Laser scanning processing system for micropore with large depth-diameter ratio

Abstract

The utility model discloses a laser scanning processing system for a micropore with a large depth-diameter ratio, which comprises a laser, an adjustable beam expander, a conical lens, a focus lens and a scanning galvanometer which are sequentially arranged from front to back, and a compensating mirror group is arranged on one side, facing a processed sample, of the scanning galvanometer; laser emitted by the laser device can generate a Bessel beam through the conical lens, the Bessel beam sequentially passes through the focus lens, the scanning galvanometer and the compensation lens set, and the focus lens and the compensation lens set can compress the Bessel beam and transfer the compressed Bessel beam to the position above a machined sample. And the scanning galvanometer controls the Bessel beam to scan and cut micropores in various shapes on the surface of the processed sample. Bessel beams and a scanning galvanometer scanning system are integrated together, a displacement table does not need to be moved, scanning machining is conducted through a scanning galvanometer, the machining precision and efficiency are greatly improved, and the flexibility is also greatly improved; compared with traditional laser drilling, the Bessel beam can be better suitable for machining of micropores with the large depth-diameter ratio.

Description

Technical Field

[0001] The utility model relates to the technical field of laser processing, in particular to a laser scanning processing system for micro-holes with a large aspect ratio. Background Art

[0002] Microhole processing is an important step in the manufacture of microdevices. Ultrafast lasers are widely used in microhole processing of transparent, hard and brittle materials due to their nonlinear absorption and "cold processing" characteristics. The commonly used method is to focus the ultrafast laser inside the transparent material, use the ultra-high peak energy of the beam to ablate the material, and at the same time use an auxiliary displacement device to control the movement of the laser focus up and down inside the material to process micron-scale microholes. The aspect ratio and hole wall quality of the microholes processed by the above method are restricted by factors such as laser parameters, drilling speed, and ablation debris, making it difficult to achieve further improvement. In addition, there is a problem of large movement restrictions on the moving stage, which affects efficiency. Utility Model Content

[0003] In view of the defects of the above-mentioned prior art, the present invention aims to provide a laser scanning processing system for micro-holes with a large aspect ratio, which does not require a moving translation stage, relies on scanning galvanometers for scanning processing, and can improve processing efficiency.

[0004] In order to solve the above technical problems, the utility model adopts the following technical solutions: a laser scanning processing system for microholes with a large aspect ratio, comprising a laser, an adjustable beam expander, a conical lens, a focusing mirror and a scanning galvanometer mirror arranged in sequence from front to back, and a compensation mirror group is provided on the side of the scanning galvanometer mirror facing the processing sample; the laser emitted by the laser can generate a Bessel beam through the conical lens, and the Bessel beam passes through the focusing mirror, the scanning galvanometer mirror, and the compensation mirror group in sequence. The focusing mirror and the compensation mirror group can compress the Bessel beam and transfer it to the top of the processing sample, and the Bessel beam controlled by the scanning galvanometer mirror can scan and cut microholes of various shapes on the surface of the processing sample.

[0005] Preferably, a reflector is provided in the scanning galvanometer, and the reflector is close to the real focal plane existing near the focal plane of the focusing mirror, ensuring the telecentricity of the Bessel beam, so that the Bessel beam can maintain a high beam quality during propagation and avoid beam diffusion and deformation.

[0006] Preferably, the compensation lens group is a lens group including 2 to 3 spherical lenses or aspherical lenses, which can realize the compression of the Bessel light beam in cooperation with the focusing lens.

[0007] Preferably, the scanning galvanometer controls the Bessel light beam to scan the surface of the processed sample in a telecentric manner, which is applicable to the processing of various straight holes with vertical side walls.

[0008] Preferably, the laser, adjustable beam expander, aconic lens, focusing mirror and scanning galvanometer are arranged in the same plane.

[0009] The beneficial effects of the present invention are as follows: by integrating the Bessel beam and the scanning galvanometer scanning system together, there is no need to move the translation stage, and the processing is performed by scanning with the scanning galvanometer, which greatly improves the processing accuracy and efficiency, and also greatly improves the flexibility; compared with traditional laser drilling, the Bessel beam is better suitable for micro-hole processing with a large aspect ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram of the utility model;

[0011] In the figure: 1-laser, 2-adjustable beam expander, 3-conical lens, 4-focusing mirror, 5-scanning galvanometer, 6-compensation mirror group, 7-processing sample. DETAILED DESCRIPTION

[0012] In order to better understand the improvements made by the present invention relative to the prior art, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0013] like Figure 1 As shown, a laser scanning processing system for microholes with a large aspect ratio is mainly composed of a laser 1, an adjustable beam expander 2, a conical lens 3, a focusing mirror 4 and a scanning galvanometer 5 arranged in sequence from front to back, and the laser 1, the adjustable beam expander 2, the conical lens 3, the focusing mirror 4 and the scanning galvanometer 5 are arranged in the same plane along the optical path, and a compensation mirror group 6 is provided on the side of the scanning galvanometer 5 facing the processing sample 7.

[0014] The laser emitted by laser 1 generates a Bessel beam through the conical lens 3. The Bessel beam with a long focal depth is suitable for processing structures with a large aspect ratio. The energy of the Bessel beam remains basically unchanged during the transmission process, which is suitable for application scenarios requiring deep cutting and uniform energy distribution, thereby improving processing accuracy.

[0015] The Bessel beam passes through the focusing mirror 4, the scanning galvanometer 5, and the compensation mirror group 6 in sequence. The focusing mirror 4 and the compensation mirror group 6 compress the Bessel beam and transfer it to the top of the processing sample 7, and the scanning galvanometer 5 controls the Bessel beam to scan and cut microholes of various shapes on the surface of the processing sample 7. The scanning galvanometer 5 controls the scanning of the Bessel beam on the surface of the processing sample 7 to be telecentric scanning, which is suitable for the processing of various straight holes with vertical side walls.

[0016] In this system, a real focal plane exists near the focal plane of focusing mirror 4. The reflector installed within scanning galvanometer 5 ensures the telecentricity of the Bessel beam, allowing the Bessel beam to maintain high beam quality during propagation and avoiding beam diffusion and deformation. To further ensure that the laser beam maintains the Bessel energy distribution when scanning off-axis and the corresponding scanning range can reach φ2mm, the lens of compensation lens group 6 can compensate for off-axis aberrations within the small scanning angle range of 0 to 2° of the scanning galvanometer. The compensation lens group 6 is a lens group, typically composed of two to three spherical or aspherical lenses, which cooperates with focusing mirror 4 to achieve Bessel beam compression.

[0017] The system operates according to the following principles: Laser light emitted by laser 1 passes through an adjustable beam expander 2, which adjusts the beam diameter and divergence as needed. This converts the laser beam into a collimated beam during laser processing. The collimated beam then travels forward along the optical path through an axicon 3, which focuses the collimated beam into a ring-shaped beam, generating a Bessel beam. The Bessel beam then passes through a focusing lens 4, significantly increasing the intensity of the central bright spot while compressing the sidebands. The compressed Bessel beam then passes through a scanning galvanometer 5, where it is angled to facilitate scanning the surface of the sample 7 and cutting microholes of various shapes. The scanning galvanometer 5 typically reflects the laser light through two galvanometer mirrors, generating XY motion to achieve precise laser processing. The galvanometer motor, when fed a position signal, oscillates the beam at a specific angle according to a voltage-to-angle conversion ratio. After the Bessel beam is angled, a compensating lens 6 compensates for optical path differences, ensuring optical path stability and accuracy. This is particularly important during cutting operations, particularly for adjusting and stabilizing the focus position to prevent degradation in cutting quality.

[0018] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A laser scanning processing system for micro-holes with a large aspect ratio, characterized by: The invention comprises a laser (1), an adjustable beam expander (2), a conical lens (3), a focusing lens (4) and a scanning galvanometer (5) which are arranged in sequence from front to back. A compensation lens group (6) is provided on the side of the scanning galvanometer (5) facing the processing sample (7). The laser light emitted by the laser (1) can generate a Bessel beam through the conical lens (3). The Bessel beam passes through the focusing lens (4), the scanning galvanometer (5) and the compensation lens group (6) in sequence. The focusing lens (4) and the compensation lens group (6) can compress the Bessel beam and transfer it to the top of the processing sample (7). The scanning galvanometer (5) controls the Bessel beam to scan and cut microholes of various shapes on the surface of the processing sample (7).

2. The laser scanning processing system for high aspect ratio micro-holes according to claim 1, characterized in that: A reflecting mirror is provided inside the scanning galvanometer (5), and the reflecting mirror is close to a real focal plane existing near the focal plane of the focusing mirror (4).

3. The laser scanning processing system for micro-holes with a large aspect ratio according to claim 1, characterized in that: The compensation lens group (6) is a lens group including 2 to 3 spherical lenses or aspherical lenses.

4. The laser scanning processing system for high aspect ratio micro-holes according to claim 1, characterized in that: The scanning galvanometer (5) controls the Bessel light beam to scan the surface of the processed sample (7) in a telecentric manner.

5. The laser scanning processing system for micro-holes with a large aspect ratio according to claim 1, characterized in that: The laser (1), adjustable beam expander (2), aconical lens (3), focusing mirror (4) and scanning galvanometer (5) are arranged in the same plane.

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