LiDAR

Abstract

This application provides a lidar, which includes a laser emitting plate, a laser receiving plate, a emitting lens group, a receiving lens group, a semi-transparent mirror, and a wide-angle lens group. The first emitting lens in the emitting lens group is the same as the second receiving lens in the receiving lens group, and the second emitting lens in the emitting lens group is the same as the first receiving lens in the receiving lens group. This lidar achieves a large elevation field of view through the emitting lens group, receiving lens group, semi-transparent mirror, and wide-angle lens group. Simultaneously, because the optical elements in the receiving and emitting paths of this lidar are identical, the influence of optical distortion on the received laser beam is greatly reduced, improving the ranging accuracy and range capability of the lidar.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and more particularly to a lidar. Background Technology

[0002] With the development and application of lidar technology, the market demand for lidar with large elevation field of view is increasing. However, the larger the elevation field of view, the greater the inherent optical distortion of the optical system in the lidar. In particular, in lidar with an elevation field of view of more than 100°, the optical distortion can exceed 30%. This optical distortion will cause bending and other effects on the transmitted and received laser beams in the lidar, thereby reducing the amplitude of the received laser beam and decreasing the ranging accuracy and range measurement capability of the lidar.

[0003] Therefore, how to enable lidar to have a large pitch field of view while reducing the impact of optical distortion on the received laser beam has become an urgent technical problem to be solved. Summary of the Invention

[0004] The main objective of this application is to provide a lidar that has both a large pitch field of view and reduces the influence of optical distortion on the received laser beam, thereby improving the ranging accuracy and range measurement capability of the lidar.

[0005] This application provides a lidar, the lidar comprising:

[0006] A laser emitting plate, the laser emitting plate including at least one light-emitting unit, the light-emitting unit being used to emit laser light;

[0007] A laser receiver plate, the laser receiver plate including at least one photosensitive unit;

[0008] The emitting lens group includes a first emitting lens and a second emitting lens;

[0009] The receiving lens group includes a first receiving lens and a second receiving lens; wherein the first transmitting lens and the second receiving lens are the same lens, and the second transmitting lens and the first receiving lens are the same lens;

[0010] Semi-transparent and semi-reflective mirror and wide-angle lens assembly;

[0011] The laser beam is collimated by the first emitting lens and the second emitting lens in sequence, and then directed towards the semi-transparent mirror. The laser beam passing through the semi-transparent mirror is amplified by the expanding lens group and then directed towards the object under test. The laser beam reflected back by the object under test is focused onto the semi-transparent mirror through the expanding lens group, and then reflected by the semi-transparent mirror to the first receiving lens. After being focused by the first receiving lens and the second receiving lens, the laser beam is incident on at least one of the photosensitive units.

[0012] In one embodiment, at least one of the light-emitting units forms a light-emitting area on the laser emitting plate, and at least one of the photosensitive units forms a photosensitive area on the laser receiving plate; wherein the light-emitting area and the photosensitive area are the same size in the vertical direction and their tops are aligned, and the vertical direction is parallel to the rotation axis of the lidar.

[0013] In one embodiment, the size of the photosensitive area in the horizontal direction is greater than or equal to the size of the light-emitting area in the horizontal direction, wherein the horizontal direction is perpendicular to the rotation axis of the lidar.

[0014] In one embodiment, the lidar further includes a reflector, through which laser light passing through the semi-transparent mirror is reflected onto the expanding lens assembly, wherein the reflector is tilted at an angle α relative to the vertical direction, and the expanding lens assembly is tilted at an angle 2α relative to the vertical direction, wherein the vertical direction is parallel to the rotation axis of the lidar.

[0015] In one embodiment, the reflector is disposed at the aperture of the emitting lens group, and the aperture is optimally disposed at the edge of the rotating stage of the lidar.

[0016] In one embodiment, α = 15°.

[0017] In one embodiment, when the expanding lens group is tilted at an angle of 2α relative to the vertical direction, the pitch field of view of the lidar is -30° to 90°.

[0018] In one embodiment, the expanding lens group includes at least one expanding lens, and the refractive index relationship between the expanding lens, the first emitting lens, and the second emitting lens satisfies the following equation:

[0019] n1 = n2, n2 > n3

[0020] Wherein, n1, n2, and n3 are the refractive indices of the first emitting lens, the second emitting lens, and the expanding lens, respectively.

[0021] In one embodiment, the radius of curvature of the incident surface of the first emitting lens is smaller than the radius of curvature of the exit surface of the first emitting lens, and both are negative values; the radius of curvature of the incident surface of the second emitting lens is positive, and the radius of curvature of the exit surface of the second emitting lens is negative; the expanding lens group includes at least one expanding lens, wherein the radius of curvature of the side of the expanding lens facing the object to be measured is smaller than the radius of curvature of the side facing away from the object to be measured, and both are positive values.

[0022] In one embodiment, the semi-transparent mirror includes a semi-transparent mirror sheet or a semi-transparent prism.

[0023] This application provides a lidar that achieves a large elevation field of view through a transmitting lens group, a receiving lens group, a semi-transparent mirror, and an expanding lens group. Furthermore, by making the first transmitting lens in the transmitting lens group and the second receiving lens in the receiving lens group identical, and by making the second transmitting lens in the transmitting lens group and the first receiving lens in the receiving lens group identical, the optical elements in the receiving and transmitting paths of the lidar are identical. The effects of optical distortion in the transmitting optical path on the bending of the laser beam are weakened by optical distortion in the receiving optical path, thereby reducing the impact of optical distortion on the amplitude and other aspects of the received laser beam, and improving the ranging accuracy and range capability of the lidar. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the optical structure of a lidar in one embodiment of this application;

[0026] Figure 2 for Figure 1 The diagram shows the structure of the laser transmitter and laser receiver in the lidar.

[0027] Figure 3 This is a schematic diagram of the lidar structure in another embodiment of this application;

[0028] Figure 4 for Figure 3 The diagram shows a cross-sectional structure of a lidar.

[0029] Figure 5 for Figure 3 A schematic diagram of the optical structure of the lidar shown;

[0030] Figure 6 for Figure 3 The diagram shows the field of view of the lidar.

[0031] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] Please refer to Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the optical structure of a lidar provided in one embodiment of this application. Figure 2 for Figure 1 The diagram shows the structure of the laser emitting plate and laser receiving plate in the lidar. The lidar includes a laser emitting plate 10, a laser receiving plate 20, a emitting lens group 30, a receiving lens group 40, a semi-transparent mirror 50, and a wide-angle lens group 60.

[0035] The laser emitting plate 10 includes at least one light-emitting unit 11, which is used to emit laser light.

[0036] The laser receiving plate 20 includes at least one photosensitive unit 21 for receiving the returned laser light.

[0037] The emitting lens group 30 includes a first emitting lens 31 and a second emitting lens 32. The laser emitted by the light-emitting unit 11 is collimated by the first emitting lens 31 and the second emitting lens 32 in sequence.

[0038] In one embodiment, the radius of curvature of the incident surface (i.e., the side facing the laser emitting plate 10) of the first emitting lens 31 is smaller than the radius of curvature of the exit surface (i.e., the side facing the second emitting lens 32), and both are negative values; the radius of curvature of the incident surface (i.e., the side facing the first emitting lens 31) of the second emitting lens 32 is positive, and the radius of curvature of the exit surface (i.e., the side facing the semi-transparent mirror 50) of the second emitting lens 32 is negative.

[0039] The collimated laser beam is incident on a semi-transparent and semi-reflective mirror 50. This semi-transparent and semi-reflective mirror 50 allows 50% of the laser beam to be transmitted and 50% to be reflected. This semi-transparent and semi-reflective mirror 50 can be a semi-transparent and semi-reflective mirror or a semi-transparent and semi-reflective prism, as long as it performs the above-mentioned functions, no specific restrictions are imposed here.

[0040] The laser light passing through the semi-transparent mirror 50 is incident on the expanding lens group 60.

[0041] The expanding lens group 60 is used to amplify the angle of the laser. Specifically, in... Figure 1 In the lidar shown, the expanding lens group 60 is a single expanding lens. Of course, in other embodiments, the expanding lens group 60 can also be composed of multiple expanding lenses, as long as the expanding lens group 60 can achieve the function of widening the angle. No specific restrictions are made here.

[0042] In one embodiment, the radius of curvature of the side of the expanding lens in the expanding lens group 60 facing the object to be measured is smaller than the radius of curvature of the side facing away from the object to be measured, and both are positive values.

[0043] The laser light reflected back by the object under test passes through the expanding lens group 60 and converges onto the semi-transparent mirror 50. After being reflected by the semi-transparent mirror 50, it is incident on the receiving lens group 40.

[0044] The receiving lens group 40 includes a first receiving lens 41 and a second receiving lens 42. The first receiving lens 41 and the second receiving lens 42 are used to focus the laser light, thereby focusing the laser light onto the photosensitive unit 21 in the laser receiving plate 20.

[0045] In this embodiment, the first transmitting lens 31 and the second receiving lens 42 are identical lenses. It should be noted that "identical lenses" means that all parameters of the two lenses are the same.

[0046] Since the optical elements through which the laser emitted by the laser emitting plate 10 passes to the object under test are the same as those through which the laser returned from the object under test passes to the laser receiving plate 20, i.e., the optical elements in the receiving and emitting paths of the lidar are the same, the optical distortion in the emitting optical path matches the optical distortion in the receiving optical path. The bending and other effects of the optical distortion in the emitting optical path on the laser beam are canceled out by the optical distortion in the receiving optical path, thereby reducing the influence of optical distortion on the amplitude and other aspects of the received laser beam, and improving the ranging accuracy and range measurement capability of the lidar.

[0047] To further reduce the impact of inherent optical distortions in the optical system on the amplitude and other aspects of the received laser beam, and to improve the ranging accuracy of the lidar, the size of the lidar's emitting and sensing areas can be matched. Specifically, for example... Figure 2 As shown, at least one of the light-emitting units 11 forms a light-emitting region 12 on the laser emitting plate 10, and the light-emitting region 12 is... Figure 2 The area enclosed by the dashed box on the left side is shown. At least one of the photosensitive units 21 forms a photosensitive area 22 on the laser receiving plate 20, and the photosensitive area 22 is... Figure 2The area enclosed by the dashed box on the right side is shown; wherein the light-emitting area 12 and the photosensitive area 22 have the same size in the vertical direction and their tops are aligned, and the vertical direction is parallel to the rotation axis of the lidar.

[0048] For example, such as Figure 2 As shown, the laser emitting plate 10 has multiple rows of light-emitting units 11, and the laser receiving plate 20 has multiple rows of photosensitive units 21. The light-emitting area 12 and the photosensitive area 22 have the same size in the vertical direction. The number of rows of light-emitting units 11 on the laser emitting plate 10 is set to be the same as the number of rows of photosensitive units 21 on the laser receiving plate 20, and the height of the first row of light-emitting units 11 is the same as that of the first row of photosensitive units 21, that is, the top of the first row of light-emitting units 11 is aligned with the top of the first row of photosensitive units 21. This allows for a better match in the arrangement of the light-emitting unit 11 in the laser emitting plate 10 and the photosensitive unit 21 in the laser receiving plate 20, thereby improving the matching of optical distortion between the transmitting and receiving optical systems. Furthermore, since the optical elements in the receiving and transmitting paths are identical, the transmitting and receiving optical systems of the lidar are the same, and their optical distortions are matched. The optical distortion of the receiving optical system can offset the influence of the transmitting optical system's optical distortion on the laser beam. Consequently, the laser beam received by the laser receiving plate 20 has the same arrangement as the laser beam emitted by the laser emitting plate 10, and the amplitude of the laser beam received by the laser receiving plate 20 is further increased, thereby improving the ranging accuracy of the lidar.

[0049] In one embodiment, the light-emitting area 12 and the photosensitive area 22 may be further configured to have the same size in the horizontal direction, wherein the horizontal direction is perpendicular to the rotation axis of the lidar. This can further reduce the influence of optical distortion on the received laser beam in terms of amplitude, etc. Of course, in other embodiments, the light-emitting area 12 and the photosensitive area 22 may not have the same size in the horizontal direction; for example, the size of the photosensitive area 22 in the horizontal direction may be larger than the size of the light-emitting area 12 in the horizontal direction.

[0050] exist Figure 1The lidar shown can achieve a 120° pitch field of view, which can range from -60° to 60°. While possessing a large pitch field of view, by setting the first emitting lens 31 and the second receiving lens 42 to be identical lenses, the optical elements through which the laser emitted by the laser emitting plate 10 reaches the object under test are the same as those through which the laser reflected back from the object under test reaches the laser receiving plate 20. That is, the optical elements on the receiving and emitting paths are identical, thereby reducing the influence of optical distortion on the amplitude and other aspects of the received laser beam, and improving the ranging accuracy and range capability of the lidar.

[0051] Please see Figures 3 to 5 , Figure 3 This is a schematic diagram of the lidar structure in another embodiment of this application. Figure 4 for Figure 3 The diagram shown is a cross-sectional view of a lidar. Figure 5 for Figure 3 The diagram shows the optical structure of a lidar. The lidar 100 includes: a laser emitting plate 10, a laser receiving plate 20, a emitting lens group 30, a receiving lens group 40, a semi-transparent mirror 50, a wide-angle lens group 60, and a reflector 70.

[0052] The laser emitting plate 10 includes at least one light-emitting unit for emitting laser light.

[0053] The laser receiver plate 20 includes at least one photosensitive unit for receiving the returned laser light.

[0054] The emitting lens group 30 includes a first emitting lens 31 and a second emitting lens 32. The emitting lens group 30 is used to collimate the laser.

[0055] The semi-transparent and semi-reflective mirror 50 allows 50% of the laser light to pass through and 50% to be reflected. The laser light passing through the semi-transparent and semi-reflective mirror 50 is then incident on the reflector 70.

[0056] The reflector 70 is tilted at an angle α relative to the vertical direction (e.g., ...). Figure 4 As shown in the figure, the vertical direction is parallel to the rotation axis of the lidar 100.

[0057] In one embodiment, to make the internal layout of the lidar 100 more compact and reduce its size, the reflector 70 can be positioned at the aperture of the emitting lens group 30. Specifically, the aperture is optimally positioned at the edge of the rotating stage of the lidar 100. Figure 3 and Figure 4 As shown.

[0058] It should be noted that in the above embodiment, the aperture of the emitting lens group 30 is a simulated aperture. Placing the reflector 70 at the aperture can save space. Of course, in other embodiments, the aperture of the emitting lens group 30 can also be a physical aperture, and the reflector 70 is placed near the aperture.

[0059] The reflector 70 reflects the laser light that passes through the semi-transparent mirror 50 onto the expansion mirror assembly 60.

[0060] The expanding lens group 60 is tilted at an angle of 2α relative to the vertical direction to expand the angle of the laser.

[0061] In one embodiment, the expanding lens assembly 60 includes at least one expanding lens, and the refractive index relationship between the expanding lens, the first emitting lens 31, and the second emitting lens 32 satisfies the following equation:

[0062] n1 = n2, n2 > n3

[0063] Wherein, n1, n2 and n3 are the refractive indices of the first emitting lens 31, the second emitting lens 32 and the expanding lens, respectively.

[0064] The laser light reflected back by the object under test passes through the expanding lens group 60 and converges on the reflecting mirror 70, and then enters the receiving lens group 40 through the reflection of the reflecting mirror 70 and the semi-transparent and semi-reflective mirror 50 in sequence.

[0065] The receiving lens group 40 includes a first receiving lens 41 and a second receiving lens 42. The first transmitting lens 31 and the second receiving lens 42 are identical lenses, and the second transmitting lens 32 and the first receiving lens 41 are identical lenses.

[0066] Since the optical elements through which the laser emitted by the laser emitting plate 10 passes to the object under test are the same as those through which the laser reflected back from the object under test passes to the laser receiving plate 20, the influence of optical distortion on the received laser beam in terms of amplitude and other aspects is weakened, thereby improving the ranging accuracy and range measurement capability of the lidar.

[0067] To further reduce the impact of optical distortion on the received laser beam in terms of amplitude and other aspects, and improve the ranging accuracy of the lidar, the size of the emitting and photosensitive areas of the lidar can be matched to further improve the matching degree of optical distortion between the transmitting and receiving optical systems. For example, at least one emitting unit forms an emitting area on the laser emitting plate 10, and at least one photosensitive unit forms a photosensitive area on the laser receiving plate 20. The emitting and photosensitive areas have the same size in the vertical direction, and their tops are aligned. Alternatively, the emitting and photosensitive areas can be further made to have the same size in the horizontal direction, thereby further reducing the impact of optical distortion on the laser beam.

[0068] In one embodiment, when the angle α of the reflector 70 relative to the vertical direction is set to 15°, the expansion lens group 60 is tilted at 30° relative to the vertical direction, and the pitch field of view of the lidar 100 can be from -30° to 90°.

[0069] The following is a specific implementation to achieve the above-mentioned pitch field of view of -30° to 90°. In this specific implementation, the α angle is set to 15°. Figures 3 to 5 The specific parameter settings for the first emitting lens 31, the second emitting lens 32, and the expanding lens are shown in Table 1 below:

[0070] Table 1:

[0071]

[0072] In Table 1, G1S1 represents the incident surface of the first emitting lens 31, and G1S2 represents the exit surface of the first emitting lens 31; G2S1 represents the incident surface of the second emitting lens 32, and G2S2 represents the exit surface of the second emitting lens 32; G3S1 represents the side of the expanding mirror facing the reflecting mirror 70, and G3S2 represents the side of the expanding mirror facing the object to be measured; the incident surface of the first receiving lens 41 (i.e., the side facing the semi-transparent and semi-reflective mirror 50) and the exit surface of the second emitting lens 32 are the same curved surface; the exit surface of the first receiving lens 41 (i.e., the side facing the second receiving lens 42) and the incident surface of the second emitting lens 32 are the same curved surface; the incident surface of the second receiving lens 42 (i.e., the side facing the first receiving lens 41) and the exit surface of the first emitting lens 31 are the same curved surface; the exit surface of the second receiving lens 42 (i.e., the side facing the laser receiving plate 20) and the incident surface of the first emitting lens 31 are the same curved surface.

[0073] In addition, the first emitting lens 31 and the second emitting lens 32 are made of flint glass, specifically H-ZLAF92, with a refractive index of 2.003 and an Abbe number of 28.3. The expanding lens is made of optical glass, specifically D-K9, with a refractive index of 1.516 and an Abbe number of 64.05. The thicknesses of the first emitting lens 31, the second emitting lens 32, and the expanding lens are 3.039 mm, 2.719 mm, and 2.520 mm, respectively. The air gap between the first emitting lens 31 and the second emitting lens 32 is 1.889 cm, the air distance between the second emitting lens 32 and the reflector 70 is 5 cm, and the air distance between the reflector 70 and the expanding lens is 5 cm.

[0074] With the parameters set as described above, the lidar 100 has a pitch field of view ranging from -30° to 90°. When the rotary motor in the lidar 100 rotates, it can form a field of view as shown in the image. Figure 6 The field of view is shown.

[0075] It should be noted that the parameters in the above specific embodiments, such as the thickness of each lens and the air gap between lenses, can be designed according to actual needs and are not limited to the specific values ​​mentioned above. The specific values ​​of the above parameters are merely an example.

[0076] In addition, information such as the structure, parameters, and working principle of certain components and regions in this embodiment can be found in the aforementioned embodiments. For the sake of brevity, these details will not be repeated in this embodiment.

[0077] In summary, the lidar 100 in this embodiment not only has a large pitch field of view, but also reduces the influence of optical distortion on the amplitude of the received laser beam, thereby improving the ranging accuracy and range measurement capability of the lidar. At the same time, since the lidar 100 can achieve a large pitch field of view without tilting the body, the size of the lidar 100 is smaller, which better meets the requirements of miniaturization.

[0078] The foregoing disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure, the components and arrangements of specific examples are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application are within the scope of protection claimed by this application.

[0079] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

Claims

1. A lidar, characterized in that, The lidar includes: A laser emitting plate, the laser emitting plate including at least one light-emitting unit, the light-emitting unit being used to emit laser light; A laser receiver plate, the laser receiver plate including at least one photosensitive unit; The emitting lens group includes a first emitting lens and a second emitting lens; The receiving lens group includes a first receiving lens and a second receiving lens; wherein the first transmitting lens and the second receiving lens are the same lens, and the second transmitting lens and the first receiving lens are the same lens; Semi-transparent and semi-reflective mirror and wide-angle lens assembly; The laser beam is collimated by the first emitting lens and the second emitting lens in sequence, and then directed toward the semi-transparent mirror. The laser beam passing through the semi-transparent mirror is amplified by the expanding lens group and then directed toward the object under test. The laser beam reflected back by the object under test is focused onto the semi-transparent mirror through the expanding lens group, and then reflected by the semi-transparent mirror to the first receiving lens. After being focused by the first receiving lens and the second receiving lens, the laser beam is incident on at least one of the photosensitive units. At least one of the light-emitting units forms a light-emitting area on the laser emitting plate, and at least one of the photosensitive units forms a photosensitive area on the laser receiving plate; wherein the light-emitting area and the photosensitive area have the same size in the vertical direction and their tops are aligned, and the vertical direction is parallel to the rotation axis of the lidar.

2. The lidar according to claim 1, characterized in that, The photosensitive area has a horizontal dimension that is greater than or equal to the light-emitting area in the horizontal direction, wherein the horizontal direction is perpendicular to the rotation axis of the lidar.

3. The lidar according to claim 1, characterized in that, The lidar also includes: A reflector is used to reflect the laser light passing through the semi-transparent mirror onto the expanding lens group. The reflector is tilted at an angle α relative to the vertical direction, and the expanding lens group is tilted at an angle 2α relative to the vertical direction. The vertical direction is parallel to the rotation axis of the lidar.

4. The lidar according to claim 3, characterized in that, The reflector is positioned at the aperture of the emitting lens group, and the aperture is optimally positioned at the edge of the lidar's rotating stage.

5. The lidar according to claim 3, characterized in that, α=15°。 6. The lidar according to claim 5, characterized in that, When the expanding lens group is tilted at an angle of 2α relative to the vertical direction, the pitch field of view of the lidar is -30° to 90°.

7. The lidar according to claim 6, characterized in that, The expanding lens assembly includes at least one expanding lens, and the refractive index relationship between the expanding lens, the first emitting lens, and the second emitting lens satisfies the following equation: Wherein, n1, n2, and n3 are the refractive indices of the first emitting lens, the second emitting lens, and the expanding lens, respectively.

8. The lidar according to claim 1, characterized in that, The radius of curvature of the incident surface of the first emitting lens is smaller than the radius of curvature of the exit surface of the first emitting lens, and both are negative values; the radius of curvature of the incident surface of the second emitting lens is positive, and the radius of curvature of the exit surface of the second emitting lens is negative; the expanding lens group includes at least one expanding lens, wherein the radius of curvature of the side of the expanding lens facing the object to be measured is smaller than the radius of curvature of the side facing away from the object to be measured, and both are positive values.

9. The lidar according to claim 1, characterized in that, The semi-transparent mirror includes a semi-transparent mirror sheet or a semi-transparent prism.

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