Optical signal switching module

Abstract

To fulfill the needs as an optical signal switching module for a lidar.SOLUTION: An optical signal switching module used for a lidar comprises: an optical branch unit 513 that receives input of optical signals from a plurality of light sources, and selectively switches output destinations of the optical signals to one of output destinations of a plurality of channels; a waveguide type crossing unit 515 that crosses at least some optical signals of the plurality of optical signals output from the optical branch unit 513; and output terminals of the plurality of channels that individually output the plurality of optical signals output from the crossing unit 515.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an optical signal switching module for a lidar that measures the detection of an object, the distance to the object, and the like.

Background Art

[0002] LiDAR (Light Detection And Ranging) is known as a key device that supports autonomous driving technology. The lidar scans by changing the irradiation angle of the laser light to be irradiated in two axial directions respectively, and measures the detection of an object, the distance to the object, and the like based on the position information of each detection point. For example, Patent Document 1 discloses a lidar system that operates a wavelength division element such as an optical phased array (OPA) to irradiate laser light on different sample regions within the field of view.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, when a lidar is mounted on an automobile or the like, it is necessary to irradiate laser light to several hundred or more irradiation points per axis. When using the conventional technology, since only a wavelength division element that selectively outputs laser light from one of the two-channel output ends is stacked and the several hundred or more output ends are switched one by one, it is difficult to densely output laser light from a plurality of output ends at the final stage.

Means for Solving the Problems

[0005] An optical signal switching module according to an aspect of the present invention is an optical signal switching module used in a lidar, and includes an optical branching unit that inputs optical signals from a plurality of light sources respectively and selectively switches the output destination of each optical signal to one of the output destinations of a plurality of channels, a waveguide type crossing unit that crosses at least a part of the plurality of optical signals output from the optical branching unit, and a plurality of channel output ends that individually output the plurality of optical signals output from the crossing unit.

Effects of the Invention

[0006] According to the present invention, it becomes possible to satisfy the needs as an optical signal switching module for a lidar.

Brief Description of the Drawings

[0007]

Figure 1A

Figure 1B

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the invention will be described with reference to the drawings. First, an external recognition device using a lidar device (hereinafter referred to as a lidar) as an in-vehicle detector according to an embodiment of the invention and a vehicle equipped with this external recognition device will be described. The external recognition device can be mounted on a vehicle having an automatic driving function, that is, an autonomous vehicle. In the embodiment, the vehicle on which the external recognition device is mounted may be referred to as the host vehicle to distinguish it from other vehicles. The host vehicle may be any of an engine vehicle having an internal combustion engine (engine) as a driving source for traveling, an electric vehicle having a driving motor as a driving source for traveling, and a hybrid vehicle having an engine and a driving motor as driving sources for traveling. The host vehicle can travel not only in an automatic driving mode in which driving operation by a driver is unnecessary but also in a manual driving mode by the driver's driving operation.

[0009] When an autonomous vehicle travels in an automatic driving mode (hereinafter referred to as automatic driving or autonomous driving), it recognizes the external situation around the host vehicle based on detection data from in-vehicle detectors such as a lidar and a camera. Based on the recognition result, the autonomous vehicle generates a driving trajectory (target trajectory) from the current time to a time after a predetermined time and controls a driving actuator so that the host vehicle travels along the target trajectory.

[0010] FIG. 1A is a diagram showing a state in which the host vehicle 101, which is an autonomous vehicle, travels on a road RD. FIG. 1B is a schematic diagram showing an example of detection data obtained by a lidar mounted on the host vehicle 101 and directed in the traveling direction of the host vehicle 101. The measurement points (which may also be called detection points) by the lidar are point information where the irradiated laser is reflected (scattered) at a certain point on the surface of an object and returns. The point information includes the distance from the laser source to that point, the intensity of the laser that has been reflected (scattered) and returned, and the relative velocity between the laser source and that point. Data composed of a plurality of detection points as shown in FIG. 1B is called point cloud data. FIG. 1B shows point cloud data based on the detection points on the surface of an object included in the field of view (hereinafter referred to as FOV) of the lidar among the objects in FIG. 1A. The FOV may be, for example, 120 deg in the horizontal direction (which may also be called the road width direction) of the host vehicle 101 and 25 deg in the vertical direction (which may also be called the up and down direction). The value of the FOV may be appropriately changed based on the specifications of the external recognition device. The host vehicle 101 recognizes the external situation around the vehicle based on the point cloud data as shown in FIG. 1B, more specifically, the road structure and objects around the vehicle, and generates a target trajectory based on the recognition result.

[0011] By the way, as a method of sufficiently recognizing the external situation around the vehicle, it is conceivable to increase the number of irradiation points of the electromagnetic wave irradiated from an in-vehicle detector such as a lidar (in other words, increase the irradiation point density of the electromagnetic wave and increase the number of detection points constituting the point cloud data). On the other hand, increasing the number of irradiation points of the electromagnetic wave (increasing the number of detection points) may increase the processing load for controlling the in-vehicle detector or increase the capacity of the detection data (point cloud data) obtained by the in-vehicle detector, resulting in an increase in the processing load for the point cloud data. In particular, in a situation where many objects exist on or beside the road, the capacity of the point cloud data further increases. Therefore, in consideration of the above points, in the embodiment, an external recognition device is configured as follows.

[0012] <Summary> The external recognition device equipped with a lidar according to the embodiment intermittently irradiates light for irradiation, which is an example of electromagnetic waves, in the traveling direction of the host vehicle 101 from the lidar of the host vehicle 101 traveling on the road RD, and discretely acquires point cloud data at different positions on the road RD. The irradiation range of the irradiation light irradiated from the lidar is set so that there is no blank interval in the data in the traveling direction of the road RD between the point cloud data of the previous frame acquired by the lidar in the previous irradiation and the point cloud data of the next frame acquired by the lidar in the current irradiation. The detection point density within the irradiation range is set, for example, to be high for the road surface far from the host vehicle 101 and low for the road surface close to the host vehicle 101. Compared with the case of setting a high detection point density for all road surfaces within the irradiation range, the total number of detection points used for the recognition process is suppressed. As a result, it becomes possible to reduce the number of detection points used for the recognition process without degrading the recognition accuracy of the position (distance from the host vehicle 101) and size of an object or the like recognized based on the point cloud data. Such an external recognition device will be described in more detail.

[0013] <Configuration of Vehicle Control Device> FIG. 2 is a block diagram showing a main configuration of a vehicle control device 100 including an external recognition device. This vehicle control device 100 includes a controller 10, a communication unit 1, a positioning unit 2, an internal sensor group 3, a camera 4, a lidar 5, and a traveling actuator AC. The vehicle control device 100 also includes an external recognition device 50 that forms part of the vehicle control device 100. The external recognition device 50 recognizes the external situation around the vehicle based on the detection data of in-vehicle detectors such as the camera 4 and the lidar 5.

[0014] The communication unit 1 communicates with various servers (not shown) via a network including a wireless communication network typified by the Internet or a mobile phone network, and periodically or at any arbitrary timing acquires map information, driving history information, traffic information, etc. from the servers. The network includes not only a public wireless communication network but also a closed communication network provided for each predetermined management area, such as a wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc. The acquired map information is output to the storage unit 12, and the map information is updated. The positioning unit (GNSS unit) 2 has a positioning sensor that receives a positioning signal transmitted from a positioning satellite. The positioning satellite is an artificial satellite such as a GPS satellite or a quasi-zenith satellite. The positioning unit 2 measures the current position (latitude, longitude, altitude) of the host vehicle 101 using the positioning information received by the positioning sensor.

[0015] The internal sensor group 3 is a general term for a plurality of sensors (internal sensors) that detect the driving state of the host vehicle 101. For example, the internal sensor group 3 includes a vehicle speed sensor that detects the vehicle speed (driving speed) of the host vehicle 101, acceleration sensors that respectively detect the acceleration in the front-rear direction and the acceleration in the left-right direction (lateral acceleration) of the host vehicle 101, a rotation speed sensor that detects the rotation speed of the driving power source, a yaw rate sensor that detects the rotational angular velocity of the center of gravity of the host vehicle 101 around the vertical axis, etc. The internal sensor group 3 also includes sensors that detect the driving operations of the driver in the manual driving mode, such as the operation of the accelerator pedal, the operation of the brake pedal, the operation of the steering wheel, etc.

[0016] The camera 4 has an imaging element such as a CCD or a CMOS and images the periphery (front, rear, and sides) of the host vehicle 101. The lidar 5 receives scattered light with respect to the irradiated light and measures the distance from the host vehicle 101 to surrounding objects, the positions of the objects, the shapes, etc.

[0017] Actuator AC is a driving actuator for controlling the running of the host vehicle 101. When the driving power source is an engine, actuator AC includes a throttle actuator for adjusting the opening degree (throttle opening degree) of the throttle valve of the engine. When the driving power source is a driving motor, the driving motor is included in actuator AC. Actuator AC also includes a brake actuator for operating the braking device of the host vehicle 101 and a steering actuator for driving the steering device.

[0018] Controller 10 is constituted by an electronic control unit (ECU). More specifically, controller 10 includes a computer having an arithmetic unit 11 such as a CPU (microprocessor), a storage unit 12 such as a ROM and a RAM, and other peripheral circuits (not shown) such as an I / O interface. Although a plurality of ECUs with different functions such as an engine control ECU, a driving motor control ECU, and a braking device ECU can be provided separately, in FIG. 2, for the sake of convenience, controller 10 is shown as a set of these ECUs.

[0019] The storage unit 12 can store highly accurate and detailed map information (referred to as highly accurate map information). The highly accurate map information includes road position information, road shape (curvature, etc.) information, road gradient information, intersection and branch point position information, number of lanes (driving lanes) information, lane width and position information for each lane (information on the center position of the lane and the boundary lines of the lane positions), position information of landmarks (traffic lights, signs, buildings, etc.) as marks on the map, and road surface profile information such as road surface unevenness. In addition to the two-dimensional map information described later, the storage unit 12 can also store various control programs, information such as thresholds used in the programs, and setting information for in-vehicle detectors such as the lidar 5 (including the steering information of the irradiation light described later). Note that since highly accurate and detailed map information is not necessarily required in the embodiment, the detailed map information does not have to be stored in the storage unit 12.

[0020] The arithmetic unit 11 includes, as functional components, a recognition unit 111, a setting unit 112, a determination unit 113, and a travel control unit 114. As shown in FIG. 2, the recognition unit 111, the setting unit 112, and the determination unit 113 are included in the external recognition device 50. As described above, the external recognition device 50 recognizes the external situation around the vehicle based on the detection data of in-vehicle detectors such as the camera 4 and the lidar 5. Details of the recognition unit 111, the setting unit 112, and the determination unit 113 included in the external recognition device 50 will be described later.

[0021] In the automatic driving mode, the travel control unit 114 generates a target trajectory based on the external situation around the vehicle recognized by the external recognition device 50, and controls the actuator AC so that the host vehicle 101 travels along the target trajectory. In the manual driving mode, the travel control unit 114 controls the actuator AC according to a travel command (such as a steering operation) from the driver acquired by the internal sensor group 3.

[0022] The lidar 5 will be further described. <Detection area> The lidar 5 is mounted facing forward of the host vehicle 101 so as to include the area to be gazed at during travel in the FOV. Since the lidar 5 receives light scattered by a three-dimensional object or the like irradiated with irradiation light (hereinafter sometimes referred to as return light), the FOV of the lidar 5 corresponds to the irradiation range of the irradiation light and the detection area. That is, the irradiation point within the irradiation range corresponds to the detection point within the detection area. In the embodiment, three-dimensional objects and the like include the road surface shape including unevenness, steps, undulations, etc. of the road surface, three-dimensional objects located on the road RD (facilities related to the road RD (traffic lights, signs, ditches, walls, fences, guardrails, etc.)), objects on the road RD (including other vehicles and road surface obstacles), and lane lines provided on the road surface. The lane lines include white lines (including lines of different colors such as yellow), curb lines, road studs, etc., and may be referred to as lane marks. Also, those among the three-dimensional objects and the like that are set in advance as detection targets are called detection targets.

[0023] <Irradiation point of irradiation light> FIG. 3 is a schematic diagram for explaining the irradiation points of the irradiation light irradiated within the FOV by the lidar 5. The lidar 5 moves the position of the irradiation point by changing the projection angle of the irradiation light in the vertical direction and the horizontal direction. In the embodiment, the amount of change in the projection angle corresponding to the minimum value of the movement interval of the irradiation point will be referred to as the angular resolution.

[0024] Among the three-dimensional coordinates composed of the x-axis, y-axis, and z-axis, the traveling direction of the host vehicle 101 is made to correspond to the positive x-axis direction, the left in the horizontal direction of the host vehicle 101 is made to correspond to the positive y-axis direction, and the upward in the vertical direction is made to correspond to the positive z-axis direction, respectively. The x-axis component of the position of the detection point at this time is called the depth distance X, the y-axis component of the position of the detection point is called the horizontal distance Y, and the z-axis component of the position of the detection point is called the height Z. Generally, the larger the size of the detection target and the shorter the depth distance X from the host vehicle 101 to the detection target (in other words, the closer the detection target is to the host vehicle 101), the larger the viewing angle with respect to the detection target. Therefore, even if the angular resolution of the lidar 5 is set to be somewhat low, it is possible to detect the detection target. On the contrary, the smaller the size of the detection target and the longer the depth distance X (in other words, the farther the detection target is from the host vehicle 101), the smaller the viewing angle with respect to the detection target. Therefore, unless the angular resolution of the lidar 5 is set to be somewhat high, it becomes difficult to detect the detection target. Therefore, the external recognition device 50 decreases (increases the numerical value) the angular resolution of the lidar 5 as the size of the detection target is larger and the depth distance X is shorter, and increases (decreases the numerical value) the angular resolution of the lidar 5 as the size of the detection target is smaller and the depth distance X is longer. By increasing the angular resolution in the vertical direction, the interval between the irradiation points in the vertical direction within the FOV becomes narrower, the interval between the irradiation points becomes denser, and the number of irradiation points increases. Conversely, by decreasing the angular resolution in the vertical direction, the interval between the irradiation points in the vertical direction within the FOV becomes wider, the interval between the irradiation points becomes coarser, and the number of irradiation points decreases. The same applies to the angular resolution in the horizontal direction.

[0025] In FIG. 3, "dense" indicates the vertical interval of irradiation points (detection points) corresponding to an angular resolution of, for example, 0.05 deg. "Medium" indicates the vertical interval of irradiation points (detection points) corresponding to an angular resolution of, for example, 0.1 deg. "Coarse" indicates the vertical interval of irradiation points (detection points) corresponding to an angular resolution of, for example, 0.2 deg. In FIG. 3, an example of switching the angular resolution in three steps is shown. However, the angular resolution may be configured to be switched as appropriate, not limited to three steps, but two steps or four steps are also acceptable.

[0026] The external recognition device 50 determines the required angular resolution based on, for example, the minimum size of a detection target specified in advance (e.g., 15 cm) and the required depth distance (e.g., 100 m). The required depth distance corresponds to the braking distance of the host vehicle 101 that changes according to the vehicle speed. In the embodiment, based on the idea that the host vehicle 101 during traveling should detect the road surface condition of the road in the traveling direction at least up to the braking distance, a value obtained by adding a predetermined margin to the braking distance is referred to as the required depth distance. The vehicle speed of the host vehicle 101 is detected by software processing such as SLAM using sensor data from the vehicle speed sensor of the internal sensor group 3 or sensors such as the lidar 5. The relationship between the vehicle speed and the required depth distance is stored in the storage unit 12 in advance. When the external recognition device 50 obtains the detected speed from the vehicle speed sensor, it refers to the storage unit 12 to obtain the required depth distance corresponding to the vehicle speed.

[0027] When the host vehicle 101 is traveling in, for example, the autonomous driving mode, the external recognition device 50 sets irradiation points with different intervals (in other words, irradiation points with different coarseness) for each region within the FOV, and controls the lidar 5 to sequentially irradiate these irradiation points with irradiation light. As a result, the irradiation light from the lidar 5 is irradiated toward the set irradiation points (detection points). The external recognition device 50 stores in the storage unit 12 information indicating the positions of the set irradiation points (which may be called steering information of the irradiation light) in association with the position information indicating the traveling position of the host vehicle 101 during traveling.

[0028] For example, when detecting a detection target of 15 cm located 100 m ahead from the host vehicle 101 traveling at a vehicle speed of 100 km / h, the required angular resolution is approximately 0.05 deg. When detecting a detection target with a size smaller than 15 cm, or when detecting a 15 cm detection target at a depth distance X longer than 100 m, it is necessary to further increase the angular resolution to narrow the interval between the irradiation points within the FOV. Conversely, when detecting a detection target with a size larger than 15 cm, or when detecting a 15 cm detection target at a depth distance X shorter than 100 m, it is also possible to further decrease the angular resolution to widen the interval between the irradiation points within the FOV.

[0029] Note that the actual number of irradiation points within the FOV is much larger than the number of black circles shown in FIG. 3. For example, when the FOV of the lidar 5 is 120 deg in the horizontal direction, the black circles corresponding to the irradiation points (detection points) in the horizontal direction line up a maximum of 1200 when the angular resolution is set to 0.1 deg over the entire horizontal range. Similarly, when the FOV is 25 deg in the vertical direction, the black circles corresponding to the irradiation points (detection points) in the vertical direction line up a maximum of 500 when the angular resolution is set to 0.05 deg over the entire vertical range.

[0030] The external recognition device 50 suppresses the total number of irradiation points (detection points), in other words, the total number of detection data used for the recognition process, by controlling the interval between the detection points. Specifically, in a region within the FOV where the depth distance X is shorter than the required depth distance, since the viewing angle with respect to the detection target becomes larger as described above, the intervals between the detection points in the vertical and horizontal directions are widened to suppress the number of irradiation points. Also, for the region within the FOV corresponding to the sky, since there is no detection target such as the road RD, the intervals between the irradiation points in the vertical and horizontal directions are widened to suppress the number of irradiation points. In this way, in the lidar 5 as an in-vehicle detector, although there is little need to set the maximum angular resolution over the entire horizontal and vertical ranges within the FOV (in other words, to set the maximum number of irradiation points by making the interval between the irradiation points dense over the entire FOV), there is a high need to set the maximum angular resolution in any region within the FOV.

[0031] Each time the external recognition device 50 scans the irradiation light for one frame with respect to the FOV, it performs steering control on the irradiation direction of the irradiation light of the lidar 5 in the vertical direction and the horizontal direction respectively, obtains the detection data of the detection points indicated by the black circles in FIG. 3, and obtains point cloud data as shown in FIG. 1B.

[0032] <Steering mechanism of irradiation light> The lidar 5 according to the embodiment includes a mechanical scanning mechanism as a horizontal scanning mechanism for changing the projection angle in the horizontal direction, and a solid-state scanning mechanism as a vertical scanning mechanism for changing the projection angle in the vertical direction.

[0033] FIG. 4 is a schematic diagram illustrating the configuration of the lidar 5. The lidar 5 includes, for example, a transceiver 51 of an FMCW (Frequency Modulated Continuous Wave) system, a vertical scanning mechanism 52, a horizontal scanning mechanism 53, and a control unit 54. The control unit 54 performs signal transmission and reception between the lidar 5 and the controller 10, and controls the transceiver 51, the vertical scanning mechanism 52, and the horizontal scanning mechanism 53. The transceiver 51 includes a light source 511 and a detector 512. In the lidar 5, the solid line arrow indicates the light transmission path, and the broken line arrow indicates the light reception path.

[0034] <Vertical scanning mechanism> FIG. 5 is a block diagram for more detailed explanation of the transceiver 51 and the vertical scanning mechanism 52 of the lidar 5 in FIG. 4. The vertical scanning mechanism 500 including the transceiver includes a light source 511, a balanced photodiode (hereinafter referred to as BPD (Balanced Photodiode)) 512, a first switch group 513, a waveguide intersection 515, a second switch group 516, and a projection lens 525.

[0035] The light source 511 is a P-channel laser light source having a plurality (P) of lasers that emit irradiation light to be sent to the measurement points within the FOV. Each of the P lasers can emit irradiation light either at the same timing or at individual timings. The light source 511 may include an amplifier (amp) that amplifies the light emitted by the laser light source. Further, it may include a splitter that distributes the light emitted by the laser light source into a plurality. The amplifier is effective for outputting irradiation light of a predetermined level to each channel when the power of the light of each laser of the light source 511 is small, and when the power of the light decreases by distributing the light into a plurality of channels.

[0036] The BPD 512 is an optical receiver that detects an interference signal between the reference light and the return light using two photodiodes with uniform characteristics. In the embodiment, this optical receiver is provided with P sets, which is the same number as the number of laser light sources of the light source 511. That is, it is configured to be able to receive the P-channel return light simultaneously.

[0037] The first switch group 513 is an optical switch group having a P-channel input end and a Q (= P × n)-channel output end. For example, it is provided with P 1×n switches that selectively output the optical signals (hereinafter simply referred to as light) input from each input end to any one of n output destinations. Thereby, the P-channel light input from the light source 511 is selectively output from the P-channel output end among the Q-channel output ends. Note that n may be odd or even. The first switch group 513 is configured by combining a plurality of optical switches such as Mach-Zehnder interference type optical switches as will be described later.

[0038] The waveguide intersection 515 has Q-channel waveguides formed on a silicon substrate. These waveguides are formed so as to intersect the light from different lasers of the light source 511 on the substrate. Thereby, for example, when light from the same laser is input to adjacent input ends of the waveguide intersection 515, light from different lasers is output from adjacent output ends of the waveguide intersection 515.

[0039] The second switch group 516 is an optical switch group having Q input terminals and R (= Q × s) output terminals. For example, it includes Q sets of 1×s switches that selectively output the light input from each input terminal to any one of s output destinations. As a result, the Qch of light input from the waveguide intersection 515 is selectively output from Qch of the Rch output terminals. In the embodiment, since the light source 511 is Pch, the light output from the second switch group 516 at the same timing is Pch. Note that s may be either odd or even. Similar to the first switch group 513, the second switch group 516 is configured by combining a plurality of optical switches such as Mach-Zehnder interference type optical switches as will be described later.

[0040] The projection lens 525 is arranged such that the R output terminals of the second switch group 516 are arranged on its focal plane. The projection lens 525 may be configured by, for example, an optical member that acts as a lens in the direction in which at least R output terminals are arranged. The R beams of irradiation light output from the R output terminals are incident on different regions of the projection lens 525, respectively, and are irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0041] <Overall configuration of the branching section of the output light> FIG. 6 is a schematic diagram illustrating the overall configuration of the branching section of the output light extracted from the vertical scanning mechanism 500 illustrated in FIG. 5. In the embodiment, as an example, the number of lasers of the light source 511 is set to P = 8ch. Also, the number of input terminals of the first switch group 513 is set to P = 8ch, and the number of output terminals of the first switch group 513 is set to Q = 64ch. Further, the number of input and output terminals of the waveguide intersection 515 is set to Q = 64ch. And the number of input terminals of the second switch group 516 is set to Q = 64ch, and the number of output terminals of the second switch group 516 is set to R = 512ch. As described above, when the vertical FOV is 25 deg and the vertical angular resolution is set to 0.05 deg, the number of irradiation points required is 500. In the embodiment, as an example, a margin of +12 is provided for 500, and R = 512ch is set. For details of the configuration of each part, further explanation will be given with reference to FIGS. 7 to 9.

[0042] FIG. 7 is a diagram for explaining the light source 511 and the first switch group 513 in the overall configuration diagram of the branching portion of the emitted light illustrated in FIG. 6. The light source 511 is a P = 8ch light source having lasers A, B, C, …, G, H.

[0043] The first switch group 513 is configured by combining a plurality of 1×2 switches that selectively output the input light to either one of the two output terminals in a tree shape. In the embodiment, three layers (seven in number) of 1×2 switches are combined for each of the eight lasers A to H. As a result, the lights (lights a to h) emitted by the lasers A to H respectively are selectively output from one of the eight output terminals of the 8ch output terminals.

[0044] With the above configuration, the first switch group 513 selectively outputs the 8ch light input from the light source 511 from P (= 8) of the Q = 64 (= 8×8) output terminals. Note that the eight 1×2 switches provided at each of the 8ch input terminals of the first switch group 513 are referred to as the first layer SW. The 16 switches provided on the right side (which may also be referred to as the downstream side) of the first layer SW are referred to as the second layer SW. Further, the 32 switches provided on the right side (downstream side) of the second layer SW are referred to as the third layer SW.

[0045] FIG. 8 is a diagram for explaining the waveguide crossing portion 515 in the overall configuration diagram illustrated in FIG. 6. At the 64ch input terminals of the waveguide crossing portion 515, for example, a total of 64 (= 8×8) terminals to which lights a to h respectively emitted from lasers A to H are input in 8ch each are arranged side by side.

[0046] The waveguide intersection 515 has a waveguide of Q = 64ch formed on a silicon substrate. In the embodiment, among the 64ch waveguides, 62ch waveguides excluding one channel each at the top and bottom in FIG. 8 are formed so as to intersect with other waveguides on the substrate. As a result, the order of the light at the input end of the waveguide intersection 515 is different from the order of the light at the output end of the waveguide intersection 515.

[0047] At the 64ch input end of the waveguide intersection 515, the input positions of light a are arranged in the first 8ch counted from the top. In the next 8ch, the input positions of light b are arranged. Similarly, thereafter, the input positions of the light from each laser are arranged in 8ch increments in the order of light c, light d, light e, light f, light g, and light h.

[0048] At the 64ch output end of the waveguide intersection 515, in the first 8ch counted from the top, the output positions of light a, light b, light c, light d, light e, light f, light g, and light h are arranged in order one by one. In the next 8ch as well, the output positions of light a, light b, light c, light d, light e, light f, light g, and light h are arranged in order one by one.

[0049] Similarly, thereafter, the output positions of light a, light b, light c, light d, light e, light f, light g, and light h are arranged in order one by one. With such a configuration, the output positions of the light from each laser are repeated 8 times in the order from light a to light h.

[0050] FIG. 9 is a diagram for explaining the second switch group 516 and the projection lens 525 in the overall configuration diagram illustrated in FIG. 6. The second switch group 516 according to the embodiment substantially constitutes a 1×s (= 8) switch by combining three layers (seven) of 1×2 switches in a tree shape for each of the 64ch input ends. That is, the light input to each of the 64ch input ends is selectively output from one of the corresponding output ends of the 8ch output ends.

[0051] Of the three-layer 1×2 switches provided at each input terminal of 64 channels, the 64 switches provided on the left side (which may also be referred to as the upstream side) of FIG. 9 are called the fourth-layer SW. The 128 switches provided on the right side (which may also be referred to as the downstream side) of the fourth-layer SW are called the fifth-layer SW. Further, the 256 switches provided on the right side (downstream side) of the fifth-layer SW are called the sixth-layer SW.

[0052] With the above configuration, the second switch group 516 having an output terminal of R (=512) channels is configured to selectively output the light input to each input terminal of Q (=64) channels from one of the corresponding eight output terminals. As described above, the R beams of irradiation light output from the R output terminals are incident on different regions of the projection lens 525, respectively, and are irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0053] As is clear from FIG. 9, the lights a, b, c, d, e, f, g, and h are incident on different regions of the projection lens 525, respectively. That is, the lasers A, B, C, D, E, F, G, and H irradiate different irradiation points within the FOV. In other words, the lasers A, B, C, D, E, F, G, and H have different irradiation regions within the FOV.

[0054] As described above, the vertical scanning mechanism 500 switches and controls the laser emitted from the light source 511 and the optical switches of the first switch group 513 and the second switch group 516, thereby switching the incident position (which may also be referred to as a region) on the projection lens 525 where the beam of the irradiation light emitted from the output terminal of the second switch group 516 is incident.

[0055] From the output terminal of the R (= 512) ch of the second switch group 516, R beams of irradiation light corresponding to R irradiation points arranged vertically within the FOV can be emitted. In the embodiment, since the number of lasers that can emit light from the light source 511 at the same timing is 8ch, the number of irradiation light beams that can be emitted simultaneously is 8. The lidar 5 scans the irradiation light vertically by sequentially emitting necessary lasers among the 8ch while shifting the emission timing of the lasers in time series by switching the optical switches of the first switch group 513 and the second switch group 516. As an example, by emitting the 8ch lasers in multiple times as needed, beams of irradiation light can be emitted to the irradiation points arranged vertically within the FOV as illustrated by black circles in FIG. 3. That is, it becomes possible to intelligently change the light emission location according to the required irradiation points.

[0056] As will be described later, the angular resolution in the vertical direction determined by the determination unit 113 corresponds to the interval in the vertical direction of the detection points when acquiring the three-dimensional point cloud data of the next frame. The lidar 5, as an example, refers to the table data (steering information of the irradiation light) showing the relationship between the irradiation points (corresponding to the black circles in FIG. 3) within the FOV stored in the storage unit 12 in advance and the switching states (optical path selection states) of the optical switches of the first switch group 513 and the second switch group 516, and determines the lasers to be emitted and the switching states of the optical switches of the first switch group 513 and the second switch group 516.

[0057] Adopting a solid-state type as the vertical scanning mechanism 52 as in the embodiment can increase the output of the irradiation light in a predetermined range specified within the visual field as the ROI (Region of Interest), extend the detection distance of the predetermined range, or increase the angular resolution of the predetermined range to improve the detection performance for objects and the like, and can enhance the affinity with the processing.

[0058] <Horizontal Scanning Mechanism> In FIG. 4, as an example, the horizontal scanning mechanism 53 controls the beam direction of the irradiation light by reflecting the irradiation light with a polygon mirror rotated by a motor. The horizontal field of view angle required for the lidar 5 as an in-vehicle detector is, for example, 120 deg. Then, it is required to scan the 120 deg range with an angular resolution of 0.1 deg and at a certain predetermined speed. Therefore, in the embodiment, a mechanical scanning mechanism capable of stably scanning a wider deflection angle than the solid-state type is adopted as the horizontal scanning mechanism 53, and the irradiation light is changed in the horizontal direction. As a specific example of the number of irradiation points, when scanning a 120 deg field of view with an angular resolution of 0.1 deg, the irradiation light is irradiated to 1200 irradiation points in the horizontal direction, and the scattered light from each irradiation point is received.

[0059] As described later, the horizontal angular resolution determined by the determination unit 113 corresponds to the horizontal interval of the detection points when acquiring the three-dimensional point cloud data of the next frame. The lidar 5, as an example, refers to table data (steering information of the irradiation light) showing the relationship between the irradiation points (corresponding to the black circles in FIG. 3) within the FOV and the position of the polygon mirror, which is stored in the storage unit 12 in advance, to determine the position of the polygon mirror at the time of laser emission.

[0060] <Configuration of the external recognition device> Details of the external recognition device 50 will be described. As described above with reference to FIG. 2, the external recognition device 50 includes a recognition unit 111, a setting unit 112, a determination unit 113, and a lidar 5. <Recognition unit> The recognition unit 111 generates three-dimensional point cloud data using the time-series detection data detected in the FOV of the lidar 5. In addition, the recognition unit 111 recognizes the road structure in the traveling direction of the road RD on which the host vehicle 101 travels and the detection target on the road RD in the traveling direction based on the detection data measured by the lidar 5. The road structure refers to, for example, a straight road, a curved road, a branching road, an entrance / exit of a tunnel, etc. Furthermore, the recognition unit 111 detects lane lines by performing luminance filtering processing or the like on data indicating, for example, a flat road surface. In this case, the recognition unit 111 may determine that it is a lane line when the height of the road surface where the luminance exceeds a predetermined threshold is substantially the same as the height of the road surface where the luminance does not exceed the predetermined threshold.

[0061] <Recognition of Road Structure> An example of the recognition of the road structure by the recognition unit 111 will be described. The recognition unit 111 recognizes the curb, wall, groove, guardrail, or lane line of the forward road RD in the traveling direction included in the generated point cloud data as the boundary lines RL and RB (FIG. 1A) of the road RD. Further, it recognizes the road structure in the traveling direction indicated by these boundary lines RL and RB. As described above, the lane lines include white lines (including lines of different colors), curb lines, road studs, etc., and the driving lanes of the road RD are defined by the markings by these lane lines. In the embodiment, the boundary lines RL and RB of the road RD defined by the above markings are referred to as lane lines.

[0062] The recognition unit 111 recognizes the area sandwiched between the boundary lines RL and RB as the area corresponding to the road RD. Note that the recognition method for the road RD is not limited to this, and other methods may be used for recognition. In addition, the recognition unit 111 separates the generated point cloud data into point cloud data indicating a flat road surface and point cloud data indicating three-dimensional objects or the like. For example, among the three-dimensional objects on the road in the traveling direction included in the point cloud data, unevenness, steps, undulations, etc. of the road surface where the size exceeds a predetermined value (for example, 15 cm), and objects whose longitudinal and lateral sizes exceed the predetermined value are recognized as detection targets. 15 cm is an example of the size of the detection target and may be changed as appropriate.

[0063] <Setting Unit> The setting unit 112 sets the vertical projection angle φ of the irradiation light for the lidar 5. When the FOV of the lidar 5 is 25 deg in the vertical direction as described above, the vertical projection angle φ is set at intervals of 0.05 deg within the range of 0 to 25 deg. Similarly, the setting unit 112 sets the horizontal projection angle θ of the irradiation light for the lidar 5. When the FOV of the lidar 5 is 120 deg in the horizontal direction as described above, the horizontal projection angle θ is set at intervals of 0.1 deg within the range of 0 to 120 deg. The setting unit 112 sets the irradiation points (corresponding to the black circles in Fig. 3) within the FOV for the lidar 5 based on the angular resolution determined by the determination unit 113 described later. As an example, the intervals in the vertical and horizontal directions of the irradiation points (detection points) within the FOV are made to correspond to the angular resolutions in the vertical and horizontal directions, respectively.

[0064] <Determination unit> The determination unit 113 determines the angular resolution set by the setting unit 112. Here, the angle of the irradiation light with respect to the horizontal direction (for example, the downward angle from the horizontal direction is indicated by a minus sign and the upward angle is indicated by a plus sign) is called the vertical projection angle α (it may also be called the vertical direction angle). First, the determination unit 113 calculates the vertical projection angle α at each depth distance X and the distance DL to the road surface point at each depth distance X, respectively. Specifically, the depth distance X is calculated based on the distance DL from the lidar 5 to the road surface point measured by the lidar 5 and the projection angle α set for the lidar 5 at the time of measurement. The determination unit 113 calculates the relationship between the calculated depth distance X and the vertical direction angle. Also, the determination unit 113 calculates the relationship between the depth distance X and the distance DL. Furthermore, the determination unit 113 calculates the relationship between the depth distance X and the vertical direction angular resolution based on the size of the detection target and the depth distance X. In this way, the vertical direction angular resolution is calculated based on the size of the detection target and the distance DL, and the relationship between the depth distance X and the vertical direction angular resolution is calculated based on the distance DL and the depth distance X.

[0065] Next, the determination unit 113 determines the vertical angular resolution required to recognize the detection target of the above size. For example, in FIG. 3, at the depth distance X where the vertical angular resolution is less than 0.1 deg, 0.05 deg smaller than 0.1 deg is determined as the required angular resolution. Also, at the depth distance X where the vertical angular resolution is 0.1 deg or more and less than 0.2 deg, 0.1 deg smaller than 0.2 deg is determined as the required angular resolution. Similarly, for the depth distance X where the vertical angular resolution is 0.2 deg or more and less than 0.3 deg, and the depth distance X where the vertical angular resolution is 0.3 deg or more and less than 0.4 deg, 0.2 deg and 0.3 deg, which are smaller respectively, are determined as the required angular resolutions.

[0066] The determined required vertical angular resolution can be reflected as the vertical interval of the detection points when acquiring the three-dimensional point cloud data of the next frame. Also, the determination unit 113 may determine the required horizontal angular resolution for recognizing the detection target according to the size of the detection target and the depth distance X. The required horizontal angular resolution can also be reflected as the horizontal interval of the detection points when acquiring the three-dimensional point cloud data of the next frame. Note that the required horizontal angular resolution may be made to coincide with the previously determined required vertical angular resolution. In other words, on the same horizontal line as the detection point where the required vertical angular resolution is determined to be 0.05 deg, the required horizontal angular resolution is determined to be 0.05 deg. Similarly, on the same horizontal line as the detection point where the required vertical angular resolution is determined to be 0.1 deg, the required horizontal angular resolution is determined to be 0.1 deg. Further, for other required angular resolutions, on the same horizontal line as the detection point where the required vertical angular resolution is determined, the required horizontal angular resolution is determined to have the same value as the required vertical angular resolution.

[0067] <Generation of Position Data> The external recognition device 50 can generate continuous position data by mapping data indicating the position of a detection target detected based on the time-series point cloud data measured in real time by the lidar 5 onto, for example, a two-dimensional map in the x-y plane. In the x-y space, information indicating the height Z is omitted, and information on the depth distance X and the horizontal distance Y remains. The recognition unit 111 acquires the position information of a three-dimensional object or the like on the two-dimensional map stored in the storage unit 12, and calculates the relative position of the three-dimensional object or the like from the moving speed and moving direction (for example, azimuth angle) of the host vehicle 101 by performing coordinate conversion centered on the position of the host vehicle 101. Every time point cloud data is acquired by the lidar 5 through measurement, the recognition unit 111 performs coordinate conversion on the relative position of a three-dimensional object or the like based on the acquired point cloud data centered on the position of the host vehicle 101 and records it on the two-dimensional map.

[0068] <Description of the flowchart> FIG. 10 is a flowchart showing an example of the processing executed by the arithmetic unit 11 of the controller 10 in FIG. 2 according to a predetermined program. The processing shown in the flowchart of FIG. 10 is repeated at a predetermined cycle, for example, while the host vehicle 101 is traveling in the automatic driving mode.

[0069] First, in step S10, the arithmetic unit 11 causes the lidar 5 to acquire three-dimensional point cloud data and proceeds to step S20. In step S20, the arithmetic unit 11 calculates the road surface gradient and the maximum depth distance in the traveling direction of the road RD based on the point cloud data acquired by the lidar 5.

[0070] For example, the arithmetic unit 11 obtains point cloud data indicating a flat road surface by detecting and separating data of a three-dimensional object or the like on the road RD from the point cloud data of the detection points determined by the determination unit 113. The three-dimensional object or the like includes obstacles on the road, curbs provided at the left and right ends of the road RD, walls, ditches, guardrails, etc., and other vehicles such as motorcycles traveling on the road. Next, the arithmetic unit 11 calculates the road surface gradient of the road RD based on the point cloud data indicating the road surface. Since the calculation process of the road surface gradient is well-known, detailed description thereof will be omitted. Further, the arithmetic unit 11 calculates the maximum depth distance and proceeds to step S30. The maximum depth distance may be the farthest depth distance detectable by the lidar 5.

[0071] In step S30, the arithmetic unit 11 calculates the vertical projection angle α and the distance DL to the road surface point at each depth distance X, and proceeds to step S40. The relationship between the projection angle α and the depth distance X may be stored in the storage unit 12 in advance.

[0072] In step S40, the arithmetic unit 11 calculates the required angular resolution at each depth distance X and proceeds to step S50. The required angular resolution is the angular resolution required to detect a detection target of a specified size in advance. The relationship between the depth distance X and the angular resolution may be stored in the storage unit 12 in advance.

[0073] In step S50, the arithmetic unit 11 determines, by the determination unit 113, the vertical angular resolution to the required angular resolution and proceeds to step S60. The vertical required angular resolution determined here is reflected as the vertical interval of the detection points when acquiring the three-dimensional point cloud data of the next frame.

[0074] In step S60, the determination unit 113 of the arithmetic unit 11 determines the horizontal angular resolution to the required angular resolution and proceeds to step S70. The horizontal required angular resolution determined here is reflected as the horizontal interval of the detection points when acquiring the three-dimensional point cloud data of the next frame.

[0075] In step S70, the arithmetic unit 11 determines the coordinates of the detection points. More specifically, the coordinates indicating the positions of the detection points illustrated by the black circles in FIG. 3 are determined. The control unit 54 reflects the position of the detection points determined in step S70 as the steering information of the irradiation light by the lidar 5 when acquiring the three-dimensional point cloud data of the next frame. Further, the recognition unit 111 recognizes a three-dimensional object or the like in the traveling direction of the road RD on which the host vehicle 101 travels based on the detection data detected at the position of the detection point determined in step S70.

[0076] Note that each time the point cloud data is acquired in step S10, the calculation unit 11 generates continuous position data in two dimensions by mapping the relative positions of three-dimensional objects or the like based on the point cloud data onto a two-dimensional map in the x-y plane. Then, the relative positions of three-dimensional objects or the like based on the point cloud data can be coordinate-transformed with the position of the host vehicle 101 as the center and recorded on the two-dimensional map.

[0077] In step S80, the calculation unit 11 determines whether to end the process. When the host vehicle 101 is continuing to travel in the automatic driving mode, the calculation unit 11 makes a negative determination in step S80 and returns to step S10 to repeat the above-described process. By returning to step S10, the measurement of three-dimensional objects or the like based on the point cloud data is periodically repeated during the travel of the host vehicle 101. On the other hand, when the host vehicle 101 has ended the travel in the automatic driving mode, the calculation unit 11 makes an affirmative determination in step S80 and ends the process according to FIG. 10.

[0078] According to the embodiment described above, the following operational effects are obtained. (1) The vertical scanning mechanism 500 as the optical signal switching module used in the lidar 5 inputs optical signals (light a to light h) from lasers A to H as a plurality of light sources, and a first switch group 513 as an optical branching unit that selectively switches the output destination of each optical signal to one of a plurality of eight-channel output destinations, a waveguide crossing unit 515 as a waveguide type crossing unit that crosses at least some of the plurality of optical signals (light a to light h) output from the first switch group 513, and output terminals 1 to Q (= 64) that individually output the plurality of optical signals (light a to light h) output from the waveguide crossing unit 515. In particular, by providing the waveguide crossing section 515 that crosses a plurality of optical signals (light a, light b, etc.) output from the first switch group 513, the vertical scanning mechanism 500 can output the optical signals (light a, light b, etc.) after crossing by the waveguide crossing section 515. As a result, compared with the case where the waveguide crossing section 515 is not provided, it becomes possible to densify the optical signals (light a, light b, etc.) output from the vertical scanning mechanism 500. More specifically, by changing the order of the optical signals output from the output end of the vertical scanning mechanism 500, for example, the output end of light a and the output end of light b can be brought closer to each other, or the positional relationship between the output ends of light a and light b can be interchanged. If a multilayer optical switch such as an integrated optical switch is combined with the conventional technology (a configuration that only stacks a plurality of wavelength division elements), although the optical signals output from the output end of the integrated optical switch can be densified, the size of the integrated optical switch that is too large hinders the miniaturization of the lidar. Furthermore, since the power of the irradiation light decreases due to the internal loss of the integrated optical switch, it becomes difficult to meet the needs as an in-vehicle detector (particularly, miniaturization, long-distance measurement, etc.). However, according to the vertical scanning mechanism 500 according to the embodiment that is not affected by the size and internal loss of the integrated optical switch, it becomes possible to realize miniaturization, long-distance measurement, etc. as an in-vehicle detector.

[0079] (2) In the vertical scanning mechanism 500 described in (1) above, focusing on laser A and laser B, the first switch group 513 inputs an optical signal (light a) from laser A as the first light source, and selectively outputs the optical signal (light a) from one of the output destinations of eight channels as the first predetermined number (for example, among the switches of the first to third layers constituting the first switch group 513, a three-layer 1×2 switch that switches the optical path of light a), and inputs an optical signal (light b) from laser B as the second light source, and selectively outputs the optical signal (light b) from one of the output destinations of eight channels as the second predetermined number (for example, among the switches of the first to third layers constituting the first switch group 513, a three-layer 1×2 switch that switches the optical path of light b). The waveguide crossing section 515 crosses at least a part of the optical signals of the optical signal (light a) output from the first optical switch and the optical signal (light b) output from the second optical switch, and the output end includes (the first predetermined number + the second predetermined number = 16) channels. With this configuration, the configurations (number of channels) of the switches constituting the optical path of light a and the optical path of light b are substantially equal, and it becomes possible to suppress the bias of loss between the optical paths.

[0080] (3) In the vertical scanning mechanism 500 described in (2) above, among the output ends of (8 + 8) channels, there are at least a plurality of sets (sets of light a and light b) each composed of an output end from which an optical signal (light a) from laser A is output and an output end from which an optical signal (light b) from laser B is output. With this configuration, it becomes possible to perform light projection to the irradiation points within the FOV of the lidar 5 using a plurality of lasers A and lasers B, and to project light from lasers A and B to at least a plurality of irradiation points respectively. As a result, compared with the case where a plurality of lasers each project light to only one irradiation point, the number of lasers to be provided in the lidar 5 can be suppressed.

[0081] (4) In the vertical scanning mechanism 500 of (2) or (3) above, an optical signal (optical a) output from the first optical switch among the optical signals output from the waveguide intersection 515 is input, and a first predetermined number (8) of third optical switches (for example, three layers of 1×2 switches that switch the optical path of optical a among the switches of the fourth to sixth layers constituting the second switch group 516) that selectively output an optical signal from one of the output destinations of the third predetermined number (8) of channels, and an optical signal (optical b) output from the first optical switch among the optical signals output from the waveguide intersection 515 is input, and a second predetermined number (8) of fourth optical switches (for example, three layers of 1×2 switches that switch the optical path of optical b among the switches of the fourth to sixth layers constituting the second switch group 516) that selectively output an optical signal from one of the output destinations of the third predetermined number (8) of channels are further provided. By providing the third and fourth optical switches on the downstream side of the waveguide intersection 515 in this way, it becomes possible to increase the number of output ends of the optical signal without increasing the number of intersections. Also, compared with the case where the third optical switch is provided on the upstream side of the waveguide intersection 515, it becomes possible to suppress the number of intersections of the waveguides of the waveguide intersection 515 to a small number. That is, rather than intersecting the optical signals of the number of output ends of the third optical switch ((the first predetermined number + the second predetermined number) × the third predetermined number), intersecting the optical signals of (the first predetermined number + the second predetermined number) can suppress the number of intersections to a small number, so it becomes possible to reduce the area of the chip constituting the configuration of the waveguide intersection 515, simplify the chip design, and reduce crosstalk and reflection.

[0082] (5) In the vertical scanning mechanism 500 of (4) above, the first optical switch, the second optical switch, the third optical switch, and the fourth optical switch are each configured by combining a plurality of stages of 1×2 optical switches. With this configuration, the vertical scanning mechanism 500 can be realized with a simple configuration.

[0083] (6) In the vertical scanning mechanism 500 of the above (5), the signal light of (the first predetermined number + the second predetermined number) × the third predetermined number of channels selectively output from the first predetermined number of third optical switches and the second predetermined number of fourth optical switches is incident on different regions of a projection lens 525 as a projection optical system, respectively. With this configuration, it becomes possible to project the signal light of (the first predetermined number + the second predetermined number) × the third predetermined number of channels selectively output from the third optical switch to different irradiation points within the FOV.

[0084] The above embodiment can be modified in various forms. Hereinafter, modification examples will be described. (Modification Example 1) In the above-described embodiment, an example in which a solid-state scanning mechanism is adopted only for the vertical scanning mechanism 500, which is one of the first scanning unit and the second scanning unit, has been described. Instead, a solid-state scanning mechanism may be adopted for the horizontal scanning mechanism 53 as the second scanning unit in the same manner as in the case of the vertical scanning mechanism 500. Further, a solid-state scanning mechanism may be adopted only for the horizontal scanning mechanism 53, which is one of the first scanning unit and the second scanning unit.

[0085] When a solid-state scanning mechanism is adopted only for one of the first scanning unit and the second scanning unit, it is preferably adopted as the vertical scanning mechanism 500 for the following reasons. That is, the vertical viewing angle (25 deg in the above example) required for the lidar 5 as an in-vehicle detector is narrower than the horizontal viewing angle (120 deg in the above example), and the range where an angular resolution finer than 0.1 deg, i.e., 0.05 deg, is required within the viewing angle of 25 deg is even narrower (for example, about 10 deg). Therefore, when irradiating high-angular-resolution irradiation light only to 10 deg within the viewing angle of 25 deg, it is possible to make the number of vertical irradiation points (corresponding to the number R of output ends of the second switch group 516) less than 512 described above.

[0086] Also, while the irradiation light is driven and controlled in the horizontal direction by the horizontal scanning mechanism 53, the scanning drive of the vertical scanning mechanism 500 can be stopped. Therefore, one of the reasons is that the vertical scanning speed may be slower than the horizontal scanning speed. From the above, when adopting a solid-state scanning mechanism only in one of the first scanning unit and the second scanning unit, the solid-state scanning mechanism, which is superior in durability against vibration and impact compared to the mechanical type, is used as the vertical scanning mechanism 500.

[0087] (Modification Example 2) The number of irradiation points within the FOV of the above-described lidar 5 (512 in the vertical direction and 1200 in the horizontal direction), the number P of lasers constituting the light source (= 8), the number of optical switches constituting the first switch group 513 (8 + 16 + 32 = 56), the number Q of output terminals of the first switch group 513 (= 64), the number of optical switches constituting the second switch group 516 (7×64 = 448), and the number R of output terminals of the second switch group 516 (= 512) are all examples and can be changed as appropriate. Another example will be described in the following Modification Example 3.

[0088] (Modification Example 3) In the above-described embodiment, the case where the number of channels of the output terminal of the first optical switch (= the first predetermined number), the number of channels of the output terminal of the second optical switch (= the second predetermined number), the number of channels of the output terminals of the third and fourth optical switches (= the third predetermined number), the number of the third optical switches (= the first predetermined number), and the number of the fourth optical switches (= the second predetermined number) are the same (= 8) has been described. In Modification Example 3, the case where the first predetermined number, the second predetermined number, and the third predetermined number are not equal will be described. As an example, the case where the first predetermined number (for example, 6) and the second predetermined number (for example, 5) are different, and the third predetermined number (for example, 8) is larger than the first predetermined number and the second predetermined number will be described. In Modification 3, the number of irradiation points within the FOV of the lidar 5 (vertical direction 504, horizontal direction 1200), the number P of lasers constituting the light source (= 12), the number of optical switches constituting the first switch group 513 (12 + 24 + 15 = 51), the number Q of output terminals of the first switch group 513 (= 63), the number of optical switches constituting the second switch group 516 (7 × 63 = 441), and the number R of output terminals of the second switch group 516 (= 504).

[0089] <Overall Configuration of Light Output Branch Section> The configuration of Modification 3 will be described with reference to the schematic diagram of FIG. 6. The number of lasers of the light source 511 is set to P = 12 channels. Also, the number of input terminals of the first switch group 513 is set to P = 12 channels, and the number of output terminals of the first switch group 513 is set to Q = 63 channels. Further, the number of input and output terminals of the waveguide intersection section 515 is set to Q = 63 channels. Then, the number of input terminals of the second switch group 516 is set to Q = 63 channels, and the number of output terminals of the second switch group 516 is set to R = 504 channels. As described above, when the FOV in the vertical direction is 25 deg and the angular resolution in the vertical direction is set to 0.05 deg, the required number of irradiation points is 500. In Modification 3, a margin of +4 is added to 500, and R = 504 channels is set. The details of the configuration of each part will be further described with reference to FIGS. 11 to 13.

[0090] FIG. 11 is a diagram for explaining the light source 511 and the first switch group 513 in the overall configuration diagram of the light output branch section illustrated in FIG. 6. The light source 511 is a light source with P = 12 channels having lasers A, B, C, …, K, L.

[0091] The first switch group 513 is configured by combining a plurality of 1×2 switches in a tree shape, which selectively outputs the input light to one of the two output terminals. In Modification 3, five 1×2 switches are combined for each of the three lasers A, B, and L. As a result, the lights (light a, light b, and light l) emitted by lasers A, B, and L respectively are selectively output from one of the six output terminals.

[0092] Also, four 1×2 switches are combined for each of the nine lasers C, D, …, K. As a result, the lights (light c, light d, …, and light k) emitted by lasers C, D, …, and K respectively are selectively output from one of the five output terminals.

[0093] With the above configuration, the first switch group 513 selectively outputs the 12-channel light input from the light source 511 from P (=12) of the Q (=63 = 3×6 + 9×5) output terminals. Note that the twelve 1×2 switches provided at each of the 12 input terminals of the first switch group 513 are referred to as the first-layer SW. The twenty-four switches provided on the right side (which may also be referred to as the downstream side) of the first-layer SW are referred to as the second-layer SW. Also, the fifteen switches provided on the right side (downstream side) of the second-layer SW are referred to as the third-layer SW.

[0094] FIG. 12 is a diagram for explaining the waveguide intersection 515 in the overall configuration diagram illustrated in FIG. 6. At the 63 input terminals of the waveguide intersection 515, for example, there are arranged a total of 63 (=6 + 6 + 9×5 + 6) terminals, including 6 portions of light a emitted by laser A, 6 portions of light b emitted by laser B, 5 portions of light c to light k emitted by lasers C to K respectively, and 6 portions of light l emitted by laser L.

[0095] The waveguide intersection 515 has a waveguide of Q = 63ch formed on a silicon substrate. In Modification 3, among the 63ch waveguides, 61ch waveguides excluding 1ch each at the top and bottom in FIG. 12 are formed so as to intersect with other waveguides on the substrate. As a result, the order of light at the input end of the waveguide intersection 515 is different from the order of light at the output end of the waveguide intersection 515.

[0096] At the 63ch output end of the waveguide intersection 515, for example, for the first 6ch, light a, light b, light c, light d, light e, and light f for 1ch are arranged. For the next 8ch, light a, light b, light g, light h, light i, light j, light k, and light l for 1ch are arranged. For the next 12ch, light a, light b, light c, light d, light e, light f, light g, light h, light i, light j, light k, and light l for 1ch are arranged.

[0097] For the next 12ch, light a, light b, light c, light d, light e, light f, light g, light h, light i, light j, light k, and light l for 1ch are arranged. For the next 12ch, light a, light b, light c, light d, light e, light f, light g, light h, light i, light j, light k, and light l for 1ch are arranged.

[0098] For the next 7ch, light a, light b, light c, light d, light e, light f, and light l for 1ch are arranged. For the last 6ch, light g, light h, light i, light j, light k, and light l for 1ch are arranged.

[0099] FIG. 13 is a diagram for explaining the second switch group 516 and the projection lens 525 in the overall configuration diagram illustrated in FIG. 6. The second switch group 516 according to Modification 3 substantially constitutes a 1×s (= 8) switch by combining three layers (seven) of 1×2 switches in a tree shape for each of the 63ch input ends. That is, the light input to each of the 63ch input ends is selectively output from one of the corresponding eight output ends.

[0100] Of the three-layer 1×2 switches provided at each input terminal of 63 channels, the 63 switches provided on the left side (which may also be referred to as the upstream side) of FIG. 13 are called the fourth-layer SW. The 126 switches provided on the right side (which may also be referred to as the downstream side) of the fourth-layer SW are called the fifth-layer SW. Also, the 252 switches provided on the right side (downstream side) of the fifth-layer SW are called the sixth-layer SW.

[0101] With the above configuration, the second switch group 516 having an output terminal of R (=504) channels is configured to selectively output the light input to each input terminal of Q (=63) channels from one of the corresponding eight output terminals. As described above, the R beams of irradiation light output from the R output terminals are respectively incident on different regions of the projection lens 525. Then, they are irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0102] As is clear from FIG. 13, light a, light b, light c, light d, light e, light f, light g, light h, light i, light j, light k, and light l are respectively incident on different regions of the projection lens 525. That is, laser A, laser B, laser C, laser D, laser E, laser F, laser G, laser H, laser I, laser J, laser K, and laser L irradiate different irradiation points within the FOV. In other words, laser A, laser B, laser C, laser D, laser E, laser F, laser G, laser H, laser I, laser J, laser K, and laser L have different irradiation regions within the FOV.

[0103] As described above, the vertical scanning mechanism 500 switches and controls the laser emitted from the light source 511 and the optical switches of the first switch group 513 and the second switch group 516, thereby switching the incident position (which may also be referred to as a region) on the projection lens 525 where the beam of the irradiation light emitted from the output terminal of the second switch group 516 is incident.

[0104] From the output terminal of the R(=504)ch of the second switch group 516, R beams of irradiation light corresponding to R irradiation points arranged vertically within the FOV can be emitted. In Modification 3, since the number of lasers that can emit light at the same timing from the light source 511 is 12ch, the number of irradiation light beams that can be emitted simultaneously is 12. The lidar 5 scans the irradiation light vertically by sequentially emitting the necessary lasers out of the 12ch while shifting the light emission timing of the lasers in time series by switching the optical switches of the first switch group 513 and the second switch group 516. As an example, when the 12ch lasers are emitted in 42 divisions, 504 beams of irradiation light arranged vertically within the FOV can be emitted.

[0105] According to Modification 3 described above, the following operational effects can be obtained. The lidar 5 includes a vertical scanning mechanism 500 as a first scanning unit that scans and irradiates an optical signal (lights a to l) in the vertical direction as a first direction, and a horizontal scanning mechanism 53 as a second scanning unit that scans and irradiates the optical signal (lights a to l) in the horizontal direction as a second direction intersecting the vertical direction, and functions as an in-vehicle detector that scans and irradiates the optical signal (lights a to l) within the FOV to detect the external situation. Focusing on the optical signals from laser B and laser C among lasers A to L, the vertical scanning mechanism 500 as at least one of the first scanning unit and the second scanning unit inputs an optical signal (light b) from laser B as the first light source, and a first optical switch (a general term for the first to third layer SWs that switch the optical path of light b among the first switch group 513) that selectively outputs the optical signal (light b) from one of the output ends of m1 channels (for example, 6), inputs an optical signal (light c) from laser C as the second light source, and a second optical switch (a general term for the layer to third layer SWs that switch the optical path of light c among the first switch group 513) that selectively outputs the optical signal (light c) from one of the output ends of m2 channels (for example, 5), inputs the optical signal (light b) output from the first optical switch, and m1 third optical switches (a general term for the fourth to sixth layer SWs that switch the optical path of light b among the second switch group 516) that selectively output the optical signal (light b) from one of the output ends of s channels (for example, 8), inputs the optical signal (light c) output from the second optical switch, and m2 fourth optical switches (a general term for the fourth to sixth layer SWs that switch the optical path of light c among the second switch group 516) that selectively output the optical signal (light c) from one of the output ends of s channels (for example, 8), and a waveguide intersection 515 as a waveguide type intersection that intersects at least some of the optical signals of the optical signal (light b) output from the first optical switch and the optical signal (light c) output from the second optical switch. In particular, by providing the waveguide intersection 515 that intersects the optical signals (light b, light c), the vertical scanning mechanism 500 can output the optical signal (light b or light c) after intersection by the waveguide intersection 515. As a result, compared with the case where the waveguide intersection 515 is not provided, it becomes possible to densify the optical signals (light b and light c) output from the vertical scanning mechanism 500. More specifically, by changing the order of the optical signals output from the output end of the vertical scanning mechanism 500, for example, it becomes possible to bring the output end of light b and the output end of light c closer to each other, or to change the positional relationship between the output ends of light b and light c. If a multilayer optical switch such as an integrated optical switch is combined with the conventional technology (a configuration that only stacks a plurality of wavelength division elements), even if the optical signals output from the output end of the integrated optical switch can be made dense, the overly large size of the integrated optical switch will hinder the miniaturization of the lidar. Furthermore, since the power of the irradiation light decreases due to the internal loss of the integrated optical switch, it becomes difficult to meet the needs as an in-vehicle detector (especially, miniaturization, long-distance measurement, etc.). However, according to the lidar 5 according to an embodiment that is not affected by the size and internal loss of the integrated optical switch, it becomes possible to realize miniaturization, long-distance measurement, etc. as an in-vehicle detector.

[0106] The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications.

Explanation of Reference Numerals

[0107] 3 Internal sensor group, 4 Camera, 5 Lidar, 10 Controller, 11 Arithmetic unit, 12 Storage unit, 50 External recognition device, 52,500 Vertical scanning mechanism, 53 Horizontal scanning mechanism, 54 Control unit, 100 Vehicle control device, 101 Own vehicle, 111 Recognition unit, 112 Setting unit, 113 Decision unit, 114 Travel control unit, 511 Light source, 512 BPD, 513 First switch group, 515 Waveguide intersection, 516 Second switch group, 525 Projection lens, AC Actuator

Claims

1. An optical signal switching module for a rider, comprising: an optical branching unit that inputs optical signals from a plurality of light sources and selectively switches the output destination of each optical signal to one of the output destinations of a plurality of channels; a waveguide type crossing unit that crosses at least some of the plurality of optical signals output from the optical branching unit; a plurality of channel output ends that individually output the plurality of optical signals output from the crossing unit; An optical signal switching module characterized by comprising.

2. In the optical signal switching module according to Claim 1, the optical branching unit includes: a first optical switch that inputs an optical signal from a first light source and selectively outputs the optical signal from one of the output destinations of a first predetermined number of channels; a second optical switch that inputs an optical signal from a second light source and selectively outputs the optical signal from one of the output destinations of a second predetermined number of channels, the crossing unit crosses at least some of the optical signals output from the first optical switch and the optical signals output from the second optical switch, the output end includes (the first predetermined number + the second predetermined number) channels, An optical signal switching module characterized by this.

3. In the optical signal switching module according to Claim 2, among the output ends of the (the first predetermined number + the second predetermined number) channels, a plurality of sets composed of an output end where an optical signal from the first light source is output and an output end where an optical signal from the second light source is output are included, An optical signal switching module characterized by this.

4. In the optical signal switching module according to Claim 2 or 3, a first predetermined number of third optical switches that input the optical signals output from the first optical switch among the optical signals output from the crossing unit and selectively output the optical signals from one of the output destinations of a third predetermined number of channels; a second predetermined number of fourth optical switches that input the optical signals output from the second optical switch among the optical signals output from the crossing unit and selectively output the optical signals from one of the output destinations of the third predetermined number of channels; further comprising An optical signal switching module characterized by this.

5. In the optical signal switching module according to Claim 4, The first optical switch, the second optical switch, the third optical switch, and the fourth optical switch are each configured by combining a plurality of stages of 1×2 optical switches. An optical signal switching module characterized by this. **Claim 6** In the optical signal switching module according to claim 5, The signal light of the channels of ((the first predetermined number + the second predetermined number) × the third predetermined number) selectively output from the first predetermined number of the third optical switches and the second predetermined number of the fourth optical switches is incident on different regions of the projection optical system, respectively. An optical signal switching module characterized by this.

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