Beam shaper, LiDAR system and laser beam deformation conversion method

Abstract

The LiDAR system provided by the invention comprises a beam shaper which is used for carrying out deformation conversion on a linear laser beam collimated by a lens. This conversion may minimize divergence of the beam along the scanning axis while enlarging its size in a direction perpendicular to the axis. The deformed beam can be refocused to accommodate the size of a scanning device (e.g., MEMS mirror) while maintaining the angular resolution of the LiDAR system.

Description

Technical Field

[0001] Embodiments of the present invention relate to remote sensing, and more particularly to an apparatus, system, and method for deforming a laser beam to match the size of an optical scanning instrument (e.g., a micro-electromechanical system (MEMS) mirror) used in a light detection and ranging (LiDAR) device. Background Art

[0002] In the field of solid-state LiDAR, which is known for its durability and cost-effectiveness due to the lack of moving parts, precise beam shaping is crucial. There are two main types of solid-state LiDAR: flash LiDAR, which illuminates the entire scene at once but suffers from a low signal-to-noise ratio due to its flood illumination method; and scanning LiDAR, which selectively illuminates parts of the scene.

[0003] Scanning LiDAR, whether using mechanical methods such as MEMS mirrors or non-mechanical technologies such as optical phased arrays or plasma metasurfaces, requires a laser beam with a specific shape and size to be aligned with the scanning instrument (e.g., MEMS mirror). Laser beams emitted by high-power lasers typically have large beam sizes. Focusing these beams directly into a small diameter to match the size of the scanner may result in poor LiDAR angular resolution. Smaller scanners are not only more mechanically robust than larger scanners, but are also easier to manage in terms of temperature control. Summary of the invention

[0004] The present invention describes a system and method for laser beam deformation transformation to adjust the aspect ratio of the laser beam to obtain an optimized beam profile. This adjustment not only improves the efficiency of the LiDAR system, but also ensures a high-quality laser beam. In the present invention, the embodiments of non-isomorphic beam transformation are explained in the context of MEMS mirror-based scanning LiDAR. However, these embodiments are also applicable to other scanning LiDAR systems.

[0005] The LiDAR system may include a beam shaper designed to deform a linear laser beam after being collimated by a lens. The purpose of this improvement is to minimize the divergence of the beam along the scanning axis while enlarging its size perpendicular to the axis. The deformed laser beam can be refocused to correspond to the size of the scanning device (such as a MEMS mirror) while achieving the highest angular resolution of the LiDAR system. This method is more advantageous than directly focusing the laser beam to a smaller diameter to match the scanner, which directly focuses the laser beam to a smaller size, resulting in a high beam divergence angle of the LiDAR system, thereby affecting the angular resolution of the LiDAR system. This beam shaping function can be achieved by using prism array pairs, double-sided transmission diffraction grating elements, plasmonic metasurfaces, or topological optics.

[0006] The beam shaper may include two parts, the first part splits the vertical linear laser beam collimated by the lens into a plurality of beam segments and directs all the beam segments to the second part to form a horizontally aligned linear laser beam, and the second part homogenizes the horizontal linear laser beam to generate an improved laser beam. The improved laser beam may be reshaped to match the size of the scanner of the LiDAR system by changing the curvature on the beam shaper or a separate lens.

[0007] The invention also describes a method for deforming and transforming a laser beam.

[0008] The above invention content does not include an exhaustive list of all embodiments of the present invention. All devices and methods in the present invention can be implemented by all appropriate combinations of the various aspects and embodiments described in the present invention. Instruction Manual

[0009] Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references refer to similar elements.

[0010] Figure 1 Detailed description of the invention The LiDAR system implemented in various embodiments of the present invention.

[0011] Figure 2 FIG. 4 is a schematic diagram of a laser beam deformation conversion system according to an embodiment of the present invention.

[0012] Figure 3 is a schematic diagram of a system according to an embodiment of the present invention.

[0013] Figure 4 FIG. 4 is another schematic diagram of a system according to an embodiment of the present invention.

[0014] Figure 5 FIG. 4 is a schematic diagram of a process of implementing deformation conversion of a laser beam according to an embodiment of the present invention.

[0015] Figure 6 The light intensity distribution of the laser beam before the second prism array according to an embodiment of the present invention is shown.

[0016] Figure 7 An example far-field pattern of a laser beam after passing through a beam shaper according to an embodiment of the present invention is shown.

[0017] Figure 8 The process of performing laser beam deformation conversion in a LiDAR device according to an embodiment of the present invention is demonstrated. DETAILED DESCRIPTION

[0018] Figure 1 To implement various embodiments of the present invention, a LiDAR system 101 is provided.

[0019] The LiDAR system 101 may be a solid-state LiDAR system that can measure the distance to an object by illuminating the object in the environment with laser pulses. The difference in return time and wavelength of the reflected laser pulses can be used to create a point cloud of the environment. The point cloud can provide spatial position and depth information to identify and track objects.

[0020] like Figure 1 As shown, the LiDAR system 101 may include a laser pulse emitting unit 104, a laser pulse scanner 105, a laser pulse receiving unit 109, and a control unit 107. The laser pulse emitting unit 104 may include one or more short-pulse laser emitters that emit laser photons.

[0021] The laser pulse emitting unit 104 is used to emit a pulsed laser beam 113. The pulsed laser beam 113 can be directed or scanned in one or more directions by a laser pulse scanner 105 using a variety of devices, including a MEMS mirror, one or more optical phase arrays (OPA) and a plasma element surface. Each of the one or more directions is referred to as a directional direction or a scanning direction. The laser pulse scanner 105 can direct one or more laser beams in a directional direction. Each laser beam can have a fixed number of pulses.

[0022] The control unit 107 may include control logic implemented in hardware, software, firmware, or a combination thereof. The control logic 107 may drive the other units or subsystems 104, 105, and 109 of the LiDAR system 101 in a coordinated manner, and may execute one or more data processing algorithms to perform one or more operations for signal filtering and object detection. For example, the control unit 107 may synchronize the laser pulse emission unit 104 and the laser pulse scanner 105 so that the laser pulse scanner 105 can scan in multiple horizontal fields of view.

[0023] The laser pulse receiving unit 109 can use one or more imaging lenses (e.g., imaging lens 111) to collect one or more laser pulses (e.g., laser pulse beam 112) reflected from the target object 103, and focus the laser pulse beam to one or more photodetectors (e.g., photodetector 117). Each photodetector can be a high-sensitivity photodiode, such as a linear mode avalanche photodiode (APD) or a single photon avalanche diode (SPAD). The return signal on each photodetector collected from the imaging lens 111 can be sent to the control unit 107 for processing.

[0024] In one embodiment, the laser diode in the laser pulse emission unit 104 can be operated in a pulse mode, with pulses repeating at fixed intervals (e.g., every few microseconds), or can be repeated at non-periodic intervals. The laser diode and laser driving circuit can be selected based on predetermined performance parameters of the LiDAR system 101, for example, the predetermined performance parameters are the required maximum range and resolution of the scanned space.

[0025] In one embodiment, MEMS mirrors as beam scanners in solid-state LiDAR have advantages over other beam scanning methods. One advantage is the smaller size, which allows for a more compact design of the LiDAR system, which is beneficial for some applications with space and weight constraints, such as applications on drones or handheld devices.

[0026] In one-dimensional beam scanning or two-dimensional beam scanning, the horizontal scanning beam from the MEMS mirror is diffused into a vertical laser line by a diffusion lens. The horizontal resolution depends on the measurement sampling rate and the scanning frequency of the MEMS mirror. The photodetector array (parallel to the laser line) is placed behind the imaging lens. The vertical resolution depends on the number of photodetector components. Optionally, the horizontal laser line is scanned vertically to cover the entire field of view. In one embodiment, the LiDAR resolution depends on the divergence angle of the laser beam in the scanning direction.

[0027] Figure 2 FIG. 2 is a schematic diagram of a laser beam deformation conversion system 200 according to an embodiment of the present invention.

[0028] like Figure 2 As shown, the system 200 may include a laser pulse emission unit 104, a lens 203, and a beam shaper 205. The laser pulse emission unit 104 may include an edge emitting laser diode (EELD) array and a vertical cavity surface emitting laser (VCSEL) array. A VCSEL array is a semiconductor laser array in which each laser (or VCSEL) emits photons vertically to the surface of a semiconductor chip. The VCSEL array may include a plurality of VCSELs organized in a grid or linear pattern on a single semiconductor substrate. Each VCSEL in the array can be individually addressed and controlled to achieve complex and high-resolution emission patterns. In one embodiment, the linear laser beam emitted by the laser pulse emission unit 104 extends along the x (vertical) direction, such as the fast axis of the laser pulse emission unit 104.

[0029] In one embodiment, the lens 203 is a composite cylindrical lens, which can project the laser beam emitted by the laser pulse emission unit 104 onto the beam shaper 205 and collimate the laser beam to reduce its divergence and increase its size.

[0030] In one embodiment, the beam shaper 205 may include a beam deflector 207 and a beam homogenizing element 209. The beam deflector 207 and the beam homogenizing element 209 are manufactured as a complementary pair.

[0031] In one embodiment, the beam deflector 207 can divide the linear laser beam from the laser pulse emission unit 204 and elongated in the x-direction into a plurality of beam segments. For example, the beam deflector 207 divides the linear laser beam into odd-numbered segments. In various other embodiments, the number of segments of the linear laser beam can be even or any other number suitable for implementing the techniques described herein. The beam deflector 207 maintains the direction of the central beam segment unchanged and deflects one or more beam segments located above the central segment downward to the right or left of the central beam segment. Similarly, the beam deflector 207 deflects one or more segments located below the central beam segment upward to the left or right of the central beam segment. Therefore, when these beam segments reach the beam homogenizing element 209, all beam segments, including the beam segments above and below the central beam segment, are realigned along the y-direction to form a linear laser beam aligned with the central beam segment.

[0032] In one embodiment, the beam homogenizing element 209 and the beam deflector 207 are manufactured as a complementary pair, so that the beam homogenizing element 209 can increase the size of each beam segment in the y direction and reduce its size in the x direction. In addition, the beam homogenizing element 209 can compensate for the difference in propagation angles of the beam segments. However, in one embodiment, the beam homogenizing element 209 does not change the divergence angle of each beam segment in the linear laser beam in the x direction or the y direction.

[0033] After the above optical operations, the system 200 effectively changes the laser beam from the lens 203 disproportionately in one direction to another direction, thereby achieving an anamorphic transformation of the laser beam. The anamorphic transformation can take different shapes depending on the number of beam segments generated by the beam deflector 207. For example, the beam deflector 207 divides the laser beam emitted from the lens 203 into three beam segments, and the size of the laser beam emitted from the lens 203 in the x direction is one-third of the original size, and the size of the laser beam in the y direction is three times the original size.

[0034] After the anamorphic transformation, the laser beam directly emitted by the laser pulse emission unit 104 has a reduced divergence in the x-direction (e.g., scanning direction) and an increased divergence in the orthogonal direction, although the beam homogenization element 209 does not change the divergence of each beam segment in any direction. This anamorphic transformation maintains the overall (two-dimensional) optical brightness, but can still significantly improve the angular resolution without causing significant light loss.

[0035] Figure 32 is a schematic diagram of a system 200 according to an embodiment of the present invention. In this embodiment, a pair of prism arrays 304 and 308 are used to implement Figure 2 The beam shaper 205 shown in the figure is used, and the laser beam emitted from the laser pulse emission unit 104 is divided into three segments 303, 305 and 307 after passing through the lens 203, and its divergence is reduced and its size is increased in the x direction while the divergence and size in the y direction are kept unchanged, so as to collimate the laser beam. In one embodiment, the lens 203 vertically collimates the laser beam along the y direction.

[0036] In one embodiment, the prism arrays 304 and 308 have the same number of prisms. The prisms of each prism array have the same structure. The deflection angle of the prisms in the first prism array 304 and the spacing between the two prism arrays 304 and 308 are designed to align the three beam segments horizontally (y direction), as shown in the laser beam 306 in the figure, which includes three beam segments 303, 305 and 307, but they do not overlap before reaching the second prism array 308. However, due to the deflection angle on the first prism array 304, the three beam segments 303, 305 and 307 have different propagation angles before reaching the second prism array 308.

[0037] In one embodiment, the second prism array 308 can receive the beam segments 303, 305, and 307 as beam segments 309, 311, and 313, respectively, and homogenize the three beam segments by compensating for the difference in their propagation angles, thereby producing a more uniform output beam 210. The output beam 210 can be reshaped by the curvature or lens on the beam shaper 205 to match the size of the MEMS mirror 211. In one embodiment, the output beam 210 is horizontally widened after passing through the second prism array 308, indicating that the laser beam has diverged in the x-direction. In one embodiment, the second prism array does not change the vertical size of the output beam 210. In one embodiment, the vertical size of the output beam 210 is the same as the vertical size of any of the three beam segments 309, 311, and 313.

[0038] Figure 4Schematic diagram of another embodiment of the system 200 according to an embodiment of the present invention. In this embodiment, a double-sided transmission diffraction grating element 400 is used to implement the beam shaper 205. The transmission grating element 400 may include diffraction gratings 403 and 406 etched on the front side 401 and the back side 404 of the substrate. The diffraction grating 403 on the front side 401 of the substrate divides the incident linear laser beam into three independent beam segments, while the diffraction grating 406 on the back side 404 recombines these beam segments into a single, transformed, uniform output beam. The thickness of the diffraction grating is determined by the deflection angle of the beam and the spot size. The beam shaper manufactured in this way is simpler and more accurate than the prism-type structure.

[0039] In one embodiment, the diffraction gratings 403 and 406 may be designed so that they are aligned in two orthogonal directions (eg, Figure 2 The deformed diffraction grating diffracts light in different ways in the x and y directions (in the grating), thereby deforming the beam profile. For example, a deformed diffraction grating has groove spacing that varies on two main axes (i.e., the fast and slow axes). When light is diffracted from the grating, the diffraction angles on the two axes are different, thereby achieving a deformed conversion. The degree of deformation can be adjusted by changing the groove density or the angle of incidence on the grating.

[0040] Figure 5 2 is a schematic diagram of a process for implementing a deformation transformation of a laser beam according to an embodiment of the present invention. More specifically, the figure is a phase space representation of the deformation transformation of a laser beam as it passes through various optical elements in the system 200, ultimately producing a beam with improved divergence and size suitable for enhanced applications.

[0041] At step 501, the laser emission is characterized by a significant divergence in the fast axis, represented by the longer arrow in the phase space representation. To correct for this divergence, the beam first encounters a composite cylindrical lens system (not shown) for collimating the beam, thereby greatly reducing the divergence along the fast axis while increasing the size of the beam. This collimation step is shown in step 503 of the figure.

[0042] Subsequently, the collimated beam enters the prism array as at step 505, whereupon it is split into three different beam segments 1, 2, and 3. Each beam segment is manipulated differently: as shown in the phase space diagram step 507, the top beam segment of the beam is deflected to the lower left, the bottom beam segment is deflected to the upper right, and the middle beam segment maintains its trajectory. The deflection angles, the precise spacing between the two prism arrays, and other carefully calculated configurations ensure that the three beam segments are re-aligned horizontally. This horizontal alignment is achieved before the beam enters the second prism array. The three beam segments are aligned horizontally, but maintain their respective propagation directions without overlapping, ensuring that each beam segment has a unique contribution to the final beam profile.

[0043] After interacting with the second prism array in step 509, the propagation angle difference is compensated, thereby producing a uniformly transformed output beam. This operation does not change the divergence angle of the original beam segment, but changes the size of the beam in step 503 on the x-axis and y-axis and the divergence angle of the beam in step 503 in the y direction.

[0044] Figure 6 The light intensity distribution of the laser beam 306 before the second prism array 308 according to an embodiment of the present invention is shown. In the figure, the dotted line indicates the position of the second prism array 308. Both the left and right beam segments are truncated to obtain better beam quality, while the optical efficiency is slightly reduced.

[0045] Figure 7 An example far-field pattern of laser beam 210 after passing through beam shaper 205 is shown in accordance with an embodiment of the present invention. Figure 7 The image in is a visualization of the far-field laser intensity distribution, where the three beam segments are intentionally separated for demonstration purposes. The intensity pattern shows horizontal alignment and slight vertical expansion, which is consistent with the described deformation process. The total divergence of the beam is very narrow, for example 0.09 degrees, indicating that the beam is highly collimated.

[0046] The above laser beam can be emitted by a 1×4 905nm laser array with an emission aperture of 10μm×1mm. For this laser beam, the 1 / e2 beam divergence angles of the fast axis and slow axis are 40° and 13° respectively. After passing through the beam shaper, the M of the fast axis is 2 From 36 to 12, while the slow axis M 2 From 880 to 2640. Therefore, in the fast axis, the beam can be focused within 0.1° and 2mm beam diameter. Taking into account the bending of the outer beam segment, the overall beam divergence is 0.09°. With a beam intensity non-uniformity better than 10%, the overall conversion efficiency can reach more than 90%.

[0047] Figure 8 A process 800 for deforming a laser beam in a LiDAR device according to an embodiment of the present invention is shown. The process 800 may be performed by a beam shaper, which may be a pair of prism arrays or a double-sided transmission grating element.

[0048] like Figure 8As shown, in step 801, a first unit of a beam shaper receives a linear laser beam from a lens, wherein the linear laser beam extends along a first direction. In step 803, the first unit of the beam shaper divides the laser beam into a plurality of beam segments. In step 805, the first unit of the beam shaper deflects one or more of the plurality of beam segments to a second unit so that each of the plurality of beam segments is linearly shaped and aligned along a second direction orthogonal to the first direction. In step 807, the beam shaper homogenizes the plurality of beam segments to generate a second laser beam extending along a second direction.

[0049] In particular embodiments, certain features described herein in the context of separate embodiments or embodiments may also be combined and implemented in a single embodiment. Conversely, features described in a single implementation may also be implemented in multiple embodiments or any suitable subcombination. In addition, although the above features may be described as functioning in certain combinations, or even initially claimed in this form, in some cases, one or more features may be eliminated from the claimed combination, and the claimed combination may be a subcombination or a variation of a subcombination.

[0050] Although each operation is described in the accompanying drawings as being carried out in a specific order, this should not be understood as having to perform these operations in the specific order shown or in order, or having to perform all these operations. In addition, the accompanying drawings can be described in the form of a flow chart or sequence diagram to describe one or more example processes or methods in general. However, other operations that are not described may be incorporated into the example processes or methods described in general. For example, one or more additional operations may be performed before, after, simultaneously or therein any described operation. In addition, if applicable, one or more operations described in the figure may be repeated. In addition, the operations described in the figure may be performed in any appropriate order. In addition, although specific components, devices or systems are described herein as performing specific operations, any suitable combination of any suitable components, devices or systems may be used to perform any suitable operation or combination of operations. In some cases, multitasking or parallel processing operations may be performed.

[0051] Various embodiments have been described herein in conjunction with the accompanying drawings. However, it should be understood that these drawings are not necessarily drawn to scale. For example, the distances or angles described in the drawings are exemplary and do not necessarily have an exact relationship to the actual size or layout of the device shown.

[0052] The scope of the present invention includes all changes, substitutions, variations and modifications to the example embodiments described or illustrated herein that are understood by those of ordinary skill in the art. The scope of the present invention is not limited to the example embodiments described or illustrated herein. In addition, although the present invention describes respective embodiments including specific components, elements, functions, operations or steps, any of these embodiments may include any combination or arrangement of the components, elements, functions, operations or steps described herein that will be understood by those of ordinary skill in the art.

[0053] The term "or" as used herein should be interpreted as an inclusive "or", meaning any one or any combination thereof, unless otherwise specifically stated or indicated by the context. Thus, the expression "A or B" herein means "A, B, or both A and B". As another example, "A, B, or C" herein means at least one of the following options: A; B; C; A and B; A and C; B and C; A, B, and C. This definition will be an exception if a combination of components, elements, functions, operations, or steps are inherently mutually exclusive to some extent.

[0054] As used herein, expressions of approximation, such as, but not limited to, the words "approximately", "substantially" or "about" mean that, when modified in this way, it is understood that it is not necessarily absolute or perfect, but will be considered close enough to the ordinary skill in the art to ensure that the specified condition exists. The degree of variation described will depend on how much variation can be established, and the ordinary technicians in the art can still identify the modified features as having the features or capabilities required for the unmodified features. In general, but subject to the previous discussion, the numerical values ​​modified by the approximate words such as "approximately" in this article may differ from the values ​​by ±0.5%, ±1%, ±2%, ±3%, ±4%, ±5%, ±10%, ±12% or ±15%. As used herein, the terms "first", "second", "third", etc. can be used as labels for the nouns in front of them, and these terms do not necessarily mean a specific order (e.g., a specific spatial, temporal or logical order). As an example, the system can be described as determining a "first result" and a "second result", and the terms "first" and "second" do not necessarily mean that the first result has been determined before the second result.

[0055] In the foregoing specification, embodiments of the present invention have been described with reference to specific exemplary embodiments thereof. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are therefore to be considered in an illustrative rather than a restrictive sense.

Claims

1. A beam shaper, characterized in that: include: Unit 1; and Unit 2; wherein the first unit divides a first linear laser beam extending in a first direction into a plurality of beam segments, and deflects one or more of the plurality of beam segments to the second unit so that each of the plurality of beam segments is in a linear shape and aligned in a second direction orthogonal to the first direction; as well as The second unit uniformizes the plurality of beam segments to generate a second laser beam extending along the second direction.

2. The beam shaper according to claim 1, wherein: The first unit is a first prism array, the second unit is a second prism array, the first prism array and the second prism array form a prism array pair, and the second prism array compensates for the difference in propagation angles of the multiple light beam segments.

3. The beam shaper according to claim 1, wherein: The first unit is a first diffraction grating embedded on a first side of a substrate, and the second unit is a second diffraction grating embedded on a second side of the substrate.

4. The beam shaper according to claim 1, wherein: The divergence angle of the second laser beam in the first direction is smaller than that of the first linear laser beam, and the divergence angle of the second laser beam in the second direction is larger than that of the first linear laser beam.

5. The beam shaper according to claim 1, wherein: The first linear laser beam is emitted by a vertical cavity surface emitting laser array.

6. The beam shaper according to claim 1, wherein: The first direction is a fast axis direction, and the second direction is a slow axis direction.

7. The beam shaper according to claim 1, wherein: The first unit maintains a direction of at least one beam segment of the plurality of beam segments and deflects at least one of the one or more beam segments of the plurality of beam segments to each side of the at least one beam segment of the maintained direction.

8. The beam shaper according to claim 1, wherein: The multiple beam segments include an odd number of beam segments, and the first unit maintains the direction of the central beam segment unchanged, and deflects one or more beam segments located above the central beam segment downward to the right side or left side of the central beam segment, and deflects one or more beam segments located below the central beam segment upward to the left side or right side of the central beam segment.

9. A light detection and ranging (LiDAR) system, characterized in that: include: Beam shapers; The beam shaper includes a first unit and a second unit, wherein the first unit divides a first linear laser beam extending along a first direction into a plurality of beam segments, and deflects one or more of the plurality of beam segments to the second unit so that each of the plurality of beam segments is in a linear shape and aligned along a second direction orthogonal to the first direction, and the second unit homogenizes the plurality of beam segments to generate a second laser beam extending along the second direction.

10. The LiDAR system of claim 9, wherein: The first unit is a first prism array, the second unit is a second prism array, the first prism array and the second prism array form a prism array pair, and the second prism array compensates for the difference in propagation angles of the multiple light beam segments.

11. The LiDAR system of claim 9, wherein: The first unit is a first diffraction grating embedded on a first side of a substrate, and the second unit is a second diffraction grating embedded on a second side of the substrate.

12. The LiDAR system of claim 9, wherein: The divergence angle of the second laser beam in the first direction is smaller than that of the first linear laser beam, and the divergence angle of the second laser beam in the second direction is larger than that of the first linear laser beam.

13. The LiDAR system of claim 9, wherein: The first linear laser beam is emitted by a vertical cavity surface emitting laser array.

14. The LiDAR system of claim 9, wherein: The first direction is a fast axis direction, and the second direction is a slow axis direction.

15. The LiDAR system of claim 9, wherein: The first unit maintains a direction of at least one beam segment of the plurality of beam segments and deflects at least one of the one or more beam segments of the plurality of beam segments to each side of the at least one beam segment of the maintained direction.

16. The LiDAR system of claim 9, wherein the plurality of beam segments include an odd number of beam segments, and the first unit maintains the direction of a central beam segment unchanged, and deflects one or more beam segments located above the central beam segment downward to the right or left side of the central beam segment, and deflects one or more beam segments located below the central beam segment upward to the left or right side of the central beam segment.

17. A method for transforming a laser beam, characterized in that: include: receiving a linear laser beam from a lens at a first unit of a beam shaper, wherein the linear laser beam extends along a first direction; dividing the linear laser beam into a plurality of beam segments by the first unit of the beam shaper; deflecting, by the first unit of the beam shaper, one or more of the plurality of beam segments to a second unit such that each of the plurality of beam segments is linearly shaped and aligned along a second direction orthogonal to the first direction; and The plurality of beam segments are homogenized by the second unit to generate a second laser beam extending along the second direction.

18. The method of claim 17, wherein: The first unit is a first prism array, the second unit is a second prism array, the first prism array and the second prism array form a prism array pair, and the second prism array compensates for the difference in propagation angles of the multiple light beam segments.

19. The method of claim 17, wherein: The first unit is a first diffraction grating embedded on a first side of a substrate, and the second unit is a second diffraction grating embedded on a second side of the substrate.

20. The method of claim 17, wherein: The divergence angle of the second laser beam in the first direction is smaller than that of the first linear laser beam, and the divergence angle of the second laser beam in the second direction is larger than that of the first linear laser beam.

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