Light detection device and ranging device

Abstract

A light detection device according to an embodiment of the present disclosure comprises: a pixel array which has a plurality of pixels each including a light-receiving element capable of detecting light pulses, in which two or more of the plurality of pixels can be joined together as a light-receiving pixel, and which is capable of generating a detection signal according to light pulse detection timings; a light reception control circuit capable of controlling the operation of the pixel array to switch some of the two or more pixels constituting a light-receiving pixel; and a depth map generation circuit which is capable of generating a first depth map on the basis of a plurality of detection signals generated by a plurality of light-receiving pixels in a case where two or more pixels are first two or more pixels, is capable of generating a second depth map on the basis of a plurality of detection signals in a case where two or more pixels are second two or more pixels, and is capable of generating a composite depth map by performing image compositing processing on the basis of the first depth map and the second depth map.

Description

Light detection and ranging devices

[0001] The present disclosure relates to a light detection device that detects light and a distance measuring device that includes such a light detection device.

[0002] Distance measuring devices often use the ToF (Time Of Flight) method. In this ToF method, light is emitted and the reflected light reflected by the measurement target is detected. The ToF method measures the distance to the measurement target by measuring the time difference between the timing at which the light is emitted and the timing at which the reflected light is detected. For example, Patent Document 1 discloses a distance measuring device that improves resolution by interpolating a distance histogram.

[0003] Japanese Patent Application Laid-Open No. 2021-18123

[0004] In photodetection devices, it is desired to increase the resolution, and further improvements in resolution are expected.

[0005] It is desirable to provide a light detection and ranging device that can provide increased resolution.

[0006] According to an embodiment of the present disclosure, a photodetector device includes a pixel array, a light-receiving control circuit, and a distance image generation circuit. The pixel array includes a plurality of pixels, each of which includes a light-receiving element capable of detecting a light pulse. The pixel array can connect two or more of the pixels as light-receiving pixels, and can generate a detection signal corresponding to the detection timing of the light pulse by performing a light-receiving operation on a light-receiving pixel basis. The light-receiving control circuit can control the operation of the pixel array to switch some of the two or more pixels constituting the light-receiving pixels. The distance image generation circuit can generate a first distance image based on a plurality of detection signals generated by the light-receiving pixels when the two or more pixels are first two or more pixels, and can generate a second distance image based on a plurality of detection signals when the two or more pixels are second two or more pixels, and can generate a composite distance image by performing image synthesis processing on the first distance image and the second distance image.

[0007] A distance measuring device according to an embodiment of the present disclosure includes a light source, a pixel array, a light-receiving control circuit, and a distance image generation circuit. The light source is capable of emitting a first light pulse. The pixel array has a plurality of pixels. Each of the plurality of pixels includes a light-receiving element capable of detecting a second light pulse in response to the first light pulse. The pixel array can connect two or more of the plurality of pixels as light-receiving pixels, and can generate a detection signal in response to the detection timing of the second light pulse by performing a light-receiving operation on a light-receiving pixel basis. The light-receiving control circuit can control the operation of the pixel array to switch some of the two or more pixels constituting the light-receiving pixels. The distance image generation circuit can generate a first distance image based on a plurality of detection signals generated by the plurality of light-receiving pixels when the two or more pixels are first two or more pixels, and can generate a second distance image based on a plurality of detection signals when the two or more pixels are second two or more pixels, and can generate a composite distance image by performing image synthesis processing on the first distance image and the second distance image.

[0008] In a light detection device according to an embodiment of the present disclosure, a pixel detects a light pulse. Two or more pixels among a plurality of pixels in a pixel array are connected as a light-receiving pixel. The pixel array performs a light-receiving operation for each light-receiving pixel, and generates a detection signal according to the timing of the detection of the light pulse. The pixel array is controlled by a light-receiving control circuit to switch some of the two or more pixels constituting the light-receiving pixel. The distance image generation circuit generates a first distance image based on a plurality of detection signals generated by the plurality of light-receiving pixels when the two or more pixels are first two or more pixels, and generates a second distance image based on a plurality of detection signals when the two or more pixels are second two or more pixels. The distance image generation circuit then performs an image synthesis process based on the first distance image and the second distance image, thereby generating a synthetic distance image.

[0009] In a distance measuring device according to an embodiment of the present disclosure, a light source emits a first light pulse, and a pixel detects a second light pulse corresponding to the first light pulse. Two or more pixels among a plurality of pixels in a pixel array are connected as light-receiving pixels. The pixel array performs a light-receiving operation for each light-receiving pixel, and generates a detection signal corresponding to the timing of the detection of the light pulse. The pixel array is controlled by a light-receiving control circuit to switch some of the two or more pixels constituting the light-receiving pixels. The distance image generation circuit generates a first distance image based on multiple detection signals generated by the multiple light-receiving pixels when the two or more pixels are the first two or more pixels, and generates a second distance image based on multiple detection signals when the two or more pixels are the second two or more pixels. The distance image generation circuit then performs image synthesis processing based on the first distance image and the second distance image, thereby generating a synthetic distance image.

[0010] FIG. 1 is a block diagram illustrating an example configuration of a distance measuring device according to an embodiment of the present disclosure. FIG. 2 is a block diagram illustrating an example configuration of a photodetector shown in FIG. 1. FIG. 3 is a circuit diagram illustrating an example configuration of a pixel shown in FIG. 2. FIG. 4 is a timing waveform diagram illustrating an example operation of the pixel shown in FIG. 3. FIG. 5 is an explanatory diagram illustrating an example configuration of a plurality of pixels in the pixel array shown in FIG. 2. FIG. 6 is an explanatory diagram illustrating an example operation of a plurality of pixels shown in FIG. 5. FIG. 7 is an explanatory diagram illustrating an example configuration of the pixel array shown in FIG. 2. FIG. 8 is another explanatory diagram illustrating an example configuration of the pixel array shown in FIG. 2. FIG. 9 is an explanatory diagram illustrating an example connection between the pixel array shown in FIG. 2 and a TDC unit. FIG. 10 is an explanatory diagram illustrating an implementation example of the photodetector shown in FIG. 2. FIG. 11 is an explanatory diagram illustrating another implementation example of the photodetector shown in FIG. 2. FIG. 12 is an explanatory diagram illustrating another implementation example of the photodetector shown in FIG. 2. FIG. 13 is a flowchart illustrating an example operation of the distance measuring device shown in FIG. 1. FIG. 14 is an explanatory diagram illustrating an example operation of the pixel array shown in FIG. 2. FIG. 15 is an explanatory diagram showing an example of the operation of image synthesis processing in the distance image generation unit shown in FIG. 2. FIG. 16 is an explanatory diagram showing an example of the operation of the distance measuring device shown in FIG. 1. FIG. 16 is another explanatory diagram showing an example of the operation of the distance measuring device shown in FIG. 1. FIG. 18 is an explanatory diagram showing an example of the configuration of multiple pixels in a pixel array according to a modified example. FIG. 19 is an explanatory diagram showing an example of the operation of the multiple pixels shown in FIG. 18. FIG. 20 is an explanatory diagram showing an example of the configuration of multiple pixels in a pixel array according to another modified example. FIG. 21 is an explanatory diagram showing an example of the operation of the multiple pixels shown in FIG. 20. FIG. 22 is an explanatory diagram showing an example of the configuration of multiple pixels in a pixel array according to another modified example. FIG. 23 is an explanatory diagram showing an example of the operation of the multiple pixels shown in FIG. 22. FIG. 24 is a flowchart showing an example of the operation of the distance measuring device according to another modified example. FIG. 25 is an explanatory diagram showing an example of the operation of the distance measuring device shown in FIG. 24. FIG. 26 is an explanatory diagram showing an example of the configuration of a pixel array according to another modified example. FIG. 27 is an explanatory diagram showing an example of the configuration of a pixel array according to another modified example. Fig. 28 is an explanatory diagram showing an example of the operation of an imaging device according to another modified example Fig. 29 is a block diagram showing an example of a schematic configuration of a vehicle control system.FIG. 30 is an explanatory diagram showing an example of the installation position of the imaging unit.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order: 1. Embodiment 2. Application to a moving body

[0012] 1 shows an example of the configuration of a distance measuring device 1 equipped with a light detection device according to an embodiment. The distance measuring device 1 is a ToF sensor configured to emit light toward a measurement target and detect light reflected by the measurement target. The distance measuring device 1 includes a light emitting unit 11, an optical system 12, a light detecting unit 20, and a control unit 14.

[0013] The light emitting unit 11 is configured to emit a light pulse L0 toward the measurement target based on instructions from the control unit 14. The light emitting unit 11 emits the light pulse L0 by performing a light emitting operation that alternately repeats light emission and non-emission based on instructions from the control unit 14. The light emitting unit 11 has a light source that emits, for example, infrared light. This light source is configured using, for example, a laser light source.

[0014] The optical system 12 (FIG. 1) includes a lens that forms an image on the light receiving surface S of the light detection unit 20. A light pulse (reflected light pulse L1) that is emitted from the light emitting unit 11 and reflected by the measurement object is incident on this optical system 12.

[0015] The light detection unit 20 is configured to detect the reflected light pulse L1 based on instructions from the control unit 14. The light detection unit 20 then generates a distance image based on the detection result and outputs image data of the generated distance image as data DT.

[0016] The control unit 14 is configured to control the operation of the distance measuring device 1 by supplying control signals to the light emitting unit 11 and the light detecting unit 20 and controlling their operations.

[0017] With this configuration, the distance measuring device 1 repeatedly emits light pulses L0 and repeatedly detects reflected light pulses L1 corresponding to the light pulses L0, thereby generating a histogram of ToF values, and then the distance measuring device 1 detects the distance to the measurement target based on the histogram.

[0018] 2 shows an example of the configuration of the light detection unit 20. The light detection unit 20 includes a pixel array 21, a TDC (Time to Digital Converter) unit 22, a histogram generation unit 23, a distance image generation unit 24, and a distance measurement control unit 25.

[0019] The pixel array 21 has a plurality of pixels P arranged in a matrix. Each of the plurality of pixels P is configured to generate a pulse signal PLS1 by detecting a reflected light pulse L1.

[0020] 3 shows an example of the configuration of the pixel P. The pixel P has a photodiode PD, a current source CS1, and an inverter IV1.

[0021] The photodiode PD is a photoelectric conversion element that converts light into an electric charge. A bias voltage VA is supplied to the anode of the photodiode PD, and the cathode is connected to a node N1. The photodiode PD may be, for example, a single photon avalanche diode (SPAD).

[0022] The current source CS1 is configured to pass a predetermined current from the power supply node of the power supply voltage VDD toward the node N1.

[0023] The inverter IV1 is configured to generate the pulse signal PLS1 by outputting a low level when the voltage at the node N1 is higher than the logical threshold voltage Vth and outputting a high level when the voltage at the node N1 is lower than the logical threshold voltage Vth.

[0024] FIG. 4 shows an example of the operation of pixel P, where (A) shows the waveform of the voltage (voltage VN1) at node N1, and (B) shows the waveform of pulse signal PLS1.

[0025] When the reflected light pulse L1 is incident on the photodiode PD, a current flows from the cathode to the anode of the photodiode PD, and at timing t1, the voltage VN1 at the node N1 starts to decrease from the power supply voltage VDD (FIG. 4A). Then, at timing t2, when the voltage VN1 falls below the logical threshold voltage Vth, the inverter IV1 changes the pulse signal PLS1 from low to high (FIG. 4B).

[0026] The voltage VN1 at the node N1 drops to a certain level and then starts to rise, exceeding the logical threshold voltage Vth at timing t3 (FIG. 4A). This causes the inverter IV1 to change the pulse signal PLS1 from high to low (FIG. 4B). Thereafter, the voltage VN1 returns to the power supply voltage VDD.

[0027] In this way, the pixel P generates a pulse signal PLS1 by detecting the reflected light pulse L1.

[0028] 5 shows an example of the arrangement of multiple pixels P in the pixel array 21. In the pixel array 21, units U each including four pixels P are repeatedly arranged. The four pixels P included in the unit U are arranged in two rows and two columns. These four pixels P include one pixel P1 and three pixels P2. In this example, in the unit U, pixel P1 is arranged in the lower right, and three pixels P2 are arranged in the upper left, upper right, and lower left, respectively. In this FIG. 5, the shaded pixels P indicate pixel P1, and the unshaded pixels P indicate pixel P2.

[0029] 6A to 6D show an example of the operation of the pixel array 21. Each of Fig. 6A to 6D shows nine pixels P arranged in three rows and three columns, with pixel P1 at the center.

[0030] In the pixel array 21, four pixels P are connected to form one light-receiving pixel PP, and the reflected light pulse L1 is detected for each light-receiving pixel PP. The four pixels P that make up this light-receiving pixel PP are arranged in two rows and two columns and can be switched. Specifically, in FIG. 6A , of the nine pixels P, the four upper left pixels P make up the light-receiving pixel PP; in FIG. 6B , of the nine pixels P, the four upper right pixels P make up the light-receiving pixel PP; in FIG. 6C , of the nine pixels P, the four lower right pixels P make up the light-receiving pixel PP; and in FIG. 6D , of the nine pixels P, the four lower left pixels P make up the light-receiving pixel PP. Because the four pixels P that make up the light-receiving pixel PP are arranged in two rows and two columns, the light-receiving region of the light-receiving pixel PP is a rectangular region. In the pixel array 21, as shown in FIGS. 6A to 6D, the four pixels P that make up the light-receiving pixel PP can be switched in a time-division manner.

[0031] 7 and 8 show an example configuration of a portion of the pixel array 21 relating to the nine pixels P shown in FIG. 6. As shown in FIG. 7, the pixel array 21 has a connection unit 29. The connection unit 29 is configured to generate a pulse signal PLS by connecting four of the nine pixels P (one pixel P1 and eight pixels P2). The connection unit 29 has eight AND circuits AN1 to AN8, a logical OR circuit OR1, and a tri-state buffer BUF1.

[0032] As shown in FIG. 8 , the eight AND circuits AN1 to AN8 are provided corresponding to the eight pixels P2 surrounding pixel P1. The AND circuit AN1 corresponds to pixel P2 located to the upper left of pixel P1. The AND circuit AN1 receives a pulse signal PLS1 supplied from pixel P2 corresponding to the AND circuit AN1 at its first input terminal, a control signal SEL1 at its second input terminal, and an output terminal connected to the OR circuit OR1. The AND circuit AN2 corresponds to pixel P2 located above pixel P1. The AND circuit AN2 receives a pulse signal PLS1 supplied from pixel P2 corresponding to the AND circuit AN2 at its first input terminal, a control signal SEL2 at its second input terminal, and an output terminal connected to the OR circuit OR1. The AND circuit AN3 corresponds to pixel P2 located to the upper right of pixel P1. The AND circuit AN3 has a first input terminal that receives the pulse signal PLS1 from the pixel P2 corresponding to the AND circuit AN3, a second input terminal that receives the control signal SEL3, and an output terminal that is connected to the OR circuit OR1. The AND circuit AN4 corresponds to the pixel P2 located to the left of the pixel P1. The AND circuit AN4 has a first input terminal that receives the pulse signal PLS1 from the pixel P2 corresponding to the AND circuit AN4, a second input terminal that receives the control signal SEL4, and an output terminal that is connected to the OR circuit OR1. The AND circuit AN5 corresponds to the pixel P2 located to the right of the pixel P1. The AND circuit AN5 has a first input terminal that receives the pulse signal PLS1 from the pixel P2 corresponding to the AND circuit AN5, a second input terminal that receives the control signal SEL5, and an output terminal that is connected to the OR circuit OR1. The AND circuit AN6 corresponds to the pixel P2 located to the lower left of the pixel P1. The AND circuit AN6 has a first input terminal that receives the pulse signal PLS1 supplied from the pixel P2 corresponding to the AND circuit AN6, a second input terminal that receives the control signal SEL6, and an output terminal that is connected to the OR circuit OR1. The AND circuit AN7 corresponds to the pixel P2 provided below the pixel P1. The AND circuit AN7 has a first input terminal that receives the pulse signal PLS1 supplied from the pixel P2 corresponding to the AND circuit AN7, a second input terminal that receives the control signal SEL7, and an output terminal that is connected to the OR circuit OR1.The logical product circuit AN8 corresponds to pixel P2 located to the lower right of pixel P1. The pulse signal PLS1 supplied from pixel P2 corresponding to the logical product circuit AN8 is input to a first input terminal of the logical product circuit AN8, the control signal SEL8 is input to a second input terminal of the logical product circuit AN8, and the output terminal is connected to the logical sum circuit OR1.

[0033] The OR circuit OR1 is a nine-input OR circuit, and has a first input terminal to which the pulse signal PLS1 supplied from the pixel P1 is input, and a second input terminal to a ninth input terminal to which the pulse signals supplied from the AND circuits AN1 to AN8 are input, respectively. The OR circuit OR1 generates the pulse signal PLS by calculating the logical sum based on these nine pulse signals.

[0034] The tri-state buffer BUF1 is configured to output the input pulse signal PLS or set the output impedance to high impedance based on the control signal CTL. The input terminal of the tri-state buffer BUF1 is connected to the output terminal of the OR circuit OR1, and the output terminal is connected to the signal line SGL (FIG. 8). As shown in FIG. 9, the output terminals of a plurality of tri-state buffers BUF1 are connected to this signal line SGL. In this example, in the horizontal direction of FIG. 9, a plurality of tri-state buffers BUF1 are connected to one signal line SGL at a ratio of one for every four tri-state buffers BUF1. However, this is not limiting. For example, a plurality of tri-state buffers BUF1 may be connected to one signal line SGL at a ratio of one for every two or three tri-state buffers BUF1, or a plurality of tri-state buffers BUF1 may be connected to one signal line SGL at a ratio of one for every five or more tri-state buffers BUF1.

[0035] In the connecting unit 29, three of the eight control signals SEL1 to SEL8 supplied to the eight AND circuits AN1 to AN8 are set to a high level, and the remaining five are set to a low level. As a result, the pulse signal PLS1 supplied from pixel P1 and three pulse signals PLS1 supplied from three of the eight pixels P2 are essentially input to the OR circuit OR1. The OR circuit OR1 generates a pulse signal PLS based on the four pulse signals PLS1 supplied from these four pixels P. In this way, the connecting unit 29 can connect four of the nine pixels P based on the eight control signals SEL1 to SEL8.

[0036] Specifically, in Fig. 8, when the control signals SEL1, SEL2, and SEL4 are at high levels, the connection unit 29 can connect the four upper left pixels P of the nine pixels P as shown in Fig. 6(A). When the control signals SEL2, SEL3, and SEL5 are at high levels, the connection unit 29 can connect the four upper right pixels P of the nine pixels P as shown in Fig. 6(B). When the control signals SEL5, SEL7, and SEL8 are at high levels, the connection unit 29 can connect the four lower right pixels P of the nine pixels P as shown in Fig. 6(C). When the control signals SEL4, SEL6, and SEL7 are at high levels, the connection unit 29 can connect the four lower left pixels P of the nine pixels P as shown in Fig. 6(D).

[0037] The TDC unit 22 (FIG. 2) is configured to generate a timing code corresponding to the detection timing of the reflected light pulse L1 at the light-receiving pixel PP, based on the pulse signal PLS supplied from the pixel array 21.

[0038] The histogram generating section 23 is configured to generate a histogram of the detection timing of the reflected light pulse L1 at the light receiving pixel PP based on the timing code generated by the TDC section 22.

[0039] The distance image generation unit 24 is configured to generate a distance image PIC by calculating the distance between the distance measuring device 1 and the measurement target based on the histogram generated by the histogram generation unit 23. Specifically, as shown in FIG. 6A, when the four upper left pixels P of the nine pixels P constitute light-receiving pixels PP, the distance image generation unit 24 generates a distance image PIC0 based on the histogram. Similarly, as shown in FIG. 6B, when the four upper right pixels P of the nine pixels P constitute light-receiving pixels PP, the distance image generation unit 24 generates a distance image PIC1 based on the histogram. As shown in FIG. 6C, when the four lower right pixels P of the nine pixels P constitute light-receiving pixels PP, the distance image generation unit 24 generates a distance image PIC2 based on the histogram. As shown in FIG. 6D, when the four lower left pixels P of the nine pixels P constitute light-receiving pixels PP, the distance image generation unit 24 generates a distance image PIC3 based on the histogram. The distance image generator 24 then performs image synthesis processing based on these four distance images PIC0 to PIC3 to generate the distance image PIC, and outputs the image data of the generated distance image PIC as data DT.

[0040] The ranging control unit 25 is configured to control the operations of the pixel array 21, the TDC unit 22, the histogram generation unit 23, and the distance image generation unit 24 based on instructions from the control unit 14 (FIG. 1). The ranging control unit 25 controls the operation of the pixel array 21 by supplying control signals SEL1 to SEL8 and a control signal CTL to the pixel array 21. The ranging control unit 25 uses the control signals SEL1 to SEL8 to control the pixel array 21 so as to switch some of the four pixels that make up the light-receiving pixel PP.

[0041] The photodetector 20 (FIG. 2) may be formed on one semiconductor substrate or on multiple semiconductor substrates, as will be described in detail below with reference to several examples.

[0042] 10 shows an example implementation of the photodetector unit 20. In this example, the photodetector unit 20 is formed on a single semiconductor substrate 101. Regions R21 and R27 are provided on the semiconductor substrate 101. In region R21, the photodiode PD of the pixel array 21 of the photodetector unit 20, the current source CS1, the inverter IV1, and the connecting unit 29 are formed. In region R27, the TDC unit 22, the histogram generator 23, the distance image generator 24, and the distance measurement controller 25 are formed.

[0043] FIG. 11 shows another implementation example of the photodetector unit 20. In this example, the photodetector unit 20 is formed on two semiconductor substrates 111 and 112. The semiconductor substrate 111 is disposed on the light-receiving surface S side of the photodetector unit 20, and the semiconductor substrate 112 is disposed on the opposite side of the light-receiving surface S of the photodetector unit 20. The semiconductor substrates 111 and 112 are overlapped with each other. A region R21A is provided in the semiconductor substrate 111, and a region R21B and a region R27 are provided in the semiconductor substrate 112. The region R21A in the semiconductor substrate 111 and the region R21B in the semiconductor substrate 112 correspond to each other. The photodiode PD of the pixel array 21 is disposed in the region R21A in the semiconductor substrate 111, and the current source CS1, inverter IV1, and connecting unit 29 of the pixel array 21 are disposed in the region R21B in the semiconductor substrate 112. That is, pixel array 21 is disposed across two semiconductor substrates 111 and 112. TDC unit 22, histogram generation unit 23, distance image generation unit 24, and distance measurement control unit 25 are disposed in region R27 of semiconductor substrate 112. The wiring of semiconductor substrate 111 and the wiring of semiconductor substrate 112 are connected by metal bonding, for example, Cu-Cu bonding or bump bonding.

[0044] FIG. 12 shows another implementation example of the photodetector 20. In this example, the photodetector 20 is formed on three semiconductor substrates 121, 122, and 123. The semiconductor substrate 121 is disposed on the light-receiving surface S side of the photodetector 20, the semiconductor substrate 122 is disposed second from the light-receiving surface S side of the photodetector 20, and the semiconductor substrate 123 is disposed on the opposite side of the light-receiving surface S of the photodetector 20. The semiconductor substrates 121 and 122 are overlapped with each other, and the semiconductor substrates 122 and 123 are overlapped with each other. The semiconductor substrate 121 is provided with a region R21C, the semiconductor substrate 122 is provided with a region R21D, and the semiconductor substrate 123 is provided with regions R21E and R27. The region R21C in the semiconductor substrate 121, the region R21D in the semiconductor substrate 122, and the region R21E in the semiconductor substrate 123 correspond to each other. The photodiodes PD of the pixel array 21 are arranged in a region R21C of the semiconductor substrate 121, the current source CS1 and inverter IV1 of the pixel array 21 are arranged in a region R21D of the semiconductor substrate 122, and the connecting unit 29 is arranged in a region R21E of the semiconductor substrate 123. That is, the pixel array 21 is arranged across the three semiconductor substrates 121 to 123. The TDC unit 22, the histogram generator 23, the distance image generator 24, and the distance measurement controller 25 are arranged in a region R27 of the semiconductor substrate 123. The wiring of the semiconductor substrate 121 and the wiring of the semiconductor substrate 122 are connected by metal bonding, such as Cu-Cu bonding, bump bonding, or through-vias, and similarly, the wiring of the semiconductor substrate 122 and the wiring of the semiconductor substrate 123 are connected by metal bonding, such as Cu-Cu bonding, bump bonding, or through-vias.

[0045] Here, the pixel array 21 corresponds to a specific example of a "pixel array" in an embodiment of the present disclosure. The photodiode PD corresponds to a specific example of a "light receiving element" in an embodiment of the present disclosure. The inverter IV1 corresponds to a specific example of a "pulse generating circuit" in an embodiment of the present disclosure. The connecting unit 29 corresponds to a specific example of a "connecting circuit" in an embodiment of the present disclosure. The pixel P corresponds to a specific example of a "pixel" in an embodiment of the present disclosure. The light receiving pixel PP corresponds to a specific example of a "light receiving pixel" in an embodiment of the present disclosure. The pulse signal PLS corresponds to a specific example of a "detection signal" in an embodiment of the present disclosure. The ranging control unit 25 corresponds to a specific example of a "light receiving control circuit" in an embodiment of the present disclosure. The TDC unit 22, the histogram generation unit 23, and the distance image generation unit 24 correspond to a specific example of a "distance image generation circuit" in an embodiment of the present disclosure. The distance image PIC0 corresponds to a specific example of a "first distance image" in an embodiment of the present disclosure. Distance image PIC1 corresponds to a specific example of a "second distance image" in an embodiment of the present disclosure. Distance image PIC2 corresponds to a specific example of a "third distance image" in an embodiment of the present disclosure. Distance image PIC3 corresponds to a specific example of a "fourth distance image" in an embodiment of the present disclosure. Signal line SGL corresponds to a specific example of a "signal line" in an embodiment of the present disclosure.

[0046] [Operation and Function] Next, the operation and function of the distance measuring device 1 of this embodiment will be described.

[0047] (Overall Operation Overview) First, an overview of the overall operation of the distance measuring device 1 will be described with reference to Figures 1 and 3. The light emitting unit 11 emits a light pulse L0 toward the measurement target. The optical system 12 forms an image on the light receiving surface S of the light detecting unit 20. The light detecting unit 20 detects the reflected light pulse L1. The control unit 14 supplies control signals to the light emitting unit 11 and the light detecting unit 20 and controls their operations, thereby controlling the distance measuring operation of the distance measuring device 1.

[0048] In the light detection unit 20, the pixels P of the pixel array 21 detect the reflected light pulse L1 and generate a pulse signal PLS1. The connection unit 29 generates a pulse signal PLS by connecting four of the nine pixels P based on eight control signals SEL1 to SEL8. These four pixels P constitute a light-receiving pixel PP. The TDC unit 22 generates a timing code corresponding to the detection timing of the reflected light pulse L1 at the light-receiving pixel PP based on the pulse signal PLS supplied from the pixel array 21. The histogram generation unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at the light-receiving pixel PP based on the timing code generated by the TDC unit 22. The distance image generation unit 24 generates a distance image PIC by calculating the distance between the distance measuring device 1 and the measurement target based on the histogram generated by the histogram generation unit 23. The distance image generation unit 24 then outputs image data of the generated distance image PIC as data DT. Based on instructions from the control unit 14, the ranging control unit 25 controls the operations of the pixel array 21, the TDC unit 22, the histogram generation unit 23, and the distance image generation unit 24. Using control signals SEL1 to SEL8, the ranging control unit 25 controls the pixel array 21 to switch some of the four pixels that make up the light-receiving pixel PP.

[0049] (Detailed Operation) FIG. 13 shows an example of the operation of the distance measuring device 1.

[0050] First, the control unit 14 sets a variable N to 0 (N=0) (step S101).

[0051] Next, the connecting unit 29 connects the four pixels P according to the variable N (step S102). Specifically, the ranging control unit 25 generates control signals SEL1 to SEL8 based on an instruction from the control unit 14. The connecting unit 29 connects the four pixels P based on these control signals SEL1 to SEL8.

[0052] For example, when the variable N is 0, the ranging control unit 25 generates control signals SEL1 to SEL8 so as to connect the four upper left pixels P of the nine pixels P, as shown in Fig. 6A. The connecting unit 29 connects the four upper left pixels P based on the control signals SEL1 to SEL8. As a result, the four upper left pixels P constitute the light-receiving pixel PP.

[0053] For example, when the variable N is 1, the ranging control unit 25 generates control signals SEL1 to SEL8 so as to connect the four upper right pixels P of the nine pixels P, as shown in FIG. 6B. The connecting unit 29 connects the four upper right pixels P based on the control signals SEL1 to SEL8. As a result, the four upper right pixels P constitute the light receiving pixel PP.

[0054] For example, when the variable N is 2, the ranging control unit 25 generates control signals SEL1 to SEL8 so as to connect the four pixels P at the bottom right of the nine pixels P, as shown in Fig. 6C. The connecting unit 29 connects these four pixels P at the bottom right based on the control signals SEL1 to SEL8. As a result, these four pixels P at the bottom right constitute the light-receiving pixel PP.

[0055] For example, when the variable N is 3, the ranging control unit 25 generates control signals SEL1 to SEL8 so as to connect the four bottom left pixels P of the nine pixels P, as shown in Fig. 6(D). The connecting unit 29 connects the four bottom left pixels P based on the control signals SEL1 to SEL8. As a result, the four bottom left pixels P constitute the light receiving pixel PP.

[0056] Next, the distance measuring device 1 performs a distance measurement operation (step S103). Specifically, the light emitting unit 11 emits a light pulse L0 by alternately repeating light emission and non-emission based on instructions from the control unit 14. In the pixel array 21, four pixels P constituting a light receiving pixel PP detect a reflected light pulse L1 to generate a pulse signal PLS1. The connecting unit 29 generates a pulse signal PLS based on the pulse signals PLS1 supplied from these four pixels P. Based on this pulse signal PLS, the TDC unit 22 generates a timing code corresponding to the detection timing of the reflected light pulse L1 at the light receiving pixel PP. Based on the timing code generated by the TDC unit 22, the histogram generating unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at the light receiving pixel PP.

[0057] Next, the distance image generation unit 24 generates a distance image (step S104). Specifically, the distance image generation unit 24 calculates, for example, a detection timing corresponding to the mode based on the histogram generated by the histogram generation unit 23, and calculates a distance value based on this detection timing. The distance image generation unit 24 calculates the distance value based on the histograms associated with each of the multiple light-receiving pixels PP. In this manner, the distance image generation unit 24 generates a distance image. Specifically, the distance image generation unit 24 generates a distance image PIC0 when the variable N is 0, a distance image PIC1 when the variable N is 1, a distance image PIC2 when the variable N is 2, and a distance image PIC3 when the variable N is 3.

[0058] Next, the control unit 14 checks whether the variable N is less than 4 (N<4) (step S105). If the variable N is less than 4 ("Y" in step S105), the control unit 14 increments the variable N (step S106). Then, the process returns to step S102. The distance measuring device 1 repeats the processes of steps S102 to S106 until the variable N becomes 4 or greater. As a result, the distance measuring device 1 generates a distance image PIC0 when the four upper left pixels P constitute the light-receiving pixels PP as shown in FIG. 6A, a distance image PIC1 when the four upper right pixels P constitute the light-receiving pixels PP as shown in FIG. 6B, a distance image PIC2 when the four lower right pixels P constitute the light-receiving pixels PP as shown in FIG. 6C, and a distance image PIC3 when the four upper left pixels P constitute the light-receiving pixels PP as shown in FIG. 6D.

[0059] In step S105, if the variable N is 4 or greater ("N" in step S105), the distance image generating unit 24 generates the distance image PIC by performing image synthesis processing based on the four distance images PIC0 to PIC3.

[0060] 14 shows an example of the operation of the pixel array 21, where (A) shows the case where the variable N is 0 (N=0), (B) shows the case where the variable N is 1 (N=1), (C) shows the case where the variable N is 2 (N=2), and (D) shows the case where the variable N is 3 (N=3). Four pixels P surrounded by solid lines constitute the light-receiving pixels PP. Also, in FIG. 14, nine pixels P arranged in three rows and three columns, including pixel P1 at the center, are shown by dashed dotted lines.

[0061] When the variable N is 0, as shown in Figure 14A, the four upper left pixels P of the nine pixels P constitute the light-receiving pixel PP, and a distance value is obtained for this light-receiving pixel PP. The center of gravity of these four pixels P is (0.5, 0.5). The first value indicates the horizontal position, and the second value indicates the vertical position.

[0062] When the variable N is 1, as shown in FIG. 14B, the four upper right pixels P of the nine pixels P constitute a light-receiving pixel PP, and a distance value is obtained for this light-receiving pixel PP. The center of gravity of these four pixels P is (1.5, 0.5). In other words, this center of gravity position is shifted to the right from the center of gravity position shown in FIG. 14A by a distance corresponding to one pixel P, so the center of gravity position is (1.5, 0.5).

[0063] When the variable N is 2, as shown in Figure 14(C), the four pixels P at the bottom right of the nine pixels P constitute a light-receiving pixel PP, and a distance value is obtained for this light-receiving pixel PP. The center of gravity of these four pixels P is (1.5, 1.5). In other words, this center of gravity position is shifted downward from the center of gravity position shown in Figure 14(B) by the distance corresponding to one pixel P, so the center of gravity position is (1.5, 1.5).

[0064] When the variable N is 3, as shown in Fig. 14(D), the four pixels P at the bottom left of the nine pixels P constitute a light-receiving pixel PP, and a distance value is obtained for this light-receiving pixel PP. The center of gravity of these four pixels P is (0.5, 1.5). In other words, this center of gravity position is shifted to the left from the center of gravity position shown in Fig. 14(C) by the distance corresponding to one pixel P, so the center of gravity position is (0.5, 1.5).

[0065] In this way, the centers of gravity of the light-receiving pixels PP are shifted from one another. Therefore, the distance image generator 24 generates the distance image PIC by performing image synthesis processing based on the four distance images PIC0 to PIC3, taking this shift in center of gravity into consideration.

[0066] Figure 15 shows an example of image synthesis processing, where (A) shows distance image PIC0, (B) shows distance image PIC1, (C) shows distance image PIC2, ​​(D) shows distance image PIC3, and (E) shows distance image PIC.

[0067] 15A to 15D, in distance images PIC0 to PIC3, the distance value obtained based on the light-receiving result of a light-receiving pixel PP is the value at the center of gravity of the four pixels P that make up that light-receiving pixel PP. Therefore, distance image generator 24 generates distance image PIC shown in FIG. 15E by arranging each of the multiple distance values ​​in distance images PIC0 to PIC3 at the center of gravity of the four pixels P associated with that distance value.

[0068] In this way, the distance image generating unit 24 generates the distance image PIC by performing image synthesis processing based on the four distance images PIC0 to PIC3.

[0069] This is the end of this flow.

[0070] In this way, the distance measuring device 1 generates distance images PIC0 to PIC3 using each light-receiving pixel PP as a unit while switching between the four pixels P that make up the light-receiving pixel PP. The distance measuring device 1 then generates the distance image PIC by performing image synthesis processing based on these four distance images PIC0 to PIC3.

[0071] For example, when the variable N is 0, the four upper left pixels P of the nine pixels P constitute the light-receiving pixel PP, as shown in Figure 14(A), and when the variable N is 1, the four upper right pixels P of the nine pixels P constitute the light-receiving pixel PP, as shown in Figure 14(B).

[0072] 16A and 16B show specific examples of distance measurement operations, in which (A) shows an example of distance measurement operation when the variable N is 0, and (B) shows an example of distance measurement operation when the variable N is 1. In this example, a person 92 is standing in front of a door 91. The distance measuring device 1 measures the distance to the door 91 and the person 92. In FIG. 16A, the light-receiving pixel PP detects a reflected light pulse L1 from the door 91. In FIG. 16B, the position of the light-receiving pixel PP is shifted to the right by one pixel P compared to the case in FIG. 16A, so the light-receiving pixel PP detects reflected light pulses L1 from both the door 91 and the person 92.

[0073] Fig. 17 shows an example of a histogram related to the light-receiving pixel PP shown in Fig. 16. The characteristic W0 indicates the case where the variable N is 0, and the characteristic W1 indicates the case where the variable N is 1.

[0074] When the variable N is 0, as shown in Figure 16 (A), the light receiving pixel PP detects the reflected light pulse L1 from the door 91, so that the frequency value becomes high at the detection timing corresponding to the distance from the distance measuring device 1 to the door 91, as shown in characteristic W0.

[0075] On the other hand, when the variable N is 1, as shown in Figure 16 (B), the light receiving pixel PP detects reflected light pulses L1 from both the door 91 and the person 92, so as shown in characteristic W1, the frequency value is high at the detection timing corresponding to the distance from the ranging device 1 to the door 91 and at the detection timing corresponding to the distance from the ranging device 1 to the person 92.

[0076] As shown in FIG. 16B, each light-receiving pixel PP can separately detect reflected light pulses L1 from multiple measurement targets at different distances. As shown by characteristic W1 in FIG. 17, these distance values ​​do not mix, so even when distance measurement is performed using a light-receiving pixel PP that includes four pixels P, resolution does not decrease. For example, if pixels were connected in a similar manner in an image sensor, the resolution would become coarse, resulting in a blurred image. On the other hand, in the distance measuring device 1, distance values ​​obtained from a single light-receiving pixel PP do not mix, so resolution does not decrease. Furthermore, in the distance measuring device 1, the distance image PIC is generated by performing image synthesis processing based on the four distance images PIC0 to PIC3 for each light-receiving pixel PP, thereby increasing resolution.

[0077] In this way, the light detection unit 20 has a plurality of pixels P, each including a light receiving element (photodiode PD) capable of detecting a light pulse, and four pixels P of the plurality of pixels P can be connected as a light receiving pixel PP, and the pixel array 21 can generate a detection signal (pulse signal PLS) according to the detection timing of the light pulse by performing a light receiving operation in units of the light receiving pixel PP, a light receiving control circuit (distance measurement control unit 25) can control the operation of the pixel array 21 to switch some of the four pixels P that make up the light receiving pixel PP, and when the four pixels P are first four pixels P (for example, the four pixels P in the upper left corner shown in Figure 6 (A)), The optical detection unit 20 is provided with a distance image generation circuit (TDC unit 22, histogram generation unit 23, and distance image generation unit 24) that can generate a first distance image (e.g., distance image PIC0) based on multiple detection signals (pulse signals PLS) generated by multiple light-receiving pixels PP, generate a second distance image (e.g., distance image PIC1) based on multiple detection signals (pulse signals PLS) when the four pixels P are the second four pixels P (e.g., the four upper right pixels P shown in Figure 6 (B)), and generate a composite distance image (distance image PIC) by performing image synthesis processing based on the first distance image and the second distance image. This allows the optical detection unit 20 to increase its resolution.

[0078] That is, for example, if multiple pixels P were connected to signal lines SGL without providing connecting portions 29, the number of signal lines SGL would increase, making it difficult to arrange multiple signal lines SGL. Therefore, the arrangement density of pixels P may be limited by the number of signal lines SGL that can be arranged. In other words, the resolution may be limited by the number of signal lines SGL that can be arranged. In the photodetection unit 20, the connecting portions 29 are provided, allowing four of the multiple pixels P to be connected as light-receiving pixels PP, so the number of signal lines SGL can be reduced. As a result, the arrangement density of pixels P can be increased in the photodetection unit 20. Furthermore, in the photodetection unit 20, image synthesis processing is performed based on distance images PIC0 to PIC3 that are based on light-receiving pixels PP, thereby improving resolution.

[0079] Furthermore, in the photodetector unit 20, the multiple pixels P include a first pixel, a second pixel, and a third pixel (for example, in FIG. 6, three pixels P arranged in the horizontal direction including pixel P1 in the center), the first pixel, the second pixel, and the third pixel are arranged in this order in the first direction, the first four pixels (for example, the four pixels P in the upper left shown in FIG. 6A) include the first pixel and the second pixel, and the second four pixels (for example, the four pixels P in the upper right shown in FIG. 6B) include the second pixel and the third pixel. This allows the photodetector unit 20 to reduce the number of signal lines SGL, thereby increasing the resolution.

[0080] [Effect] As described above, in this embodiment, there is provided a pixel array having a plurality of pixels, each including a light-receiving element capable of detecting light pulses, in which four of the plurality of pixels can be connected as a light-receiving pixel, and in which a detection signal corresponding to the detection timing of the light pulse can be generated by performing a light-receiving operation on a unit basis of the light-receiving pixel; a light-receiving control circuit capable of controlling the operation of the pixel array to switch some of the four pixels that constitute the light-receiving pixel; and a distance image generation circuit capable of generating a first distance image based on a plurality of detection signals generated by the plurality of light-receiving pixels when the four pixels are first four pixels, and capable of generating a second distance image based on a plurality of detection signals when the four pixels are second four pixels, and capable of generating a composite distance image by performing image synthesis processing based on the first distance image and the second distance image, thereby enabling improvement of resolution.

[0081] In this embodiment, the plurality of pixels include a first pixel, a second pixel, and a third pixel, which are arranged in this order in a first direction, and the first four pixels include the first pixel and the second pixel, and the second four pixels include the second pixel and the third pixel, thereby enabling an increase in resolution.

[0082] [Variation 1] In the above embodiment, the light-receiving pixel PP includes four pixels P, but this is not limited to this, and instead, for example, the light-receiving pixel PP may include three or fewer pixels P, or may include five or more pixels P. Below, this variation will be described in detail using several examples.

[0083] 18 shows an example of the arrangement of multiple pixels P in a pixel array 21A according to this modified example. In this pixel array 21A, units U each containing 16 pixels P are repeatedly arranged. The 16 pixels P included in the unit U are arranged in four rows and four columns. These 16 pixels P include four pixels P1 and 12 pixels P2. In this example, as in the case of the above embodiment ( FIG. 5 ), four pixels P1 are arranged in two rows and two columns at the bottom right of the unit U.

[0084] 19A to 19D show an example of the operation of the pixel array 21 A. Each of Fig. 19A to 19D shows 36 pixels P arranged in 6 rows and 6 columns, with four pixels P1 in the center.

[0085] In the pixel array 21A, 16 pixels P are connected to form one light-receiving pixel PP, and the reflected light pulse L1 is detected by each light-receiving pixel PP. The 16 pixels P that make up this light-receiving pixel PP are arranged in four rows and four columns and can be switched. Specifically, in FIG. 19A, of the 36 pixels P, the 16 pixels P in the upper left corner make up the light-receiving pixel PP. In FIG. 19B, of the 36 pixels P, the 16 pixels P in the upper right corner make up the light-receiving pixel PP. In FIG. 19C, of ​​the 36 pixels P, the 16 pixels P in the lower right corner make up the light-receiving pixel PP. In the pixel array 21A, as shown in FIGS. 19A to 19D, the 16 pixels P that make up the light-receiving pixel PP can be switched in a time-division manner.

[0086] The connecting unit 29 in this pixel array 21A has 32 AND circuits and a 36-input OR circuit, as in the above embodiment ( FIG. 7 ). Of the 36 pixels P shown in FIG. 19 , four pixels P1 are connected to the 36-input OR circuit, as in the above embodiment ( FIG. 7 ). Furthermore, of these 36 pixels P, 32 pixels P2 are connected to the 36-input OR circuit via 32 AND circuits, as in the above embodiment ( FIG. 7 ).

[0087] 20 shows an example of the arrangement of multiple pixels P in another pixel array 21B according to this modified example. In this pixel array 21B, units U each including two pixels P are repeatedly arranged. The two pixels P included in the unit U are arranged side by side in the vertical direction. These two pixels P include one pixel P1 and one pixel P2. In this example, in the unit U, pixel P1 is arranged at the bottom and pixel P2 is arranged at the top.

[0088] 21A to 21D show an example of the operation of the pixel array 21B. Each of Fig. 21A to 21D shows three pixels P arranged in the vertical direction, with pixel P1 at the center.

[0089] In the pixel array 21B, two pixels P are connected to form one light-receiving pixel PP, and the reflected light pulse L1 is detected for each light-receiving pixel PP. The two pixels P that make up this light-receiving pixel PP can be switched. Specifically, in FIG. 21A, the upper two pixels P of the three pixels P make up the light-receiving pixel PP, and in FIG. 21B, the lower two pixels P of the three pixels P make up the light-receiving pixel PP. In the pixel array 21B, as shown in FIGS. 21A and 21B, the two pixels P that make up the light-receiving pixel PP can be switched in a time-division manner.

[0090] The connecting unit 29 in this pixel array 21B has two AND circuits and a three-input OR circuit, as in the above embodiment ( FIG. 7 ). One pixel P1 of the three pixels P shown in FIG. 21 is connected to the three-input OR circuit, as in the above embodiment ( FIG. 7 ). Furthermore, two pixels P2 of these three pixels P are connected to the three-input OR circuit via two AND circuits, as in the above embodiment ( FIG. 7 ).

[0091] 22 shows an example of the arrangement of multiple pixels P in another pixel array 21C according to this modification. In this pixel array 21C, units U each including five pixels P are repeatedly arranged. The five pixels P included in the unit U are arranged so that three pixels P aligned vertically and three pixels P aligned horizontally intersect each other, like a plus sign. The five pixels P include one pixel P1 and four pixels P2. In this example, in the unit U, pixel P1 is arranged in the center, and pixels P2 are arranged to the left, right, above, and below pixel P1.

[0092] 23A to 23E show an example of the operation of the pixel array 21C, each of which shows 13 pixels P including pixel P1 at the center.

[0093] In the pixel array 21C, five pixels P are connected to form one light-receiving pixel PP, and the reflected light pulse L1 is detected for each light-receiving pixel PP. The five pixels P that form this light-receiving pixel PP can be switched. Specifically, in FIG. 23A , of the 13 pixels P, five pixels P near the center form the light-receiving pixel PP; in FIG. 23B , of the 13 pixels P, five pixels P near the left form the light-receiving pixel PP; in FIG. 23C , of the 13 pixels P, five pixels P near the bottom form the light-receiving pixel PP; in FIG. 23D , of the 13 pixels P, five pixels P near the right form the light-receiving pixel PP; and in FIG. 23E , of the 13 pixels P, five pixels P near the top form the light-receiving pixel PP. In the pixel array 21C, as shown in FIGS. 23A to 23E, five pixels P that make up the light-receiving pixel PP can be switched in a time-division manner.

[0094] The connecting unit 29 in this pixel array 21C has four AND circuits and a 12-input OR circuit, as in the above embodiment ( FIG. 7 ). One pixel P1 of the 13 pixels P shown in FIG. 23 is connected to the 12-input OR circuit, as in the above embodiment ( FIG. 7 ). Twelve pixels P2 of these 13 pixels P are connected to the 12-input OR circuit via 12 AND circuits, as in the above embodiment ( FIG. 7 ).

[0095] [Variation 2] In the above embodiment, distance images PIC0, PIC1, PIC2, ​​and PIC3 are generated sequentially as shown in Figure 13, but this is not limiting, and instead, distance images PIC0 to PIC3 may be generated in parallel, for example. This variation will be described in detail below.

[0096] FIG. 24 shows an example of the operation of the distance measuring device 1 according to this modified example.

[0097] First, the control unit 14 sets a variable M to 0 (M=0) (step S201).

[0098] Next, the control unit 14 sets a variable N to 0 (N=0) (step S202).

[0099] Next, the connecting unit 29 connects four pixels P according to the variable N (step S203), similarly to step S102 in the above embodiment (FIG. 13).

[0100] Next, the distance measuring device 1 performs a distance measuring operation (step S204) in the same manner as step S103 in the above embodiment (FIG. 13).

[0101] Next, the control unit 14 checks whether the variable N is smaller than 4 (N<4) (step S205). If the variable N is smaller than 4 ("Y" in step S205), the control unit 14 increments the variable N (step S206). Then, the process returns to step S203. The distance measuring device 1 repeats the processes of steps S203 to S206 until the variable N becomes 4 or greater.

[0102] In step S205, if the variable N is 4 or more ("N" in step S205), the control unit 14 checks whether the variable M is smaller than a predetermined threshold value Mth (M<Mth) (step S207). If the variable M is smaller than the threshold value Mth ("Y" in step S207), the control unit 14 increments the variable M (step S208). Then, the process returns to step S202. The distance measuring device 1 repeats the processes of steps S202 to S208 until the variable M becomes equal to or greater than the threshold value Mth.

[0103] 25 shows an example of the operation of the distance measuring device 1 according to this modification. In FIG. 25, the numbers indicate the value of the variable N. In this example, the operation when the variable N is 0, the operation when the variable N is 1, the operation when the variable N is 2, and the operation when the variable N is 3 are repeated four times in this order. In other words, the threshold value Mth is 4.

[0104] 25, in the four periods in which the variable N is 0, the four upper left pixels P of the nine pixels P constitute the light-receiving pixel PP. Based on the timing code generated by the TDC unit 22, the histogram generation unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at this light-receiving pixel PP in the four periods in which the variable N is 0.

[0105] Similarly, in the four periods in which the variable N is 1, the four upper right pixels P of the nine pixels P constitute the light-receiving pixel PP. Based on the timing code generated by the TDC unit 22, the histogram generation unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at this light-receiving pixel PP in the four periods in which the variable N is 1.

[0106] Similarly, in the four periods in which the variable N is 2, the four pixels P at the bottom right of the nine pixels P constitute the light-receiving pixel PP. Based on the timing code generated by the TDC unit 22, the histogram generation unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at this light-receiving pixel PP in the four periods in which the variable N is 2.

[0107] Similarly, in the four periods in which the variable N is 3, the four pixels P at the bottom left of the nine pixels P constitute the light-receiving pixel PP. Based on the timing code generated by the TDC unit 22, the histogram generation unit 23 generates a histogram of the detection timing of the reflected light pulse L1 at this light-receiving pixel PP in the four periods in which the variable N is 3.

[0108] Next, distance image generator 24 generates four distance images (step S209). Specifically, distance image generator 24 generates distance image PIC0 based on the histogram for the period when variable N is 0, distance image PIC1 based on the histogram for the period when variable N is 1, distance image PIC2 based on the histogram for the period when variable N is 2, and distance image PIC3 based on the histogram for the period when variable N is 3.

[0109] The distance image generating unit 24 then performs image synthesis processing based on the four distance images PIC0 to PIC3 to generate the distance image PIC (step S210).

[0110] This is the end of this flow.

[0111] In this modified example, the distance measuring device 1 generates distance images PIC0 to PIC3 in parallel by repeating the operation when variable N is 0, the operation when variable N is 1, the operation when variable N is 2, and the operation when variable N is 3, in this order. This allows the distance measuring device 1 to make the effects of motion blur in the distance images PIC0 to PIC3 approximately the same when the subject is moving. The distance measuring device 1 generates the distance image PIC by performing image synthesis processing based on these four distance images PIC0 to PIC3. Therefore, the distance measuring device 1 can improve the accuracy of the distance image PIC when the subject is moving.

[0112] [Modification 3] In the above embodiment, as shown in Fig. 7, each of the nine pixels P generates a pulse signal PLS1, and the connecting unit 29 generates the pulse signal PLS based on the nine pulse signals PLS1, but this is not limitative. Below, this modification will be described in detail using several examples.

[0113] 26 shows an example of the configuration of a pixel array 21D according to this modification. The pixel array 21D has a plurality of pixels P and a connecting portion 29D. As in the above embodiment, the plurality of pixels P includes a pixel P1 and a pixel P2.

[0114] In this example, the pixel P has a photodiode PD. That is, while in the above-described embodiment ( FIGS. 3 and 7 ), the pixel P has the photodiode PD, the current source CS1, and the inverter IV1, in this modification, the pixel P has the photodiode PD.

[0115] The coupling section 29D has eight switches SW1 to SW8, a current source CS2, an inverter IV2, and a tri-state buffer BUF1.

[0116] The eight switches SW1 to SW8 are provided corresponding to the eight pixels P2 surrounding pixel P1, similar to the eight AND circuits AN1 to AN8 (FIG. 8) in the above embodiment. Each of these switches SW1 to SW8 is configured using, for example, a transfer gate. Switch SW1 corresponds to pixel P2, which is provided to the upper left of pixel P1. One end of switch SW1 receives a pulse signal PLS1 supplied from pixel P2 corresponding to switch SW1, the other end is connected to node N2, and a control terminal receives a control signal SEL1. When the control signal SEL1 is high, switch SW1 connects one end to the other end, and when the control signal SEL1 is low, it disconnects the one end from the other end. Switch SW2 corresponds to pixel P2, which is provided above pixel P1. The switch SW2 receives a pulse signal PLS1 from the pixel P2 corresponding to the switch SW2 at one end, has its other end connected to node N2, and a control terminal to which a control signal SEL2 is supplied. The switch SW3 corresponds to the pixel P2 located to the upper right of the pixel P1. The switch SW3 receives a pulse signal PLS1 from the pixel P2 corresponding to the switch SW3 at one end, has its other end connected to node N2, and a control terminal to which a control signal SEL3 is supplied. The switch SW4 corresponds to the pixel P2 located to the left of the pixel P1. The switch SW4 receives a pulse signal PLS1 from the pixel P2 corresponding to the switch SW4 at one end, has its other end connected to node N2, and a control terminal to which a control signal SEL4 is supplied. The switch SW5 corresponds to the pixel P2 located to the right of the pixel P1. The switch SW5 has one end that receives the pulse signal PLS1 supplied from the pixel P2 corresponding to the switch SW5, the other end that is connected to node N2, and a control terminal that receives the control signal SEL5. The switch SW6 corresponds to the pixel P2 located to the lower left of the pixel P1. The switch SW6 has one end that receives the pulse signal PLS1 supplied from the pixel P2 corresponding to the switch SW6, the other end that is connected to node N2, and a control terminal that receives the control signal SEL6. The switch SW7 corresponds to the pixel P2 located below the pixel P1.One end of switch SW7 receives the pulse signal PLS1 supplied from pixel P2 corresponding to switch SW7, the other end is connected to node N2, and a control terminal is supplied with control signal SEL7. Switch SW8 corresponds to pixel P2 located to the lower right of pixel P1. One end of switch SW8 receives the pulse signal PLS1 supplied from pixel P2 corresponding to switch SW8, and the other end is connected to node N2, and a control terminal is supplied with control signal SEL8.

[0117] The current source CS2 is configured to pass a predetermined current from the power supply node of the power supply voltage VDD toward the node N2.

[0118] Inverter IV2 is configured to generate pulse signal PLS by outputting a low level when the voltage at node N2 is higher than the logical threshold voltage Vth and outputting a high level when the voltage at node N2 is lower than the logical threshold voltage Vth.

[0119] In the connection unit 29D, three of the eight control signals SEL1 to SEL8 supplied to the eight switches SW1 to SW8 are set to a high level, and the remaining five are set to a low level. As a result, the photodiode PD of pixel P1 and the photodiodes PD of three of the eight pixels P2 are essentially connected to node N2. Inverter IV2 generates a pulse signal PLS based on the voltage at node N2. In this way, the connection unit 29D can connect four of the nine pixels P based on the eight control signals SEL1 to SEL8.

[0120] 27 shows an example of the configuration of another pixel array 21E according to this modification. The pixel array 21E has a plurality of pixels P and a connecting portion 29E. As in the above embodiment, the plurality of pixels P includes a pixel P1 and a pixel P2.

[0121] In this example, the pixel P has a photodiode PD, a current source CS1, an inverter IV1, and a TDC 90. That is, in the above-described embodiment ( FIGS. 3 and 7 ), the pixel P has a photodiode PD, a current source CS1, and an inverter IV1, but in this modification, the pixel P has a TDC 90 in addition to these three.

[0122] The TDC 90 is configured to generate, based on the pulse signal PLS1, a timing code corresponding to the detection timing of the reflected light pulse L1 at this pixel P. The TDC 90 supplies a bus signal corresponding to the generated timing code to a downstream circuit using a bus wiring that transmits multiple bits.

[0123] The connecting portion 29E has eight switch circuits SW11 to SW18 and an adder circuit ADD.

[0124] The eight switch circuits SW11 to SW18 are provided corresponding to the eight pixels P2 surrounding pixel P1, similar to the eight AND circuits AN1 to AN8 (FIG. 8) in the above embodiment. Switch circuit SW11 corresponds to pixel P2 located to the upper left of pixel P1. A signal corresponding to a timing code supplied from pixel P2 corresponding to switch circuit SW11 is input to the input terminal of switch circuit SW11, its output terminal is connected to adder circuit ADD, and its control terminal is supplied with control signal SEL1. When control signal SEL1 is high, switch circuit SW11 outputs a bus signal corresponding to the timing code supplied from pixel P2 corresponding to switch circuit SW11, and when control signal SEL1 is low, it outputs a bus signal with all bit values ​​low. Switch circuit SW12 corresponds to pixel P2 located above pixel P1. The input terminal of the switch circuit SW12 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to the switch circuit SW12, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with a control signal SEL2. The switch circuit SW13 corresponds to the pixel P2 located to the upper right of the pixel P1. The input terminal of the switch circuit SW13 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to the switch circuit SW13, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with a control signal SEL3. The switch circuit SW14 corresponds to the pixel P2 located to the left of the pixel P1. The input terminal of the switch circuit SW14 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to the switch circuit SW14, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with a control signal SEL4. The switch circuit SW15 corresponds to the pixel P2 located to the right of the pixel P1. The input terminal of the switch circuit SW15 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to this switch circuit SW15, the output terminal of which is connected to the adder circuit ADD, and the control terminal of which is supplied with the control signal SEL5. The switch circuit SW16 corresponds to the pixel P2 located to the lower left of the pixel P1.The input terminal of the switch circuit SW16 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to this switch circuit SW16, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with the control signal SEL6. The switch circuit SW17 corresponds to the pixel P2 located below the pixel P1. The input terminal of the switch circuit SW17 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to this switch circuit SW17, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with the control signal SEL7. The switch circuit SW18 corresponds to the pixel P2 located to the lower right of the pixel P1. The input terminal of the switch circuit SW18 receives a bus signal corresponding to the timing code supplied from the pixel P2 corresponding to this switch circuit SW18, its output terminal is connected to the adder circuit ADD, and its control terminal is supplied with the control signal SEL8.

[0125] The addition circuit ADD is configured to generate a timing code corresponding to the detection timing of the reflected light pulse L1 at the light-receiving pixel PP by performing an addition process based on the bus signal corresponding to the timing code supplied from the pixel P1 and the bus signals corresponding to the timing codes supplied from each of the switch circuits SW11 to SW18. Specifically, the addition circuit ADD performs an addition process to count the number of pixels P receiving the reflected light pulse L1 at each detection timing, thereby generating a timing code corresponding to the detection timing of the reflected light pulse L1 at the light-receiving pixel PP.

[0126] In the connecting unit 29E, three of the eight control signals SEL1 to SEL8 supplied to the eight switch circuits SW11 to SW18 are set to a high level, and the remaining five are set to a low level. As a result, the adder circuit ADD essentially receives a bus signal corresponding to the timing code supplied from pixel P1 and a bus signal corresponding to the timing code supplied from each of three of the eight pixels P2. The adder circuit ADD generates a timing code corresponding to the detection timing of the reflected light pulse L1 at the light-receiving pixel PP based on the bus signals corresponding to the timing codes supplied from these four pixels P. In this way, the connecting unit 29E can connect four of the nine pixels P based on the eight control signals SEL1 to SEL8.

[0127] [Variation 4] In the above embodiment, as shown in FIG. 6 , the four pixels P constituting the light-receiving pixel PP are sequentially switched over across the entire region of the pixel array 21. However, this is not limited to this. Instead, for example, the four pixels P constituting the light-receiving pixel PP may be sequentially switched over within a portion of the pixel array 21. Specifically, the distance measuring device 1 can sequentially switch over the four pixels P constituting the light-receiving pixel PP within a region related to a so-called ROI (Region of Interest). This allows the distance measuring device 1 to increase the resolution within the ROI region. As a result, for example, the amount of data in the distance image PIC can be reduced.

[0128] [Variation 5] In the above embodiment, the four pixels P that make up the light-receiving pixel PP are always switched sequentially, but this is not limited to this. Instead, the distance measuring device 1 may have, for example, an operation mode (operation mode M1) in which the four pixels P that make up the light-receiving pixel PP are fixed without being switched, and an operation mode (operation mode M2) in which the four pixels P that make up the light-receiving pixel PP are switched sequentially. This variation will be described in detail below.

[0129] 28 shows an example of the operation of a distance measuring system using distance measuring device 1 according to this modification. In this example, distance measuring device 1 generates a low-resolution distance image in the period before timing t101. The distance measuring system using distance measuring device 1 performs object detection based on this distance image. Then, when an object is detected within the measurement range based on this distance image, distance measuring device 1 generates a high-resolution distance image in the period from timing t101 to t102. Then, when an object is no longer detected within the measurement range based on this distance image, distance measuring device 1 generates a low-resolution distance image in the period after timing t102. Then, the distance measuring system using distance measuring device 1 performs object detection based on this distance image.

[0130] In the period before timing t101 and the period after timing t102, the ranging device 1 operates in operation mode M1. In this operation mode M1, the ranging device 1 fixes the four pixels P that make up the light-receiving pixel PP without switching them. In this example, of the nine pixels P arranged in three rows and three columns, including pixel P1 at the center, the four upper left pixels P make up the light-receiving pixel PP. Therefore, the resolution of the distance image is low. On the other hand, because the ranging device 1 does not switch the four pixels P that make up the light-receiving pixel PP, the measurement period T is shortened. Therefore, in a ranging system using this ranging device 1, object detection can be performed more frequently, and object detection can be performed quickly when an object enters the measurement range.

[0131] During the period from timing t101 to t102, the distance measuring device 1 operates in operation mode M2. In this operation mode M2, the distance measuring device 1 generates distance images PIC0 to PIC3 by sequentially switching between the four pixels P that make up the light-receiving pixel PP, as in the above embodiment (FIG. 6), and generates distance image PIC by performing image synthesis processing based on these distance images PIC0 to PIC3. This lengthens the measurement period T. On the other hand, the distance measuring device 1 can increase the resolution of the distance images.

[0132] [Other Modifications] Two or more of these modifications may be combined.

[0133] 2. Application Examples to Mobile Bodies The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0134] FIG. 29 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0135] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 29, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0136] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0137] The body system control unit 12020 controls the operation of various devices equipped in 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 device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0138] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0139] The imaging unit 12031 is an optical 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.

[0140] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0141] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle 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 the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0142] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0143] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0144] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 29, the output devices are exemplified by 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 on-board display and a head-up display.

[0145] FIG. 30 is a diagram showing an example of the installation position of the imaging unit 12031.

[0146] In FIG. 30 , a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as an imaging unit 12031.

[0147] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0148] 30 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0149] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0150] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0151] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes 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 a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0152] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0153] The above describes an example of a vehicle control system to which the technology disclosed herein can be applied. The technology disclosed herein can be applied to the imaging unit 12031 of the above-described configuration. This allows the vehicle control system 12000 to increase the resolution of distance images. As a result, the vehicle control system 12000 can achieve highly accurate functions such as a vehicle collision avoidance or collision mitigation function, a following driving function based on the following distance, a vehicle speed maintenance function, a vehicle collision warning function, and a vehicle lane departure warning function.

[0154] The present technology has been described above by giving the embodiments, some modified examples, and specific application examples thereof, but the present technology is not limited to these embodiments and can be modified in various ways.

[0155] For example, in each of the above embodiments, the pixel P is provided as shown in FIG. 3, but the circuit configuration of the pixel P is not limited to this, and various circuit configurations can be applied.

[0156] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0157] The present technology can be configured as follows: According to the present technology configured as follows, it is possible to improve detection accuracy.

[0158] (1) A photodetection device comprising: a pixel array having a plurality of pixels, each including a light-receiving element capable of detecting a light pulse, wherein two or more of the plurality of pixels can be connected as light-receiving pixels, and wherein a detection signal can be generated according to the detection timing of the light pulse by performing a light-receiving operation on a unit basis of the light-receiving pixels; a light-receiving control circuit capable of controlling the operation of the pixel array to switch some of the two or more pixels that constitute the light-receiving pixels; and a distance image generation circuit capable of generating a first distance image based on a plurality of detection signals generated by the plurality of light-receiving pixels when the two or more pixels are first two or more pixels, and capable of generating a second distance image based on the plurality of detection signals when the two or more pixels are second two or more pixels, and capable of generating a composite distance image by performing image synthesis processing based on the first distance image and the second distance image. (2) The photodetector device according to (1), wherein the plurality of pixels include a first pixel, a second pixel, and a third pixel, the first pixel, the second pixel, and the third pixel are arranged in this order in a first direction, the first two or more pixels include the first pixel and the second pixel, and the second two or more pixels include the second pixel and the third pixel.(3) The plurality of pixels include a first pixel, a second pixel, a third pixel, a fourth pixel, a fifth pixel, a sixth pixel, a seventh pixel, an eighth pixel, and a ninth pixel, the first pixel, the second pixel, and the third pixel being arranged in this order in a first direction, the fourth pixel, the fifth pixel, and the sixth pixel being arranged in this order in the first direction, the seventh pixel, the eighth pixel, and the ninth pixel being arranged in this order in the first direction, the fourth pixel, the first pixel, and the seventh pixel being arranged in this order in a second direction, the fifth pixel, the second pixel, and the eighth pixel being arranged in this order in the second direction, and the sixth pixel, the third pixel, and the ninth pixel being arranged in this order in the second direction, The photodetection device according to (1), wherein the first pixel, the second pixel, the fourth pixel, and the fifth pixel are capable of constituting the light receiving pixel; the second pixel, the third pixel, the fifth pixel, and the sixth pixel are capable of constituting the light receiving pixel; the second pixel, the third pixel, the eighth pixel, and the ninth pixel are capable of constituting the light receiving pixel; and the first pixel, the second pixel, the seventh pixel, and the eighth pixel are capable of constituting the light receiving pixel.(4) The optical detection device described in (1), wherein the first two or more pixels include the first pixel, the second pixel, the fourth pixel, and the fifth pixel; the second two or more pixels include the second pixel, the third pixel, the fifth pixel, and the sixth pixel; the third two or more pixels include the second pixel, the third pixel, the eighth pixel, and the ninth pixel; and the fourth two or more pixels include the first pixel, the second pixel, the seventh pixel, and the eighth pixel; and the distance image generation circuit is further capable of generating a third distance image based on the plurality of detection signals when the two or more pixels are the third two or more pixels, and is capable of generating a fourth distance image based on the plurality of detection signals when the two or more pixels are the fourth two or more pixels, and is capable of generating the composite distance image based on the first distance image, the second distance image, the third distance image, and the fourth distance image. (5) The photodetector according to any one of (1) to (4), wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal corresponding to the optical pulse, and wherein the pixel array has a connection circuit capable of selecting the two or more pixels constituting the light receiving pixel based on an instruction from the light receiving control circuit and generating the detection signal based on the pulse signal generated by each of the selected two or more pixels. (6) The photodetector according to any one of (1) to (4), wherein the pixel array has a connection circuit capable of selecting the two or more pixels constituting the light receiving pixel based on an instruction from the light receiving control circuit and connecting the light receiving elements of the selected two or more pixels to each other, thereby generating the detection signal, which is a pulse signal corresponding to the optical pulse detected in each of the selected two or more pixels.(7) The photodetector device according to any one of (1) to (4), wherein each of the plurality of pixels further includes a data generating circuit capable of generating timing data indicating a detection timing of the light pulse, and the pixel array includes a connecting circuit capable of selecting the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit, and generating the detection signal based on the timing data generated by each of the two or more selected pixels. (8) A photodetection device described in any of (1) to (7), wherein during a first period, the pixel array is capable of selecting the first two or more pixels as the two or more pixels that constitute the light-receiving pixel based on instructions from the light-receiving control circuit, and the distance image generation circuit is capable of generating a first distance image based on the multiple detection signals generated by the multiple light-receiving pixels; during a second period, the pixel array is capable of selecting the second two or more pixels as the two or more pixels that constitute the light-receiving pixel based on instructions from the light-receiving control circuit, and the distance image generation circuit is capable of generating a second distance image based on the multiple detection signals generated by the multiple light-receiving pixels; and the distance image generation circuit is capable of generating the composite distance image based on the first distance image and the second distance image.(9) In a first period, the pixel array can select the first two or more pixels as the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate first data based on the plurality of detection signals generated by the plurality of light-receiving pixels; in a second period, the pixel array can select the second two or more pixels as the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate second data based on the plurality of detection signals generated by the plurality of light-receiving pixels; in a third period, the pixel array can select the first two or more pixels as the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate third data based on the plurality of detection signals generated by the plurality of light-receiving pixels; The photodetector device of any of (1) to (7), wherein during a second period, the pixel array is capable of selecting the second two or more pixels as the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit, the distance image generation circuit is capable of generating fourth data based on the multiple detection signals generated by the multiple light-receiving pixels, the distance image generation circuit is capable of generating the first distance image based on the first data and the third data, the second distance image based on the second data and the fourth data, and the composite distance image is capable of generating the first distance image and the second distance image. (10) The photodetector device of any of (1) to (9), wherein the pixel array further includes a connection circuit capable of selecting the two or more pixels constituting the light-receiving pixel based on an instruction from the light-receiving control circuit and generating the detection signal corresponding to the detection timing of the light pulse at each of the selected two or more pixels, the light-receiving elements are provided on a first semiconductor substrate, and the connection circuit is provided on a second semiconductor substrate overlaid on the first semiconductor substrate.(11) The photodetector according to (10), wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal in response to the light pulse, the pulse generating circuit being provided on the first semiconductor substrate. (12) The photodetector according to (10), wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal in response to the light pulse, the pulse generating circuit being provided on a third semiconductor substrate overlaid on the first semiconductor substrate and the second semiconductor substrate. (13) The photodetector according to any of (1) to (12), wherein the light-receiving region of the light-receiving pixel is a rectangular region. (14) The photodetector according to any of (1) to (13), wherein the pixel array further includes signal lines capable of transmitting the plurality of detection signals generated by the plurality of light-receiving pixels to the distance image generation circuit. (15) A distance measuring device comprising: a light source capable of emitting a first light pulse; a pixel array having a plurality of pixels, each including a light receiving element capable of detecting a second light pulse corresponding to the first light pulse, wherein two or more of the plurality of pixels can be connected as light receiving pixels and capable of generating a detection signal corresponding to the detection timing of the second light pulse by performing light receiving operations on a unit basis of the light receiving pixels; a light receiving control circuit capable of controlling the operation of the pixel array to switch some of the two or more pixels that constitute the light receiving pixels; and a distance image generation circuit capable of generating a first distance image based on a plurality of detection signals generated by the plurality of light receiving pixels when the two or more pixels are first two or more pixels, and capable of generating a second distance image based on the plurality of detection signals when the two or more pixels are second two or more pixels, and capable of generating a composite distance image by performing image synthesis processing based on the first distance image and the second distance image.

[0159] This application claims priority based on Japanese Patent Application No. 2024-83402, filed on May 22, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0160] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A photodetection device comprising: a pixel array having a plurality of pixels, each including a light-receiving element capable of detecting light pulses, wherein two or more of the plurality of pixels can be connected as light-receiving pixels, and wherein a detection signal corresponding to the detection timing of the light pulse can be generated by performing light-receiving operations on a unit basis of the light-receiving pixels; a light-receiving control circuit capable of controlling the operation of the pixel array to switch some of the two or more pixels that constitute the light-receiving pixels; and a distance image generation circuit capable of generating a first distance image based on a plurality of detection signals generated by the plurality of light-receiving pixels when the two or more pixels are first two or more pixels, and capable of generating a second distance image based on the plurality of detection signals when the two or more pixels are second two or more pixels, and capable of generating a composite distance image by performing image synthesis processing based on the first distance image and the second distance image.

2. The photodetector device according to claim 1, wherein the plurality of pixels include a first pixel, a second pixel, and a third pixel, the first pixel, the second pixel, and the third pixel being arranged in this order in a first direction, the first two or more pixels including the first pixel and the second pixel, and the second two or more pixels including the second pixel and the third pixel.

3. The plurality of pixels include a first pixel, a second pixel, a third pixel, a fourth pixel, a fifth pixel, a sixth pixel, a seventh pixel, an eighth pixel, and a ninth pixel, wherein the first pixel, the second pixel, and the third pixel are arranged in this order in a first direction, the fourth pixel, the fifth pixel, and the sixth pixel are arranged in this order in the first direction, the seventh pixel, the eighth pixel, and the ninth pixel are arranged in this order in the first direction, the fourth pixel, the first pixel, and the seventh pixel are arranged in this order in a second direction, the fifth pixel, the second pixel, and the eighth pixel are arranged in this order in the second direction, and the sixth pixel, the third pixel, and the ninth pixel are arranged in this order in the second direction, 2. The photodetection device according to claim 1, wherein the first pixel, the second pixel, the fourth pixel, and the fifth pixel can constitute the light receiving pixel; the second pixel, the third pixel, the fifth pixel, and the sixth pixel can constitute the light receiving pixel; the second pixel, the third pixel, the eighth pixel, and the ninth pixel can constitute the light receiving pixel; and the first pixel, the second pixel, the seventh pixel, and the eighth pixel can constitute the light receiving pixel.

4. The optical detection device of claim 3, wherein the first two or more pixels include the first pixel, the second pixel, the fourth pixel, and the fifth pixel; the second two or more pixels include the second pixel, the third pixel, the fifth pixel, and the sixth pixel; the third two or more pixels include the second pixel, the third pixel, the eighth pixel, and the ninth pixel; and the fourth two or more pixels include the first pixel, the second pixel, the seventh pixel, and the eighth pixel; and the distance image generation circuit is further capable of generating a third distance image based on the plurality of detection signals when the two or more pixels are the third two or more pixels, and is capable of generating a fourth distance image based on the plurality of detection signals when the two or more pixels are the fourth two or more pixels, and is capable of generating the composite distance image based on the first distance image, the second distance image, the third distance image, and the fourth distance image.

5. The photodetector device according to claim 1, wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal corresponding to the light pulse, and the pixel array has a connecting circuit capable of selecting the two or more pixels constituting the light-receiving pixel based on instructions from the light-receiving control circuit, and generating the detection signal based on the pulse signal generated by each of the two or more selected pixels.

6. The photodetection device according to claim 1, wherein the pixel array has a connection circuit that is capable of generating the detection signal, which is a pulse signal corresponding to the optical pulse detected in each of the selected two or more pixels, by selecting the two or more pixels that constitute the photodetector pixel based on instructions from the photodetection control circuit and connecting the photodetectors of the selected two or more pixels to each other.

7. The photodetector device according to claim 1, wherein each of the plurality of pixels further includes a data generation circuit capable of generating timing data indicating the detection timing of the light pulse, and the pixel array has a connection circuit capable of selecting the two or more pixels constituting the light-receiving pixel based on instructions from the light-receiving control circuit, and generating the detection signal based on the timing data generated by each of the two or more selected pixels.

8. The optical detection device described in claim 1, wherein during a first period, the pixel array is capable of selecting the first two or more pixels as the two or more pixels that constitute the light-receiving pixel based on instructions from the light-receiving control circuit, and the distance image generation circuit is capable of generating a first distance image based on the multiple detection signals generated by the multiple light-receiving pixels; during a second period, the pixel array is capable of selecting the second two or more pixels as the two or more pixels that constitute the light-receiving pixel based on instructions from the light-receiving control circuit, and the distance image generation circuit is capable of generating a second distance image based on the multiple detection signals generated by the multiple light-receiving pixels; and the distance image generation circuit is capable of generating the composite distance image based on the first distance image and the second distance image.

9. In a first period, the pixel array can select the first two or more pixels as the two or more pixels that constitute the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate first data based on the plurality of detection signals generated by the plurality of light-receiving pixels; in a second period, the pixel array can select the second two or more pixels as the two or more pixels that constitute the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate second data based on the plurality of detection signals generated by the plurality of light-receiving pixels; in a third period, the pixel array can select the first two or more pixels as the two or more pixels that constitute the light-receiving pixel based on an instruction from the light-receiving control circuit, and the distance image generation circuit can generate third data based on the plurality of detection signals generated by the plurality of light-receiving pixels; The photodetection device of claim 1, wherein during a second period, the pixel array is capable of selecting the second two or more pixels as the two or more pixels that constitute the light-receiving pixel based on instructions from the light-receiving control circuit, the distance image generation circuit is capable of generating fourth data based on the multiple detection signals generated by the multiple light-receiving pixels, the distance image generation circuit is capable of generating the first distance image based on the first data and the third data, the second distance image based on the second data and the fourth data, and the composite distance image based on the first distance image and the second distance image.

10. The photodetector device according to claim 1, wherein the pixel array further includes a connection circuit that selects the two or more pixels that constitute the photodetector pixel based on instructions from the photodetection control circuit and is capable of generating the detection signal according to the detection timing of the light pulse in each of the two or more selected pixels, and wherein the photodetector is provided on a first semiconductor substrate, and the connection circuit is provided on a second semiconductor substrate superimposed on the first semiconductor substrate.

11. The photodetector according to claim 10, wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal corresponding to the optical pulse, the pulse generating circuit being provided on the first semiconductor substrate.

12. The photodetector according to claim 10, wherein each of the plurality of pixels further includes a pulse generating circuit capable of generating a pulse signal corresponding to the optical pulse, and the pulse generating circuit is provided on a third semiconductor substrate superimposed on the first semiconductor substrate and the second semiconductor substrate.

13. The photodetector according to claim 1, wherein the light-receiving area of ​​the light-receiving pixel is a rectangular area.

14. The photodetection device according to claim 1, wherein the pixel array further comprises signal lines capable of transmitting the detection signals generated by the light-receiving pixels to the distance image generation circuit.

15. A distance measuring device comprising: a light source capable of emitting a first light pulse; a pixel array having a plurality of pixels, each including a light receiving element capable of detecting a second light pulse corresponding to the first light pulse, wherein two or more of the plurality of pixels can be connected as light receiving pixels and capable of generating a detection signal corresponding to the detection timing of the second light pulse by performing light receiving operations on a light receiving pixel basis; a light receiving control circuit capable of controlling the operation of the pixel array to switch some of the two or more pixels constituting the light receiving pixels; and a distance image generation circuit capable of generating a first distance image based on a plurality of detection signals generated by the plurality of light receiving pixels when the two or more pixels are first two or more pixels, and capable of generating a second distance image based on the plurality of detection signals when the two or more pixels are second two or more pixels, and capable of generating a composite distance image by performing image synthesis processing on the first distance image and the second distance image.

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