Laser emission module and laser radar

Abstract

According to the laser emission module and the laser radar provided by the embodiment of the invention, the micro cylindrical lens array is arranged on the laser beam optical path of the laser, each micro cylindrical lens in the micro cylindrical lens array corresponds to one emission channel in the laser, and the micro cylindrical lens is a convex cylindrical surface, so that the laser emission efficiency is improved; the curvature direction of the micro cylindrical lens array is the same as the slow axis direction of the laser beam, so that the micro cylindrical lens array has positive focal power in the slow axis direction and can be homogenized and collimated in the slow axis direction, and then the laser beam passes through the first cylindrical lens of which the curvature direction is the same as the slow axis direction and the first cylindrical lens has positive focal power in the slow axis direction so as to be collimated in the slow axis direction; therefore, linear light spots which are uniformly distributed within a certain angle range in the slow axis direction are realized, the measuring range and the reflectivity consistency of different view fields of the laser radar are improved, the number of optical lenses is reduced, and the installation and adjustment difficulty and cost of an emission lens are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ranging, and in particular to a laser emission module and a laser radar.

[0002] This application is funded by the National Key R&D Program of China, project number: 2023YFB321110X. Background Art

[0003] The principle of laser radar is that the radar emits one or more laser beams to the outside world, and realizes the detection function by receiving the laser signal reflected back from the outside world. The laser radar is mainly composed of a transmitting module, a receiving module, a scanning module and a signal processing module. Among them, the transmitting module is used to emit detection lasers, the receiving module is used to receive echo signals, the scanning module is used to expand the radar detection angle, and the signal processing module is used to convert the signals received by the receiving module into environmental information.

[0004] The laser radar's transmitting module includes a transmitting lens and a laser. In order to improve the laser radar's ranging capability, the energy of a single-tube semiconductor laser is far from enough. It is generally required to use an array laser, and a multi-channel edge-emitting laser is commonly used. The transmitting lens is composed of one or more optical lenses, which are used to shape the beam emitted by the laser into the required line spot.

[0005] The existing laser radar transmitting lens using multi-channel edge-emitting lasers is difficult to achieve a uniformly distributed line spot in the slow axis direction, which affects the consistency of different field of view ranges and reflectivity. At the same time, the transmitting lens has a large number of lenses, which is complicated to install and adjust, and the cost is high. Summary of the invention

[0006] The purpose of the present invention includes providing a laser transmitting module and a laser radar, which can realize a uniformly distributed linear light spot within a certain angle range in the slow axis direction, improve the range and reflectivity consistency of different fields of view of the laser radar, reduce the number of optical lenses, and reduce the difficulty and cost of installing and adjusting the transmitting lens.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a laser emission module, comprising a laser, and a micro cylindrical lens array and a first cylindrical lens sequentially arranged along a laser beam emission direction of the laser;

[0009] The laser is a multi-channel transmitting laser;

[0010] The curvature direction of the micro-cylindrical lens array is the same as the slow axis direction of the laser beam, and the plane direction is the same as the fast axis direction of the laser beam. Each micro-cylindrical lens is a convex cylindrical surface and corresponds to a channel in the laser.

[0011] The first cylindrical lens is a convex cylindrical lens, the curvature direction of which is the same as the slow axis direction of the laser beam, and the plane direction of which is the same as the fast axis direction of the laser beam.

[0012] In an optional embodiment, the distance between the laser and the micro cylindrical lens array is smaller than the focal length of the micro cylindrical lens array;

[0013] The distance between the micro cylindrical lens array and the first cylindrical lens is greater than the focal length of the first cylindrical lens.

[0014] In an optional embodiment, the magnification of each of the micro cylindrical lenses for one channel in the laser is 1.35.

[0015] In an optional embodiment, after passing through the micro cylindrical lens array and the first cylindrical lens, the angle of the slow axis flat top area of ​​the laser beam is greater than or equal to a preset angle, and the unevenness of the slow axis flat top area is less than or equal to a preset unevenness.

[0016] In an optional embodiment, the preset angle is 1.7°;

[0017] The preset unevenness is 7%;

[0018] After passing through the micro cylindrical lens array and the first cylindrical lens, the slow axis divergence angle of the laser beam is less than or equal to 2°.

[0019] In an optional embodiment, the non-uniformity X of the slow axis flat top region is calculated according to the following formula:

[0020] X={X n -X *| / X *} max ;

[0021] Among them, X n- is the average power within 0.1°, X * It is the average value of n segments, where n is the slow axis flat top angle divided by 0.1.

[0022] In an optional embodiment, the micro cylindrical lens array has a radius of curvature of 1.363 mm and a thickness of 0.5 mm;

[0023] The first cylindrical lens has a curvature radius of 19.307 mm and a thickness of 2 mm.

[0024] In an optional embodiment, a surface of the first cylindrical lens close to the micro cylindrical lens array is a plane.

[0025] In an optional embodiment, the laser emission module also includes a second cylindrical lens located between the first cylindrical lens and the micro cylindrical lens array, the second cylindrical lens is a convex cylindrical lens, the curvature direction of which is the same as the fast axis direction of the laser beam, and the plane direction is the same as the slow axis direction of the laser beam.

[0026] In an optional implementation, the distance between the laser and the second cylindrical lens is greater than the focal length of the second cylindrical lens, and the distance between the first cylindrical lens and the second cylindrical lens is 20.589 mm.

[0027] In an optional embodiment, a surface of the micro cylindrical lens array and the second cylindrical lens close to each other is a plane.

[0028] In an optional implementation, the micro cylindrical lens array and the second cylindrical lens are an integrated structure, a glued structure, or a discrete structure.

[0029] In an optional embodiment, the second cylindrical lens has a radius of curvature of 3.743 mm and a thickness of 10.141 mm;

[0030] After passing through the second cylindrical lens, the fast axis divergence angle of the laser beam is less than or equal to 0.1°.

[0031] In a second aspect, the present invention provides a laser radar, comprising the laser emission module described in any one of the aforementioned embodiments.

[0032] The laser emission module and laser radar provided by the embodiments of the present invention have the following beneficial effects:

[0033] By setting a micro cylindrical lens array on the laser beam optical path of the laser, since each micro cylindrical lens in the micro cylindrical lens array corresponds to an emission channel in the laser, the micro cylindrical lens is a convex cylindrical surface, and the curvature direction of the micro cylindrical lens array is the same as the slow axis direction of the laser beam, it has positive optical focal length in the slow axis direction, can be homogenized and collimated in the slow axis direction, and then passes through a first cylindrical lens with the same curvature direction as the slow axis direction. The first cylindrical lens has positive optical focal length in the slow axis direction to collimate in the slow axis direction, but has no effect in the fast axis direction, thereby achieving a uniformly distributed line spot within a certain angle range in the slow axis direction, thereby improving the range and reflectivity consistency of different fields of view of the laser radar, reducing the number of optical lenses, and reducing the difficulty and cost of assembling the emission lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 This is a schematic diagram of each channel of the laser emitting light;

[0036] Figure 2 for Figure 1 Schematic diagram of slow axis energy distribution in angular space;

[0037] Figure 3 It is a schematic diagram of the structure of the emission module in the slow axis direction;

[0038] Figure 4 It is a schematic diagram of the structure of the transmitting module in the fast axis direction;

[0039] Figure 5 for Figure 4 A magnified schematic diagram of the structure of the micro cylindrical lens array;

[0040] Figure 6 It is a schematic diagram of a magnified virtual image formed by a single channel of a micro cylindrical lens array;

[0041] Figure 7 Schematic diagram of the slow-axis energy distribution in angular space of the output line spot of the transmitting module.

[0042] Icon: S0-laser; S1-micro-convex cylinder; S2-whole plane; S3-second plane; S4-second curved surface; S5-first plane; S6-first curved surface; L1-micro-cylindrical lens array; L2-second cylindrical lens; L3-first cylindrical lens. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0048] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0049] The embodiment of the present application discloses a laser emission module, which is mainly used in laser radar, and of course can also be used in other equipment that requires laser emission.

[0050] The laser emission module includes a laser S0 and a micro cylindrical lens array L1 and a first cylindrical lens L3 arranged in sequence along the laser beam emission direction of the laser S0;

[0051] Laser S0 is a multi-channel transmitting laser S0, for example Figure 1 The angular space slow axis energy distribution of the four-channel edge-emitting laser S0 is shown as Figure 2 As shown, the energies of the various channels are separated from each other.

[0052] Combination Figure 3 and Figure 5 The curvature direction of the micro cylindrical lens array L1 is the same as the slow axis direction of the laser beam, and the plane direction is the same as the fast axis direction of the laser beam. Each micro cylindrical lens is a convex cylindrical surface and corresponds to a channel in the laser S0; the array direction of each corresponding micro cylindrical lens is the same as the slow axis direction of the laser beam.

[0053] The first cylindrical lens L3 is a convex cylindrical lens, the curvature direction of which is the same as the slow axis direction of the laser beam, and the plane direction of which is the same as the fast axis direction of the laser beam.

[0054] In this way, by setting the micro-cylindrical lens array L1 on the laser beam optical path of the laser S0, since each micro-cylindrical lens in the micro-cylindrical lens array L1 corresponds to an emission channel in the laser S0, the micro-cylindrical lens is a convex cylindrical surface, and the curvature direction of the micro-cylindrical lens array L1 is the same as the slow axis direction of the laser beam, so it has positive optical focal length in the slow axis direction, and can be homogenized and collimated in the slow axis direction, and then passes through the first cylindrical lens L3 whose curvature direction is the same as the slow axis direction. The first cylindrical lens L3 has positive optical focal length in the slow axis direction to collimate in the slow axis direction, but has no effect in the fast axis direction, thereby achieving a uniformly distributed linear light spot within a certain angle range in the slow axis direction, thereby improving the range and reflectivity consistency of different fields of view of the laser radar, reducing the number of optical lenses, and reducing the difficulty and cost of assembling the emission lens.

[0055] The distance between the laser S0 and the micro-cylindrical lens array L1 is less than the focal length of the micro-cylindrical lens array L1; thus, the laser beam can be diverged into a virtual image after passing through the micro-cylindrical lens array L1. Figure 6 As shown, the light emitted by each channel is staggered and diverged, and the laser beam emitted by the laser S0 is shaped in the slow axis direction, and the energy distribution in the slow axis direction is more uniform. The distance between the micro cylindrical lens array L1 and the first cylindrical lens L3 is greater than the focal length of the first cylindrical lens L3, which can play a focusing and collimating role to form a linear light spot that is uniformly distributed within a certain angle range in the slow axis direction.

[0056] The side of the first cylindrical lens L3 close to the micro cylindrical lens array L1 is a plane, that is, the side of the first cylindrical lens L3 away from the laser S0 is a first curved surface S6. The first curved surface S6 has no curvature in the fast axis direction and has a curvature in the slow axis direction. The side of the first cylindrical lens L3 close to the laser S0 is a first plane S5, so that the light first passes through the flat first plane S5, and then encounters the first curved surface S6 with curvature. Since the first plane S5 will not change the direction of the light, the light incident on the first cylindrical lens L3 almost maintains the original direction in the slow axis direction before encountering the first curved surface S6, so that the light converges later, so that the line spot has a sufficient length.

[0057] Combination Figure 3 and Figure 4 In this embodiment, the laser emission module also includes a second cylindrical lens L2 located between the first cylindrical lens L3 and the micro cylindrical lens array L1. The second cylindrical lens L2 is a convex cylindrical lens, and its curvature direction is the same as the fast axis direction of the laser beam, and its plane direction is the same as the slow axis direction of the laser beam. Therefore, it has positive optical focal length in the fast axis direction. The laser beam can be collimated in the fast axis direction through the second cylindrical lens L2, and the slow axis direction has no effect.

[0058] In detail, the distance between the laser S0 and the second cylindrical lens L2 is greater than the focal length of the second cylindrical lens L2, so as to focus, converge and collimate the divergence angle of the laser beam in the fast axis direction to improve the brightness of the line spot.

[0059] The side of the micro-cylindrical lens array L1 and the second cylindrical lens L2 close to each other is a plane, that is, the side of the micro-cylindrical lens array L1 close to the laser S0 has a plurality of micro-convex cylindrical surfaces S1, the micro-convex cylindrical surfaces S1 have an arc in the slow axis direction, and have no arc in the fast axis direction. The side of the micro-cylindrical lens array L1 away from the laser S0 is a whole plane S2, the side of the second cylindrical lens L2 close to the laser S0 is a second plane S3, and the side of the second cylindrical lens L2 away from the laser S0 is a second curved surface S4, and the second curved surface S4 is in the fast axis direction. There is an arc segment upward and no arc in the slow axis direction, so that the light emitted from each channel of the laser S0 first passes through the corresponding micro-convex cylindrical surface S1 for virtual image magnification and shaping to ensure the uniformity of the line spot in the slow axis direction, and then passes through the flat plane S2 and the second plane S3. The plane will not change the direction of the light, so the light incident on the second cylindrical lens L2 almost maintains the original direction in the fast axis direction before encountering the second curved surface S4, so that the light converges later, so that the line spot has a certain size in the width direction.

[0060] Among them, the micro cylindrical lens array L1 and the second cylindrical lens L2 are an integrated structure, a glued structure or a discrete structure, and there is no specific limitation. For example, in this embodiment, the micro cylindrical lens array L1 and the second cylindrical lens L2 are set to an integrated structure or glued structure to further reduce the number of lenses, thereby reducing the difficulty and cost of assembly and adjustment. The so-called discrete structure means that there is a gap between the micro cylindrical lens array L1 and the second cylindrical lens L2.

[0061] The micro cylindrical lens array L1, the first cylindrical lens L3 and the second cylindrical lens L2 may be made of the same material or different materials. When the micro cylindrical lens array L1 and the second cylindrical lens L2 are an integrated structure, the two are made of the same material.

[0062] For example, in this embodiment, the micro cylindrical lens array L1, the first cylindrical lens L3 and the second cylindrical lens L2 are made of the same material, and the refractive index of the material is 1.5168 and the Abbe number is 64.199.

[0063] It should be noted that the so-called curvature direction is the focal axis of the cylindrical lens, which is the side of the cylindrical lens with curvature, which determines the behavior of light in this direction. When light passes through the cylindrical lens, they will be refracted, focused or collimated in the curvature direction. The plane direction is the non-focusing axis, which is the flat side of the cylindrical lens, that is, the direction without curvature. In this direction, the cylindrical lens will not change the propagation path of light.

[0064] The slow axis flat top area of ​​the laser beam is the area where the intensity of the laser beam is evenly distributed in the slow axis direction, and the non-uniformity of the slow axis flat top area is the non-uniformity of the light intensity distribution of the laser beam in the slow axis direction. After passing through the micro cylindrical lens array L1 and the first cylindrical lens L3, the angle of the slow axis flat top area of ​​the laser beam is greater than or equal to the preset angle, that is, the angle of the slow axis flat top area of ​​the line spot formed after passing through the first cylindrical lens L3 is greater than or equal to the preset angle, and the non-uniformity of the slow axis flat top area is less than or equal to the preset non-uniformity, so that the energy distribution of the line spot is uniform, such as Figure 7 As shown, the range and reflectivity consistency of the lidar in different fields of view are guaranteed.

[0065] The non-uniformity X of the slow axis flat top region is calculated according to the following formula (1):

[0066] X={X n -X *| / X *} max ; (1)

[0067] Among them, X n- is the average power within 0.1°, X * It is the average value of n segments, where n is the slow axis flat top angle divided by 0.1.

[0068] In this embodiment, the radius of curvature of the micro cylindrical lens array L1 is 1.363 mm and the thickness is 0.5 mm. The radius of curvature of the first cylindrical lens L3 is 19.307 mm and the thickness is 2 mm. The radius of curvature of the second cylindrical lens L2 is 3.743 mm and the thickness is 10.141 mm; the distance between the first cylindrical lens L3 and the second cylindrical lens L2 is 20.589 mm. The magnification of each micro cylindrical lens for one channel in the laser S0 is 1.35.

[0069] The preset angle is 1.7°, and the preset unevenness is 7%; that is, the slow axis flat top angle of the laser beam (line spot) after passing through the micro cylindrical lens array L1 and the first cylindrical lens L3 is greater than or equal to 1.7°, and the flat top angle satisfies that the unevenness X is less than or equal to 7%.

[0070] After passing through the micro-cylindrical lens array L1 and the first cylindrical lens L3, the slow axis divergence angle of the laser beam (line spot) is less than or equal to 2°. In this way, the difference between the slow axis flat zone angle and the slow axis divergence angle is less than or equal to 0.3°. The closeness of the slow axis divergence angle and the flat top zone angle can make the edge of the uniformly distributed line spot sharp. After passing through the second cylindrical lens L2, the fast axis divergence angle of the laser beam (line spot) is less than or equal to 0.1°. A smaller fast axis divergence angle can increase the energy density of the beam.

[0071] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A laser emission module, characterized in that: It comprises a laser (S0) and a micro cylindrical lens array (L1) and a first cylindrical lens (L3) arranged in sequence along the direction in which the laser beam of the laser (S0) is emitted; The laser (S0) is a multi-channel transmitting laser (S0); The curvature direction of the micro-cylindrical lens array (L1) is the same as the slow axis direction of the laser beam, and the plane direction is the same as the fast axis direction of the laser beam. Each micro-cylindrical lens is a convex cylindrical surface and corresponds to a channel in the laser (S0); The first cylindrical lens (L3) is a convex cylindrical lens, the curvature direction of which is the same as the slow axis direction of the laser beam, and the plane direction of which is the same as the fast axis direction of the laser beam.

2. The laser emission module according to claim 1, characterized in that: The distance between the laser (S0) and the micro cylindrical lens array (L1) is smaller than the focal length of the micro cylindrical lens array (L1); The distance between the micro cylindrical lens array (L1) and the first cylindrical lens (L3) is greater than the focal length of the first cylindrical lens (L3).

3. The laser emission module according to claim 2, characterized in that: The magnification of each micro cylindrical lens for one channel in the laser (S0) is 1.

35.

4. The laser emission module according to claim 1, characterized in that: After passing through the micro cylindrical lens array (L1) and the first cylindrical lens (L3), the angle of the slow axis flat top area of ​​the laser beam is greater than or equal to a preset angle, and the unevenness of the slow axis flat top area is less than or equal to a preset unevenness.

5. The laser emission module according to claim 4, characterized in that: The preset angle is 1.7°; The preset unevenness is 7%; After passing through the micro cylindrical lens array (L1) and the first cylindrical lens (L3), the slow axis divergence angle of the laser beam is less than or equal to 2°.

6. The laser emission module according to claim 5, characterized in that: The non-uniformity X of the slow axis flat top area is calculated according to the following formula: X={X n -X * | / X * } max ; Among them, X n- is the average power within 0.1°, X * It is the average value of n segments, where n is the slow axis flat top angle divided by 0.

1.

7. The laser emission module according to any one of claims 1 to 6, characterized in that: The micro cylindrical lens array (L1) has a curvature radius of 1.363 mm and a thickness of 0.5 mm; the first cylindrical lens (L3) has a curvature radius of 19.307 mm and a thickness of 2 mm; and / or, A surface of the first cylindrical lens (L3) close to the micro cylindrical lens array (L1) is a plane.

8. The laser emission module according to claim 1, characterized in that: The laser emission module also includes a second cylindrical lens (L2) located between the first cylindrical lens (L3) and the micro cylindrical lens array (L1), wherein the second cylindrical lens (L2) is a convex cylindrical lens, a curvature direction of which is the same as the fast axis direction of the laser beam, and a plane direction of which is the same as the slow axis direction of the laser beam.

9. The laser emission module according to claim 8, characterized in that: The distance between the laser (S0) and the second cylindrical lens (L2) is greater than the focal length of the second cylindrical lens (L2), and the distance between the first cylindrical lens (L3) and the second cylindrical lens (L2) is 20.589 mm; and / or, The surfaces of the micro cylindrical lens array (L1) and the second cylindrical lens (L2) close to each other are flat surfaces; and / or, The micro cylindrical lens array (L1) and the second cylindrical lens (L2) are an integrated structure, a glued structure or a separate structure; and / or, The curvature radius of the second cylindrical lens (L2) is 3.743 mm and the thickness is 10.141 mm; after passing through the second cylindrical lens (L2), the fast axis divergence angle of the laser beam is less than or equal to 0.1°.

10. A laser radar, characterized in that: A laser emission module comprising any one of claims 1-9.

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