Test board assembly, diffuse reflection target board, design method and laser radar test method

Abstract

The invention provides a diffuse reflection target plate. The diffuse reflection target plate comprises a substrate; a plurality of microstructures; wherein the plurality of microstructures are distributed on the substrate; the substrate has a first reflectivity, and the microstructure has a second reflectivity; the first reflectivity is different from the second reflectivity; the target reflectivity of the diffuse reflection target plate is related to the first reflectivity and the second reflectivity. According to the diffuse reflection target plate, reliable large-range reflectivity can be achieved, and the test requirement is met. By changing the specification and / or distribution mode of the microstructure, the duty ratio of the substrate can be adjusted, then the target reflectivity of the diffuse reflection target plate is adjusted, the reflectivity range from 0% to 100% is covered, and flexibility and reliability are achieved.

Description

Technical Field

[0001] The present invention generally relates to the field of testing, and in particular to a diffuse reflection target plate, a test plate assembly, a design method for a diffuse reflection target plate, and a test method for a laser radar. Background Art

[0002] When testing the performance of LiDAR point clouds, diffuse reflective target plates with different reflectivity are required. The existing diffuse reflective target plates are mainly made by modulating a coating / paint that meets the reflectivity requirements and evenly applying or spraying it on the substrate. The reflectivity of the diffuse reflective target plate depends on the coating / paint used.

[0003] However, the reflectivity range of diffuse reflection target plates made of relevant coatings / paints currently available on the market is limited. In particular, diffuse reflection target plates with a reflectivity of less than 2% are difficult to reliably prepare, and require a lot of manpower and materials to ensure that the coating / paint that meets the expected requirements is accurately modulated, which is difficult to meet the test requirements. Therefore, how to design a reliable diffuse reflection target plate with a wide range of reflectivity is a technical problem that needs to be solved in this field.

[0004] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the prior art in the field. Summary of the invention

[0005] In view of one or more problems existing in the prior art, the present invention provides a diffuse reflection target plate, which can achieve reliable reflectivity in a large range and meet testing requirements.

[0006] The diffuse reflection target plate comprises:

[0007] substrate;

[0008] Multiple microstructures;

[0009] Wherein, the plurality of microstructures are distributed on the substrate;

[0010] The substrate has a first reflectivity, and the microstructure has a second reflectivity; the first reflectivity is different from the second reflectivity;

[0011] The target reflectivity of the diffuse reflection target plate is related to the first reflectivity and the second reflectivity.

[0012] According to one aspect of the present invention, the diffuse reflection target plate comprises a plurality of regions, wherein different regions have different target reflectivities.

[0013] According to one aspect of the present invention, the shape of the microstructure includes one or more of a circle, a polygon, and a strip.

[0014] According to one aspect of the present invention, the size and / or spacing of the plurality of microstructures is related to the size of a light spot formed by the light beam incident on the diffuse reflection target plate.

[0015] According to one aspect of the present invention, sizes and / or intervals of the plurality of microstructures are determined according to the first reflectivity, the second reflectivity, and the target reflectivity of the diffuse reflectivity target plate.

[0016] According to one aspect of the present invention, the plurality of microstructures include a plurality of holes disposed on the substrate.

[0017] According to one aspect of the present invention, the plurality of holes include blind holes or through holes, and the shapes of the holes include straight holes or non-straight holes.

[0018] According to one aspect of the present invention, wherein the plurality of holes include through holes, the diffuse reflection target plate further includes a reflective layer located behind the substrate, and the reflective layer is exposed through the through holes.

[0019] According to one aspect of the present invention, the plurality of microstructures include mesh materials or discrete materials covering the substrate.

[0020] The present invention also relates to a test board assembly, comprising:

[0021] A first diffuse reflective target plate as described above; and

[0022] a second diffuse reflective target plate as described above;

[0023] The first diffuse reflection target plate is stacked on the second diffuse reflection target plate.

[0024] According to one aspect of the present invention, the relative positions of the first diffuse reflection target plate and the second diffuse reflection target plate are adjustable to change the target reflectivity of the test plate assembly.

[0025] The present invention also relates to a design method for a diffuse reflection target plate, wherein the diffuse reflection target plate comprises a substrate and a plurality of microstructures distributed thereon, and the design method comprises:

[0026] S11: determining a first reflectivity of the substrate;

[0027] S12: determining a second reflectivity of the microstructure, wherein the second reflectivity is different from the first reflectivity; and

[0028] S13: Determine distribution parameters of the plurality of microstructures on the substrate according to the first reflectivity of the substrate, the second reflectivity of the microstructures and the target reflectivity of the diffuse reflection target plate.

[0029] According to one aspect of the present invention, the distribution parameters include: one or more of the size, spacing, and number of the plurality of microstructures.

[0030] According to one aspect of the present invention, step S13 comprises:

[0031] determining a duty cycle of the plurality of microstructures according to a first reflectivity of the substrate, a second reflectivity of the microstructures, and a target reflectivity of the diffuse reflection target plate; and

[0032] According to the duty cycle, a distribution parameter of the microstructure is determined.

[0033] According to one aspect of the present invention, it also includes: obtaining a spot size of the laser radar on the substrate;

[0034] Wherein the step S13 comprises: determining the distribution parameters of the plurality of microstructures on the substrate according to the first reflectivity of the substrate, the second reflectivity of the microstructure, the target reflectivity of the diffuse reflection target plate and the spot size.

[0035] According to one aspect of the present invention, the microstructure comprises a blind hole or a through hole, wherein the shape of the hole comprises a straight hole or a non-straight hole.

[0036] According to one aspect of the present invention, the plurality of microstructures include mesh materials or discrete materials covering the substrate.

[0037] The present invention also relates to a laser radar testing method, comprising:

[0038] S21: Control the laser radar to emit a detection beam to the diffuse reflection target plate or the test plate assembly as described above, wherein the detection beam is incident on the diffuse reflection target plate or the test plate assembly and is reflected to generate an echo beam;

[0039] S22: receiving the echo light beam through the laser radar and converting it into an electrical signal; and

[0040] S23: Analyze the performance of the laser radar based on the electrical signal.

[0041] In summary, the test board assembly, diffuse reflection target board and its design method and the test method of laser radar of the present invention are introduced in detail. The diffuse reflection target board of the present invention can adjust the duty cycle of the substrate by changing the specifications and / or distribution mode of the microstructure, and then adjust the target reflectivity of the diffuse reflection target board, covering the reflectivity range from 0-100%, which is flexible and reliable. In addition, multiple diffuse reflection target boards can be used in combination to form a test board assembly. By adjusting the relative positions of multiple diffuse reflection target boards, the target reflectivity of the test board assembly can be changed, and the target reflectivity of the test board assembly can also reliably cover the reflectivity range of 0-100%. The design method of the diffuse reflection target board has also been broken through. In addition to adopting the existing method of applying or spraying paint / coating on the substrate, it can be realized by punching holes on the substrate or covering a mesh or discrete material. The design method is more flexible, the preparation process is simple, and it is easy to achieve high-precision design. The diffuse reflection target board / test board assembly of the present invention provides convenient conditions for testing the performance of laser radar point clouds and meets the test requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0043] Figure 1 A schematic diagram of a diffuse reflection target plate according to an embodiment of the present invention is shown;

[0044] Figure 2 A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0045] Figure 3 A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0046] Figure 4 A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0047] Figure 5 A schematic diagram showing the arrangement principle of a microstructure according to an embodiment of the present invention is shown;

[0048] Figure 6a and Figure 6b A schematic diagram showing a microstructure as a blind hole according to an embodiment of the present invention is shown;

[0049] Figure 7a and Figure 7b A schematic diagram showing a microstructure as a through hole according to another embodiment of the present invention is shown;

[0050] Figure 8A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0051] Fig. 9 A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0052] Fig.10 A schematic diagram of a diffuse reflection target plate according to another embodiment of the present invention is shown;

[0053] Fig.11a A schematic diagram of a test board assembly according to an embodiment of the present invention is shown;

[0054] Fig.11b A partial schematic diagram of a test board assembly according to an embodiment of the present invention is shown;

[0055] Fig.12 A flow chart showing a method for designing a diffuse reflection target plate according to an embodiment of the present invention is shown;

[0056] Fig.13a A schematic diagram showing a method for testing a laser radar according to an embodiment of the present invention; and

[0057] Fig.13b A flow chart of a laser radar testing method according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0058] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0062] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0063] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0064] The present invention provides a diffuse reflection target plate, which includes a substrate and a plurality of microstructures, wherein the plurality of microstructures are distributed on the substrate; the substrate has a first reflectivity, and the microstructures have a second reflectivity; the first reflectivity is different from the second reflectivity, and the target reflectivity of the diffuse reflection target plate is related to the first reflectivity and the second reflectivity. The diffuse reflection target plate of the present invention can achieve a reliable large-range reflectivity and meet the test requirements. The following is a detailed introduction.

[0065] Figure 1 A schematic diagram of a diffuse reflection target plate 100 according to an embodiment of the present invention is shown. In this embodiment, the diffuse reflection target plate 100 includes a substrate 101 and a plurality of microstructures 102 distributed on the substrate 101. The shape of the microstructures 102 may be circular. Figure 2 A schematic diagram of a diffuse reflection target plate 200 according to another embodiment of the present invention is shown. In this embodiment, the diffuse reflection target plate 200 includes a substrate 201 and a plurality of microstructures 202 distributed on the substrate 201. The shape of the microstructures 202 may be a quadrilateral. Figure 3 A schematic diagram of a diffuse reflection target plate 300 according to another embodiment of the present invention is shown. In this embodiment, the diffuse reflection target plate 300 includes a substrate 301 and a plurality of microstructures 302 distributed on the substrate 301. The shape of the microstructure 302 can be a strip. According to different embodiments of the present invention, the microstructure can have different shapes. Figure 1-Figure 3 In addition to the circles, quadrilaterals, and strips shown in the figure, the microstructures can also be other regular or irregular shapes, such as polygons (such as triangles, pentagons, hexagons, octagons, etc.), ellipses, semicircles, sawtooth strips, etc. In practical applications, the shape of the microstructure can be flexibly set according to actual needs. It should be understood that the processing difficulty of the microstructure of a regular shape is relatively low and it is easier to implement.

[0066] In some embodiments of the present invention, a plurality of microstructures may be evenly distributed on the substrate to form a uniform microstructure array. Figure 1-Figure 3 , multiple microstructures can be aligned; although not shown in the figure, alternatively, multiple microstructures can also be staggered, for example Figure 1 and Figure 2 In an embodiment, the microstructures of each row (or each column) are staggered relative to the microstructures of adjacent rows (or adjacent columns). Figure 1 The embodiment of the present invention describes how to determine the target reflectivity of the diffuse reflection target plate 100 according to the reflectivity of the substrate 101 and the reflectivity of the microstructure 102.

[0067] Reference Figure 1 , wherein the substrate 101 has a first reflectivity R1 and an area S1, and the microstructure 102 has a second reflectivity R2 and a total area S2. It should be noted that in the present invention, the substrate area refers to the area of ​​the substrate surface, including the area of ​​the microstructure projected onto the plane where the substrate surface is located and the area excluding the microstructure, refer to Figure 1 As shown, the substrate area is the sum of the light-colored part and the shaded part. In addition, in the present invention, the total area of ​​the microstructure refers to the area of ​​the microstructure projected onto the plane where the substrate surface is located (the area of ​​one microstructure is referred to as Figure 6a-7b The range is defined by the dashed line in the figure).

[0068] The target reflectivity R0 of the diffuse reflection target plate 100 is related to the first reflectivity R1 of the substrate 101 and the second reflectivity R2 of the microstructure 102. The target reflectivity R0 can be calculated, for example, as follows:

[0069] R0=R1*(1-S2 / S1)+R2*(S2 / S1).

[0070] Here, the duty cycle α of the substrate 101 can be defined. The duty cycle refers to the ratio of the area of ​​the substrate surface excluding the microstructure projection area to the substrate area (i.e. Figure 1 The ratio of the area of ​​the light-colored part to the area of ​​the substrate), that is, α=1-S2 / S1. Therefore, the target reflectivity of the diffuse reflection target plate 100 can also be expressed as:

[0071] R0=R1*α+R2*(1-α).

[0072] It can be seen that the target reflectivity R0 of the diffuse reflection target plate 100 is related to the first reflectivity R1 of the substrate 101 and the second reflectivity R2 of the microstructure 102, as well as the duty cycle α of the substrate 101. Therefore, the solution of the present invention can adjust the target reflectivity R0 of the diffuse reflection target plate 100 by adjusting the duty cycle α of the substrate 101, so that the target reflectivity R0 of the diffuse reflection target plate 100 can basically cover the reflectivity range from 0-100%.

[0073] Reference above Figure 1 The embodiment of FIG. 1 describes the calculation method of the target reflectivity R0 of the diffuse reflection target plate 100. Figure 2 and Figure 3 The calculation method of the target reflectivity of the diffuse reflection target plates 200 and 300 in the embodiment is the same as Figure 1 The embodiments are basically the same and will not be described again here.

[0074] exist Figures 1 to 3 In the embodiments, the diffuse reflection target plate 100, 200, 300 includes only one area, and the specifications of the multiple microstructures 102, 202, 302 in the area (such as the shape, material, size, reflectivity, distribution density, etc. of the microstructures) are the same and are evenly distributed (same spacing), so that the diffuse reflection target plate 100, 200, 300 has a uniform target reflectivity.

[0075] In some other embodiments of the present invention, the diffuse reflection target plate may further include multiple regions, wherein different regions have different target reflectivities, which will be described in detail below.

[0076] Figure 4A schematic diagram of a diffuse reflection target plate 400 including multiple regions according to an embodiment of the present invention is shown. In this embodiment, the diffuse reflection target plate 400 includes a substrate 401, and the substrate 401 includes two regions, namely a first region Z1 and a second region Z2, and has different target reflectivities, wherein the first region Z1 has a plurality of first microstructures 402-1, and the second region Z2 has a plurality of second microstructures 402-2, wherein the first microstructures 402-1 and the second microstructures 402-2 have different specifications (for example, at least one parameter of the shape, material, size, reflectivity, distribution density, etc. is different). Figure 4 In the embodiment, the first microstructure 402-1 and the second microstructure 402-2 have the same shape (both are circular) and the same material (same reflectivity), but different sizes, wherein the first microstructure 402-1 is smaller in size, and the second microstructure 402-2 is larger in size, and the plurality of first microstructures 402-1 and the plurality of second microstructures 402-2 are evenly distributed in their respective regions Z1 and Z2, respectively, so that the first region Z1 and the second region Z2 have different target reflectivities. Thus, the diffuse reflection target plate 400 can have two different target reflectivities at the same time, thereby reducing the number of diffuse reflection target plates required in the test application, which is beneficial to saving costs, while improving ease of use and improving test efficiency.

[0077] It should be noted that Figure 4 Although the embodiment of the invention is introduced by taking the diffuse reflection target plate including two areas as an example, the present invention is not limited to this. The diffuse reflection target plate may also include more areas, and the specifications of the microstructures in each area are different (for example, at least one of the parameters such as shape, material, size, reflectivity, distribution density, etc. is different), and are evenly distributed in their respective areas, so that different areas of the diffuse reflection target plate have different target reflectivities, and thus the same diffuse reflection target plate can have more different target reflectivities at the same time, thereby further reducing the number of diffuse reflection target plates required in the test scene, which is conducive to further saving costs and further improving ease of use.

[0078] Figure 4 In the embodiment of the diffuse reflection target plate, the specifications of the microstructures in each area are different, but the distribution method is the same, so that different areas can have different target reflectivities. In other embodiments of the present invention, the specifications of the microstructures in each area of ​​the diffuse reflection target plate can be the same (for example, the shape, material, size, reflectivity, distribution density and other parameters are the same), but the distribution method is different (non-uniform distribution, different spacing between microstructures), and different areas can also have different target reflectivities. These are all within the scope of protection of the present invention and can be flexibly set as needed in practical applications.

[0079] The following describes how to determine the target reflectivity of each area of ​​the diffuse reflection target plate by taking a diffuse reflection target plate including two areas as an example. Those skilled in the art should understand that for a diffuse reflection target plate including more areas, the calculation method of the target reflectivity of each area is similar.

[0080] Reference Figure 4 , the first reflectivity of the substrate 401 is R1, the area of ​​the substrate 401 is S1, and it is assumed that the substrate 401 is equally divided into a first region Z1 and a second region Z2 (assuming that the first region Z1 and the second region Z2 have the same area, both S1 / 2), wherein the reflectivity of the first microstructure 402-1 in the first region Z1 and the second microstructure 402-2 in the second region Z2 are the same, both of which are the second reflectivity R2, and the total area of ​​the first microstructure 402-1 is S 2-1 , the total area of ​​the second microstructure 402-2 is S 2-2 ,

[0081] Reference Figure 4 , the first target reflectivity R of the first area Z1 01 The calculation method is as follows:

[0082] R 01 =R1*(1-2S 2-1 / S1)+R2*(2S 2-1 / S1)

[0083] =R1*α1+R2*(1-α1)

[0084] The duty cycle of the first zone Z1 is α1=1-2S 2-1 / S1.

[0085] Reference Figure 4 , the second target reflectivity R of the second area Z2 02 The calculation method is as follows:

[0086] R 02 =R1*(1-2S 2-2 / S1)+R2*(2S 2-2 / S1)

[0087] =R1*α2+R2*(1-α2)

[0088] The duty cycle of the second zone Z2 is α2=1-2S 2-2 / S1.

[0089] It can be seen that for a diffuse reflection target plate including multiple regions, when the reflectivity of the substrate and the microstructure of each region are the same, the target reflectivity of each region is related to the first reflectivity of the substrate, the second reflectivity of the microstructure, and the duty cycle of the substrate of each region. Therefore, the target reflectivity of each region can be adjusted by adjusting the duty cycle of the substrate of each region of the diffuse reflection target plate, so that different regions of the diffuse reflection target plate have different target reflectivities, which can basically cover the reflectivity range from 0-100%, which is flexible and reliable.

[0090] In the solution of the present invention, the duty cycle of the substrate can be adjusted by adjusting the size and / or spacing of the multiple microstructures. The size and / or spacing of the multiple microstructures can be designed according to the purpose of the diffuse reflection target plate and the target reflectivity to be obtained. The influencing factor is that when used for laser radar testing, the spot size formed by the light beam emitted by the laser of the laser radar incident on the diffuse reflection target plate must be able to cover the multiple microstructures. In other words, the size and / or spacing of the multiple microstructures are related to the spot size formed by the light beam incident on the diffuse reflection target plate.

[0091] Reference Figure 5 , the light beam is emitted from the laser of the laser radar, and its size when it is emitted through the transmitting optical component is h, and the far-field emission angle is θ. Then, at a distance d from the laser radar, the light beam is incident on the diffuse reflection target plate (100 / 200 / 300 / 400) to form a spot size L: L = h + 2*d*tan(θ / 2). Since the light beam has a certain divergence angle and the distance between the diffuse reflection target plate and the laser radar is different, the spot size L formed by the light beam on the diffuse reflection target plate will also be different. Based on this, the size and / or spacing of the microstructure can be set according to the test distance range of the diffuse reflection target plate. Specifically, for example, the minimum value d of the test distance range can be used. min The corresponding spot size L min Determine the size and / or spacing of the microstructures, wherein the size and / or spacing of the microstructures is smaller than the spot size L min Preferably, the size and / or spacing of the microstructures is smaller than the spot size L min One to two orders of magnitude lower, for example, enabling the light spot to cover 10-100 or more microstructures.

[0092] In addition, the size and / or spacing of the multiple microstructures can also be determined based on the first reflectivity R1 of the substrate, the second reflectivity R2 of the microstructures, and the target reflectivity R0 of the diffuse reflection target plate. Specifically, the duty cycle of the substrate can be determined based on the first reflectivity R1 of the substrate, the second reflectivity R2 of the microstructures, and the target reflectivity R0 of the diffuse reflection target plate, and the size and / or spacing of the multiple microstructures on the substrate can be determined based on the duty cycle of the substrate. In other words, the duty cycle of the substrate can be determined based on the calculation formula R0=R1*α+R2*(1-α) of the target reflectivity of the diffuse reflection target plate, thereby determining the size and / or spacing of the multiple microstructures.

[0093] The above-mentioned embodiment introduces the process of determining the size and / or spacing of the microstructures. By adjusting the size and / or spacing of multiple microstructures, the duty cycle of the substrate can be adjusted, and then the target reflectivity of the diffuse reflection target plate can be adjusted, so that the target reflectivity of the diffuse reflection target plate can basically cover the reflectivity range from 0-100%, which is flexible and reliable.

[0094] Reference below Figure 6a-Figure 7b ,by Figure 1 The diffuse reflection target plate 100 shown is taken as an example to introduce the specific implementation of the microstructure 102 .

[0095] According to some preferred embodiments of the present invention, the microstructure 102 includes a plurality of holes disposed on the substrate 101. That is, the plurality of microstructures 102 can be realized by drilling holes on the substrate 101. The plurality of holes include blind holes or through holes, and the shape of the holes includes straight holes or non-straight holes. Figure 6a and Figure 6b A schematic diagram showing a blind hole is shown, wherein Figure 6a The blind hole in is a straight hole. Figure 6b The blind holes shown are non-straight holes. Figure 7a and Figure 7b A schematic diagram showing that the hole is a through hole, wherein Figure 7a The through holes shown are straight holes. Figure 7b The holes shown are non-straight holes. It should be noted that the straight holes refer to holes whose side walls are perpendicular to the substrate surface, and the non-straight holes refer to holes whose side walls are not perpendicular to the substrate surface, and the non-straight holes may be trapezoidal holes, for example.

[0096] Reference Figure 6a and Figure 6b , when the microstructure 102 is a blind hole (i.e., a half hole), the substrate 101 has a first reflectivity R1, the total area of ​​the substrate 101 is S1, and the microstructure 102 has a second reflectivity R2 in the area of ​​the projection of the plane where the substrate surface is located, and the total area is S2. It should be noted that Figure 6bIn the embodiment of the present invention, the sidewall and the bottom of the hole may have a uniform second reflectivity R2. The total area S2 of the microstructure refers to the area of ​​the hole shown in the figure projected onto the plane where the substrate surface is located (refer to the range framed by the dotted line in the figure). Figure 6a ,For the case where the microstructure is a straight hole, the total area of ​​the microstructure is the sum of the bottom projection area of ​​the hole (i.e., the bottom area); refer to Figure 6b , when the microstructure is a non-straight hole, the total area of ​​the microstructure is the sum of the bottom projection area and the side wall projection area of ​​the hole. The target reflectivity R0 of the diffuse reflection target plate 100 is calculated as follows:

[0097] R0=R1*(1-S2 / S1)+R2*(S2 / S1)

[0098] =R1*α+R2*(1-α)

[0099] Reference Figure 7a and Figure 7b For the case where the microstructure 102 is a through hole, the target reflectivity R0 will be different depending on the usage scenario of the diffuse reflection target plate 100. If there is no other object behind the diffuse reflection target plate 100 in an open scene, after the light beam passes through the microstructure 102, it cannot be incident on other objects for reflection. In this case, the second reflectivity R2 of the microstructure 102 can be considered to be 0, that is, R2 = 0. If there is other objects behind the diffuse reflection target plate 100 in a non-empty scene, after the light beam passes through the microstructure 102, it is incident on other objects for reflection. In this case, the second reflectivity R2 of the microstructure 102 is not equal to zero, that is, R2 ≠ 0. It can be seen that the second reflectivity R2 of the microstructure 102 is related to whether there are other objects behind it and the reflectivity of the other objects.

[0100] Figure 8 FIG. 5 is a schematic diagram showing a diffuse reflection target plate 500 according to another embodiment of the present invention. Figure 8 , the substrate 501 includes a plurality of microstructures 502, the microstructures 502 are formed by through holes, and the diffuse reflection target plate 500 further includes a reflection layer F located behind the substrate 501, and the reflection layer F is exposed through the through holes. In this embodiment, the reflectivity of the substrate 501 is R1, the reflectivity of the reflection layer F behind the substrate 501 is R2, the total area of ​​the substrate 501 is S1, and the reflection layer F is exposed through the through holes, which can be straight holes or non-straight holes.

[0101] When the microstructure 502 is a through hole and a straight hole, the area of ​​the reflective layer F exposed through the through hole can be regarded as the total area S2 of the microstructure 502, and the target reflectivity R0 of the diffuse reflection target plate 500 is calculated as follows:

[0102] R0=R1*(1-S2 / S1)+R2*(S2 / S1)

[0103] =R1*α+R2*(1-α)

[0104] When the microstructure 502 is a through hole and a non-straight hole, it is necessary to further consider the sidewall of the through hole (refer to Figure 7b ) reflectivity.

[0105] If the reflectivity of the through hole sidewall is the same as the reflectivity of the substrate 501, which is R1, the area of ​​the reflective layer F exposed through the through hole can still be regarded as the total area S2 of the microstructure 502. In this case, the target reflectivity of the diffuse reflection target plate can still be calculated by the above formula.

[0106] On the contrary, if the reflectivity of the through hole sidewall is the same as the reflectivity of the reflective layer F, both being R2, then the area of ​​the reflective layer F exposed through the through hole cannot be simply regarded as the total area S2 of the microstructure 502, but the area S2 of the reflective layer F exposed through the through hole should be regarded as F The projected area S of the through hole side wall w The sum of the total area S2 of the microstructure 502 is regarded as the total area S2 of the microstructure 502. In this case, the target reflectivity R0 of the diffuse reflection target plate is calculated as follows:

[0107] R0=R1*(1-S F / S1-S W / S1)+R2*(S F / S1)+R2*(S W / S1)

[0108] =R1*(1-S F / S1-S W / S1)+R2*(S F +S W ) / S1

[0109] In addition, if the reflectivity of the through hole sidewall is different from the reflectivity of the substrate 501 and the reflective layer F, for example, the reflectivity of the through hole sidewall is R3, the total projected area of ​​the through hole sidewall is S W , then the target reflectivity R0 of the diffuse reflection target plate 500 is calculated as follows:

[0110] R0=R1*(1-S F / S1-S W / S1)+R2*(S F / S1)+R3*(S W / S1)

[0111] Therefore, when the microstructure 502 is a through hole, a reflective layer F with different reflectivity can be set behind the substrate 501 as needed. Through different combinations of the substrate 501 and the rear reflective layer F, the target reflectivity R0 of the diffuse reflection target plate 500 can be flexibly changed, and the change of the target reflectivity R0 caused by different usage scenarios can be avoided or reduced, which is conducive to the stability and reliability of the target reflectivity R0. Further, when the microstructure is a through hole and a non-straight hole, the target reflectivity of the diffuse reflection target plate can be flexibly adjusted by setting the reflectivity of the side wall of the through hole. It should be noted that the present invention does not limit the specific material of the reflective layer F, and the reflective layer F includes but is not limited to a coating plate, a reflective fabric, a reflective ribbon, a reflective silk, a reflective cloth, a reflective leather, a reflective lattice belt, a diamond reflective film, etc. In some embodiments of the present invention, the reflective layer F can be realized by coating. In some embodiments of the present invention, the reflective layer F can also be realized by a target plate made by conventional spraying, which are all within the protection scope of the present invention.

[0112] In Figures 6 to Figure 8 In the embodiment of the present invention, the microstructure is realized by drilling holes in the structure of the substrate itself, and in other embodiments of the present invention, the microstructure can also be realized by covering the surface of the substrate with a material with a special structure. The following is a detailed description.

[0113] Reference Fig. 9 The diffuse reflection target plate 600 includes a substrate 601 and a microstructure 602, wherein the microstructure 602 includes a mesh material covered on the substrate 601. In a specific implementation, the mesh material can be covered on the substrate 601, wherein the reflectivity of the substrate 601 is R1, and the reflectivity of the mesh material itself is R2, together forming the diffuse reflection target plate 600.

[0114] Reference Fig.10 , the diffuse reflection target plate 700 includes a substrate 701 and a plurality of microstructures 702, wherein the plurality of microstructures 702 include discrete materials covered on the substrate 701. In a specific implementation, a sheet of discrete materials can be covered on the substrate 701, wherein the reflectivity of the substrate 701 is R1, and the reflectivity of the surface of the discrete materials is R2, to form the diffuse reflection target plate 700. It should be noted that the specifications (such as material, shape, size, reflectivity, distribution density, etc.) and distribution mode of the mesh material and the discrete materials are not limited by the present invention.

[0115] Reference Fig. 9 and Fig.10, the substrate 601 / 701 has a first reflectivity R1, the mesh material or the discrete material has a second reflectivity R2, the total area of ​​the substrate 601 / 701 is S1, the total area of ​​the mesh material or the discrete material is S2, and the target reflectivity R0 of the diffuse reflection target plate 600 / 700 is calculated as follows:

[0116] R0=R1*(1-S2 / S1)+R2*(S2 / S1)

[0117] =R1*α+R2*(1-α)

[0118] The above embodiments introduce some implementation methods of the microstructure. In addition, the microstructure of the present invention can also be implemented in other ways, that is, spraying a coating / paint with a reflectivity of R2 at a specific position of the substrate, thereby realizing the preparation of the microstructure. Figure 1-Figure 3 In the embodiment of the present invention, coatings are sprayed on the substrate at positions of circular, quadrilateral and strip microstructures, respectively, so as to obtain Figure 1-3 Microstructure 102 / 202 / 302 is shown.

[0119] The diffuse reflection target plate of the present invention is introduced in detail above. The diffuse reflection target plate of the present invention can adjust the target reflectivity of the diffuse reflection target plate by changing the specifications and / or distribution of the microstructure, covering a large reflectivity range, being flexible and reliable, without the need to specially prepare coatings / paints with specific reflectivity.

[0120] The present invention also provides a test board assembly 800, referring to Fig.11a The test board assembly 800 includes a first diffuse reflection target board 801 and a second diffuse reflection target board 802, wherein the first diffuse reflection target board 801 and the second diffuse reflection target board 802 can be respectively Figure 1-Figure 10 The diffuse reflection target plate described in the embodiment of the present invention comprises a first diffuse reflection target plate 801 including a first substrate 801-1 and a first microstructure 801-2, wherein the first microstructure 801-2 is a through hole, and a second diffuse reflection target plate 802 including a second substrate 802-1 and a second microstructure 802-2, wherein the first diffuse reflection target plate 801 is stacked on the second diffuse reflection target plate 802.

[0121] The following takes the case where the microstructures on the first diffuse reflection target plate 801 and the second diffuse reflection target plate 802 are both through holes as an example to introduce the calculation method of the target reflectivity R_eff of the test plate assembly 800.

[0122] Reference Fig.11a and Fig.11b, the reflectivity of the first substrate 801-1 is R1 (i.e., the reflectivity of the light-colored part in the first substrate 801-1), the area of ​​the first substrate 801-1 (including the hole part and the non-hole part) is S11, wherein the area of ​​the hole part is S12, the reflectivity of the second substrate 802-1 is R2 (i.e., the reflectivity of the light-colored part in the second substrate 802-1), the area of ​​the second substrate 802-1 (including the hole part and the non-hole part) is S21, the area of ​​the hole part is S22, and the overlapping area of ​​the first microstructure 801-2 of the first diffuse reflection target plate 801 and the second microstructure 802-2 of the second diffuse reflection target plate 802 (refer to Fig.11b The darkest shaded area in the image is S3. Assuming that there is an open space behind the test board assembly 800, the incident light beam will not be reflected after passing through the overlapping area of ​​the first microstructure 801-1 and the second microstructure 801-2. It can be equivalent to being incident on a place with a reflectivity of 0, that is, assuming that the reflectivity R3 of the overlapping area of ​​the first microstructure 801-1 and the second microstructure 801-2 is zero, that is, R3 = 0. In addition, assuming that the first substrate 801-1 and the second substrate 801-2 have the same size, S11 = S12, and the two are placed overlapping. Observed from the normal incidence angle, the total area of ​​the test board assembly 800 is S, S = S11 = S12, then the target reflectivity R_eff of the test board assembly 800 is calculated as follows:

[0123] R_eff=R1*(1-S12 / S)+R2*(S12-S3) / S+R3*S3 / S

[0124] Preferably, the relative positions of the first diffuse reflection target plate 801 and the second diffuse reflection target plate 802 are adjustable to change the target reflectivity R_eff of the test plate assembly 800, thereby achieving flexible adjustment of the target reflectivity R_eff. The above embodiment is described in detail using the test plate assembly including two diffuse reflection target plates as an example. It should be noted that the number of diffuse reflection target plates included in the test plate assembly, the specifications, quantity, and distribution of the microstructures are not limited by the present invention, and in actual use, they can be flexibly set as needed. In the test plate assembly, a plurality of diffuse reflection target plates are used in combination, so that the substrate duty cycle can be adjusted more flexibly, thereby achieving flexible adjustment of the target reflectivity.

[0125] The present invention also provides a design method 10 for a diffuse reflection target plate as described above, wherein the diffuse reflection target plate comprises a substrate and a plurality of microstructures distributed thereon, Fig.12 , the design method 10 comprises steps S11 to S13:

[0126] In step S11, a first reflectivity R1 of the substrate (101, 201, 301, 401, 501, 601, 701) is determined.

[0127] In step S12, a second reflectivity R2 of the microstructure (102, 202, 302, 402, 502, 602, 702) is determined, wherein the second reflectivity is different from the first reflectivity.

[0128] In step S13, distribution parameters of the plurality of microstructures on the substrate are determined based on a first reflectivity R1 of the substrate (101, 201, 301, 401, 501, 601, 701), a second reflectivity R2 of the microstructure (102, 202, 302, 402, 502, 602, 702) and a target reflectivity R0 of the diffuse reflection target plate.

[0129] According to a preferred embodiment of the present invention, the distribution parameters include: one or more of the size, spacing, and number of the plurality of microstructures.

[0130] According to a preferred embodiment of the present invention, step S13 comprises:

[0131] Determining the duty cycle of the plurality of microstructures according to the first reflectivity R1 of the substrate, the second reflectivity R2 of the microstructures, and the target reflectivity R0 of the diffuse reflection target plate; and

[0132] According to the duty cycle, a distribution parameter of the microstructure is determined.

[0133] According to a preferred embodiment of the present invention, the method further includes: obtaining a spot size of the laser radar on the substrate;

[0134] According to a preferred embodiment of the present invention, step S13 comprises: determining distribution parameters of the plurality of microstructures on the substrate according to a first reflectivity R1 of the substrate, a second reflectivity R2 of the microstructure, a target reflectivity R0 of the diffuse reflection target plate and the spot size.

[0135] According to a preferred embodiment of the present invention, the microstructure comprises a blind hole or a through hole, wherein the shape of the hole comprises a straight hole or a non-straight hole.

[0136] According to a preferred embodiment of the present invention, the plurality of microstructures include mesh materials or discrete materials covering the substrate.

[0137] The present invention also relates to a testing method 20 of a laser radar 1000, referring to Fig.13a and Fig.13bThe laser radar 1000 includes a transmitting device TX, a detecting device RX and a processing device (not shown in the figure), wherein the processing device is coupled with the transmitting device TX and the detecting device RX respectively, wherein the transmitting device TX includes one or more light-emitting units 11, and the detecting device RX includes one or more detection units 12, and the light-emitting units 11 can be paired with the detection units 12 one by one, that is, the number of light-emitting units 11 can be equal to the number of detection units 12, and the echo Light' generated by the reflection of the detection light beam Light emitted by each light-emitting unit 11 will be received and converted by the detection unit 12 paired with it; on the other hand, the echo Light' generated by the reflection of the detection light beams Light emitted by multiple light-emitting units 11 can also be received and converted by one detection unit 12; in addition, the detection light beam Light emitted by one light-emitting unit 11 can also be subdivided into multiple light beams, or gathered to multiple detection units 12 by means of uniform light. Preferably, the light emitting unit 11 may adopt a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser (EEL), and the detection unit 12 may adopt a single photon avalanche diode (SPAD), and each detection unit 12 may include one or more SPADs. Preferably, the multiple transmitting units 11 in the transmitting device TX and the multiple detection units 12 in the detection device RX may be arranged as a one-dimensional linear array or a two-dimensional planar array.

[0138] The test method 20 includes steps S21-S23. In step S21, the laser radar 1000 is controlled to emit a detection beam Light to the diffuse reflection target plate (100 / 200 / 300 / 400 / 500 / 600 / 700) or the test plate assembly 800. The detection beam Light is incident on the diffuse reflection target plate (100 / 200 / 300 / 400 / 500 / 600 / 700) or the test plate assembly 800 and is reflected to generate an echo beam Light'.

[0139] In step S22, the echo light beam Light' is received by the laser radar 1000 and converted into an electrical signal.

[0140] In step S23, the performance of the laser radar 1000 is analyzed based on the electrical signal.

[0141] The diffuse reflection target plate includes the diffuse reflection target plate (100 / 200 / 300 / 400 / 500 / 600 / 700) described above; and the test plate assembly includes the test plate assembly 800 described above.

[0142] In summary, the test board assembly, diffuse reflection target board and its design method and the test method of laser radar of the present invention are introduced in detail. The diffuse reflection target board of the present invention can adjust the duty cycle of the substrate by changing the specifications and / or distribution mode of the microstructure, and then adjust the target reflectivity of the diffuse reflection target board, which basically covers the reflectivity range from 0-100%, which is flexible and reliable. In addition, multiple diffuse reflection target boards can be used in combination to form a test board assembly. By adjusting the relative positions of multiple diffuse reflection target boards, the target reflectivity of the test board assembly can be changed, and the target reflectivity of the test board assembly can also reliably cover the reflectivity range of 0-100%. The design method of the diffuse reflection target board has also been broken through. In addition to adopting the existing method of applying or spraying paint / coating on the substrate, it can be realized by punching holes on the substrate or covering a mesh or discrete material. The design method is more flexible, the preparation process is simple, and it is easy to achieve high-precision design. The diffuse reflection target board / test board assembly of the present invention provides convenient conditions for testing the performance of laser radar point clouds and meets the test requirements.

[0143] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A diffuse reflection target plate, comprising: substrate; Multiple microstructures; Wherein, the plurality of microstructures are distributed on the substrate; The substrate has a first reflectivity, and the microstructure has a second reflectivity; the first reflectivity is different from the second reflectivity; The target reflectivity of the diffuse reflection target plate is related to the first reflectivity and the second reflectivity. 2 . The diffuse reflection target plate according to claim 1 , wherein the diffuse reflection target plate comprises a plurality of regions, wherein different regions have different target reflectivities. 3 . The diffuse reflection target plate according to claim 1 , wherein the shape of the microstructure comprises one or more of a circle, a polygon, and a strip. 4 . The diffuse reflective target plate according to claim 1 , wherein the size and / or spacing of the plurality of microstructures are related to a spot size formed when the light beam is incident on the diffuse reflective target plate.

5. The diffuse reflection target plate according to any one of claims 1 to 4, wherein sizes and / or intervals of the plurality of microstructures are determined according to the first reflectivity, the second reflectivity, and a target reflectivity of the diffuse reflection target plate.

6. The diffuse reflection target plate according to any one of claims 1 to 4, wherein the plurality of microstructures comprises a plurality of holes disposed on the substrate. 7 . The diffuse reflective target plate of claim 6 , wherein the plurality of holes comprise blind holes or through holes, wherein the shapes of the holes comprise straight holes or non-straight holes. 8 . The diffuse reflection target plate of claim 7 , wherein the plurality of holes include through holes, the diffuse reflection target plate further comprising a reflective layer located behind the substrate, the reflective layer being exposed through the through holes.

9. The diffuse reflection target plate according to any one of claims 1 to 4, wherein the plurality of microstructures comprises a mesh material or a discrete material covered on the substrate.

10. A test board assembly comprising: A first diffuse reflection target plate as claimed in any one of claims 1 to 9; and A second diffuse reflection target plate as claimed in any one of claims 1 to 9; The first diffuse reflection target plate is stacked on the second diffuse reflection target plate.

11. The test board assembly of claim 10, wherein the relative positions of the first diffuse reflection target plate and the second diffuse reflection target plate are adjustable to change the target reflectivity of the test board assembly.

12. A method for designing a diffuse reflection target plate, wherein the diffuse reflection target plate comprises a substrate and a plurality of microstructures distributed thereon, the method comprising: S11: determining a first reflectivity of the substrate; S12: determining a second reflectivity of the microstructure, wherein the second reflectivity is different from the first reflectivity; and S13: Determine distribution parameters of the plurality of microstructures on the substrate according to the first reflectivity of the substrate, the second reflectivity of the microstructures and the target reflectivity of the diffuse reflection target plate.

13. The design method according to claim 12, wherein the distribution parameters include: One or more of the size, spacing, and number of the multiple microstructures.

14. The design method according to claim 12, wherein the step S13 comprises: determining a duty cycle of the plurality of microstructures according to a first reflectivity of the substrate, a second reflectivity of the microstructures, and a target reflectivity of the diffuse reflection target plate; and According to the duty cycle, a distribution parameter of the microstructure is determined.

15. The design method according to any one of claims 12 to 14, further comprising: Obtaining a spot size of the laser radar on the substrate; Wherein the step S13 comprises: determining the distribution parameters of the plurality of microstructures on the substrate according to the first reflectivity of the substrate, the second reflectivity of the microstructure, the target reflectivity of the diffuse reflection target plate and the spot size.

16. The design method according to any one of claims 12 to 14, wherein the microstructure comprises a blind hole or a through hole, wherein the shape of the hole comprises a straight hole or a non-straight hole.

17. The design method according to any one of claims 12 to 14, wherein the plurality of microstructures comprise a mesh material or a discrete material covering the substrate.

18. A laser radar testing method, comprising: S21: Control the laser radar to emit a detection beam to the diffuse reflection target plate according to any one of claims 1 to 9 or the test plate assembly according to claim 10 or 11, wherein the detection beam is incident on the diffuse reflection target plate or the test plate assembly and is reflected to generate an echo beam; S22: receiving the echo light beam through the laser radar and converting it into an electrical signal; and S23: Analyze the performance of the laser radar based on the electrical signal.

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