Optical path system and laser radar

Abstract

The present invention discloses an optical path system and a laser radar, wherein the optical path system comprises a first optical path and a second optical path, and the vertical resolution and refresh rate can be improved by the optical path system. The laser radar comprises a laser emission source, a galvanometer or a multi-faceted reflective prism, an optical path system, a horizontal rotating structure, and a motor control module. The use of a laser emission source can greatly reduce the cost and the calibration workload. At the same time, a rotating multi-faceted reflective prism or a galvanometer and the optical path system are used, and the laser beams distributed in the horizontal and vertical directions can be many, thereby improving the horizontal and vertical resolution of the laser radar, and meeting the technical parameter requirements of a multi-line laser radar of a multi-channel transmitter. The horizontal rotating structure is driven to rotate by the motor control module, thereby driving the laser emission source and the galvanometer or the multi-faceted reflective prism to rotate synchronously, thereby realizing 360° three-dimensional scanning. This invention is used in the detection field.

Description

Technical Field

[0001] The present invention relates to the field of detection, and in particular to an optical path system and a laser radar. Background Art

[0002] Currently in the fields of autonomous driving, the laser radars in the existing public technology are mainly divided into two categories. The first category is rotating multi-line laser radar, and the second category is non-rotating laser radar, namely solid-state laser radar.

[0003] The first type uses a mechanical rotation method to achieve three-dimensional scanning, which can meet the technical requirements of unmanned driving for a horizontal resolution of 0.1 degrees (360 degrees), a vertical resolution of 0.2 to 0.3 degrees (15 degrees up and down), and a refresh rate of 10 to 20 frames. However, it requires multiple laser transmitters and receivers and a horizontal rotation speed of 600 revolutions per minute. Each transmitter and receiver must be calibrated for mass production, which requires large manpower investment and low product yield. Therefore, the cost of laser radars using multiple laser transmitters in existing public technologies is very high.

[0004] There are three types of second-class solid-state lidars. The first is a MEMS (micro-electromechanical system) solution that uses a tiny MEMS scanning mirror to control the laser beam. The other uses a technology called optical phased array to control the laser beam without any moving parts.

[0005] The third type is called flash imaging LiDAR, which does not require beam steering, and only needs one flash to illuminate the entire scene, and then detects the reflected light through a two-dimensional array image sensor similar to a digital camera. However, the second type of solid-state LiDAR can only scan in one direction, not 360 degrees. It must be four such solid-state radars to achieve the effect of the first type of LiDAR, and only the first type of technology is relatively mature, so the cost cannot be significantly reduced and mass-produced.

[0006] Invention patent CN107153185a discloses a laser radar and a laser radar control method, which uses a vertical galvanometer and a horizontal rotating structure to complete three-dimensional scanning, and uses a transmitter to realize vertical scanning through a galvanometer, replacing multiple transmitters to reduce costs and structural complexity. However, since unmanned driving requires a laser radar with a horizontal resolution of 0.1 degrees and a refresh rate of 10 frames or more, and the measurement distance must reach 200m, according to this technical requirement, the time for each 0.1 degree scan in the horizontal direction is 27us, and each measurement time is at least 2us. Only 13 measurements can be made in the vertical direction, that is, the vertical resolution can only be 2.2 degrees. Therefore, the technical parameter requirements of the first type of multi-transmitter / receiver laser radar are not met, and the above-mentioned first type of laser radar cannot be completely replaced. Summary of the invention

[0007] The object of the present invention is to provide a method for reducing the cost and calibration workload of a laser radar, and to improve an optical path system and a laser radar of a vertical resolution.

[0008] The technical solution adopted by the present invention is:

[0009] An optical path system, comprising:

[0010] a first optical path, wherein the first optical path comprises a first reflector, a first beam splitter A, a first beam splitter B, and a first beam splitter C, and light entering the first optical path is reflected by the first reflector and passes through the first beam splitter A, the first beam splitter B, and the first beam splitter C in sequence, and the light entering the first beam splitter A, the first beam splitter B, and the first beam splitter C is split into two mutually perpendicular beams;

[0011] The second optical path comprises a second reflector, a second beam splitter A, a second beam splitter B, and a second beam splitter C. The light entering the second optical path is reflected by the second reflector and passes through the second beam splitter A, the second beam splitter B, and the second beam splitter C in sequence. The light entering the second beam splitter A, the second beam splitter B, and the second beam splitter C is split into two beams of light perpendicular to each other. The first reflector and the second reflector are arranged in parallel.

[0012] A laser radar, comprising:

[0013] A laser emission source for emitting laser light, wherein the laser emission source is composed of at least one laser emitter;

[0014] A galvanometer or a multi-faceted reflective prism, wherein the galvanometer or the multi-faceted reflective prism is used to change the optical path direction of the outgoing laser in the vertical direction;

[0015] As described above, the optical path system is used to divide the light reflected by the galvanometer or multi-faceted reflective prism into at least two directions, and the galvanometer or multi-faceted reflective prism is in the same straight line as the first reflector and the second reflector;

[0016] A horizontal rotating structure, the galvanometer or multi-faceted reflective prism and the laser emission source are mounted on the horizontal rotating structure, and the horizontal rotating structure is used to drive the galvanometer or multi-faceted reflective prism and the laser emission source to rotate synchronously horizontally;

[0017] A motor control module is arranged below the horizontal rotating structure, and the motor control module drives the horizontal rotating structure to rotate.

[0018] As a further improvement of the technical solution of the present invention, an angle measurement system is installed before the first reflector of the first optical path and before the second reflector of the second optical path, and the angle measurement system is used to determine the emission angle of the laser in the vertical direction.

[0019] As a further improvement of the technical solution of the present invention, the angle measurement system is a position sensitive detector.

[0020] As a further improvement of the technical solution of the present invention, it also includes a plurality of receivers, each of which is installed on a shell at equal intervals.

[0021] As a further improvement of the technical solution of the present invention, a focusing unit is provided before the receiver, and the focusing unit focuses the reflected laser to be received by the receiver.

[0022] As a further improvement of the technical solution of the present invention, the receiver is an avalanche diode.

[0023] As a further improvement of the technical solution of the present invention, it also includes a beam combining unit, which combines the lasers emitted by each laser emitter into one optical path for emission.

[0024] As a further improvement of the technical solution of the present invention, it also includes a collimating unit, which is arranged between the laser emission source and the multi-faceted reflective prism or the galvanometer, and is used to collimate the outgoing laser emitted by the laser emission source.

[0025] The beneficial effects of the present invention are as follows: the optical path system and the laser radar, the optical path system includes a first optical path and a second optical path, the vertical resolution and refresh rate can be improved by the optical path system, the laser radar includes a laser emission source, a galvanometer or a multi-faceted reflective prism, an optical path system, a horizontal rotation structure, and a motor control module. The use of a laser emission source can greatly reduce the cost and calibration workload, and at the same time, a rotating cylindrical multi-faceted reflective prism or a galvanometer and the optical path system are used, so that there can be a large number of laser light beams distributed in the horizontal and vertical directions, thereby improving the horizontal and vertical resolution of the laser radar and meeting the technical parameter requirements of a multi-line laser radar with a multi-channel transmitter. The horizontal rotation structure is driven to rotate by the motor control module, thereby driving the laser emission source and the galvanometer or the multi-faceted reflective prism to rotate synchronously, thereby realizing 360° three-dimensional scanning. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of a laser radar according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the optical path system of an embodiment of the present invention. DETAILED DESCRIPTION

[0029] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0031] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0033] Reference Figure 2 , an optical path system, comprising a first optical path 1 and a second optical path 2. The first optical path 1 comprises a first reflector 11, a first beam splitter A12, a first beam splitter B13, and a first beam splitter C14. The light entering the first optical path 1 is reflected by the first reflector 11 and passes through the first beam splitter A12, the first beam splitter B13, and the first beam splitter C14 in sequence. The light entering the first beam splitter A12, the first beam splitter B13, and the first beam splitter C14 is split into two mutually perpendicular beams. The second optical path 2 comprises a second reflector 21, a second beam splitter A22, a second beam splitter B23, and a second beam splitter C24. The light entering the second optical path 2 is reflected by the second reflector 21 and passes through the second beam splitter A22, the second beam splitter B23, and the second beam splitter C24 in sequence. The light entering the second beam splitter A22, the second beam splitter B23, and the second beam splitter C24 is split into two mutually perpendicular beams. The first reflector 11 and the second reflector 21 are arranged in parallel. This optical path system can radiate light from eight directions through the first optical path 1 and the second optical path 2 to scan the object to be measured, which can effectively improve the vertical resolution and refresh rate.

[0034] Reference Figure 1 and Figure 2 A laser radar includes a laser emission source 3, a galvanometer or a multi-faceted reflective prism, an optical path system, a horizontal rotation structure 4, and a motor control module 5. Using a laser emission source 3 can effectively reduce the cost of the laser radar and improve the vertical resolution of the laser radar.

[0035] Among them, the laser emission source 3 is used to emit laser, and the laser emission source 3 is composed of at least one laser emitter, which can increase the emission frequency. The galvanometer or multi-faceted reflective prism is used to change the optical path direction of the emitted laser in the vertical direction. The optical path system is used to divide the light reflected by the galvanometer or multi-faceted reflective prism into at least two directions for emission, and the galvanometer or multi-faceted reflective prism is on the same straight line as the first reflector 11 and the second reflector 22. The galvanometer or multi-faceted reflective prism and the laser emission source 3 are installed on the horizontal rotating structure 4, and the horizontal rotating structure 4 is used to drive the galvanometer or multi-faceted reflective prism and the laser emission source 3 to rotate synchronously horizontally. The motor control module 5 is arranged below the horizontal rotating structure 4, and the motor control module 5 drives the horizontal rotating structure 4 to rotate horizontally, driving the galvanometer or multi-faceted reflective prism installed on the horizontal rotating structure 4 and the laser emission source 3 to rotate synchronously. When in use, the speed of the motor control module 5 can be adjusted as needed to adjust the rotation speed.

[0036] An angle measurement system is installed before the first reflector 11 of the first optical path 1 and before the second reflector 21 of the second optical path 2. The angle measurement system is used to determine the emission angle of the laser in the vertical direction. Further, the angle measurement system is a position sensitive detector, such as PSD, PIN, APD, CMOS / CCD, etc. In actual operation, a beam splitter is arranged on the optical path before the first reflector 11 and the second reflector 21 are reflected, and an angle measurement system is arranged and installed on the branch path split by the beam splitter to directly measure the emission angle of the laser in the vertical direction.

[0037] In this embodiment, a plurality of receivers 6 are also included, and each receiver 6 is installed on a housing 7 at equal intervals. It can be understood that in order to better receive information, a focusing unit is provided before the receiver 6, and the focusing unit focuses the reflected laser to be received by the receiver 6. Further, the receiver 6 is an avalanche diode. Figure 2 In this embodiment, eight receivers are evenly arranged at equal distances on the inner side of the housing 7. The first reflector 11, the first beam splitter A12, the first beam splitter B13, the first beam splitter C14, the second reflector 21, the second beam splitter A22, the second beam splitter B23, and the second beam splitter C24 are all arranged between the intervals of adjacent receivers 6.

[0038] The optical path system is embedded in the horizontal rotating structure 4 driven by the motor control module 5. The horizontal rotating structure 4 drives the light beams to rotate in multiple directions to achieve continuous multi-point three-dimensional spatial scanning of environmental targets. By combining this optical path system with the horizontal rotating structure 4 and a galvanometer or a multi-faceted reflective prism, the technical requirements of unmanned driving for a horizontal resolution of 0.1 degrees (360 degrees), a vertical resolution of 0.2 to 0.3 degrees (15 degrees up and down) and a refresh rate of 10 to 20 frames can be met.

[0039] In one embodiment, a beam combining unit and a collimating unit are further included. The beam combining unit combines the lasers emitted by each laser emitter into one optical path for emission. The collimating unit is arranged between the laser emission source 3 and the multi-faceted reflective prism or galvanometer. The collimating unit is used to collimate the outgoing laser emitted by the laser emission source 3.

[0040] This laser radar uses a laser emission source 3 to greatly reduce the cost and calibration workload. At the same time, a rotating galvanometer or a multi-faceted reflective prism and an optical path system are used. There can be many laser beams distributed in the horizontal and vertical directions, which improves the horizontal and vertical resolution of the laser radar and meets the technical parameter requirements of a multi-line laser radar with a multi-channel transmitter. The horizontal rotating structure 4 is driven to rotate by the motor control module 5, thereby driving the laser emission source 3 and the multi-faceted reflective prism or galvanometer to rotate, thereby realizing 360° three-dimensional scanning. The optical path system and the horizontal rotating structure 4 act synchronously, which greatly improves the scanning frequency.

[0041] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. An optical path system, characterized in that: include: a first optical path, wherein the first optical path comprises a first reflector, a first beam splitter A, a first beam splitter B, and a first beam splitter C, and light entering the first optical path is reflected by the first reflector and passes through the first beam splitter A, the first beam splitter B, and the first beam splitter C in sequence, and the light entering the first beam splitter A, the first beam splitter B, and the first beam splitter C is split into two mutually perpendicular beams; a second optical path, wherein the second optical path comprises a second reflector, a second beam splitter A, a second beam splitter B, and a second beam splitter C, and the light entering the second optical path is reflected by the second reflector and passes through the second beam splitter A, the second beam splitter B, and the second beam splitter C in sequence, and the light entering the second beam splitter A, the second beam splitter B, and the second beam splitter C is split into two mutually perpendicular beams; The first reflector and the second reflector are arranged in parallel; the light passing through the first light path and the second light path is emitted from eight directions.

2. A laser radar, characterized in that: include: A laser emission source for emitting laser light, wherein the laser emission source is composed of at least one laser emitter; A galvanometer or a multi-faceted reflective prism, wherein the galvanometer or the multi-faceted reflective prism is used to change the optical path direction of the outgoing laser in the vertical direction; The optical path system according to claim 1, wherein the optical path system is used to separate the light reflected by the galvanometer or multi-faceted reflective prism into at least two directions, wherein the galvanometer or multi-faceted reflective prism is in the same straight line as the first reflector and the second reflector; A horizontal rotating structure, the galvanometer or multi-faceted reflective prism and the laser emission source are mounted on the horizontal rotating structure, and the horizontal rotating structure is used to drive the galvanometer or multi-faceted reflective prism and the laser emission source to rotate synchronously horizontally; A motor control module is arranged below the horizontal rotating structure, and the motor control module drives the horizontal rotating structure to rotate.

3. The laser radar according to claim 2, characterized in that: An angle measurement system is installed before the first reflector of the first optical path and before the second reflector of the second optical path. The angle measurement system is used to determine the emission angle of the laser in the vertical direction.

4. The laser radar according to claim 3, characterized in that: The angle measurement system is a position sensitive detector.

5. The laser radar according to claim 2, characterized in that: It also includes a plurality of receivers, each of which is installed on a shell at equal intervals.

6. The laser radar according to claim 5, characterized in that: A focusing unit is arranged before the receiver, and the focusing unit focuses the reflected laser light to be received by the receiver.

7. The laser radar according to claim 6, characterized in that: The receiver is an avalanche diode.

8. The laser radar according to any one of claims 2 to 7, characterized in that: It also includes a beam combining unit, which combines the lasers emitted by each laser emitter into one optical path for emission.

9. The laser radar according to any one of claims 2 to 7, characterized in that: It also includes a collimating unit, which is arranged between the laser emission source and the multi-faceted reflective prism or the galvanometer, and is used for collimating the outgoing laser emitted by the laser emission source.

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