Lidar

Abstract

This application provides a lidar, comprising a laser emitting plate, a laser receiving plate, a semi-transparent mirror, a lens group, and a wide-angle lens group. The laser emitting plate includes at least one emitting unit, which forms a emitting area on the laser emitting plate. The laser receiving plate includes at least one photosensitive unit, which forms a photosensitive area on the laser receiving plate. The emitting area and the photosensitive area are the same size in the vertical direction, and their tops are aligned. This lidar can achieve a large elevation field of view. Furthermore, the emitting and receiving optical systems of this lidar are identical, effectively reducing the impact of optical distortion on the amplitude and other aspects of the received laser beam, thus 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 at least one light-emitting unit forming a light-emitting area on the laser emitting plate, the light-emitting unit being used to emit laser light;

[0007] A laser receiving plate includes at least one photosensitive unit, and the at least one photosensitive unit 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 the tops of the light-emitting area and the photosensitive area are aligned, and the vertical direction is parallel to the rotation axis of the lidar;

[0008] Semi-transparent mirror, lens group and expanding lens group;

[0009] The laser beam passes through the semi-transparent mirror and is incident on the lens group. After being collimated by the lens group, it is incident on the expanding lens group and then amplified by the expanding lens group before being directed toward the object under test. The laser beam reflected back by the object under test passes through the expanding lens group and the lens group in sequence and converges to the semi-transparent mirror. It is then reflected by the semi-transparent mirror to the photosensitive unit.

[0010] In one embodiment, the lidar further includes a triangular prism, wherein the expanding lens group is tilted at an angle α relative to the vertical direction, and the laser beam collimated by the lens group is incident on the triangular prism and totally reflected by the triangular prism onto the expanding lens group.

[0011] In one embodiment, the triangular prism is disposed at a preset position of the lidar, such that the laser beam parallel to the optical axis of the lens group is totally reflected by the triangular prism and then incident on the expansion lens group parallel to the optical axis of the expansion lens group.

[0012] In one embodiment, α = 30°.

[0013] In one embodiment, when the expanding lens group is tilted at an angle α relative to the vertical direction, the pitch field of view of the lidar is -30° to 90°.

[0014] 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.

[0015] In one embodiment, the expanding lens group includes a first expanding lens and a second expanding lens. The laser, after being collimated by the lens group, is expanded in angle by passing through the first expanding lens and the second expanding lens in sequence before being directed toward the object to be tested.

[0016] In one embodiment, the radius of curvature of the surface of the first expanding lens facing the lens group is smaller than the radius of curvature of the surface facing the second expanding lens, and both are positive values; the radius of curvature of the surface of the second expanding lens facing the first expanding lens is smaller than the radius of curvature of the surface facing the object to be measured, and both are positive values.

[0017] In one embodiment, the lens group includes a first lens, a second lens, and a third lens; the laser light passing through the semi-transparent mirror is collimated by the first lens, the second lens, and the third lens in sequence before being directed toward the wide-angle lens group.

[0018] In one embodiment, the radius of curvature of the surface of the first lens facing the semi-transparent mirror is smaller than the radius of curvature of the surface facing the second lens, and both are negative values; the radius of curvature of the surface of the second lens facing the first lens is larger than the radius of curvature of the surface facing the third lens, and both are negative values; the radius of curvature of the surface of the third lens facing the second lens is negative, and the radius of curvature of the surface of the third lens facing the expanding lens group is positive.

[0019] This application provides a lidar that achieves a large pitch field of view through a semi-transparent mirror, a lens group, and an expansion lens group. Furthermore, in this lidar, the emitting area and the photosensitive area have the same vertical dimensions and their tops are aligned. The optical elements through which the emitted laser travels to the object under test are the same as those through which the returning laser travels to the laser receiving plate. This makes the emitting and receiving optical systems of the lidar identical. Consequently, the optical distortion of the emitting optical system is the same as that of the receiving optical system. The bending and other effects of the emitting optical system's optical distortion on the laser beam are thus canceled out by the receiving optical system's optical distortion, reducing the impact of optical distortion on the amplitude and other aspects of the received laser beam, thereby improving the lidar's ranging accuracy and range capability. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the structure of a lidar in one embodiment of this application;

[0022] Figure 2 for Figure 1 The diagram shows a cross-sectional structure of a lidar.

[0023] Figure 3 for Figure 1 The diagram shows the structure of the laser transmitter and laser receiver in a lidar system.

[0024] Figure 4 This is a schematic diagram of the lidar structure in another embodiment of this application;

[0025] Figure 5 for Figure 4 The diagram shows a cross-sectional structure of a lidar.

[0026] Figure 6 for Figure 4 The diagram shows the field of view of the lidar.

[0027] 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

[0028] 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.

[0029] 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.

[0030] Please refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the structure of a lidar in one embodiment of this application; Figure 2 for Figure 1 The diagram shows a cross-sectional structure of a lidar. Figure 3 for Figure 1 The diagram shows the structure of the laser emitting plate and laser receiving plate in the lidar. The lidar 100 includes a laser emitting plate 10, a laser receiving plate 20, a semi-transparent mirror 30, a lens group 40, and an expansion lens group 50.

[0031] The laser emitting plate 10 includes at least one light-emitting unit 11, which is used to emit laser light. At least one light-emitting unit 11 forms a light-emitting region 12 on the laser emitting plate 10, and the light-emitting region 12 is... Figure 3 The area enclosed by the dashed box on the left is shown.

[0032] The laser receiving plate 20 includes at least one photosensitive unit 21 for receiving the returned laser light. The at least one photosensitive unit 21 forms a photosensitive area 22 on the laser receiving plate 20. The photosensitive area 22 is... Figure 3 The 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 100.

[0033] For example, such as Figure 3As 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 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 the height 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 makes the arrangement of the light-emitting units 11 in the laser emitting plate 10 and the photosensitive units 21 in the laser receiving plate 20 more matched, thereby making the optical distortion of the transmitting optical system and the optical distortion of the receiving optical system more matched, which is more conducive to the receiving optical system reducing the influence of the optical distortion of the transmitting optical system on the laser beam.

[0034] In one embodiment, the light-emitting area 12 and the photosensitive area 22 can 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 ensures that the light-emitting unit 11 in the laser emitting plate 10 and the photosensitive unit 21 in the laser receiving plate 20 are matched in both the longitudinal and transverse directions, thereby further matching the optical distortion of the emitting optical system and the receiving optical system.

[0035] Of course, in other embodiments, the dimensions of the light-emitting area 12 and the photosensitive area 22 in the horizontal direction may also be different. For example, the dimension of the photosensitive area 22 in the horizontal direction is larger than the dimension of the light-emitting area 12 in the horizontal direction.

[0036] The laser emitted by the light-emitting unit 11 is incident on the semi-transparent and semi-reflective mirror 30. The semi-transparent and semi-reflective mirror 30 allows 50% of the laser to be transmitted and 50% to be reflected. The semi-transparent and semi-reflective mirror 30 can be a semi-transparent and semi-reflective sheet or a semi-transparent and semi-reflective prism, as long as it performs the above-mentioned functions, no specific limitation is made here.

[0037] The laser beam passes through the semi-transparent mirror 30 and is incident on the lens group 40. The lens group 40 is used to collimate the laser beam.

[0038] like Figure 1 As shown, the lens group 40 includes a first lens 41, a second lens 42, and a third lens 43. The laser light passing through the semi-transparent mirror 30 is collimated by the first lens 41, the second lens 42, and the third lens 43 in sequence before being directed towards the wide-angle lens group 50.

[0039] In one embodiment, the radius of curvature of the surface of the first lens 41 facing the semi-transparent mirror 30 is smaller than the radius of curvature of the surface facing the second lens 42, and both are negative values; the radius of curvature of the surface of the second lens 42 facing the first lens 41 is larger than the radius of curvature of the surface facing the third lens 43, and both are negative values; the radius of curvature of the surface of the third lens 43 facing the second lens 42 is negative, and the radius of curvature of the surface of the third lens 43 facing the expanding lens group 50 is positive.

[0040] After collimation, the laser beam is incident on the expanding lens group 50, which is used to expand the angle of the laser beam.

[0041] like Figure 1 As shown, the expanding lens group 50 includes a first expanding lens 51 and a second expanding lens 52. After being collimated by the lens group 40, the laser beam is expanded in angle by passing through the first expanding lens 51 and the second expanding lens 52 in sequence before being directed toward the object to be measured.

[0042] In one embodiment, the radius of curvature of the surface of the first expanding lens 51 facing the lens group 40 is smaller than the radius of curvature of the surface facing the second expanding lens 52, and both are positive values; the radius of curvature of the surface of the second expanding lens 52 facing the first expanding lens 51 is smaller than the radius of curvature of the surface facing the object to be measured, and both are positive values.

[0043] It should be noted that, in Figure 1 In the lidar 100 shown, the expanding lens group 50 includes two expanding lenses. In other embodiments, the expanding lens group 50 may include one or more expanding lenses, as long as the preset expanding function can be achieved.

[0044] The laser light reflected back by the object under test passes sequentially through the expansion lens group 50 and the lens group 40 and converges to the semi-transparent mirror 30, and is reflected by the semi-transparent mirror 30 to the photosensitive unit 21.

[0045] By setting appropriate optical parameters, it is possible to achieve Figure 1 The lidar 100 shown has a 120° pitch field of view, which can range from -60° to 60°.

[0046] Since the emitting area 12 and the photosensitive area 22 have the same vertical dimensions and their tops are aligned, 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. That is, the emitting optical system and the receiving optical system of the lidar 100 are the same optical system. In this way, the optical distortion of the emitting optical system is the same as that of the receiving optical system. The bending and other effects of the optical distortion of the emitting optical system on the laser beam will be canceled out by the optical distortion of the receiving optical system. This makes the laser beam received by the laser receiving plate 20 have the same arrangement as the laser beam emitted by the laser emitting plate 10, 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 100.

[0047] In this embodiment, the lidar 100 not only has a large pitch field of view, but also effectively reduces the influence of optical distortion on the received laser beam, thereby improving the ranging accuracy and range measurement capability of the lidar 100.

[0048] Please see Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the lidar structure in another embodiment of this application. Figure 5 for Figure 4 The diagram shows a cross-sectional structure of a lidar. The lidar 100 includes: a laser emitting plate 10, a laser receiving plate 20, a semi-transparent mirror 30, a lens group 40, an expanding lens group 50, and a triangular prism 60.

[0049] The laser emitting plate 10 includes at least one light-emitting unit for emitting laser light. At least one of the light-emitting units forms a light-emitting area on the laser emitting plate 10.

[0050] The laser receiver plate 20 includes at least one photosensitive unit for receiving returned laser light. At least one photosensitive unit forms a photosensitive area on the laser receiver plate 20; wherein the emitting area and the photosensitive area are the same size in the vertical direction and their tops are aligned, the vertical direction being parallel to the rotation axis of the lidar 100.

[0051] In this embodiment, the horizontal dimension of the photosensitive area is equal to the horizontal dimension of the light-emitting area. This allows for a better match in the arrangement of the light-emitting units in the laser emitting plate 10 and the photosensitive units in the laser receiving plate 20. This also allows for a better match between the optical distortion of the emitting optical system and the receiving optical system of the lidar 100, which helps the receiving optical system reduce the impact of the optical distortion of the emitting optical system on the laser beam.

[0052] Of course, in other embodiments, the dimensions of the light-emitting area and the photosensitive area in the horizontal direction may also be different. For example, the dimension of the photosensitive area in the horizontal direction may be larger than the dimension of the light-emitting area in the horizontal direction.

[0053] The laser emitted by the light-emitting unit passes through the semi-transparent mirror 30 and is directed towards the lens group 40. The lens group 40 is used to collimate the laser. The lens group 40 includes a first lens 41, a second lens 42, and a third lens 43. The laser light passing through the semi-transparent mirror 30 is collimated by the first lens 41, the second lens 42, and the third lens 43 in sequence before being directed towards the triangular prism 60. After total internal reflection by the triangular prism 60, it is directed onto the expanding lens group 50. After the angle is amplified by the expanding lens group 50, it is directed towards the object to be measured.

[0054] like Figure 5 As shown, the wide-angle lens assembly 50 is tilted at an angle α relative to the vertical direction. The wide-angle lens assembly 50 includes a first wide-angle lens 51 and a second wide-angle lens 52. Both the first wide-angle lens 51 and the second wide-angle lens 52 are tilted at an angle α relative to the vertical direction.

[0055] Because of the tilted setting of the expansion lens group 50, the optical axis of the expansion lens group 50 is no longer the same as that of the lens group 40. Therefore, the triangular prism 60 can be set at a preset position of the lidar 100 so that the laser parallel to the optical axis of the lens group 40 is totally reflected by the triangular prism 60 and then incident on the expansion lens group 50 parallel to the optical axis of the expansion lens group 50.

[0056] The laser light reflected back by the object under test passes sequentially through the expanding lens group 50, the triangular prism 60 and the lens group 40 and converges to the semi-transparent mirror 30, and is reflected by the semi-transparent mirror 30 to the photosensitive unit.

[0057] Since the emitting area and the photosensitive area have the same vertical dimensions and their tops are aligned, and the optical elements through which the emitted laser passes to the object under test are the same as those through which the returning laser passes to the laser receiving plate 20, that is, the emitting optical system and the receiving optical system of the lidar 100 are the same optical system, the effects of optical distortion of the emitting optical system on the bending of the laser beam are canceled out by the optical distortion of the receiving optical system. This reduces the influence of optical distortion on the received laser beam and improves the ranging accuracy and range measurement capability of the lidar.

[0058] Meanwhile, the lidar 100 only needs to tilt the expander lens group 50 by an angle α, and align the optical axis of the expander lens group 50 with the optical axis of the lens group 40 through the total internal reflection of the triangular prism 60, to achieve an asymmetrical large pitch field of view. For example, by setting the tilt angle α to 30°, the pitch field of view range of the lidar 100 can be from -30° to 90°. In this way, a large pitch field of view can be achieved without tilting the fuselage, making the lidar 100 smaller and better meeting the requirements of miniaturization.

[0059] The following is a specific implementation method to achieve the aforementioned pitch field of view of -30° to 90°. In this specific implementation method, the α angle is set to 30°. The specific parameters of each lens are shown in Table 1 below:

[0060] Table 1:

[0061]

[0062]

[0063] In Table 1, G1S1 represents the surface of the first lens 41 facing the semi-transparent mirror 30, G1S2 represents the surface of the first lens 41 facing the second lens 42; G2S1 represents the surface of the second lens 42 facing the first lens 41, G2S2 represents the surface of the second lens 43 facing the third lens 43; G3S1 represents the surface of the third lens 43 facing the second lens 42, G3S2 represents the surface of the third lens 43 facing the expanding lens group 50; G4S1 represents the surface of the first expanding lens 51 facing the lens group 40, G4S2 represents the surface of the first expanding lens 51 facing the second expanding lens 52; G5S1 represents the surface of the second expanding lens 52 facing the first expanding lens 51, G5S2 represents the surface of the second expanding lens 52 facing the object to be measured.

[0064] The first lens 41, the second lens 42, the third lens 43, the first expanding lens 51, and the second expanding lens 52 are made of flint glass, specifically H-ZLAF92, with a refractive index of 2.003 and an Abbe number of 28.3. The air gap between the first lens 41 and the image plane is 12 cm, the air gap between the first lens 41 and the second lens 42 is 1 cm, the air gap between the second lens 42 and the third lens 43 is 1 cm, the air gap between the third lens 43 and the aperture of the lens group 40 is 0.577 cm, the air gap between the first expanding lens 51 and the aperture of the lens group 40 is 20 cm, and the air gap between the first expanding lens 51 and the second expanding lens 52 is 2.99 cm.

[0065] 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. Therefore, Figure 4 The lidar 100 shown can achieve a pitch field of view of -30° to 90° without tilting the body. Compared with devices with tilted bodies, lidar 100 is smaller in size, which is more in line with the requirements of miniaturization. At the same time, its manufacturing cost is also lower.

[0066] 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.

[0067] In addition, the structural and parameter information of certain components and regions in this embodiment can be referred to the aforementioned embodiments, and will not be repeated here for the sake of brevity.

[0068] 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, the lidar 100 is smaller in size than lidars that tilt the fuselage to achieve a large pitch field of view, better meeting the requirements of miniaturization.

[0069] 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.

[0070] 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 at least one light-emitting unit forming a light-emitting area on the laser emitting plate, the light-emitting unit being used to emit laser light; A laser receiving plate includes at least one photosensitive unit, and the at least one photosensitive unit 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 the tops of the light-emitting area and the photosensitive area are aligned, and the vertical direction is parallel to the rotation axis of the lidar; Semi-transparent mirror, lens group and expanding lens group; The laser beam passes through the semi-transparent mirror and is incident on the lens group. After being collimated by the lens group, it is incident on the expanding lens group and then amplified by the expanding lens group before being directed toward the object under test. The laser beam reflected back by the object under test passes through the expanding lens group and the lens group in sequence and converges to the semi-transparent mirror. It is then reflected by the semi-transparent mirror to the photosensitive unit.

2. The lidar according to claim 1, characterized in that, The lidar also includes: A triangular prism is provided, with the expanding lens group tilted at an angle α relative to the vertical direction. The laser, after being collimated by the lens group, is incident on the triangular prism and is totally reflected by the triangular prism onto the expanding lens group.

3. The lidar according to claim 2, characterized in that, The triangular prism is positioned at a preset location on the lidar so that laser light parallel to the optical axis of the lens group is totally reflected by the triangular prism and then incident on the expansion lens group parallel to the optical axis of the expansion lens group.

4. The lidar according to claim 2, characterized in that, α＝30°。 5. The lidar according to claim 4, characterized in that, When the expanding lens group is tilted at an angle α relative to the vertical direction, the pitch field of view of the lidar is -30° to 90°.

6. 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.

7. The lidar according to claim 1, characterized in that, The expanding lens group includes a first expanding lens and a second expanding lens. After being collimated by the lens group, the laser is expanded in angle by passing through the first expanding lens and the second expanding lens in sequence before being directed toward the object to be tested.

8. The lidar according to claim 7, characterized in that, The radius of curvature of the surface of the first expanding lens facing the lens group is smaller than the radius of curvature of the surface facing the second expanding lens, and both are positive values; the radius of curvature of the surface of the second expanding lens facing the first expanding lens is smaller than the radius of curvature of the surface facing the object to be measured, and both are positive values.

9. The lidar according to claim 1, characterized in that, The lens group includes a first lens, a second lens, and a third lens; the laser light passing through the semi-transparent mirror is collimated by the first lens, the second lens, and the third lens in sequence before being directed toward the wide-angle lens group.

10. The lidar according to claim 9, characterized in that, The radius of curvature of the surface of the first lens facing the semi-transparent mirror is smaller than the radius of curvature of the surface facing the second lens, and both are negative values; the radius of curvature of the surface of the second lens facing the first lens is larger than the radius of curvature of the surface facing the third lens, and both are negative values; the radius of curvature of the surface of the third lens facing the second lens is negative, and the radius of curvature of the surface of the third lens facing the expanding lens group is positive.

Images