Uniform Bessel beam drilling device and method

Abstract

The invention discloses a uniform Bessel beam drilling device, and relates to the technical field of optical devices, the uniform Bessel beam drilling device mainly comprises a light generation device, a liquid crystal optical element and a regulation and control device, the light generation device is used for generating circularly polarized light and transmitting the circularly polarized light to the liquid crystal optical element; the arrangement mode of liquid crystal molecules in the liquid crystal optical element can be changed through the light-operated orientation technology, the liquid crystal optical element modulated through the light-operated orientation technology can receive circularly polarized light and form uniform Bessel light, and the liquid crystal optical element can have the function of a lens after being modulated through the light-operated orientation technology. Uniform Bessel light can be converged; the regulation and control device comprises a focusing optical element, and the focusing optical element can converge the uniform Bessel light emitted by the liquid crystal optical element again. The invention further discloses a uniform Bessel light drilling method which is implemented by adopting the uniform Bessel light beam drilling device, the energy utilization rate can be improved, the drilling effect is good, and the light path is simple.

Description

Technical Field

[0001] The invention relates to the technical field of optical devices, and in particular to a uniform Bessel beam drilling device and method. Background Art

[0002] Through Glass Via (TGV) is a technology for making vertical interconnect structures on glass substrates. TGV through holes are micro-vias with a diameter of usually 10μm-100μm. For various applications in the field of advanced packaging, tens of thousands of TGV through holes are usually required on each wafer and metallized to obtain the required conductivity. Glass pore-forming technology is one of the main difficulties restricting the development of TGV. The preparation of TGV through holes needs to meet a series of requirements such as high speed, high precision, narrow pitch, smooth sidewalls, good verticality and low cost. How to prepare glass micro-holes with high aspect ratio, narrow pitch, high verticality, high sidewall roughness and low cost has been the focus of various research work for many years.

[0003] The increasing demand for bandwidth in high-performance computing, 5G communications, and IoT applications has driven the migration of TGV technology to 2.5D and 3D interposers, which requires lower high-frequency losses and a larger hole depth to via diameter ratio to achieve vertical interconnection, which in turn requires high aspect ratio TGVs. In addition, a large number of closely positioned vias (high-density vias) are required. Given the demand for large-area and high-density vias on glass panels, the space occupied by each via must be minimized in order to maximize space utilization.

[0004] Traditional Bessel beams are well-known for their non-diffraction and self-healing properties. The light field of traditional Bessel beams will not be distorted by diffraction effects, while the light spot of traditional Gaussian beams will diverge rapidly. The extremely high aspect ratio of traditional Bessel beams makes them widely used in laser TGV drilling. However, due to the different axial intensity distribution of traditional Bessel beams, the energy of the central main lobe is concentrated at the entrance of the hole, which makes the material removal rate here faster; and as the drilling depth increases, the change in the intensity of the central main lobe and the influence of the energy of the surrounding secondary lobes make the energy absorption and material removal rate at different positions of the hole wall different. The amount of material removed near the center and edge of the hole is inconsistent, resulting in a certain inclination of the hole wall, resulting in a taper, and high verticality cannot be guaranteed, which will cause a waste of resources and energy. Therefore, a uniform Bessel beam drilling device and method are urgently needed to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a uniform Bessel beam drilling device and method to solve the problems existing in the above-mentioned prior art, which can improve energy utilization, have good drilling effect, and have a simple optical path.

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

[0007] The present invention provides a uniform Bessel beam drilling device, comprising a light generating device, a liquid crystal optical element and a regulating device.

[0008] The light generating device is used to generate circularly polarized light and transmit it to the liquid crystal optical element;

[0009] The arrangement of liquid crystal molecules in the liquid crystal optical element can be changed by a light-controlled orientation technology, wherein the liquid crystal optical element can receive the circularly polarized light and form uniform Bessel light after being modulated by the light-controlled orientation technology, and the liquid crystal optical element can have a lens function after being modulated by the light-controlled orientation technology, and can converge the uniform Bessel light;

[0010] The regulating device comprises a focusing optical element, and the focusing optical element is used to receive the uniform Bessel light emitted by the liquid crystal optical element and can converge the uniform Bessel light emitted by the liquid crystal optical element again.

[0011] In some embodiments, the light generating device includes a radiation device and a polarization adjustment device, and the radiation device, the polarization adjustment device and the liquid crystal optical element are arranged in sequence in the direction of light propagation, the radiation device is used to transmit light to the polarization adjustment device, and the polarization adjustment device can adjust the polarization direction of the light transmitted by the radiation device.

[0012] In some embodiments, the radiation device is a laser, which can generate linearly polarized laser light and input the linearly polarized laser light into the polarization adjustment device; the polarization adjustment device includes a quarter wave plate, and the fast axis direction of the quarter wave plate forms an angle of -45° with the polarization direction of the linearly polarized laser light.

[0013] In some embodiments, the quarter wave plate is a polymer true zero-order quarter wave plate, and the polymer true zero-order quarter wave plate includes a glass substrate layer and a liquid crystal polymer functional film layer sequentially arranged in the direction of light propagation.

[0014] In some embodiments, the polymer true zero-order quarter-wave plate is bonded to the liquid crystal optical element.

[0015] In some embodiments, a rotating mount is further included, wherein the quarter wave plate and the liquid crystal optical element are sequentially arranged inside the rotating mount in the direction of light propagation, and the rotating mount can drive the quarter wave plate and the liquid crystal optical element to rotate to adjust the angle between the fast axis direction of the quarter wave plate and the polarization direction of the linearly polarized laser.

[0016] In some embodiments, a transfer module is further included, one end of which is connected to the end of the rotating mount, and the other end of which is connected to the head end of the focusing optical element, and the length of the transfer module can be changed.

[0017] In some embodiments, the adapter module is a metal sleeve, and the diffraction-free distance of the uniform Bessel light beam and the diameter of the main lobe of the focusing spot can be changed by changing the length of the metal sleeve.

[0018] In some embodiments, the focusing optical element includes an objective lens, which is disposed at the end of the liquid crystal optical element and can receive the uniform Bessel light emitted by the liquid crystal optical element. The focusing position of the uniform Bessel light beam and the spot diameter at the focusing point can be changed by changing the focal length of the objective lens, wherein the objective lens is a high-power laser objective lens with a magnification of not less than 5 times.

[0019] The present invention also provides a method for uniform Bessel light drilling, which is implemented using the uniform Bessel light beam drilling device as described above, and includes the following steps:

[0020] S1: Based on the phase distribution required to generate uniform Bessel light and realize the lens function, the azimuth angle of the liquid crystal molecules is calculated, and the liquid crystal molecules in the liquid crystal optical element are modulated by light-controlled orientation technology;

[0021] S2: Arrange the light generating device, the modulated liquid crystal optical element and the regulating device in sequence, so that light can be focused on the workpiece after passing through the light generating device, the modulated liquid crystal optical element and the regulating device in sequence.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] The uniform Bessel beam drilling device provided by the present invention includes a light generating device, a liquid crystal optical element and a control device, wherein the light generating device is used to generate circularly polarized light and transmit it to the liquid crystal optical element; the arrangement mode of the liquid crystal molecules in the liquid crystal optical element can be changed by the light control orientation technology, wherein the liquid crystal optical element modulated by the light control orientation technology can receive circularly polarized light and form uniform Bessel light, and the liquid crystal optical element can have the function of a lens after being modulated by the light control orientation technology, and can converge the uniform Bessel light; the liquid crystal optical element has the function of a lens after phase modulation, which can not only generate uniform Bessel light, but also converge it, thereby simplifying the structure of the optical system. Compared with the traditional method that requires multiple optical elements to realize beam generation and focusing respectively, the optical path has one less element that is sensitive to coaxiality tolerance, and the coaxiality tolerance of the entire optical path will also be reduced, thereby improving the stability and reliability of the system. Moreover, the phase of the liquid crystal optical element made of liquid crystal material is a quasi-continuous phase, which is approximately a continuous phase, so the diffraction efficiency is high, the energy utilization rate is high, the cost is low and the delivery time is short. The axial energy intensity of the uniform Bessel beam is evenly distributed, which reduces the taper of the hole, ensures high verticality, saves resources, and the energy of the uniform Bessel beam is effectively distributed in the processing area, which can maximize energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of a uniform Bessel beam drilling device in some embodiments of the present invention;

[0026] Figure 2 FIG. 1 is a light path diagram of a uniform Bessel beam drilling device in some embodiments of the present invention.

[0027] In the figure: 1-polymer true zero-order quarter-wave plate; 2-liquid crystal optical element; 3-objective lens; 4-rotating mount; 5-metal sleeve. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The purpose of the present invention is to provide a uniform Bessel beam drilling device and method to solve the problems existing in the prior art, improve energy utilization, achieve good drilling effect, and have a simple optical path and convenient regulation.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Embodiment 1

[0032] like Figure 1-Figure 2 As shown, the present invention provides a uniform Bessel beam drilling device, including a light generating device, a liquid crystal optical element 2 and a control device, wherein the light generating device is used to generate circularly polarized light and transmit it to the liquid crystal optical element 2; the arrangement mode of the liquid crystal molecules in the liquid crystal optical element 2 can be changed by the light control orientation technology, wherein the liquid crystal optical element 2 modulated by the light control orientation technology can receive the circularly polarized light and form uniform Bessel light, wherein the uniform Bessel light here is the Bessel light with uniform axial intensity distribution, and the liquid crystal optical element can have the function of a lens after being modulated by the light control orientation technology, and can converge the uniform Bessel light, specifically, the phase of the lens is directly superimposed with the phase of the uniform Bessel light generating element to obtain the liquid crystal optical element of this embodiment; the control device includes a focusing optical element, which is arranged at the end of the liquid crystal optical element 2, and the focusing optical element can converge the uniform Bessel light emitted by the liquid crystal optical element 2 again. The liquid crystal optical element 2 has the function of a lens after phase modulation, and can not only generate uniform Bessel light, but also converge it, thereby simplifying the structure of the optical system. Compared with the traditional method that requires multiple optical elements to realize beam generation and focusing respectively, the optical path has one less element that is sensitive to coaxiality tolerance, and the coaxiality tolerance of the entire optical path will also be reduced, improving the stability and reliability of the system. In addition, the phase of the liquid crystal optical element 2 made of liquid crystal material is quasi-continuous phase, which is close to continuous phase, so the diffraction efficiency is high, the energy utilization rate is high, the cost is low and the delivery time is short. The axial energy intensity of the uniform Bessel beam is evenly distributed, which reduces the taper of the hole, ensures high verticality, saves resources, and the energy of the uniform Bessel beam is effectively distributed in the processing area, which can maximize the energy utilization rate.

[0033] It should be noted that liquid crystal has large birefringence and high transmittance. The liquid crystal optical element 2 based on geometric phase can be manufactured by light-controlled orientation technology, and the liquid crystal molecules in the liquid crystal optical element 2 are arranged as needed by light-controlled orientation technology, so that the arrangement of the liquid crystal molecules is uniform and arranged at a certain angle. And the light-controlled orientation technology has high orientation accuracy and simple manufacturing process. The liquid crystal optical element 2 made of liquid crystal material can achieve continuous phase and high transmittance, has high diffraction efficiency, low cost and easy manufacturing process, and provides a wider range of application possibilities for generating uniform Bessel light. Moreover, the phase of the liquid crystal optical element 2 of this embodiment is the result of iterative optimization of the phase of the diffraction type flat cone lens. There are roughly three existing manufacturing implementation methods of the liquid crystal optical element 2, namely, etching process manufacturing, spatial light modulator manufacturing and liquid crystal light-controlled orientation technology manufacturing of this embodiment. The phase order of the liquid crystal optical element 2 manufactured by the etching process is generally less than or equal to 16 orders (the higher the order, the higher the cost), and the phase of the liquid crystal optical element 2 manufactured by the liquid crystal light-controlled orientation technology of this embodiment is a quasi-continuous phase, which is approximately a continuous phase, so the diffraction efficiency is high, the energy utilization rate is high, the cost is lower than the etching process and the delivery time is short. Moreover, the etching process cannot comprehensively regulate the phase of the lens and the phase of the liquid crystal optical element 2. The uniform Bessel homogenized diffraction optical element phase loaded by the spatial light modulator can also realize a uniform Bessel beam, but in the actual processing light path, in order to avoid the influence of the zero-order diffraction light, other elements will be added to deviate from the zero-order diffraction light, which makes the light path complicated, and among the three uniform Bessel beam implementation methods, the spatial light modulator has the highest cost. Specifically, the generation of a uniform Bessel beam in this embodiment is based on an iterative optimization method, and a Bessel beam with limited focal extension and axial uniform intensity distribution, that is, a uniform Bessel beam, is designed through a design and fine-tuning process. Starting from the standard flat conical lens axial phase mask, the design process uses a genetic algorithm (GA) as optimization feedback in the iterative optimization process to find the optimal radial phase distribution, thereby generating a Bessel beam with a desired axial uniform intensity distribution.

[0034] In some embodiments, the light generating device includes a ray device and a polarization adjusting device, one end of the polarization adjusting device is aligned with the ray device in the direction of light propagation, and the other end is aligned with the liquid crystal optical element in the direction of light propagation, the ray device is used to transmit light to the polarization adjusting device, and the polarization adjusting device is used to adjust the polarization direction of the light transmitted by the ray device. Specifically, the polarization adjusting device includes a quarter wave plate, and the fast axis direction of the quarter wave plate is at an angle of -45° with the polarization direction of the light. After the linearly polarized light passes through the quarter wave plate, it will be decomposed into ordinary light (o light) and extraordinary light (e light). When the polarization direction of the linearly polarized laser is 45 degrees to the fast axis direction of the quarter wave plate, the amplitudes of the o light and the e light are equal. After passing through the quarter wave plate, due to the different propagation speeds of the o light and the e light in the wave plate, a certain phase difference will be generated. When this phase difference is one quarter wavelength, the linearly polarized light will be converted into circularly polarized light. The fast axis direction of the quarter wave plate is 45 degrees clockwise to the polarization direction of the linearly polarized laser, that is, -45°, and the emitted light will be left-handed circularly polarized light. The rotating electric field of the left-handed circularly polarized light is matched with the liquid crystal optical element 2 of the liquid crystal optical element to make the axial intensity of the Bessel beam evenly distributed, thereby maximizing the energy utilization and resource utilization.

[0035] In some embodiments, the radiation device is a laser, which can generate linearly polarized laser light and input the linearly polarized laser light into the polarization adjustment device. As a radiation device, the laser can provide highly stable linearly polarized light output. Compared with traditional light sources, the laser has the characteristics of narrow line width, high brightness and good coherence, which makes the generated linearly polarized light more stable and reliable.

[0036] It should be noted that the ray device can also be of other types, such as using a traditional light source with a polarizer to produce a linearly polarized laser, but this method is more complicated to produce a linearly polarized laser, and the stability is not as good as the linearly polarized laser produced by a laser. More importantly, when the polarizer is set, the power loss of light passing through the polarizer is very serious, affecting subsequent processing operations.

[0037] In some embodiments, the quarter wave plate is a polymer true zero-order quarter wave plate 1, and the polymer true zero-order quarter wave plate 1 includes a glass substrate layer and a liquid crystal polymer functional film layer arranged in sequence. The polymer true zero-order quarter wave plate 1 has a high tolerance to the angle of incident light, and even if the angle of the incident light has a certain deviation, the polymer true zero-order quarter wave plate 1 can still effectively achieve polarization conversion.

[0038] It should be noted that a quarter wave plate can also be used as a zero-order quarter wave plate if the requirements for use are met. However, the performance of a zero-order quarter wave plate is inferior to that of a polymer true zero-order quarter wave plate 1. For example, the zero-order wave plate has relatively strict requirements on the angle of the incident light. When the angle of the incident light exceeds a certain range, its polarization conversion effect will be significantly affected.

[0039] As a preferred embodiment, the polymer true zero-order quarter wave plate 1 includes a glass substrate layer and a liquid crystal polymer functional film layer which are arranged in sequence. The two-layer structure is glued and bonded in sequence, which can combine the advantages of different materials, reduce the overall birefringence non-uniformity, and the polymer true zero-order quarter wave plate 1 produced by gluing can enhance the overall mechanical strength by gluing a thin crystal material (liquid crystal polymer functional film layer) on a solid substrate (glass substrate layer).

[0040] It should be noted that the quarter-wave plate can also be a true zero-order quarter-wave plate made of a single piece. The single-piece true zero-order quarter-wave plate is made of only one piece of quartz material. The selection and processing requirements of the quartz material are very high, and the thickness and uniformity of the quartz plate need to be precisely controlled to ensure that it can accurately produce a quarter-wavelength phase delay. However, the wave plate made of a single piece may have uneven birefringence inside the material, which will affect the polarization conversion effect of the wave plate on light. In addition, the wave plate made of a single piece may be easily damaged by external forces during use due to the brittleness or thickness limitation of the material.

[0041] In some embodiments, the polymer true zero-order quarter-wave plate 1 is bonded to the liquid crystal optical element 2, specifically, the liquid crystal polymer functional film layer is bonded to the liquid crystal optical element 2, that is, the two sides of the liquid crystal polymer functional film layer are bonded to the glass substrate layer and the liquid crystal optical element 2 respectively. The main function of the quarter-wave plate is to convert linear polarized light into circular polarized light. When bonded to the liquid crystal optical element 2, the polarization state of the light beam can be more accurately controlled to ensure that the light entering the liquid crystal optical element 2 is in a suitable polarization state, thereby making the generation of uniform Bessel light more stable and accurate, which is conducive to improving the performance of the entire optical system and the accuracy of drilling holes. The optical path is streamlined, and the bonding setting can effectively save space in the optical system and make the entire device more compact. In some application scenarios with high space requirements, such as miniaturized processing equipment or portable optical instruments, the compact structural design can improve the integration of the device, facilitate installation and use, and also help to reduce the overall weight of the device, reduce the difficulty of optical path debugging, and save costs and processing space.

[0042] In some embodiments, the uniform Bessel beam drilling device also includes a rotating mount 4, and the quarter wave plate and the liquid crystal optical element 2 are sequentially arranged inside the rotating mount 4. The rotating mount 4 can drive the quarter wave plate and the liquid crystal optical element 2 to rotate to adjust the angle between the fast axis direction of the quarter wave plate and the polarization direction of the linearly polarized laser.

[0043] The quarter wave plate is fixedly mounted on the rotating mount 4, and the rotating mount 4 can drive the quarter wave plate to rotate to change the fast axis direction of the quarter wave plate. The quarter wave plate is fixed on the rotating mount 4, and the angle of the quarter wave plate relative to the incident light can be accurately adjusted by rotating the mount 4. Since the change of the polarization state of the light by the quarter wave plate depends on the angle between its optical axis and the polarization direction of the incident light, the polarization state of the light can be accurately adjusted from linear polarized light to circular polarized light, elliptically polarized light and linear polarized light of different polarization directions by rotating the mount 4, and the adaptability is wider. At the same time, the quarter wave plate is fixedly mounted on the rotating mount 4, which can ensure the stability of the wave plate during the adjustment process. Moreover, since the polymer true zero-order quarter wave plate 1 is fitted with the liquid crystal optical element 2, the liquid crystal optical element 2 can be adjusted together when adjusting the polymer true zero-order quarter wave plate 1, and there is no need to adjust it separately, which saves time.

[0044] In some embodiments, the uniform Bessel beam drilling device further includes an adapter module, one end of which is arranged at the end of the rotating mounting seat 4, and the other end is arranged at the head end of the focusing optical element. The length of the adapter module can be changed. Preferably, the adapter module is a metal sleeve 5. By changing the length of the metal sleeve 5, the diffraction-free distance of the uniform Bessel beam and the diameter of the main lobe of the focused light spot can be changed. When drilling thicker materials, the length of the metal sleeve 5 can be reduced to increase the diffraction-free distance, ensure that the stability and focusing effect of the beam can be maintained deep in the material, and achieve high-quality deep hole processing. For drilling thinner materials, the length of the sleeve can be increased to accurately control the range of the beam and avoid unnecessary damage to other parts of the material. When high-precision fine drilling is required, the length of the metal sleeve 5 is increased to reduce the diameter of the main lobe of the focused light spot, thereby improving the accuracy of drilling and drilling smaller and more precise holes. If the drilling efficiency is to be improved, the length of the sleeve can be appropriately reduced, the diameter of the main lobe of the light spot can be increased, and the amount of material removed in a single drilling can be increased.

[0045] In some embodiments, the focusing optical element includes an objective lens 3, and the objective lens 3 is aligned with the end of the liquid crystal optical element. By changing the focal length of the objective lens 3, the non-diffraction distance (i.e., air focal depth) of the uniform Bessel light beam can be changed. Zmax2 essentially changes the focus position of the uniform Bessel light beam, and can also change the diameter of the main lobe of the focused light spot, which is essentially the drilling diameter of the light spot. When high-precision micro-hole processing is required, the focal length of the objective lens 3 is reduced to reduce the diameter of the main lobe of the focused light spot, thereby drilling finer holes to meet the requirements of micro-aperture and high precision in fields such as electronic chip manufacturing. On the contrary, when the drilling precision requirement is relatively low but a larger aperture is required, the focal length of the objective lens 3 is increased, the main lobe diameter of the focused light spot is enlarged, and the drilling efficiency is improved.

[0046] In some embodiments, the objective lens 3 is a high-power laser objective lens with a magnification of not less than 5 times. The high magnification enables the objective lens 3 to focus the light beam to a very small area, thereby achieving high-precision microstructure processing. In the field of electronic manufacturing, such as etching of fine circuits in semiconductor chip manufacturing, the objective lens 3 with a magnification of not less than 5 times can ensure that the light beam is accurately focused and drills tiny holes with precise size and neat edges, thus meeting the requirements of high-precision processing for miniaturization and integration of electronic components.

[0047] It should also be noted that the uniform Bessel beam drilling device of this embodiment has a relatively high damage threshold in experimental tests of the light source parameters: repetition rate 50KHz, incident spot size 6mm(e-2), pulse width <12ps, single pulse energy 600μJ.

[0048] Embodiment 2

[0049] This embodiment provides a method for uniform Bessel light drilling, which is implemented using the uniform Bessel light beam drilling device as described in the first embodiment, and includes the following steps:

[0050] S1: Based on the phase distribution required to generate uniform Bessel light and realize the lens function, the azimuth angle of the liquid crystal molecules is calculated, and the liquid crystal molecules in the liquid crystal optical element are modulated by light-controlled orientation technology;

[0051] S2: Arrange the light generating device, the modulated liquid crystal optical element and the regulating device in sequence, so that light can be focused on the workpiece after passing through the light generating device, the modulated liquid crystal optical element and the regulating device in sequence.

[0052] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A uniform Bessel beam drilling device, characterized in that: It includes a light generating device, a liquid crystal optical element and a control device, The light generating device is used to generate circularly polarized light and transmit it to the liquid crystal optical element; The arrangement of liquid crystal molecules in the liquid crystal optical element can be changed by a light-controlled orientation technology, wherein the liquid crystal optical element can receive the circularly polarized light and form uniform Bessel light after being modulated by the light-controlled orientation technology, and the liquid crystal optical element can have a lens function after being modulated by the light-controlled orientation technology, and can converge the uniform Bessel light; The regulating device comprises a focusing optical element, and the focusing optical element is used to receive the uniform Bessel light emitted by the liquid crystal optical element and can converge the uniform Bessel light emitted by the liquid crystal optical element again.

2. The uniform Bessel beam drilling device according to claim 1, characterized in that: The light generating device includes a radiation device and a polarization adjusting device. The radiation device, the polarization adjusting device and the liquid crystal optical element are arranged in sequence in the direction of light propagation. The radiation device is used to transmit light to the polarization adjusting device, and the polarization adjusting device can adjust the polarization direction of the light transmitted by the radiation device.

3. The uniform Bessel beam drilling device according to claim 2, characterized in that: The ray device is a laser, which can generate linearly polarized laser light and input the linearly polarized laser light into the polarization adjustment device; the polarization adjustment device includes a quarter wave plate, and the fast axis direction of the quarter wave plate forms an angle of -45° with the polarization direction of the linearly polarized laser light.

4. The uniform Bessel beam drilling device according to claim 3, characterized in that: The quarter wave plate is a polymer true zero-order quarter wave plate, which comprises a glass substrate layer and a liquid crystal polymer functional film layer which are sequentially arranged in the direction of light propagation.

5. The uniform Bessel beam drilling device according to claim 4, characterized in that: The polymer true zero-order quarter-wave plate is bonded to the liquid crystal optical element.

6. The uniform Bessel beam drilling device according to claim 3, characterized in that: It also includes a rotating mount, wherein the quarter wave plate and the liquid crystal optical element are sequentially arranged inside the rotating mount in the direction of light propagation, and the rotating mount can drive the quarter wave plate and the liquid crystal optical element to rotate to adjust the angle between the fast axis direction of the quarter wave plate and the polarization direction of the linearly polarized laser.

7. The uniform Bessel beam drilling device according to claim 6, characterized in that: It also includes a switching module, one end of which is connected to the end of the rotating mounting seat, and the other end of which is connected to the head end of the focusing optical element, and the length of the switching module can be changed.

8. The uniform Bessel beam drilling device according to claim 7, characterized in that: The adapter module is a metal sleeve, and the diffraction-free distance of the uniform Bessel light beam and the diameter of the main lobe of the focusing spot can be changed by changing the length of the metal sleeve.

9. The uniform Bessel beam drilling device according to claim 1, characterized in that: The focusing optical element includes an objective lens, which is arranged at the end of the liquid crystal optical element and can receive the uniform Bessel light emitted by the liquid crystal optical element. The focusing position of the uniform Bessel light beam and the spot diameter at the focusing point can be changed by changing the focal length of the objective lens, wherein the objective lens is a high-power laser objective lens with a magnification of not less than 5 times.

10. A method for uniform Bessel light drilling, characterized in that: The uniform Bessel beam drilling device according to any one of claims 1 to 9 is implemented, comprising the steps of: S1: Based on the phase distribution required to generate uniform Bessel light and realize the lens function, the azimuth angle of the liquid crystal molecules is calculated, and the liquid crystal molecules in the liquid crystal optical element are modulated by light-controlled orientation technology; S2: Arrange the light generating device, the modulated liquid crystal optical element and the regulating device in sequence, so that light can be focused on the workpiece after passing through the light generating device, the modulated liquid crystal optical element and the regulating device in sequence.

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