Adjustment and installation method and adjustment and installation system for laser precision cutting light path

Abstract

The invention provides an adjusting and installing method and system for a laser precision cutting light path, and the method comprises the steps: installing and fixing a light through hole type diaphragm on a beam expander, enabling the laser emitted by a laser to pass through the center of the light through hole type diaphragm on the beam expander, enabling the mechanical center of the beam expander to be aligned with the geometric reference of the light path, and enabling the light through hole type diaphragm to pass through the center of the light through hole type diaphragm on the beam expander; finishing the primary spatial position adjustment of the beam expander; according to return light formed by internal reflection of the beam expander, the beam expander is finely adjusted, so that the return light coincides with the center of an outlet of the laser, and the optical axis of the beam expander is collinear with the optical path reference optical axis; an adjustable diaphragm is installed at an outlet of the beam expander, the aperture of the adjustable diaphragm is adjusted to a preset aperture, and an energy distribution diagram of light spots emitted by the field lens is collected; and secondary spatial position adjustment is carried out on the beam expander, so that the center of the light spot energy distribution diagram is aligned with the center of the adjustable diaphragm. According to the invention, the center of the light spot energy distribution diagram is aligned with the center of the adjustable diaphragm, so that high-precision calibration of the laser precision cutting light path is realized.

Description

Technical Field

[0001] This application relates to the field of laser precision cutting technology, and more specifically, to a method and system for adjusting the optical path of laser precision cutting. Background Technology

[0002] In the field of electronic component manufacturing, laser trimming machines are specialized equipment used for laser cutting of surface-mount resistors. The assembly and adjustment accuracy of the optical path system in a laser trimming machine directly determines the cutting quality, product yield, and temperature drift (TCR) characteristics of automotive-grade thin-film products.

[0003] In related technologies, commonly used laser cutting optical path assembly and adjustment methods mainly rely on manual experience judgment. The evaluation of spot energy distribution is crude and lacks quantitative detection methods. The adjustment is made by observing the spot shape with the naked eye. Qualitative observation is often used, which cannot accurately control the wavefront flatness. This easily leads to burrs on the tangent edge, ceramic cracks at the bottom of the tangent, and low pass rate of resistance temperature drift (TCR) characteristic test.

[0004] Therefore, there is an urgent need for an optical path assembly method that can quantitatively control the beam quality and energy distribution to overcome the shortcomings of existing technologies and meet the precision cutting requirements of chip thin-film resistors. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for adjusting the optical path in laser precision cutting, which can solve at least one of the aforementioned technical problems. The specific solution is as follows: According to a specific embodiment of this application, in a first aspect, this application provides a method for adjusting a laser precision cutting optical path, the method comprising: According to the laser's preset optical path, the various optical components of the laser precision cutting optical path system are built at the preset positions on the optical platform; among them, the laser, the mirror group, the beam expander, the galvanometer, and the field mirror are arranged sequentially along the laser optical path direction; Fixed aperture-type diaphragms are installed at the inlet and outlet of the beam expander, respectively. The beam expander is adjusted so that the laser emitted by the laser passes through the center of the aperture-type diaphragm on the beam expander, so that the mechanical center of the beam expander is aligned with the optical path geometric reference, thus completing the initial spatial position adjustment of the beam expander. Based on the return light formed by the reflection inside the beam expander, the beam expander is finely adjusted so that the return light coincides with the center of the laser exit, and the processing and assembly deviation between the mechanical center and the optical center of the beam expander is corrected so that the optical axis of the beam expander is collinear with the optical path reference optical axis. Remove the fixed aperture diaphragms at the entrance and exit of the beam expander, install an adjustable aperture diaphragm at the exit of the beam expander, adjust the aperture of the adjustable aperture diaphragm to a preset aperture, and use a spot energy distribution detection component to collect the spot energy distribution map after the field lens exits. If the center of the light spot energy distribution map is not aligned with the center of the adjustable aperture, the beam expander is adjusted in a secondary spatial position to align the center of the light spot energy distribution map with the center of the adjustable aperture.

[0006] In some possible embodiments, before acquiring the energy distribution map of the light spot emitted after the field lens using the light spot energy distribution detection component, the method further includes: A shearing interferometer is installed between the beam expander and the galvanometer. The magnification of the beam expander is adjusted to a preset magnification. The height of the shearing interferometer is adjusted so that the laser is incident perpendicularly onto the incident surface of the shearing interferometer. If the interference fringes formed on the incident surface of the shearing interferometer do not meet the preset conditions, the collimation adjustment part of the beam expander is adjusted until the interference fringes meet the preset conditions; wherein, the preset conditions are that the interference fringes are parallel to the standard line of the shearing interferometer and the spacing error is less than a preset error threshold.

[0007] In some possible embodiments, the preset magnification is 8-10 times, and the preset error threshold is 5% of the nominal value of the stripe spacing.

[0008] In some possible embodiments, the optical components of the laser precision cutting optical path system, which are constructed at preset positions on the optical platform, include: The laser is turned on to output a laser beam, which is then incident on the beam expander via a group of reflectors. Remove the beam expander, and set a contour block with a central hole at the preset entrance and preset exit positions of the beam expander. The height of the central hole of the contour block is consistent with the laser beam exit height of the laser. Fine-tune the attitude of the reflector group so that the laser beam passes through the central holes of the two contour blocks to complete the optical path collimation and determine the optical path reference optical axis.

[0009] In some possible embodiments, the mirror assembly includes two 45° mirrors; The fine-tuning of the attitude of the reflector group includes: adjusting the angle of the two 45° reflectors until the laser beam passes through the center hole of the two equal-height blocks in the center.

[0010] In some possible embodiments, adjusting the aperture of the adjustable aperture to a preset aperture includes: adjusting the aperture of the adjustable aperture to 10-12 mm to block the weak energy portion of the light spot edge formed by the laser beam emitted from the beam expander, thereby reducing the energy gradient between the center and the edge of the Gaussian light spot.

[0011] In some possible embodiments, before adjusting the aperture of the adjustable aperture to a preset aperture, the method further includes: adjusting the light-transmitting aperture of the adjustable aperture to its maximum, and after confirming that the adjustable aperture does not block the laser beam, reducing the light-transmitting aperture of the adjustable aperture to the preset aperture.

[0012] In some possible embodiments, the spot energy distribution detection component includes a laser power meter and a spot profile analyzer CCD camera; wherein, the laser power meter is used to detect the power of the focused spot emitted through the field lens, and the spot profile analyzer CCD camera is used to acquire the spot energy distribution map emitted through the field lens, and to perform data processing on the spot energy distribution map to fit a Gaussian distribution curve.

[0013] In some possible embodiments, the secondary spatial position adjustment of the beam expander includes: fine-tuning the spatial position of the beam expander according to the real-time changes in the beam spot energy distribution map until the center of the beam spot energy distribution map is aligned with the center of the adjustable aperture.

[0014] According to a specific embodiment of this application, in a second aspect, this application also provides an assembly system for laser precision cutting optical paths, the system comprising: Laser precision cutting optical path system; Light spot energy distribution detection component, shearing interferometer, contour block; The laser precision cutting optical path system is assembled using the aforementioned laser precision cutting optical path assembly method.

[0015] Compared with the prior art, the above-described solutions of this application have at least the following beneficial effects: Standardizing the process reduces the uncertainty of human adjustments and improves the repeatability and efficiency of system assembly and debugging.

[0016] By adjusting the spatial position twice (initial mechanical reference alignment and secondary fine calibration based on the laser spot), the deviation between the mechanical center and the optical center of the beam expander is effectively reduced, ensuring that the optical axis is highly collinear with the system reference optical axis. By using the adjustment method of aligning the return light with the laser exit center, the processing and assembly errors of the beam expander itself are actively compensated, improving the actual accuracy of the optical components. Combined with the adjustable aperture and laser spot energy distribution detection, the center of the laser spot is aligned with the center of the aperture, thereby improving the focusing performance and energy distribution uniformity of laser cutting. Through the step-by-step assembly, adjustment and detection method, the optical path construction process is standardized, reducing the uncertainty of human adjustment and improving the repeatability and efficiency of system assembly and adjustment, making it suitable for optical path calibration in the field of high-precision laser processing. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 A flowchart illustrating the assembly method for the laser precision cutting optical path provided in this application; Figure 2 The beam expander outlet aperture of the laser precision cutting optical path adjustment method provided in this application has the largest unobstructed spot size. Figure 3 The laser energy distribution diagram of the laser precision cutting optical path adjustment method provided in this application, showing that the laser spot is not centered; Figure 4 Energy distribution diagram of a beam expander with an outlet diameter of 14mm for the laser precision cutting optical path adjustment method provided in this application; Figure 5 Energy distribution diagram of a beam expander with an outlet diameter of 12mm for the laser precision cutting optical path adjustment method provided in this application; Figure 6 A schematic diagram of interference fringes for the assembly method of the laser precision cutting optical path provided in this application; Figure 7 An optical path block diagram of the optical components of the laser precision cutting optical path system provided in this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0020] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0021] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0022] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0023] In the field of electronic component manufacturing, surface mount resistors are widely used in various electronic products due to their small size and high integration. Laser cutting is the core process in the production of surface mount resistors, enabling resistance adjustment and shape processing. A laser trimming machine is a specialized piece of equipment that uses lasers to cut surface mount resistors. A laser trimming machine is a specialized precision device integrating multiple systems, including optical, measurement, software, motion, and mechanical systems. The assembly and adjustment accuracy of the optical path system in the laser trimming machine directly determines the cutting quality, product yield, and temperature coefficient of resistance (TCR) characteristics of automotive-grade thin-film products.

[0024] The current laser cutting optical path assembly and adjustment methods commonly used in the industry have significant shortcomings: First, they are not optimized for the optical characteristics of specific wavelength lasers (such as 532nm green light). Although 532nm lasers have advantages such as high material absorption rate and low heat-affected zone, the existing assembly and adjustment methods do not match their wavefront propagation characteristics, resulting in low beam collimation accuracy and energy loss of nearly 15% during transmission. Second, beam shaping relies on manual experience and judgment, the assessment of spot energy distribution is rough, and there is a lack of quantitative detection methods. Adjustment is made solely by visually observing the spot shape, and qualitative observation is often used, which cannot accurately control the wavefront flatness. This easily leads to burrs on the tangent edge, ceramic cracks at the bottom of the tangent, and low pass rate of resistance temperature drift (TCR) characteristic tests.

[0025] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0026] Figure 1The flowchart illustrates the assembly method for the laser precision cutting optical path provided in this application, as shown below. Figure 1 As shown in this embodiment, the method for adjusting the laser precision cutting optical path includes: S101. According to the laser's preset optical path, build the various optical components of the laser precision cutting optical path system at the preset positions on the optical platform (product stage); among them, the laser, mirror group, beam expander (e.g., magnification of 2-10 times), two-axis galvanometer (e.g., positioning accuracy ±0.001mm) and field lens (e.g., focal length 125mm, adapted to 532nm laser) are arranged sequentially along the laser optical path direction; The laser can be a 532nm wavelength green light source. The laser beam emitted by the laser is reflected by a mirror and then enters a beam expander. After exiting the beam expander, it enters a galvanometer and is then exited by a field mirror. The two galvanometers are mounted perpendicularly and orthogonally, with the beam reflected at the center of the galvanometer lens. This ensures that the laser beam is precisely incident on the center of the galvanometer lens and, after reflection, passes through the center of the field mirror along a pre-defined optical path. This avoids beam deflection due to lens angle deviations, laying the foundation for precise focusing of the beam spot on the stage and accurate control of the cutting path.

[0027] Understandably, setting up the various optical components of the laser precision cutting optical path system at preset positions on the optical platform (product stage) is for collimating and adjusting the laser beam. In other words, through mechanical positioning and optical calibration, the operation of keeping the propagation path (optical axis) of the 532nm laser straight and consistent with the optical path system's reference is crucial. The core of this operation is eliminating beam deflection and tilt, ensuring that the laser is precisely transmitted along the preset path to the center of subsequent optical components (beam expander, galvanometer, field lens). That is, ensuring that the laser beam itself is free from bending and divergence, and that it is precisely aligned with the core working area of ​​each optical component, laying the foundation for subsequent beam shaping and energy control.

[0028] In some embodiments, the optical components of the laser precision cutting optical path system are constructed at preset positions on the optical platform, including: The laser is turned on and outputs a laser beam. The laser beam is incident on the beam expander through a group of reflectors. The output power of the laser is set to 0.1W of the rated power, so that the 532nm laser beam is incident on the beam expander through two 45° reflectors along the initial optical path.

[0029] Remove the beam expander. At the preset inlet and outlet positions of the beam expander, install contour blocks with central holes. The height of the central holes in the contour blocks should match the laser beam outlet height. Fine-tune the orientation of the mirror assembly to allow the laser beam to pass through the central holes of the two contour blocks, thus completing optical path collimation and determining the optical path reference axis. Specifically, observe at both the beam expander inlet and outlet points, and repeatedly adjust the two 45° mirrors to collimate the optical path and determine the optical axis.

[0030] In some embodiments, the mirror assembly includes two 45° mirrors; fine-tuning the orientation of the mirror assembly includes adjusting the angle of the two 45° mirrors until the laser beam passes through the center hole of the two equal-height blocks in the center.

[0031] S102. Install fixed aperture-type diaphragms at the inlet and outlet of the beam expander respectively, adjust the beam expander so that the laser emitted by the laser passes through the center of the aperture-type diaphragm on the beam expander, align the mechanical center of the beam expander with the optical path geometric reference, and complete the initial spatial position adjustment of the beam expander. It is understandable that the mechanical center of the beam expander cannot be located by the human eye. Therefore, a fixed aperture-type diaphragm is installed on top, with the center of the aperture-type diaphragm aligned with the mechanical center of the beam expander. The centers of the beam expander diaphragm and the exit diaphragm are then adjusted. In this way, the mechanical center of the beam expander is completely aligned with the optical path geometric reference formed by the double diaphragms, thus initially determining the spatial position of the beam expander in the optical path and completing the initial spatial position adjustment of the beam expander.

[0032] S103. Based on the return light formed by the reflection inside the beam expander, fine-tune the beam expander so that the return light coincides with the center of the laser exit, correct the processing and assembly deviation between the mechanical center and the optical center of the beam expander, and make the optical axis of the beam expander collinear with the optical path reference optical axis. It is understandable that the essential significance of the returned light is that the propagation path of the returned light, formed by reflection from the lens group inside the beam expander, follows the optical axis of the beam expander (not the mechanical center). However, the beam expander may have processing / assembly errors (mechanical center ≠ optical axis). Therefore, by observing the position of the returned light, the beam expander mount is finely adjusted (translated / rotated) until the returned light is completely aligned with the center of the laser exit. In this way, the optical axis of the beam expander and the reference optical axis of the laser's output light are precisely aligned in reverse, which corrects the deviation between the mechanical center and the optical center, ensuring that the laser can be transmitted along the reference optical axis without deflection after passing through the beam expander.

[0033] S104. Remove the fixed aperture diaphragms at the entrance and exit of the beam expander, install an adjustable aperture at the exit of the beam expander, adjust the aperture of the adjustable aperture to the preset aperture, and use the spot energy distribution detection component to collect the spot energy distribution map after the field lens. Understandably, the adjustable aperture installed at the beam expander outlet serves to filter the beam energy. The beam energy distribution detection component includes a CCD camera, which acquires the beam energy distribution map and fits it into a Gaussian distribution curve, visually presenting the energy distribution pattern. This provides quantitative data support for determining whether the beam is centered and whether the energy is uniform, avoiding subjective errors from manual observation.

[0034] In some embodiments, adjusting the aperture of the adjustable stop to a preset aperture includes: adjusting the aperture of the adjustable stop to 10-12 mm to block the weak energy portion of the spot edge formed by the laser beam emitted from the beam expander, thereby reducing the energy gradient between the center and the edge of the Gaussian spot.

[0035] Understandably, the preset aperture (10-12mm) is designed for the spot characteristics of a 532nm laser. Its purpose is to precisely block the weak and randomly distributed energy at the edge of the spot. These weak energy regions can lead to an excessive energy gradient during cutting (too strong in the center and too weak at the edges), resulting in problems such as burrs on the tangent and cracks in the ceramic substrate. By reducing the aperture to 10-12mm, the focused spot energy is more concentrated, significantly reducing the energy gradient between the center and edges, thus ensuring cutting accuracy and resistivity-to-resistance (TCR) characteristics.

[0036] In some embodiments, before adjusting the aperture of the adjustable stop to a preset aperture, the method further includes: adjusting the aperture of the adjustable stop to its maximum value, and after confirming that the adjustable stop does not block the laser beam, reducing the aperture of the adjustable stop to the preset aperture.

[0037] Understandably, the maximum aperture is initially set to allow the expanded laser beam to pass through the entire aperture, preventing the aperture from prematurely blocking the effective energy area of ​​the beam. This ensures that a complete original energy distribution map of the beam can be acquired to assess the beam quality, confirm the complete transmission of the beam, and provide accurate data for subsequent determination of whether the beam position needs to be adjusted. Then, the aperture is reduced to a preset size of 10-12mm to precisely select the effective energy area. In this way, the accuracy of energy distribution adjustment is guaranteed.

[0038] S105. If the center of the beam spot energy distribution map is not aligned with the center of the adjustable aperture, perform a secondary spatial position adjustment on the beam expander to align the center of the beam spot energy distribution map with the center of the adjustable aperture.

[0039] In some embodiments, the spot energy distribution detection component includes a laser power meter and a spot profile analyzer CCD camera; wherein, the laser power meter is used to detect the power of the focused spot emitted through the field lens, and the spot profile analyzer CCD camera is used to acquire the spot energy distribution map emitted through the field lens, and to perform data processing on the spot energy distribution map to fit a Gaussian distribution curve.

[0040] Among them, the laser spot profile analyzer CCD camera is a dedicated device that integrates a CCD image sensor. It is used to acquire images of the energy distribution of laser spots and to intuitively display the shape, center position and energy distribution status of the spots.

[0041] In some embodiments, the secondary spatial position adjustment of the beam expander includes: fine-tuning the spatial position of the beam expander according to the real-time changes in the beam spot energy distribution map until the center of the beam spot energy distribution map is aligned with the center of the adjustable aperture.

[0042] For example, a beam energy distribution detection component fixed at the product stage includes a laser power meter and a CCD camera. The laser power meter quantitatively confirms whether the energy of the focused beam meets the standard, ensuring that the laser power meets the cutting requirements and avoiding incomplete cutting due to insufficient power or damage to the resistive substrate and excessive resistance deviation due to excessive power. After the laser is reflected by the two-axis galvanometer and focused at the center of the field lens, the beam spot falls on the detection center of the laser power meter and the CCD camera. The laser power meter detects the power of the focused beam spot, and the CCD camera acquires the energy distribution image and fits it to a Gaussian distribution curve. An adjustable aperture is installed at the beam expander outlet. The aperture is first set to its maximum, and the CCD camera image is observed. If the energy region (light purple part) at the edge of the beam spot is complete and the Gaussian fitting curves on the X and Y axes are complete, it is determined that the adjustable aperture does not block the beam. The aperture of the adjustable aperture at the beam expander outlet is reduced to 12mm to block the weak energy part at the edge of the beam spot and reduce the energy gradient between the center and the edge of the Gaussian beam spot. The CCD camera image is observed. If the center of the beam spot image is located in the center of the aperture circle, the energy distribution conditions are met. If the beam is not centered and the energy distribution is not up to standard, adjust the beam expander position by fine-tuning the beam expander mount while observing the changes in CCD imaging until the energy distribution meets the standard.

[0043] like Figures 2 to 5 As shown, a laser power meter detects the power of the focused spot, and a CCD camera of the spot profile analyzer acquires an energy distribution image and fits it to a Gaussian distribution curve. An adjustable aperture is installed at the beam expander outlet, with the aperture initially set to its maximum. After laser emission, the CCD camera image is observed. The energy region at the edge of the spot (light purple area) is intact, and the Gaussian fitting curves on both the X and Y axes are complete, indicating that the adjustable aperture does not obstruct the beam. Figure 2 The beam expander exit aperture is at its maximum unobstructed size (the light spot); reduce the adjustable aperture of the beam expander exit to 12mm to block the weak energy portion at the edge of the light spot and reduce the energy gradient between the center and edge of the Gaussian spot. Observe the CCD camera image; if the center of the light spot image is centered within the aperture circle, the energy distribution condition is met. If the light spot is not centered, the energy distribution is not up to standard (2-2 CCD imaging, light spot not centered). Adjust the position of the light spot by fine-tuning the beam expander mount while observing the changes in the CCD image until the energy distribution meets the standard. Figure 4 As shown, CCD spot imaging, beam expander exit diameter 14mm; Figure 5 As shown, CCD spot imaging: beam expander exit diameter 12mm.

[0044] In some embodiments, before acquiring the spot energy distribution map after the field lens is emitted using a spot energy distribution detection component, the method further includes: Install a shearing interferometer between the beam expander and the galvanometer, adjust the magnification of the beam expander to the preset magnification, and adjust the height of the shearing interferometer so that the laser is incident perpendicularly onto the incident surface of the shearing interferometer. If the interference fringes formed on the incident surface of the shearing interferometer do not meet the preset conditions, the collimation adjustment part of the beam expander is adjusted until the interference fringes meet the preset conditions; wherein, the preset conditions are that the interference fringes are parallel to the standard line of the shearing interferometer and the spacing error is less than the preset error threshold.

[0045] For example, the preset magnification is 8-10 times, and the preset error threshold is 5% of the nominal value of the stripe spacing.

[0046] In this process, a shearing interferometer is installed between the beam expander and the galvanometer. First, the beam expander's magnification is adjusted to a preset magnification of 8-10 times (to meet the shaping requirements of 532nm lasers). Then, the height of the interferometer is adjusted to ensure that the laser is perpendicularly incident on its incident surface. This is a prerequisite for obtaining accurate interference fringes and avoiding detection errors (non-perpendicular incident light will cause fringe distortion and fail to reflect the true beam state). The shearing interferometer splits the incident laser into two coherent beams, forming interference fringes. The fringe shape directly reflects the wavefront state of the beam. For example... Figure 6 As shown, the interference fringe image is observed using a shearing interferometer (in the image, the interference fringes are parallel to the thin black line when they are within acceptable limits): If the fringes are parallel to the standard line of the shearing interferometer and the spacing error is ≤5% (preset condition), it indicates that the beam has no distortion such as astigmatism or spherical aberration, the wavefront is flat, and it can be accurately focused; if the fringes are curved, tilted (not parallel to the standard line), or unevenly spaced (error >5%), it indicates that the beam is distorted, which will lead to divergence of the subsequent focused spot and disordered energy distribution. When the fringes do not meet the preset conditions, the collimation adjustment part of the beam expander (such as the lens group spacing and angle) is adjusted until the fringes meet the standard. In this way, quantitative standards replace manual experience judgment, avoiding subjective errors and ensuring the edge quality and resistance accuracy of subsequent barrier-type resistor cutting.

[0047] For example, a shearing interferometer is fixed in the optical path between the beam expander and the two-axis galvanometer. The magnification of the beam expander is adjusted to 10X, and the height of the interferometer is adjusted so that the laser is incident on the incident surface of the interferometer. If the fringes are parallel and evenly spaced, and the spacing error is ≤5%, the beam wavefront is considered flat and no adjustment is needed. If the fringes are curved, tilted, or unevenly spaced, it indicates the presence of distortions such as astigmatism or spherical aberration. The beam shaping is completed by adjusting the collimation adjustment part of the beam expander until the interference fringes reach the standard of parallel and even spacing.

[0048] In some implementations, an assembly and adjustment verification step is also included, which is used to confirm whether the optical path assembly and adjustment effect meets the precision cutting requirements of automotive-grade thin-film chip resistors.

[0049] Select a 0402 specification (small thin-film resistor) sample with a resistance of 1kΩ. Set the laser power to 0.2W, cutting speed to 150mm / s, and pulse frequency to 50kHz. Start the laser cutting program for a trial cut. After completion, verify the following indicators: Observe the cutting edge under an optical microscope (1000x magnification). Burrs ≤ 5μm are acceptable. Resistance deviation +0.2% (acceptable standard ≤ ±0.5%): Detected with a precision multimeter with an accuracy of 0.01%. Resistance deviation is a core performance indicator of resistor cutting. A small deviation indicates accurate cutting path, stable laser energy, and no over- or under-adjustment of resistance due to optical path deviation. Pass the TCR test (temperature coefficient of resistance test): TCR characteristics directly affect the high-temperature stability of automotive-grade resistors. Passing the test means that the cutting did not cause cracks in the resistor ceramic substrate. This is due to the shallow cutting depth (0.286μm) brought by the 10x beam expander (with a 12mm aperture), which reduces the impact of the laser on the substrate. This is a key verification of the optical path adjustment to meet automotive-grade requirements. If all three indicators meet the standards, it means that all assembly and adjustment steps, such as beam collimation, shaping, and energy distribution, meet the requirements and the assembly and adjustment is completed. If any indicator fails to meet the standards (such as excessive burrs, excessive resistance deviation, or abnormal TCR), the assembly and adjustment steps above must be returned to, and the interference fringe flatness and spot centering must be re-optimized until the trial cut verification is passed.

[0050] Comparative experiments show that, as detected by laser microscope, the 10x beam expander has a shallower tangent depth than the 7x beam expander (also with a 12mm aperture). This is more conducive to reducing the impact of laser peak energy on the ceramic substrate at the bottom of the tangent, reducing the probability of cracks at the bottom of the tangent, and improving the TCR detection pass rate.

[0051] This application also provides apparatus embodiments that follow the above embodiments, for implementing the method steps of the above embodiments. The interpretation of the same names is the same as that of the above embodiments, and they have the same technical effects as those of the above embodiments, so they will not be repeated here.

[0052] Figure 7 This application provides an optical path block diagram of the optical components of a laser precision cutting optical path system. The system includes: Laser precision cutting optical path system (such as) Figure 7 (as shown) Light spot energy distribution detection component, shearing interferometer, and high-density block with central hole; The laser precision cutting optical path system is assembled using the laser precision cutting optical path assembly method described in the above embodiment.

[0053] For example, an assembly system for laser precision cutting optical paths is assembled according to the following specifications: Laser: Model GH-532, output wavelength 532nm, rated power 5W, beam quality M² < 1.3; Beam expander: Model Jenoptik, magnification 2-10x, 10x magnification with an incident aperture of 3mm, transmittance >96%; Two-axis galvanometer: Model GH-532, positioning accuracy ±0.001mm, maximum scanning speed 500mm / s; Field lens: 115mm focal length, compatible with 532nm laser; Shearing interferometer, laser power meter, spot profile analyzer, CCD camera.

[0054] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0055] The units described in the embodiments of this application can be implemented in software or hardware. The names of the units are not, in some cases, limiting the scope of the unit itself.

Claims

1. A method for adjusting the optical path of laser precision cutting, characterized in that, The method includes: According to the laser's preset optical path, the various optical components of the laser precision cutting optical path system are built at the preset positions on the optical platform; among them, the laser, the mirror group, the beam expander, the galvanometer, and the field mirror are arranged sequentially along the laser optical path direction; Fixed aperture-type diaphragms are installed at the inlet and outlet of the beam expander, respectively. The beam expander is adjusted so that the laser emitted by the laser passes through the center of the aperture-type diaphragm on the beam expander, so that the mechanical center of the beam expander is aligned with the optical path geometric reference, thus completing the initial spatial position adjustment of the beam expander. Based on the return light formed by the reflection inside the beam expander, the beam expander is finely adjusted so that the return light coincides with the center of the laser exit, and the processing and assembly deviation between the mechanical center and the optical center of the beam expander is corrected so that the optical axis of the beam expander is collinear with the optical path reference optical axis. Remove the fixed aperture diaphragms at the entrance and exit of the beam expander, install an adjustable aperture diaphragm at the exit of the beam expander, adjust the aperture of the adjustable aperture diaphragm to a preset aperture, and use a spot energy distribution detection component to collect the spot energy distribution map after the field lens exits. If the center of the light spot energy distribution map is not aligned with the center of the adjustable aperture, the beam expander is adjusted in a secondary spatial position to align the center of the light spot energy distribution map with the center of the adjustable aperture.

2. The method according to claim 1, characterized in that, Before acquiring the energy distribution map of the light spot emitted after passing through the field lens using the light spot energy distribution detection component, the following steps are also included: A shearing interferometer is installed between the beam expander and the galvanometer. The magnification of the beam expander is adjusted to a preset magnification. The height of the shearing interferometer is adjusted so that the laser is incident perpendicularly onto the incident surface of the shearing interferometer. If the interference fringes formed on the incident surface of the shearing interferometer do not meet the preset conditions, the collimation adjustment part of the beam expander is adjusted until the interference fringes meet the preset conditions; wherein, the preset conditions are that the interference fringes are parallel to the standard line of the shearing interferometer and the spacing error is less than a preset error threshold.

3. The method according to claim 2, characterized in that, The preset magnification is 8-10 times, and the preset error threshold is 5% of the nominal value of the stripe spacing.

4. The method according to claim 1, characterized in that, The optical components of the laser precision cutting optical path system, which are constructed at preset positions on the optical platform, include: The laser is turned on to output a laser beam, which is then incident on the beam expander via a group of reflectors. Remove the beam expander, and set a contour block with a central hole at the preset entrance and preset exit positions of the beam expander. The height of the central hole of the contour block is consistent with the laser beam exit height of the laser. Fine-tune the attitude of the reflector group so that the laser beam passes through the central holes of the two contour blocks to complete the optical path collimation and determine the optical path reference optical axis.

5. The method according to claim 4, characterized in that, The mirror assembly includes two 45° mirrors; The fine-tuning of the attitude of the reflector group includes: adjusting the angle of the two 45° reflectors until the laser beam passes through the center hole of the two equal-height blocks in the center.

6. The method according to claim 1, characterized in that, Adjusting the aperture of the adjustable aperture to a preset aperture includes: adjusting the aperture of the adjustable aperture to 10-12mm to block the weak energy portion of the light spot edge formed by the laser beam emitted from the beam expander, thereby reducing the energy gradient between the center and edge of the Gaussian light spot.

7. The method according to claim 6, characterized in that, Before adjusting the aperture of the adjustable aperture to the preset aperture, the method further includes: adjusting the light-transmitting aperture of the adjustable aperture to the maximum, and after confirming that the adjustable aperture does not block the laser beam, reducing the light-transmitting aperture of the adjustable aperture to the preset aperture.

8. The method according to claim 1, characterized in that, The light spot energy distribution detection component includes a laser power meter and a light spot profile analyzer CCD camera; wherein, the laser power meter is used to detect the power of the focused light spot emitted through the field lens, and the light spot profile analyzer CCD camera is used to acquire the light spot energy distribution map emitted through the field lens, and to perform data processing on the light spot energy distribution map to fit a Gaussian distribution curve.

9. The method according to claim 1, characterized in that, The secondary spatial position adjustment of the beam expander includes: fine-tuning the spatial position of the beam expander according to the real-time changes in the beam spot energy distribution map until the center of the beam spot energy distribution map is aligned with the center of the adjustable aperture.

10. A system for adjusting the optical path of a laser precision cutting laser, characterized in that, The system includes: Laser precision cutting optical path system; Light spot energy distribution detection component, shearing interferometer, contour block; The laser precision cutting optical path system is assembled using the laser precision cutting optical path assembly method described in any one of claims 1 to 9.

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