the readout scan of the first to fourth rows, and outputs the pixel signals of the N-signal and the S-signal from the pixels110to the vertical signal lines VL1to VL4. Similarly, the driving unit12performs the readout scan (time t302to t303) of the fifth to eighth rows, the readout scan (time303to t304) of the ninth to twelfth rows, and the readout scan (time t304to t305) of the first to fourth rows. Further, at time t305to t306, the driving unit12performs the readout scan of the fifth to eighth rows and shutter scan of the thirteenth to sixteenth rows of the opening region11a. Similarly, the shutter scan is performed following the cyclic readout. The pixel signal at the time of the cyclic readout is used as an initial value of a first correction component described later.

In the normal readout period T2after the cyclic readout period T1, the normal readout is performed for every four rows in the remaining region, the OB region11c, and the opening region11ain which the cyclic readout is not performed in the OB region11b. At time310to t311, the driving unit12outputs the pixel signals of the N-signals and the S-signals from the pixels110of the thirteenth to sixteenth rows to the vertical signal lines VL1to VL4. Similarly, at time t311to t312, the driving unit12outputs pixel signals from the pixels110in the seventeenth to twentieth rows to the vertical signal lines VL1to VL4. The pixel signal in the period T20(time t310to t312) is used as an initial value of the filter unit of the signal processing unit15as described later. In a period T21after the time t312, the signal processing unit15calculates a second correction component depending on the vertical position using the pixel signals at the time of the normal readout. Further, the signal processing unit15continues to update the first correction components sequentially using the pixel signals and the second correction components. The details will be described later.

(Signal Processing Unit)

FIG.5is a block diagram of the signal processing unit15according to the present embodiment. The signal processing unit15includes calculation units15R,15B,15Gr, and15Gb for each color of the color pixels110arranged in a Bayer layout. That is, the signal processing unit15includes a calculation unit15R that processes the signals of the R pixels110, a calculation unit15B that processes the signals of the B pixels110, a calculation unit15Gr that processes the signals of the Gr pixels110, and a calculation unit15Gb that processes the signals of the Gb pixels110. The calculation unit15R processes the signals of the R pixels110read through the vertical signal lines VL1and VL3, and the calculation unit15B processes the signals of the B pixels110read through the vertical signal lines VL2and VL4. The calculation unit15Gr processes the signals of the Gr pixels110read out via the vertical signal lines VL1and VL3, and the calculation unit15Gb processes the signals of the Gb pixels110read out via the vertical signal lines VL2and VL4.

The calculation unit15R includes CDS calculation units151R and152R, a memory unit153R, an OB clamp calculation unit150R, and a data output unit154R. The CDS calculation units151R and152R calculate a difference value between the S-signal and the N-signal read from the column memory in the readout unit14via the vertical signal line VL1, and output the difference value to the memory unit153R. That is, the CDS calculation unit151R calculates a difference value between the S-signal R_VL1S and the N-signal R_VL1N read from the R pixel110via the vertical signal line VL1. Similarly, the CDS calculation unit152R calculates a difference value between the S-signal R_VL3S and the N-signal R_VL3N read from the R pixel110via the vertical signal line VL3.

The memory unit153R can hold data of two rows (one horizontal scanning period) of the R pixels110read out via the vertical signal lines VL1and VL3. The memory unit153R alternately outputs the data of the vertical signal line VL1and the data of the vertical signal line VL3to the OB clamp calculation unit150R every half (½) horizontal scanning period. At this time, the memory unit153R adds an identifier (vertical signal line identifier) to the date. The identifier indicates the vertical signal line VL from which each data is read out. The OB clamp calculation unit150R calculates the OB value mainly using the data of the OB region11band subtracts the OB value from the data of the opening region11ato realize the OB clamp operation (OB value correction operation). The OB value includes a dark current, a circuit-dependent component, and the like, and the OB value includes a difference value for each vertical signal line VL, i.e., a difference value between the vertical lines. Therefore, the OB clamp calculation unit150R separately calculates the OB value of the vertical signal line VL1and the OB value of the vertical signal line VL3. The OB clamp calculation unit150R outputs the OB clamped data to the data output unit154R. The data output unit154R converts the input data into a predetermined format and outputs the converted data to the outside of the device.

The other calculation units15B,15Gr, and15Gb are configured in the same manner as the calculation unit15R. That is, the calculation unit15B can perform the CDS processing and the OB clamp of data of the B pixels110read from the vertical signal lines VL2and VL4. Further, the calculation unit15Gr can perform the CDS processing and OB clamp of data of the Gr pixels110read from the vertical signal lines VL1and VL3, and the calculation unit15Gb can perform the CDS processing and the OB clamp of data of the Gb pixels110read from the vertical signal lines VL2and VL4. In this way, the calculation units15R,15B,15Gr, and15Gb can calculate the OB correction value for each color of the color pixels110and perform the OB clamp.

(OB Clamp Calculation Unit)

FIG.6is a block diagram of the OB clamp calculation unit150R in the calculation unit15R. Since the other OB clamp calculation units150B,150Gr, and150Gb are similarly configured, the OB clamp calculation unit150R will be described below. As shown inFIG.6, the OB clamp calculation unit150R includes a defect correction unit1501, an averaging unit1502, a first processing unit1503, a second processing unit1504, a subtraction unit1505, and a control unit1506. When the OB value calculation is performed in the data input to the OB clamp calculation unit150R, the data is input to the defect correction unit1501. When the OB clamp is performed in the data input to the OB clamp calculation unit150R, the data is input to the subtraction unit1505.

The defect correction unit1501performs defect correction processing using a predetermined value or an OB value calculated by the second processing unit1504as a reference value. Specifically, the defect correction unit1501calculates a normal range of the OB value by executing a predetermined calculation on the reference value, and determines data exceeding the normal range as defect data. The data determined as the defect data is replaced with a reference value or deleted. This prevents the data exceeding the normal range from affecting the OB value calculation.

The averaging unit1502divides the integrated value of the data by the number of data over a half (½) horizontal scanning period, i.e., one horizontal scanning period for each vertical signal line VL, and calculates an average value. The first processing unit1503calculates a first correction component for each vertical signal line VL using the average value calculated by the averaging unit1502and the second correction component calculated by the second processing unit1504. The second processing unit1504calculates the second correction component using the average value calculated by the averaging unit1502and the first correction component calculated by the first processing unit1503. The second processing unit1504calculates an OB value from the first correction component and the second correction component, and outputs the OB value to the subtraction unit1505and the defect correction unit1501.

The subtraction unit1505subtracts the OB value from the input data and performs the OB clamp. The control unit1506controls the overall operation of the OB clamp calculation unit150R. For example, the control unit1506determines whether or not the input data is data in a region to be subjected to OB value calculation. Further, the control unit1506controls switching of operation modes of the first processing unit1503and the second processing unit1504.

FIGS.7A,7B,7C, and7Dare block diagrams of the first processing unit1503and the second processing unit1504according to the present embodiment.FIG.7Aillustrates the overall configuration of the first processing unit1503and the second processing unit1504. InFIGS.7B,7C, and7D, a block indicated by a solid line represents an operation state, and a block indicated by a broken line represents a non-operation state.

The first processing unit1503includes a subtraction unit1530, a filter unit1531, a filter unit1532, an average value calculation unit1533, and multiplexers1534and1535. Each of the multiplexers1534and1535includes a plurality of switch circuits, and switches the switch circuits according to the operation state of the signal processing unit15. The first processing unit1503performs predetermined signal processing on the average values R1and R3output from the averaging unit1502inFIG.6, and calculates a first correction component Va dependent on the vertical signal line VL. The second processing unit1504includes a subtraction unit1540, a filter unit1541, and an addition unit1542, and updates the second correction component Vb according to the vertical position using the first correction component Va. The addition unit1542outputs an addition value of the first correction component Va and the second correction component Vb as the OB value.

In the above-described configuration, each unit may share a hardware configuration as long as equivalent functions can be available. For example, since the filter units1531and1532alternately operate, the filter units1531and1532may be configured by a common circuit.

FIG.7Bis a block diagram of the first processing unit1503and the second processing unit1504according to the present embodiment, and illustrates an operation state in the cyclic readout period T1(time t301to t310) ofFIG.4C. The filter unit1531calculates an average value Va1obtained by dividing the integrated value of the average value data R1from the averaging unit1502inFIG.6by the number of horizontal scanning periods. That is, the filter unit1531calculates the average value Va1of the data R1of the vertical signal line VL1during the same period. Similarly, the filter unit1532calculates the average value Va3of the data R3of the vertical signal line VL3during the same period. In this manner, the filter units1531and1532calculate the average values Va1and Va3for each vertical signal line VL based on the cyclic readout data R1and R3. Further, the average value calculation unit1533calculates an average value Va0of the average value Va1and the average value Va3. The average value Va0represents an average value of data of all the vertical signal lines VL in the cyclic readout period. The calculated average values Va1, Va3, and Va0are classified according to the vertical signal line identifier as initial values of a first correction component to be described later, and are held in the filter unit1531, the filter unit1532, and the average value calculation unit1533. At the end of the cyclic readout (time310), the first correction components Va1, Va3, and Va0held in the filter units1531and1532and the average value calculation unit1533are represented by the following formulas (1) to (3), respectively.

Va1=1N1⁢∑k=1N1R1,k(1)Va3=1N1⁢∑k=1N1R3,k(2)Va0=12⁢N1⁢∑k=1N1(R1,k+R3,k)(3)

In the formulas (1) to (3), “R1, k” and “R3, k” represent data R1and R3at the time of the cyclic readout of the vertical signal lines VL1and VL3in the k-th horizontal scanning period, respectively. “N1” denotes the number of horizontal scanning periods of the cyclic readout, and “k” denotes the k-th horizontal scanning period among the first to N1-th horizontal scanning periods.

In general, since a difference between the vertical lines does not depend on the accumulation time, a difference between the first correction component Va1and the first correction component Va1corresponds to the difference between the vertical lines. Further, averaging the data R1and R3at the time of the cyclic readout for each horizontal scanning period in the horizontal scanning period of N1can reduce random noise included in the data R1and R3. The first correction components Va1, Va3, and Van as initial values may be representative values of respective target regions (vertical signal lines VL), and may be median values, for example.

FIG.7Cis a block diagram of the first processing unit1503and the second processing unit1504according to the present embodiment, and illustrates an operation state in the normal readout period T20(time t310to t312) ofFIG.4C. As described above, the data S1and S3at the time of the normal readout are included in the period T20of the several horizontal scanning periods in the beginning of the normal readout period T2. The data S1and S3in the period T20are used to calculate the initial value of the filter unit1541. The data S1and S3averaged by the averaging unit1502are input to the second processing unit1504. The first correction component Va calculated by the average value calculation unit1533is output to the second processing unit1504, and the subtraction unit1540calculates a difference value between the data S1and S3and the first correction component Va. The filter unit1541obtains an average value Vb0obtained by dividing the integrated value of the difference by the number of horizontal scanning periods N2. The average value Vb0is used as an initial value of the second correction component Vb described later. At the time (312) when the first period T20of the normal readout ends, the second correction component Vb0held in the filter unit1541is represented by the following formula (4).

Vb0=12⁢N2⁢∑k=1N2(S1,k+S3,k)-Va0(4)

In the formula (4), “N2” represents the number of horizontal scanning periods in the period T20, and “S1, k” and “S3, k” represent the data S1and S3at the time of normal readout of the vertical signal lines VL1and VL3in the k-th horizontal scanning period of the normal readout region, respectively. By subtracting the first correction component Va0calculated by the formula (3) from the sum of the data S1and S3, it is possible to reduce level difference (DC difference) between the data R1and R3at the time of the cyclic readout and the data S1and S3at the time of normal readout. This ensures continuity of smoothing processing, which will be described later, and makes it possible to suppress an abrupt change in value. The level difference between the data R1and R3and the data S1and S3is mainly due to the difference in the accumulation time.

FIG.7Dis a block diagram of the first processing unit1503and the second processing unit1504according to the present embodiment, and illustrates the operation state in the normal readout period T21(after time t312) ofFIG.4C. In the period T21, the normal readout is performed after the N2-th horizontal scanning period. The subtraction unit1530sequentially updates the first correction components Va1and Va3based on the difference values between the data S1and S3output from the averaging unit1502and the second correction component Vb. The calculated difference values are classified according to the vertical signal line identifier and input to the filter unit1531or the filter unit1532. The filter units1531and1532perform smoothing processing (low-pass filter processing) using the input difference value and the current calculation result held in the filter units1531and1532. The smoothing processing may be performed, for example, by the following a primary IIR (Infinite Impulse Response) processing.
Va1,N={Va1,(N−1)×A1+(S1,N−Vb(N−1))×(1−A1)}  (5)
Va3,N={Va3,(N−1)×A1+(S3,N−Vb(N−1))×(1−A1)}  (6)

In the formulas (5) and (6), “A1” denotes an attenuation coefficient of the primary IIR treatment, and is a value in the range of 0<A1<1. Further, “Va1, N” and “Va3, N” represent the first correction component Va updated in the N-th horizontal scanning period of each of the vertical signal lines VL1and VL3, and “Vb(N−1)” represents the second correction component Vb in the (N−1)-th horizontal scanning period. That is, the first correction component Va for each vertical signal line VL is updated using the second correction component Vb depending on the vertical position and the data S.

The subtraction unit1530is not necessarily required, and the input data “S1, N” and “S3, N” may be input to the filter units1531and1532. However, when the image includes steep vertical shading, it is preferable to provide the subtraction unit1530. The reason will be described in detail below. The calculation results of formulas (5) and (6) are updated only once every horizontal scanning period. Therefore, when the image includes a steep vertical shading, a relatively large attenuation coefficient A1is required to smooth the vertical shading. That is, in order to adapt to the steep vertical shading, the cutoff frequency of the low-pass filter should be high. On the other hand, in order to avoid the influence of noise, a small value of the attenuation coefficient A1is preferable at the time of high sensitivity imaging or the like. Thus, the attenuation coefficient A1may be defined by a tradeoff between contradicting factors. When the subtraction unit1530is provided, since the second correction component Vb is subtracted from the data S1and S3, the influence of the steep vertical shading can be reduced. Since the calculation result of the filter unit1541is updated twice in one horizontal scanning period, it is possible to easily adapt to the steep vertical shading as compared with the calculation results of the filter units1531and1532. Thus, the subtraction unit1530is particularly effective when the vertical shading is large.

The subtraction unit1540calculates a difference between the input data S1and S3and the first correction components Va1and Va3. Since the first correction components Va1and Va3include a difference between the vertical lines, the difference between the vertical lines is reduced or not included in the difference value obtained by subtracting the first correction components Va1and Vas. The difference value obtained by the subtraction unit1540is input to the filter unit1541. The data S1of the vertical signal line VL and the data S3of the vertical signal line VL3are alternately input to the filter unit1541every half (½) horizontal scanning period. The filter unit1541performs smoothing processing using the input difference and the calculation result held in the filter unit1541. The smoothing processing can be performed, for example, by the following primary IIR processing.
VbN={Vb(N−1)/2×A2+(S1,N−Va1,N)×(1−A2)}  (7)

In the formula (7), “i” denotes the identification number of the vertical signal line. “A2” denotes an attenuation coefficient of the primary IIR processing, and is a value in a range of 0<A2<1. “VbN” represents the second correction component in the N-th horizontal scanning period. The second correction component VbNmay vary depending on the vertical position, but is a value common to the vertical signal lines VL1and VL3. In the formula (7), the first correction component Va1, which is the calculation result of the filter unit1531, is referred to for processing the data S1of the vertical signal line VL1, and the first correction component Va3, which is the calculation result of the filter unit1532, is referred to for processing the data S3of the vertical signal line VL3. The second correction component Vb is common to the vertical signal lines VL1and VL3without depending on the vertical signal line VL. Therefore, the second correction component Vb obtained from the data S1of the vertical signal line VL1can be referred to with respect to the second correction component Vb of the vertical signal line VL3, and the second correction component Vb obtained from the data S3of the vertical signal line VL3can be referred to with respect to the second correction component Vb of the vertical signal line VL1. In the formula 7, “Vb(N−1)/2” indicates that the next second correction component Vb is obtained from the second correction component Vb before the half (½) horizontal scanning period. Even if a shading exists in the vertical direction, the filter unit1532can output the second correction component Vb whose noise is reduced while adapting to the vertical shading.

The addition unit1542adds the updated first correction component Va and the second correction component Vb. and outputs the added value as an OB value (offset value). By subtracting the OB value from the pixel data in the opening region11a, the subtraction unit1505of the OB clamp calculation unit150can realize the OB value correction to reduce the difference between the vertical lines and the shading in the vertical direction.

As described above, in the photoelectric conversion device according to the present embodiment, the OB value is decomposed into the first correction component and the second correction component, and the first correction component is sequentially updated using the second correction component. First, the plurality of the first correction components Va including difference between the vertical lines is obtained from the data R at the time of the cyclic readout. The first correction component Va of each of the plurality of vertical signal lines VL is sequentially updated using the second correction component common to the plurality of first correction components Va and the data S at the time of the normal readout. Therefore, according to the present embodiment, it is possible to realize high-precision OB correction without providing a large number of OB regions.

In particular, the photoelectric conversion device according to the present embodiment subtracts the first correction component Va from the data S at the time of the normal readout to obtain the second correction component Vb that is independent of the vertical signal line VL. Therefore, when calculating the second correction component Vb, it is not necessary to obtain the correction value separately for each vertical signal line VL, and it is possible to perform the high-precision OB correction with a small amount of data and a small OB region.

Further, the initial value of the first correction component Va can be calculated from the data R in a smaller area by the cyclic readout. The number of repetitions of the cyclic readout is determined according to the amount of noise so that difference between the vertical lines can be obtained from a small region with high accuracy.

Here, effects of the present embodiment will be described by comparing with other configurations. In general, the OB value includes components dependent on a horizontal position, components dependent on a vertical position, and components independent of a position. The OB clamp in this embodiment may be configured to correct the components dependent on the vertical position and the components independent of the position, and the components independent of the horizontal position may be corrected by another configuration. The components dependent on the vertical position and components independent of the position include components dependent on the vertical signal line VL and other components such as dark current. Here, it is assumed that among the components dependent on the vertical position, the components dependent on the vertical signal line are small.

As another method of OB correction, it would be possible to obtain the OB value by obtaining data for each row and smoothing data in the vertical direction independently for each vertical signal line. In this method, a larger OB region is required according to the number of vertical signal lines in order to reduce random noise. In addition, the sampling interval is increased, and it is difficult to adapt to the vertical shading.

On the other hand, in the present embodiment, as described above, the OB value is decomposed into the first correction component Va and the second correction component Vb, and the first correction component Va is sequentially updated using the second correction component Vb. Therefore, when calculating the second correction component Vb, it is not necessary to separately obtain the correction value for each vertical signal line VL, and it is not necessary to provide a large number of OB regions corresponding to the number of vertical signal lines VL. Since the first correction component Va is sequentially updated in the data S at the time of the normal readout, the first correction component Va can be adapted to the vertical shading. Therefore, according to the present embodiment, it is possible to obtain the OB value with high accuracy without requiring a large number of OB regions.

In the above description, although the number of vertical signal lines VL is four, the number of vertical signal lines VL may be any number greater than or equal to two. Further, although the first correction component Va is classified (calculated) for each vertical signal line VL, it may be classified for each group of other circuit elements. For example, when the floating diffusion is shared by a plurality of the pixels, there may be a difference in the OB values depending on the order of pixels for transferring charges to the floating diffusion. In this case, the first correction components Va may be classified according to the order of pixels for transferring charges to the floating diffusion FD. When the pixels are distance measuring pixels including a plurality of photoelectric conversion portions, the first correction components Va may be classified according to the driving method of the pixels. For example, the first correction component Va may be classified for each reading method of the image A, the image B, and the image (A+B). Further, when the image A is intermittently read out, the first correction components Va may be classified according to whether or not the image A is read out. Also, a plurality of categories may be combined. The larger the number of classifications, the higher the effect of calculating the OB value with high accuracy.

Further, although the filter units1531,1532, and1541have been described as a primary IIR, other IIRs such as a secondary IIR, FIR (Finite Impulse Response) or the like may also be used.

Further, in the cyclic readout, the N-N readout and the NULL readout may be combined. Alternatively, if the vertical scan is thinned out in the normal readout and all the rows are not read out, the non-readout rows may be used for calculating the OB values. When the pixel110used for calculating the OB values is included in the opening region11a, the N-N readout is preferable. Thus, the OB values such as a difference between the vertical lines can be obtained using various readout methods.

The number of the cyclic readouts (the number of horizontal scanning periods N1) can be arbitrarily defined. As the number of cycles increases, the noise included in the initial value of the first correction component Va is reduced. On the other hand, from the viewpoint of power consumption and frame rate, the number of cycles may be preferably small. The number of cycles may be defined by a tradeoff in multiple factors. For example, the number of cycles may be dynamically changed depending on the mode of vertical scan, ISO (International Organization for Standardization) sensitivity, temperature, etc.

Although the vertical signal line identifier is used to classify the first correction components Va, the vertical signal line identifier is switched every half (½) horizontal scanning period. Therefore, the vertical signal line identifier is not necessarily required, and the vertical signal line may be discriminated from the timing of the horizontal scanning.

Second Embodiment

Next, a photoelectric conversion system according to the present embodiment will be described. Although the OB clamp calculation is performed in the photoelectric conversion device in the first embodiment, the OB clamp calculation may be performed outside the photoelectric conversion device in the present embodiment.

FIG.8illustrates a configuration example of a photoelectric conversion system according to the present embodiment. The photoelectric conversion system includes a photoelectric conversion device10and a calculation device80. The calculation device80can execute a predetermined correction calculation by receiving data from the photoelectric conversion device10via the communication line20and executing a computer program. The communication line20may be wired or wireless, and may be public wireless communication or short-range wireless communication. The calculation device80can perform the functions of the OB clamp calculation unit150in the first embodiment, and receives data input to the OB clamp calculation unit150. The calculation device80can store data of one frame including the cyclic readout data and the normal readout data in a memory in the calculation device80, and can repeatedly refer to the data stored in the memory in the calculation processing. The calculation device80may be a standalone personal computer, an edge terminal, a server on a cloud, or the like.

FIG.9is a flowchart illustrating the operation of the calculation device80according to the present embodiment. In step S101, the calculation device80calculates the first correction component Va for each vertical signal line in the first region of the data of one frame stored in the memory. Here, the first region may be a data region corresponding to the OB region11bor the like. The calculation device80classifies the data R at the time of cyclic readout for each vertical signal line VL, and calculates an average value of the classified data R. The average value is calculated in the same manner as in the formulas (1) and (2) of the first embodiment. The calculated average value here is used as an initial value of the first correction component Va.

In step S102, the calculation device80calculates the average value S for each row in the second region, which is the correction value calculation region of the data of one frame. Since the processes of steps S101and S102are independent, the process of step S102may be executed prior to the process of step S101.

In step S103, the calculation device80calculates a difference value obtained by subtracting the first correction component Va of the vertical signal line VL from the average value S calculated in the step S102.

In step S104, the calculation device80performs a curve approximation on the difference values calculated in the step S103in the vertical direction.FIG.10is a diagram illustrating an example of the curve approximation according to the present embodiment. InFIG.10, the horizontal axis represents the difference values, and the vertical axis represents the vertical position (row direction, i.e., the Y coordinate of the image). Each point corresponds to a difference for each row, and a solid line represents a curve obtained by function-approximating the difference. Thus, the correction value corresponding to the shading component in the vertical direction can be obtained by the curve approximation. The curve may be approximated by a polynomial for the Y coordinate, or may be approximated by an arbitrary function such as a spline curve. The curve obtained in this manner represents the second correction component Vb having difference values depending on the vertical position N.

In step S105, the calculation device80calculates a difference value obtained by subtracting the second correction component Vb in the step S104from the average value S of each row calculated in the step S102.

In step S106, the calculation device80performs the curve approximation on the difference values in the step S105in the same manner as in the step S104. The curve is obtained for each vertical signal line VL. The calculation device80updates the obtained curve as the first correction component Va.

In step S107, the calculation device80determines whether or not the updated result has converged. That is, in the updating processing of the steps S104and S106, the calculation device80calculates the difference values respectively between the first correction component Va and the second correction component Vb which are before updated and the first correction component Va and the second correction component Vb which are updated, and the calculation device80determines whether or not the difference values are equal to or smaller than a predetermined value. When the updated result is not converged, that is, when the difference values exceed the predetermined value (NO in step S107), the calculation device80repeats the processing of the steps S103to S107. When the updated result is converged, that is, when the difference values are equal to or less than the predetermined value (YES in step S107), the calculation device80performs the processing of step S108. The calculation device80repeats the processing of the steps S103to S107until the difference values converge, and continues updating of the first correction component Va and the second correction component Vb. Thus, errors of the first correction component Va and the second correction component Vb are reduced.

In step S108, the calculation device80calculates an OB value obtained by adding the second correction component Vb in the step S104and the first correction component Va in the step S106. The calculation device80can perform high-precision OB correction by subtracting the OB value from the pixel data in the opening region11a.

Thus, the correction calculation in the calculation device80is performed. In the present embodiment, since data is repeatedly referred to, a relatively large memory is required, but precise correction can be obtained.

In the present embodiment, the curve approximation in the vertical direction is obtained in order to adapt to the shading in the vertical direction. Moreover, in order to adapt to the shading including the shading in the horizontal direction, the curved surface approximation may be performed in the three-dimensional space of the vertical direction, the horizontal direction, and the pixel value.

Third Embodiment

An imaging system according to the present embodiment will be described.FIG.11is a block diagram illustrating a schematic configuration of an imaging system according to the present embodiment. The imaging system200illustrated inFIG.11includes an imaging device201, a lens202for forming an optical image of a subject on the imaging device201, an aperture204for varying the amount of light passing through the lens202, and a barrier206for protecting the lens202. The lens202and the aperture204are optical systems that collect light on the imaging device201. The imaging device201is the photoelectric conversion device10described in the first or the second embodiment, and converts an optical image formed by the lens202into image data.

The imaging system200also includes a signal processing unit208that processes an output signal output from the imaging device201. The signal processing unit208generates image data from a digital signal output from the imaging device201. The signal processing unit208performs various corrections and compressions as needed to output image data. The imaging device201may include an AD converter that generates a digital signal to be processed by the signal processing unit208. The AD conversion unit may be formed in a semiconductor layer (semiconductor substrate) in which the photoelectric conversion portion of the imaging device201is formed, or may be formed in a semiconductor substrate different from the semiconductor layer in which the photoelectric conversion portion of the imaging device201is formed. The signal processing unit208may be formed on the same semiconductor substrate as the imaging device201.

The imaging system200further includes a memory unit210for temporarily storing the image data, and an external interface unit (external I/F unit)212for communicating with an external computer or the like. Further, the imaging system200includes a storage medium214such as a semiconductor memory for storing or reading the imaging data, and a storage medium control interface unit (storage medium control I/F unit)216for storing or reading the imaging data on or from the storage medium214. The storage medium214may be built in the imaging system200, or may be detachable.

Further, the imaging system200includes a general control/operation unit218that controls various calculations and the overall digital still camera, and a timing generation unit220that outputs various timing signals to the imaging device201and the signal processing unit208. Here, the timing signal or the like may be input from the outside, and the imaging system200may include at least the imaging device201and a signal processing unit208that processes an output signal output from the imaging device201.

The imaging device201outputs the imaging signal to the signal processing unit208. The signal processing unit208performs predetermined signal processing on the imaging signal output from the imaging device201, and outputs image data. The signal processing unit208generates an image using the imaging signal.

As described above, according to the present embodiment, it is possible to realize an imaging system to which the photoelectric conversion device10according to the first or the second embodiment is applied.

Fourth Embodiment

An imaging system and a mobile body according to the present embodiment will be described.FIGS.12A and12Bare diagrams illustrating a configuration of an imaging system and a mobile body according to the present embodiment.

FIG.12Aillustrates an example of an imaging system relating to a vehicle-mounted camera. The imaging system300includes an imaging device310. The imaging device310is the photoelectric conversion device10described in the first or the second embodiment. The imaging system300includes an image processing unit312that performs image processing on a plurality of image data acquired by the imaging device310, and a parallax acquisition unit314that calculates parallax (phase difference of parallax images) from the plurality of image data acquired by the imaging system300. The imaging system300includes a distance acquisition unit316that calculates a distance to an object based on the calculated parallax, and a collision determination unit318that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit314and the distance acquisition unit316are examples of a distance information acquisition means that acquires distance information to the object. That is, the distance information is information on a parallax, a defocus amount, a distance to an object, and the like. The collision determination unit318may determine the collision possibility using any of the distance information. The distance information obtaining means may be configured by dedicated hardware or software modules. Further, it may be configured by FPGA (Field Programmable Gate Array). ASIC (Application Specific Integrated circuit), or the like, or may be configured by a combination of these.

The imaging system300is connected to the vehicle information acquisition device320, and can obtain vehicle information such as a vehicle speed, a yaw rate, and a steering angle. Further, the imaging system300is connected to a control ECU330, which is a control unit that outputs a control signal for generating a braking force to the vehicle, based on the determination result of the collision determination unit318. The imaging system300is also connected to an alert device340that issues an alert to the driver based on the determination result of the collision determination unit318. For example, when the collision possibility is high as the determination result of the collision determination unit318, the control ECU330performs vehicle control to avoid collision and reduce damage by braking, returning an accelerator, suppressing engine output, or the like. The alert device340alerts a user by sounding an alert such as a sound, displaying alert information on a screen of a car navigation system or the like, or giving vibration to a seat belt or a steering wheel.

In the present embodiment, the imaging system300images the periphery of the vehicle, for example, the front or the rear.FIG.12Billustrates an imaging system in the case of imaging an image in front of the vehicle (an imaging range350). The vehicle information acquisition device320sends an instruction to the imaging system300or the imaging device310. With such a configuration, the accuracy of distance measurement can be further improved.

In the above description, an example has been described in which control is performed so as not to collide with other vehicles, but the present invention is also applicable to control of automatic driving following other vehicles, control of automatic driving so as not to go out of a lane, and the like. Further, the imaging system is not limited to a vehicle such as a host vehicle, and can be applied to, for example, a mobile body (moving device) such as a ship, an aircraft, or an industrial robot. In addition, the present invention can be applied not only to a mobile body but also to a various equipment such as an intelligent transport systems (ITS).

Fifth Embodiment

Equipment according to the present embodiment will be described.FIG.13is a block diagram showing a schematic configuration of equipment according to the present embodiment.

FIG.13is a schematic diagram illustrating equipment EQP including the photoelectric conversion device APR. The photoelectric conversion device APR has the function of the photoelectric conversion device10of the first embodiment. All or a part of the photoelectric conversion device APR is a semiconductor device IC. The photoelectric conversion device APR of this example can be used, for example, as an image sensor, an AF (Auto Focus) sensor, a photometry sensor, or a distance measurement sensor. The semiconductor device IC has a pixel region PX in which pixel circuits PXC including photoelectric conversion portion are arranged in a matrix. The semiconductor device IC can have a peripheral region PR around the pixel region PX. Circuits other than the pixel circuits can be arranged in the peripheral region PR.

The photoelectric conversion device APR may have a structure (chip stacked structure) in which a first semiconductor chip provided with a plurality of photoelectric conversion portions and a second semiconductor chip provided with peripheral circuits are stacked. Each peripheral circuit in the second semiconductor chip can be a column circuit corresponding to a pixel column of the first semiconductor chip. The peripheral circuits in the second semiconductor chip may be matrix circuits corresponding to the pixels or pixel blocks of the first semiconductor chip. As a connection between the first semiconductor chip and the second semiconductor chip, a through electrode (TSV), an interchip wiring by direct bonding of a conductor such as copper, a connection by micro bumps between chips, a connection by wire bonding, or the like can be adopted.

In addition to the semiconductor device IC, the photoelectric conversion device APR may include a package PKG that accommodates the semiconductor device IC. The package PKG may include a base body to which the semiconductor device IC is fixed, a lid body made of glass or the like facing the semiconductor device IC, and a connection member such as a bonding wire or a bump that connects a terminal provided on the base body to a terminal provided on the semiconductor device IC.

The equipment EQP may further comprise at least one of an optical device OPT, a control device CTRL, a processing device PRCS, a display device DSPL, a storage device MMRY, and a machinery device MCHN. The optical device OPT corresponds to the photoelectric conversion device APR as a photoelectric conversion device, and is, for example, a lens, a shutter, or a mirror. The control device CTRL controls the photoelectric conversion device APR, and is, for example, a semiconductor device such as an ASIC. The processing device PRCS processes a signal output from the photoelectric conversion device APR, and constitutes an AFE (analog front end) or a DFE (digital front end). The processing unit PRCS is a semiconductor device such as a central processing unit (CPU) or an application specific integrated circuit (ASIC). The display device DSPL is an EL display device or a liquid crystal display device which displays information (image) obtained by the photoelectric conversion device APR. The storage device MMRY is a magnetic device or a semiconductor device that stores information (images) obtained by the photoelectric conversion device APR. The storage device MMRY is a volatile memory such as an SRAM or a DRAM, or a nonvolatile memory such as a flash memory or a hard disk drive. The machinery device MCHN includes a mobile body or a propulsion unit such as a motor or an engine. In the equipment EQP, a signal output from the photoelectric conversion device APR is displayed on the display device DSPL, and is transmitted to the outside by a communication device (not shown) included in the equipment EQP. Therefore, it is preferable that the equipment EQP further includes the storage device MMRY and the processing device PRCS separately from a storage circuit unit and an arithmetic circuit unit included in the photoelectric conversion device APR

The equipment EQP shown inFIG.13can be an electronic device such as an information terminal (for example, a smartphone or a wearable terminal) having a photographing function or a camera (For example, an interchangeable lens camera, a compact camera, a video camera, and a surveillance camera). The machinery device MCHN in the camera can drive components of the optical device OPT for zooming, focusing, and shutter operation. The equipment EQP may be a transportation device (mobile body) such as a vehicle, a ship, or a flight. The equipment EQP may be a medical device such as an endoscope or a CT scanner. The equipment EQP may be a medical device such as an endoscope or a CT scanner.

The machinery device MCHN in the transport device may be used as a mobile device. The equipment EQP as a transport device is suitable for transporting the photoelectric conversion device APR or for assisting and/or automating operation (manipulation) by an imaging function. The processing device PRCS for assisting and/or automating operation (manipulation) can perform processing for operating the machinery device MCHN as a mobile device based on information obtained by the photoelectric conversion device APR.

The photoelectric conversion device APR according to the present embodiment can provide a designer, a manufacturer, a seller, a purchaser, and/or a user with high value. Therefore, when the photoelectric conversion device APR is mounted on the equipment EQP, the value of the equipment EQP can be increased. Therefore, in order to increase the value of the equipment EQP, it is advantageous to determine the mounting of the photoelectric conversion device APR of the present embodiment on the equipment EQP when the equipment EQP is manufactured and sold.

Other Embodiments

The present invention is not limited to the above embodiments, and various modifications are possible. For example, an example in which some of the configurations of any of the embodiments are added to other embodiments and an example in which some of the configurations of other embodiments are substituted are also embodiments of the present invention.

It should be noted that any of the embodiments described above is merely an example of an embodiment for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited by the embodiments. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2021-198679, filed Dec. 7, 2021, which is hereby incorporated by reference herein in its entirety.