Optical signal switching module

Abstract

An optical signal switching module (500) for a lidar (5) is provided with: an optical branching unit (513) into which optical signals from a plurality of light sources are input, and which selectively switches the output destination of each optical signal to one of the output destinations of a plurality of channels; a waveguide-type intersection section (515) that intersects at least some of the plurality of optical signals output from the optical branching section (513); and output terminals of a plurality of channels that individually output the plurality of optical signals output from the intersection section (515).

Description

Technical Field

[0001] The present invention relates to an optical signal switching module for a laser radar for detecting an object, measuring the distance to the object, etc. Background Art

[0002] LiDAR (Light Detection And Ranging) is a key device that supports autonomous driving technology. LiDAR changes the irradiation angle of irradiated laser light in two axial directions to perform scanning, detects objects based on position information of each detection point, and measures the distance to the object.

[0003] For example, Patent Document 1 discloses a laser radar system that operates a wave splitting element such as an optical phased array (OPA) to irradiate laser light to different sample areas within a field of view.

[0004] Generally, when a laser radar is installed in a car or the like, it is necessary to irradiate laser light to hundreds or more irradiation points on each axis. When conventional technology is used, a splitter element that selectively outputs laser light from one of the output ends of two channels is stacked and hundreds or more output ends are switched one by one, so it is difficult to densely output laser light from multiple output ends in the final stage.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-517857 (JP 2022-517857 A). Summary of the invention

[0008] An optical signal switching module of one technical solution of the present invention is an optical signal switching module for a laser radar, comprising: an optical branching section, which respectively inputs optical signals from multiple light sources and selectively switches the output destination of each optical signal to one of the output destinations of multiple channels; a waveguide-type intersection section, which crosses at least a part of the multiple optical signals output from the optical branching section; and output ends of multiple channels, which individually output the multiple optical signals output from the intersection section. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The objects, features and advantages of the present invention will be further clarified through the following description of the embodiments in conjunction with the accompanying drawings.

[0010] Figure 1A It is a diagram showing a state where a vehicle is traveling on a road.

[0011] Figure 1B This is a schematic diagram showing an example of detection data of a laser radar.

[0012] Figure 2 It is a block diagram showing the main part structure of the vehicle control device.

[0013] Figure 3 It is a schematic diagram illustrating the irradiation point of the laser radar.

[0014] Figure 4 It is a schematic diagram showing the structure of a laser radar according to an exemplary embodiment.

[0015] Figure 5 This is an example Figure 4 A block diagram of the main structure of a vertical direction scanning mechanism in which a transceiver and a vertical direction scanning mechanism are integrated.

[0016] Figure 6 It is an example from Figure 5 Schematic diagram of the overall structure of the branching unit for extracting output light.

[0017] Figure 7 Yes Description Figure 6 Figure 4 shows a diagram of a light source and a first switch group.

[0018] Figure 8 Yes Description Figure 6 Figure 2. Waveguide intersection in Fig.

[0019] Fig. 9 Yes Description Figure 6 Figure 2 shows a diagram of the second switch group in FIG.

[0020] Fig.10 It is shown by Figure 2 A flowchart of an example of a process executed by the CPU of the controller.

[0021] Fig.11 It is a diagram for explaining the light source and the first switch group in Modification Example 3.

[0022] Fig.12 This is a diagram for explaining the waveguide intersection portion in Modification Example 3.

[0023] Fig.13 This is a diagram for explaining the second switch group in Modification Example 3. DETAILED DESCRIPTION

[0024] Embodiments of the invention will be described below with reference to the drawings.

[0025] First, an outside world recognition device using a laser radar device (hereinafter referred to as a laser radar) as a vehicle-mounted detector as an embodiment of the invention and a vehicle equipped with the outside world recognition device are described.

[0026] The external recognition device can be mounted on a vehicle with an automatic driving function, that is, an automatic driving vehicle. It should be noted that, in the implementation mode, sometimes the vehicle equipped with the external recognition device is referred to as the present vehicle, as distinguished from other vehicles. The present vehicle can be any of an engine vehicle having an internal combustion engine (engine) as a driving source, an electric vehicle having a driving motor as a driving source, and a hybrid vehicle having an engine and a driving motor as driving sources. The present vehicle can not only travel in an automatic driving mode that does not require the driver's driving operation, but also in a manual driving mode in which the driver performs driving operations.

[0027] When an autonomous vehicle is driving in an autonomous driving mode (hereinafter referred to as automatic driving or autonomous driving), it recognizes the external conditions around the vehicle based on the detection data of on-board sensors such as laser radar and cameras. Based on the recognition results, the autonomous vehicle generates a driving trajectory (target trajectory) that passes a specified time from the current moment, and controls the driving actuator to make the vehicle drive along the target trajectory.

[0028] Figure 1A 1 is a diagram showing a state where the host vehicle 101 as an automatically driven vehicle is traveling on a road RD. Figure 1B 1 is a schematic diagram showing an example of detection data obtained by a laser radar mounted on the vehicle 101 and directed in the direction of travel of the vehicle 101. The measurement point (also referred to as the detection point) of the laser radar is the point information where the irradiated laser is reflected (scattered) back at a certain point on the surface of an object. The point information includes the distance from the laser light source to the point, the intensity of the reflected (scattered) laser light, and the relative speed between the laser light source and the point.

[0029] Will be Figure 1B The data composed of the multiple detection points shown is called point cloud data. Figure 1B Based on Figure 1A The point cloud data of the detection points on the surface of the object in the field of view (FOV) of the laser radar. For example, the FOV can be 120 degrees in the horizontal direction (also called the road width direction) of the vehicle 101 and 25 degrees in the vertical direction (also called the up and down direction). The value of FOV can be appropriately changed according to the specifications of the external recognition device. The vehicle 101 is based on Figure 1B The point cloud data shown recognizes the external conditions around the vehicle, more specifically, the road structure and objects around the vehicle, and generates a target trajectory based on the recognition result.

[0030] However, as a method of fully identifying the external conditions around the vehicle, it is possible to consider increasing the number of irradiation points of electromagnetic waves irradiated from vehicle-mounted detectors such as laser radar (in other words, increasing the density of irradiation points of electromagnetic waves to increase the number of detection points constituting point cloud data). On the other hand, when the number of irradiation points of electromagnetic waves is increased (the number of detection points is increased), it is possible that the processing load for controlling the vehicle-mounted detector increases, the capacity of the detection data (point cloud data) obtained by the vehicle-mounted detector increases, and the processing load for the point cloud data increases. In particular, when there are many objects on the road or beside the road, the capacity of the point cloud data increases further.

[0031] Therefore, in consideration of the above-mentioned points, the following outside world recognition device is constructed in the embodiment.

[0032] <Outline>

[0033] The external recognition device equipped with the laser radar of the embodiment intermittently irradiates irradiation light as an example of electromagnetic waves from the laser radar of the host vehicle 101 traveling on the road RD to the traveling direction of the host vehicle 101, and discretely obtains point cloud data at different positions on the road RD. The irradiation range of the irradiation light irradiated from the laser radar is set by the point cloud data of the previous frame obtained by the laser radar through the previous irradiation and the point cloud data of the next frame obtained by the laser radar through the current irradiation, so as to avoid a blank interval of data in the traveling direction of the road RD.

[0034] The detection point density within the irradiation range is set higher for a road surface far from the vehicle 101, and lower for a road surface close to the vehicle 101, so that the total number of detection points used for recognition processing is suppressed compared to the case where a high detection point density is set for all road surfaces within the irradiation range. Therefore, there is no need to reduce the recognition accuracy of the position (distance from the vehicle 101) and size of the object or the like recognized based on the point cloud data, and the number of detection points used for recognition processing can be reduced.

[0035] Such an outside world recognition device will be described in further detail.

[0036] <Structure of vehicle control device>

[0037] Figure 2 1 is a block diagram showing the main structure of a vehicle control device 100 including an external recognition device. The 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 laser radar 5, and an actuator AC for driving. In addition, the vehicle control device 100 includes an external recognition device 50 constituting a part of the vehicle control device 100. The external recognition device 50 recognizes the external conditions around the vehicle based on the detection data of the vehicle-mounted detectors such as the camera 4 and the laser radar 5.

[0038] The communication unit 1 communicates with various servers not shown in the figure through a network including a wireless communication network represented by the Internet, a mobile phone network, etc., and obtains map information, driving history information, traffic information, etc. from the server regularly or at any time. The network includes not only a public wireless communication network, but also a closed communication network set up in each specified 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 sent from a positioning satellite. The positioning satellite is an artificial satellite such as a GPS satellite and a quasi-zenith satellite. The positioning unit 2 uses the positioning information received by the positioning sensor to determine the current position (latitude, longitude, altitude) of the vehicle 101.

[0039] 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, an acceleration sensor that detects 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 source, and a yaw rate sensor that detects the angular velocity of the center of gravity of the host vehicle 101 around the vertical axis. Sensors that detect the driving operation of the driver in the manual driving mode, such as the operation of the accelerator pedal, the operation of the brake pedal, and the operation of the steering wheel, are also included in the internal sensor group 3.

[0040] The camera 4 has a CCD (charge coupled device), a CMOS (complementary metal oxide semiconductor) or other imaging element, and images the surroundings (front, rear, and sides) of the vehicle 101. The laser radar 5 receives scattered light relative to the irradiated light to detect the distance from the vehicle 101 to the surrounding objects, the position and shape of the objects, etc.

[0041] The actuator AC is a driving actuator for controlling the driving of the vehicle 101. When the driving source is an engine, the actuator AC includes a throttle actuator for adjusting the opening of the throttle valve of the engine (throttle opening). When the driving source is a driving motor, the driving motor is included in the actuator AC. The brake actuator for operating the brake device of the vehicle 101 and the steering actuator for driving the steering device are also included in the actuator AC.

[0042] The controller 10 includes an electronic control unit (ECU). More specifically, the controller 10 includes a computer having a computing unit 11 such as a CPU (microprocessor), a storage unit 12 such as a ROM (read-only memory) and a RAM (random access memory), and other peripheral circuits not shown in the figure, such as an I / O (input / output) interface. It should be noted that multiple ECUs with different functions, such as an engine control ECU, a travel motor control ECU, and a brake device ECU, can be separately provided, but for convenience, Figure 2 The controller 10 is shown in FIG. 1 as a collection of these ECUs.

[0043] The storage unit 12 can store high-precision map information (referred to as high-precision map information). The high-precision map information includes road location information, road shape (curvature, etc.) information, road slope information, intersection and fork location information, lane number (driving lane) information, lane width and each lane location information (lane center position, lane location boundary line information), location information of landmarks (signals, signs, buildings, etc.) marked on the map, and road surface contour information such as the bumps on the road surface. In addition to the two-dimensional map information described later, the storage unit 12 can also store various control programs, thresholds used in the programs, and setting information for vehicle-mounted detectors such as the laser radar 5 (including the steering information of the irradiation light described later).

[0044] It should be noted that, since highly accurate and detailed map information is not necessarily required in the embodiment, the storage unit 12 may not store detailed map information.

[0045] The computing unit 11 includes a recognition unit 111, a setting unit 112, a determination unit 113, and a driving control unit 114 as functional structures. Figure 2 As shown, the recognition unit 111, the setting unit 112 and the determination unit 113 are included in the outside recognition device 50. As described above, the outside recognition device 50 recognizes the outside conditions around the vehicle based on the detection data of the vehicle-mounted detectors such as the camera 4 and the laser radar 5. The recognition unit 111, the setting unit 112 and the determination unit 113 included in the outside recognition device 50 will be described in detail later.

[0046] In the automatic driving mode, the driving control unit 114 generates a target trajectory based on the external conditions around the vehicle recognized by the external recognition device 50, and controls the actuators AC so that the vehicle 101 drives along the target trajectory. It should be noted that in the manual driving mode, the driving control unit 114 controls the actuators AC based on the driving instructions (steering operation, etc.) from the driver obtained by the internal sensor group 3.

[0047] The laser radar 5 is further described.

[0048] <Detection area>

[0049] The laser radar 5 is installed toward the front of the vehicle 101 so that the area to be observed during driving is included in the FOV. The laser radar 5 receives light scattered by a solid object or the like irradiated with irradiation light (hereinafter sometimes referred to as return light), so the FOV of the laser radar 5 corresponds to the irradiation range and detection area of ​​the irradiation light. In other words, the irradiation point in the irradiation range corresponds to the detection point in the detection area.

[0050] In the embodiment, the road surface shape including the bumps, steps, and undulations of the road surface, three-dimensional objects located on the road RD (equipment associated with the road RD, such as signal machines, signs, ditches, walls, fences, guardrails, etc.), objects on the road RD (including other vehicles and obstacles on the road surface), and road markings set on the road surface are referred to as three-dimensional objects, etc. Road markings include white lines (including lines of different colors such as yellow), curb lines, road spikes, etc., which can be referred to as lane marks. In addition, objects pre-set as detection objects among three-dimensional objects, etc. are referred to as detection objects.

[0051] <Importance of irradiated light>

[0052] Figure 3 Schematic diagram for explaining the irradiation point of the irradiation light irradiated into the FOV by the laser radar 5. The laser radar 5 moves the position of the irradiation point by changing the projection angle of the irradiation light to the vertical direction or 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 is called the angular resolution.

[0053] In the three-dimensional coordinates composed of the x-axis, y-axis, and z-axis, the traveling direction of the host vehicle 101 corresponds to the positive direction of the x-axis, the horizontal left of the host vehicle 101 corresponds to the positive direction of the y-axis, and the vertical top corresponds to the positive direction of the z-axis. 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.

[0054] Generally speaking, the larger the size of the detection object is and the shorter the depth distance X from the host vehicle 101 to the detection object is (in other words, the closer the detection object is to the host vehicle 101), the larger the viewing angle for the detection object is, so even if the angular resolution of the laser radar 5 is set to a lower level, the detection object can be detected. On the contrary, the smaller the size of the detection object is and the longer the depth distance X is (in other words, the farther the detection object is from the host vehicle 101), the smaller the viewing angle for the detection object is, so when the angular resolution of the laser radar 5 is set to a higher level, it is difficult to detect the detection object. Therefore, the larger the size of the detection object is and the shorter the depth distance X is, the more the external recognition device 50 reduces the angular resolution of the laser radar 5 (increases the value), and the smaller the size of the detection object is and the longer the depth distance X is, the more the external recognition device 50 increases the angular resolution of the laser radar 5 (reduces the value).

[0055] By improving the angular resolution in the vertical direction, the intervals between irradiation points in the vertical direction within the FOV become narrower, the intervals between irradiation points become denser, and the number of irradiation points increases.

[0056] On the contrary, by reducing the angular resolution in the vertical direction, the intervals between irradiation points in the vertical direction within the FOV become wider, the intervals between irradiation points become sparse, and the number of irradiation points decreases.

[0057] The same is true for the angular resolution in the horizontal direction.

[0058] exist Figure 3 In the figure, "dense" means, for example, the interval in the vertical direction of the irradiation points (detection points) corresponding to an angular resolution of 0.05 degrees. "Intermediate" means, for example, the interval in the vertical direction of the irradiation points (detection points) corresponding to an angular resolution of 0.1 degrees. "Sparse" means, for example, the interval in the vertical direction of the irradiation points (detection points) corresponding to an angular resolution of 0.2 degrees.

[0059] exist Figure 3 , an example in which the angular resolution is switched to three levels is shown, but the present invention is not limited to three levels, and the angular resolution may be switched to two levels or four levels as appropriate.

[0060] The external recognition device 50 determines the necessary angular resolution based on, for example, the minimum size of the detection target (e.g., 15 cm) and the necessary depth distance (e.g., 100 m) specified in advance. The necessary 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 in motion needs to detect the road surface condition in the traveling direction at a distance farther than the braking distance, the value obtained by adding a specified margin to the braking distance is referred to as the necessary depth distance. The vehicle speed of the host vehicle 101 is detected by software processing such as SLAM using the sensor data of the vehicle speed sensor of the internal sensor group 3, the lidar 5, etc. The relationship between the vehicle speed and the necessary depth distance is stored in advance in the storage unit 12. 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 necessary depth distance corresponding to the vehicle speed.

[0061] 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 densities) in each area within the FOV, and controls the lidar 5 to sequentially irradiate the irradiation light to these irradiation points. Thus, the irradiation light from the lidar 5 is irradiated toward the set irradiation points (detection points).

[0062] The external recognition device 50 stores in the storage unit 12 the information indicating the positions of the set irradiation points (which may also be referred to as the steering information of the irradiation light) in correspondence with the position information indicating the traveling position of the host vehicle 101 in motion.

[0063] For example, when detecting a 15-cm detection target at 100 m in the traveling direction of the host vehicle 101 traveling at a vehicle speed of 100 km / h, the necessary 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 reduce the interval between the irradiation points within the FOV.

[0064] On the contrary, 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, the interval between the irradiation points within the FOV can be expanded by further reducing the angular resolution.

[0065] It should be noted that the actual number of irradiation points within the FOV is much larger than Figure 3The number of black circles shown in the figure is large. For example, when the FOV of the laser radar 5 is 120 degrees in the horizontal direction, the black circles corresponding to the irradiation points (detection points) in the horizontal direction are arranged at most 1200 when the angular resolution is set to 0.1 degrees in the entire horizontal direction. Similarly, when the FOV is 25 degrees in the vertical direction, the black circles corresponding to the irradiation points (detection points) in the vertical direction are arranged at most 500 when the angular resolution is set to 0.05 degrees in the entire vertical direction.

[0066] The outside world recognition device 50 suppresses the total number of irradiation points (detection points) by controlling the intervals between detection points, in other words, suppresses the total number of detection data used for recognition processing.

[0067] Specifically, in the area where the depth distance X in the FOV is shorter than the necessary depth distance, the viewing angle for the detection object becomes larger as described above, so the intervals between the detection points in the vertical and horizontal directions are increased to suppress the number of irradiation points. In addition, for the area corresponding to the blank in the FOV, since there is no detection object such as the road RD, the intervals between the irradiation points in the vertical and horizontal directions are increased to suppress the number of irradiation points. In this way, although the laser radar 5 as a vehicle-mounted detector has a low necessity to set the maximum angular resolution throughout the horizontal and vertical directions in the FOV (in other words, the intervals between the irradiation points are set denser throughout the FOV to set the maximum number of irradiation points), it is more necessary to set the maximum angular resolution in any area in the FOV.

[0068] Every time the external recognition device 50 scans the FOV with one frame of irradiation light, it controls the irradiation direction of the laser radar 5 to turn in the vertical direction and the horizontal direction to obtain Figure 3 The detection data of the detection point shown by the black circle is obtained Figure 1B Point cloud data as shown.

[0069] <Light deflection mechanism>

[0070] The laser radar 5 of 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.

[0071] Figure 4: is a schematic diagram illustrating the structure of the laser radar 5. The laser radar 5 includes, for example, a transceiver 51 of FMCW (frequency modulated continuous wave) mode, a vertical scanning mechanism 52, a horizontal scanning mechanism 53, and a control unit 54. The control unit 54 has a computing unit such as a processor, and a memory such as a ROM and a RAM. The computing unit executes a program stored in the memory, thereby performing signal transmission and reception between the laser radar 5 and the controller 10 and controlling the transceiver 51, the vertical scanning mechanism 52, and the horizontal scanning mechanism 53 (output of control signals, etc.).

[0072] The transceiver 51 includes a light source 511 and a detector 512. In addition, in the laser radar 5, the solid arrows indicate the light transmission path, and the dotted arrows indicate the light reception path.

[0073] <Vertical scanning mechanism>

[0074] Figure 5 is used to explain in more detail Figure 4 The block diagram of the transceiver 51 and the vertical scanning mechanism 52 of the laser radar 5 is shown in FIG. The vertical scanning mechanism 500 including the transceiver has a light source 511, a detector 512 which is a balanced photodiode (hereinafter referred to as BPD (Balanced Photodiode)), a first switch group 513, a waveguide intersection 515, a second switch group 516, and a projection lens 525. Hereinafter, the detector 512 is referred to as BPD512.

[0075] The light source 511 is a laser light source of Pch having a plurality of (P) lasers that emit irradiation light output to a measurement point within the FOV. The P lasers can output irradiation light at the same time or at separate times. The light source 511 may also include an amplifier that amplifies the light emitted by the laser light source. In addition, a spectrometer that distributes the light emitted by the laser light source into a plurality of channels may also be included. The amplifier is effective because it outputs irradiation light of a specified intensity to each channel when the optical power of each laser of the light source 511 is small and when the optical power is reduced by distributing the light to a plurality of channels.

[0076] BPD 512 is an optical receiver that detects interference signals of reference light and return light using two photodiodes with the same characteristics. In the embodiment, there are P sets of such optical receivers, which are the same number as the laser light sources of light source 511. That is, it is configured to simultaneously receive Pch return lights.

[0077] The first switch group 513 is an optical switch group having an input terminal of Pch and an output terminal of Q (= P×n)ch. For example, a 1×n switch group P is provided to selectively output the optical signal (hereinafter referred to as light) input from each input terminal to any one of n output destinations. Thus, the light of Pch input from the light source 511 is selectively output from the output terminal of Pch among the output terminals of Qch. It should be noted that n can be an odd number or an even number.

[0078] The first switch group 513 is formed by combining a plurality of optical switches such as Mach-Zehnder interference type as will be described later.

[0079] The waveguide intersection 515 has a waveguide of Qch formed on a silicon substrate. These waveguides are formed in such a way that the lights of different lasers from the light source 511 intersect on the substrate. Thus, for example, when the adjacent input ends of the waveguide intersection 515 input the lights from the same laser, the adjacent output ends of the waveguide intersection 515 output the lights from different lasers.

[0080] The second switch group 516 is an optical switch group having an input end of Qch and an output end of R(=Q×s)ch. For example, a 1×s switch having Q groups selectively outputs the light input from each input end to any one of s output destinations. Thus, the light of Qch input from the waveguide intersection 515 is selectively output from the output end of Qch among the output ends of Rch. It should be noted that in the embodiment, since the light source 511 is Pch, the light output from the second switch group 516 at the same time is Pch. It should be noted that s can be an odd number or an even number.

[0081] Similar to the first switch group 513 , the second switch group 516 is formed by combining a plurality of optical switches such as Mach-Zehnder interference type as described later.

[0082] The projection lens 525 is configured so that the R output ends of the second switch group 516 are arranged in its focal plane. The projection lens 525 may be composed of an optical member that functions as a lens in the direction in which at least the R output ends are arranged. The R beams of irradiation light (also called signal light) output from the R output ends are incident on different areas of the projection lens 525, respectively, and irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0083] <Overall structure of the branching section for output light>

[0084] Figure 6 It is an example from Figure 5Schematic diagram of the overall structure of the branching portion of the output light extracted from the illustrated vertical direction scanning mechanism 500. As an example, in the embodiment, the number of lasers of the light source 511 is set to P=8ch. In addition, the number of input ends of the first switch group 513 is set to P=8ch, and the number of output ends of the first switch group 513 is set to Q=64ch. Further, the number of input ends and output ends of the waveguide intersection 515 is set to Q=64ch. Furthermore, the number of input ends of the second switch group 516 is set to Q=64ch, and the number of output ends of the second switch group 516 is set to R=512ch. It should be noted that, Figure 6 The black oval shown schematically represents the 1×2 switch SW. Figure 7 and Fig. 9 The same is true for the black ellipse shown.

[0085] As described above, when the FOV in the vertical direction is set to 25 degrees and the angular resolution in the vertical direction is set to 0.05 degrees, the number of required irradiation points is 500. As an example, in the embodiment, a margin of +12 is provided on the basis of 500, and R=512 ch.

[0086] For the structure of each part, refer to Figure 7 to Figure 9 Further details are given.

[0087] Figure 7 It is used to illustrate Figure 6 FIG. 5 is a diagram of a light source 511 and a first switch group 513 in the overall configuration diagram of the branching portion of the output light illustrated in FIG.

[0088] The light source 511 is a P=8 ch light source including laser A, laser B, laser C, ..., laser G, and laser H.

[0089] The first switch group 513 is composed of a plurality of 1×2 switches SW that selectively output input light to any one of the 2ch output terminals, combined in a tree shape. In the embodiment, three layers (7) of 1×2 switches SW are combined in the eight lasers A to H. Thus, the light (light a to h) emitted by each of the lasers A to H is selectively output from one of the 8ch output terminals.

[0090] With the above structure, the first switch group 513 selectively outputs the 8-channel light input from the light source 511 from P (=8) output terminals among Q=64 (=8×8) output terminals.

[0091] It should be noted that the eight 1×2 switches SW provided at the input ends of the eight channels of the first switch group 513 are referred to as first-layer SWs. The sixteen switches provided on the right side (which may be referred to as the downstream side) of the first-layer SWs are referred to as second-layer SWs. In addition, the thirty-two switches provided on the right side (the downstream side) of the second-layer SWs are referred to as third-layer SWs.

[0092] Figure 8 It is explained in Figure 6 A diagram of the waveguide intersection 515 in the overall configuration diagram illustrated in . At the 64-channel input end of the waveguide intersection 515 , for example, 64 (=8×8) terminals in total are arranged to input 8 channels of light a to h from lasers A to H, respectively.

[0093] The waveguide intersection 515 has a waveguide with Q=64ch formed on a silicon substrate. In the embodiment, the waveguide of 64ch is formed by removing Figure 8 The waveguides of 62 channels, one channel each at the top and bottom, intersect with other waveguides on the substrate. Therefore, the arrangement order of light at the input end of the waveguide intersection 515 is different from the arrangement order of light at the output end of the waveguide intersection 515.

[0094] At the input end of the 64 channels of the waveguide intersection 515, the input position of light a is arranged at the input end of the first 8 channels from the top. The input position of light b is arranged at the input end of the next 8 channels. Similarly, the input positions of 8 channels of light from each laser are arranged in the order of light c, light d, light e, light f, light g, and light h.

[0095] At the output ends of the 64 channels of the waveguide intersection 515, the output positions of 1 channel of light a, light b, light c, light d, light e, light f, light g, and light h are arranged in order at the output ends of the first 8 channels from the top. The output positions of 1 channel of light a, light b, light c, light d, light e, light f, light g, and light h are also arranged in order at the output ends of the next 8 channels.

[0096] After that, the output positions of 1ch light a, light b, light c, light d, light e, light f, light g, and light h are arranged in sequence. Because of this structure, the output positions of light from each laser are repeatedly arranged 8 times in order from light a to light h.

[0097] Fig. 9 It is explained in Figure 6The second switch group 516 and the projection lens 525 in the overall structure diagram are shown in FIG. The second switch group 516 in the embodiment is formed by combining three layers (7) of 1×2 switch SW combinations in a tree-like manner at each input end of 64ch, thereby actually forming a 1×s (=8) switch. In other words, the light input to each input end of 64ch is selectively output from one of the output ends of the corresponding 8ch.

[0098] It should be noted that the 3-layer 1×2 switch SW set at each input end of 64 channels is set Fig. 9 The 64 switches on the left side (also called the upstream side) of the fourth layer SW are called the fourth layer SW. The 128 switches set on the right side (also called the downstream side) of the fourth layer SW are called the fifth layer SW. In addition, the 256 switches set on the right side (downstream side) of the fifth layer SW are called the sixth layer SW.

[0099] With the above configuration, the second switch group 516 having R (= 512) ch output terminals is configured to selectively output light input to each Q (= 64) ch input terminal from one of the corresponding 8 ch output terminals.

[0100] As described above, the R beams of irradiation light outputted from the R output terminals are incident on different areas of the projection lens 525. Then, the beams are irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0101] It should be noted that according to Fig. 9 It can be seen that light a, light b, light c, light d, light e, light f, light g, and light h are respectively incident on different areas of the projection lens 525. That is, laser A, laser B, laser C, laser D, laser E, laser F, laser G, and laser H respectively irradiate different irradiation points within the FOV. In other words, laser A, laser B, laser C, laser D, laser E, laser F, laser G, and laser H irradiate different areas within the FOV.

[0102] As described above, the vertical scanning mechanism 500 switches the incident position (also referred to as the area) of the illuminating light beam emitted from the output end of the second switch group 516 on the projection lens 525 by controlling the switching of the laser emitting light in the light source 511 and the optical switch of the first switch group 513 and the second switch group 516.

[0103] R channels of irradiation light beams corresponding to the R irradiation points arranged in the vertical direction within the FOV can be emitted from the output end of R (=512)ch of the second switch group 516. In an embodiment, the number of lasers that can emit light at the same time from the light source 511 is 8ch, so 8 beams of irradiation light can be emitted at the same time. The laser radar 5 makes the necessary lasers in the 8ch emit light in sequence by staggering the timing of the laser emission while switching the optical switches of the first switch group 513 and the second switch group 516, thereby scanning the irradiation light in the vertical direction. As an example, by causing the 8ch laser to emit light multiple times as needed, it is possible to emit light to the 8ch laser beams in the vertical direction. Figure 3 The irradiation points arranged in the vertical direction within the FOV, as exemplified by the black circles in the figure, emit beams of irradiation light. In other words, the light-emitting point can be intelligently changed according to the necessary irradiation points.

[0104] As 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 the three-dimensional point cloud data of the next frame is obtained. As an example, the laser radar 5 refers to the irradiation points (corresponding to the irradiation points in the FOV) pre-stored in the storage unit 12. Figure 3 The table data (the steering information of the irradiated light) showing the relationship between the switching states of the optical switches of the first switch group 513 and the second switch group 516 (the black circles) determines the switching states of the emitting laser and the optical switches of the first switch group 513 and the second switch group 516.

[0105] As in the embodiment, the vertical scanning mechanism 52 adopts a solid-state type, which can improve the output of the irradiated light in a specified range designated as ROI (Region of Interest) within the field of view, thereby improving the matching of the processing of extending the detection distance of the specified range, improving the angular resolution of the specified range, and thus improving the detection performance of objects, etc.

[0106] <Horizontal scanning mechanism>

[0107] exist Figure 4 In the embodiment, as an example, the horizontal scanning mechanism 53 reflects the irradiation light by a polygon mirror rotated by a motor, thereby controlling the beam direction of the irradiation light.

[0108] The required horizontal field angle of the laser radar 5 as a vehicle-mounted detector is, for example, 120 degrees. In addition, it is required to scan a range of 120 degrees at an angle resolution of 0.1 degrees and a certain prescribed speed. Therefore, in the embodiment, a mechanical scanning mechanism that can stably scan a wider range of swing angles than a solid-state scanning mechanism is used as the horizontal scanning mechanism 53 to change the irradiation light in the horizontal direction.

[0109] As a specific example of the number of irradiation points, when scanning a field angle of 120 degrees at an angular resolution of 0.1 degrees, irradiation light is irradiated to 1200 irradiation points in the horizontal direction, and scattered light is received from each irradiation point.

[0110] As described later, the horizontal angular resolution determined by the determination unit 113 corresponds to the horizontal interval of the detection points when the next frame of three-dimensional point cloud data is obtained. As an example, the laser radar 5 refers to the irradiation points (corresponding to the irradiation points) in the FOV stored in advance in the storage unit 12. Figure 3 The position of the polygonal reflector when the laser emits light is determined by using the table data (black circle in the figure) showing the relationship between the position of the polygonal reflector and the position of the polygonal reflector (the deflection information of the irradiated light).

[0111] <Structure of the external recognition device>

[0112] The outside world recognition device 50 will be described in detail.

[0113] Reference Figure 2 As described above, the external environment recognition device 50 includes the recognition unit 111 , the setting unit 112 , the determination unit 113 , and the laser radar 5 .

[0114] <Identification Department>

[0115] The recognition unit 111 generates three-dimensional point cloud data using the time-series detection data detected in the FOV of the laser radar 5 .

[0116] In addition, the recognition unit 111 recognizes the road structure in the traveling direction of the road RD on which the host vehicle 101 is traveling and the detection object on the road RD in the traveling direction based on the detection data measured by the laser radar 5. The road structure refers to, for example, a straight road, a curved road, a branch road, a tunnel entrance, etc.

[0117] Furthermore, the recognition unit 111 detects road markings by, for example, performing brightness filtering on data representing a flat road surface. In this case, the recognition unit 111 may determine that the road markings are road markings when the height of the road surface whose brightness exceeds a predetermined threshold is substantially the same as the height of the road surface whose brightness does not exceed the predetermined threshold.

[0118] <Identification of road structure>

[0119] An example of the recognition of the road structure performed by the recognition unit 111 is described. The recognition unit 111 recognizes the curb, wall, ditch, guardrail or road marking of the road RD in the forward direction contained in the generated point cloud data as the boundary lines RL and RB of the road RD. Figure 1A). In addition, the road structure of the traveling direction indicated by these boundary lines RL and RB is identified. As described above, the road markings include white lines (including lines of different colors), curb lines, road spikes, etc., and the markings made by these road markings define the driving lanes of the road RD. In the embodiment, the boundary lines RL and RB of the road RD defined by the above markings are called road markings.

[0120] The recognition unit 111 recognizes the area sandwiched by the boundary lines RL and RB as an area corresponding to the road RD. It should be noted that the method for recognizing the road RD is not limited to this, and other methods may be used for recognition.

[0121] In addition, the recognition unit 111 separates the generated point cloud data into point cloud data representing a flat road surface and point cloud data representing a three-dimensional object. For example, among the three-dimensional objects on the road in the direction of travel included in the point cloud data, the road surface shapes such as bumps, steps, and undulations whose size exceeds a specified value (e.g., 15 cm) and the objects whose horizontal and vertical sizes exceed the above specified values ​​are recognized as detection objects. 15 cm is an example of the size of the detection object and can be changed appropriately.

[0122] <Settings Department>

[0123] The setting unit 112 sets the vertical projection angle φ of the irradiation light for the laser radar 5. When the FOV of the laser radar 5 is 25 degrees in the vertical direction as described above, the vertical projection angle φ is set in the range of 0 to 25 degrees at intervals of 0.05 degrees. Similarly, the setting unit 112 sets the horizontal projection angle θ of the irradiation light for the laser radar 5. When the FOV of the laser radar 5 is 120 degrees in the horizontal direction as described above, the horizontal projection angle θ is set in the range of 0 to 120 degrees at intervals of 0.1 degrees.

[0124] The setting unit 112 sets the irradiation point within the FOV (corresponding to the angle resolution determined by the determination unit 113 described later) for the laser radar 5. Figure 3 As an example, the intervals between the irradiation points (detection points) in the FOV in the vertical direction and the horizontal direction correspond to the angular resolutions in the vertical direction and the horizontal direction, respectively.

[0125] <Decision Department>

[0126] The decision unit 113 determines the angular resolution set by the setting unit 112. Here, the angle of the irradiated light relative to the horizontal direction (for example, the downward angle relative to the horizontal direction is expressed as a negative number, and the upward angle is expressed as a positive number) is called the projection angle α in the vertical direction (it can also be called the vertical direction angle). First, the decision unit 113 calculates the projection angle α in the vertical direction of each depth distance X and the distance DL to the road surface point of each depth distance X. Specifically, the depth distance X is calculated based on the distance DL from the laser radar 5 to the road surface point measured by the laser radar 5 and the projection angle α set for the laser radar 5 during measurement. The decision unit 113 calculates the relationship between the calculated depth distance X and the vertical direction angle. In addition, the decision unit 113 calculates the relationship between the depth distance X and the distance DL. Further, the decision unit 113 calculates the relationship between the depth distance X and the vertical direction angular resolution based on the size of the detection object and the depth distance X. In this way, the vertical direction angular resolution is calculated based on the size of the detection object 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.

[0127] Next, the decision unit 113 determines the angular resolution in the vertical direction required for identifying the detection object of the above size. Figure 3 If the angular resolution in the vertical direction is less than the depth distance X of 0.1deg, 0.05deg, which is smaller than 0.1deg, is determined as the necessary angular resolution. In addition, if the angular resolution in the vertical direction is greater than 0.1deg and less than 0.2deg, 0.1deg, which is smaller than 0.2deg, is determined as the necessary angular resolution. Similarly, for the depth distance X with an angular resolution in the vertical direction of 0.2deg or more and less than 0.3deg, and the depth distance X with an angular resolution in the vertical direction of 0.3deg or more and less than 0.4deg, 0.2deg and 0.3deg, which are smaller, are determined as the necessary angular resolutions, respectively.

[0128] The determined necessary angular resolution in the vertical direction can be reflected as the intervals in the vertical direction between detection points when acquiring the next frame of three-dimensional point cloud data.

[0129] In addition, the determination unit 113 may determine the required horizontal angular resolution for identifying the detection object according to the size of the detection object and the depth distance X. The required horizontal angular resolution may also be reflected as the horizontal interval of the detection points when acquiring the next frame of three-dimensional point cloud data.

[0130] It should be noted that the necessary angular resolution in the horizontal direction may also be consistent with the necessary angular resolution in the vertical direction determined previously. In other words, on the same horizontal line as the detection point at which the necessary angular resolution in the vertical direction is determined to be 0.05deg, the necessary angular resolution in the horizontal direction is determined to be 0.05deg. Similarly, on the same horizontal line as the detection point at which the necessary angular resolution in the vertical direction is determined to be 0.1deg, the necessary angular resolution in the horizontal direction is determined to be 0.1deg. Furthermore, with respect to other necessary angular resolutions, on the same horizontal line as the detection point at which the necessary angular resolution in the vertical direction is determined, the necessary angular resolution in the horizontal direction is also determined to be the same value as the necessary angular resolution in the vertical direction.

[0131] <Generation of position data>

[0132] The external recognition device 50 maps the data indicating the position of the detection object detected based on the time-series point cloud data measured in real time by the laser radar 5 onto a two-dimensional map such as an xy plane to generate continuous position data. In the xy space, the information indicating the height Z is removed, and the information indicating the depth distance X and the horizontal distance Y is left.

[0133] The recognition unit 111 obtains the position information of the three-dimensional object on the two-dimensional map stored in the storage unit 12, and performs coordinate transformation around the position of the vehicle 101 to calculate the relative position of the three-dimensional object according to the moving speed and moving direction (e.g., azimuth) of the vehicle 101. Whenever the laser radar 5 obtains point cloud data through measurement, the recognition unit 111 performs coordinate transformation on the relative position of the three-dimensional object obtained based on the obtained point cloud data around the position of the vehicle 101, and records it on the two-dimensional map.

[0134] <Explanation of the flow chart>

[0135] Fig.10 is to show that according to a predetermined procedure Figure 2 A flowchart of an example of a process executed by the calculation unit 11 of the controller 10. Fig.10 The processing shown in the flowchart is repeated in units of predetermined cycles, for example, while the vehicle 101 is traveling in the automatic driving mode.

[0136] First, in step S10 , the calculation unit 11 causes the laser radar 5 to obtain three-dimensional point cloud data, and the process proceeds to step S20 .

[0137] In step S20 , the calculation unit 11 calculates the road surface slope and the maximum depth distance of the road RD in the traveling direction based on the point cloud data acquired by the laser radar 5 .

[0138] For example, the calculation unit 11 obtains point cloud data representing a flat road surface by detecting and separating data of three-dimensional objects on the road RD from the point cloud data of the detection points determined by the determination unit 113. The three-dimensional objects include obstacles on the road, curbs, walls, ditches, guardrails, etc. provided at both ends of the road RD, and other vehicles such as two-wheeled vehicles on the road.

[0139] Next, the calculation unit 11 calculates the road surface slope of the road RD based on the point cloud data representing the road surface. Since the calculation process of the road surface slope is well known, a detailed description is omitted. Furthermore, the calculation unit 11 calculates the maximum depth distance and enters step S30. The maximum depth distance is the farthest depth distance that can be detected by the laser radar 5.

[0140] In step S30 , the calculation unit 11 calculates the vertical projection angle α and the distance DL to the road surface point at each depth distance X, and the process 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.

[0141] In step S40, the calculation unit 11 calculates the required angular resolution for each depth distance X, and proceeds to step S50. The required angular resolution is the angular resolution required for detecting a detection object of a predetermined size. The relationship between the depth distance X and the angular resolution may be pre-stored in the storage unit 12.

[0142] In step S50, the calculation unit 11 determines the angular resolution in the vertical direction as the required angular resolution through the determination unit 113, and proceeds to step S60. The required angular resolution in the vertical direction determined here is reflected in the interval in the vertical direction of the detection points when acquiring the next frame of three-dimensional point cloud data.

[0143] In step S60, the decision unit 113 of the calculation unit 11 decides the horizontal angular resolution as the required angular resolution, and the process proceeds to step S70. The required horizontal angular resolution determined here is reflected in the horizontal interval of the detection points when acquiring the next frame of three-dimensional point cloud data.

[0144] In step S70, the calculation unit 11 determines the coordinates of the detection point. More specifically, the determination indicates that Figure 3 The coordinates of the positions of the detection points are exemplified by black circles.

[0145] The control unit 54 reflects the position of the detection point determined in step S70 as the steering information of the irradiation light of the laser radar 5 when acquiring the three-dimensional point cloud data of the next frame.

[0146] Furthermore, 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 is traveling, based on the detection data detected at the position of the detection point determined in step S70 .

[0147] It should be noted that, each time the computing unit 11 acquires point cloud data in step S10, it maps the relative position of the three-dimensional object, etc. obtained based on the point cloud data on a two-dimensional map of the xy plane, thereby generating two-dimensional continuous position data. Furthermore, the relative position of the three-dimensional object, etc. obtained based on the point cloud data can be transformed into coordinates with the position of the host vehicle 101 as the center, and recorded on the two-dimensional map.

[0148] In step S80, the operation unit 11 determines whether to end the processing. If the vehicle 101 continues to travel in the automatic driving mode, the operation unit 11 determines that step S80 is negative (S80: No), returns to step S10, and repeats the above-mentioned processing. By returning to step S10, the measurement of three-dimensional objects based on point cloud data is periodically repeated during the driving of the vehicle 101. On the other hand, if the vehicle 101 ends traveling in the automatic driving mode, the operation unit 11 determines that step S80 is positive (S80: Yes), and ends. Fig.10 processing.

[0149] The above-described embodiment has the following effects.

[0150] (1) The vertical scanning mechanism 500 as an optical signal switching module for the laser radar 5 comprises: a first switch group 513, which serves as an optical branching section for inputting optical signals (light a to light h) from lasers A to laser H as multiple light sources, respectively, and selectively switches the output destination of each optical signal to one of multiple output destinations of 8 channels; a waveguide intersection 515, which serves as a waveguide-type intersection and crosses at least a part of the multiple optical signals (light a to light h) output from the first switch group 513; and output terminals 1 to Q (=64) for individually outputting the multiple optical signals (light a to light h) output from the waveguide intersection 515.

[0151] In particular, since the waveguide intersection 515 is provided for intersecting the plurality of optical signals (light a, light b, ...) output from the first switch group 513, the vertical scanning mechanism 500 can output the optical signals (light a, light b, ...) intersected by the waveguide intersection 515. As a result, the optical signals (light a, light b, ...) output from the vertical scanning mechanism 500 can be made denser than when the waveguide intersection 515 is not provided. To explain in more detail, by changing the arrangement 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, and the positional relationship between the output ends of light a and light b can be changed.

[0152] If a multilayer optical switch such as an integrated optical switch is combined with the existing technology (a structure in which multiple demultiplexing elements are simply stacked), even if the optical signal output from the output end of the integrated optical switch can be densely packed, the large size of the integrated optical switch will hinder the miniaturization of the laser radar. Furthermore, since the power of the irradiated light decreases due to the internal loss of the integrated optical switch, it is difficult to meet the requirements of an on-vehicle detector (especially small size and long-distance measurement).

[0153] However, if the vertical scanning mechanism 500 of the embodiment which is not affected by the size and internal loss of the integrated optical switch is adopted, it is possible to realize miniaturization and long-distance measurement as a vehicle-mounted detector.

[0154] (2) In the vertical scanning mechanism 500 of (1) above, when focusing on the laser A and the laser B, the first switch group 513 includes: a first optical switch (for example, a 3-layer 1×2 switch SW for switching the optical path of the light a among the first to third layers of switches constituting the first switch group 513) for inputting the optical signal (light a) from the laser A as the first light source and selectively outputting the optical signal (light a) from one of the output destinations of the first predetermined number of eight channels; and a second optical switch (for example, a 3-layer 1×2 switch SW for switching the optical path of the light a among the first to third layers of switches constituting the first switch group 513). The 3-layer 1×2 switch SW for switching the optical path of light b in the first to third layers of switches of the switch group 513 inputs an optical signal (light b) from a laser B serving as a second light source, and selectively outputs the optical signal (light b) from one of the output destinations of 8 channels serving as a second prescribed number. The waveguide intersection 515 crosses at least a portion 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 (first prescribed number + second prescribed number = 16) channels.

[0155] With this configuration, the configurations (number of channels) of switches constituting the optical path of light a and the optical path of light b are substantially equal, and thus it is possible to suppress loss variation between the optical paths.

[0156] (3) In the vertical scanning mechanism 500 of the above-mentioned (2), the output ends of the (8+8) channels include at least a plurality of groups (groups of light a and light b) consisting of output ends for outputting light signals from laser A (light a) and output ends for outputting light signals from laser B (light b).

[0157] Because of this configuration, it is possible to use a plurality of lasers A and lasers B to project light to the irradiation points within the FOV of the laser radar 5, and each of the lasers A and laser B can project light to at least a plurality of irradiation points. As a result, the number of lasers that the laser radar 5 should have can be reduced compared to a case where each of the plurality of lasers projects light to only one irradiation point.

[0158] (4) The vertical scanning mechanism 500 of (2) or (3) above further comprises: a first predetermined number (8) of third optical switches (for example, three layers of 1×2 switches SW for switching the optical path of light a among the switches of the fourth to sixth layers constituting the second switch group 516), which receive an optical signal (light a) output from the first optical switch among the optical signals output from the waveguide intersection 515 and selectively output the optical signal from one of the output destinations of the third predetermined number (8) of channels; and a second predetermined number (8) of fourth optical switches (for example, three layers of 1×2 switches SW for switching the optical path of light b among the switches of the fourth to sixth layers constituting the second switch group 516), which receive an optical signal (light b) output from the first optical switch among the optical signals output from the waveguide intersection 515 and selectively output the optical signal from one of the output destinations of the third predetermined number (8) of channels.

[0159] In this way, by providing the third optical switch and the fourth optical switch on the downstream side of the waveguide intersection 515, the number of output ends of optical signals can be increased without increasing the number of intersections.

[0160] In addition, compared with the case where the third optical switch is provided on the upstream side of the waveguide intersection 515, the number of intersections of the waveguides in the waveguide intersection 515 can be suppressed to be small. That is, compared with the case where the number of optical signals at the output end of the third optical switch ((the first prescribed number + the second prescribed number) × the third prescribed number) of optical signals are crossed, the number of intersections is suppressed to be small by crossing the optical signals of (the first prescribed number + the second prescribed number), so that the area of ​​the chip constituting the waveguide intersection 515 can be reduced, the chip design can be facilitated, and the crosstalk and reflection can be reduced.

[0161] (5) In the vertical scanning mechanism 500 of (4) above, each of the first optical switch, the second optical switch, the third optical switch, and the fourth optical switch is formed by combining a plurality of 1×2 optical switches.

[0162] With this configuration, the vertical scanning mechanism 500 can be realized with a simple structure.

[0163] (6) In the vertical direction scanning mechanism 500 of (5) above, the signal lights of the channels of (first prescribed number + second prescribed number) × third prescribed number selectively outputted from the first prescribed number of third optical switches and the second prescribed number of fourth optical switches are incident on different areas of the projection lens 525 as the projection optical system. Specifically, the signal lights of the channels of (first prescribed number + second prescribed number) × third prescribed number are incident on different positions arranged in the vertical direction of the projection lens 525.

[0164] With this configuration, signal lights of (first predetermined number+second predetermined number)×third predetermined number of channels selectively output from the third optical switch can be projected to different irradiation points within the FOV.

[0165] The above-described embodiment can be modified in various forms. Modifications will be described below.

[0166] (Variant 1)

[0167] In the above embodiment, an example is described in which only the vertical scanning mechanism 500 of one of the first scanning unit and the second scanning unit adopts a solid-state scanning mechanism. Alternatively, the horizontal scanning mechanism 53 as the second scanning unit may also adopt a solid-state scanning mechanism, similar to the case of the vertical scanning mechanism 500.

[0168] Alternatively, a solid-state scanning mechanism may be used as the horizontal scanning mechanism 53 of only one of the first scanning unit and the second scanning unit.

[0169] It should be noted that, when only one of the first scanning unit and the second scanning unit adopts a solid-state scanning mechanism, it is preferable to adopt a vertical scanning mechanism 500 for the following reason.

[0170] That is, since the required vertical field angle (25 degrees in the above example) of the laser radar 5 as the vehicle-mounted detector is narrower than the horizontal field angle (120 degrees in the above example), and the range of the angle resolution of 0.05 degrees finer than 0.1 degrees in the field angle of 25 degrees is required to be narrower (for example, approximately 10 degrees), when the irradiation light with high angular resolution is irradiated only to 10 degrees in the field angle of 25 degrees, the number of irradiation points in the vertical direction (corresponding to the number R of output terminals of the second switch group 516) can be reduced from the above 512.

[0171] Another reason is that the scanning drive of the vertical scanning mechanism 500 can be stopped in advance while the horizontal scanning mechanism 53 controls the driving of the irradiated light in the horizontal direction, so the scanning speed in the vertical direction can be slower than the scanning speed in the horizontal direction.

[0172] Therefore, when a solid-state scanning mechanism is used for only one of the first scanning unit and the second scanning unit, the solid-state scanning mechanism, which is more durable against vibration and shock than a mechanical scanning mechanism, is used as the vertical scanning mechanism 500 .

[0173] (Variant 2)

[0174] The number of irradiation points within the FOV of the laser radar 5 (vertical direction 512, horizontal direction 1200), the number of lasers constituting the light source P (=8), the number of optical switches constituting the first switch group 513 (8+16+32=56), the number of output terminals of the first switch group 513 Q (=64), the number of optical switches constituting the second switch group 516 (7×64=448), and the number of output terminals of the second switch group 516 R (=512) are all examples and can be appropriately changed. Other examples are described in the following Modification 3.

[0175] (Variant 3)

[0176] In the above embodiment, the case is described in which the number of channels at the output end of the first optical switch (= the first prescribed number), the number of channels at the output end of the second optical switch (= the second prescribed number), the number of channels at the output ends of the third and fourth optical switches (= the third prescribed number), the number of the third optical switches (= the first prescribed number), and the number of the fourth optical switches (= the second prescribed number) are the same number (= 8).

[0177] In variant 3, a case where the first prescribed number, the second prescribed number, and the third prescribed number are not equal is described. As an example, a case where the first prescribed number (e.g., 6) and the second prescribed number (e.g., 5) are different and the third prescribed number (e.g., 8) is larger than the first prescribed number and the second prescribed number is described.

[0178] In variant example 3, the number of irradiation points within the FOV of the laser radar 5 is 504 in the vertical direction and 1200 in the horizontal direction, the number of lasers constituting the light source is P=12, the number of optical switches constituting the first switch group 513 is 12+24+15=51, the number of output ends of the first switch group 513 is Q=63, the number of optical switches constituting the second switch group 516 is 7×63=441, and the number of output ends of the second switch group 516 is R=504.

[0179] <Overall structure of the branching section for output light>

[0180] When referring to Figure 6 When explaining the structure of the modification example 3 in the schematic diagram of , the number of lasers of the light source 511 is set to P=12ch. In addition, the number of input ends of the first switch group 513 is set to P=12ch, and the number of output ends of the first switch group 513 is set to Q=63ch. Further, the number of input ends and output ends of the waveguide intersection 515 is set to Q=63ch. Then, the number of input ends of the second switch group 516 is set to Q=63ch, and the number of output ends of the second switch group 516 is set to R=504ch.

[0181] As described above, when the FOV in the vertical direction is set to 25 degrees and the angular resolution in the vertical direction is set to 0.05 degrees, the number of required irradiation points is 500. In the third modification, there is a margin of +4 on top of the 500, which is R=504 ch.

[0182] Reference Figure 11 to Figure 13 The structure of each part is further described in detail. It should be noted that Fig.11 and Fig.13 The black oval shown schematically represents the 1×2 switch SW.

[0183] Fig.11 Yes Description Figure 6 FIG. 5 is a diagram of a light source 511 and a first switch group 513 in the overall configuration diagram of the branching portion of the output light illustrated in FIG.

[0184] The light source 511 is a P=12 ch light source including laser A, laser B, laser C, ..., laser K, and laser L.

[0185] The first switch group 513 is composed of a plurality of 1×2 switches SW that selectively output input light to any one of the 2ch output terminals, combined in a tree shape. In Modification 3, five 1×2 switches SW are combined for each of the three lasers A, B, and L. Thus, the light (light a, light b, and light l) emitted by each of the lasers A, B, and L is selectively output from one of the 6ch output terminals.

[0186] In addition, four 1×2 switches SW are combined with each of the nine lasers C, D, ..., K. Thus, light (light c, light d, ..., light k) emitted by each of the lasers C, D, ..., K is selectively output from one of the output ends of the 5 channels.

[0187] With the above configuration, the first switch group 513 selectively outputs the 12 ch light input from the light source 511 from P (=12) output terminals among Q=63 (=3×6+9×5) output terminals.

[0188] It should be noted that the 12 1×2 switches provided at the input terminals of the 12 channels of the first switch group 513 are referred to as the first layer SW. The 24 switches provided on the right side (also referred to as the downstream side) of the first layer SW are referred to as the second layer SW. In addition, the 15 switches provided on the right side (downstream side) of the second layer SW are referred to as the third layer SW.

[0189] Fig.12 Yes Description Figure 6 A diagram of the waveguide intersection 515 in the overall structure diagram illustrated in FIG. A total of 63 (=6+6+9×5+6) terminals are arranged at the 63ch input ends of the waveguide intersection 515, wherein, for example, light a emitted by laser A is 6ch, light b emitted by laser B is 6ch, light c to light k emitted by laser C to laser K are 5ch each, and light l emitted by laser L is 6ch.

[0190] The waveguide intersection 515 has a waveguide with Q=63ch formed on a silicon substrate. In Modification 3, the waveguide of 63ch is formed in Fig.12 The waveguides of 61 channels excluding the upper and lower channels intersect with other waveguides on the substrate. Therefore, the arrangement order of light at the input end of the waveguide intersection 515 is different from the arrangement order of light at the output end of the waveguide intersection 515.

[0191] At the output ends of the 63 channels of the waveguide intersection 515, for example, at the output ends of the first 6 channels, 1 channel of light a, light b, light c, light d, light e, and light f are arranged. At the output ends of the next 8 channels, 1 channel of light a, light b, light g, light h, light i, light j, light k, and light l are arranged. At the output ends of the next 12 channels, 1 channel of 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 arranged.

[0192] At the output end of the next 12 channels, 1 channel of 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 arranged. At the output end of the next 12 channels, 1 channel of 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 arranged.

[0193] At the output end of the next 7 channels, 1 channel of light a, light b, light c, light d, light e, light f, and light 1 is arranged. At the output end of the last 6 channels, 1 channel of light g, light h, light i, light j, light k, and light 1 is arranged.

[0194] Fig.13 Yes Description Figure 6. The second switch group 516 and the projection lens 525 in the overall structure diagram are shown in FIG. The second switch group 516 of the modification 3 is formed by combining three layers (7) of 1×2 switch SW combinations in a tree-like manner at each input end of 63ch, thereby actually forming a 1×s (=8) switch. In other words, the light input to each input end of 63ch is selectively output from one of the output ends of the corresponding 8ch.

[0195] It should be noted that among the three layers of 1×2 switches SW provided at each input end of 63 channels, the switches provided at Fig.13 The 63 switches on the left side (also called the upstream side) of the fourth layer SW are called the fourth layer SW. The 126 switches set on the right side (also called the downstream side) of the fourth layer SW are called the fifth layer SW. In addition, the 252 switches set on the right side (downstream side) of the fifth layer SW are called the sixth layer SW.

[0196] With the above configuration, the second switch group 516 having the output terminal of R (= 504) ch is configured to selectively output light input to each input terminal of Q (= 63) ch from one of the output terminals of the corresponding 8 ch.

[0197] As described above, the R channels of irradiation light beams output from the R output terminals are incident on different regions of the projection lens 525. Then, the beams are irradiated to different irradiation points within the FOV via the horizontal scanning mechanism 53.

[0198] It should be noted that according to Fig.13 It can be seen that 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 areas 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 respectively 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 irradiate different areas within the FOV.

[0199] As described above, the vertical scanning mechanism 500 controls the switching of the laser emitting light in the light source 511 and the optical switch of the first switch group 513 and the second switch group 516, thereby switching the incident position (also referred to as the area) on the projection lens 525 where the light beam of illuminating light emitted from the output end of the second switch group 516 is incident.

[0200] From the output end of R (= 504)ch of the second switch group 516, R beams of irradiation light corresponding to the R irradiation points arranged in the vertical direction within the FOV can be emitted. In variant example 3, the number of lasers that can emit light at the same time from the light source 511 is 12ch, so the number of beams of irradiation light that can be emitted at the same time is 12ch. The laser radar 5 sequentially emits the necessary lasers in the 12ch by staggering the emission timing of the lasers while switching the optical switches of the first switch group 513 and the second switch group 516, thereby scanning the irradiation light in the vertical direction. As an example, when the 12ch laser is emitted 42 times, 504 beams of irradiation light arranged in the vertical direction within the FOV can be emitted.

[0201] According to the modification example 3 described above, the following effects are obtained.

[0202] The laser radar 5 includes: a scanning mechanism 500 in the vertical direction, which serves as a first scanning unit and irradiates and scans light signals (light a to light l) in the vertical direction which is a first direction; and a scanning mechanism 53 in the horizontal direction, which serves as a second scanning unit and irradiates and scans light signals (light a to light l) in the horizontal direction which is a second direction intersecting the vertical direction. The laser radar 5 functions as a vehicle-mounted detector that irradiates and scans light signals (light a to light l) into the FOV to detect external conditions.

[0203] When describing with attention to the optical signals from laser B and laser C among lasers A to laser L, the vertical scanning mechanism 500 of at least one of the first scanning unit and the second scanning unit comprises: a first optical switch (a general term for the first to third layers SW of the optical path for switching light b in the first switch group 513), which inputs the optical signal (light b) from laser B as the first light source, and selectively outputs the optical signal (light b) from one of the output ends of the m1 channel (for example, 6); and a second optical switch (a general term for the first to third layers SW of the optical path for switching light c in the first switch group 513), which inputs the optical signal (light c) from laser C as the second light source, and selectively outputs the optical signal (light c) from one of the output ends of the m2 channel (for example, 5). ); m1 third optical switches (a general term for the fourth to sixth layers SW of the optical path for switching light b in the second switch group 516), which are used to input the optical signal (light b) output from the first optical switch and selectively output the optical signal (light b) from one of the output ends of the s channel (for example, 8); m2 fourth optical switches (a general term for the fourth to sixth layers SW of the optical path for switching light c in the second switch group 516), which are used to input the optical signal (light c) output from the second optical switch and selectively output the optical signal (light c) from one of the output ends of the s channel (for example, 8); and a waveguide intersection 515, which is a waveguide-type intersection and causes the optical signal (light b) output from the first optical switch and at least a part of the optical signal (light c) output from the second optical switch to intersect.

[0204] In particular, since the waveguide intersection 515 is provided to cross the optical signals (light b, light c), the vertical scanning mechanism 500 can output the optical signals (light b or light c) crossed by the waveguide intersection 515. As a result, the optical signals (light b and light c) output from the vertical scanning mechanism 500 can be made denser than when the waveguide intersection 515 is not provided. To explain in more detail, by changing the arrangement order of the optical signals output from the output end of the vertical scanning mechanism 500, for example, the output end of light b and the output end of light c can be brought closer, and the positional relationship between the output ends of light b and light c can be changed.

[0205] If a multilayer optical switch such as an integrated optical switch is combined with the prior art (a structure in which multiple demultiplexing elements are simply stacked), even if the optical signal output from the output end of the integrated optical switch can be densely packed, the excessive size of the integrated optical switch will hinder the miniaturization of the laser radar. Furthermore, since the internal loss of the integrated optical switch causes the irradiation light power to decrease, it is difficult to meet the requirements of an on-vehicle detector (especially small size, long-distance measurement, etc.).

[0206] However, if a laser radar 5 of an embodiment that is not affected by the size and internal loss of an integrated optical switch is adopted, miniaturization as a vehicle-mounted detector, long-distance measurement, etc. can be achieved.

[0207] The above description is merely an example, and the above embodiment and modified examples do not limit the present invention unless the features of the present invention are impaired. One or more of the above embodiment and modified examples can be arbitrarily combined.

[0208] The present invention can meet the demand for an optical signal switching module for laser radar.

[0209] The present invention has been described above in conjunction with preferred embodiments, but it should be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the claims.

Claims

1. An optical signal switching module, an optical signal switching module (500) for a laser radar (5), characterized in that: have: An optical branching unit (513) for inputting optical signals from a plurality of light sources respectively and selectively switching an output destination of each optical signal to one of the output destinations of a plurality of channels; a waveguide type intersection portion (515) for intersecting at least a portion of the plurality of optical signals output from the optical branching portion (513); as well as Output ends of multiple channels individually output the multiple optical signals output from the intersection (515).

2. The optical signal switching module according to claim 1, characterized in that: The optical branching unit (513) comprises: a first optical switch for inputting an optical signal from a first light source and selectively outputting the optical signal from one of output destinations of a first prescribed number of channels; and a second optical switch for inputting an optical signal from a second light source and selectively outputting the optical signal from one of output destinations of a second prescribed number of channels; The intersection portion (515) crosses at least a portion of the optical signal output from the first optical switch and the optical signal output from the second optical switch. The output terminal includes a number of channels represented by the sum of the first prescribed number and the second prescribed number.

3. The optical signal switching module according to claim 2, characterized in that: The output ends of the channels represented by the sum include a plurality of groups consisting of output ends that output the optical signal from the first light source and output ends that output the optical signal from the second light source.

4. The optical signal switching module according to claim 2 or 3, characterized in that: Also available: The first prescribed number of third optical switches are configured to receive the optical signal output from the first optical switch among the optical signals output from the intersection, and selectively output the optical signal from one of the output destinations of the third prescribed number of channels; and The second prescribed number of fourth optical switches receives the optical signal output from the second optical switch among the optical signals output from the intersection (515), and selectively outputs the optical signal from one of the output destinations of the third prescribed number of channels.

5. The optical signal switching module according to claim 4, characterized in that: 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 1×2 optical switches.

6. The optical signal switching module according to claim 5, characterized in that: The first optical switch, the second optical switch, the third optical switch and the fourth optical switch are respectively composed of a plurality of the 1×2 optical switches, so that signal lights of channels of a number represented by the product of the sum and the third specified number selectively output from the first specified number of the third optical switches and the second specified number of the fourth optical switches are respectively incident on different areas of the projection optical system (525).

7. The optical signal switching module according to claim 6, characterized in that: The signal lights are respectively incident on different positions arranged in the vertical direction of the projection optical system (525).

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