Optical path system and laser radar

Abstract

The present invention discloses an optical path system and a laser radar. The optical path system emits N synchronous light beams into a rotating polyhedral prism, and forms N scanning lights through the rotating polyhedral prism. The scanning lights are reflected by a fixed polyhedral prism to form N vertical scanning lights that are synchronously emitted from the center of a circle toward the outside. Compared with a single light source, the refresh rate is increased by N times. When the refresh rate is maintained at 1 / N, the scanning time of each horizontal angle is correspondingly increased, the vertical scanning time within the horizontal scanning angle is increased, and the vertical resolution is increased. This laser radar includes N (at least two) laser transmitters, an optical path system, a horizontal rotation structure, and a motor control module. The laser emitted by the laser transmitter emits N vertical scanning lights through the optical path system. When the refresh rate remains unchanged, the rotation speed can be reduced, and the scanning time of each horizontal angle is increased, thereby increasing the vertical scanning time within the horizontal scanning angle, and increasing the vertical resolution by multiples.

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] In the field of autonomous driving, the higher the horizontal resolution, vertical resolution and refresh rate of the laser radar, the better the safety of autonomous driving. The laser radar in the existing technology is mainly divided into two categories, the first category is rotating multi-line laser radar, and the second category is non-rotating laser radar, that is, solid-state laser radar.

[0003] The first type uses mechanical rotation to achieve three-dimensional scanning, which can meet the technical requirements of unmanned driving for 0.1° horizontal resolution (360°), 0.2-0.3° vertical resolution (up and down 15°) and 10-20 frame refresh frequency, but the resolution in the vertical direction is proportional to the number of laser transmitters and receivers. For example, if the 30° field of view is to be subdivided into 128 parts in the vertical direction, 128 laser transmitters and 128 receivers are required, and each transmitter and receiver must be calibrated during mass production, which requires large manpower investment and low product yield. Therefore, the mechanical rotating laser radar using multiple lasers in the existing technology is very expensive.

[0004] There are three types of second-class solid-state LiDARs. The first is a MEMS (micro-electromechanical system) solution that uses a micro-MEMS scanning mirror to control the laser beam. Another type uses a technology called optical phased array to control the laser beam without any moving parts. The third type is called flash imaging LiDAR, which does not require beam steering and can illuminate the entire scene with just one flash. The reflected light is then detected by a two-dimensional array image sensor similar to a digital camera. However, the second-class solid-state LiDAR can only scan in one direction and cannot scan 360°. Multiple such solid-state radars must be used to achieve the effect of the first-class LiDAR. And only the first-class technology is relatively mature, so the cost cannot be significantly reduced and mass-produced.

[0005] 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° 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° scan in the horizontal direction is 27μs, and each measurement time is at least 2μs. Only 13 measurements can be made in the vertical direction, that is, the vertical resolution can only be 2.2°, so it does not meet the technical parameter requirements of the first type of multi-transmitter / receiver laser radar and cannot completely replace the above-mentioned first type of laser radar. Summary of the invention

[0006] The object of the present invention is to provide an optical path system with improved vertical resolution.

[0007] The invention also provides a laser radar comprising the optical path system.

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

[0009] According to the optical path system of the first aspect of the present invention, it includes N synchronous light sources that divide the circumference equally, a rotating polyhedron prism and a fixed polyhedron prism. Light enters the rotating polyhedron prism and forms scanning light after being reflected or refracted by the rotating polyhedron prism. The scanning light is reflected by the fixed polyhedron prism to form N vertical scanning lights that are synchronously emitted from the center of the circle to the outside.

[0010] The beneficial effects of the present invention are as follows: in this optical path system, N synchronous light rays are incident on a rotating polygonal prism, and N scanning lights are formed after passing through the rotating polygonal prism. The scanning lights are reflected by a fixed polygonal prism to form N vertical scanning lights that are synchronously emitted from the center of the circle to the outside. The refresh rate will be increased by N times relative to that of one light source. While maintaining a refresh rate of 1 / N, the scanning time of each horizontal angle is correspondingly increased, thereby increasing the vertical scanning time within the horizontal scanning angle, and increasing the resolution in the vertical direction by multiples.

[0011] As a further improvement of the technical solution of the present invention, the rotating polyhedron prism is circular, and is composed of N first reflecting surfaces, each of which is set at an angle of 45° to the horizontal direction. The fixed polyhedron prism is composed of a second reflecting surface and a third reflecting surface, and the second reflecting surface is set at an angle of 45° to the horizontal direction and is rotated 90° in the horizontal direction with the first reflecting surface. The third reflecting surface is set vertically and is set at an angle of 45° to the light path reflected by the second reflecting surface. After the light is reflected by the rotating polyhedron prism, N synchronous scanning lights with a scanning angle of 360° / N are formed.

[0012] As a further improvement of the technical solution of the present invention, the rotating polygonal prism is formed into a circular shape by an array of N wedge-shaped prisms, and each face of the fixed polygonal prism is arranged corresponding to each wedge-shaped prism face of the rotating polygonal prism. The light is refracted by the rotating polygonal prism to form N synchronous scanning lights with a scanning angle of 360° / N.

[0013] A laser radar, comprising at least two laser emitters for emitting detection lasers, an optical path system as described above, a horizontal rotating structure, and a motor control module, wherein the optical path system is used to transform at least two point light sources into vertical scanning light emitted from the center of a circle in a circularly equally divided manner, the rotating polyhedron prism, the fixed polyhedron prism, and the laser emitter are all installed on the horizontal rotating structure, and the motor control module comprises a motor control module No. 1 and a motor control module No. 2, wherein the motor control module No. 1 drives the rotating polyhedron prism to rotate, and the motor control module No. 2 drives the horizontal rotating structure to move.

[0014] This laser radar includes N laser emitters, an optical path system, a horizontal rotation structure, and a motor control module. The lasers emitted by the N laser emitters emit vertical scanning light through the optical path system. When the refresh rate is 1 / N, the rotation speed can be reduced, and the scanning time of each horizontal angle can be increased, thereby increasing the vertical scanning time within the horizontal scanning angle, and increasing the vertical resolution by multiples, reducing the cost and calibration work of the laser radar, and improving the vertical resolution of the laser radar to meet the technical parameter requirements of the multi-line laser radar of the multi-channel transmitter. The horizontal rotation structure is driven to rotate through the motor control module, thereby driving the laser emitter and the rotating polyhedron prism to rotate synchronously, thereby realizing 360° three-dimensional scanning.

[0015] As a further improvement of the technical solution of the present invention, the laser emitters are arranged in a circularly equally divided manner.

[0016] As a further improvement of the technical solution of the present invention, both the No. 1 motor control module and the No. 2 motor control module are equipped with code disks for determining the emission angles of the laser in the horizontal and vertical directions.

[0017] As a further improvement of the technical solution of the present invention, it also includes receivers, the number of which is equal to that of the laser transmitters, and the receivers are installed in a housing at equal intervals.

[0018] As a further improvement of the technical solution of the present invention, it also includes a focusing unit, which is arranged before the receiver and focuses the reflected laser to the receiver.

[0019] As a further improvement of the technical solution of the present invention, the receiver is an APD or SIPM sensor.

[0020] As a further improvement of the technical solution of the present invention, it also includes a collimation unit, which is arranged between the laser emitter and the rotating polygonal prism, and is used to collimate the outgoing laser emitted by the laser emitter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings:

[0022] Figure 1 Schematic diagram of embodiment 2 of the optical path system of the present invention;

[0023] Figure 2 A top view of a laser radar including an optical path system embodiment 2 of the present invention;

[0024] Figure 3 It is a front view of a laser radar including an optical path system embodiment 2 of the present invention;

[0025] Figure 4 This is a schematic diagram of Embodiment 1 of the optical path system of the present invention;

[0026] Figure 5 A top view of the laser radar including the optical path system embodiment 1 of the present invention

[0027] Figure 6 It is a top view of the laser radar containing the optical path system embodiment 1 of the present invention. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Reference Figure 4, an optical path system, which includes N synchronous light sources in a circularly equally divided manner, a rotating polygonal prism 300, and a fixed polygonal prism 400. Light enters the rotating polygonal prism 300, and is reflected or refracted by the rotating polygonal prism 300 to form scanning light. The scanning light is reflected by the fixed polygonal prism 400 to form N vertical scanning lights that are synchronously emitted from the center of the circle to the outside. Figure 4 In Example 1, the rotating polyhedron prism 300 is circular, and is composed of a plurality of first reflection surfaces 310, each of which is arranged at an angle of 45° to the horizontal direction. The fixed polyhedron prism 400 is composed of a second reflection surface 410 and a third reflection surface 420, the second reflection surface 410 is arranged at an angle of 45° to the horizontal direction and is arranged 90° rotated from the first reflection surface 310 in the horizontal direction, and the third reflection surface 420 is arranged vertically and is arranged at an angle of 45° to the light path reflected by the second reflection surface 410. After the light is incident on the rotating first reflection surface 310, it is reflected to form a scanning light with a certain angle and in an upward direction, and is directed by the second reflection surface 410 to change the direction by 90° and to the third reflection surface 420, and a vertical scanning light is formed from the center of the circle outward.

[0033] Reference Figure 1 In Example 2, the rotating polygonal prism 300 includes N faces. The rotating polygonal prism 300 has a circular wedge-shaped prism that is evenly cut into 1 / N parts according to an angle and one of the parts is arrayed into a circular composition. Each face of the fixed polygonal prism 400 corresponds to each 1 / N wedge-shaped prism face of the rotating polygonal prism 300 at a fixed angle. When light enters the rotating polygonal prism 300, the emitted light forms a certain scanning angle and upward scanning light after passing through each 1 / N wedge-shaped prism face. The light is reflected by the fixed polygonal prism 400 to form a vertical scanning light emitted from the center of the circle to the outside, and the object to be measured is scanned, effectively improving the vertical resolution and refresh rate.

[0034] Reference Figure 2 and Figure 3 as well as Figure 5 and Figure 6A laser radar includes at least two laser emitters 100 for emitting detection lasers, an optical path system as described above, a horizontal rotating structure 200, and a motor control module 500. The optical path system is used to form vertical scanning light from at least two point light sources in a circularly equally divided manner from the center of the circle to the outside. The rotating polyhedron prism 300, the fixed polyhedron prism 400, and the laser emitter 100 are all installed on the horizontal rotating structure 200. The motor control module 500 includes a first motor control module 510 and a second motor control module 520. The first motor control module 510 drives the rotating polyhedron prism 300 to rotate so that the light source forms a scanning light in one direction, and then converts the scanning light in the direction into a vertical scanning light emitted from the center of the circle to the outside through the fixed polyhedron prism 400. The second motor control module 520 drives the horizontal rotating structure 200 to move. The first motor control module 510 is disposed below the rotating polygonal prism 300 , and the second motor control module 520 is disposed below the horizontal rotating structure 200 .

[0035] The optical path system is embedded in the horizontal rotating structure 200, which drives the vertical scanning light beams in N directions to rotate, thereby realizing continuous multi-point three-dimensional spatial scanning of environmental targets. By combining this optical path system with the horizontal rotating structure 200, the technical requirements of 0.1° horizontal resolution (360°), 0.1-0.2° vertical resolution (15° up and down) and 10 frame refresh frequency can be met.

[0036] In this embodiment, the laser emitters 100 are arranged in a circular manner. When the refresh rate remains unchanged, the rotation speed can be reduced, and the scanning time of each horizontal angle can be increased, thereby increasing the vertical scanning time within the horizontal scanning angle, and increasing the vertical resolution by multiples, which can effectively reduce the cost of the laser radar and improve the vertical resolution of the laser radar.

[0037] The first motor control module 510 and the second motor control module 520 are both equipped with a code disk 530 for determining the emission angle of the laser in the horizontal and vertical directions.

[0038] In one embodiment, it further includes receivers 600, the number of which is equal to that of the laser transmitters 100, and the receivers 600 are evenly spaced in a housing. In order to better receive the signal, a focusing unit is provided before the receiver 600, and the focusing unit focuses the reflected laser to the receiver 600. The receiver 600 is an APD or SIPM sensor. In this embodiment, eight receivers 600 are evenly spaced at equal distances on the inner side of the housing.

[0039] Furthermore, a collimating unit is provided between the laser emitter 100 and the rotating polygonal prism 300 , and the collimating unit is used to collimate the outgoing laser emitted by the laser emitter 100 .

[0040] This laser radar includes N (at least two) laser emitters 100, an optical path system, a horizontal rotating structure 200, and a motor control module. The lasers emitted by the N laser emitters 100 emit scanning light in the vertical direction after passing through the optical path system. When the refresh rate is 1 / N, the rotation speed can be reduced, and the scanning time of each horizontal angle can be increased, thereby increasing the scanning time in the vertical direction within the horizontal scanning angle, and increasing the resolution in the vertical direction by multiples, reducing the cost and calibration workload of the laser radar, and improving the vertical resolution of the laser radar to meet the technical requirements of a multi-line laser radar with a multi-channel transmitter. The horizontal rotating structure is driven to rotate through the motor control module, thereby driving the laser emitter, the rotating polyhedron prism and the fixed polyhedron prism to rotate synchronously, thereby realizing 360° three-dimensional scanning.

[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: N light sources, the light sources emit light synchronously in a circularly equally divided manner, and N ≥ 2; Rotating polyhedral prism; Fixed polyhedral prism; The light enters the rotating polyhedron prism, and forms a scanning light after being reflected or refracted by the rotating polyhedron prism. The scanning light is reflected by the fixed polyhedron prism to form N vertical scanning lights that are synchronously emitted from the center of the circle to the outside. The rotating polyhedron prism is circular, and the rotating polyhedron prism is composed of N first reflecting surfaces, each of which is set at an angle of 45° to the horizontal direction. The fixed polyhedron prism is composed of a second reflecting surface and a third reflecting surface, and the second reflecting surface is at an angle of 45° to the horizontal direction and is aligned with the first The reflecting surface is arranged to rotate 90° in the horizontal direction, the third reflecting surface is arranged vertically and at an angle of 45° with the light path reflected by the second reflecting surface, and the light is reflected by the rotating polygonal prism to form N synchronous scanning lights with a scanning angle of 360° / N. The rotating polygonal prism is formed into a circle by an array of N wedge-shaped prisms, and each surface of the fixed polygonal prism is arranged corresponding to each wedge-shaped prism surface of the rotating polygonal prism. The light is refracted by the rotating polygonal prism to form N synchronous scanning lights with a scanning angle of 360° / N.

2. A laser radar, characterized in that: include: N laser emitters for emitting detection lasers, wherein N ≥ 2; The optical path system according to claim 1, wherein the optical path system is used to transform the lasers emitted by N laser emitters into vertical scanning lights that are emitted from the center of the circle outward in a circularly equally divided manner; A horizontal rotating structure, on which the rotating polyhedral prism, the fixed polyhedral prism and the laser transmitter are all mounted; The motor control module comprises a first motor control module and a second motor control module. The first motor control module drives the rotating polyhedron prism to rotate, and the second motor control module drives the horizontal rotating structure to move.

3. The laser radar according to claim 2, characterized in that: The laser emitters are arranged in a circumferentially equally divided manner.

4. The laser radar according to claim 2, characterized in that: The first motor control module and the second motor control module are both equipped with code disks for determining the emission angles of the laser in the horizontal and vertical directions.

5. The laser radar according to claim 2, characterized in that: It also includes receivers, the number of which is equal to that of the laser transmitters, and the receivers are installed in a shell at equal intervals.

6. The laser radar according to claim 5, characterized in that: The device also includes a focusing unit, which is arranged before the receiver and focuses the reflected laser light onto the receiver.

7. The laser radar according to claim 6, characterized in that: The receiver is an APD or SIPM sensor.

8. The laser radar according to claim 2, characterized in that: It also includes a collimating unit, which is arranged between the laser emitter and the rotating polygonal prism, and is used for collimating the outgoing laser emitted by the laser emitter.

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