BOPP Film Lithography Label Control Method and System

Abstract

The present invention relates to the technical field of cigarette packaging materials, and discloses a control method and system for BOPP film lithography labels, including monitoring the temperature distribution in the lithography machine, analyzing the temperature distribution to predict the shrinkage amount of the BOPP film in the lithography stage; triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage amount control parameters, so that the shrinkage amount of the BOPP film in the lithography stage is within the target shrinkage amount; wherein, the shrinkage amount control parameters include exposure energy and development time. The method and system of the present invention, by analyzing the temperature distribution in the lithography machine in real time, predicting the shrinkage amount of the BOPP film in the lithography stage, and dynamically adjusting key parameters such as exposure energy and development time, ensure that the shrinkage amount is controlled within the target range, thereby effectively solving the problems of pattern deformation and reduced flatness caused by the shrinkage of the BOPP film.

Description

Technical Field

[0001] The present invention relates to the technical field of cigarette packaging materials, and particularly to a method and system for controlling BOPP film lithographic labels. Background Art

[0002] BOPP (Biaxially oriented polypropylene) film is a biaxially oriented polypropylene film, which has excellent transparency, mechanical strength and barrier properties, and is widely used in the fields of packaging, labeling and anti-counterfeiting, especially for making cigarette packaging materials. With the continuous improvement of the market's requirements for the appearance quality and anti-counterfeiting performance of cigarette packaging, fine printing and hot stamping on BOPP film have become an industry trend. These processes usually involve lithography processes to achieve high-precision pattern transfer and surface treatment.

[0003] However, there is a significant technical problem in the lithography process of BOPP film: due to the high temperature and uneven distribution inside the lithography machine, as well as the thermal shrinkage characteristics of the BOPP film itself, the film material will shrink to varying degrees during the lithography stage. This shrinkage will not only cause pattern deformation and an increase in line width deviation, but also seriously affect the flatness of the product, thereby reducing the appearance quality and functionality of the packaging. Especially in cigarette packaging, the decrease in flatness may affect the sealing and aesthetics of the packaging, and even cause operation failures of the product on high-speed packaging machines.

[0004] Currently, the solutions to the lithography shrinkage problem of BOPP film in the industry mainly focus on material modification (such as reducing the thermal shrinkage rate) and process optimization (such as increasing the baking process and combining with adjusting the baking temperature curve), etc. However, these methods are often difficult to balance production efficiency and quality control, and cannot respond in real time to the impact of temperature fluctuations inside the lithography machine on the shrinkage amount. Summary of the Invention

[0005] Therefore, the present invention aims to overcome the problem of the flatness of lithographic products caused by the shrinkage of BOPP film during the lithography stage in the prior art, and provides a method and system for controlling BOPP film lithographic labels, which can effectively improve the flatness of the product.

[0006] In a first aspect, to solve the above technical problems, the present invention provides a method for controlling BOPP film lithographic labels, including monitoring the temperature distribution inside the lithography machine, analyzing the temperature distribution to predict the shrinkage amount of the BOPP film during the lithography stage; triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage amount control parameters, so that the shrinkage amount of the BOPP film during the lithography stage is within the target shrinkage amount; wherein, the shrinkage amount control parameters include exposure energy and development time.

[0007] In an embodiment of the present invention, performing label lithography according to shrinkage control parameters includes: S10, obtaining the lithography cycle of the BOPP film lithography label, and dividing a plurality of control stages based on the lithography cycle; S20, selecting a first stage and a second stage adjacent thereto, and a second expected shrinkage amount of the second stage; wherein, the first stage is the first control stage in the time sequence of the plurality of control stages; S30, performing label lithography of the first stage on the BOPP film to be lithographed according to the shrinkage control parameters, and obtaining a transverse shrinkage data set and a longitudinal shrinkage data set of the BOPP film in the lithography stage; S40, performing shrinkage amount evaluation within a predetermined window according to the transverse shrinkage data set and the longitudinal shrinkage data set, and obtaining a first shrinkage amount at the end node of the first stage; S50, calculating a deviation between the second expected shrinkage amount and the first shrinkage amount to determine a second shrinkage amount deviation; S60, performing reverse simulation through a simulation tool with the second shrinkage amount deviation and the second stage as constraints to determine the shrinkage control parameters of the second stage; S70, performing label lithography of the second stage according to the shrinkage control parameters of the second stage.

[0008] In an embodiment of the present invention, after performing label lithography of the second stage according to the shrinkage control parameters of the second stage, iterate through S10 to S70 until the first control operation is completed.

[0009] In an embodiment of the present invention, determining the shrinkage control parameters includes obtaining the shrinkage control parameters through reverse simulation by a simulation tool with the lithography cycle and the target shrinkage amount as constraints.

[0010] In an embodiment of the present invention, after the shrinkage amount of the BOPP film in the lithography stage is optimized within the target shrinkage amount, it further includes monitoring the quality parameters of the lithography label, and triggering a second control operation according to the quality parameters; the second control operation includes performing label lithography according to quality control parameters so that the quality of the lithography label is within the target quality; wherein; the quality parameters include the line width and edge roughness of the label pattern.

[0011] In an embodiment of the present invention, the quality control parameters include exposure energy and development time. Obtaining the quality control parameters includes obtaining a line width data set and an edge roughness data set of the lithography label; performing a first quality evaluation within a predetermined window on the line width data set to obtain a first quality index; performing a second quality evaluation within a predetermined window on the edge roughness data set to obtain a second quality index; fusing the first quality index and the second quality index to obtain a fused quality index; operating a PID controller with exposure energy and development time as control parameters and the deviation between the fused quality index and the target quality index being minimized as the goal to obtain the quality control parameters.

[0012] In an embodiment of the present invention, based on a pre-constructed thermal shrinkage model, the temperature distribution is analyzed to predict the shrinkage amount of the BOPP film in the lithography stage; wherein, constructing the thermal shrinkage model includes obtaining a temperature distribution sample set and a BOPP film shrinkage amount sample set from experimental data; using the temperature distribution sample set as input data and the BOPP film shrinkage amount sample set as output data to perform supervised training on a BP neural network until the convergence condition is reached to obtain the thermal shrinkage model.

[0013] In an embodiment of the present invention, a first control operation is triggered according to the prediction result, including inputting the temperature distribution into the thermal shrinkage model to obtain a predicted shrinkage amount value; if the predicted shrinkage amount value is greater than or equal to the target shrinkage amount, the first control operation is triggered.

[0014] In a second aspect, based on the same inventive concept, to solve the above technical problems, the present invention provides a BOPP film lithography label control system, including a temperature monitoring module for real-time monitoring of the temperature distribution inside the lithography machine; a data analysis module for analyzing the temperature distribution to predict the shrinkage amount of the BOPP film in the lithography stage; a first control operation module for triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to shrinkage amount control parameters so that the shrinkage amount of the BOPP film in the lithography stage is within the target shrinkage amount; wherein, the shrinkage amount control parameters include exposure energy and development time.

[0015] In an embodiment of the present invention, it further includes a second control operation module, which is used to trigger a second control operation according to the quality parameters of the lithography label after the shrinkage amount of the BOPP film in the lithography stage is optimized to within the target shrinkage amount; the second control operation includes performing label lithography according to quality control parameters so that the quality of the lithography label is within the target quality.

[0016] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0017] The BOPP film lithography label control method and system of the present invention, by analyzing the temperature distribution inside the lithography machine in real time, predicting the shrinkage amount of the BOPP film in the lithography stage, and dynamically adjusting key parameters such as exposure energy and development time, ensure that the shrinkage amount is controlled within the target range, thereby effectively solving the problems of pattern deformation and flatness decline caused by the shrinkage of the BOPP film. This method can not only improve the accuracy and consistency of lithography labels, but also adapt to temperature fluctuations under different process conditions, providing reliable technical support for the high-quality production of cigarette packaging materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0019] Figure 1 Schematic diagram of the process of controlling a BOPP film photolithography label in a preferred embodiment of the present invention;

[0020] Figure 2 Schematic diagram of a process of performing label lithography according to a shrinkage control parameter in a first control operation of a preferred embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the process of controlling a BOPP film photolithography label according to the second embodiment of the present invention;

[0022] Figure 4 Schematic diagram of the process of obtaining quality control parameters in the second control operation of the second embodiment of the present invention;

[0023] Figure 5 This is a structural block diagram of a BOPP film photolithography label control system in a third embodiment of the present invention;

[0024] Figure 6 This is a structural block diagram of a BOPP film photolithography label control system in a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention. Example

[0026] The BOPP film photolithography label control method and system described in the present invention are applied to the production of BOPP film photolithography for hot-stamped cigarette packaging. The process for producing hot-stamped cigarette packaging consists of a photolithography stage and a hot-stamping stage. The photolithography stage forms a microstructure corresponding to the hot-stamping pattern on the BOPP film surface. For example, ultraviolet light is used to induce a photochemical reaction in the photoresist, thereby forming a concave or convex pattern on the BOPP film. The photolithography stage includes photoresist coating, exposure, and development. A layer of photoresist is evenly coated on the BOPP film surface by spin coating, brush coating, or spray coating. The photoresist-coated BOPP film is placed in a photolithography apparatus and exposed to ultraviolet light (UV) through a mask. During exposure, the mask is marked with a predetermined hot-stamping pattern (such as a trademark or graphic design). Under UV light, the photoresist undergoes a chemical reaction, leaving unexposed areas unchanged and exposed areas soluble. After exposure, a developer is used to remove the unexposed photoresist, leaving the patterned areas of the photoresist film. These patterned areas serve as the "mask" for the subsequent hot-stamping process.

[0027] The temperature during the exposure process of lithography is between 80°C and 120°C. At this temperature, the molecular structure of the BOPP film changes, resulting in film shrinkage or deformation. Especially when the temperature exceeds 100°C, the BOPP film shrinks most significantly. This shrinkage of the BOPP film not only causes pattern deformation and an increase in line width deviation, but also seriously affects the flatness of the product, thereby reducing the appearance quality and functionality of cigarette packaging.

[0028] To address this technical problem, an embodiment of the present invention discloses a control method for BOPP film lithography labels, aiming to solve the problem of the flatness of lithography products caused by the shrinkage of BOPP films during the lithography stage. The technical solutions in this application will be clearly and completely described with reference to the accompanying drawings as follows:

[0029] Referring to Figure 1 As shown, a control method for BOPP film lithography labels includes monitoring the temperature distribution inside the lithography machine, analyzing the temperature distribution to predict the shrinkage amount of the BOPP film during the lithography stage; triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage amount control parameters, so that the shrinkage amount of the BOPP film during the lithography stage is within the target shrinkage amount; wherein, the shrinkage amount control parameters include exposure energy and development time.

[0030] The control method for BOPP film lithography labels of the present invention analyzes the temperature distribution inside the lithography machine in real time, predicts the shrinkage amount of the BOPP film during the lithography stage, and dynamically adjusts key parameters such as exposure energy and development time to ensure that the shrinkage amount is controlled within the target range, thereby effectively solving the problems of pattern deformation and flatness decline caused by the shrinkage of the BOPP film. This method can not only improve the accuracy and consistency of lithography labels, but also adapt to temperature fluctuations under different process conditions, providing reliable technical support for the high-quality production of cigarette packaging materials.

[0031] In a specific application scenario, the temperature distribution inside the lithography machine is monitored. The temperature distribution inside the lithography machine is monitored in real time through temperature sensors or infrared imaging technology. For example, at key positions inside the lithography machine, such as around the exposure light source, different areas of the workbench, and near the heat dissipation system, a plurality of high-precision temperature sensors are evenly arranged. These sensors can sense the temperature changes inside the lithography machine in real time and transmit the data to the control system. The control system collects the data of each temperature sensor at a preset time interval (for example, once per second) to form a temperature distribution matrix. Then, through a special data analysis algorithm, the collected data is processed to analyze information such as temperature differences and temperature change trends in different areas inside the lithography machine, such as interpolation algorithms, statistical analysis algorithms, Fourier transform algorithms, wavelet transform algorithms, or machine learning algorithms. Accurately master the temperature changes during the lithography process to provide data support for subsequent control operations.

[0032] Predict the shrinkage of the BOPP film in the lithography stage based on the analysis results of the temperature distribution, establish a thermal shrinkage model, and predict the shrinkage of the BOPP film in the lithography stage according to the analysis results of the temperature distribution; wherein, constructing the thermal shrinkage model includes obtaining a temperature distribution sample set and a BOPP film shrinkage sample set from experimental data; using the temperature distribution sample set as input data and the BOPP film shrinkage sample set as output data to perform supervised training on the BP neural network until the convergence condition is reached to obtain the thermal shrinkage model.

[0033] The experimental data is obtained from a large number of experiments measuring the shrinkage of the BOPP film at different temperatures. For example, according to the material characteristics and application requirements of the BOPP film, determine the temperature range of the experiment. Generally, the temperature range can be selected from room temperature (25°C) to the highest temperature at which the BOPP film begins to show obvious deformation or damage (such as 150°C), and set multiple test temperature points at a certain temperature interval (such as 5°C or 10°C). Conduct at least 5 repeated experiments at each temperature point, and take the average value as the measurement result of the shrinkage at that temperature. Place the fixture containing the BOPP film sample in a constant temperature oven or heating furnace, and slowly heat it to the set test temperature. The heating rate should be controlled at about 1°C / min to avoid thermal shock to the BOPP film caused by rapid temperature changes; during the heating process, monitor the temperature change in real time through a temperature sensor. When the temperature stabilizes at the set test temperature and remains for 5 minutes, start measuring the shrinkage. This can ensure that the BOPP film fully reaches the thermal equilibrium state and the measurement result is more accurate. Use measuring instruments such as a laser displacement sensor or an electron microscope to measure the dimensional changes of the film in the direction perpendicular to the surface of the BOPP film in the initial state (25°C) and after heating to the set temperature. When measuring, ensure that the measuring beam or the focus of the electron microscope is perpendicular to the surface of the film, and the measuring position is fixed to ensure the consistency of the measurement results. For the measurement with a laser displacement sensor, align the sensor to a specific position on the surface of the BOPP film, record the displacement value at the initial position, and when the temperature stabilizes, record the displacement value at this position again. The difference between the two is the shrinkage of the BOPP film at this temperature. For the measurement with an electron microscope, take surface images of the BOPP film at different temperatures through the electron microscope, use image analysis software to measure the dimensional changes of the film, and calculate the shrinkage.

[0034] The thermal shrinkage model should be understood as constructing a BP neural network architecture according to the structure-thermodynamic model, training the BP neural network architecture through a large amount of experimental data until the convergence condition is met to obtain the thermal shrinkage model. When the verified qualified thermal shrinkage model is applied, inputting the temperature distribution data can obtain the thermal shrinkage of the BOPP film in the lithography stage, and obtaining the shrinkage prediction value under the current temperature distribution based on the thermal shrinkage model.

[0035] After obtaining the shrinkage prediction value, if the shrinkage prediction value is greater than or equal to the target shrinkage, a first control operation is triggered; the first control operation includes performing label lithography according to the shrinkage control parameters, so that the shrinkage of the BOPP film in the lithography stage is within the target shrinkage; wherein, the shrinkage control parameters include exposure energy and development time.

[0036] The target shrinkage is related to the flatness of the final product and the quality of the lithography pattern (such as line width, edge roughness, etc.). The target shrinkage of the BOPP film of the current product is determined in advance according to these related items. If the shrinkage prediction value is within the target shrinkage, the lithography operation continues according to the current process parameters; if the shrinkage prediction value reaches or even exceeds the target shrinkage, it indicates that the influence of the current temperature distribution on the shrinkage of the BOPP film will result in unqualified products, thus triggering the first control operation for intervention control to make the shrinkage of the BOPP film in the lithography stage within the target shrinkage.

[0037] The first control operation includes controlling the exposure energy and development time. The path by which the exposure energy affects the shrinkage of the BOPP film is as follows: when the exposure energy (also known as "ultraviolet light energy") acts on the BOPP film, the molecules in the BOPP film absorb the photon energy, the vibration and rotation of the molecules are intensified, resulting in an increase in the film temperature and causing thermal expansion. After the exposure ends, the film begins to cool and shrink. The greater the exposure energy, the greater the increase in the film temperature and the greater the shrinkage after cooling. When the shrinkage prediction value of the BOPP film exceeds the target shrinkage, the exposure energy is reduced to make up for the shrinkage. After reducing the exposure energy, the shrinkage of the film decreases accordingly. At this time, the development time is adjusted to maintain an appropriate shrinkage: the development time is shortened to prevent insufficient dissolution of the photoresist, which may cause the film surface to be uneven and affect the shrinkage.

[0038] Specifically, such as Figure 2As shown, in one embodiment, performing label lithography according to the shrinkage control parameter includes the following steps: S10. Obtain the lithography cycle of the BOPP film lithography label, and divide multiple control stages based on the lithography cycle; S20. Select the first stage and the second stage adjacent thereto, and the second expected shrinkage of the second stage; wherein, the first stage is the first control stage in the time sequence of the multiple control stages; S30. According to the shrinkage control parameter, perform label lithography of the first stage on the BOPP film to be lithographed, and obtain the lateral shrinkage data set and the longitudinal shrinkage data set of the BOPP film in the lithography stage; S40. Perform shrinkage evaluation within a predetermined window according to the lateral shrinkage data set and the longitudinal shrinkage data set, and obtain the first shrinkage at the end node of the first stage; S50. Calculate the deviation between the second expected shrinkage and the first shrinkage to determine the second shrinkage deviation; S60. With the satisfaction of the second shrinkage deviation and the second stage as constraints, perform reverse simulation through a simulation tool to determine the shrinkage control parameter of the second stage; S70. Perform label lithography of the second stage according to the shrinkage control parameter of the second stage.

[0039] In a specific application scenario, in step S10, obtain the lithography cycle of the BOPP film lithography label, and divide multiple control stages based on the lithography cycle. The lithography cycle is the entire process from the start of exposure to the end of development and the set expected lithography time, which can be set by those skilled in the art according to the actual situation. For example, set the expected lithography time to 2 hours; divide the lithography cycle into multiple control stages according to a predetermined time step, and the predetermined time step is set by oneself according to the actual situation. For example, set the predetermined time step to 5 minutes to obtain multiple control stages; wherein, the multiple control stages have a sequential order in time sequence.

[0040] Next, in S20, select the first stage and the second stage adjacent thereto, and the second expected shrinkage of the second stage; wherein, the first stage is the first control stage in the time sequence of the multiple control stages; the second expected shrinkage is the shrinkage that the BOPP film is expected to reach at the end of the second stage. After the end of the first stage, select the second stage closely adjacent thereto, and the parameters of the second stage must be adjusted based on the shrinkage result of the first stage; the shrinkage target of the second stage is adjusted according to the film shrinkage situation after the end of the first stage lithography. Associating each stage in this way ensures the continuity between different control stages and can adjust the expected target of the next stage according to the actual effect of the previous stage.

[0041] Before performing the first control operation, it is necessary to determine the shrinkage control parameters. Determining the shrinkage control parameters includes obtaining the shrinkage control parameters through reverse simulation using a simulation tool with the constraints of meeting the lithography cycle and the target shrinkage. First, select a simulation tool suitable for the lithography process, such as COMSOL Multiphysics, which can simulate physical properties such as temperature changes, film shrinkage, and stress distribution during the lithography process. Secondly, based on the material properties of the BOPP film, the lithography process principle, etc., establish a lithography process simulation model that can accurately simulate the shrinkage behavior and lithography effect of the BOPP film under different shrinkage control parameters. Then, input the lithography cycle and the target shrinkage into the simulation tool, and automatically adjust the exposure energy and development time. Through iterative simulation, continuously adjust the exposure energy and development time until the shrinkage of the BOPP film in the lithography stage reaches the target shrinkage, and output the exposure energy and development time that meet the lithography cycle and the target shrinkage, which are used as the shrinkage control parameters to provide a basis for the first control operation.

[0042] S30. Further, according to the shrinkage control parameters, perform the label lithography in the first stage on the BOPP film to be lithographed, and obtain the transverse shrinkage data set and the longitudinal shrinkage data set of the BOPP film in the lithography stage. According to the shrinkage control parameters (including exposure energy and development time) determined above, perform the first-stage label lithography on the BOPP film to be lithographed, configure predetermined monitoring nodes, where the time interval between adjacent monitoring nodes is the same and can be set according to requirements, such as monitoring every 30 seconds, and during the lithography process in the first stage, use a laser measurement system. For example, laser sensors can be installed on the transverse and longitudinal directions of the BOPP film, and at the predetermined monitoring nodes, by scanning the surface of the film and recording the length changes before and after shrinkage, the transverse and longitudinal shrinkage amounts can be monitored in real time to obtain the transverse shrinkage data set and the longitudinal shrinkage data set.

[0043] S40. Further, perform shrinkage evaluation within a predetermined window based on the transverse shrinkage data set and the longitudinal shrinkage data set to obtain the first shrinkage amount at the end node of the first stage. Within a predetermined time window (such as the time window of the entire first stage), calculate the average values of the transverse shrinkage data set and the longitudinal shrinkage data set respectively as the shrinkage amounts of the BOPP film in the transverse and longitudinal directions at the end of this stage, that is, the transverse component and the longitudinal component of the first shrinkage amount; according to the preset weight coefficient, perform weighted summation on the transverse shrinkage amount and the longitudinal shrinkage amount to obtain the first shrinkage amount at the end node of the first stage. Through this step, it can be determined whether the shrinkage amount reaches the predetermined target value and whether there are deviations.

[0044] S50. Calculate the deviation between the second expected shrinkage amount and the first shrinkage amount to determine the second shrinkage amount deviation. According to a preset deviation calculation method (such as the Euclidean distance method), calculate the comprehensive deviation between the second expected shrinkage amount and the first shrinkage amount. This deviation value reflects the error generated during the lithography process and provides a basis for adjustment in the subsequent control stage.

[0045] Next, S60. With the second shrinkage amount deviation and the second stage as constraints, perform reverse simulation through a simulation tool to determine the second stage shrinkage amount control parameters. Based on the material properties of the BOPP film, the lithography process principle, and the actual lithography data of the first stage, establish a lithography process simulation model for the second stage. Input the second shrinkage amount deviation and the process requirements of the second stage (such as lithography time, temperature, etc.) as constraint conditions into the simulation model of the second stage. By adjusting the exposure energy and development time in the simulation model, perform multiple reverse simulation calculations to find a set of shrinkage amount control parameters that can meet the second shrinkage amount deviation constraint and optimize the lithography effect as the second stage shrinkage amount control parameters; then perform the label lithography of the second stage according to the second stage shrinkage amount control parameters. It can improve the fineness of shrinkage amount control and achieve the technical goal of quickly and accurately adjusting the exposure energy and development time according to the shrinkage state of the BOPP film.

[0046] Furthermore, after performing the label lithography of the second stage according to the second stage shrinkage amount control parameters, the present application embodiment further includes iteratively looping S10 to S70 until the first control operation is completed.

[0047] In a specific application scenario, after performing the label lithography of the second stage according to the second stage shrinkage amount control parameters, in the same way, iteratively loop S10 to S70 to continue to optimize and adjust the shrinkage amount control parameters of the third stage, the fourth stage, and subsequent stages until the first control operation is completed, so that the shrinkage amount of the BOPP film in the lithography stage is within the target shrinkage amount. By performing iterative feedback control, the quality and performance of the label lithography can be ensured to be stable throughout the first control cycle and finally meet the predetermined design requirements. Embodiment

[0048] The difference between the embodiments of the present invention and Embodiment 1 is only that, after the solution of Embodiment 1 is completed, that is, after the shrinkage of the BOPP film in the lithography stage is optimized within the target shrinkage, further optimization is included. The premise of the optimization is that even though the shrinkage of the BOPP film has been effectively controlled, in the actual production process, changes in exposure energy and development time will still affect the quality of the lithographic label. The magnitude of the exposure energy affects the photosensitivity and curing effect of the photoresist, and thus affects the formation of the label pattern; the length of the development time determines the dissolution and removal degree of the photoresist, and plays an important role in the details and edge quality of the pattern. Changes in these factors will cause deviations in quality parameters such as the line width and edge roughness of the label pattern, making it difficult to stably control the label quality within the target quality.

[0049] To solve the above problems, as shown in Figure 3 An embodiment of the present invention provides a method for controlling a BOPP film lithographic label. After the shrinkage of the BOPP film is stably controlled, it further includes monitoring the quality parameters of the lithographic label and triggering a second control operation according to the quality parameters; the second control operation includes performing label lithography according to quality control parameters so that the quality of the lithographic label is within the target quality; wherein; the quality parameters include the line width and edge roughness of the label pattern.

[0050] On the one hand, by precisely controlling the shrinkage of the BOPP film in the lithography stage and optimizing it within the target shrinkage, the size deviation of the label pattern caused by film shrinkage is avoided. On the other hand, further monitoring the quality parameters of the lithographic label and triggering a second control operation according to the quality parameters can adjust the label lithography process in real time, compensate for the influence brought by changes in exposure energy and development time, thereby effectively improving the stability of the label quality and ensuring that the quality of each label can be maintained within the target quality.

[0051] Further, the quality control parameters include exposure energy and development time. As shown in Figure 3 obtaining the quality control parameters includes obtaining a line width data set and an edge roughness data set of the lithographic label; performing a first quality evaluation within a predetermined window on the line width data set to obtain a first quality index; performing a second quality evaluation within a predetermined window on the edge roughness data set to obtain a second quality index; fusing the first quality index and the second quality index to obtain a fused quality index; running a PID controller with exposure energy and development time as control parameters and aiming at minimizing the deviation between the fused quality index and the target quality index to obtain the quality control parameters.

[0052] In a specific application scenario, a high-resolution scanning electron microscope (SEM) or a laser profiler is used to scan and measure the line width of the label pattern after lithography to obtain line width data; an atomic force microscope (AFM) or an optical interferometer is used to measure the microscopic topography of the label pattern edge to obtain edge roughness data. The line width data set and the edge roughness data set respectively record the measured line widths and roughnesses of the label pattern at different positions, covering the entire label pattern area. A predetermined window range is set, such as a specific area of the entire label area or the central area of the label, for line width evaluation. The first quality index may include the average value, standard deviation, or other indexes for evaluating pattern accuracy of the line width. According to these indexes, it is evaluated whether the line width of the lithographic label meets the target specifications. An analysis window is set, such as a specific area of the pattern edge, to calculate the roughness index of each edge. The second quality index may include the mean value, maximum value, minimum value, etc. of the edge roughness. Using these data, it is determined whether the label pattern edge meets the target requirements and whether there is excessive roughness. The quality evaluation results of the line width and the edge roughness are fused into a comprehensive quality index. For example, the first quality index and the second quality index can be weighted and summed according to a preset weight to obtain a fused quality index; the weight can be adjusted according to the relative importance of the line width and the edge roughness to the label function and appearance. Using the proportional-integral-differential (PID) control algorithm, according to the deviation between the fused quality index and the target quality index, the exposure energy and the development time are adjusted to obtain quality control parameters.

[0053] It should be noted that after the shrinkage amount of the BOPP film is stably controlled and the label quality is outside the target, the second control operation is triggered. The control objects of the first control operation and the second control operation are both the exposure energy and the development time. After the shrinkage amount of the BOPP film is stably controlled, the exposure energy and the development time are adjusted in small steps. That is to say, the adjustment range of the second control operation is smaller than the minimum adjustment range of the first control operation. In this way, the adjustment balance between the label quality and the flatness of the BOPP film is achieved, and finally the flatness, line width and edge roughness of the label all meet the target requirements. Embodiment

[0054] Based on the same inventive concept as in Embodiment 1, an embodiment of the present invention provides a BOPP film lithographic label control system, referring to Figure 5 as shown, which includes a temperature monitoring module for real-time monitoring of the temperature distribution in the lithography machine; a data analysis module for analyzing the influence of the temperature distribution on the shrinkage amount of the BOPP film during the lithography stage; a first control operation module for triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage amount control parameters, so that the shrinkage amount of the BOPP film during the lithography stage is within the target shrinkage amount; wherein, the shrinkage amount control parameters include exposure energy and development time.

[0055] The BOPP film lithography label control system according to the embodiments of the present invention is used to execute the BOPP film lithography label control method in Embodiment 1, and has the same technical effects as those in Embodiment 1, which will not be elaborated here. Embodiment

[0056] The difference between the embodiment of the present invention and Embodiment 3 is only that, on the basis of Embodiment 3, it further includes a second control operation module, and the second control operation module is used to trigger a second control operation according to the quality parameters of the lithography label after the shrinkage amount of the BOPP film in the lithography stage is optimized within the target shrinkage amount; the second control operation includes performing label lithography according to the quality control parameters so that the quality of the lithography label is within the target quality.

[0057] The BOPP film lithography label control system according to the embodiments of the present invention is used to execute the BOPP film lithography label control method in Embodiment 2, and has the same technical effects as those in Embodiment 2, which will not be elaborated here.

[0058] In summary, for the BOPP film lithography label control method and system of the present invention, by analyzing the temperature distribution in the lithography machine in real time, predicting the shrinkage amount of the BOPP film in the lithography stage, and dynamically adjusting key parameters such as exposure energy and development time, the shrinkage amount is ensured to be controlled within the target range, thereby effectively solving the problems of pattern deformation and flatness decline caused by the shrinkage of the BOPP film. This method can not only improve the accuracy and consistency of lithography labels, but also adapt to temperature fluctuations under different process conditions, providing reliable technical support for the high-quality production of cigarette packaging materials.

[0059] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for realizing in the process Figure 1 each process or multiple processes and / or blocksFigure 1 means for the functions specified in one or more blocks.

[0061] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the functions specified in one Figure 1 process or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks.

[0062] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one Figure 1 process or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks.

[0063] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A control method for BOPP film lithographic labels, characterized in that: Including, monitoring the temperature distribution inside the lithography machine, analyzing the shrinkage amount of the BOPP film during the lithography stage based on the temperature distribution for prediction; triggering a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage control parameters so that the shrinkage amount of the BOPP film during the lithography stage is within the target shrinkage amount; wherein, the shrinkage control parameters include exposure energy and development time; Performing label lithography according to the shrinkage control parameters includes, S10. Obtaining the lithography cycle of the BOPP film lithography label, and dividing multiple control stages based on the lithography cycle; S20. Selecting the first stage and the adjacent second stage, as well as the second expected shrinkage amount of the second stage; wherein, the first stage is the first control stage in the time sequence of the multiple control stages; S30. Performing label lithography on the BOPP film to be lithographed in the first stage according to the shrinkage control parameters, and obtaining the lateral shrinkage data set and the longitudinal shrinkage data set of the BOPP film during the lithography stage; S40. Evaluating the shrinkage amount within a predetermined window based on the lateral shrinkage data set and the longitudinal shrinkage data set to obtain the first shrinkage amount at the end node of the first stage; S50. Calculating the deviation between the second expected shrinkage amount and the first shrinkage amount to determine the second shrinkage amount deviation; S60. Taking the satisfaction of the second shrinkage amount deviation and the second stage as constraints, performing reverse simulation through a simulation tool to determine the shrinkage control parameters of the second stage; S70. Performing label lithography on the second stage according to the shrinkage control parameters of the second stage; Analyzing the shrinkage amount of the BOPP film during the lithography stage based on the pre-constructed thermal shrinkage model for prediction; constructing the thermal shrinkage model includes, obtaining a temperature distribution sample set and a BOPP film shrinkage amount sample set from experimental data; supervising and training a BP neural network with the temperature distribution sample set as input data and the BOPP film shrinkage amount sample set as output data until the convergence condition is reached to obtain the thermal shrinkage model.

2. The control method of the BOPP film lithography label according to claim 1, wherein: After performing label lithography on the second stage according to the shrinkage control parameters of the second stage, iteratively loop through S10 to S70 until the first control operation is completed.

3. The BOPP film lithography label control method according to claim 1 or 2, characterized in that: Determining the shrinkage control parameters includes obtaining the shrinkage control parameters through reverse simulation by a simulation tool with the satisfaction of the lithography cycle and the target shrinkage amount as constraints.

4. The BOPP film lithography label control method according to claim 1, characterized in that: After the shrinkage amount of the BOPP film during the lithography stage is optimized to within the target shrinkage amount, it further includes, monitoring the quality parameters of the lithography label, and triggering a second control operation according to the quality parameters; the second control operation includes performing label lithography according to the quality control parameters so that the quality of the lithography label is within the target quality; wherein; the quality parameters include the line width and edge roughness of the label pattern.

5. The control method of the BOPP film lithography label according to claim 4, characterized in that: The quality control parameters include exposure energy and development time, and obtaining the quality control parameters includes, obtaining the line width data set and the edge roughness data set of the lithography label; performing a first quality evaluation within a predetermined window on the line width data set to obtain a first quality index; performing a second quality evaluation within a predetermined window on the edge roughness data set to obtain a second quality index; Fuse the first quality index and the second quality index to obtain a fused quality index; Use the exposure energy and development time as control parameters, and run a PID controller with the goal of minimizing the deviation between the fused quality index and the target quality index to obtain the quality control parameters.

6. The control method of the BOPP film lithography label according to claim 1, characterized in that: Trigger a first control operation according to the prediction result, including Input the temperature distribution into the thermal shrinkage model to obtain a predicted shrinkage value; If the predicted shrinkage value is greater than or equal to the target shrinkage amount, trigger the first control operation.

7. A BOPP film lithography label control system for implementing the BOPP film lithography label control method according to any one of claims 1-6, characterized in that: Including A temperature monitoring module that monitors the temperature distribution inside the lithography machine in real time; A data analysis module that analyzes the temperature distribution to predict the shrinkage amount of the BOPP film during the lithography stage; A first control operation module that triggers a first control operation according to the prediction result; the first control operation includes performing label lithography according to the shrinkage control parameters so that the shrinkage amount of the BOPP film during the lithography stage is within the target shrinkage amount; wherein, the shrinkage control parameters include exposure energy and development time.

8. The BOPP film lithography label control system according to claim 7, characterized in that: It further includes a second control operation module, which is used to trigger a second control operation according to the quality parameters of the lithography label after the shrinkage amount of the BOPP film during the lithography stage is optimized to within the target shrinkage amount; the second control operation includes performing label lithography according to the quality control parameters so that the quality of the lithography label is within the target quality.

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