Light source device, distance measuring device, and distance measuring method

Abstract

This light source device comprises a light emission unit, a sweeping unit, and a control unit. The light emission unit has a plurality of light emission elements that are arranged along a first direction. The sweeping unit sweeps light emitted from the plurality of light emission elements along a second direction orthogonal to the first direction. The control unit carries out control that makes the number of times light is emitted by a first light emission element group included in the plurality of light emission elements greater than the number of times light is emitted by a second light emission element group not included in the first light emission element group.

Description

Technical Field

[0001] The present disclosure relates to a light source device, a distance measuring device, and a distance measuring method.

Background Art

[0002] Conventionally, there has been a distance measuring device that measures the distance to an object as a reflector by emitting laser light to the outside and receiving the reflected light, such as LiDAR (Light Detection and Ranging). In this type of distance measuring device, in order to improve the accuracy of distance measurement, the number of measurements in a more important area may be increased (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art, there has been a problem that the accuracy in the scanning direction can be improved, but the accuracy in the direction orthogonal to the scanning direction cannot be increased.

[0005] Therefore, the present disclosure proposes a light source device, a distance measuring device, and a distance measuring method capable of performing high-precision distance measurement in a direction orthogonal to the scanning direction.

Means for Solving the Problems

[0006] To solve the above problems, one embodiment of a light source device according to the present disclosure includes: a light-emitting unit in which a plurality of light-emitting elements are arranged along a first direction; a scanning unit that scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction; and a control unit that controls the number of times a first group of light-emitting elements included in the plurality of light-emitting elements emits light to be greater than the number of times a second group of light-emitting elements not included in the first group of light-emitting elements emits light. [Brief explanation of the drawing]

[0007] [Figure 1] This is a block diagram showing a schematic configuration example of a ToF sensor as a distance measuring device according to this embodiment. [Figure 2] This is a diagram illustrating the optical system of the ToF sensor according to this embodiment. [Figure 3] This block diagram shows a schematic configuration example of the light-receiving unit according to this embodiment. [Figure 4] This is a schematic diagram showing an example of the general configuration of the LD array and SPAD array according to this embodiment. [Figure 5] This is a circuit diagram showing a schematic configuration example of a SPAD pixel according to this embodiment. [Figure 6] This is a block diagram showing a more detailed configuration example of the SPAD adder according to this embodiment. [Figure 7] This figure shows the histogram generated by the calculation unit. [Figure 8] This diagram illustrates the regions detected by the LD array and SPAD array. [Figure 9] This figure shows the relationship between the measurement distance and the light emission intensity. [Figure 10] This figure shows the relationship between measurement distance, light emission intensity, and the number of measurements. [Figure 11] This diagram shows the installation location of the ToF sensor in the modified example 1. [Figure 12] This figure shows the installation position of the ToF sensor according to modified example 2. [Figure 13] This flowchart shows the overall processing steps performed by the ToF sensor. [Figure 14]It is a block diagram showing an example of the schematic configuration of a vehicle control system. [Figure 15] It is an explanatory diagram showing an example of the installation positions of an external information detection unit and an imaging unit.

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. In each of the following embodiments, the same parts are denoted by the same reference numerals, and overlapping descriptions are omitted.

[0009] Also, in this specification and the drawings, there are cases where a plurality of components having substantially the same functional configuration are distinguished by attaching different numbers after the same reference numeral. However, when it is not necessary to particularly distinguish each of the plurality of components having substantially the same functional configuration, only the same reference numeral is attached.

[0010] Note that the description will be made in the following order. 1. Embodiment 1.1 Distance measurement device (ToF sensor) 1.2 Optical system 1.3 Light receiving unit 1.4 LD array and SPAD array 1.5 SPAD pixel 1.6 Schematic operation example of SPAD pixel 1.7 SPAD addition unit 1.8 Sampling period 1.9 Histogram 1.10 Region to be detected 1.11 Number of detections 2. Application example 3. Summary

[0011] 1. Embodiment First, the embodiment will be described in detail below with reference to the drawings.

[0012] 1.1 Distance measurement device (ToF sensor) Figure 1 is a block diagram showing a schematic configuration example of a ToF sensor as a distance measuring device according to this embodiment. As shown in Figure 1, the ToF sensor 1 comprises a control unit 11, a light-emitting unit 13, a light-receiving unit 14, a calculation unit 15, and an external interface (I / F) 19. The control unit 11 and the light-emitting unit 13 are included in the light source device 2.

[0013] The control unit 11 is composed of an information processing device such as a CPU (Central Processing Unit), and controls each part of the ToF sensor 1.

[0014] The external I / F19 may be a communication adapter for establishing communication with an external host 80 via a communication network compliant with any standard, such as a wireless LAN (Local Area Network), wired LAN, CAN (Controller Area Network), LIN (Local Interconnect Network), or FlexRay (registered trademark).

[0015] Here, the host 80 may be, for example, an ECU (Engine Control Unit) mounted on a mobile vehicle such as an automobile if the ToF sensor 1 is mounted on such a vehicle. Also, if the ToF sensor 1 is mounted on an autonomous mobile robot such as a household pet robot, a robotic vacuum cleaner, an unmanned aerial vehicle, or a follow-me transport robot, the host 80 may be a control device that controls the autonomous mobile robot.

[0016] The light-emitting unit 13, although its details will be described later, is equipped with semiconductor laser diodes as a light source, which are multiple light-emitting elements arranged in a one-dimensional array along the vertical direction (first direction), and emits pulsed laser light L1 with a predetermined time width at a predetermined period (also called the emission period). The light-emitting unit 13 also emits laser light L1 with a time width of 1 ns (nanosecond) at a period of 1 MHz (megahertz). The laser light L1 emitted from the light-emitting unit 13 is reflected by an object 90 if such an object exists within the distance measurement range, and the reflected light L2 is incident on the light-receiving unit 14.

[0017] The light-receiving unit 14, although its details will be described later, is, for example, arranged in a two-dimensional grid and comprises multiple SPAD pixels, which are light-receiving elements that each receive light from multiple semiconductor laser diodes. It outputs information (for example, corresponding to the number of detection signals described later) regarding the number of SPAD pixels that detected the incidence of photons after the emission of light from the light-emitting unit 13 (hereinafter referred to as the number of detections). For example, the light-receiving unit 14 detects the incidence of photons at a predetermined sampling period for each emission of light from the light-emitting unit 13 and outputs the number of detections.

[0018] The calculation unit 15 aggregates the number of detections output from the light receiving unit 14 for each of several SPAD pixels (for example, corresponding to one or more macro pixels described later), and creates a histogram based on the pixel values ​​obtained from this aggregation, with the horizontal axis representing flight time and the vertical axis representing cumulative pixel values. For example, the calculation unit 15 aggregates the number of detections at a predetermined sampling frequency for each emission of light from the light-emitting unit 13 and obtains the pixel value, and repeats this process for multiple emissiones of light from the light-emitting unit 13, thereby creating a histogram with the horizontal axis (histogram bins) representing the sampling period corresponding to flight time and the vertical axis representing the cumulative pixel values ​​obtained by accumulating the pixel values ​​obtained at each sampling period.

[0019] Furthermore, the calculation unit 15 applies a predetermined filter to the created histogram and then identifies the flight time at which the cumulative pixel value peaks from the filtered histogram. Based on the identified flight time, the calculation unit 15 calculates the distance from the ToF sensor 1 or the device on which it is mounted to the object 90 that is within the ranging range. The distance information calculated by the calculation unit 15 may be output to the host 80, for example, via an external I / F 19.

[0020] 1.2 Optical Systems Figure 2 is a diagram illustrating the optical system of the ToF sensor according to this embodiment. Figure 2 is a so-called scanning type optical system that scans the field of view of the light receiving unit 14 in the horizontal direction.

[0021] As shown in Figure 2, the ToF sensor 1 comprises an LD array 131, a collimator lens 132, a half mirror 133, a galvanometer mirror 135, a light-receiving lens 146, and a SPAD array 141 as an optical system. The LD array 131, collimator lens 132, half mirror 133, and galvanometer mirror 135 are included, for example, in the light-emitting unit 13 in Figure 1. The light-receiving lens 146 and SPAD array 141 are included, for example, in the light-receiving unit 14 in Figure 1.

[0022] In the configuration shown in Figure 2, the laser light L1 emitted from the LD array 131 is converted into a rectangular parallel light with a vertically elongated intensity spectrum in its cross-section by the collimator lens 132, and then incident on the half mirror 133. The half mirror 133 reflects a portion of the incident laser light L1. The laser light L1 reflected by the half mirror 133 is incident on the galvanometer mirror 135. The galvanometer mirror 135 is vibrated horizontally around a predetermined rotation axis by a drive unit 134 that operates based on control from the control unit 11, for example. As a result, the laser light L1 is horizontally scanned so that the field of view SR of the laser light L1 reflected by the galvanometer mirror 135 reciprocates across the distance measurement range AR in the horizontal direction (second direction). In other words, the drive unit 134 and the galvanometer mirror 135 function as scanning units that scan the light emitted by the LD array 131 along the horizontal direction. Furthermore, the drive unit 134 can utilize MEMS (Micro Electro Mechanical System), micromotors, or the like.

[0023] The laser beam L1 reflected by the galvanometer mirror 135 is reflected by an object 90 located within the distance measurement range AR and enters the galvanometer mirror 135 as reflected light L2. A portion of the reflected light L2 that enters the galvanometer mirror 135 passes through the half-mirror 133 and enters the light-receiving lens 146, thereby forming an image on a specific SPAD array 142 in the SPAD array 141. The SPAD array 142 may be the entire SPAD array 141 or a part of it.

[0024] 1.3 Photodetector Figure 3 is a block diagram showing a schematic configuration example of the light receiving unit according to this embodiment. As shown in Figure 3, the light receiving unit 14 includes a SPAD array 141, a timing control circuit 143, a drive circuit 144, and an output circuit 145.

[0025] The SPAD array 141 comprises multiple SPAD pixels 20 arranged in a two-dimensional grid. Each column of the multiple SPAD pixels 20 is connected to a pixel drive line LD (vertical direction in the diagram), and each row is connected to an output signal line LS (horizontal direction in the diagram). One end of the pixel drive line LD is connected to the output terminal of the drive circuit 144 corresponding to each column, and one end of the output signal line LS is connected to the input terminal of the output circuit 145 corresponding to each row.

[0026] In this embodiment, the reflected light L2 is detected using all or part of the SPAD array 141. The area used in the SPAD array 141 (SPAD array 142) may be a vertically elongated rectangle, which is the same as the image of the reflected light L2 that is imaged on the SPAD array 141 when the entire laser beam L1 is reflected as reflected light L2. However, it is not limited to this, and may be modified in various ways, such as being a larger or smaller area than the image of the reflected light L2 that is imaged on the SPAD array 141.

[0027] The drive circuit 144 includes a shift register and an address decoder, and drives each SPAD pixel 20 of the SPAD array 141, either all pixels simultaneously or in column units. The drive circuit 144 includes at least a circuit that applies a quench voltage V_QCH (described later) to each SPAD pixel 20 in a selected column within the SPAD array 141, and a circuit that applies a selection control voltage V_SEL (described later) to each SPAD pixel 20 in the selected column. The drive circuit 144 then selects the SPAD pixels 20 to be used for detecting photon incidence in column units by applying the selection control voltage V_SEL to the pixel drive line LD corresponding to the column to be read.

[0028] The signals (called detection signals) V_OUT output from each SPAD pixel 20 in a column selected and scanned by the drive circuit 144 are input to the output circuit 145 through each of the output signal lines LS. The output circuit 145 outputs the detection signals V_OUT input from each SPAD pixel 20 to the SPAD adder 40 provided for each macro pixel, which will be described later.

[0029] The timing control circuit 143 includes a timing generator that generates various timing signals, and controls the drive circuit 144 and the output circuit 145 based on the various timing signals generated by the timing generator.

[0030] 1.4 LD Arrays and SPAD Arrays Figure 4 is a schematic diagram showing an example of the general configuration of the LD array and SPAD array according to this embodiment. As shown in Figure 4, the LD array 131 has a configuration in which, for example, a plurality of semiconductor laser diodes, LD131-1 to 131-8, are arranged in a one-dimensional array along the vertical direction. In this embodiment, an example in which the LD array 131 has eight LDs is described, but the number of LDs can be any number.

[0031] The SPAD array 142 has a configuration in which, for example, a plurality of SPAD pixels 20 are arranged in a two-dimensional grid. The plurality of SPAD pixels 20 are grouped into a plurality of macro pixels 30, each consisting of a predetermined number of SPAD pixels 20 arranged in the row and / or column directions. The shape of the region formed by connecting the outer edges of the SPAD pixels 20 located on the outermost periphery of each macro pixel 30 is a predetermined shape (for example, a rectangle).

[0032] The SPAD array 142 is composed of multiple macro pixels 30 arranged vertically (corresponding to the column direction). In this embodiment, the SPAD array 142 is divided into multiple regions (hereinafter referred to as SPAD regions) vertically. In the example shown in Figure 4, the SPAD array 142 is divided into eight SPAD regions 142-1 to 142-8, each receiving laser light emitted by LDs 131-1 to 131-8. The uppermost SPAD region 142-1 corresponds to, for example, the uppermost 1 / 8 region in the field of view SR of the SPAD array 142, and receives laser light emitted by LD 131-1. Similarly, the SPAD region 142-2 below it corresponds to, for example, the second 1 / 8 region from the top in the field of view SR, and receives laser light emitted by LD 131-2. Similarly, SPAD regions 142-3 to 142-8 each correspond to 1 / 8 of the field of view SR, and receive the laser light emitted by LD131-3 to 131-8.

[0033] 1.5 SPAD pixels Figure 5 is a circuit diagram showing a schematic configuration example of a SPAD pixel according to this embodiment. As shown in Figure 5, the SPAD pixel 20 includes a photodiode 21 as a light-receiving element and a readout circuit 22 that detects when a photon is incident on the photodiode 21. When a photon is incident on the photodiode 21 while a reverse bias voltage V_SPAD, which is greater than the breakdown voltage, is applied between its anode and cathode, the photodiode 21 generates an avalanche current.

[0034] The readout circuit 22 includes a quench resistor 23, a digital converter 25, an inverter 26, a buffer 27, and a selection transistor 24. The quench resistor 23 is composed of, for example, an N-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor; hereinafter referred to as an NMOS transistor), with its drain connected to the anode of the photodiode 21 and its source grounded via the selection transistor 24. In addition, a quench voltage V_QCH, which is set in advance to cause the NMOS transistor to act as a quench resistor, is applied to the gate of the NMOS transistor constituting the quench resistor 23 from the drive circuit 144 via the pixel drive line LD.

[0035] In this embodiment, the photodiode 21 is a SPAD. The SPAD is an avalanche photodiode that operates in Geiger mode when a reverse bias voltage greater than the breakdown voltage is applied between its anode and cathode, and is capable of detecting the incidence of a single photon.

[0036] The digital converter 25 comprises a resistor 251 and an NMOS transistor 252. The drain of the NMOS transistor 252 is connected to the power supply voltage VDD via the resistor 251, and its source is grounded. The voltage at the connection point N1 between the anode of the photodiode 21 and the quench resistor 23 is applied to the gate of the NMOS transistor 252.

[0037] The inverter 26 comprises a P-type MOSFET (hereinafter referred to as a PMOS transistor) 261 and an NMOS transistor 262. The drain of the PMOS transistor 261 is connected to the power supply voltage VDD, and its source is connected to the drain of the NMOS transistor 262. The drain of the NMOS transistor 262 is connected to the source of the PMOS transistor 261, and its source is grounded. The gates of the PMOS transistor 261 and the NMOS transistor 262 are each supplied with a voltage at the connection point N2 between resistor 251 and the drain of NMOS transistor 252. The output of the inverter 26 is input to buffer 27.

[0038] Buffer 27 is a circuit for impedance conversion. When an output signal is input from inverter 26, it converts the input output signal's impedance and outputs it as a detection signal V_OUT.

[0039] The selection transistor 24 is, for example, an NMOS transistor, whose drain is connected to the source of an NMOS transistor that constitutes the quench resistor 23, and whose source is grounded. The selection transistor 24 is connected to the drive circuit 144, and when a selection control voltage V_SEL from the drive circuit 144 is applied to the gate of the selection transistor 24 via the pixel drive line LD, it changes from the off state to the on state.

[0040] 1.6 Schematic Example of SPAD Pixel Operation The readout circuit 22 illustrated in Figure 5 operates, for example, as follows: First, a selection control voltage V_SEL is applied from the drive circuit 144 to the selection transistor 24, and while the selection transistor 24 is in the ON state, a reverse bias voltage V_SPAD, which is greater than the breakdown voltage, is applied to the photodiode 21. This allows the photodiode 21 to operate.

[0041] On the other hand, since the selection control voltage V_SEL is not applied to the selection transistor 24 from the drive circuit 144, and the selection transistor 24 is in the off state, the reverse bias voltage V_SPAD is not applied to the photodiode 21, thus prohibiting the operation of the photodiode 21.

[0042] When a photon is incident on the photodiode 21 while the selection transistor 24 is ON, an avalanche current is generated in the photodiode 21. This causes the avalanche current to flow through the quench resistor 23, and the voltage at connection point N1 rises. When the voltage at connection point N1 becomes higher than the ON voltage of the NMOS transistor 252, the NMOS transistor 252 turns ON, and the voltage at connection point N2 changes from the power supply voltage VDD to 0V. Then, when the voltage at connection point N2 changes from the power supply voltage VDD to 0V, the PMOS transistor 261 changes from the OFF state to the ON state, and the NMOS transistor 262 changes from the ON state to the OFF state, and the voltage at connection point N3 changes from 0V to the power supply voltage VDD. As a result, a high-level detection signal V_OUT is output from the buffer 27.

[0043] Subsequently, as the voltage at connection point N1 continues to rise, the voltage applied between the anode and cathode of the photodiode 21 becomes less than the breakdown voltage, causing the avalanche current to stop and the voltage at connection point N1 to drop. When the voltage at connection point N1 becomes lower than the on-voltage of the NMOS transistor 252, the NMOS transistor 252 turns off, and the output of the detection signal V_OUT from buffer 27 stops (becomes low level).

[0044] Thus, the readout circuit 22 outputs a high-level detection signal V_OUT during the period from when a photon is incident on the photodiode 21, generating an avalanche current and turning on the NMOS transistor 252, until when the avalanche current stops and the NMOS transistor 252 turns off. The output detection signal V_OUT is input to the SPAD adder 40 for each macro pixel 30 via the output circuit 145. Therefore, each SPAD adder 40 receives a detection signal V_OUT equal to the number of SPAD pixels 20 (detection count) in which a photon incident was detected among the multiple SPAD pixels 20 constituting one macro pixel 30.

[0045] 1.7 SPAD Addition Section Figure 6 is a block diagram showing a more detailed configuration example of the SPAD adder according to this embodiment. Note that the SPAD adder 40 may be included in the light receiving unit 14 or in the calculation unit 15.

[0046] As shown in Figure 6, the SPAD summing unit 40 includes, for example, a pulse shaping unit 41 and a light reception count unit 42.

[0047] The pulse shaping unit 41 shapes the pulse waveform of the detection signal V_OUT input from the SPAD array 141 via the output circuit 145 into a pulse waveform with a time width corresponding to the operating clock of the SPAD adder 40.

[0048] The light-receiving count unit 42 counts the number of SPAD pixels 20 in which photon incidence is detected (detection count) at each sampling period by counting the detection signal V_OUT input from the corresponding macro pixels 30, and outputs this count value as the pixel value of the macro pixels 30.

[0049] 1.8 Sampling Period Here, the sampling period is the period for measuring the time (time of flight) from when the light-emitting unit 13 emits laser light L1 until the photon incident is detected by the light-receiving unit 14. This sampling period is set to be shorter than the emission period of the light-emitting unit 13. For example, by making the sampling period shorter, it becomes possible to calculate the time of flight of photons emitted from the light-emitting unit 13 and reflected by the object 90 with higher temporal resolution. This means that by making the sampling frequency higher, it becomes possible to calculate the distance to the object 90 with higher ranging resolution.

[0050] For example, if we consider the time t as the flight time from when the light-emitting unit 13 emits laser light L1, when this laser light L1 is reflected by object 90, until this reflected light L2 enters the light-receiving unit 14, then since the speed of light C is constant (C ≈ 300,000,000 m (meters) / s (seconds)), the distance L to object 90 can be calculated using the following equation (1). L = C × t / 2 (1)

[0051] Therefore, if the sampling frequency is set to 1 GHz, the sampling period becomes 1 ns (nanosecond). In this case, one sampling period corresponds to 15 cm (centimeter). This indicates that the distance measurement resolution is 15 cm when the sampling frequency is 1 GHz. Furthermore, if the sampling frequency is doubled to 2 GHz, the sampling period becomes 0.5 ns (nanosecond), so one sampling period corresponds to 7.5 cm (centimeter). This indicates that the distance measurement resolution can be halved by doubling the sampling frequency. In this way, by increasing the sampling frequency and shortening the sampling period, it becomes possible to calculate the distance to object 90 with greater accuracy.

[0052] 1.9 Histogram Figure 7 shows the histogram generated by the calculation unit 15 described above. Specifically, Figure 7 shows a linearized histogram with the vertical axis representing cumulative pixel values ​​and the horizontal axis representing time (time of flight). As shown in Figure 7, when an object 90 (see Figure 1) is present in the area detected by the ToF sensor 1, a peak P1 corresponding to the reflecting object 90 appears in the histogram. This peak P1 has a peak width close to the pulse width of the laser light L1.

[0053] 1.10 Area to detect Figure 8 illustrates the areas detected by the LD array and SPAD array. As shown in Figure 8, the ToF sensor 1 is installed on a mobile body 100, such as a vehicle. The sets of LDs 131-1 to 131-8 and SPAD regions 142-1 to 142-8 shown in Figure 4 are used to measure the distance of areas A1 to A8, respectively. In other words, the LDs 131-1 to 131-8 of the LD array 131 emit light at different angles along the vertical direction, and the SPAD regions 142-1 to 142-8 of the SPAD array 142 receive light from different angles along the vertical direction.

[0054] Specifically, LD131-1 emits laser light toward region A1, and SPAD region 142-1 receives the reflected light from region A1. Similarly, LD131-2 emits laser light toward region A2, and SPAD region 142-2 receives the reflected light from region A3. LD131-3 to LD131-8 similarly emit laser light toward regions A3 to A8, and SPAD regions 142-3 to LD142-8 similarly receive the reflected light from regions A3 to A8. In other words, LD131-4 and 131-5 emit light in the direction with the smallest angle to the horizontal, LD131-3 and 131-6 emit light in the direction with the next smallest angle to the horizontal after LD131-4 and 131-5, LD131-2 and 131-7 emit light in the direction with the next smallest angle to the horizontal after LD131-3 and 131-6, and LD131-1 and 131-8 emit light in the direction with the largest angle to the horizontal.

[0055] Here, if the ToF sensor 1 is installed on a moving object 100, which is a vehicle, then regions A4 and A5 correspond to the front of the moving object 100, and therefore require measurement of distances to objects several tens to several hundreds of meters away, resulting in a large required detection distance LA1. On the other hand, in regions A1 and A8, there is no need to measure the sky or the ground, so the required detection distance LA4 is small. Thus, the required detection distances LA1 in regions A4 and A5, LA2 in regions A3 and A6, LA3 in regions A2 and A7, and LA4 in regions A1 and A8 decrease in this order.

[0056] 1.11 Number of detections In regions A4 and A5 shown in Figure 8, the required detection distance LA1 is large, which may result in the object 90 being far away. When the object 90 is far away, the light intensity of the peak P1 due to reflected light L2, as shown in Figure 7, is smaller than when the object 90 is close. If the light intensity of the peak P1 is small and is obscured by ambient light, accurate distance measurement may not be possible. Ambient light here refers to light originating from the surrounding environment, such as sunlight.

[0057] The control unit 11 controls the number of measurements to increase as the distance to be detected increases. By increasing the number of measurements and integrating the detection results, the light intensity of the peak P1 can be increased, preventing the peak P1 caused by reflected light L2 from being obscured by ambient light, and enabling accurate distance measurement.

[0058] Specifically, the control unit 11 uses the height from the ground to the installation position of the ToF sensor 1 and the installation angle relative to the horizontal to the ground to calculate the distances LA1 to LA4 required for detection in regions A1 to A8 corresponding to the direction in which LD131-1 to 131-8 emit light. Then, the control unit 11 determines the number of measurements according to the distances LA1 to LA4 required for detection.

[0059] Figure 4 shows an example of the number of measurements determined by the control unit 11. The control unit 11 controls the number of light emission cycles for LD131-1 to 131-8 and the number of light reception cycles for SPAD regions 142-1 to 142-8 to match the number of measurements. In regions A4 and A5, where the detection distance LA1 is largest, the control unit 11 determines the number of measurements (i.e., the number of light emission cycles and the number of light reception cycles) to be 6. Similarly, in order of increasing detection distance, the control unit 11 determines the number of measurements to be 3 for regions A3 and A6, 2 for regions A2 and A7, and 1 for regions A1 and A8. The total number of measurements is preferably set by determining the number of light emission cycles based on the upper limit of the laser safety standard, for example, 24.

[0060] Furthermore, by appropriately selecting the light emission intensity in the light-emitting unit 13, distance measurement can be performed with high accuracy. Figure 9 is a diagram showing the relationship between the measurement distance and the light emission intensity. In Figure 9, the horizontal axis represents the measurable distance, and the vertical axis represents the light emission intensity of the light-emitting unit 13. Due to the inverse square law of light attenuation, when measuring distances further, it is necessary to increase the light emission intensity. Figure 10 is a diagram showing the relationship between the measurement distance, the light emission intensity, and the number of measurements. In Figure 10, the number of measurements required to accurately measure distances at each measurement distance and each light emission intensity is shown numerically. As shown in Figure 10, when the light emission intensity in the light-emitting unit 13 is weak, accurate distance measurement can be performed by increasing the number of measurements and accumulating them multiple times. On the other hand, if the light emission intensity is increased, accurate distance measurement can be performed even with fewer measurements, but in the region where the distance to be measured is close, the light-receiving element of the light-receiving unit 14 may become saturated, making accurate measurement impossible. Therefore, it is preferable to appropriately select the light emission intensity in the light-emitting unit 13 to perform high-precision distance measurement.

[0061] The control unit 11 may determine the number of flashes depending on the position where the ToF sensor 1 is installed. Figures 9 and 10 show the installation positions of the ToF sensor according to modified examples 1 and 2. As shown in Figure 9, if the ToF sensor 1 is installed below the mobile body 100 and the height from the ground to the installation position of the ToF sensor 1 is small, the number of flashes may be decreased in the order of regions A12, A13, and A14, starting from the uppermost region A11. Similarly, as shown in Figure 10, if the ToF sensor 1 is installed above the mobile body 100 and the height from the ground to the installation position of the ToF sensor 1 is large, the number of flashes may be decreased in the order of regions A22, A24, and A21, starting from the second lowest region A23.

[0062] Furthermore, the control unit 11 may determine the number of flashes according to the speed at which the moving object 100 on which the ToF sensor 1 is installed is moving. For example, when the moving object 100 is moving at high speed, the control unit 11 controls the number of flashes in the forward areas A4 and A5 to increase in order to measure the distance to objects located above the moving object 100, such as signs and ceilings.

[0063] Furthermore, the control unit 11 may determine the number of flashes according to the position information of the mobile body 100 on which the ToF sensor 1 is installed. For example, if the position of the mobile body 100 indicated by the position information is on a slope, the control unit 11 may determine the number of flashes in areas A1 to A8 according to the slope. The control unit 11 acquires position information including the latitude, longitude, and altitude of the vehicle generated when the mobile body 100 receives GNSS signals from GNSS (Global Navigation Satellite System) satellites (for example, GPS signals from GPS (Global Positioning System) satellites) and performs positioning.

[0064] Next, we will explain the processing procedure performed by the ToF sensor 1 using Figure 13. Figure 13 is a flowchart showing the overall processing procedure performed by the ToF sensor 1.

[0065] As shown in Figure 13, the control unit 11 determines the number of measurements in regions A1 to A8 (step S101). Specifically, as shown in Figure 4, the control unit 11 determines the number of measurements in regions A1 to A8.

[0066] Next, the light-emitting unit 13 emits laser light L1 by emitting light (step S102).

[0067] Then, the light receiving unit 14 receives the reflected light L2 that is formed when the laser light L1 is reflected by the object 90 (step S103).

[0068] Subsequently, the calculation unit 15 generates a histogram of cumulative pixel values ​​based on the detection signal output from the light receiving unit 14 (step S104).

[0069] Then, the control unit 11 calculates the distance to object 90 based on the generated histogram (step S105).

[0070] Next, the control unit 11 outputs the calculated distance to the host 80 (step S106) and terminates the process.

[0071] 2. Application Examples The technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile vehicle, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, or agricultural machinery (tractors).

[0072] Figure 14 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile control system to which the technology described herein can be applied. The vehicle control system 7000 comprises a plurality of electronic control units connected via a communication network 7010. In the example shown in Figure 14, the vehicle control system 7000 comprises a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an external information detection unit 7400, an internal information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these plurality of control units may be an in-vehicle communication network conforming to any standard such as CAN (Controller Area Network), LIN (Local Interconnect Network), LAN (Local Area Network), or FlexRay®.

[0073] Each control unit comprises a microcomputer that performs calculations according to various programs, a storage unit that stores programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various controlled devices. Each control unit is equipped with a network interface for communication with other control units via the communication network 7010, and a communication interface for communication with devices or sensors inside or outside the vehicle via wired or wireless communication. Figure 14 illustrates the functional configuration of the integrated control unit 7600, which includes a microcomputer 7610, a general-purpose communication interface 7620, a dedicated communication interface 7630, a positioning unit 7640, a beacon receiver 7650, an in-vehicle equipment interface 7660, an audio / image output unit 7670, an in-vehicle network interface 7680, and a storage unit 7690. Other control units similarly include a microcomputer, a communication interface, and a storage unit.

[0074] The drivetrain control unit 7100 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 7100 functions as a control device for generating driving force for the vehicle, such as an internal combustion engine or a drive motor; a driving force transmission mechanism for transmitting driving force to the wheels; a steering mechanism for adjusting the steering angle of the vehicle; and a braking device for generating braking force for the vehicle. The drivetrain control unit 7100 may also function as a control device such as ABS (Antilock Brake System) or ESC (Electronic Stability Control).

[0075] A vehicle state detection unit 7110 is connected to the drivetrain control unit 7100. The vehicle state detection unit 7110 includes, for example, a gyro sensor for detecting the angular velocity of the vehicle's axial rotational motion, an acceleration sensor for detecting the vehicle's acceleration, or at least one of the sensors for detecting the amount of operation of the accelerator pedal, the amount of operation of the brake pedal, the steering angle of the steering wheel, the engine speed, or the rotational speed of the wheels. The drivetrain control unit 7100 performs calculations using signals input from the vehicle state detection unit 7110 and controls the internal combustion engine, drive motor, electric power steering system, brake system, etc.

[0076] The body system control unit 7200 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 7200 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0077] The battery control unit 7300 controls the secondary battery 7310, which is the power source for the drive motor, according to various programs. For example, the battery control unit 7300 receives information such as battery temperature, battery output voltage, or remaining battery capacity from the battery device equipped with the secondary battery 7310. The battery control unit 7300 uses these signals to perform calculations and controls the temperature of the secondary battery 7310 or the cooling device provided in the battery device.

[0078] The external information detection unit 7400 detects information from outside the vehicle equipped with the vehicle control system 7000. For example, at least one of the imaging unit 7410 and the external information detection unit 7420 is connected to the external information detection unit 7400. The imaging unit 7410 includes at least one of the following: a ToF (Time Of Flight) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The external information detection unit 7420 includes at least one of the following: an environmental sensor for detecting the current weather or climate, or an ambient information detection sensor for detecting other vehicles, obstacles, or pedestrians around the vehicle equipped with the vehicle control system 7000.

[0079] The environmental sensor may be at least one of the following: a raindrop sensor for detecting rain, a fog sensor for detecting fog, a sunshine sensor for detecting the degree of sunlight, and a snow sensor for detecting snowfall. The ambient information detection sensor may be at least one of the following: an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. These imaging unit 7410 and external information detection unit 7420 may be provided as independent sensors or devices, or as a device in which multiple sensors or devices are integrated.

[0080] Here, Figure 15 shows examples of the installation locations of the imaging unit 7410 and the external information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are installed, for example, at least one of the following locations on the vehicle 7900: the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the passenger compartment. The imaging unit 7910 installed on the front nose and the imaging unit 7918 installed on the upper part of the windshield inside the passenger compartment mainly acquire images of the front of the vehicle 7900. The imaging units 7912 and 7914 installed on the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 installed on the upper part of the windshield inside the passenger compartment is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0081] Figure 15 shows an example of the imaging range of each imaging unit 7910, 7912, 7914, and 7916. Imaging range a shows the imaging range of imaging unit 7910 located on the front nose, imaging ranges b and c show the imaging ranges of imaging units 7912 and 7914 located on the side mirrors, respectively, and imaging range d shows the imaging range of imaging unit 7916 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 7910, 7912, 7914, and 7916, an overhead view image of the vehicle 7900 can be obtained.

[0082] The external information detection units 7920, 7922, 7924, 7926, 7928, and 7930, which are installed on the front, rear, sides, corners, and the upper part of the windshield inside the vehicle 7900, may be, for example, ultrasonic sensors or radar devices. The external information detection units 7920, 7926, and 7930, which are installed on the front nose, rear bumper, back door, and the upper part of the windshield inside the vehicle 7900, may be, for example, LIDAR devices. These external information detection units 7920 to 7930 are mainly used to detect preceding vehicles, pedestrians, or obstacles.

[0083] Returning to Figure 14, the explanation continues. The external information detection unit 7400 causes the imaging unit 7410 to capture images of the area outside the vehicle and receives the captured image data. The external information detection unit 7400 also receives detection information from the connected external information detection unit 7420. If the external information detection unit 7420 is an ultrasonic sensor, radar device, or LIDAR device, the external information detection unit 7400 emits ultrasonic waves or electromagnetic waves and receives information on the received reflected waves. Based on the received information, the external information detection unit 7400 may perform object detection processing such as detecting people, vehicles, obstacles, signs, or characters on the road surface, or distance detection processing. Based on the received information, the external information detection unit 7400 may perform environmental recognition processing to recognize rainfall, fog, or road surface conditions. Based on the received information, the external information detection unit 7400 may calculate the distance to an object outside the vehicle.

[0084] Furthermore, the external information detection unit 7400 may perform image recognition processing or distance detection processing to recognize people, vehicles, obstacles, signs, or characters on the road surface based on the received image data. The external information detection unit 7400 may perform distortion correction or alignment processing on the received image data, and may also synthesize image data captured by different imaging units 7410 to generate an overhead view image or a panoramic image. The external information detection unit 7400 may also perform viewpoint transformation processing using image data captured by different imaging units 7410.

[0085] The in-vehicle information detection unit 7500 detects information inside the vehicle. The in-vehicle information detection unit 7500 is connected to, for example, a driver status detection unit 7510 that detects the driver's state. The driver status detection unit 7510 may include a camera that images the driver, a biosensor that detects the driver's biometric information, or a microphone that collects sounds inside the vehicle. The biosensor is installed, for example, on the seat or steering wheel and detects the biometric information of a passenger sitting in the seat or a driver holding the steering wheel. Based on the detection information input from the driver status detection unit 7510, the in-vehicle information detection unit 7500 may calculate the driver's level of fatigue or concentration, or determine whether the driver is dozing off. The in-vehicle information detection unit 7500 may perform processing such as noise cancellation on the collected audio signals.

[0086] The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 according to various programs. An input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 is implemented by a device that can be operated by the passenger, such as a touch panel, buttons, a microphone, a switch, or a lever. The integrated control unit 7600 may also receive data obtained by voice recognition of voice input from the microphone. The input unit 7800 may be a remote control device using infrared or other radio waves, or an external device such as a mobile phone or PDA (Personal Digital Assistant) that is compatible with the operation of the vehicle control system 7000. The input unit 7800 may be a camera, in which case the passenger can input information by gesture. Alternatively, data obtained by detecting the movement of a wearable device worn by the passenger may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on the information input by the passenger using the above input unit 7800 and outputs it to the integrated control unit 7600. Passengers and others can input various data or instruct the vehicle control system 7000 to perform processing operations by operating this input unit 7800.

[0087] The memory unit 7690 may include a ROM (Read Only Memory) for storing various programs executed by a microcomputer, and a RAM (Random Access Memory) for storing various parameters, calculation results, or sensor values. The memory unit 7690 may also be implemented using a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device.

[0088] The general-purpose communication interface 7620 is a general-purpose communication interface that mediates communication between the vehicle and various devices present in the external environment 7750. The general-purpose communication interface 7620 may implement cellular communication protocols such as GSM (Global System of Mobile communications), WiMAX (registered trademark), LTE (registered trademark) (Long Term Evolution), or LTE-A (LTE-Advanced), or other wireless communication protocols such as wireless LAN (also known as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general-purpose communication interface 7620 may connect to devices (e.g., application servers or control servers) located on an external network (e.g., the Internet, a cloud network, or a carrier-specific network) via, for example, a base station or access point. The general-purpose communication interface 7620 may also connect to terminals located near the vehicle (e.g., terminals for drivers, pedestrians, or shops, or MTC (Machine Type Communication) terminals) using, for example, P2P (Peer To Peer) technology.

[0089] The Dedicated Communication I / F 7630 is a communication interface that supports communication protocols developed for use in vehicles. The Dedicated Communication I / F 7630 may implement standard protocols such as WAVE (Wireless Access in Vehicle Environment), DSRC (Dedicated Short Range Communications), or cellular communication protocols, which are combinations of lower-layer IEEE 802.11p and upper-layer IEEE 1609. The Dedicated Communication I / F 7630 typically performs V2X communication, a concept that includes one or more of the following: vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0090] The positioning unit 7640 performs positioning by receiving GNSS signals from GNSS (Global Navigation Satellite System) satellites (for example, GPS signals from GPS (Global Positioning System) satellites) and generates location information including the vehicle's latitude, longitude, and altitude. The positioning unit 7640 may also determine its current location by exchanging signals with a wireless access point, or it may acquire location information from a terminal such as a mobile phone, PHS, or smartphone that has a positioning function.

[0091] The beacon receiver 7650 receives radio waves or electromagnetic waves transmitted from, for example, a radio station installed on a road, and obtains information such as the current location, traffic congestion, road closures, or travel time. The functions of the beacon receiver 7650 may also be included in the dedicated communication interface 7630 described above.

[0092] The in-vehicle equipment interface (I / F) 7660 is a communication interface that mediates connections between the microcomputer 7610 and various in-vehicle equipment 7760 located inside the vehicle. The in-vehicle equipment interface (I / F) 7660 may establish a wireless connection using wireless communication protocols such as Wi-Fi, Bluetooth®, NFC (Near Field Communication), or WUSB (Wireless USB). The in-vehicle equipment interface (I / F) 7660 may also establish a wired connection such as USB (Universal Serial Bus), HDMI® (High-Definition Multimedia Interface), or MHL (Mobile High-Definition Link) via connection terminals (and cables if necessary) not shown. The in-vehicle equipment 7760 may include, for example, at least one of the following: a mobile device or wearable device owned by a passenger, or information equipment brought into or installed in the vehicle. The in-vehicle equipment 7760 may also include a navigation device that performs route searching to any destination. The in-vehicle equipment interface 7660 exchanges control signals or data signals with these in-vehicle equipment units 7760.

[0093] The in-vehicle network interface 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network interface 7680 transmits and receives signals and other data in accordance with a predetermined protocol supported by the communication network 7010.

[0094] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information acquired via at least one of the general-purpose communication I / F 7620, dedicated communication I / F 7630, positioning unit 7640, beacon receiver 7650, in-vehicle equipment I / F 7660, and in-vehicle network I / F 7680. For example, the microcomputer 7610 may calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on acquired in-vehicle and out-of-vehicle information and output control commands to the drive system control unit 7100. For example, the microcomputer 7610 may perform coordinated control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning. Furthermore, the microcomputer 7610 may perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on the acquired information about the vehicle's surroundings.

[0095] The microcomputer 7610 may generate three-dimensional distance information between the vehicle and surrounding structures, people, and other objects based on information acquired via at least one of the general-purpose communication I / F 7620, dedicated communication I / F 7630, positioning unit 7640, beacon receiver 7650, in-vehicle equipment I / F 7660, and in-vehicle network I / F 7680, and create local map information including surrounding information of the vehicle's current location. Furthermore, the microcomputer 7610 may predict dangers such as vehicle collision, proximity of pedestrians, or entry into a closed road based on the acquired information, and generate a warning signal. The warning signal may, for example, be a signal to generate a warning sound or illuminate a warning lamp.

[0096] The audio-image output unit 7670 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying the vehicle's occupants or those outside the vehicle. In the example in Figure 14, the output devices are exemplified as an audio speaker 7710, a display unit 7720, and an instrument panel 7730. The display unit 7720 may include, for example, at least one of an onboard display and a head-up display. The display unit 7720 may also have an AR (Augmented Reality) display function. The output device may be other devices besides these, such as headphones, wearable devices such as glasses-type displays worn by occupants, projectors, or lamps. If the output device is a display device, the display device visually displays the results obtained from various processes performed by the microcomputer 7610 or information received from other control units in various formats such as text, images, tables, and graphs. If the output device is an audio output device, the audio output device converts the audio signal, consisting of reproduced audio data or sound data, into an analog signal and outputs it audibly.

[0097] In the example shown in Figure 14, at least two control units connected via the communication network 7010 may be integrated into a single control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include other control units not shown. Also, in the above description, some or all of the functions performed by one control unit may be assigned to other control units. In other words, as long as information is transmitted and received via the communication network 7010, predetermined calculation processing may be performed by any of the control units. Similarly, a sensor or device connected to one control unit may be connected to another control unit, and multiple control units may transmit and receive detection information to each other via the communication network 7010.

[0098] Furthermore, the computer program for realizing each function of the ToF sensor 1 according to this embodiment, as described with reference to Figure 1, can be implemented in any control unit or the like. Alternatively, a computer-readable recording medium containing such a computer program can be provided. Examples of recording media include magnetic disks, optical disks, magneto-optical disks, and flash memory. The computer program may also be distributed, for example, via a network, without using a recording medium.

[0099] In the vehicle control system 7000 described above, the ToF sensor 1 according to this embodiment, as described with reference to Figure 1, can be applied to the integrated control unit 7600 in the application example shown in Figure 14. For example, the control unit 11, calculation unit 15, and external I / F 19 of the ToF sensor 1 correspond to the microcomputer 7610, storage unit 7690, and in-vehicle network I / F 7680 of the integrated control unit 7600. However, it is not limited to this, and the vehicle control system 7000 may correspond to the host 80 in Figure 1.

[0100] Furthermore, at least some of the components of the ToF sensor 1 described using Figure 1 may be implemented in a module for the integrated control unit 7600 shown in Figure 14 (for example, an integrated circuit module consisting of a single die). Alternatively, the ToF sensor 1 described using Figure 1 may be implemented by multiple control units of the vehicle control system 7000 shown in Figure 14.

[0101] 3. Summary As described above, according to one embodiment of the present disclosure, the light source device 2 according to this embodiment comprises a light-emitting unit 13, a scanning unit (drive unit 134 and galvanometer mirror 135), and a control unit 11. The light-emitting unit 13 has a plurality of light-emitting elements arranged along a first direction (vertical direction). The galvanometer mirror 135 is driven by the drive unit 134 and scans the light emitted by the plurality of light-emitting elements along a second direction (horizontal direction) perpendicular to the first direction. The control unit 11 controls the number of times the first group of light-emitting elements included in the plurality of light-emitting elements emits light to be greater than the number of times the second group of light-emitting elements not included in the first group of light-emitting elements emit light. This increases the number of times the light is emitted for important areas along the vertical direction, enabling high-precision measurement.

[0102] Although the embodiments of this disclosure have been described above, the technical scope of this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure. Furthermore, components from different embodiments and modifications may be combined as appropriate.

[0103] Furthermore, the effects described in each embodiment of this specification are merely illustrative and not limiting, and other effects may also occur.

[0104] Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also occur.

[0105] Furthermore, this technology can also be configured as follows. (1) A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A control unit that controls the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more than the number of times a second group of light-emitting elements, which is not included in the first group of light-emitting elements, A light source device equipped with the following features. (2) The light source device according to (1), wherein the control unit controls the number of times the light is emitted as the distance required for detection increases. (3) The light-emitting part is the light source device according to (1) or (2) above, which emits light at different angles along the vertical direction. (4) The light source device according to any one of (1) to (3), wherein the first group of light-emitting elements emits light in a direction that has a smaller angle with respect to the horizontal than the second group of light-emitting elements. (5) The first direction is the vertical direction, The light source device according to any one of (1) to (4) above, wherein the second direction is the horizontal direction. (6) The light source device is a light source device described in any one of (1) to (5) above, which is installed on a mobile body. (7) The control unit determines the number of times the light source is emitted according to the location where the light source device is installed, according to any one of (1) to (6) above. (8) The light source device according to (6) or (7), wherein the control unit determines the number of times the light is emitted according to the speed at which the moving body moves. (9) The control unit determines the number of times the light is emitted according to the position information of the moving body. A light source device as described in any one of (6) to (8) above. (10) A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A control unit that controls the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more than the number of times a second group of light-emitting elements, which is not included in the first group of light-emitting elements, The device comprises a light-receiving unit which has multiple light-receiving elements arranged along the first direction and receives light from each of the multiple light-emitting elements, Ranging device. (11) The control unit, The number of times a light-receiving element receives light from the first group of light-emitting elements is made the same as the number of times the first group of light-emitting elements emits light. The distance measuring device according to (10), which controls the number of times a light-receiving element receives light from the second group of light-emitting elements to be the same as the number of times the second group of light-emitting elements emit light. (12) A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A distance measuring method performed by a distance measuring device comprising a light-receiving unit that receives light from each of the multiple light-emitting elements, wherein a plurality of light-receiving elements are arranged along the first direction, A distance measuring method, comprising a control step of controlling the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more than the number of times a second group of light-emitting elements, which is not included in the first group of light-emitting elements, emits light. (13) The control process described above is: The number of times a light-receiving element receives light from the first group of light-emitting elements is made the same as the number of times the first group of light-emitting elements emits light. The distance measuring method according to (12), wherein control is performed to make the number of times a light-receiving element receives light from the second group of light-emitting elements the same as the number of times the second group of light-emitting elements emits light. [Explanation of symbols]

[0106] 1. ToF sensor (distance measuring device) 2 Light source device 11 Control Unit 13 Light-emitting part 14 Light receiving part 15 Arithmetic section 20 SPAD pixels 30 macro pixels 80 hosts 90 Object

Claims

1. A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A control unit that controls the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more than the number of times a second group of light-emitting elements, which is not included in the first group of light-emitting elements, A light source device equipped with the following features.

2. The light source device according to claim 1, wherein the control unit performs control to increase the number of times light is emitted as the distance required for detection increases.

3. The light-emitting part emits light at different angles along the vertical direction, as described in claim 1.

4. The light source device according to claim 3, wherein the first group of light-emitting elements emits light in a direction that has a smaller angle with respect to the horizontal than the second group of light-emitting elements.

5. The first direction is the vertical direction, The light source device according to claim 1, wherein the second direction is the horizontal direction.

6. The light source device according to claim 1, wherein the light source device is installed on a mobile body.

7. The light source device according to claim 6, wherein the control unit determines the number of times the light source device is illuminated according to the position in which the light source device is installed.

8. The light source device according to claim 6, wherein the control unit determines the number of times the light is emitted according to the speed at which the moving body moves.

9. The light source device according to claim 6, wherein the control unit determines the number of times the light is emitted according to the position information of the moving body.

10. A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A control unit that controls the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more than the number of times a second group of light-emitting elements, which is not included in the first group of light-emitting elements, The device comprises a light-receiving unit which is arranged along the first direction and receives light from each of the multiple light-emitting elements, Ranging device.

11. The control unit, The number of times a light-receiving element receives light from the first group of light-emitting elements is made the same as the number of times the first group of light-emitting elements emits light. The distance measuring device according to claim 10, further comprising the control of a photodetector that receives light from the second group of light-emitting elements to make the number of times it receives light the same as the number of times the second group of light-emitting elements emits light.

12. A light-emitting section in which multiple light-emitting elements are arranged along a first direction, A scanning unit scans the light emitted by the plurality of light-emitting elements along a second direction perpendicular to the first direction, A distance measuring method performed by a distance measuring device comprising a light-receiving unit that receives light from each of the multiple light-emitting elements, wherein a plurality of light-receiving elements are arranged along the first direction, A distance measuring method, comprising a control step of controlling the number of times a first group of light-emitting elements, which is included in the plurality of light-emitting elements, emits light more often than a second group of light-emitting elements, which is not included in the first group of light-emitting elements.

13. The control process described above is: The number of times a light-receiving element receives light from the first group of light-emitting elements is made the same as the number of times the first group of light-emitting elements emits light. The distance measuring method according to claim 12, further comprising controlling the number of times a light-receiving element receives light from the second group of light-emitting elements to be the same as the number of times the second group of light-emitting elements emit light.

Images