Laser spot focal plane measurement system and measurement method

Abstract

A laser spot focal plane measurement system and a measurement method are disclosed. The laser spot focal plane measurement method includes the steps of: detecting the thermal radiation energy of a laser spot on the surface of a workpiece, obtaining the optimal focal plane based on the thermal radiation energy of different laser spot focal planes, and establishing a relationship between different laser spot focal planes and thermal radiation energy (S10); and adjusting the distance between the surface of the workpiece and the optimal focal plane of the laser spot in real time during the processing process based on the relationship between different laser spot focal planes and thermal radiation energy (S20). This method is advantageous for achieving micro-level measurement accuracy, improving the measurement accuracy of the focal plane, improving real-time compensation of the laser spot focal plane during the processing process, and improving the machinability of laser processing.

Description

[Technical Field]

[0001] The present invention relates to the field of laser technology, and more particularly to a laser spot focal plane measurement system and a measurement method. [Background technology]

[0002] Laser processing devices work by applying a high-energy-density spot, focused by an optical focusing system, to the workpiece. The relative position of the optimal focal plane of the laser spot to the workpiece determines the magnitude of the laser spot and the power density acting on the workpiece. Therefore, the optimal focal plane of the laser spot plays a crucial role in processing quality. In actual manufacturing, differences in optical focusing systems result in variations in the optimal focal plane of the laser spot. Consequently, quickly, accurately, and reliably obtaining the optimal focal plane of the laser spot in an optical focusing system is one of the important technologies in laser processing.

[0003] Conventional methods for determining the optimal focal plane of a laser spot primarily involve visually observing the size of the processing sparks to determine the optimal focal plane position. However, this method is inaccurate, and visually observing the sparks poses a significant safety risk. [Overview of the project] [Problems that the invention aims to solve]

[0004] The objective of the present invention is to provide a laser spot focal plane measurement system and measurement method that solve the problem of low measurement accuracy and safety hazards associated with the laser focal plane. [Means for solving the problem]

[0005] To solve the above technical problems, the present invention provides A step of detecting the thermal radiation energy of a laser spot on the surface of a workpiece, obtaining the optimal focal plane based on the thermal radiation energy of different laser spot focal planes, and establishing the relationship between different laser spot focal planes and thermal radiation energy; and A laser spot focal plane measurement method is provided, which includes the step of adjusting the distance between the surface of the workpiece and the optimal focal plane of the laser spot in real time during the processing process, based on the relationship between the different laser spot focal planes and thermal radiation energy.

[0006] The step of optionally adjusting the distance between the surface of the workpiece and the optimal focal plane of the laser spot in real time during the processing process, based on the relationship between the different laser spot focal planes and thermal radiation energy, is:

[0007] A step of obtaining the thermal radiation energy of the first focal plane; The first step involves determining whether the thermal radiation energy of the first focal plane is less than the thermal radiation energy of the optimal focal plane. If it is less, proceed to the next step; otherwise, return to the previous step. A step of moving one step in a predetermined direction; A step to obtain the thermal radiation energy of the second focal plane; Determine whether the thermal radiation energy of the second focal plane is greater than the thermal radiation energy of the first focal plane. If the value is large, the optimal focal plane position of the laser spot is calculated based on the relationship between the different laser spot focal planes and the thermal radiation energy, and the deviation position along the original predetermined direction is compensated for. If the difference is not large, the method includes the step of calculating the optimal focal plane position of the laser spot based on the relationship between the different laser spot focal planes and the thermal radiation energy, and compensating for the deviation along the opposite direction from the original predetermined direction.

[0008] The step pitch is optionally 1 μm to 10 μm.

[0009] The step of selectively obtaining the optimal focal plane and establishing the relationship between different laser spot focal planes and thermal radiation energy is: A step of moving the focal plane of the laser spot to the theoretically optimal focal plane and measuring the thermal radiation energy; A step of moving the focal plane of the spot in equal step pitch units to measure the thermal radiation energy; and The process includes the steps of: collecting the thermal radiation energy of each focal plane, processing the data, determining the laser spot focal plane at which the thermal radiation energy is maximum as the optimal focal plane for the laser spot, and establishing a relationship between different laser spot focal planes and thermal radiation energy.

[0010] Optionally, the data processing may include the step of performing polynomial fitting on different laser spot focal planes and thermal radiation energies to obtain corresponding polynomial constants, the fitting equations being as follows: y = ax^5 + bx^4 + cx^3 + dx^2 + ex + f

[0011] Here, y is the thermal radiation energy, x is the focal plane position of different laser spots, and a, b, c, d, e, and f are fitting constants.

[0012] Selectively, moving the focal plane of the laser spot at an equal step pitch allows for direct precision measurement; or, moving the focal plane of the laser spot at an equal step pitch allows for rough measurement first, followed by precision measurement at the position where the rough measurement thermal radiation energy is maximum.

[0013] Optionally, the movement step pitch for the rough measurement is 100 μm to 900 μm, and the movement step pitch for the precision measurement is 1 μm to 10 μm.

[0014] Based on a similar inventive concept, the present invention provides a laser spot focal plane measurement system for performing the laser spot focal plane measurement method described in any one of the above-mentioned items, A laser module that generates a laser beam, irradiates the surface of the workpiece device with the laser beam to generate a laser spot, and also converts it into a thermal radiation beam on the surface of the workpiece device; A detection module that measures the thermal radiation energy of laser spots with different focal planes; and An optimal focal plane is obtained based on the thermal radiation energy of different laser spot focal planes measured by the detection module, a relationship between different laser spot focal planes and thermal radiation energy is established, and based on the relationship between different laser spot focal planes and thermal radiation energy, during the processing process, a control module that adjusts the distance between the surface of the workpiece device and the optimal focal plane of the laser spot in real time; provides a laser spot focal plane measurement system including.

[0015] Optionally, the measurement system is used when performing displacement in the vertical direction to obtain the focal planes of different laser spots.

[0016] Optionally, the workpiece device is used when performing displacement in the vertical direction to obtain the focal planes of different laser spots.

[0017] Optionally, the laser module includes a laser emission unit, a reflection unit, and a beam adjustment unit. The laser emission unit is used to generate a laser beam, the reflection unit is used to change the propagation path of the laser beam, and the beam adjustment unit is used to collimate, diffuse, and shape the laser beam.

[0018] Optionally, the reflection unit is a dichroic mirror.

[0019] Optionally, the dichroic mirror is used for reflection of the laser beam and transmission of the thermal radiation beam.

[0020] The dichroic mirror is optionally used to reflect the laser beam with a wavelength of 800 nm to 850 nm, and the dichroic mirror is optionally used to transmit the thermal radiation beam with a wavelength of 1500 nm to 2500 nm.

[0021] Optionally, the optical paths of the reflection unit, the beam adjustment unit, and the detection module are coaxial.

[0022] Optionally, the detection module includes a thermal radiation sensor, which is used to detect the thermal radiation energy of the laser spot.

[0023] In the laser spot focal plane measurement system and measurement method according to the present invention, by detecting thermal radiation energy, the optimal focal plane is obtained based on the thermal radiation energy of different laser spot focal planes, and by establishing the relationship between different laser spot focal planes and thermal radiation energy, micro-level measurement accuracy is achieved and focal plane measurement accuracy is improved. Furthermore, based on the relationship between different laser spot focal planes and thermal radiation energy, the distance between the surface of the workpiece device and the optimal focal plane of the laser spot is adjusted in real time during the processing process, and the focal plane position of the laser spot is controlled in a closed loop during the processing process, which is advantageous for improving the real-time compensation effect of the focal plane of the laser spot during processing and improving the machinability of laser processing. [Brief explanation of the drawing]

[0024] Those skilled in the art will understand that the accompanying drawings are provided to better understand the present invention and do not limit its scope.

[0025] [Figure 1] This is a schematic diagram of a laser spot focal plane measurement system according to an embodiment of the present invention. [Figure 2] This is a flowchart of a laser spot focal plane measurement method according to an embodiment of the present invention. [Figure 3]This is a flowchart of a method for obtaining the optimal focal plane of a laser spot according to an embodiment of the present invention. [Figure 4] This graph shows the relationship between the laser spot focal plane and thermal radiation energy according to an embodiment of the present invention. [Figure 5] This is a flowchart of a real-time closed-loop control method for the laser spot focal plane according to an embodiment of the present invention. [Modes for carrying out the invention]

[0026] To further clarify the purpose, advantages, and features of the present invention, the invention will be described in more detail below with reference to the drawings and specific embodiments. It should be noted that the drawings are in a highly simplified form, are not drawn proportionally, and are merely for the purpose of easily and clearly illustrating the purpose of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often only parts of the actual structures. In particular, the key points shown in each drawing vary, and different scales may be used.

[0027] In this invention, the singular forms "one," "one," and "the said" include multiple objects; the term "or" is usually used to mean "and / or"; the term "several" is usually used to mean "at least one"; the term "at least two" is usually used to mean "two or more than two"; and the terms "first," "second," and "third" are merely for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features that are limited by “first,” “second,” and “third” may explicitly or implicitly include one or at least two such features, the terms “one end” and “the other end” and “near end” and “far end” usually refer to two corresponding parts, including endpoints, and the terms “attachment,” “connected to one another,” and “connection” should be understood broadly, for example, they may be fixedly connected, detachably connected, or become one; they may be mechanically connected, electrically connected; they may be directly connected, indirectly connected via an intermediate medium, or be internal communication between two elements or an interaction relationship between two elements. Also, as used in the present invention, one element is attached to another element, and there is usually a connection, coupling, mating or transmission relationship between the two elements, and the connection, coupling, mating or transmission between the two elements may be direct or indirectly via an intermediate element, and should not be understood to indicate or imply a spatial positional relationship between the two elements. In other words, unless otherwise explicitly stated in the content, one element may be in any orientation, such as inside, outside, above, below, or to one side of another element. Those skilled in the art will be able to understand the specific meaning of the above terms in this invention depending on the specific situation.

[0028] Figure 1 is a schematic diagram of a laser spot focal plane measurement system according to an embodiment of the present invention. As shown in Figure 1, this embodiment provides a laser spot focal plane measurement system including a laser module 10, a detection module 20, and a control module 50. The laser module 10 is used to generate a laser beam, which is irradiated onto the surface of a workpiece device 30 to generate a laser spot, and after processing the workpiece device 30, generates thermal radiation, which is the temperature energy of the entire wavelength band. The detection module 20 is used to measure the thermal radiation energy of different laser spot focal planes, specifically, because the working distance between the bottom of the laser module 10 and the workpiece device 30 is different, the thermal radiation energy converted after the laser spot irradiates the workpiece device 30 is different. The control module 50 acquires the optimal focal plane based on the thermal radiation energy of different laser spot focal planes measured by the detection module 20, establishes the relationship between the different laser spot focal planes and the thermal radiation energy, and adjusts the distance between the surface of the workpiece device 30 and the optimal focal plane of the laser spot in real time during the processing process based on the relationship between the different laser spot focal planes and the thermal radiation energy.

[0029] As a non-limiting example, the laser module 10 includes a laser emission unit 101, a reflection unit 102, and a beam adjustment unit 103. The laser emission unit 101 is used to generate a laser beam. The wavelength of the laser beam is, for example, 805 nm to 815 nm. The reflection unit 102 is used to change the propagation path of the laser beam and to process the wavelength band of the required thermal radiation beam generated at the workpiece device 30 by the laser spot. The reflection unit 102 is, for example, a dichroic mirror that almost completely transmits light of a certain wavelength and almost completely reflects light of other wavelengths. In this embodiment, the wavelength range of the reflected beam of the dichroic mirror is, for example, 800 nm to 850 nm, and the wavelength range of the transmitted beam of the dichroic mirror is, for example, 1500 nm to 2500 nm. The beam adjustment unit 103 is used to collimate, diffuse, and shape the laser beam to form the laser spot shape required for the laser processing process. In detail, the reflection unit 102 reflects the entire laser beam, then changes the propagation path of the laser beam, and the laser beam is collimated, diffused, and shaped by the beam adjustment unit 103, and then processed by the workpiece device 30 to generate a thermal radiation beam, which then reaches the reflection unit 102 again, and the reflection unit 102 transmits the thermal radiation beam with a wavelength of 1500 nm to 2500 nm and directs it into the detection module 20.

[0030] The laser spot area generates a temperature field due to the action of the laser, and the magnitude of the temperature is determined by the laser power, which can reach several thousand degrees, especially in the case of high-power processing. The detection module 20 is located above the laser module 10 and is used to detect the thermal radiation energy generated by the laser spot on the workpiece device 30 (including, but not limited to, a substrate or silicon wafer), ensuring that the detection unit 203 (thermal radiation sensor) is not damaged under high-power laser measurement.

[0031] In the laser module 10, the optical paths of the reflection unit 102, the beam adjustment unit 103, and the detection module 20 are coaxial. The detection module 20 and the laser module 10 have coaxial optical paths in their structure and do not occupy space between the laser's working distance, that is, they do not occupy space between the laser module 10 and the workpiece device 30.

[0032] As a non-limiting example, the detection module 20 includes a detection shaping unit 201, a filtering unit 202, and a detection unit 203. The detection shaping unit 201 is used to shape the thermal radiation beam. The filtering unit 202 is used to allow the required wavelength band of the thermal radiation beam to pass through and remove the remaining stray light interference, thereby avoiding its influence on the detection of thermal radiation energy by the detection unit 203 and improving the accuracy of the measurement of thermal radiation energy. The detection unit 203 is used to collect the thermal radiation energy of the thermal radiation beam. The detection unit 203 is, for example, a thermal radiation sensor. In this embodiment, the detection unit 203 is, for example, a photodiode.

[0033] The control module 50 is electrically connected to the detection module 20. The control module 50 receives the thermal radiation energy of different laser spot focal planes detected by the detection module 20, processes the data, and performs real-time closed-loop control to ensure that the workpiece device 30 is positioned at the optimal focal plane of the laser spot during the processing of the workpiece device 30. Specifically, the movement of the measuring system or the workpiece device 30 is controlled by controlling the movement of the moving stage using the control module 50.

[0034] In this embodiment, the laser emission unit 101 emits a laser beam, which is reflected by the reflection unit 102 and then incident on the beam adjustment unit 103 with its propagation path altered. The beam adjustment unit 103 collimates, diffuses, and shapes the laser beam to obtain the laser spot shape required for the laser processing process. The laser beam is irradiated onto the workpiece device 30 to perform processing and generate a thermal radiation beam. The thermal radiation beam is incident on the beam adjustment unit 103 and the reflection unit 102. At this time, the reflection unit 102 transmits the thermal radiation beam, which is then incident on the detection and shaping unit 201 to be shaped, and then filtered again by the filtering unit 202 to remove remaining stray light, allowing only the thermal radiation beam in the required wavelength band to pass through. The detection unit 203 detects the thermal radiation energy of the thermal radiation beam and transmits the collected data to the control module 50. After data processing, the control module 50 obtains the optimal focal plane of the laser spot and establishes the relationship between different laser spot focal planes and thermal radiation energy. In the laser processing process, the control module 50 controls the working distance between the bottom of the laser module 10 and the workpiece device 30 so that the workpiece device 30 is positioned on the optimal focal plane of the laser spot. Adjusting the working distance between the bottom of the laser module 10 and the workpiece device 30 includes adjusting the vertical displacement of the measuring system or adjusting the vertical displacement of the workpiece device 30.

[0035] Figure 2 is a flowchart of the method for measuring the laser spot focal plane according to an embodiment of the present invention. As shown in Figure 2, this embodiment is Step S10 involves detecting thermal radiation energy, obtaining the optimal focal plane based on the different magnitudes of the thermal radiation energy at different laser spot focal planes, and establishing the relationship between different laser spot focal planes and thermal radiation energy; The present invention provides a laser spot focal plane measurement method that includes step S20, which adjusts in real time the distance between the surface of the workpiece and the optimal focal plane of the laser spot during the processing process, based on the relationship between the different laser spot focal planes and thermal radiation energy.

[0036] In a preferred method, as shown in Figure 3, the steps of obtaining an optimal focal plane and establishing the relationship between different laser spot focal planes and thermal radiation energy include steps S11 to S14.

[0037] In step S11, process parameters for laser processing are set. These process parameters are, for example, laser power.

[0038] In step S12, the focal plane of the laser spot is moved to the theoretically optimal focal plane, and the thermal radiation energy is measured. Here, the theoretical value of the optimal focal plane of the laser spot is obtained by theoretical calculation, and the workpiece device 30 is positioned on the theoretically optimal focal plane of the laser spot, i.e., on the initial working distance between the laser module 10 and the workpiece device 30.

[0039] In step S13, the focal plane of the laser spot is moved at an equistep pitch to measure the thermal radiation energy.

[0040] In one embodiment, precision measurements are performed directly. The movement step pitch of the precision measurement is, for example, 1 μm to 10 μm. That is, the measurement system is moved directly in micro-level units, and the thermal radiation energy when each measurement system is vertically displaced is precisely measured. Clearly, this method offers high measurement accuracy.

[0041] In another embodiment, a rough measurement is performed first, followed by a precise measurement at the position where the rough measurement thermal radiation energy is maximum. The movement step pitch for the rough measurement is 100 μm to 900 μm. The movement step pitch for the precise measurement is 1 μm to 10 μm. In other words, the measurement system first moves in steps of 100 μm to perform a rough measurement, and then, near the position where the rough measurement thermal radiation energy is maximum, the measurement system moves in steps of micro-level units to perform a precise measurement. This measurement method is highly efficient. In specific implementations, those skilled in the art can select different measurement methods depending on the actual situation.

[0042] Moving the focal plane of the laser spot at equistep pitches actually changes the working distance between the laser module 10 and the workpiece 30 by moving the measuring system or the workpiece 30.

[0043] In step S14, the thermal radiation energy of each focal plane is collected and processed. The focal plane of the laser spot where the thermal radiation energy is maximum is the optimal focal plane of the laser spot, and a relationship between different laser spot focal planes and thermal radiation energy is established.

[0044] Preferably, the data processing includes performing polynomial fitting for different laser spot focal planes and thermal radiation energies to obtain corresponding polynomial constants. y=ax 5 +bx 4 +cx 3 +dx 2 +ex+f

[0045] Here, y is the thermal radiation energy, x is the focal plane position of different laser spots, and a, b, c, d, e, and f are fitting constants.

[0046] By setting and recording mechanical constants for the entire apparatus, the thermal radiation energy and the vertical position of the measurement system or the workpiece device 30 are determined. Subsequently, based on the measured thermal radiation energy values, the control module 50 calculates the vertical position of the measurement system or workpiece device 30 that requires adjustment, and further, the control module 50 provides feedback control to the movement of the moving stage. The moving stage drives the measurement system or moves the workpiece device 30 to position the workpiece device 30 on the work stage 40, and the moving stage is connected to the work stage 40 or the moving stage is connected to the measurement system to complete closed-loop control of the focal plane during the machining process.

[0047] Figure 4 is a graph showing the relationship between the laser spot focal plane and thermal radiation energy according to an embodiment of the present invention. In Figure 4, the horizontal coordinate is the working distance from the bottom of the laser module 10 to the workpiece device 30, and the vertical coordinate is the thermal radiation energy value. From Figure 4, the working distance from the bottom of the laser module 10 to the workpiece device 30 (vertical displacement value of the measurement system or vertical displacement value of the workpiece device 30) corresponding to the point where the thermal radiation energy value is maximum can be found. This is the optimal focal plane of the laser spot. The working distance from the bottom of the laser module 10 to the workpiece device 30 (vertical position of the measurement system or vertical position of the workpiece device 30) of the optimal focal plane after measurement is recorded for the entire apparatus by setting mechanical constants, and the measurement system or workpiece device 30 is moved to this position by a moving stage before processing so that the exposure focal plane and the surface of the workpiece device 30 reach the required confocal point. From Figure 4, for example, rough measurement is started with a step pitch of 200 μm, and when the vicinity of the optimal focal plane of the laser spot is reached, precision measurement is performed with a moving step pitch of, for example, 10 μm. The thermal radiation energy at different laser spot focal planes was polynomial-fitted to obtain a polynomial constant, and the correlation coefficient R² of the fitted polynomial is 0.9976.

[0048] Here, the polynomial fitting formula is as follows, for example. y = 4 * 10 6 x 5 - 3 * 10 7 x 4 + 8 * 10 7 x 3 - 1 * 10 8 x 2 + 7 * 10 7 x - 2 * 10 7

[0049] Here, y is the thermal radiation energy and x is the focal plane position of different laser spots.

[0050] As shown in FIG. 5, based on the relationship between the different laser spot focal planes and the thermal radiation energy, in the processing process, the step of adjusting the distance between the surface of the workpiece device and the optimal focal plane of the laser spot in real time is as follows: Step S21 of obtaining the thermal radiation energy P1 of the first focal plane, which is the initial position of the measurement system or the workpiece device 30; Step S22 of determining whether the thermal radiation energy P1 of the first focal plane is smaller than the thermal radiation energy PZ of the optimal focal plane. If it is smaller, the next step (i.e., step S23) is executed; if it is not smaller, return to the previous step (i.e., step S21); Step S23 of moving one step pitch according to a predetermined direction. Here, the step pitch may be 1 μm to 10 μm. In an actual laser spot processing device, there are two types of layouts for the laser spot focal plane measurement system. The first is to fix the laser spot focal plane measurement system at a certain position and place the workpiece device 30 on a moving stage and move it. The second is to place the workpiece device 30 at a certain fixed position and place the laser spot focal plane measurement system on a moving stage and move it; Step S24 of obtaining the thermal radiation energy P2 of the second focal plane. Here, the second focal plane is the position after the laser spot focal plane measurement system or the workpiece device 30 moves one step pitch; and Step S25 includes determining whether the thermal radiation energy P2 of the second focal plane is greater than the thermal radiation energy P1 of the first focal plane; If the value is large, step S26 is performed to calculate the deviation position between the optimal focal plane position and the second focal plane position of the laser spot based on the relationship between different laser spot focal planes and thermal radiation energy, and to compensate for the deviation position along the original predetermined direction; If the deviation is not large, step S27 is performed to calculate the deviation between the optimal focal plane position and the second focal plane position of the laser spot based on the relationship between different laser spot focal planes and thermal radiation energy, and to compensate for the deviation along the opposite direction of the original predetermined direction.

[0051] Here, the relationship between different laser spot focal planes and thermal radiation energy is, i.e., the relationship between the vertical position of the laser spot focal plane measuring system or the workpiece device 30 and thermal radiation energy, or the relationship between different laser working distances between the laser spot focal plane measuring system and the workpiece device 30 and thermal radiation energy; the deviation position compensation is, i.e., the difference between the position of the laser spot focal plane measuring system and the workpiece device 30 corresponding to the optimal focal plane and the position of the laser spot focal plane measuring system and the workpiece device 30 at the current focal plane. By compensating for the deviation position, the workpiece device 30 is controlled in real time to be positioned on the optimal focal plane of the laser spot.

[0052] In this embodiment, when the control module 50 detects that the current thermal radiation energy value P1 of the focal plane is smaller than the optimal thermal radiation energy value PZ of the focal plane, it first controls the moving stage to define one direction and move it in a small step pitch, the moved step pitch must not affect the machining process. That is, within the feasible range of the machining process, the moving step pitch is made as small as possible to obtain the new thermal radiation energy value P2 of the focal plane again and determine the adjusted direction. If the difference between the two sets of thermal radiation energies is greater than 0 (i.e., P2-P1>0), the optimal focal plane position of the laser spot is calculated based on the relationship between the focal plane and thermal radiation energy of different laser spots (the relationship between thermal radiation energy and the laser working distance), and the deviation position is compensated along the original predetermined direction. Conversely, if the difference in thermal radiation energy between the two preceding and succeeding cycles is less than 0 (i.e., P2-P1<0), the optimal focal plane position of the laser spot is calculated based on the relationship between different laser spot focal planes and thermal radiation energy (the relationship between thermal radiation energy and laser working distance), the deviation along the original predetermined opposite direction is compensated, and the focal plane position compensation is finally completed in real time.

[0053] As described above, in the laser spot focal plane measurement system and measurement method according to the present invention, the laser spot focal plane measurement system ensures that the detection unit is not damaged during high-power laser measurement by setting the optical paths of the detection module and the laser module coaxially, avoiding the laser's working distance space, and detecting the thermal radiation energy generated by the laser spot on the workpiece. Because the thermal radiation generated by different laser spot focal planes differs, micro-level precision measurement of the laser spot focal plane is achieved by moving the laser spot focal plane measurement system or the workpiece vertically at the same micro-level step pitch. The control module handles data processing and position localization, and the maximum value of thermal radiation energy is at the optimal focal plane of the laser spot. It also obtains the localization relationship between the thermal radiation energy value and the laser spot focal plane measurement system or workpiece to control the position of the optimal focal plane of the laser spot. In the laser annealing process, the laser spot focal plane measurement system acquires positional information of the work stage and energy information of the laser spot focal plane measurement system in real time via a control module, based on the measured thermal radiation energy and the orientation relationship between the laser spot focal plane measurement system or the workpiece device. During the processing process, the optimal focal plane of the spot is controlled in a closed loop in real time, improving the processability of laser processing.

[0054] In this specification, each example is described progressively, focusing on the differences between each example and others. Identical or similar parts between examples may be referenced to one another. Furthermore, different parts between examples may be used in combination, and the present invention is not limited thereto.

[0055] Furthermore, while the present invention has been disclosed in preferred embodiments, it should be recognized that these embodiments do not limit the present invention. Those skilled in the art can, without departing from the scope of the technical means of the present invention, utilize the technical content disclosed above to make various possible variations and modifications to the technical means of the present invention, or modify them into equivalent embodiments of equivalent changes. Accordingly, all simple modifications, equivalent changes, and modifications made to the above embodiments based on the technology of the present invention, without departing from the scope of the technical means of the present invention, should all be considered to fall within the scope of protection of the technical means of the present invention. [Explanation of Symbols]

[0056] 10-Laser module, 101-Laser emission unit, 102-Reflection unit, 103-Beam adjustment unit, 20-Detection module, 201-Detection shaping unit, 202-Filtering unit, 203-Detection unit, 30-Workpiece device, 40-Work stage, 50-Control module

Claims

1. A step of detecting the thermal radiation energy of a laser spot on the surface of a workpiece, obtaining the optimal focal plane based on the thermal radiation energy of different laser spot focal planes, and establishing the relationship between different laser spot focal planes and thermal radiation energy; and A laser spot focal plane measurement method, characterized by including the step of adjusting the distance between the surface of a workpiece and the optimal focal plane of the laser spot in real time during the processing process, based on the relationship between the different laser spot focal planes and thermal radiation energy.

2. Based on the relationship between the different laser spot focal planes and thermal radiation energy, the step of adjusting the distance between the surface of the workpiece and the optimal focal plane of the laser spot in real time during the processing process is: A step of obtaining the thermal radiation energy of the first focal plane; The first step involves determining whether the thermal radiation energy of the first focal plane is less than the thermal radiation energy of the optimal focal plane. If it is less, proceed to the next step; otherwise, return to the previous step. A step of moving one step in a predetermined direction; A step of obtaining the thermal radiation energy of the second focal plane; A laser spot focal plane measurement method according to claim 1, comprising the steps of: determining whether the thermal radiation energy of the second focal plane is greater than or equal to the thermal radiation energy of the first focal plane; if greater, calculating the optimal focal plane position of the laser spot based on the relationship between the different laser spot focal planes and the thermal radiation energy, and correcting the deviation position along the original predetermined direction; and if not greater, calculating the optimal focal plane position of the laser spot based on the relationship between the different laser spot focal planes and the thermal radiation energy, and correcting the deviation position along the opposite direction of the original predetermined direction.

3. The laser spot focal plane measurement method according to claim 2, characterized in that the step pitch is 1 μm to 10 μm.

4. The steps to obtain the optimal focal plane and to establish the relationship between different laser spot focal planes and thermal radiation energy are as follows: A step of moving the focal plane of the laser spot to the theoretically optimal focal plane and measuring the thermal radiation energy; A step of moving the focal plane of the spot at an equistep pitch to measure the thermal radiation energy; and The laser spot focal plane measurement method according to claim 1, comprising the steps of: collecting the thermal radiation energy of each focal plane, processing the data, determining the laser spot focal plane at the maximum value of the thermal radiation energy as the optimal focal plane of the laser spot, and establishing a relationship between different laser spot focal planes and thermal radiation energy.

5. The laser spot focal plane measurement method according to claim 4, characterized in that the data processing includes the step of performing polynomial fitting on different laser spot focal planes and thermal radiation energies to obtain corresponding polynomial constants, wherein the fitting formula is as follows: y=ax^5+bx^4+cx^3+dx^2+ex+f Here, y is the thermal radiation energy, x is the focal plane position of different laser spots, and a, b, c, d, e, and f are fitting constants.

6. The laser spot focal plane measurement method according to claim 4, characterized in that the focal plane of the laser spot is moved at an equistep pitch to perform a direct precision measurement, or the focal plane of the laser spot is moved at an equistep pitch to perform a rough measurement first, and then a precision measurement at the position where the rough measurement thermal radiation energy is maximum.

7. The laser spot focal plane measurement method according to claim 6, characterized in that the moving step pitch for the rough measurement is 100 μm to 900 μm, and the moving step pitch for the precision measurement is 1 μm to 10 μm.

8. A laser spot focal plane measurement system used to perform the laser spot focal plane measurement method according to any one of claims 1 to 7, A laser module that generates a laser beam, irradiates the surface of a workpiece with the laser beam to create a laser spot, and converts the laser beam into a thermal radiation beam on the surface of the workpiece; A detection module for measuring the thermal radiation energy of different laser spot focal planes; and A laser spot focal plane measurement system characterized by including a control module that obtains an optimal focal plane by the thermal radiation energy of different laser spot focal planes measured by the detection module, establishes a relationship between different laser spot focal planes and thermal radiation energy, and adjusts the distance between the surface of the workpiece and the optimal focal plane of the laser spot in real time during the processing process based on the relationship between the different laser spot focal planes and thermal radiation energy.

9. The laser spot focal plane measurement system according to claim 8, characterized in that the measurement system is used when performing vertical displacement to acquire different focal planes of the laser spot.

10. The laser spot focal plane measurement system according to claim 8, characterized in that the workpiece device is used when performing vertical displacement to acquire different focal planes of the laser spot.

11. The laser spot focal plane measurement system according to claim 8, wherein the laser module includes a laser emission unit, a reflection unit, and a beam adjustment unit, the laser emission unit being used to generate a laser beam, the reflection unit being used to alter the propagation path of the laser beam, and the beam adjustment unit being used to collimate, diffuse, and shape the laser beam.

12. The laser spot focal plane measurement system according to claim 11, characterized in that the reflective unit is a dichroic mirror.

13. The laser spot focal plane measurement system according to claim 12, characterized in that the dichroic mirror is used for reflecting the laser beam and for transmitting the thermal radiation beam.

14. The laser spot focal plane measurement system according to claim 13, characterized in that the dichroic mirror is used for reflecting the laser beam with a wavelength of 800 nm to 850 nm, and the dichroic mirror is used for transmitting the thermal radiation beam with a wavelength of 1500 nm to 2500 nm.

15. The laser spot focal plane measurement system according to claim 11, characterized in that the optical paths of the reflection unit, the beam adjustment unit, and the detection module are coaxial.

16. The laser spot focal plane measurement system according to claim 8, characterized in that the detection module includes a thermal radiation sensor, and the thermal radiation sensor is used to detect the thermal radiation energy of the laser spot.

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