Multi-AOM cascade equipment for independent dynamic regulation and control of laser drilling

Abstract

The utility model relates to multi-AOM cascade equipment for independent dynamic regulation and control of laser drilling, which comprises a light source for generating linearly polarized laser; the plurality of acousto-optic modulators are cascaded, the zero-order light of the front-stage acousto-optic modulator enters the rear-stage acousto-optic modulator, the first-order diffraction light of the acousto-optic modulator is input into the independent sub-optical path, and the zero-order light of the last-stage acousto-optic modulator is input into the independent sub-optical path; n + 1 independent sub light paths are obtained by the N acoustic optical modulators, and N is not less than 1; and a plurality of lenses, wherein each lens is arranged in each sub light path. According to the laser multi-axis machining device, the light splitting function is achieved through the cascaded acousto-optic modulators, a plurality of independent machining optical axes are obtained, dynamic and independent adjustment of sub-beam energy of all the axes can be achieved, the beam energy of all the axes generates different proportions, energy differences are achieved, and the machining precision is improved. Therefore, dynamic regulation and control of materials with different thicknesses and different processing depths are met, and the processing speed is increased.

Description

Technical Field

[0001] This utility model relates to the field of laser processing equipment technology, specifically to a multi-AOM cascade device for independent dynamic control of laser drilling. Background Technology

[0002] Currently, CO2 laser drilling is widely used in the PCB industry for efficient and high-speed drilling of PCBs. However, most existing laser drilling equipment on the market is single-axis processing, and there is no laser drilling equipment based on multi-axis parallel processing using a single light source. Furthermore, there is no laser drilling equipment capable of controlling the energy of each axis of the parallel multi-axis process. Utility Model Content

[0003] To improve the working efficiency of laser processing equipment, this utility model provides a multi-AOM cascade device with independent dynamic control of laser drilling.

[0004] The technical solution of this utility model provides a laser multi-axis processing device, including:

[0005] The light source generates linearly polarized laser light;

[0006] Several acousto-optic modulators are cascaded. The zero-order light of the preceding acousto-optic modulator is incident on the following acousto-optic modulator. The first-order diffracted light of the acousto-optic modulator is input into an independent sub-optical path. The zero-order light of the final acousto-optic modulator is input into an independent sub-optical path. N acousto-optic modulators obtain N+1 independent sub-optical paths, where N is not less than 1.

[0007] Several lenses, each lens is placed in each of the aforementioned sub-optical paths.

[0008] Preferably, a cylindrical mirror is also provided in each of the sub-optical paths. The cylindrical mirror is located in the sub-optical path between the three acousto-optic modulators and the lens, and is used to round the laser beam in the sub-optical path.

[0009] Preferably, it includes an optical deflector located between the light source and the first-stage acousto-optic modulator, the optical deflector modulating the optical path into a periodic circular trajectory in the radial plane of the incident optical axis.

[0010] Preferably, the optical deflector includes a first acousto-optic deflector, a second acousto-optic deflector, and a half-wave plate located between them, arranged sequentially along the optical path.

[0011] Preferably, the deflection direction of the first acousto-optic deflector is consistent with the polarization direction of the incident light; the deflection direction of the second acousto-optic deflector is perpendicular to the deflection direction of the first acousto-optic deflector in a plane perpendicular to the incident light axis; the fast axis of the half-wave plate lies between the two deflection directions and forms a 45-degree angle with one of them.

[0012] The laser multi-axis processing device of this invention achieves the function of beam splitting through cascaded acousto-optic modulators, obtaining multiple independent processing optical axes. It can realize the dynamic and independent adjustment of the energy of each axis beam, and the energy of each axis beam produces different proportions to achieve energy differences, thereby meeting the dynamic control of materials with different thicknesses and different processing depths, and improving the processing speed. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the optical path of the laser processing equipment of this utility model;

[0014] Figure 2 This is a schematic diagram of the principle of the acousto-optic modulator 3 of the laser processing equipment of this utility model;

[0015] Figure 3 This is a schematic diagram of the cascaded acousto-optic modulator 3 of the laser processing equipment of this utility model.

[0016] In the picture:

[0017] 1: Light source; 2: Lens; 21: Galvanometer; 22: Field lens; 3: Acousto-optic modulator; 4: Cylindrical mirror; 6: Optical sensor; 7: Beam splitter; 9: Optical deflector; 91: First acousto-optic deflector; 92: Second acousto-optic deflector; 93: Half-wave plate; 94: Beam expander; 95: Aperture. Detailed Implementation

[0018] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. In this specification, the dimensions of the drawings do not represent the actual dimensions. They are only used to illustrate the relative positional and connection relationships between the components. Components with the same name or the same reference numeral represent similar or identical structures and are limited to illustrative purposes.

[0019] Figure 1 This is a schematic diagram of the laser processing equipment of this application. The laser processing equipment includes a light source 1 and several lenses 2. N acousto-optic modulators 3 are cascaded in the optical path of the laser processing equipment to obtain N+1 sub-optical paths. In each sub-optical path, the laser light is processed by the lens 2 and then irradiated onto the surface of the workpiece. In this scheme, the number N of the acousto-optic modulators 3 is at least one.

[0020] like Figure 2As shown, taking one acousto-optic modulator 3 as an example, the diffraction effect of the acousto-optic modulator can be adjusted by controlling different RF signals applied to it, thereby adjusting the different diffraction ratios of the laser emitted from the acousto-optic modulator 3. For a specific incident light of the acousto-optic modulator 3, its diffraction effect produces first-order and higher-order diffracted light, among which the higher-order diffracted light can be ignored. Therefore, the emitted light of the acousto-optic modulator 3 is mainly zero-order light and first-order diffracted light. The energy ratio of zero-order light to first-order diffracted light can be adjusted by controlling the frequency of the RF signal. Assuming the initial light energy is I0 and the diffraction efficiency of the AOM is η, then the energy of the first-order diffracted light is I1 = η * I0, and the energy of the zero-order light is I0 - I1 = I0 - η * I0 = (1 - η) * I0; the energies of the zero-order and first-order diffracted light of multiple AOMs are deduced in the same way, such as... Figure 3 As shown.

[0021] Figure 1 The diagram shows a laser processing device with three acousto-optic modulators 3. Figure 3 The diagram illustrates the principle of beam splitting. The zero-order light emitted from the acousto-optic modulator 3 continues to enter the next-stage acousto-optic modulator 2, and its first-order diffracted light serves as the light source for the split sub-optical path, which is then transmitted to the lens 2 of that sub-optical path and, after processing by the lens 2, illuminates the surface to be processed. For the final-stage acousto-optic modulator 3, its emitted zero-order light exists as an independent sub-optical path.

[0022] The first-order diffracted light obtained by the acousto-optic modulator 3 has poor focusing due to the diffraction distribution and is stretched in the diffraction direction, resulting in an elongated elliptical spot. To ensure the accuracy and surface quality of subsequent laser processing, a cylindrical mirror 4 is preferably placed between the acousto-optic modulator 3 and the lens 2 in each sub-optical path corresponding to the first-order diffracted light. This mirror circularizes the first-order diffracted light obtained by the acousto-optic modulator 3. The circularized beam enters the lens 2. The lens 2 is used for end-effector adjustment of the emitted laser and typically includes a galvanometer 21 and a field mirror 22. The laser beam is projected onto the processing area of ​​the workpiece after high-speed deflection by the galvanometer and focusing by the field mirror, allowing adjustment of the diameter and taper of the processing hole. In actual equipment, the sub-optical paths can be constructed using a combination of optical fibers or mirrors. The sub-optical paths can be projected onto different processing areas or even independent processing tables, enabling parallel and independent control of laser processing.

[0023] The table below shows the relationship between the energy distribution of diffracted light and the diffraction efficiency of the acousto-optic modulator.

[0024]

[0025] If the goal is to achieve different energy distributions of sub-beams (Z1, Z2, Z3, Z4 axes) from 0 to I0, the diffraction efficiency values ​​of the three acousto-optic modulators 3 can be adjusted. Taking the first two as examples: (1) When the Z1-Z4 axes are not processed (i.e., light emission stops), then the diffraction efficiency of the three AOMs only needs to be 0, and no laser light is emitted; (2) If the Z1-Z4 axes are required to be processed, and the energy requirements of the four axes are the same, then the corresponding Z1 axis energy I1=η1*I0=1 / 4*I0; Z2 axis energy I2=η2*(1-η1)*I0=1 / 4*I0; Z3 axis energy I3=η3*(1-η2)*(1-η1)*I0=1 / 4*I0; Z4 axis energy I4=η4*(1-η3)*(1-η2)*(1-η1)*I0=1 / 4*I0. The rest can be deduced in the same way. These multiple AOM results not only enable precise control of energy on each axis, but more importantly, they allow for energy matching based on different material thicknesses during processing, thereby improving processing speed and capability.

[0026] Before the cascaded acousto-optic modulator 3, an optical deflector 9 is included to achieve the circular rotation of the laser beam path, making the lens 2 particularly suitable for drilling operations. The principle is to make the light path periodically deflect radially along the incident optical axis to form a circle. The optical deflector 9 includes a first acousto-optic deflector 91 and a second acousto-optic deflector 92 arranged sequentially along the light path, with their deflection directions perpendicular to each other in a plane perpendicular to the incident optical axis. It also includes a half-wave plate 93 located between the two. Generally, the deflection direction of the first acousto-optic deflector 91 is consistent with the polarization direction of the incident light, and the fast axis of the half-wave plate 93 lies between the two deflection directions, forming a 45-degree angle with one of them. The function of the half-wave plate 93 is to rotate the polarization direction of the linearly polarized light by 90 degrees so that it coincides with the deflection direction of the second acousto-optic deflector 92. An aperture 95 can be placed after the second acousto-optic deflector 92 to obtain first-order diffracted light while filtering out zero-order and other higher-order diffracted light. An aperture 94 can also be further set to adjust the beam diameter of the laser beam whose optical axis, modulated by the first and second acousto-optic deflectors 91 and 92, is moving in a circular motion. A beam splitter 7 is also provided in the optical path between the laser 1 and the optical deflector 9, which splits the laser light from the source 1 into two beams, one strong and one weak. The strong laser is used for drilling and enters the optical deflector 9, while the weak laser is used for monitoring and enters the corresponding optical sensor 6. The control system monitors the laser intensity of the laser 1 by detecting the signal collected by the optical sensor 6.

[0027] The laser has a wavelength of 9.4 μm, a typical power of 283 W, and a single-pulse frequency of 200 kHz. The linearly polarized light pulse emitted from the laser is split into two beams by a beam splitter (99% reflection, 1% transmission): one beam passes through an attenuator and enters a photodetector for laser monitoring; the other beam is shaped into a flat-top beam by diffractive optical elements, and then passes through a laser beam reducer and aperture for beam optimization and stray light filtering. The adjusted and optimized laser beam passes through three acousto-optic modulators. Due to the diffraction effect of the acousto-optic modulators, 0th and 1st order diffracted light is generated. By applying different RF signals, the energy ratio of the diffracted light is adjusted, thereby achieving dynamic control of the Z1, Z2, Z3, and Z4 axis sub-beams. The four-axis beams are projected onto four (or two different platforms) different processing areas for parallel or independent rapid and efficient material processing. Because the peak power of the laser in this invention is sufficiently high, the energy waste of cascaded AOMs is minimal, and the power of each axis after beam splitting is sufficient to damage the material surface.

[0028] The laser processing equipment of this application can realize dynamic and independent adjustment of the energy of each axis beam, and the energy of each axis beam produces different proportions to achieve energy difference, thereby meeting the dynamic control of materials of different thicknesses and different processing depths, and improving the processing speed; it realizes independent and parallel processing of four axes, improves processing efficiency, and enhances the high-level processing capability of CO2 laser drilling machine.

[0029] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model. Any modifications and improvements made to the technical solution of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A multi-AOM cascade device for independent dynamic control of laser drilling, characterized in that, include: Light source (1) generates linearly polarized laser light; Several acousto-optic modulators (3) are cascaded. The zero-order light of the front-stage acousto-optic modulator (3) is incident on the rear-stage acousto-optic modulator (3). The first-order diffracted light of the acousto-optic modulator (3) is input into an independent sub-optical path. The zero-order light of the final-stage acousto-optic modulator (3) is input into an independent sub-optical path. N acousto-optic modulators (3) obtain N+1 independent sub-optical paths, where N is not less than 1. Several lenses (2), each lens (2) is placed in each of the aforementioned sub-optical paths.

2. The multi-AOM cascaded device for independent dynamic control of laser drilling as described in claim 1, characterized in that, A cylindrical mirror (4) is also provided in each of the sub-optical paths. The cylindrical mirror (4) is located in the sub-optical path between the acousto-optic modulator (3) and the lens (2) and is used to round the laser beam in the sub-optical path.

3. The multi-AOM cascaded device for independent dynamic control of laser drilling as described in claim 1, characterized in that, It also includes an optical deflector (9), which is located between the light source (1) and the first-stage acousto-optic modulator (3). The optical deflector (9) modulates the optical path into a periodic circular trajectory in the radial plane of the incident optical axis.

4. The multi-AOM cascaded device for independent dynamic control of laser drilling as described in claim 3, characterized in that, The optical deflector (9) includes a first acousto-optic deflector (91), a second acousto-optic deflector (92) arranged sequentially along the optical path, and a half-wave plate (93) located between the two.

5. The multi-AOM cascaded device for independent dynamic control of laser drilling as described in claim 4, characterized in that, The deflection direction of the first acousto-optic deflector (91) is consistent with the polarization direction of the incident light; the deflection direction of the second acousto-optic deflector (92) is perpendicular to the deflection direction of the first acousto-optic deflector (91) in a plane perpendicular to the incident light axis; the fast axis of the half-wave plate (93) is between the two deflection directions and is at a 45-degree angle to one of them.

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