A laser active measurement module and laser radar

Abstract

The application discloses a kind of laser active measurement module and laser radar, comprising: laser signal transmitting module, laser signal receiving module, transmitting optical path module, receiving optical path module, the transmitting optical path module has transmitting lens, the receiving optical path module has receiving lens;The receiving lens and the transmitting lens are used to realize parallel light path of transceiver, the receiving lens and the transmitting lens are placed staggered forward and backward along the direction of optical path extension, the lens end cross section width of the laser active measurement module increases step by step.This application can improve receiving caliber under the premise of the same scanning field range, or improve scanning field range under the premise of the same receiving caliber.The signal intensity of the scanning field of the laser radar of the application is symmetric and balanced on both sides of the principal axis, and the data acquisition quality is high.

Description

Technical Field

[0001] This invention relates to the field of lidar technology based on photoelectric detection, and in particular to a laser active measurement module and lidar. Background Technology

[0002] LiDAR has been widely used in various fields due to its high precision and high resolution measurement advantages. Especially in the field of autonomous vehicles, LiDAR is an indispensable core sensor, whether for calibration, testing, or practical applications.

[0003] The industry's demand for LiDAR is further reflected in improving the field of view and increasing the aperture of the optical system, in order to better adapt to the in-vehicle application environment of autonomous vehicles and cope with the specific application environment of vehicle driving.

[0004] A problem that those skilled in the art urgently need to solve is to improve the effective receiving aperture. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a laser active measurement module that increases the effective receiving aperture under the same scanning angle, or increases the scanning field of view under the premise of the same receiving aperture.

[0006] Furthermore, the signal intensity on both sides of the main optical axis of the scanning field of view of the lidar of the present invention is symmetrical and balanced.

[0007] Furthermore, this results in high-quality data collection.

[0008] This invention discloses a laser active measurement module, comprising: a laser signal emitting module, a laser signal receiving module, a emitting optical path module, and a receiving optical path module, wherein the emitting optical path module has a emitting lens and the receiving optical path module has a receiving lens;

[0009] The receiving lens and the transmitting lens are used to realize parallel optical paths for transmission and reception. The receiving lens and the transmitting lens are staggered along the direction of optical path extension. The width of the lens end cross section of the laser active measurement module increases in a stepped manner.

[0010] The cross-sectional width of the laser active measurement module at the transmitting lens is greater than that at the receiving lens.

[0011] The transmitting lens and the receiving lens are set parallel to each other.

[0012] The transmitting lens is retracted relative to the receiving lens in the receiving direction, forming an optical path accommodating space; or

[0013] The receiving lens is moved back relative to the transmitting lens in the receiving direction to form an optical path accommodating space.

[0014] The retraction distance of the transmitting lens is greater than the aperture of the transmitting lens.

[0015] The aperture of the receiving lens is more than twice the aperture of the transmitting lens.

[0016] The laser active measurement module further includes a scanning mirror, and the emitting optical path module and the receiving optical path module are arranged adjacent to each other and on the same side of the scanning mirror.

[0017] The transmitting lens is positioned near the light emission direction of the scanning mirror, while the receiving lens is positioned away from the light emission direction; or

[0018] The receiving lens is positioned near the light-emitting direction of the scanning mirror, while the transmitting lens is positioned away from the light-emitting direction.

[0019] The extension line of one edge of the physical aperture of the receiving lens passes through the rotation axis of the scanning mirror.

[0020] The sum of the physical apertures of the receiving lens and the transmitting lens is less than or equal to half the diagonal of the scanning mirror cross-section.

[0021] The optical axis of the receiving lens forms an acute angle with the positive light output direction N of the scanning mirror.

[0022] The laser active measurement module has a dual-optical-path structure, which includes a transmitting optical path module and a receiving optical path module; or,

[0023] The laser active measurement module has a three-optical-path structure, which includes two transmitting optical path modules and one receiving optical path module, or one transmitting optical path module and two receiving optical path modules.

[0024] The scanning mirror has the dual-optical-path structure on both sides; or,

[0025] The scanning mirror has the three-optical-path structure on both sides.

[0026] The increase in the effective receiving aperture of the receiving lens, ΔK, is:

[0027]

[0028] ih is the retraction distance of the transmitting lens, if is the aperture of the transmitting lens, β is the scanning angle of the scanning mirror, β0 is the starting working angle, point f is the rear step vertex of the optical path accommodating space, point h is the front step vertex of the optical path accommodating space, and RO is the edge echo signal in the working mode.

[0029] The present invention also discloses a lidar, including the aforementioned active laser measurement module.

[0030] This invention enables an increase in effective receiving aperture, or an increase in scanning field of view, while maintaining the same scanning angle. Furthermore, the signal intensity on both sides of the principal optical axis of the scanning field of view of the lidar of this invention is symmetrically balanced, resulting in high data acquisition quality. Attached Figure Description

[0031] Figure 1 , 2A Figure 2B shows a cross-sectional view of the laser active measurement module of the present invention.

[0032] Figures 3A-3H The diagram shown is a schematic of the optical path of a prior art structure.

[0033] Figure 4 The diagram shown is an optical path schematic of an embodiment of the present invention.

[0034] Figure 5 The diagram shown is an optical path schematic of another embodiment of the structure of the present invention;

[0035] Figure 6 The diagram shown is an optical path schematic of another embodiment of the structure of the present invention. Detailed Implementation

[0036] The following description of the implementation process of the technical solution of the present invention with reference to specific embodiments is not intended to limit the present invention.

[0037] This invention discloses a laser active measurement module and a lidar. Compared with existing technologies, this invention increases the effective receiving aperture at the same scanning angle, or, under the premise of the same effective receiving aperture, increases the effective scanning angle range. Simultaneously, the lidar of this invention combines a compact structure with a wide field of view, and the lidar's transmitting and receiving apertures are balanced, resulting in high data acquisition quality.

[0038] like Figure 1 , 2A Figure 2B shows a cross-sectional view of the laser active measurement module of the present invention.

[0039] The laser active measurement module 1 of the present invention includes a laser signal transmitting module 10, a laser signal receiving module 30, a transmitting optical path module 20, and a receiving optical path module 40. The transmitting optical path module 20 has a transmitting lens 21, and the receiving optical path module 40 has a receiving lens 41.

[0040] The laser signal emitted by the laser signal emitting module 10 is emitted from the emitting lens 21 via the emitting optical path module 20, and the echo signal is received by the laser signal receiving module 30 via the receiving lens 41.

[0041] The transmitting optical path module 20 and the receiving optical path module 40 are arranged adjacent to each other, and the receiving lens 41 and the transmitting lens 21 form a parallel optical path for transmission and reception, such as Figure 1 As shown, the transmitting optical path T and the receiving optical path R are parallel to each other. The transmitting optical path T is perpendicular to the transmitting lens 21.

[0042] In this invention, the receiving lens 41 and the transmitting lens 21 are staggered along the optical path extension direction. That is, the receiving lens 41 is positioned along P1, and the transmitting lens 21 is positioned along P2. P1 and P2 are staggered along the optical path extension direction P. Figure 1 P is parallel to T and parallel to R.

[0043] Meanwhile, the transmitting lens 21 and the receiving lens 41 are arranged parallel to each other, that is, the straight lines P1 and P2 are parallel to each other.

[0044] The width of the lens end cross-section of the laser active measurement module 1 increases in a stepped manner. Specifically, the transmitting lens 21 is retracted relative to the receiving lens 41 in the direction of the receiving optical path R, forming an optical path accommodating space fghi.

[0045] The lens end cross-sectional width D1 measured by the laser active measurement module 1 at the transmitting lens 21 is greater than the lens end cross-sectional width D2 measured at the receiving lens.

[0046] The laser active measurement module 1 also includes a scanning mirror 50 and an optical window 60, with the emitting optical path module 20 and the receiving optical path module 40 located on the same side of the scanning mirror 50.

[0047] The scanning mirror 50 rotates to continuously reflect the laser signal emitted by the laser signal emitting module 10 and make it penetrate the optical window 60 to illuminate the environment. Figure 1 In this context, N represents the positive light output direction of the scanning mirror, i.e. Figure 3A The scanning field of view is in the 0° direction.

[0048] The transmitting lens 21 is located on the side adjacent to the optical window 60, that is, the transmitting lens 21 is located near the positive light emission direction N of the scanning mirror, and the receiving lens 41 is located on the side away from the optical window 60, that is, away from the positive light emission direction N.

[0049] The scanning mirror 50 preferably has four mirror surfaces.

[0050] In the prior art, the receiving lens 41 and the transmitting lens 21 are located on the same straight line P1 (e.g., Figure 2A As shown in the figure, at this time, point g of the laser active measurement module is the vertex of the structure edge. In order to avoid being blocked by the structure of the laser active measurement module itself, all working signals need to fly in the space outside point g.

[0051] like Figure 3A The diagram shown is a schematic of the optical path of the existing technology structure.

[0052] When the scanning mirror 50 is at a specific scanning angle, a corresponding echo signal from the environment returns in the same direction. This echo signal typically covers a large spot area. Figure 3A The signals R0-R4 are representative. The echo signals R0-R4 are parallel to each other, and their angles are all related to the rotation angle of the scanning mirror 50 at this time.

[0053] The projection range K of the receiving lens 41 on the mirror surface of the scanning mirror 50 corresponds to the actual physical aperture of the receiving lens 41.

[0054] The echo signal R0 is blocked by the structure of the laser active measurement module itself, and cannot reach the surface of the scanning mirror 50, nor can it be incident on the receiving lens 41.

[0055] The echo signal R1 is tangent to point g and can reach the surface of the scanning mirror 50. It is then incident perpendicularly on the receiving lens 41 and received by the laser signal receiving module 30.

[0056] The echo signal R2 can reach the surface of the scanning mirror 50, and the echo signal R2 just illuminates one edge of the projection of the receiving lens 41 on the mirror surface. At this time, the echo signal R2 can be incident on the receiving lens 41 and received by the laser signal receiving module 30.

[0057] The echo signal R3 can reach the surface of the scanning mirror 50, but the echo signal R3 is outside the projection range K and cannot enter the receiving lens 41, so it cannot be received by the laser signal receiving module 30.

[0058] The echo signal R4 cannot reach the surface of the scanning mirror 50 and cannot be received by the laser signal receiving module 30.

[0059] Therefore, the existing technology structure can only enable the signal reaching the projection range K1 to be received by the laser signal receiving module 30. That is, the signal located between the echo signals R1 and R2 can be received by the laser signal receiving module 30. Thus, the effective receiving aperture of the receiving lens 41 is K1.

[0060] like Figure 3B The diagram shown is an optical path schematic of the structure of this invention. Figure 3B As shown Figure 3A The scanning mirrors rotate at the same angle, the transmission and reception conditions are the same, and the angle of the echo signal is the same. Relative to... Figure 3A The difference is that, because the transmitting lens 21 of the laser active measurement module is moved back, an optical path accommodating space fghi is formed, so that the echo signal R0 inside the echo signal R1 is no longer blocked and can reach the mirror surface of the scanning mirror 50.

[0061] Therefore, the structure of the present invention enables the signal reaching the projection range K2 to be received by the laser signal receiving module 30, that is, the signal located between the echo signals R0 and R2 can be received by the laser signal receiving module 30. Thus, the effective receiving aperture of the receiving lens 41 is K2, where K2>K1.

[0062] It can be seen that the structure of the laser active measurement module 1 of the present invention expands the effective receiving aperture of the receiving lens 41 during the scanning process under the same scanning angle, while keeping the physical aperture of the receiving lens 41 unchanged, thereby enhancing the signal strength and improving the signal receiving efficiency.

[0063] For the increase in effective receiver aperture, please refer to... Figure 3C In the diagram, the dashed scanning mirror 50 represents the initial position (considered a 0-degree rotation), at which point the two mirror surfaces are parallel to the receiving lens 41. Rotating clockwise to the position indicated by the solid line in the diagram, the echo signal R1 is either an edge signal that the receiving lens 41 can receive in the existing technology structure, or the first signal that the entire lidar can receive when it starts working. The echo signal R1 is tangent to point g and illuminates the outermost edge of the projection of the receiving lens 41 onto the mirror surface. The angle through which the scanning mirror 50 has rotated relative to the initial position corresponding to this echo signal R1 is the scanning angle β0 of the existing technology structure. Between the initial position and the scanning angle β0 at which the scanning mirror 50 can begin receiving signals, no echo signal can be received by the laser signal receiving module 30, and it is in a non-working mode. β0 is the starting working angle.

[0064] The echo signal R0 is the edge echo signal that can be received by the laser signal receiving module 30 when a scanning angle β0 is generated under the structure of this invention. The increase in aperture at this scanning angle β0 is... Figure 3C ΔK in.

[0065] When the size and position of the scanning mirror 50, and the length and position of if, ih, D1, and D2 are determined, β0 is a uniquely determined value.

[0066] The value of ΔK is related to the shape of the optical path containment space fghi.

[0067] When ∠fhi≤2β0, the echo signal R0 is tangent to point h, such as Figure 3C As shown, gj is the distance between echo signals R0 and R1, and ΔK in the figure is the distance between echo signals R0 and R1 after reflection. Therefore, ΔK = gj.

[0068] When the scan angle is β0, the angle between the echo signal R1 and the extension of fg is 2β0, therefore...

[0069] ∠jgh=2β0, at this time ΔK=gj=gh*cos 2β0=if*cos2β0.

[0070] When ∠fhi ≥ 2β0, the echo signal R0 is tangent to point f, such as Figure 3D As shown, gj is the distance between echo signals R0 and R1, and ΔK in the figure is the distance between echo signals R0 and R1 after reflection. Therefore, ΔK = gj.

[0071] When the scanning angle is β0, the angles between the echo signals R0 and R1 and the extension of fg are both 2β0, so ∠gfj=2β0, and at this time ΔK=gj=gf*sin2β0=ih*sin2β0.

[0072] When the real-time scanning angle β is located between scanning angle β0 and 45°, the value of ΔK is related to the shape of the optical path containment space fghi. The aperture increase ΔK is calculated as follows.

[0073] When ∠fhi≤2β0, the outermost echo signal R0 is always tangent to point h, such as Figure 3E As shown, gj is the distance between echo signals R0 and R1, and ΔK in the figure is the distance between echo signals R0 and R1 after reflection. Therefore, ΔK = gj.

[0074] The angle between the echo signal R1 and the extension of fg is 2β, so ∠jgh=2β. At this time, ΔK=gj=gh*cos 2β=if*cos2β.

[0075] When ∠fhi > 2β0, continue to divide into two segments; when β0 < β ≤ ∠fhi / 2, as shown... Figure 3F As shown, the calculation of ΔK is as follows: Figure 3D The echo signal R0 is always tangent to point f, and ΔK = gj = gf*sin2β = ih*sin2β.

[0076] When ∠fhi / 2 < β ≤ 45°, the echo signal R0 at the outermost edge is always tangent to point h, such as Figure 3G As shown, ΔK = gj = gh * cos 2β = if * cos2β.

[0077] As can be seen, the structure of this invention ensures that the increase in aperture ΔK is greater than zero during the rotation of one mirror surface of the scanning mirror (from β0 to 45°). Therefore, the structure of this invention increases the effective receiving aperture at the same scanning angle.

[0078]

[0079] ih is the retraction distance of the transmitting lens, if is the aperture of the transmitting lens, β is the scanning angle of the scanning mirror, β0 is the starting working angle, point f is the rear step vertex of the optical path accommodating space, point h is the front step vertex of the optical path accommodating space, and RO is the edge echo signal in the working mode.

[0080] In addition, the present invention can expand the working scanning field of view under the premise of the same effective receiving aperture.

[0081] In the existing technology, Figure 3A The scanning angle where the echo signal R1 is located corresponds to the maximum field of view of the laser active measurement module in its working mode, and α1 is the tilt angle of the echo signal R1 relative to the reference line.

[0082] In this invention, such as Figure 3H As shown, Figure 3H Selection and Figure 3A With the same effective receiving aperture K1, the laser active measurement module's transmitting lens 21 is moved back, forming an optical path accommodating space fghi, which further expands the maximum field of view until it is tangent to point f. That is, the echo signal that can be received at the outermost edge changes from R1 to R1', and the tilt angle of R1' is α2, where α2 < α1. Figure 3H The scheme shown is relatively Figure 3A The scheme shown maintains the same effective receiving aperture, but expands the working scanning field of view.

[0083] In an optimized embodiment, the extension line of the inner edge of the physical aperture K of the receiving lens 41 passes through the rotation axis O of the scanning mirror 50. The sum of the physical apertures of the receiving lens 41 and the transmitting lens 21 is less than or equal to half of the diagonal 2L of the cross-section of the scanning mirror 50, so that the mirror surface of the scanning mirror 50 can be fully utilized when the scanning angle β is 45°, thereby improving the effective transmitting aperture and the effective receiving aperture.

[0084] In an optimized embodiment, the retraction distance ih of the transmitting lens 21 is greater than the aperture if of the transmitting lens. Correspondingly Figure 3E In this embodiment, the outermost echo signal R0 is always tangent to point h, and is not constrained by point f during the scanning angle change, resulting in a smoother increase in aperture.

[0085] In one optimized embodiment, the aperture of the receiving lens 41 is larger than the aperture of the transmitting lens. Specifically, the aperture of the receiving lens 41 is more than twice the aperture of the transmitting lens, which helps to increase the average effective receiving aperture. The lens end cross-sectional width D2 measured at the receiving lens is equal to half the side length of the scanning mirror 50. The distance L between the center O of the scanning mirror 50 and the receiving lens 41 is to minimize the size of the device, making it compact and lightweight.

[0086] In one optimized embodiment, the laser signal transmitting module 10, the laser signal receiving module 30, the transmitting optical path module 20, and the receiving optical path module 40 can be stacked in the Z direction. Specifically, the laser active measurement module has a three-optical-path structure, such as... Figure 3B As shown, two transmitting optical path modules are stacked in the Z direction, such that each of the two transmitting optical path modules corresponds to one receiving optical path module, thereby expanding the field of view in the Z direction. This structure can be considered a three-optical-path structure.

[0087] Alternatively, two receiving optical path modules can be stacked in the Z direction, such that the two receiving optical path modules correspond to one transmitting optical path module.

[0088] In the Z direction, there is no stacking, and the structure of one transmitting optical path module corresponding to one receiving optical path module is a dual optical path structure.

[0089] In one optimized embodiment, the dual-optical-path structure can be respectively provided on both sides of the scanning mirror 50, such as... Figure 4 As shown, this ensures that the signal intensity on both sides of the main optical axis is completely symmetrical and balanced. Alternatively, the three-optical-path structure can also be set on both sides of the scanning mirror 50. This further expands the scanning field of view in the XY plane.

[0090] In one optimized embodiment, such as Figure 5 As shown, relative Figure 3B The transmitting and receiving positions are swapped, and the receiving lens is moved back relative to the transmitting lens in the receiving direction to form an optical path accommodating space fghi.

[0091] As the scanning mirror 50 rotates clockwise, in the prior art, the laser signal T1 emitted from the laser signal emitting module 10 is not blocked by point g and is successfully emitted into the environment, and the scanning operation begins from this point. In contrast, in this invention, the laser signal T1' is not blocked by point f and is successfully emitted into the environment.

[0092] It is evident that the transmission signal of this invention starts working earlier and covers a wider field of view. Simultaneously, during operation, the transmission aperture K4 almost always reaches the actual physical transmission aperture, resulting in a larger transmission aperture and an effective receiving aperture on the outside, facilitating reception and ensuring the receiving aperture is not obstructed.

[0093] In one optimized embodiment, such as Figure 6 As shown, relative Figure 3B The transmitting and receiving assembly rotates clockwise, and the optical axis of the receiving lens 41 forms an acute angle ε with the light emission direction N of the scanning mirror. This positive light emission direction N is... Figure 3B The light emission direction is N, which is perpendicular to the optical window 60. Figure 6It allows for adjustment of the specific orientation of the scanning field of view to adapt to specific application environments. At the same time, it can also capture two different angle ranges on both sides of the positive light output direction N (field of view 0°), thereby capturing a segment with a more uniform echo signal distribution and improving the measurement accuracy of the lidar.

[0094] The present invention also discloses a lidar, including the above-mentioned active laser measurement module.

[0095] This invention enables an increase in effective receiving aperture, or an increase in scanning field of view, while maintaining the same effective receiving aperture. Simultaneously, it achieves high data acquisition quality.

[0096] The above embodiments are only used to describe the technical solutions of the present invention and are not to be regarded as limitations on the present invention.

Claims

1. A laser active measurement module, characterized in that, include: The system includes a laser signal transmitting module, a laser signal receiving module, a transmitting optical path module, a receiving optical path module, a scanning mirror, and an optical window. The rotating scanning mirror continuously reflects the laser signal emitted by the laser signal transmitting module and allows it to penetrate the optical window. The transmitting optical path module has a transmitting lens, and the receiving optical path module has a receiving lens; The receiving lens and the transmitting lens are used to realize parallel optical paths for transmission and reception. The receiving lens and the transmitting lens are staggered along the direction of optical path extension to form an optical path accommodating space. This optical path accommodating space allows some echo signals far from the positive light output direction to reach the surface of the scanning mirror. The width of the lens end cross section of the laser active measurement module increases in a stepped manner.

2. The laser active measurement module of claim 1, wherein, The cross-sectional width of the laser active measurement module at the transmitting lens is greater than that at the receiving lens.

3. The laser active measurement module of claim 1, wherein, The transmitting lens is retracted relative to the receiving lens in the receiving direction to form the optical path accommodating space; or The receiving lens is retracted relative to the transmitting lens in the receiving direction to form the optical path accommodating space.

4. The laser active measurement module of claim 3, wherein, The retraction distance of the transmitting lens is greater than the aperture of the transmitting lens.

5. The laser active measurement module of claim 1 or 3 or 4, wherein, The aperture of the receiving lens is more than twice the aperture of the transmitting lens.

6. The laser active measurement module of claim 3, wherein, The transmitting optical path module and the receiving optical path module are arranged adjacent to each other and on the same side of the scanning mirror.

7. The laser active measurement module as described in claim 6, characterized in that, The transmitting lens is positioned near the light emission direction of the scanning mirror, while the receiving lens is positioned away from the light emission direction; or The receiving lens is positioned near the light emission direction of the scanning mirror, while the transmitting lens is positioned away from the light emission direction.

8. The laser active measurement module of claim 6, wherein, The extension line of one edge of the physical aperture of the receiving lens passes through the rotation axis of the scanning mirror.

9. The laser active measurement module of claim 8, wherein, The sum of the apertures of the receiving lens and the transmitting lens is less than or equal to half the diagonal of the scanning mirror cross-section.

10. The laser active measurement module of claim 6, wherein, The optical axis of the receiving lens forms an acute angle with the positive light output direction N of the scanning mirror.

11. The laser active measurement module of claim 1 or 6, wherein, The laser active measurement module has a dual-optical-path structure, which includes a transmitting optical path module and a receiving optical path module; or, The laser active measurement module has a three-optical-path structure, which includes two transmitting optical path modules and one receiving optical path module, or one transmitting optical path module and two receiving optical path modules.

12. The laser active measurement module of claim 11, wherein, The scanning mirror has the dual-optical-path structure on both sides; or, The scanning mirror has the three-optical-path structure on both sides.

13. The laser active measurement module as described in claim 6, characterized in that, The increase in the effective receiving aperture of the receiving lens, ΔK, is: ih is the retraction distance of the transmitting lens, if is the aperture of the transmitting lens, β is the scanning angle of the scanning mirror, β0 is the starting working angle, point f is the rear step vertex of the optical path accommodating space, point h is the front step vertex of the optical path accommodating space, and RO is the edge echo signal in the working mode.

14. A lidar, comprising: Includes the laser active measurement module as described in any one of claims 1-13.

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