Panoramic scanning laser radar device and preparation method

Abstract

The invention discloses a panoramic scanning laser radar device and a preparation method, the panoramic scanning laser radar device comprises a mirror body and a base, and the mirror body is rotatably arranged on the base; a driver is arranged on the base and comprises arc-shaped electrostatic comb teeth, a spring and a connecting piece, the arc-shaped electrostatic comb teeth comprise first comb teeth and second comb teeth, the spring is connected with the second comb teeth, one end of the connecting piece is connected with the second comb teeth, and the other end of the connecting piece is connected with the mirror body; and the driver is used for driving the mirror body to rotate under the action of a given driving signal. According to the panoramic scanning laser radar device provided by the invention, 360-degree omnibearing scanning is realized through a micro polygon scanning technology, the number of laser radar units is effectively reduced, and simplification of a radar system architecture is facilitated.

Description

Technical Field

[0001] The present application relates to the field of laser radar technology, and in particular to a panoramic scanning laser radar device and a preparation method thereof. Background Art

[0002] Currently, the commonly used LiDAR systems in autonomous vehicles mainly include rotating LiDAR and solid-state LiDAR. Rotating LiDAR achieves a 360-degree horizontal field of view (FOV) through mechanical rotation, but it has mechanical moving parts, which makes the system complex, easy to damage, high cost, large size and high power consumption. Although it can provide all-round environmental perception, it is not conducive to the long-term reliable operation of the vehicle.

[0003] Solid-state LiDAR achieves environmental perception through electronic scanning, has no mechanical moving parts, and has the advantages of high reliability and miniaturization. However, the scanning range of most current solid-state LiDARs is limited, usually not exceeding 120 degrees, and it is difficult to cover a 360-degree field of view. This means that in order to achieve all-round perception, autonomous vehicles must install multiple LiDAR units, which not only increases the complexity and cost of the system, but also brings problems with alignment and calibration, affecting the overall performance and stability of the sensor system.

[0004] In addition, existing solid-state lidar systems often have problems with high power consumption and heat dissipation at high speeds and high resolutions, which limits their application in miniaturized and high-efficiency autonomous driving systems.

[0005] In summary, the existing technology mainly has the following shortcomings: 1. The rotating lidar system is complex, costly, large in size, high in power consumption, and easy to damage.

[0006] 2. The scanning range of the solid-state laser radar system is limited, making it difficult to achieve 360-degree all-round perception.

[0007] 3. To achieve all-round perception, multiple lidar units need to be installed, which increases system complexity and cost, and brings about alignment and calibration issues.

[0008] 4. High-speed and high-resolution solid-state lidar has high power consumption and difficulty in heat dissipation, which limits its application. Summary of the invention

[0009] The present application provides a panoramic scanning laser radar device and a preparation method. The advantage is that the panoramic scanning laser radar device provided achieves 360-degree all-round scanning through micro-polygon scanning technology, effectively reduces the number of laser radar units, and is conducive to simplifying the radar system architecture.

[0010] The technical solution of this application is as follows: On the one hand, the present application provides a panoramic scanning laser radar device, comprising a mirror body and a base, wherein the mirror body is rotatably arranged on the base; The base is provided with a driver, the driver includes arc-shaped electrostatic comb teeth, a spring and a connecting piece, the arc-shaped electrostatic comb teeth include first comb teeth and second comb teeth, the spring is connected to the second comb teeth, one end of the connecting piece is connected to the second comb teeth, and the other end is connected to the mirror body; The driver is used to drive the mirror body to rotate under the action of a given driving signal.

[0011] Furthermore, the mirror body is a polyhedron structure in the shape of a pyramid.

[0012] Furthermore, a first anchor and a second anchor are provided on the base, one end of the first comb tooth is connected to the first anchor, and one end of the spring is connected to the second anchor.

[0013] Furthermore, the spring is a V-shaped cantilever beam configuration, one end of which is connected to the second anchoring member, and the other end is connected to the connecting member, and the spring is deformed when the mirror body rotates.

[0014] Furthermore, the driver includes four groups of arc-shaped electrostatic comb teeth, springs and connectors, which are arranged at equiangular intervals on the circumferential positions of the mirror body.

[0015] Furthermore, a rotating mirror base is provided at the bottom of the mirror body, and a connecting piece is connected to the rotating mirror base, and the connecting piece is tangent to the rotating mirror base.

[0016] In another aspect, the present application provides a method for preparing a panoramic scanning laser radar device, which is used to prepare the panoramic scanning laser radar device as described above, comprising the following steps: S1: On the silicon wafer on the first insulating layer, a mirror body is prepared by photolithography and etching; S11: The silicon wafer on the first insulating layer is etched on the support layer by photolithography and wet etching to obtain a pyramid-shaped polygonal surface of the mirror body; S12: Photolithography and etching are performed on the front side of the silicon wafer on the first insulating layer to obtain the rotating mirror base of the mirror body S2: On the silicon wafer on the second insulating layer, a base with a driver is prepared by photolithography and etching; S21: performing photolithography and deep cavity etching on the front side of the silicon wafer on the second insulating layer to obtain a driver structure on the base; S22: performing photolithography and deep cavity etching on the back side of the silicon wafer on the second insulating layer to remove excess materials to obtain a base; S3: Bonding the mirror body and the base.

[0017] On the other hand, the present application provides a laser radar, including the panoramic scanning laser radar device as described above.

[0018] In summary, the beneficial effects of this application are: 1. Omnidirectional scanning capability: Through micro-polygon design based on MEMS technology, the present invention realizes omnidirectional beam scanning with a horizontal field of view (FOV) of 360 degrees, overcoming the problem of limited scanning range of traditional solid-state LiDAR systems and avoiding the complexity and cost of installing multiple LiDAR units to achieve omnidirectional perception.

[0019] 2. System simplification and cost reduction: Traditional multi-lidar configuration increases the complexity and cost of autonomous vehicle sensor systems. The present invention achieves omnidirectional scanning through a single micro-polygonal lidar, simplifies the system architecture, and significantly reduces installation and maintenance costs.

[0020] 3. High speed and high resolution: The present invention uses radial comb drives to achieve high-speed rotation of micropolygons, thereby achieving high-speed beam scanning. At the same time, the design of micropolygons makes beam scanning more stable at high resolution, effectively improving the real-time and accuracy of environmental perception.

[0021] 4. Miniaturization and reliability: The present invention miniaturizes the polygonal design to the semiconductor device level, making the LiDAR system small in size and light in weight, suitable for installation on autonomous driving vehicles with limited space. The application of MEMS technology eliminates mechanical moving parts, significantly improving the reliability and service life of the system.

[0022] 5. Mass production and consistency: The present invention adopts a two-piece SOI wafer manufacturing process, which enables micropolygons to be mass-produced at the wafer level. This not only reduces manufacturing costs, but also ensures product consistency and quality control, making the popularization of high-performance lidar systems possible.

[0023] 6. Energy consumption optimization and heat dissipation improvement: Compared with the traditional mechanical rotating laser radar, the micro-polygon laser radar system of the present invention realizes efficient energy utilization through MEMS technology, reducing the power consumption of the system. At the same time, the miniaturized design also helps to improve the heat dissipation performance, further improving the reliability and stability of the system.

[0024] 7. Improved optical performance: The micro-polygonal single-crystal silicon mechanical support structure and precise manufacturing process ensure excellent optical performance during beam scanning, reduce alignment difficulties and unstable optical performance, and improve the accuracy of environmental perception.

[0025] Through the above-mentioned beneficial effects, the present invention significantly improves the application performance of the lidar system in autonomous driving vehicles, provides an efficient, reliable and economical all-round environmental perception solution, and is conducive to promoting the development and popularization of autonomous driving technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a mirror body with a polygonal structure in this application; Figure 2 It is a schematic diagram of the structural principle of the panoramic scanning laser radar device in this application; Figure 3 It is a schematic diagram of the preparation process of the panoramic scanning laser radar device in this application. DETAILED DESCRIPTION

[0027] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0028] A specific embodiment of the present application provides a panoramic scanning laser radar device, including a mirror body and a base, wherein the mirror body is rotatably arranged on the base; The base is provided with a driver, the driver includes arc-shaped electrostatic comb teeth, a spring and a connecting piece, the arc-shaped electrostatic comb teeth include first comb teeth and second comb teeth, the spring is connected to the second comb teeth, one end of the connecting piece is connected to the second comb teeth, and the other end is connected to the mirror body; The driver is used to drive the mirror body to rotate under the action of a given driving signal.

[0029] The mirror body is a pyramid-shaped polyhedron structure, and its slope angle is naturally determined by the single crystal silicon crystal structure.

[0030] The base is provided with a first anchor and a second anchor, one end of the first comb tooth is connected to the first anchor, and one end of the spring is connected to the second anchor.

[0031] The spring is a V-shaped cantilever beam configuration, one end of which is connected to the second anchoring member, and the other end of which is connected to the connecting member. The spring is deformed when the mirror body rotates. The spring of the V-shaped cantilever beam configuration can provide sufficient driving length and a good lateral movement suppression ratio. After a bias voltage is applied between the two groups of arc-shaped comb teeth, a relative displacement is generated between the arc-shaped comb teeth, driving the spring cantilever beam to produce deformation in the arc direction.

[0032] The driver comprises four groups of arc-shaped electrostatic comb teeth, springs and connecting parts, which are arranged at equiangular intervals at circumferential positions of the mirror body.

[0033] A rotating mirror base is provided at the bottom of the mirror body, and a connecting piece is connected to the rotating mirror base, and the connecting piece is tangent to the rotating mirror base.

[0034] Another specific embodiment of the present application provides a method for preparing a panoramic scanning laser radar device, which is used to prepare the panoramic scanning laser radar device as described above, and is prepared by two silicon-on-insulator (SOI) wafers, including the following steps: SOI wafer preparation: Two high-quality SOI wafers are selected, the first one is used to build the pyramidal surface of the micropolygon, and the second one is used to build the radial comb drive.

[0035] S1: On the first insulating layer silicon wafer, the mirror body is prepared by photolithography and etching; after the initial insulating layer silicon wafer (SOI) wafer is subjected to mask and photolithography process, it can be etched by TMAH or KOH to produce a slope side with an angle of 54.74 degrees.

[0036] S11: The silicon wafer on the first insulating layer is subjected to photolithography and wet etching to obtain a pyramid-shaped polygonal surface of the mirror body on the support layer (handle layer); S12: Photolithography and etching are performed on the front side of the silicon wafer on the first insulating layer to obtain a rotating mirror base of the mirror body; specifically, a front side etching technology is used to construct a rotating mirror base under the micro-polygon to provide mechanical support S2: On the silicon wafer on the second insulating layer, a base with a driver is prepared by photolithography and etching; the high aspect ratio spring and comb driver mechanical structure are completed by anisotropic dry deep cavity etching (DRIE) after photolithography. After that, after the reverse alignment and photolithography are completed, the process steps of releasing the through hole and mechanical structure are completed by large-area deep cavity etching.

[0037] S21: performing photolithography and deep cavity etching on the front side of the silicon wafer on the second insulating layer to obtain a driver structure on the base; specifically, constructing a radial comb driver structure on the device layer of the second SOI wafer by photolithography and dry etching techniques.

[0038] S22: performing photolithography and deep cavity etching on the back side of the silicon wafer on the second insulating layer to remove excess materials to obtain a base; S3: Bond the mirror body and the base, and bond the processed first and second SOI wafers to ensure that the micro-polygon and radial comb drive are aligned and tightly connected. After the two wafers are aligned and bonded at high temperature, mechanical dicing is used to obtain a double-layer complete micro-optical mechanical device with the lower layer being the drive, spring, anchoring structure, and the upper layer being the cone-shaped rotating mirror body.

[0039] Release and assembly: Through the release process, the micropolygons are ensured to have rotational freedom and are mounted on the traction mechanical actuator structure.

[0040] The mechanical support of the micropolygon is made of single crystal silicon and is mounted on top of the drive structure. The micropolygon is rotated along the central axis by 4 pairs of radial comb drives.

[0041] Another specific embodiment of the present application provides a laser radar, including the panoramic scanning laser radar device as described above.

[0042] The above is only a preferred implementation of the present application. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present application, and these all fall within the scope of protection of the present application.

Claims

1. A panoramic scanning laser radar device, characterized in that: It comprises a mirror body and a base, wherein the mirror body is rotatably arranged on the base; The base is provided with a driver, the driver includes arc-shaped electrostatic comb teeth, a spring and a connecting piece, the arc-shaped electrostatic comb teeth include first comb teeth and second comb teeth, the spring is connected to the second comb teeth, one end of the connecting piece is connected to the second comb teeth, and the other end is connected to the mirror body; The driver is used to drive the mirror body to rotate under the action of a given driving signal.

2. The panoramic scanning laser radar device according to claim 1, characterized in that: The mirror body is a pyramid-shaped polyhedron structure.

3. The panoramic scanning laser radar device according to claim 2, characterized in that: The base is provided with a first anchor and a second anchor, one end of the first comb tooth is connected to the first anchor, and one end of the spring is connected to the second anchor.

4. The panoramic scanning laser radar device according to claim 3, characterized in that: The spring is in a V-shaped cantilever beam configuration, one end of which is connected to the second anchoring member, and the other end of which is connected to the connecting member. The spring is deformed when the mirror body rotates.

5. The panoramic scanning laser radar device according to claim 4, characterized in that: The driver comprises four groups of arc-shaped electrostatic comb teeth, springs and connecting parts, which are arranged at equiangular intervals at circumferential positions of the mirror body.

6. The panoramic scanning laser radar device according to claim 5, characterized in that: A rotating mirror base is provided at the bottom of the mirror body, and a connecting piece is connected to the rotating mirror base, and the connecting piece is tangent to the rotating mirror base.

7. A method for preparing a panoramic scanning laser radar device, used for preparing the panoramic scanning laser radar device as claimed in claim 6, characterized in that: The following steps are involved: S1: On the silicon wafer on the first insulating layer, a mirror body is prepared by photolithography and etching; S11: The silicon wafer on the first insulating layer is etched on the support layer by photolithography and wet etching to obtain a pyramid-shaped polygonal surface of the mirror body; S12: Photolithography and etching are performed on the front side of the silicon wafer on the first insulating layer to obtain the rotating mirror base of the mirror body S2: On the silicon wafer on the second insulating layer, a base with a driver is prepared by photolithography and etching; S21: performing photolithography and deep cavity etching on the front side of the silicon wafer on the second insulating layer to obtain a driver structure on the base; S22: performing photolithography and deep cavity etching on the back side of the silicon wafer on the second insulating layer to remove excess materials to obtain a base; S3: Bonding the mirror body and the base.

8. A laser radar, characterized in that: It comprises a panoramic scanning laser radar device as described in any one of claims 1 to 6.

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