CN218298674U - Homogenization module and point cloud emission system - Google Patents

Abstract

The application discloses a homogenization module and a point cloud emission system. The homogenization module of the present application includes a collimating lens array, an optical sub-divider, and an optical integrator, and the point cloud emission system of the present application includes the homogenization module. From this, can carry out good homogenization to the light of light source outgoing through this homogenization module to make the point cloud pattern more even, improve the detection result degree of accuracy, in addition, reduce the homogenization and/or the reinforcing that light spot quantity can realize the point cloud in the point cloud unit through the adjustment, thereby make the point cloud emission system of this application can use on farther detection distance.

Description

Homogenization module and point cloud emission system

Technical Field

The application relates to the technical field of laser application, in particular to a homogenizing module and a point cloud emission system.

Background

The point cloud emission system is widely applied to ToF (Time of Flight) devices, laser radars and other equipment, and has wide development prospect and market space. Due to the high cost of high power lasers, in order to reduce the cost, a plurality of different laser light sources with lower power are generally used in the spot cloud emission system, however, there is a problem that the characteristic difference between the individual light sources is large, for example, the intensity, beam divergence, angular irradiance, wavelength, pulse shape or thermal distribution difference is large, which affects the spot cloud emission system, so that an uneven spot pattern projection is finally formed.

SUMMERY OF THE UTILITY MODEL

In order to solve the above-mentioned problems in the prior art, in a first aspect of the present application, an embodiment of the present application provides a homogenizing module for homogenizing light emitted from a light source array, the homogenizing module sequentially including, in an emission direction of the light source array:

the central axis of each collimating lens unit of the collimating lens array is coaxially arranged with the center of each light source of the light source array, and the collimating lens array is configured to collimate and emit light emitted from the light source array;

an optical sub-divider configured to sub-divide collimated incident light into a plurality of sub-beams and focus the sub-beams to form secondary light sources, respectively;

and an optical integrator configured to collimate the plurality of sub-beams emitted from the optical sub-splitter on an incident side and to condense and emit light on an exit side.

In one embodiment of the homogenization module of the present application, the optical integrator comprises: the integrator collimation super lens comprises a plurality of sub-regions, the sub-regions are arranged corresponding to the positions and the number of the secondary light sources, and light entering the sub-regions is collimated and emitted out respectively; and an integrator-condensing superlens configured to condense and emit the collimated light beam emitted from the integrator-collimating superlens.

In one embodiment of the homogenization module of the present application, the integrator collimating metalens and the integrator converging metalens are integrally formed.

In one embodiment of the homogenization module of the present application, the collimating lens array comprises or consists of a collimating superlens array.

In one embodiment of the homogenization module of the present application, the aperture k of the collimator lens unit satisfies:

k≥2(d+h)，

where h is the half height of a single light source of the array of light sources and d is the spacing between adjacent light sources.

In one embodiment of the homogenization module of the present application, the spacing d between adjacent light sources satisfies:

d≥2*f*tanθ，

where f is the focal length of a single collimating lens unit and θ is the single light source divergence half-angle.

In one embodiment of the homogenization module of the present application, the spacing d between the optical sub-divider and the optical integrator ₃ Satisfies the following conditions:

d ₃ ＝f ₂ +f ₃ ，

wherein f is ₂ Is the focal length of the optical subdivider, and ₃ the focal length of the light entrance side of the optical sub-divider.

In one embodiment of the homogenization module of the present application, the collimating lens array, optical sub-divider, and optical integrator are combined by a wafer-level package.

In a second aspect of the present application, embodiments of the present application provide a point cloud emission system, comprising:

a light source array comprising m light sources;

the homogenization module is used for homogenizing light emitted from the light source array and converging the light to emit;

a point cloud generating module for generating a point cloud from the light emitted from the homogenizing module, wherein the point cloud comprises a plurality of point cloud units, the number of light spots in each point cloud unit is n,

wherein n is less than or equal to m.

In one embodiment of the point cloud emission system of the present application, the light source array is disposed at an object focus plane of the collimating lens array of the homogenizing module.

In one embodiment of the point cloud emission system of the present application, the point cloud generation module comprises: a converging lens for dividing the light emitted from the homogenizing module into a plurality of sub-beams and converging the light, a point cloud generating lens for modulating the light emitted from the converging lens to generate a point cloud unit; and the point cloud copying lens is used for copying the point cloud unit into a point cloud array.

The technical scheme of this application can realize beneficial effect do:

1. the homogenization module can distribute more uniform energy to the light emitted by the light source array, so that excellent homogenization treatment is realized;

2. compared with the use of a single high-power laser, the homogenization module can remarkably reduce the cost of the whole system;

3. because especially uniform light can be obtained by means of the homogenization module, the point cloud patterns in the point cloud emission system are more uniform, and the detection precision is obviously improved;

4. the number of light spots in the point cloud unit is set in a targeted manner, so that homogenization or enhancement processing can be flexibly performed on the point cloud, and the point cloud emission system can work over a larger distance under the condition of enhancement processing;

5. due to the use of the super lens, the volume and the weight of the whole system can be remarkably reduced, and wafer-level packaging can be realized between the super lens components, so that the whole system is ensured to have higher alignment precision.

Drawings

The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

Fig. 1 shows a schematic structural diagram of an embodiment of the homogenization module of the present application.

Fig. 2 shows a schematic structural view of another embodiment of the homogenization module of the present application.

Fig. 3 shows a schematic structural diagram of an embodiment of the point cloud emission system of the present application.

Fig. 4 shows a comparison graph of point cloud energy provided by the embodiment of the present application.

FIG. 5 shows a schematic structural diagram of a nanostructure element of a superlens embodied by the present application.

Fig. 6 shows a schematic structural diagram of an arrangement of superstructure units provided by an embodiment of the present application.

The reference numerals in the drawings denote:

1. an array of light sources; 2. a collimating lens array; 3. an optical sub-divider; 4. an optical integrator; 41. an integrator collimating superlens; 42. an integrator converging superlens; 5. a converging lens; 6. a point cloud unit generating a lens; 7. a point cloud unit replicating lens; 8. a homogenization module; 91. a substrate; 92. a nanostructure; 93. and (4) filling materials.

Detailed Description

The present application will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like parts throughout. Also, in the drawings, the thickness, ratio and size of the components are exaggerated for clarity of illustration.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, "a," "an," "the," and "at least one" do not denote a limitation of quantity, but rather are intended to include both the singular and the plural, unless the context clearly dictates otherwise. For example, "a component" means the same as "at least one component" unless the context clearly dictates otherwise. "at least one of" should not be construed as limited to the quantity "one". "or" means "and/or". The term "and/or" includes any and all combinations of one or more of the associated listed items.

Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The meaning of "comprising" or "comprises" indicates a property, a quantity, a step, an operation, a component, a part, or a combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts, or combinations thereof.

Embodiments are described herein with reference to cross-section illustrations that are idealized embodiments. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, regions shown or described as flat may typically have rough and/or nonlinear features. Also, the acute angles shown may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.

Point cloud emission systems exist today that introduce a mixing chamber downstream of the light source, homogenize the light beam of the light source array through the mixing chamber comprising a microlens array, and then generate a dot pattern to project. However, the prior art mixing chamber is generally bulky, and due to the use of microlens arrays, the process is complicated and costly, the alignment difficulty is high, and the system accuracy is susceptible to environmental regulations.

Hereinafter, exemplary embodiments according to the present application will be described with reference to the accompanying drawings.

In view of the above, the present application proposes a homogenization module, in particular a homogenization module 8 for a point cloud emission system, as shown in fig. 1, comprising:

a collimating lens array 2, a central axis of each collimating lens unit of the collimating lens array 2 is coaxially arranged with a center of each light source of the light source array 1, and the collimating lens array 2 is configured to collimate light emitted from the light source array 1;

an optical sub-divider 3, the optical sub-divider 3 being configured to sub-divide the collimated incident light into a plurality of sub-beams and to focus the sub-beams respectively to form secondary light sources,

and an optical integrator 4, wherein the optical integrator 4 is configured to collimate the plurality of sub-beams emitted from the optical sub-splitter 3 on the light entrance side and to condense and emit light on the light exit side.

In operation, a light beam having a certain divergence angle is emitted from the light source array 1, the light emitted from the light source array 1 is modulated into collimated light by the collimator lens array 2, and is incident in parallel into the optical sub-splitter 3, the incident light is split into a plurality of fine sub-beams by the optical sub-splitter 3, and is focused in the respective sub-image planes, thereby forming a plurality of secondary light sources, where all the secondary light sources are located in the same plane parallel to the optical sub-splitter 3 as shown in fig. 1. The sub-beams "emitted" from the secondary light source are then processed by the optical integrator 4, in particular by the optical integrator 4, first being collimated on its incoming light side and the collimated sub-beams being converged out on the outgoing light side of the optical integrator 4, so that the energy distribution of the light source is more uniform.

Therefore, light emitted by the light source array 1 is collimated and then forms a plurality of sub-beams with different intensities by the optical subdivider 3, and the sub-beams are all overlapped by the optical integrator 4, so that the intensity of the emergent light beam of the optical integrator 4 is theoretically the sum of the intensities of the sub-beams, and the energy emitted by the light source is uniformly distributed. By the above processing, even if different light sources are used in the light source array 1, the energy distribution of the emitted light becomes more uniform.

The light emitted by the light source array 1 can be distributed with a more uniform energy by means of the homogenization module 8, so that an excellent homogenization process is achieved. Furthermore, the cost of the overall system can be significantly reduced by the homogenization module 8 of the present application compared to using a single high power laser, and the homogenization module 8 can achieve a better light homogenization function compared to using a plurality of different single laser light sources of lower power.

Here, it should be noted that: a superlens is a sub-wavelength artificial nanostructured film that can modulate the amplitude, phase, and polarization of incident light by the nanostructure elements disposed thereon. It should be noted that the nanostructure 92 can be understood as a sub-wavelength structure containing all dielectric or plasmon and capable of causing phase jump, and the nanostructure unit is a structural unit centered on each nanostructure 92 obtained by dividing the superlens.

In the superlens, the nanostructures 92 are periodically arranged on the substrate 91, wherein the nanostructures 92 in each period constitute one superstructured unit. As shown in fig. 5, the nanostructures 92 and the filling material 93 around the nanostructures form a superstructure unit, wherein the superstructure unit is a close-packed pattern, such as a regular quadrangle, a regular hexagon, and the like, each period includes a group of nanostructures 92, and the vertices and/or the center of the superstructure unit may be provided with the nanostructures 92, for example. In the case where the superstructure unit is a regular hexagon, at least one nanostructure 92 is disposed at each vertex and center position of the regular hexagon. Alternatively, in the case of a square, at least one nanostructure 92 is disposed at each vertex and center position of the square. Ideally, the superstructure unit should be a hexagon vertex and center arranged nanostructure 92, or a square vertex and center arranged nanostructure 92, and it should be understood that the practical product may have the absence of the nanostructure 92 at the edge of the superlens due to the limitation of the superlens shape, so that it does not satisfy the complete hexagon/square. The specific superstructure units are formed by regularly arranging the nanostructures 92, and a plurality of superstructure units are arranged in an array to form a super surface structure.

As shown in the left portion of fig. 6, the superstructure unit includes a central nanostructure 92 and 6 peripheral nanostructures 92 surrounding the central nanostructure at equal distances, and each peripheral nanostructure 92 is uniformly distributed along the periphery to form a regular hexagon, which can also be understood as a combination of regular triangles formed by a plurality of nanostructures 92.

In another embodiment of the superstructure unit, shown in the middle part of fig. 6, the superstructure unit comprises one central nanostructure 92 and 4 surrounding nanostructures 92 at equal distances from it, forming a square.

The superstructure units and their close-packed/array may also be in the form of a circumferentially arranged sector, as shown in the right part of fig. 6, comprising two arcuate sides, or a sector of one arcuate side, as shown in the lower left corner region in the right part of fig. 6, with nanostructures 92 disposed at the intersection of the sides and at the center of the sector.

It should be noted that for simplicity and clarity, only the nanostructures 92 disposed at the centers of the superstructure units are illustrated in the drawings, and it should be understood that the nanostructures 92 may be disposed at the vertices, intersections and/or centers of the hexagons, squares, and sectors of the outlines in the drawings.

In an embodiment of the present application, the collimating lens array 2 is preferably constituted by or comprises a collimating metalens array. Thereby, the volume and weight of the system can be further reduced and the integration of the homogenization module 8 can also be further improved.

In one embodiment of the present application, the optical integrator 4 includes: an integrator collimating metalens 41, the integrator collimating metalens 41 including a plurality of sub-regions, the sub-regions being disposed corresponding to the positions and the numbers of the secondary light sources, and collimating and emitting light incident to the plurality of sub-regions, respectively; and an integrator-condensing superlens 42 configured to condense and emit the collimated light beam emitted from the integrator-collimating superlens 41.

In this case, the integrator collimating metalens 41 and the integrator converging metalens 42 can preferably each be formed by a respective metalens, wherein the metalens are each produced separately from one another by semiconductor processes. The integrator collimating metalens 41 and the integrator converging metalens 42 are arranged at a distance from one another and should not be too large in order to prevent an excessively long light path from influencing the collimating effect and to disadvantageously increase the size of the entire homogenization module 8.

In an embodiment of the present invention, in order to ensure good collimation and homogenization, the aperture of a single collimator lens unit is preferably larger than the height of a single light source. And also preferably, the spacing d between adjacent light sources satisfies:

d≥2*f*tanθ，

where f is the focal length of a single collimator lens unit and θ is the half angle of divergence of a single light source, as shown in fig. 1.

Through the arrangement, on one hand, light beams of different light sources in the light source array 1 can not be superposed, so that the homogenization effect of the optical integrator 4 is better; on the other hand, the problem that the light beams from the plurality of light sources cannot be collimated at the edge of the collimating lens unit can be avoided.

Further preferably, the aperture k of the collimator lens unit in the collimator lens array 2 satisfies:

k≥2(d+h)，

where h is the half height of a single light source of the array of light sources.

Thereby, the aperture D of the entire collimator lens array 2 satisfies:

D＝nk，

wherein n is the number of the light sources in the light source array 1 or the collimating lens units in the collimating lens array 2, and n is more than or equal to 2.

In one embodiment of the present application, the light source array 1 is disposed at the object focal plane where the collimating lens array 2 is disposed, that is, satisfies:

d ₁ ＝f ₁ ，

wherein f is ₁ For collimating each of the lens arrays 2A focal length of the collimator lens unit, and d ₁ Is the spacing between the light source array 1 and the collimating lens array 2. This ensures good collimation of the light from the light source.

In one embodiment of the present application, the spacing d between the optical sub-divider 3 and the optical integrator 4 ₃ Satisfies the following conditions:

d ₃ ＝f ₂ +f ₃ ，

wherein f is ₂ Is the focal length of the optical sub-divider 3, and ₃ is the focal length of the light entrance side of the optical integrator 4. It should be explained here that since the optical subdivider 3 subdivides the collimated incident light into a plurality of sub-beams and focuses them to form the secondary light sources, respectively, this can be understood as the presence of a corresponding sub-superlens unit for each sub-beam generated, and the focal length of the optical subdivider 3 can then be the focal length of this sub-superlens unit. In the same way, the focal length of the light entry side of the optical integrator 4 can be understood as the focal length of the respective sub-collimating metalens, for example of the integrator collimating metalens 41. With this arrangement, a good light energy homogenization distribution can be ensured.

In one embodiment of the present application, the collimating lens array 2, the optical sub-divider 3, and the optical integrator 4 are preferably bonded by a wafer level package, in which case all optical elements are constituted by superlenses. In this way, a high alignment accuracy is ensured at the same time, and the entire homogenization module 8 is more robust, given the small size and light weight of the entire homogenization module 8.

In fig. 2, a second embodiment of a homogenization module 8 according to the application is shown, which differs from the embodiment according to fig. 1 only in that: in the optical integrator 4, the integrator collimating metalens 41 and the integrator converging metalens 42 are integrally configured. Here, the integrator collimating metalens 41 and the integrator converging metalens 42 may also be manufactured separately from each other by semiconductor processes and then closely bonded to each other, for example, by pasting. Preferably, the integrator collimating metalens 41 and the integrator converging metalens 42 may also be co-fabricated on one substrate 91 by semiconductor processes, for example on both sides of the same substrate 91, respectively. By this embodiment, the volume and weight of the entire homogenization module 8 can be further reduced.

In other respects, the homogenization module 8 according to the embodiment of fig. 2 is identical to the homogenization module 8 according to the embodiment of fig. 1.

In a second aspect of the present application, a point cloud emission system is proposed, as shown in fig. 3. The point cloud emission system includes:

a light source array 1, wherein the light source array comprises m light sources;

a homogenizing module 8 according to one of the embodiments of the present application, for homogenizing the light emitted from the light source array 1 and converging the light to emit;

a point cloud generating module for generating a point cloud from the light emitted from the homogenizing module 8, wherein the point cloud comprises a plurality of point cloud units, the number of light spots in each point cloud unit is n,

wherein n ≦ m, preferably n < m.

In operation of the point cloud emission system, the light beams emitted by the light source array 1 are homogenized and uniformly converged by the homogenizing module 8. The converging light beam from the homogenization module 8 is received by a point cloud generation module and a point cloud is generated.

Preferably, the point cloud generating module comprises: a condensing lens 5 for dividing the light emitted from the homogenizing module 8 into a plurality of sub-beams and condensing; a point cloud unit generating lens 6 for generating a point cloud unit from the light emitted from the condenser lens 5; and the point cloud unit copying lens 7 is used for copying the point cloud units into a point cloud unit array of a space, namely generating point clouds.

Here, it is preferable that the condensing lens 5, the point cloud unit generating lens 6, and the point cloud unit duplicating lens 7 are each constituted by a superlens, whereby the weight and volume of the point cloud emission system can be further reduced. Further, the condensing lens 5, the point cloud unit generating lens 6, and the point cloud unit replicating lens 7 may also be preferably bonded together by wafer level packaging, thereby further reducing the volume and ensuring high precision alignment. In a further preferred embodiment of the application, the entire homogenization module 8 and the point cloud generation module are each formed by a correspondingly functional superlens and are combined together with the light source array 1 by wafer-level packaging, whereby a particularly compact point cloud emission system is achieved.

Here, in the case of n = m, that is, in the case that the number of light spots is the same as the number of light sources, the homogenization module 8 according to the present application is adopted, so that the point cloud pattern emitted by the point cloud emission system of the present application is more uniform, and thus the detection accuracy is significantly improved.

Whereas in case n < m, i.e. the number of light spots is smaller than the number of light sources, the energy of the individual point clouds is also enhanced by the homogenization module 8 according to the present application while homogenization takes place, whereby the point cloud emission system can work over larger distances.

The above has been confirmed by the inventors through experiments. Wherein the energy q of a single point cloud unit is characterized by:

wherein E is the energy of a single light source, s is the copy number of the point cloud unit, m is the number of the light sources, and n is the number of the light spots in the point cloud unit.

Fig. 4 is a comparison graph of point cloud energy provided by the embodiment of the present application, where the rightmost bar in fig. 4 is a brightness representation, and the brightness gradually decreases from top to bottom. The number of light sources is 4, the number of light spots of a single point cloud unit is 4 in the scheme of the left figure, and 3 in the scheme of the right figure, the number of replicated patterns is 9, here a 3 x 3 matrix. Here, the energy provided by the 4 light sources is, in turn: 1.3w, 1.2w, 0.9w and 1.0w. As can be seen from fig. 4, by reference to the luminance bars, the light spots are significantly brighter in the right image than in the left image, i.e. the single point energy density of the left image is: 0.61w/mm ² (ii) a And the right graph single point energy density is: 0.82w/mm ² . Therefore, the energy improvement of a single light spot in any point cloud unit provided by the scheme of the right image is large, and the method is suitable for small-angle remote detection.

In one embodiment of the point cloud emitting system of the present application, the point cloud unit replication lens 7 can also employ a Diffractive Optical Element (DOE), which is a common element in the prior art and thus is not described in detail.

Therefore, by means of the point cloud emission system of the embodiment, homogenization or enhancement processing can be flexibly performed on the point cloud by setting the number of the light spots in the point cloud unit in a targeted manner, and under the condition of enhancement processing, the point cloud emission system can work in a longer distance.

The above description is only a specific implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the embodiments disclosed in the present application, and all the changes or substitutions should be covered by the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.

Claims (11)

1. A homogenization module for homogenizing light emerging from a light source array (1), characterized in that it comprises, in succession in the direction of emergence of the light source array (1):

the central axis of each collimating lens unit of the collimating lens array (2) is coaxially arranged with the center of each light source of the light source array (1), and the collimating lens array (2) is configured to collimate and emit light emitted from the light source array (1);

an optical sub-divider (3), the optical sub-divider (3) being configured to sub-divide collimated incident light into a plurality of sub-beams and to focus the sub-beams respectively to form secondary light sources;

and an optical integrator (4), wherein the optical integrator (4) is configured to collimate the plurality of sub-beams emitted from the optical sub-splitter (3) on the light-entering side and to converge and emit light on the light-emitting side.

2. The homogenization module of claim 1, wherein the optical integrator (4) comprises:

an integrator collimation superlens (41), wherein the integrator collimation superlens (41) comprises a plurality of sub-areas which are arranged corresponding to the positions and the number of the secondary light sources and respectively collimate and emit light incident to the plurality of sub-areas; and

an integrator-condensing superlens (42) configured to condense and emit the collimated light beam emitted from the integrator-collimating superlens (41).

3. The homogenization module of claim 2 wherein the integrator collimating metalens (41) and the integrator converging metalens (42) are integrally formed.

4. The homogenization module according to claim 1, wherein the collimator lens array (2) comprises or consists of a collimator superlens array.

5. The homogenization module of claim 1 wherein the aperture k of the collimating lens unit satisfies:

k≥2(d+h)，

where h is the half height of a single light source of the array (1) of light sources and d is the spacing between adjacent light sources.

6. The homogenization module of claim 1 wherein the spacing d between adjacent light sources satisfies:

d≥2*f*tanθ，

where f is the focal length of a single collimator lens unit and θ is the half angle of divergence of a single light source.

7. Homogenization module according to claim 1, wherein the spacing d between the optical sub-divider (3) and the optical integrator (4) ₃ Satisfies the following conditions:

d ₃ ＝f ₂ +f ₃ ，

wherein f is ₂ Is the focal length of the optical sub-divider (3), and f ₃ Is the focal length of the light inlet side of the optical integrator (4).

8. The homogenization module of any of claims 1 to 7, wherein the collimating lens array (2), the optical sub-divider (3) and the optical integrator (4) are bonded by wafer level packaging.

9. A point cloud emission system, comprising:

a light source array (1), the light source array (1) comprising m light sources;

a homogenization module (8) as claimed in any of claims 1 to 8 for homogenizing and converging light exiting the light source array (1);

a point cloud generation module for generating a point cloud from the exit light of the homogenization module (8), wherein the point cloud comprises a plurality of point cloud units, the number of light spots in each of which is n,

wherein n is less than or equal to m.

10. The point cloud emission system of claim 9, characterized in that the light source array (1) is arranged at an object focus plane of a collimator lens array (2) of the homogenization module (8).

11. The point cloud emission system of claim 10, wherein the point cloud generation module comprises:

a converging lens (5) for dividing the light exiting from the homogenizing module (8) into a plurality of sub-beams and converging the same;

a point cloud generating lens (6) for modulating the light emitted by the converging lens (5) to produce a point cloud unit;

a point cloud duplicating lens (7) for duplicating the point cloud unit into a point cloud array.

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