Multi-line laser radar based on super lens

Abstract

The utility model relates to the field of sweeping robots, in particular to a multi-line laser radar based on a super lens, which comprises a rotating table, a transmitting end and a receiving end, the rotating table can rotate by 360 degrees; the transmitting end comprises a pulse laser and a transmitting super lens; the receiving end comprises a receiving super lens and a detector; wherein the pulse laser is used for emitting a laser beam, the transmitting super lens is used for collimating the laser beam and dividing the laser beam into a plurality of sub-beams, the receiving super lens is used for collecting the laser beam reflected from a target object, and the detector is used for converting the laser beam into an electric signal. Compared with a current mainstream triangulation ranging single-line laser radar, full-scale high-precision modeling and near large-angle obstacle avoidance of the multi-line laser radar are met by using the pulse laser; and the transmitting and receiving ends adopt a super-lens optical scheme, so that the overall size and weight of the multi-line laser radar are greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of sweeping robots, in particular to a multi-line laser radar based on a super lens. Background Art

[0002] A superlens is a highly integrated, two-dimensional planar lens based on a micro-nano optical structure. Unlike traditional lenses, which often require a combination of multiple discrete lenses, a single superlens can replace heavy traditional lenses, boasting the advantages of thinness, light weight, low cost, and high integration. Through optimized design, a superlens can manipulate the phase, amplitude, polarization, and spectrum of light, and is widely used in fields such as display, imaging, communications, and sensing. For example, STMicroelectronics has integrated a superlens from Metalenz into its TOF distance sensor chip. Combining this with LiDAR applications can fully leverage the compactness and miniaturization of superlenses. Currently, LiDAR is a crucial tool for modeling and obstacle avoidance in sweeping robots, and high-performance obstacle avoidance often relies on a large field of view.

[0003] However, mainstream single-line LiDARs cannot achieve large vertical field-of-view obstacle avoidance. If traditional vehicle-mounted scanning multi-line LiDARs are installed on sweeping robots, they will have no advantages in terms of size, power consumption, and cost. Therefore, the industry has proposed a demand for compact multi-line LiDARs that can simultaneously achieve high-precision modeling of the full range of sweeping robots and large-angle obstacle avoidance at close range. Based on this, this application proposes a multi-line LiDAR based on a super lens that can simultaneously take into account large-angle obstacle avoidance at close range and high-precision modeling of the full range. Utility Model Content

[0004] To solve the problem in the current field of sweeping robots that multi-line laser radar cannot meet the requirements of compact structure and simultaneous consideration of close-range large-angle obstacle avoidance and full-range high-distance accuracy modeling.

[0005] The utility model provides a multi-line laser radar based on a metalens, comprising a rotating platform and a transmitting end and a receiving end arranged on the rotating platform; the rotating platform can rotate 360 degrees; the transmitting end comprises a pulsed laser and a transmitting metalens; the receiving end comprises a receiving metalens and a detector; wherein, the pulsed laser is used to emit a laser beam, the transmitting metalens is used to collimate the laser beam and divide the laser beam into multiple sub-beams, the receiving metalens is used to collect the laser beam reflected from the target object, and the detector is used to convert the laser beam into an electrical signal.

[0006] Preferably, the detector is a single photon avalanche diode detector array chip.

[0007] Preferably, the detector is composed of discrete single photon avalanche diodes.

[0008] Preferably, a multi-line laser radar based on a metalens also includes a beam shaping metalens, and the beam shaping metalens is located between the detector and the receiving metalens.

[0009] Preferably, the vertical field of view of the multi-line laser radar based on the metalens is The degree is 50°~120°.

[0010] Preferably, the receiving end further includes a signal processing circuit and a control unit, the signal processing circuit is used to process the electrical signal input by the detector, and the control unit is used to transmit the processed electrical signal and control the timing of the transmitting end and the receiving end.

[0011] The beneficial effects of this utility model are reflected in the fact that, compared to the current mainstream single-line LiDAR using triangulation ranging, the use of pulsed lasers enables multi-line LiDAR to achieve high-precision modeling over the entire range and near-range, wide-angle obstacle avoidance. Furthermore, the use of a superlens optical solution on both the transceiver and transmitter significantly reduces the size and weight of the multi-line LiDAR. This solves the current problem in the field of sweeping robots, where multi-line LiDAR cannot meet the requirements of compact structure, near-range, wide-angle obstacle avoidance, and full-range, high-precision modeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural schematic diagram of a multi-line laser radar based on a superlens provided by the utility model.

[0013] Figure 2 This is a schematic diagram of the full-range modeling and close-range large-angle obstacle avoidance of a multi-line laser radar based on a superlens provided by the utility model.

[0014] Figure 3 Schematic diagram of the structure of the detection end composed of a single-photon avalanche diode detector array chip and a receiving super lens.

[0015] Figure 4 Schematic diagram of the structure of the detection end composed of multiple discrete single-photon avalanche diodes combined into a detector array and a receiving super lens.

[0016] In the figure: 1-multi-line laser radar based on superlens; 2-rotating stage; 3-pulsed laser; 31-laser beam; 4-emitting superlens; 5-receiving superlens; 6-detector; 61-single-photon avalanche diode; 62-single-photon avalanche diode detector array chip; 7-beam shaping superlens; 8-target object; 9-imaging focal plane; 10-sweeping robot. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0018] In the description of this utility model, it should be understood that "-" and "~" represent a range between two values, and the range is inclusive. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0019] Reference Figure 1-Figure 4 A multi-line laser radar 1 based on a metalens includes a rotating platform 2 and a transmitting end and a receiving end arranged on the rotating platform 2; the rotating platform 2 can rotate 360 degrees; the transmitting end includes a pulse laser 3 and a transmitting metalens 4; the receiving end includes a receiving metalens 5 and a detector 6; wherein, the pulse laser 3 is used to emit a laser beam 31, the transmitting metalens 4 is used to collimate the laser beam 31 and divide the laser beam 31 into multiple sub-beams, the receiving metalens 5 is used to collect the laser beam 31 reflected from the target object 8, and the detector 6 is used to convert the laser beam 31 into an electrical signal.

[0020] Compared to the current mainstream single-line LiDAR using triangulation, the use of pulsed lasers 3 enables multi-line LiDAR to achieve high-precision modeling across the entire range and near-field wide-angle obstacle avoidance. Furthermore, the use of a superlens optical solution on both the transmitter and receiver significantly reduces the overall size and weight of the multi-line LiDAR. This addresses the current challenge in the robotic vacuum cleaner market, where multi-line LiDAR cannot meet the requirements for compact structure, near-field wide-angle obstacle avoidance, and high-precision modeling across the entire range.

[0021] like Figure 1 As shown in FIG, the laser radar transmitting end of the present invention is composed of a pulsed laser 3 and a transmitting metalens 4. The transmitting metalens 4 realizes the collimation of the laser beam 31 and divides the collimated beam into multiple sub-beams. This patent proposes to replace the traditional transmitting optical system with only one transmitting metalens 4. To achieve the same function, the traditional transmitting optical system often needs to be composed of a separate collimating lens and a one-dimensional diffraction optical element. As an example, Figure 2 As shown, the laser beam 31 is divided into three sub-beams (B1, B2 and B3). The divergence angle of B2 illuminates object 1 (O1) at a distance of Lf, and B3 illuminates object 2 (O2) and object 3 (O3) at a close distance of Ln respectively.

[0022] In some embodiments, the detector 6 is a single photon avalanche diode detector array chip 62 .

[0023] By using a single-photon avalanche diode detector array chip 62, the monolithic receiving superlens 5 can be closely attached to the chip surface to achieve imaging detection, making the structure of the multi-line laser radar more compact, which is different from the traditional receiving lens that often requires a relatively long back focal length.

[0024] In some embodiments, the detector 6 is composed of discrete single photon avalanche diodes 61 .

[0025] By combining multiple discrete single-photon avalanche diodes 61, signals can be received from different angles or regions simultaneously, thereby achieving spatial parallel processing, which helps to improve the resolution and data acquisition speed of the lidar system.

[0026] The lidar of this invention uses direct time-of-flight (dTOF) ranging. The lidar emits brief light pulses, which are reflected from a target object 8 and received by a detector 6. The distance to the target object 8 is calculated by measuring the time difference between the transmitted and reflected light pulses. This full-range ranging accuracy is significantly higher than that of traditional, inexpensive triangulation-based lidars. The entire multi-line dTOF lidar is placed on a rotating stage 2, enabling 360° scanning detection. The number of sub-beams on the transmitting end matches the number of channels on the detecting end.

[0027] Furthermore, a multi-line laser radar 1 based on a superlens also includes a beam shaping superlens 7, which is located between the detector 6 and the receiving superlens 5.

[0028] A detector array is formed by combining multiple discrete single-photon avalanche diodes 61. Because the pixel pitch of this type of detector array is often higher than the pixel pitch of the single-photon avalanche diode detector array chip 62, a beam-shaping metalens 7 is placed after the imaging focal plane 9 of the receiving metalens 5 to collimate the imaged sub-beams and expand the sub-beam spacing to match the pixel spacing of the discrete detector array. Therefore, the beam-shaping metalens 7 is used to achieve sub-beam collimation and spacing conversion.

[0029] like Figure 4 As shown, a compact receiving metalens 5 collimates three sub-beams spaced d1 (d1 is 1 mm) in the imaging focal plane 9 and projects them onto a detection array spaced d2 (d2 is 5 mm). Through design optimization, the receiving metalens 5 and the beam-shaping metalens 7 can also be combined into a single device.

[0030] In some embodiments, the vertical field of view of the multi-line laser radar 1 based on the metalens is The degree is 50°~120°.

[0031] The larger vertical field of view combined with a 360° horizontal field of view means a wider range of angles can be scanned simultaneously, thereby acquiring more data points in the same amount of time. In smart home applications, for example, the robot vacuum 10 can optimize its cleaning path or avoid obstacles based on the room layout and scanning range.

[0032] In some embodiments, the receiving end further includes a signal processing circuit and a control unit. The signal processing circuit is used to process the electrical signal input by the detector, and the control unit is used to transmit the processed electrical signal and control the timing of the transmitting end and the receiving end.

[0033] How it works:

[0034] like Figure 2 As shown, a multi-line laser radar 1 based on a super lens is mounted on top of a sweeping robot 10. Figure 2 Detector 6 used for near-field obstacle avoidance does not require a strong reflected laser signal to detect nearby overhead and ground obstacles separately. A top target O2 refers to an object at a height H2 above the ground, such as the bottom of a sofa; a ground target O3 refers to an object at a height H3 above the ground, such as low objects like socks and slippers. The staggered field of view of B2 and B3 is wider than that covered by a traditional single-line lidar. B2 can detect objects on top of the robot vacuum 10, such as a sofa. If the height H1 of the robot vacuum 10 is higher than the distance H2 from the ground, the robot vacuum 10 will determine that the sofa is an obstacle and will not enter the bottom of the sofa. A multi-line lidar based on a superlens can replace the line laser sensors currently integrated into robot vacuums for obstacle avoidance. This has the advantage of reducing the number of integrated sensors in the robot vacuum, reducing costs and enabling a smaller robot. Furthermore, the performance consistency of the modeling and obstacle avoidance sensors can be guaranteed during mass production. This simplifies sensor calibration and assembly steps during production, improving production efficiency.

[0035] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-line laser radar based on a superlens, characterized by: It includes a rotating table and a transmitting end and a receiving end arranged on the rotating table; the rotating table can rotate 360°; the transmitting end includes a pulse laser and a transmitting super lens; the receiving end includes a receiving super lens and a detector; wherein, the pulse laser is used to emit a laser beam, the transmitting super lens is used to collimate the laser beam and divide the laser beam into multiple sub-beams, the receiving super lens is used to collect the laser beam reflected from the target object, and the detector is used to convert the laser beam into an electrical signal.

2. The multi-line laser radar based on a superlens according to claim 1, characterized in that: The detector is a single photon avalanche diode detector array chip.

3. The multi-line laser radar based on a superlens according to claim 1, characterized in that: The detector is composed of discrete single-photon avalanche diodes.

4. The multi-line laser radar based on a superlens according to claim 3, characterized in that: Also included is a beam shaping metalens positioned between the detector and the receiving metalens.

5. The multi-line laser radar based on a superlens according to claim 1, characterized in that: Vertical field of view of the multi-line laser radar based on the superlens The degree is 50°~120°.

6. The multi-line laser radar based on a superlens according to claim 1, characterized in that: The receiving end also includes a signal processing circuit and a control unit. The signal processing circuit is used to process the electrical signal input by the detector, and the control unit is used to transmit the processed electrical signal and control the timing of the transmitting end and the receiving end.

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