Laser radar compensation alignment device and laser radar
By designing a compensation alignment device in lidar and adjusting the light direction using beam displacement elements, the problems of lidar optical path inclination and centrifugation are solved, the detection performance is improved and the assembly process is simplified.
Patent Information
- Application Number
- CN202420602708.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-26
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-03-26
AI Technical Summary
Due to manufacturing and assembly errors, the receiving modules of existing lidars lead to tilt and centrifugation of optical paths, which affects detection performance. The existing solutions are complex and have a long installation and adjustment time.
A lidar compensation alignment device is designed, by sequentially providing a receiving optical element, a first beam displacement element and a second beam displacement element from the object side to the image side, and refracting and deflecting the initial beam by using these beam displacement elements to adjust the main optical axis direction of the light to make it closer to the target object direction.
Through this device, the assembly tolerance required for lidar to receive focus or beam splitting elements is reduced, and the detection performance of lidar is improved. The device is simple and easy to install, with moderate sensitivity, high accuracy and good stability.
Smart Images
Figure CN222599826U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optical design, and in particular to a laser radar compensation alignment device and a laser radar. Background Art
[0002] As a high-precision and high-reliability distance measurement device, LiDAR has been widely used in autonomous driving, intelligent manufacturing, robotics and other fields. The core components of LiDAR include transmitting module, scanning and receiving modules, among which the receiving module is an important component that converts the optical signal reflected by the emitted laser into a digital signal. The receiving module obtains the distance or moving speed of the target through information such as the round-trip time of photons in the medium between the transmitting end and the target object. However, the optical system in the receiving module usually forms an inclination and centrifugation of the optical path due to errors such as manufacturing tolerance and assembly tolerance, resulting in deviations in the energy received by the detector, affecting the detection performance of the LiDAR.
[0003] Existing LiDARs often reduce this deviation by tightening tolerances, but this can cause processing difficulties; or by adjusting the alignment system to give the assembly equipment multiple degrees of freedom, but this adjustment method is too complicated and takes too long; or usually a reflector is used in the receiving optical path to fold the light, and the angle deviation between the reflecting surface and the optical axis is large, resulting in greater assembly sensitivity. Utility Model Content
[0004] The purpose of the utility model is to provide a laser radar compensation alignment device and a laser radar, which, by setting a plurality of beam displacement elements with a simple structure and easy installation, have moderate sensitivity, high precision and good stability, and can greatly reduce the assembly tolerance required to be complied with by the receiving focusing or beam splitting elements of the laser radar, thereby improving the detection performance of the laser radar.
[0005] The embodiment of the utility model is achieved as follows:
[0006] In one aspect of the utility model, a laser radar compensation and alignment device is provided, comprising a receiving optical element, a first beam displacement element and a second beam displacement element which are arranged in sequence from the object side to the image side, the receiving optical element being used to receive an initial beam reflected by the laser radar to the target and carrying target information, the initial beam being refracted by the first beam displacement element to be a first output light beam; the first output light beam being refracted by the second beam displacement element to be a second output light beam, the angle between the main optical axis of the second output light beam and the direction of the target object being smaller than the angle between the main optical axis of the initial beam and the direction of the target object.
[0007] Optionally, the first beam displacement element is an optical plate, and the second beam displacement element is a wedge prism.
[0008] Optionally, the first beam displacement element is a wedge prism, and the second beam displacement element is an optical flat plate.
[0009] Optionally, an anti-reflection film is provided on the incident surface and / or the exit surface of the optical flat plate.
[0010] Optionally, the laser radar compensation and alignment device also includes a detector, which is arranged on the light-emitting side of the second beam displacement element, and the second output light emitted by the second beam displacement element is received by the detector.
[0011] Optionally, the laser radar compensation and alignment device also includes a spectroscopic element, which is arranged between the second beam displacement element and the detector. The second output light emitted by the second beam displacement element is divided into multiple sub-beams emitted in multiple directions by the spectroscopic element, and the multiple sub-beams are received by the detector.
[0012] Optionally, the detector is a plurality of evenly distributed sub-detectors, the number of the plurality of sub-detectors corresponds one-to-one to the number of the plurality of sub-light beams, and the sub-light beams are incident on the sub-detectors one-to-one.
[0013] Optionally, the detector is an area array detector, and the multiple sub-light beams are correspondingly incident on the detection surface of the area array detector.
[0014] Optionally, the optical axis center of the beam splitting element is aligned with the optical axis center of the receiving optical element after passing through the first beam displacement element and the second beam displacement element.
[0015] Another aspect of the present invention provides a laser radar, which includes the above-mentioned laser radar compensation and alignment device.
[0016] The beneficial effects of the utility model include:
[0017] The present application provides a laser radar compensation alignment device, comprising a receiving optical element, a first beam displacement element and a second beam displacement element arranged in sequence from the object side to the image side, the receiving optical element is used to receive the initial beam emitted by the laser radar to the target and reflected by the target information, the initial beam is refracted by the first beam displacement element and emitted as a first emitted light; the first emitted light is refracted by the second beam displacement element and emitted as a second emitted light, the angle between the main optical axis of the second emitted light and the direction of the target is smaller than the angle between the main optical axis of the initial beam and the direction of the target. The laser radar compensation alignment device obtained by the above design, by setting a plurality of beam displacement elements with simple structure and easy installation, has moderate sensitivity, high precision and good stability, and can greatly reduce the assembly tolerance required to be observed by the receiving focusing or beam splitting elements of the laser radar, thereby improving the detection performance of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0019] Figure 1 A schematic diagram of the optical path of the laser radar compensation alignment device provided in this application;
[0020] Figure 2 A diagram of the refraction principle of the optical plate provided for this application;
[0021] Figure 3 A diagram of the refraction principle of the wedge prism provided for this application;
[0022] Figure 4 The angle and displacement relationship curve of the wedge prism provided in this application;
[0023] Figure 5 The angle and displacement relationship curve of the optical plate provided in this application;
[0024] Figure 6 Schematic diagram of the optical path of an existing laser radar without a compensation alignment device.
[0025] Icons: 100 - laser radar compensation and alignment device; 110 - receiving optical element; 111 - initial light beam; 120 - first light beam displacement element; 121 - first outgoing light beam; 130 - second light beam displacement element; 131 - second outgoing light beam; 140 - spectrometer element; 141 - sub-beam; 150 - detector; 151 - sub-detector; 152 - array detector. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.
[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.
[0029] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does 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 cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0030] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0031] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0032] Please refer to Figure 1 The present embodiment provides a laser radar compensation and alignment device 100, comprising a receiving optical element 110, a first beam displacement element 120 and a second beam displacement element 130 arranged in sequence from the object side to the image side, the receiving optical element 110 is used to receive an initial beam 111 emitted by the laser radar to the target and reflected with target information, the initial beam 111 is refracted by the first beam displacement element 120 to be a first emitted light 121; the first emitted light 121 is refracted by the second beam displacement element 130 to be a second emitted light 131, and the angle between the main optical axis of the second emitted light 131 and the target direction is smaller than the angle between the main optical axis of the initial beam 111 and the target direction.
[0033] Specifically, the present application discloses a laser radar compensation alignment device 100, which includes a receiving optical element 110, which is used to receive an initial light beam 111 emitted by the laser radar to a target object and returned; it also includes a first light beam displacement element 120 and a second light beam displacement element 130, which can translate and tilt the light; the receiving optical element 110, the first light beam displacement element 120 and the second light beam displacement element 130 are arranged in sequence from the object side to the image side.
[0034] The initial light beam 111 emitted by the laser radar to the target on the object side and returned is received by the receiving optical element 110, and is incident on the incident surface of the first beam displacement element 120, and is deflected by the first beam displacement element 120, and emits a first outgoing light 121 through the outgoing surface of the first beam displacement element 120; the first outgoing light 121 is incident on the incident surface of the second beam displacement element 130 and is deflected by the second beam displacement element 130, and is emitted through the outgoing surface of the second beam displacement element 130 and imaged. The angle between the main optical axis of the second outgoing light 131 emitted by the initial light beam 111 after two deflections by the first beam displacement element 120 and the second beam displacement element 130 and the direction of the target is smaller than the angle between the main optical axis of the initial light and the direction of the target.
[0035] Since the first beam displacement element 120 of the laser radar compensation and alignment device 100 of the present application has a certain angle with the optical axis, it can effectively avoid the generation of FP type reflected stray light, thereby improving the robustness of the laser radar compensation and alignment device 100.
[0036] It should be noted that, in the embodiment of the present application, first, the laser radar compensation alignment device 100 further includes a beam splitter 140, which is disposed on a side of the second beam displacement element 130 close to the object side. The second outgoing light 131 emitted by the second beam displacement element 130 is divided into a plurality of sub-beams 141 by the beam splitter 140, and the plurality of sub-beams 141 are emitted by the beam splitter 140 and imaged. The center of the optical axis where the beam splitter 140 is located is set as the theoretical optical axis, and the angle and distance between the emitted second outgoing light 131 and the target direction are smaller than the angle and distance between the initial light and the target direction, that is, the light beam emitted by the beam splitter 140 is closer to the theoretical optical axis. Among them, the optical axis center of the beam splitter 140 and the optical axis center of the receiving optical element 110 are aligned after passing through the first beam displacement element 120 and the second beam displacement element 130.
[0037] Second, the laser radar compensation and alignment device 100 also includes a detector 150, which is arranged on the side of the second beam displacement element 130 away from the object side, and the spectroscopic element 140 is located between the second beam displacement element 130 and the detector 150; the second output light 131 emitted by the second beam displacement element 130 is split by the spectroscopic element 140 and then received by the detector 150, and the deflected light beam can reach the surface of the detector 150 through the guidance of the spectroscopic element 140.
[0038] Third, the laser radar compensation alignment device 100 provided in the present application uses a beam displacement element with a relatively simple structure and convenient assembly. In the assembly process of the laser radar compensation alignment device 100, the beam splitter 140 is first assembled so that the optical axis center of the beam splitter 140 is aligned with the optical axis center of the receiving optical element 110 after passing through the first beam displacement element 120 and the second beam displacement element 130, and then the first beam displacement element 120 and the second beam displacement element 130 are adjusted to tilt or rotate to the optimal position, and then the position of the first beam displacement element 120 and the second beam displacement element 130 is cured using ultraviolet curing glue. During the collimation and curing stage, the collimation can be confirmed in combination with an optical power meter or an autocollimator, so that the second outgoing light 131 is emitted from the beam splitter 140 near the center of the detector 150, and at this time, the coupling efficiency, that is, the outgoing power, reaches the optimal. Among them, the optimal position of the first beam displacement element 120 and the second beam displacement element 130 is the size and position of the light spot on the surface of the detector 150 without tolerance. The operator can determine whether it is the best position according to the shape of the light spot on the detector 150. Curing is performed by ultraviolet curing glue, which has low sensitivity and can absorb the error caused by the displacement before and after the glue is cured. At the same time, it also reduces the time required for the assembly process and simplifies the assembly process.
[0039] The present application provides a laser radar compensation and alignment device 100, comprising a receiving optical element 110, a first beam displacement element 120 and a second beam displacement element 130 arranged in sequence from the object side to the image side, the receiving optical element 110 is used to receive the initial beam 111 emitted by the laser radar to the target and reflected with the target information, the initial beam 111 is refracted by the first beam displacement element 120 and emitted as a first emitted light 121; the first emitted light 121 is refracted by the second beam displacement element 130 and emitted as a second emitted light 131, the angle between the main optical axis direction of the second emitted light 131 and the target direction is smaller than the angle between the main optical axis direction of the initial beam 111 and the target direction. The laser radar compensation and alignment device 100 obtained by the above design, by setting a plurality of beam displacement elements with simple structure and easy installation, has moderate sensitivity, high precision and good stability, and can greatly reduce the assembly tolerance required to be observed by the receiving focusing or beam splitting elements of the laser radar, thereby improving the detection performance of the laser radar.
[0040] In one possible implementation of the present application, the first beam displacement element 120 is an optical plate, and the second beam displacement element 130 is a wedge prism.
[0041] Specifically, the laser radar compensation alignment device 100 includes a first beam displacement element 120 and a second beam displacement element 130, which can produce translation and tilt of light; wherein the first beam displacement element 120 is an optical flat plate, and the second beam displacement element 130 is a wedge-shaped prism. Of course, according to actual installation requirements, the first beam displacement element 120 can be set as a wedge-shaped prism and the second beam displacement element 130 can be set as an optical flat plate.
[0042] Among them, Figure 2 As shown, according to the light refraction principle of the optical plate, the optical axis of the initial light beam 111 can be translated by a distance s to generate a first outgoing light beam 121 with the same propagation direction and interval s. The specific formula for light displacement according to the optical plate is:
[0043]
[0044] In the above formula, t is the thickness of the optical plate, the incident angle θ is the angle between the light incident on the plate and its normal, and n is the refractive index of the optical plate. According to the above formula, different incident angles θ correspond to different light offset distances s. Figure 5 As shown in FIG. 1 , the displacement derivative ds / dθ of the function of the incident angle θ is shown. The figure shows the change of the displacement distance s relative to the incident angle θ (thetha). In the figure, n=1.6 and t=2 are taken. The figure also shows the sensitivity of the incident angle change to the displacement. Among them, the light displacement trend of the optical plate is slow when adjusted from -25 to 25 degrees, and the displacement distance can reach about 1mm.
[0045] Please refer to Figure 6 , Figure 6 This is the receiving system of the existing laser radar without compensation alignment system. Taking the initial light beam incident at 111 degrees as the reference, according to the relationship that the optical angle is equal to twice the mechanical angle, the reflector light offset formula (clockwise is positive) can be known:
[0046] s=L·tan 2θ
[0047] Where L is the distance between the wedge prism and the detector 150 target surface, and θ is the rotation angle of the wedge prism. Figure 4 , Figure 4 It is a sensitivity curve related to the rotation angle and displacement. L=20mm is taken in the figure. The rate of change of displacement with respect to angle is large, and the sensitivity is high. According to the above relationship, it can be known that when L=10mm, under small angle adjustment, the typical reflector controls the light displacement sensitivity of 20μm / mrad, 2mrad / mrad. The laser radar compensation and alignment device 100 provided in the present application has an optical flat plate compensation of n=1.6, t=2mm, and a typical light displacement sensitivity of 0.75μm / mrad. It can be seen that the laser radar compensation and alignment device 100 provided in the present application has moderate sensitivity, high precision, and good stability.
[0048] Please refer to Figure 3 , Figure 3 This is the refraction principle of the wedge prism. The wedge prism can refraction the incident angle of the incident surface of the wedge prism to i The light is deflected, and the light can also be regarded as having an angle θ with the initial optical axis. i The light ray has an angle of incidence θ with the exit surface of the wedge prism. o At a distance S from the second surface, the light beam is offset by a distance R. This can be achieved by controlling the position and angle of the incident light beam relative to the first surface and adjusting the wedge prism to rotate around the central axis Z with a radius of R. According to the light refraction formula of the wedge prism:
[0049] R=S·tanθ0+T·tan(θ i -θ r )
[0050] In the above formula, T is the center thickness of the wedge prism.
[0051] The propagation direction of the second outgoing light 131 finally emitted after translation and deflection by the first beam displacement element 120 and the second beam displacement element 130 is closer to the center of the outgoing light axis of the beam splitter element 140 , and is evenly separated by the beam splitter element 140 and guided to the surface of the detector 150 .
[0052] Furthermore, an anti-reflection film is provided on the incident surface and / or the exit surface of the optical flat plate.
[0053] Specifically, the incident surface and the exit surface of the optical plate are provided with anti-reflection films. The operating wavelengths of the laser radar are usually 905nm, 940nm, and 1550nm. Coating the anti-reflection film on the surface of the optical plate can increase the transmittance of the corresponding wavelength, thereby further improving the detection performance of the laser radar.
[0054] In a possible implementation scheme of the present application, the detector 150 is a plurality of evenly distributed sub-detectors 151 , the number of the plurality of sub-detectors 151 corresponds one-to-one to the number of the plurality of sub-beams 141 , and the sub-beams 141 are incident on the sub-detectors 151 one-to-one.
[0055] Specifically, Figure 1 As shown, the detector 150 is a plurality of evenly distributed sub-detectors 151, and the plurality of sub-detectors 151 are arranged at intervals in the vertical direction. The number of the plurality of sub-detectors 151 corresponds one-to-one to the number of the plurality of sub-beams 141, and the plurality of sub-beams 141 obtained by the beam splitting element 140 are incident on each sub-detector 151 one-to-one and are received by the sub-detector 151.
[0056] In another possible implementation of the present application, the detector 150 is a planar array detector 152 , and the plurality of sub-beams 141 are correspondingly incident on a detection surface of the planar array detector 152 .
[0057] Specifically, Figure 1 As shown, the detector 150 can be configured as an integral planar array detector 152 , and a plurality of detection surfaces are provided on the surface of the planar array detector 152 . The plurality of split light beams 141 obtained by the beam splitting element 140 can be incident on the planar array detector 152 and received by the detection surface of the planar array detector 152 .
[0058] Another aspect of the utility model provides a laser radar, which includes the above-mentioned laser radar compensation and alignment device 100. As a high-precision and high-reliability distance measurement device, laser radar has been widely used in the fields of autonomous driving, intelligent manufacturing, robotics, etc. Among them, the specific structure and beneficial effects of the laser radar compensation and alignment device 100 have been introduced in detail above and will not be repeated here. The laser radar obtained by the above-mentioned greatly reduces the assembly tolerance required to be complied with by the spectrometer 140 of the laser radar compensation and alignment device 100, thereby improving the detection performance of the laser radar.
[0059] The above description is only an optional embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
[0060] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.
Claims
1. A laser radar compensation alignment device, characterized in that: The laser radar comprises a receiving optical element, a first beam displacement element and a second beam displacement element which are arranged in sequence from the object side to the image side. The receiving optical element is used to receive an initial beam emitted by a laser radar to a target and reflected by the target carrying information of the target. The initial beam is refracted by the first beam displacement element to be a first emitted light beam; the first emitted light beam is refracted by the second beam displacement element to be a second emitted light beam, and an angle between a main optical axis of the second emitted light beam and a direction of the target object is smaller than an angle between a main optical axis of the initial beam and a direction of the target object.
2. The laser radar compensation alignment device according to claim 1, characterized in that: The first beam displacement element is an optical plate, and the second beam displacement element is a wedge prism.
3. The laser radar compensation alignment device according to claim 1, characterized in that: The first beam displacement element is a wedge prism, and the second beam displacement element is an optical plate.
4. The laser radar compensation alignment device according to claim 2 or 3, characterized in that: The incident surface and / or the exit surface of the optical flat plate is provided with an anti-reflection film.
5. The laser radar compensation alignment device according to claim 1, characterized in that: The laser radar compensation and alignment device also includes a detector, which is arranged on the light-emitting side of the second beam displacement element, and the second output light emitted by the second beam displacement element is received by the detector.
6. The laser radar compensation alignment device according to claim 5, characterized in that: The laser radar compensation and alignment device also includes a spectroscopic element, which is arranged between the second beam displacement element and the detector. The second output light emitted by the second beam displacement element is divided into a plurality of sub-beams emitted in multiple directions by the spectroscopic element, and the plurality of sub-beams are received by the detector.
7. The laser radar compensation alignment device according to claim 6, characterized in that: The detector is a plurality of evenly distributed sub-detectors, the number of the plurality of sub-detectors corresponds one-to-one to the number of the plurality of sub-light beams, and the sub-light beams are incident on the sub-detectors one-to-one.
8. The laser radar compensation alignment device according to claim 6, characterized in that: The detector is a planar array detector, and the plurality of sub-light beams are correspondingly incident on the detection surface of the planar array detector.
9. The laser radar compensation alignment device according to claim 6, characterized in that: The optical axis center of the beam splitter element is aligned with the optical axis center of the receiving optical element through the first beam displacement element and the second beam displacement element.
10. A laser radar, characterized in that: It comprises the laser radar compensation alignment device as described in any one of claims 1-9.