A laser transmission welding method and device for flexible circuit packaging

Abstract

The present invention relates to the field of laser transmission welding technology, and more particularly to a laser transmission welding method and apparatus for flexible circuit packaging. The method comprises: providing a plurality of mounting holes on a substrate; attaching a number of absorbent sheets, equal in number to the number of mounting holes, to the component to be welded, the absorbent sheets comprising a light-absorbing layer and a heat-conducting layer; aligning the absorbent sheets with the mounting holes; sequentially irradiating the light-absorbing layers with a laser, causing the light-absorbing layers to absorb laser energy and generate heat. The light-absorbing layers cooperate with the mounting holes to achieve partial welding of the component to be welded and the substrate; and monitoring the temperature of the welding area during welding to determine whether the temperature of the component to be welded and the substrate is less than a set temperature threshold. If the temperature is greater than or equal to the temperature threshold, the laser power is automatically adjusted. The present invention ensures precise control of the welding temperature and stable welding quality.

Description

Technical Field

[0001] The present invention relates to the technical field of laser transmission welding, and in particular to a laser transmission welding method and device for flexible circuit packaging. Background Art

[0002] Flexible circuits have been widely used in electronic skin, wearable devices, flexible displays and other fields due to their lightness, softness and bendability. The manufacture of flexible electronic devices requires the close integration of micro sensors, high-density circuits and flexible substrates to achieve complex functions. The sensitivity of these sensors to temperature, mechanical pressure and changes in the external environment determines that they have special requirements in the packaging process. However, the packaging process of flexible circuits is a key link that affects their performance and reliability. It is necessary not only to ensure a stable connection between the sensor and the substrate, but also to meet the durability requirements for long-term use. Traditional packaging technology mainly relies on gluing and hot pressing processes, but these methods have exposed many problems in practical applications, especially in preventing thermal damage, and it is difficult to meet the high-precision, high-reliability and high-efficiency production requirements of modern flexible electronic devices.

[0003] Furthermore, as flexible electronic devices become increasingly miniaturized and complex, the requirements for packaging processes are becoming increasingly stringent, including higher positioning accuracy, stronger mechanical strength, and shorter processing times. Traditional processes have significant shortcomings in these areas. Therefore, developing a high-precision, high-efficiency packaging process, especially a fast fixation technology for microsensors, has become an urgent issue to be addressed.

[0004] The disadvantages of traditional technology are as follows:

[0005] 1. Thermosensitive materials are susceptible to damage: High temperature and hot pressing can easily cause thermal damage or deformation of thin film flexible substrates and micro sensors, seriously affecting the performance and long-term stability of the sensors.

[0006] 2. Insufficient packaging precision: The gluing process is prone to poor alignment or insufficient bonding strength, which affects the packaging effect.

[0007] 3. Low production efficiency: The traditional process steps are complicated and time-consuming, making it difficult to meet the needs of large-scale production.

[0008] Laser transmission welding is a high-precision, non-contact processing method that exploits the differences in optical transmittance and absorption of materials, enabling fast and efficient welding and making it suitable for flexible electronic packaging. However, existing technologies have yet to provide an optimized laser transmission welding method for securing and sealing microsensors in flexible circuits. Summary of the Invention

[0009] To address the above technical issues, the present invention provides a laser transmission welding method and apparatus for flexible circuit packaging, which achieves precise heating of the welding area and avoids excessive heat effects on sensor sensitive components. Simultaneously, in combination with an optical monitoring and feedback system, the laser power and irradiation time are dynamically adjusted to ensure that the temperature during the welding process remains within a safe range, further preventing high temperatures from damaging sensitive components. The laser transmission welding method comprises the following steps:

[0010] S1: a plurality of mounting holes are provided on the substrate, and an absorption sheet having the same number as the mounting holes is attached to the component to be welded, wherein the absorption sheet includes a light absorbing layer and a heat conducting layer;

[0011] S2: aligning the absorption sheet with the mounting hole, irradiating the light-absorbing layer with a laser in sequence, causing the light-absorbing layer to absorb laser energy and generate heat, and achieving partial welding of the component to be welded and the substrate under the cooperation of the light-absorbing layer and the mounting hole;

[0012] During the welding process, the temperature of the welding area is monitored, and it is determined whether the temperature of the component to be welded and the substrate is less than a set temperature threshold during the welding process. If the temperature is greater than or equal to the temperature threshold, the laser power is automatically adjusted.

[0013] In one embodiment of the present invention, in S2, the method of aligning the absorbent sheet with the mounting hole includes:

[0014] S21: collecting a welding area image and extracting its multimodal features, wherein the multimodal features include edge features, corner features, and texture features;

[0015] S22: monitoring the temperature distribution data and deformation data of the welding area in real time, and inputting the temperature distribution data and the deformation data into a deformation model constructed in advance to obtain a predicted deformation variable;

[0016] S23: dynamically adjusting the weights of different types of features in the multimodal features according to the predicted deformation amount to obtain optimized feature points;

[0017] S24: registering the optimized feature points, eliminating mismatched points, and obtaining a preprocessed set of matching point pairs;

[0018] S25: Based on the set of matching point pairs, a geometric mapping relationship between the image of the component to be welded and the image of the substrate is calculated to obtain a transformation matrix;

[0019] S26: adjusting the position of the absorption sheet of the component to be welded to align with the position of the mounting hole of the substrate in real time according to the transformation matrix.

[0020] In one embodiment of the present invention, in S24, the method for obtaining the preprocessed matching point pair set includes:

[0021] Based on the optimized feature points, the feature points are divided into multiple sub-areas, the number of feature points in each sub-area is counted, and the distribution density in each sub-area is calculated;

[0022] Performing preliminary matching on the optimized feature points to obtain a set of matching point pairs, and calculating a matching score for each matching point pair based on the descriptor similarity of the feature points; and performing geometric transformation fitting on each matching point pair to calculate the fitting error;

[0023] Calculating a matching confidence according to the matching score and the fitting error, dynamically adjusting a threshold of a RANSAC algorithm according to the distribution density and the matching confidence, eliminating mismatched points using the adjusted threshold, and obtaining a preprocessed matching point pair set;

[0024] Each matching point pair includes a feature point in the image of the component to be welded and a feature point in the image of the substrate.

[0025] In one embodiment of the present invention, in S25, the method for obtaining the transformation matrix is as follows:

[0026] For a feature point whose local deformation amount is less than a deformation threshold, an affine transformation matrix is used to adjust the position of the absorber to align with the mounting hole;

[0027] For feature points whose local deformation amount is greater than or equal to the deformation threshold, the transmission transformation matrix is used to adjust the position of the absorption sheet to align with the mounting hole.

[0028] In one embodiment of the present invention, the method for obtaining the affine transformation matrix is as follows:

[0029] Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i :

[0030]

[0031] Use the following formula to solve the affine transformation matrix A:

[0032] A=QP T (PP T )-1 .

[0033] In one embodiment of the present invention, the method for obtaining the transmission transformation matrix is as follows:

[0034] Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i :

[0035]

[0036] The transmission transformation matrix H is solved using the following formula:

[0037] H=argmin H ||Q-PH|| 2 .

[0038] In one embodiment of the present invention, in S22, the method for constructing the deformation model is:

[0039] Obtain the temperature change data ΔT and local deformation Δx of the welding area. Based on ΔT and Δx, a thermal-mechanical coupling deformation prediction model is established:

[0040]

[0041] Among them, α, β, and γ are thermal expansion coefficient, stress sensitivity factor, and transient deformation coefficient, respectively. ext is external stress.

[0042] In one embodiment of the present invention, in S23, the formula for dynamically adjusting the weights of different features in the multimodal features is as follows:

[0043]

[0044] Among them, w i is the weight of the i-th feature, ΔD i is the deformation variable of the i-th feature region, and α is the adjustment coefficient.

[0045] In one embodiment of the present invention, in S23, the method of dynamically adjusting the weights of different types of features in the multimodal features based on the predicted deformation amount also includes: for areas where the degree of deformation exceeds a preset deformation threshold, increasing the weight of texture features; for areas where the degree of deformation does not exceed the preset deformation threshold, increasing the weights of edge features and corner features.

[0046] Based on the same inventive concept, the present invention also provides a laser transmission welding device for flexible circuit packaging, the device comprising:

[0047] A base, wherein the base is provided with a plurality of mounting holes;

[0048] Absorbent sheets having the same number as the mounting holes, each comprising a light-absorbing layer and a heat-conducting layer, the heat-conducting layer being attached to the component to be welded, and having a size smaller than the mounting holes;

[0049] and a control unit, which executes the steps of the laser transmission welding method for flexible circuit packaging, aligns the absorber sheet with the mounting hole, sequentially irradiates the light-absorbing layer with a laser, causes the light-absorbing layer to absorb laser energy and generate heat, and achieves partial welding of the component to be welded and the substrate under the cooperation of the light-absorbing layer and the mounting hole.

[0050] In one embodiment of the present invention, the laser transmission welding device further includes an infrared thermal imager and a laser displacement sensor, wherein the infrared thermal imager and the laser displacement sensor are respectively installed at designated positions close to the welding area and are both connected to the control unit.

[0051] In one embodiment of the present invention, the laser transmission welding device further comprises a camera device, wherein a laser displacement sensor of the camera device is installed at a designated position close to the welding area and is connected to the control unit.

[0052] The present invention also provides a computer storage medium storing a computer software product. The computer software product includes several instructions for enabling a computer device to execute the laser transmission welding method for flexible circuit packaging.

[0053] The above technical solution of the present invention has the following advantages over the prior art:

[0054] This invention achieves precise heating of the weld area through localized laser heating technology, combined with a light-absorbing medium and a thermally conductive material. The light-absorbing medium efficiently absorbs laser energy and converts it into heat, while the thermally conductive material evenly disperses the heat, preventing excessive heat from affecting sensor components. Furthermore, the invention integrates an optical monitoring and feedback system to monitor temperature changes in the weld area in real time. Using a PID control algorithm, the laser power and irradiation time are dynamically adjusted to ensure that the temperature during welding remains within a safe range, further preventing damage to sensitive components caused by high temperatures. This process, through a real-time feedback mechanism, ensures precise control of the welding temperature and stable welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] 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:

[0056] Figure 1 1 is a schematic flow chart of a laser transmission welding method for flexible circuit packaging provided in an embodiment of the present invention;

[0057] Figure 2 is a flow chart of a method for aligning the absorbent sheet with the mounting hole provided in an embodiment of the present invention;

[0058] Figure 3 1 is a partial structural diagram of a laser transmission welding device for flexible circuit packaging provided in an embodiment of the present invention;

[0059] Figure 4 1 is a partial structural diagram of a laser transmission welding device for flexible circuit packaging provided in an embodiment of the present invention;

[0060] Explanation of the reference numerals in the specification: 1. Base; 11. Mounting hole; 2. Absorbent sheet; 3. Welding gun; 4. Control unit; 5. Infrared thermal imager; 6. Laser displacement sensor; 7. Camera device; 8. Component to be welded. DETAILED DESCRIPTION

[0061] 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.

[0062] Example 1:

[0063] like Figure 1 As shown, the present invention provides a laser transmission welding method comprising the following steps:

[0064] S1: A plurality of mounting holes are provided on a substrate made of a transparent flexible polymer (such as PET or PDMS), and an absorber sheet having the same number as the mounting holes is attached to a component to be welded (such as a microsensor), wherein the absorber sheet includes a light absorbing layer and a heat conducting layer;

[0065] S2: aligning the absorption sheet with the mounting hole, and sequentially irradiating the light-absorbing layer with a laser in a multi-point or line welding manner, so that the light-absorbing layer absorbs laser energy and generates heat, and partially welding the component to be welded and the substrate is achieved under the cooperation of the light-absorbing layer and the mounting hole;

[0066] During the welding process, the temperature of the welding area is monitored, and it is determined whether the temperature of the component to be welded and the substrate is less than a set temperature threshold during the welding process. If the temperature is greater than or equal to the temperature threshold, the laser power is automatically adjusted.

[0067] Specifically, during the welding process, the welding parameters are controlled in real time through the optical monitoring and feedback system to prevent the sensor sensitive components from being damaged by high temperature. The infrared thermal imaging system continuously monitors the temperature dynamics of the welding area to ensure that the temperature is maintained within the preset safety threshold. Specifically, the infrared thermal imaging camera captures the thermal map of the welding area, where each pixel corresponds to the temperature value at that location. The system analyzes these temperature data in real time, and once a hot spot area is detected where the temperature exceeds the safety threshold, the automatic adjustment mechanism of the laser power is immediately triggered. Based on the real-time thermal map data, the laser control system uses the PID control strategy to dynamically adjust the laser power by adjusting the proportional (P), integral (I) and differential (D) parameters to adapt to temperature deviations:

[0068] Proportional (P) control: adjusts the laser power based on the deviation between the current temperature and the target temperature. The greater the deviation, the greater the power adjustment.

[0069] Integral (I) control: Accumulates small temperature deviations over a long period of time to prevent the temperature from continuously deviating from the target value.

[0070] Differential (D) control: Predicts temperature change trends and adjusts laser power in advance to avoid excessive temperature fluctuations.

[0071] With PID control, the system can precisely regulate laser power, effectively preventing high temperatures from damaging sensor components. Given the low thermal conductivity and high thermal expansion coefficient of flexible materials, the PID control algorithm has been deeply optimized. Specific optimization measures include:

[0072] Dynamic proportional parameter adjustment mechanism: The proportional gain is adjusted in real time based on the temperature change rate. When the temperature change rate is high, the proportional gain is increased to achieve a fast response; when the temperature approaches the target value, the proportional gain is reduced to avoid overshoot.

[0073] Integral limiting mechanism: Based on the thermal expansion characteristics of flexible materials, the size of the integral term is limited to prevent temperature fluctuations caused by excessive integral terms.

[0074] Differential item prediction function: Combined with the differential item prediction function, infrared thermal imaging data is used to compensate for hot spots in advance to avoid damage to sensitive components due to excessive temperature gradients.

[0075] A dynamic adjustment mechanism ensures that sensitive components are not damaged by overheating. Continuous feedback and correction throughout the welding process ensure that the temperature distribution remains within a safe range.

[0076] The visual feedback system uses a high-resolution camera to capture images of the weld area, extracting multimodal features (edges, corners, and textures), and dynamically adjusts feature weights based on the weld area's transparency and deformation characteristics. It uses an infrared thermal imager and laser displacement sensor to monitor deformation in real time, adjusting the registration results through a deformation compensation mechanism. An optimized RANSAC algorithm dynamically adjusts the threshold based on the density of feature point distribution and matching confidence, eliminating mismatches and improving matching accuracy. Finally, by calculating the transformation matrix, the alignment of the sensor and substrate is adjusted in real time to ensure the accuracy of the weld. The entire process optimizes welding accuracy through real-time image analysis and feedback mechanisms, ensuring high-quality and reliable packaging.

[0077] See also Figure 2 As shown, in S2, the method of aligning the absorbent sheet with the mounting hole based on the visual feedback system includes:

[0078] S21: Capturing an image of the welding area using a high-resolution industrial camera, and extracting multimodal features thereof using image processing technology, wherein the multimodal features include edge features, corner features, and texture features;

[0079] S22: monitoring the temperature distribution data and deformation data of the welding area in real time, and inputting the temperature distribution data and the deformation data into a deformation model constructed in advance to obtain a predicted deformation variable;

[0080] S23: Based on the predicted deformation, dynamically adjust the weights of different types of features in the multimodal features to obtain optimized feature points; specifically, in areas with a larger degree of deformation, texture features are preferentially used because texture features are insensitive to deformation; in areas with a smaller degree of deformation, edge and corner features are preferentially used because these features are more sensitive to local details. The formula for dynamically adjusting the weights of different types of features in the multimodal features is as follows:

[0081]

[0082] Among them, w iis the weight of the i-th feature, ΔD i is the deformation variable of the i-th feature area, and α is the adjustment coefficient. By dynamically adjusting the feature weights, the system can adapt to the deformation characteristics of the welding area and ensure the registration accuracy.

[0083] S24: registering the optimized feature points, eliminating mismatched points, and obtaining a preprocessed set of matching point pairs;

[0084] S25: Based on the set of matching point pairs, a geometric mapping relationship between the image of the component to be welded and the image of the substrate is calculated to obtain a transformation matrix;

[0085] S26: adjusting the position of the absorption sheet of the component to be welded to align with the position of the mounting hole of the substrate in real time according to the transformation matrix.

[0086] Optionally, in S22, the deformation model is constructed based on the physical model as follows:

[0087] Obtain the temperature change data ΔT and local deformation Δx of the welding area. Based on ΔT and Δx, a thermal-mechanical coupling deformation prediction model is established:

[0088]

[0089] Among them, α, β, and γ are thermal expansion coefficient, stress sensitivity factor, and transient deformation coefficient, respectively. ext is external stress.

[0090] Optionally, the deformation model can also be based on a deep learning model, using a deep learning algorithm (such as a convolutional neural network (CNN)) to learn deformation patterns from a large amount of temperature distribution and deformation data. After the model training is completed, new temperature distribution data can be input to predict the corresponding deformation. The training data used includes temperature distribution data, material property data, and actual deformation data. The mean square error (MSE) or mean absolute error (MAE) is used to measure the difference between the predicted value and the true value.

[0091] In addition, a deformation model can be constructed by combining physical models with deep learning models. This approach can improve the accuracy and generalization ability of the model by first making preliminary predictions using the physical model and then correcting them using the deep learning model.

[0092] In S23 of this embodiment, the method of dynamically adjusting the weights of different types of features in the multimodal features based on the predicted deformation amount also includes: for areas where the degree of deformation exceeds a preset deformation threshold, increasing the weight of texture features; for areas where the degree of deformation does not exceed the preset deformation threshold, increasing the weights of edge features and corner features.

[0093] The traditional RANSAC algorithm uses a fixed threshold to eliminate false matching points. However, in flexible scenes, due to material deformation and transparency, the fixed threshold may cause valid matching points to be mistakenly eliminated. To this end, the present invention introduces an adaptive threshold adjustment mechanism to dynamically adjust the threshold based on the distribution density of feature points and the matching confidence. Furthermore, in S24, the method for obtaining the preprocessed matching point pair set includes:

[0094] Based on the optimized feature points, the feature points are divided into multiple sub-areas, the number of feature points in each sub-area is counted, and the distribution density in each sub-area is calculated;

[0095] The optimized feature points are preliminarily matched using the RANSAC algorithm to obtain a set of matching point pairs. For each matching point pair, a matching score of each matching point pair is calculated based on the descriptor similarity of the feature points. At the same time, a geometric transformation fitting is performed on each matching point pair to calculate the fitting error.

[0096] Calculating a matching confidence according to the matching score and the fitting error, dynamically adjusting a threshold of a RANSAC algorithm according to the distribution density and the matching confidence, eliminating mismatched points using the adjusted threshold, and obtaining a preprocessed matching point pair set;

[0097] Each matching point pair includes a feature point in the image of the component to be welded and a feature point in the image of the substrate.

[0098] When the threshold is adjusted, the RANSAC algorithm will re-evaluate all matching point pairs and determine which matching point pairs are valid and which are mismatched based on the new threshold. Matching point pairs that were previously eliminated but meet the new threshold conditions will be retained; matching point pairs that were previously retained but do not meet the new threshold conditions will be eliminated again. At the same time, the system will recalculate the matching scores of the matching point pairs and screen them in combination with geometric consistency verification. Matching point pairs with higher matching scores will be retained first, while matching point pairs with lower scores may be eliminated. By dynamically adjusting the threshold, the system can optimize the matching results in real time based on the distribution density and confidence of the current matching point pairs.

[0099] For example, in areas with high feature point density, the threshold is lowered to more strictly eliminate false matches; in areas with low feature point density, the threshold is increased to avoid falsely eliminating valid matches. This dynamic adjustment mechanism can significantly improve matching accuracy, especially in flexible materials or complex scenes, effectively reducing the impact of false matches on the final result.

[0100] Furthermore, in S25, the method for obtaining the transformation matrix is as follows:

[0101] For a feature point whose local deformation amount is less than a deformation threshold, an affine transformation matrix is used to adjust the position of the absorber to align with the mounting hole;

[0102] For feature points whose local deformation amount is greater than or equal to the deformation threshold, the transmission transformation matrix is used to adjust the position of the absorption sheet to align with the mounting hole.

[0103] Furthermore, the method for obtaining the affine transformation matrix is as follows:

[0104] Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i :

[0105]

[0106] Use the following formula to solve the affine transformation matrix A:

[0107] A=QP T (PP T ) -1 .

[0108] Furthermore, the transmission transformation matrix is obtained as follows:

[0109] Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i :

[0110]

[0111] The transmission transformation matrix H is solved using the following formula:

[0112] H=argmin H ||Q-PH|| 2 .

[0113] If there's any misalignment between the absorber and the mounting hole, the system automatically adjusts the laser focus position or laser irradiation area to ensure the accuracy of the weld. Furthermore, the system monitors shape changes during the welding process to ensure the weld is uniform and meets pre-defined standards. If any anomalies are detected, the vision system provides timely feedback and adjusts welding parameters, such as laser power or focal size, to optimize weld quality. This process continuously optimizes welding accuracy through real-time image analysis and feedback mechanisms, ensuring high quality and reliability of the final package.

[0114] Example 2:

[0115] like Figure 3 and Figure 4 As shown, based on the same inventive concept as that of the first embodiment, the present invention further provides a laser transmission welding device for flexible circuit packaging, which includes: a substrate 1 , an absorbing sheet 2 , a welding gun 3 and a control unit 4 .

[0116] The base 1 is provided with a plurality of mounting holes 11 with a diameter of 0.1 mm to 0.3 mm, which reduces the risk of thermal stress concentration during welding, thereby avoiding film deformation due to thermal stress and ensuring film flatness;

[0117] The number of the absorption sheets 2 is the same as the number of the mounting holes 11 , and the absorption sheets 2 include a light-absorbing layer and a heat-conducting layer. The heat-conducting layer is attached to the component to be welded 8 , and the size of the absorption sheets 2 is smaller than the mounting holes 11 ;

[0118] The control unit 4 controls the connection of the welding gun 3 and simultaneously executes the steps of the laser transmission welding method for flexible circuit packaging described in Example 1, aligns the absorber 2 with the mounting hole 11, and sequentially irradiates the light-absorbing layer with a laser, so that the light-absorbing layer generates heat after absorbing the laser energy. With the cooperation of the light-absorbing layer and the mounting hole 11, local welding of the component to be welded 8 and the substrate 1 is achieved.

[0119] Preferably, the substrate 1 is made of a transparent flexible polymer (such as PET or PDMS) with high light transmittance and a thickness of 50 μm-200 μm.

[0120] The shape of the absorbent sheet 2 includes but is not limited to a circle, and can also be designed as a line, square or other geometric shapes. Preferably, in this embodiment, the absorbent sheet 2 is a micro double-layer cylindrical absorbent sheet with a diameter of 0.5mm-1mm and a thickness of 10μm-50μm.

[0121] Preferably, the light-absorbing layer includes, but is not limited to, carbon black, Clearweld material, graphene, or nanoparticle coatings, effectively absorbing laser light and converting the energy into heat. The thermally conductive layer is made of a thermally conductive material such as graphite, copper, aluminum, or silicon nitride. During welding, the thermally conductive layer disperses heat over a larger area, preventing localized overheating from damaging sensitive components.

[0122] Furthermore, the laser transmission welding device also includes an infrared thermal imager 5 and a laser displacement sensor 6 , which are respectively installed at designated positions close to the welding area and are both connected to the control unit 4 .

[0123] Furthermore, the laser transmission welding device further includes a camera device 7 , which is installed at a designated position close to the welding area and connected to the control unit 4 .

[0124] Preferably, the camera device 7 is a high-resolution industrial camera. The laser welding parameters of the welding gun 3 are set according to the material properties. A laser wavelength of 808 nm, 980 nm, or 1064 nm is selected, the laser power is adjusted to 2 W to 5 W, the focal diameter is adjusted to 0.2 mm to 0.5 mm, and the single-point irradiation time is set to 50 ms to 200 ms to ensure that both fusion and overheating damage are avoided during the welding process.

[0125] When the welding operation starts, the control unit 4 focuses the laser on the four corners of the component 8 to be welded and the mounting hole 1 area of the base 1 in turn, and irradiates point by point according to preset parameters. After the light-absorbing layer of the absorber 2 absorbs the laser energy, it heats up rapidly, generating local high temperature, causing the base material to melt and form a firm welding point with the sensor. At the same time, the thermal conductive layer disperses excess heat to prevent sensitive components from being damaged by heat. After all welding points are completed, the laser irradiation is stopped and the assembly is naturally cooled to room temperature to prevent deformation or detachment of the joint due to human intervention. After welding is completed, the assembly needs to undergo quality inspection, using tensile testing equipment to evaluate whether the strength of the welding point meets the design requirements, and a sealing test to check whether the package has problems such as air leakage and liquid leakage to ensure that the welding quality meets the actual application requirements.

[0126] Example 3:

[0127] The present invention also provides a computer storage medium storing a computer software product. The computer software product includes several instructions for enabling a computer device to execute the laser transmission welding method for flexible circuit packaging described in Example 1.

[0128] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0129] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0130] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0131] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0132] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A laser transmission welding method for flexible circuit packaging, characterized in that: The laser transmission welding method comprises the following steps: S1: a plurality of mounting holes are provided on the substrate, and an absorption sheet having the same number as the mounting holes is attached to the component to be welded, wherein the absorption sheet includes a light absorbing layer and a heat conducting layer; S2: Aligning the absorbent sheet with the mounting hole, sequentially irradiating the light-absorbing layer with a laser, causing the light-absorbing layer to absorb laser energy and generate heat, and achieving partial welding of the component to be welded and the substrate under the cooperation of the light-absorbing layer and the mounting hole; wherein the method of aligning the absorbent sheet with the mounting hole includes: S21: collecting a welding area image and extracting its multimodal features, wherein the multimodal features include edge features, corner features, and texture features; S22: monitoring the temperature distribution data and deformation data of the welding area in real time, and inputting the temperature distribution data and the deformation data into a deformation model constructed in advance to obtain a predicted deformation variable; S23: Dynamically adjusting the weights of different types of features in the multimodal features according to the predicted deformation amount to obtain optimized feature points; S24: registering the optimized feature points, eliminating mismatched points, and obtaining a preprocessed set of matching point pairs; S25: Based on the set of matching point pairs, a geometric mapping relationship between the image of the component to be welded and the image of the substrate is calculated to obtain a transformation matrix; S26: adjusting the position of the absorber of the component to be welded to align with the position of the mounting hole of the substrate in real time according to the transformation matrix; During the welding process, the temperature of the welding area is monitored, and it is determined whether the temperature of the component to be welded and the substrate is less than a set temperature threshold during the welding process. If the temperature is greater than or equal to the temperature threshold, the laser power is automatically adjusted.

2. The laser transmission welding method for flexible circuit packaging according to claim 1, characterized in that: In S24, the method for obtaining the preprocessed matching point pair set includes: Based on the optimized feature points, the feature points are divided into multiple sub-areas, the number of feature points in each sub-area is counted, and the distribution density in each sub-area is calculated; Performing preliminary matching on the optimized feature points to obtain a set of matching point pairs, and calculating a matching score for each matching point pair based on the descriptor similarity of the feature points; and performing geometric transformation fitting on each matching point pair to calculate the fitting error; Calculating a matching confidence according to the matching score and the fitting error, dynamically adjusting a threshold of a RANSAC algorithm according to the distribution density and the matching confidence, eliminating mismatched points using the adjusted threshold, and obtaining a preprocessed matching point pair set; Each matching point pair includes a feature point in the image of the component to be welded and a feature point in the image of the substrate.

3. The laser transmission welding method for flexible circuit packaging according to claim 1, characterized in that: In S25, the method for obtaining the transformation matrix is as follows: For a feature point whose local deformation amount is less than a deformation threshold, an affine transformation matrix is used to adjust the position of the absorber to align with the mounting hole; For feature points whose local deformation amount is greater than or equal to the deformation threshold, the transmission transformation matrix is used to adjust the position of the absorption sheet to align with the mounting hole.

4. The laser transmission welding method for flexible circuit packaging according to claim 3, characterized in that: The method for obtaining the affine transformation matrix is as follows: Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i : Use the following formula to solve the affine transformation matrix A: A=QP T (PP T ) -1 。 5. The laser transmission welding method for flexible circuit packaging according to claim 3, characterized in that: The method for obtaining the transmission transformation matrix is as follows: Define the number of matching point pairs in the matching point pair set as n, and record the matching point pairs as (p i ,q i ), where p i is the coordinate of the feature point in the image of the component to be welded, q i For the feature point coordinates in the base image, construct matrices P and Q, where matrix P contains all p i , the matrix Q contains all q i : The transmission transformation matrix H is solved using the following formula: H=argmin H ||Q-PH|| 2 。 6. The laser transmission welding method for flexible circuit packaging according to claim 1, characterized in that: In S22, the deformation model is constructed by: Obtain the temperature change data ΔT and local deformation Δx of the welding area. Based on ΔT and Δx, a thermal-mechanical coupling deformation prediction model is established: Among them, α, β, and γ are thermal expansion coefficient, stress sensitivity factor, and transient deformation coefficient, respectively. ext is external stress.

7. The laser transmission welding method for flexible circuit packaging according to claim 1, characterized in that: In S23, the formula for dynamically adjusting the weights of different features in the multimodal features is as follows: Among them, w i is the weight of the i-th feature, ΔD i is the deformation variable of the i-th feature region, and α is the adjustment coefficient.

8. The laser transmission welding method for flexible circuit packaging according to claim 1, characterized in that: In S23, the method of dynamically adjusting the weights of different types of features in the multimodal features based on the predicted deformation amount also includes: for areas where the degree of deformation exceeds a preset deformation threshold, increasing the weight of texture features; for areas where the degree of deformation does not exceed the preset deformation threshold, increasing the weights of edge features and corner features.

9. A laser transmission welding device for flexible circuit packaging, characterized in that: include: welding gun and control unit; The control unit controls the connection of the welding gun and synchronously executes the steps of the laser transmission welding method for flexible circuit packaging according to any one of claims 1 to 8.

10. The laser transmission welding device for flexible circuit packaging according to claim 9, characterized in that: The laser transmission welding device further comprises an infrared thermal imager and a laser displacement sensor, which are respectively installed at designated positions close to the welding area and are both connected to the control unit.

11. The laser transmission welding device for flexible circuit packaging according to claim 9, characterized in that: The laser transmission welding device further includes a camera device, which is installed at a designated position close to the welding area and is connected to the control unit.

12. A computer storage medium, characterized in that The computer storage medium stores a computer software product, and the computer software product includes several instructions for enabling a computer device to execute the laser transmission welding method for flexible circuit packaging according to any one of claims 1 to 8.

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