Laser beam splitting processing method and device

Abstract

The present invention relates to a laser beam splitting processing device, comprising a laser, a beam expansion device, a reflector, a spatial light modulator, a focusing lens, a beam splitting array module, a collimating lens module, a reflector array module and an F-Theta lens arranged in sequence. A laser beam splitting processing method of the present invention utilizes a spatial light modulator to generate multiple focal points, and at the same time, separates the multi-focal array in space through an innovatively designed micro-reflector array, thereby solving the problem that the diffraction angle of the spatial light modulator is small and the spacing of the generated beams is small. By placing a single lens on the path of each focus, it is ensured that the beam size will not increase as the beam spacing is enlarged while multiple beams are split at large spacing, and the size of the beam finally converged on the sample to be processed can be flexibly customized.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to a laser beam splitting processing method and device. Background Art

[0002] like Figure 5 , the prior art discloses a laser beam splitting processing device with application number CN202111643750.7, and provides a laser beam splitting processing device, which relates to the field of laser processing technology. The laser beam splitting processing device includes a laser, a diffraction beam splitter and an f-sinθ focusing lens group; the diffraction beam splitter receives the laser beam emitted by the laser and divides it into multiple sub-beams; the f-sinθ focusing lens group receives multiple sub-beams, focuses the sub-beams, and controls the position of the sub-beams on the focal plane; the sub-beams of each level output by the diffraction beam splitter satisfy the Bragg equation: 2dsinθ=mλ, and the f-sinθ focusing lens group satisfies the imaging relationship: h=f*sinθ, d is the period constant of the beam splitter, θ is the incident beam angle, m is the diffraction beam order, λ is the laser wavelength, and h is the focus spot position; f is the focal length of the f-sinθ focusing lens group. The device realizes precision multi-beam processing in the process of cooperating with the motor for processing, and maintains the distance between the focus spots of each sub-beam with good accuracy.

[0003] In the above patent, the diffraction beam splitter is a diffraction optical element and a programmable spatial light modulator, and the spacing adjustment module includes any one of a fixed-magnification lens group, a variable-magnification lens group or a programmable spatial light modulator. The disadvantage is that each sub-level beam output by the diffraction beam splitter satisfies the Bragg equation: 2dsinθ=mλ, and its period d is limited by the minimum physical size of the diffraction beam splitter, resulting in a small maximum limit diffraction angle θ of the beam. Within this limited diffraction angle, multiple beams are split, and the beam spacing becomes smaller as the number of splits increases. If a fixed-magnification lens group or a variable-magnification lens group is used to adjust the beam spacing, the adjustment range is limited, and while the beam spacing is multiplied, the spot size of each beam will also expand accordingly, making it difficult to obtain a multi-beam distribution with a small spot size and a large beam spacing, which is not conducive to laser processing.

[0004] Therefore, the present invention proposes a laser beam splitting processing method and device. Summary of the invention

[0005] The purpose of the present invention is to provide a laser beam splitting processing method and device. The present invention achieves three characteristics of multi-beam splitting: 1. multi-beam splitting; 2. large spacing between multiple beams; 3. small size of each beam in the multiple beams.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A laser beam splitting processing method comprises the following steps: laser is emitted from a laser 1, beam expanded by a beam expander 2, irradiated to a spatial light modulator 4 by a reflector 3, a hologram is loaded on the spatial light modulator 4, the hologram splits the light beam into an m×n array light beam, the light beam is converged on the focal plane of the condenser lens (5) after passing through a condenser lens 5, and an m×n dot matrix is ​​obtained, the dot matrix is ​​reflected or refracted by each micro-beam splitter on a beam splitting array module 6, wherein each micro-beam splitter on the beam splitting array module 6 is adjusted separately, so that the light beam dot matrix can be separated in space, the separated light beams are respectively passed through lenses in a collimating lens module 7, each light beam is collimated, each light beam after collimation is respectively irradiated to a reflector in a reflector array module 8, each light beam is reflected by the reflector, and enters an F-Theta lens 9 at different angles, and after being converged by the F-Theta lens 9, the multiple light beams are respectively converged on a sample 10 to be processed placed on a sample processing table 11.

[0008] After light field modulation by the spatial light modulator 4, the light beam is split into an m×n multi-beam array, and then converged by the focusing lens 5 to generate an m×n dot matrix at the focal plane of the focusing lens 5; since each micro-reflector is adjusted individually, the m×n multi-beam dot matrix can be separated by any angle to achieve multi-beams of arbitrary spacing.

[0009] A laser beam splitting processing device comprises a laser 1, a beam expander 2, a reflector 3, a spatial light modulator 4, a focusing lens 5, a beam splitting array module 6, a collimating lens module 7, a reflector array module 8 and an F-Theta lens 9 which are arranged in sequence.

[0010] The spatial light modulator 4 is any one of a liquid crystal spatial light modulator LCoS, a digital micromirror device DMD or a diffractive optical element DOE. At this time, due to the diffraction limit angle of the spatial light modulator, the spacing between the multiple light beams is small.

[0011] The beam splitting array module 6 comprises: a micro-mirror (601), a micro-mirror array substrate 602 and a micro-mirror adjustment rod 603; wherein each micro-mirror 601 is individually adjusted by two micro-mirror adjustment rods 603, and is fixedly connected to the micro-mirror array substrate 602 via the two micro-mirror adjustment rods 603.

[0012] The m×n multi-beam lattice converged by the beam splitting array module 6 can be separated in space by adjusting the reflection angle of each beam by each micro-reflector 601 .

[0013] In order for the single light beam reflected by the micro-reflector 601 to be collimated light when entering the F-Theta lens, it is necessary to add a single lens 701 in the light path of each beam after being reflected by the micro-lens array, and the distance from the focusing lens 5 to the micro-reflector 601 plus the distance from the micro-reflector 601 to the single lens 701 must be equal to the sum of the focal lengths of the focusing lens 5 and the single lens 701.

[0014] The condenser lens (5) and the single lens (701) form a 4f lens group. The diameter of the light beam before and after the lens group will be different according to the focal lengths of the condenser lens 5 and the single lens 701. The diameter of the light beam before and after incident on the 4f lens group satisfies the following relationship:

[0015]

[0016] It can be seen from the above formula that when the focal lengths of the focusing lens 5 and the single lens 701 are different, the beam diameter after the single lens 701 has three possibilities: maintaining the original beam diameter, reducing the beam diameter, and expanding the beam diameter.

[0017] After being reflected by the reflector, each light beam enters the F-Theta lens 9 at different angles. After being converged by the F-Theta lens 9, the multiple light beams are converged on the sample 10 to be processed placed on the sample processing table 11, and the spacing thereon satisfies:

[0018] Dx=f*θ

[0019] Wherein, Dx is the distance that the focus on the sample deviates from the center of the lens, f is the focal length of the F-Theta lens 9, and θ is the angle of incidence to the F-Theta lens 9.

[0020] The radius of the beam focused on the sample 10 to be processed satisfies the following formula:

[0021]

[0022] Where, λ is the wavelength of laser processing, f is the focal length of F-Theta lens 9, and w in is the radius of the beam incident on the F-Theta lens 9, w out is the radius of the beam focused on the sample.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention utilizes a spatial light modulator to generate multiple focal points, and through the innovative design of a micro-mirror array, the multi-focal array is separated in space, solving the problem that the diffraction angle of the spatial light modulator is small and the generated beam spacing is small. By placing a single lens on the path of each focus, it is ensured that the beam size will not increase as the beam spacing is enlarged while the large-spacing multi-beam splitting is performed, and the size of the beam that finally converges on the sample to be processed can be flexibly customized. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a laser beam splitting processing method and device of the present invention.

[0026] Figure 2 It is a schematic diagram of the m×n lattice of the present invention.

[0027] Figure 3 It is a schematic diagram of the m×n array reflector of the present invention.

[0028] Figure 4 This is a schematic diagram showing the principle of collimating a light beam using the collimating lens of the present invention.

[0029] Figure 1-4 In the figure: 1 is a laser, 2 is a beam expander, 3 is a reflector, 4 is a spatial light modulator, 5 is a focusing lens, 6 is a beam splitter array module, 7 is a collimating lens module, 8 is a reflector array module, 9 is an F-Theta lens, 10 is a sample to be processed, 11 is a sample processing table, 601 is a micro-mirror, 602 is a micro-mirror array substrate, and 603 is a micro-mirror adjustment rod.

[0030] Figure 5 A schematic diagram of a laser beam splitting processing device in the prior art, Figure 5 1 is a laser, 2 is a beam expander, 3 is a reflector, 4 is a diffraction beam splitter, 5 is a spacing adjustment module, and 6 is an f-sinθ lens group. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] A laser beam splitting processing method comprises the following steps:

[0033] like Figure 1As shown, laser light is emitted from a laser 1, and is expanded by a beam expander 2, and then irradiated to a spatial light modulator 4 through a reflector 3. A hologram is loaded on the spatial light modulator 4, and the hologram can divide the light beam into an m×n array light beam. After passing through a focusing lens 5, the light beam is converged at the focal plane of the focusing lens (5) to obtain an m×n dot matrix. The dot matrix is ​​reflected or refracted by each micro-beam splitter on a beam splitting array module 6, wherein each micro-beam splitter on the beam splitting array module 6 can be adjusted individually, so that the light beam dot matrix can be separated in space. After separation, the light beams are respectively passed through the lenses in a collimating lens module 7 to collimate each light beam. After collimation, each light beam is respectively irradiated to a reflector in a reflector array module 8. After being reflected by the reflector, each light beam enters an F-Theta lens 9 at different angles. After being converged by the F-Theta lens 9, the multiple light beams are respectively converged on a sample 10 to be processed placed on a sample processing table 11.

[0034] like Figure 2 As shown, after the light field modulation of the spatial light modulator 4, the light beam can be split into an m×n multi-beam array, and then converged by the focusing lens 5, and then an m×n dot matrix is ​​generated at the focal plane of the focusing lens 5. Among them, the spatial light modulator 4 can be any one of a liquid crystal spatial light modulator LCoS, a digital micromirror device DMD or a diffractive optical element DOE. At this time, limited by the diffraction limit angle of the spatial light modulator, the spacing between the multiple light beams is small.

[0035] A laser beam splitting processing device comprises a laser 1, a beam expander 2, a reflector 3, a spatial light modulator 4, a focusing lens 5, a beam splitting array module 6, a collimating lens module 7, a reflector array module 8, and an F-Theta lens 9, which are arranged in sequence. The beam splitting array module 6 is any one of a micro reflector array module and a micro refracting mirror array module.

[0036] The beam splitter array module 6 comprises: a micro-mirror (601), a micro-mirror array substrate 602 and a micro-mirror adjustment rod 603; wherein each micro-mirror 601 is individually adjusted by two micro-mirror adjustment rods 603, and is fixedly connected to the micro-mirror array substrate 602 via the two micro-mirror adjustment rods 603.

[0037] The m×n multi-beam lattice converged by the beam splitting array module 6 can be separated in space by adjusting the reflection angle of each beam by each micro-reflector 601 .

[0038] Since each micro-mirror can be adjusted individually, the m×n multi-beam lattice can be separated at any angle, thus realizing multi-beams with any spacing.

[0039] In order for the single light beam reflected by the micro-reflector 601 to be collimated light when entering the F-Theta lens, it is necessary to add a single lens 701 in the light path of each beam after being reflected by the micro-lens array, and the distance from the focusing lens 5 to the micro-reflector 601 plus the distance from the micro-reflector 601 to the single lens 701 must be equal to the sum of the focal lengths of the focusing lens 5 and the single lens 701.

[0040] As shown in Figure 4, the focusing lens (5) and the single lens (701) form a 4f lens group. The diameter of the light beam before and after this lens group will vary according to the focal lengths of the focusing lens 5 and the single lens 701. The diameter of the light beam before and after incident on the 4f lens group satisfies the following relationship:

[0041]

[0042] It can be seen from the above formula that when the focal lengths of the focusing lens 5 and the single lens 701 are different, the beam diameter after the single lens 701 can have three possibilities: maintaining the original beam diameter, reducing the beam diameter, and expanding the beam diameter. Therefore, this method can not only separate the adjustment of multiple beams, but also maintain the existing beam diameter size, and even customize the change of the beam diameter size.

[0043] After being reflected by the reflector, each light beam enters the F-Theta lens 9 at different angles. After being converged by the F-Theta lens 9, the multiple light beams are converged on the sample 10 to be processed placed on the sample processing table 11, and the spacing thereon satisfies:

[0044] Dx=f*θ

[0045] Wherein, Dx is the distance that the focus on the sample deviates from the center of the lens, f is the focal length of the F-Theta lens 9, and θ is the angle of incidence on the F-Theta lens 9. In addition, the radius of the beam focused on the sample 10 to be processed satisfies the following formula:

[0046]

[0047] Where, λ is the wavelength of laser processing, f is the focal length of F-Theta lens 9, and w in is the radius of the beam incident on the F-Theta lens 9, w out is the radius of the beam focused on the sample.

[0048] So far, the three characteristics of multi-beam splitting are completed:

[0049] 1.Multi-beam splitting;

[0050] 2. The spacing between multiple beams is large;

[0051] 3. Each beam in the multi-beam is smaller in size.

[0052] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only preferred examples of the invention and are not intended to limit the present invention. Without departing from the novel spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A laser beam splitting processing device, characterized in that The invention comprises a laser (1), a beam expansion device (2), a reflector (3), a spatial light modulator (4), a focusing lens (5), a beam splitting array module (6), a collimating lens module (7), a reflector array module (8) and an F-Theta lens (9) which are arranged in sequence; the spatial light modulator (4) is any one of a liquid crystal spatial light modulator (LCoS), a digital micromirror device (DMD) or a diffractive optical element (DOE); at this time, limited by the diffraction limit angle of the spatial light modulator, the spacing between the multiple light beams is small; the beam splitting array module (6) comprises: a micro reflector (601), a micro reflector array substrate (602) and a micro reflector adjustment rod (603); wherein Each micro-reflector (601) is individually adjusted by two micro-reflector adjustment rods (603), and is fixedly connected to the micro-reflector array substrate (602) through the two micro-reflector adjustment rods (603); the m×n multi-beam lattice converged by the light beam splitting array module (6) can be separated in space by adjusting the reflection angle of each beam of light by each micro-reflector (601); In order for the single light beam reflected by the micro-reflector (601) to be collimated light when entering the F-Theta lens, a single lens (701) needs to be added to the light path of each beam after being reflected by the micro-lens array, and the distance from the condenser lens (5) to the micro-reflector (601) plus the distance from the micro-reflector (601) to the single lens (701) must be equal to the sum of the focal lengths of the condenser lens (5) and the single lens (701); the condenser lens (5) and the single lens (701) form a 4f lens group, and the diameter of the light beam before and after the lens group will be different according to the different focal lengths of the condenser lens (5) and the single lens (701), and the diameter of the light beam before and after incident on the 4f lens group satisfies the following relationship: It can be seen from the above formula that when the focal lengths of the focusing lens (5) and the single lens (701) are different, the beam diameter after the single lens (701) has three possibilities: maintaining the original beam diameter, reducing the beam diameter, and expanding the beam diameter; after being reflected by the reflector, each beam enters the F-Theta lens (9) at different angles, and after being converged by the F-Theta lens (9), the multiple beams are converged on the sample to be processed (10) placed on the sample processing table (11), and the spacing thereon satisfies: Dx=f*θ Wherein, Dx is the distance that the focus on the sample deviates from the center of the lens, f is the focal length of the F-Theta lens (9), and θ is the angle of incidence on the F-Theta lens (9); the radius of the beam focused on the sample to be processed (10) satisfies the following formula: Where λ is the wavelength of the laser processing, f is the focal length of the F-Theta lens (9), and w in is the radius of the beam incident on the F-Theta lens (9), w out is the radius of the beam focused on the sample.

2. A laser beam splitting processing method using the laser beam splitting processing device according to claim 1, characterized in that: The method comprises the following steps: laser light is emitted from a laser (1), and is expanded by a beam expansion device (2), and then irradiated to a spatial light modulator (4) through a reflector (3), and a hologram is loaded on the spatial light modulator (4), and the hologram divides the light beam into m×n array light beams, and after passing through a focusing lens (5), the light beams are converged on the focal plane of the focusing lens (5) to obtain an m×n dot matrix, and the dot matrix is ​​reflected or refracted by each micro-beam splitter on a beam splitting array module (6), wherein each micro-beam splitter on the beam splitting array module (6) is adjusted separately, so that the light beam dot matrix can be separated in space, and the separated light beams are respectively passed through lenses in a collimating lens module (7), and each light beam is collimated. After being collimated, each light beam is irradiated onto a reflector in a reflector array module (8) respectively. After being reflected by the reflector, each light beam enters an F-Theta lens (9) at different angles respectively. After being converged by the F-Theta lens (9), the multiple light beams are converged onto a sample to be processed (10) placed on a sample processing table (11); after being modulated by the light field of the spatial light modulator (4), the light beams are split into an m×n multi-beam array, and then converged by a focusing lens (5), and then an m×n dot matrix is ​​generated at the focal plane of the focusing lens (5); since each micro-reflector is adjusted individually, the m×n multi-beam dot matrix can be separated by any angle to realize multi-beams with any spacing.

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