A method for bonding glass with OCA optical adhesive

Abstract

The application discloses a kind of OCA optical glue bonding methods for glass, comprising: obtaining OCA film molecular chain orientation spatial distribution map by fluorescence labeling molecule and polarized light technology;Utilize mixed solvent vapor induced measurement local swelling rate to obtain internal stress distribution map;Two distribution maps are associated and analyzed, and the mapping relationship of molecular chain orientation-stress distribution is obtained;According to the mapping relationship, directional electric field is applied to reconstruct the molecular chain arrangement of OCA film, and stress reconstruction data is obtained;Stress reconstruction data is used to determine bonding parameters and execute bonding process.The technical scheme of the present application can accurately detect and characterize the molecular chain orientation and internal stress distribution state in the OCA film on the nanoscale, reveal the correlation mechanism of microstructure and macroscopic performance, provide a scientific basis for optimizing the bonding process, effectively solve the problem of insufficient resolution of traditional detection methods, and significantly improve the quality control level and product reliability of optical glue bonding in large-size and curved display devices.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optical adhesive bonding of display devices, and in particular to a glass OCA (Optically Clear Adhesive) optical adhesive bonding method. BACKGROUND

[0002] Glass OCA (Optically Clear Adhesive) optical adhesive is a special double-sided optical adhesive without a substrate, mainly used for bonding between the touch panel and the protective glass or display module in high-end display devices. This optical adhesive has high light transmittance (usually greater than 95%), low haze, and a refractive index close to that of glass, and can effectively reduce light reflection and scattering, and improve display clarity and contrast. With the development of display technology towards lightness, thinness, high resolution and curvature, the industry has begun to develop OCA materials with special surface microstructures. Among them, nano-patterned OCA film refers to an optical adhesive film with a nano-scale precise pattern structure on the surface of a traditional OCA film. This microstructure design can significantly improve bubble discharge and enhance interface bonding strength during bonding.

[0003] The existing glass OCA optical adhesive bonding process usually includes cleaning, pressing, curing and other processes. With the increasing demand for bonding accuracy in high-end display devices, the pressing process has developed from simple flat pressing to precise roller pressing or ultrasonic vibration assisted bonding technology. These advanced technologies can significantly improve bonding uniformity and reduce bubble generation. However, in practical applications, it is found that when nano-patterned OCA film is used in combination with precise roller pressing or ultrasonic vibration assisted technology for bonding, the polymer chains will be oriented and arranged on a micron or even nanometer scale. This orientation phenomenon forms the elastic anisotropy of the material, i.e. the material exhibits different elastic properties in different directions. Due to this elastic anisotropy, local shear stress distribution abnormalities occur at the bonding interface, specifically some micro areas have stress concentration, while other areas have less stress. This uneven stress distribution cannot be detected by traditional thickness measurement or conventional tensile testing, because these methods have limited resolution and cannot capture nanoscale stress distribution changes. In actual product use, this uneven shear stress distribution can cause inconsistent touch response, local optical performance unevenness, and even cause micro-area peeling and other reliability problems during long-term use or environmental changes. These problems are particularly evident on large-size or curved display devices. Current detection methods such as interference fringe observation or Raman spectrum analysis cannot accurately identify and quantitatively describe this nanoscale elastic anisotropy due to their principle limitations, making this technical problem difficult to solve effectively for a long time. SUMMARY

[0004] The main purpose of the present application is to solve the technical problem of lacking effective detection and characterization of the elastic anisotropy and internal stress distribution of nano-patterned OCA film in the existing OCA optical adhesive bonding technology.

[0005] The first aspect of the present application provides an OCA optical adhesive bonding method for glass, comprising:

[0006] By introducing fluorescent labeling molecules into the OCA film, irradiating the OCA film with polarized light of different polarization directions, measuring the fluorescence intensity distribution, and obtaining the spatial distribution map of the molecular chain orientation of the OCA film;

[0007] Applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing the correspondence between the swelling rate and the internal stress, and obtaining the internal stress distribution map of the OCA film;

[0008] Correlation analysis is performed on the spatial distribution map of the molecular chain orientation of the OCA film and the internal stress distribution map of the OCA film, and a molecular chain orientation-stress distribution mapping relationship is obtained;

[0009] According to the molecular chain orientation-stress distribution mapping relationship, a directed electric field is applied to reconstruct the molecular chain arrangement of the OCA film, the stress change in the molecular chain rearrangement process is measured, and stress reconstruction data is obtained;

[0010] The stress reconstruction data is used to determine the bonding parameters of the OCA film and the glass substrate, and the bonding process of the OCA film and the glass substrate is performed.

[0011] Preferably, the method of introducing fluorescent labeling molecules into the OCA film, irradiating the OCA film with polarized light of different polarization directions, measuring the fluorescence intensity distribution, and obtaining the spatial distribution map of the molecular chain orientation of the OCA film comprises:

[0012] Argon gas containing naphthalene diimide derivatives is introduced into a sealed cavity, and the OCA film is placed in the sealed cavity, so that the naphthalene diimide derivatives are combined with the molecular chains of the OCA film through non-covalent interaction;

[0013] The OCA film is subjected to vacuum treatment to remove unbound naphthalene diimide derivatives;

[0014] Polarized light is applied to the OCA film, and the polarization direction is rotated at an angle interval of 5°, and the fluorescence intensity data at each angle is collected;

[0015] The fluorescence anisotropy value is calculated according to the fluorescence intensity data at each angle, and the spatial orientation angle of the molecular chain of the OCA film is determined;

[0016] The spatial orientation angle of the molecular chain of the OCA film is mapped to spatial coordinates to generate a spatial distribution map of the molecular chain orientation of the OCA film;

[0017] After all measurements were completed, the OCA film was treated at 50°C for at least 30 minutes to completely volatilize the naphthalene diimide derivative and restore the original properties of the OCA film.

[0018] Preferably, applying polarized light to the OCA film, rotating the polarized light direction at 5° intervals, and collecting fluorescence intensity data at each angle include:

[0019] A dual-wavelength polarized light system with a central wavelength of 350nm excitation light and 550nm emission light was used to synchronously illuminate the OCA film, and the dual-wavelength fluorescence intensity raw data at each rotation angle was recorded;

[0020] Calculating the fluorescence signals at different depths based on the dual-wavelength fluorescence intensity raw data, and constructing the fluorescence intensity attenuation function at different depths of the OCA film;

[0021] Reconstructing data in the depth direction using the fluorescence intensity attenuation function to obtain a fluorescence intensity distribution map for each depth layer;

[0022] The fluorescence intensity distribution diagrams of each depth layer are superimposed to obtain fluorescence intensity data at each angle.

[0023] Preferably, applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing a corresponding relationship between the swelling rate and the internal stress, and obtaining the internal stress distribution map of the OCA film includes:

[0024] Prepare a mixed solvent of tetrahydrofuran and isopropanol in a ratio of 3:7, and adjust the vapor concentration of the mixed solvent to 15% of the saturated vapor pressure at 25°C;

[0025] exposing the OCA film to the mixed solvent vapor, and recording thickness variation data of the OCA film in different regions;

[0026] Calculating the swelling rate of each region based on the thickness change data, and recording a curve of the swelling rate changing over time;

[0027] Fitting the curve of the swelling rate versus time using an exponential decay model to calculate the characteristic swelling time that characterizes the swelling kinetics of each region;

[0028] The surface stress distribution curve of the OCA film was drawn using the pre-established linear relationship between the characteristic swelling time and the internal stress.

[0029] Based on the stress distribution curve of the OCA film surface, a complete stress distribution map of the OCA film is generated through calculation and processing;

[0030] After the measurement and calculation are completed, the sample is placed in a vacuum environment at 50°C for at least 30 minutes to completely evaporate the solvent.

[0031] Preferably, exposing the OCA film to the mixed solvent vapor and recording thickness variation data of the OCA film in different regions includes:

[0032] Establish a mixed solvent vapor concentration gradient field that decreases from a central value of 15% to 10% and then increases to 20%;

[0033] Short pulses of solvent vapor were applied to the OCA film surface at 100ms intervals, and regional thickness data before and after the pulses were collected.

[0034] Arranging the regional thickness data in time series to obtain a dynamic thickness change curve;

[0035] The thickness variation of each region is calculated according to the dynamic thickness variation curve, and the thickness variation data of the OCA film in different regions are recorded.

[0036] Preferably, performing correlation analysis on the molecular chain orientation spatial distribution map of the OCA film and the stress distribution map within the OCA film to obtain a molecular chain orientation-stress distribution mapping relationship includes:

[0037] Applying a micro-area tensile load of 0.1-1.0 MPa to each region in the spatial distribution map of the molecular chain orientation of the OCA film, and recording the change in the orientation angle during the molecular chain rearrangement process;

[0038] Calculating the change rate of the orientation order parameter characterizing the order of the molecular chain according to the change in the orientation angle to obtain orientation order parameter distribution data;

[0039] The OCA film is heated to a temperature 10° C. lower than the glass transition temperature of the OCA film, and the stress relaxation time of each region is measured to obtain a stress relaxation curve.

[0040] Establishing a stress-orientation coupling response function that describes the relationship between molecular orientation and stress response according to the orientation order parameter change rate and the stress relaxation curve;

[0041] The stress-orientation coupling response function is analyzed in spatial correspondence with the stress distribution map in the OCA film to obtain a mapping relationship between molecular chain orientation and stress distribution.

[0042] Preferably, applying a directional electric field to reconstruct the molecular chain arrangement of the OCA film according to the molecular chain orientation-stress distribution mapping relationship, measuring the stress change during the molecular chain rearrangement process, and obtaining stress reconstruction data includes:

[0043] Identifying shear stress abnormal regions and molecular chain arrangement directions corresponding to the identified shear stress abnormal regions from the molecular chain orientation-stress distribution mapping relationship, applying an initial electric field at an angle of 45° to the molecular chain arrangement direction to each stress abnormal region, and measuring and recording the initial displacement angle of the molecular chain;

[0044] According to the initial displacement angle of the molecular chain, the angle between the electric field direction and the new orientation direction of the molecular chain is adjusted to 90°, and at the same time, the temperature of the OCA film is adjusted to 10°C below the glass transition temperature, and the data of the spatial orientation change of the molecular chain is recorded;

[0045] Based on the molecular chain spatial orientation change data, identifying and determining the molecular chain region that needs further adjustment, applying a reverse electric field to the region where the molecular chain spatial orientation changes after the initial electric field, causing the molecular chain to oscillate back and forth and rearrange, and recording the stress release time series during the oscillation process;

[0046] The oscillation period when the stress is minimum is determined according to the stress release time series, and the molecular chain is fixed in the state of the minimum stress oscillation period to obtain stress reconstruction data.

[0047] Preferably, applying a reverse electric field to the region where the molecular chain undergoes spatial orientation change after the initial electric field, so as to cause the molecular chain to swing back and forth and rearrange, and recording the stress release time series during the swinging process, comprises:

[0048] A high-speed photoelastic phase microscopy system capable of real-time detection of material stress states was used to continuously collect molecular chain swing data at a sampling rate of 1000 frames per second.

[0049] Calculating an optimal resonance frequency according to the molecular chain swing data, and adjusting the reverse electric field frequency to the calculated optimal resonance frequency;

[0050] Temperature cycle adjustment is performed within the range of glass transition temperature ±5℃ to maintain the activity of molecular chain movement;

[0051] The molecular chain motion process under the action of resonant electric field and temperature cycle is collected, and the stress release time series during the swing process is recorded.

[0052] Preferably, determining the lamination parameters between the OCA film and the glass substrate by using the stress reconstruction data and executing the lamination process between the OCA film and the glass substrate includes:

[0053] Converting the stress reconstruction data into a stress gradient distribution map, and determining the optimal initial contact point position of the OCA film according to the direction of the minimum stress gradient;

[0054] Starting from the optimal initial contact point position, the stress propagation law in the material is analyzed, the stress propagation direction in the bonding process is calculated, and the OCA film surface is divided into stress gradient control areas;

[0055] The surface of the glass substrate is subjected to a polarity gradient treatment that can produce a surface energy difference, and a surface energy distribution field that matches the stress gradient control area is constructed;

[0056] According to the surface energy distribution field, a stress gradient attenuation channel is designed to determine the stress release path in the bonding process;

[0057] According to the stress release path, a progressive pressure control strategy is adopted to form directional stress release in each stress gradient control area;

[0058] According to the propagation feedback of the directional stress release, the bonding pressure and speed are dynamically adjusted to complete the bonding process of the OCA film and the glass substrate.

[0059] Preferably, according to the surface energy distribution field, the stress gradient attenuation channel is designed to determine the stress release path in the bonding process, comprising:

[0060] According to the gradient direction of the surface energy distribution field, the stress release channel is divided into a first stress release channel that bears the main stress release function and a second stress release channel that bears the auxiliary stress release function;

[0061] The geometric characteristics of the first stress release channel, including the curvature radius and the extension direction, are calculated to construct the stress release main path;

[0062] According to the trend of the stress release main path, the branch position and the attenuation gradient of the second stress release channel are designed, wherein the branch position determines the connection point of the second stress release channel and the first stress release channel, and the attenuation gradient determines the weakening degree of stress in the second stress release channel;

[0063] According to the branch position and the attenuation gradient, the first stress release channel and the second stress release channel are connected to form a stress gradient attenuation network to determine the stress release path in the bonding process.

[0064] The technical solution provided in the embodiments of this application first achieves precise visualization of the orientation of the molecular chains in the OCA film by introducing fluorescent marker molecules and utilizing polarized light irradiation technology. Specifically, fluorescent molecules such as naphthalene diimide derivatives bind to the polymer chains through non-covalent interactions. When irradiated with light of different polarization directions, the polymer chain regions parallel to the polarization direction produce selective fluorescence enhancement. By rotating the polarization direction and recording the changes in fluorescence intensity, a spatial orientation distribution map of the polymer chains can be obtained. This method has a resolution of up to 0.5 microns and an orientation angle accuracy better than 0.5°, far exceeding traditional detection methods.

[0065] The method then applies mixed solvent vapor to the OCA film and uses the differences in the material's local swelling rates under the influence of the solvent to characterize the internal stress distribution. Regions with compressive stress experience an accelerated swelling rate, while regions with tensile stress experience a slower swelling rate. By measuring these swelling dynamics, a relationship between swelling rate and internal stress is established, allowing a complete map of the OCA film's internal stress distribution to be constructed. This method can reveal the true residual stress within the material with a resolution better than 0.1 MPa, and the measurement process is completely contactless.

[0066] Next, the method performed a correlation analysis between the spatial distribution of molecular chain orientation and the internal stress distribution. By applying micro-area tensile loads and temperature changes, the changes in orientation angle and stress relaxation characteristics during the molecular chain rearrangement process were observed, and a mapping relationship between molecular chain orientation and stress distribution was established. This mapping relationship reveals the essential connection between the material's microstructure and macroscopic properties, providing a theoretical basis for subsequent molecular chain reconstruction.

[0067] After obtaining this mapping relationship, the method reconstructs the molecular chain arrangement of the OCA film by applying a directional electric field. By applying an electric field at a specific angle to the stress anomaly region, the polymer chains realign, and then using a reverse electric field to induce the molecular chains to oscillate back and forth, searching for the molecular arrangement with minimal stress. This method differs from traditional passive detection by actively manipulating the material's molecular structure, fundamentally changing the microscopic cause of the stress anomaly.

[0068] Finally, the method uses the obtained stress reconstruction data to determine the bonding parameters of the OCA film and the glass substrate. By analyzing the stress gradient distribution, the optimal bonding path and pressure control strategy are designed, which achieves uniform stress release during the bonding process and greatly improves the bonding quality and product reliability.

[0069] This method achieves precise characterization and active regulation of the elastic anisotropy and internal stress distribution of nano-patterned OCA films by innovatively combining optical detection, materials science, and precision control technologies. Compared with traditional detection methods, this method not only solves the problem of insufficient resolution but also provides a complete solution from detection to optimization. Fluorescent labeling molecules and polarized light technology visualize the molecular chain orientation at the nanoscale; solvent vapor induction testing reveals hidden internal stress distribution; correlation analysis reveals the relationship between microstructure and macroscopic performance; electric field-assisted reconstruction technology actively changes the microstructure of the material; and finally, intelligent fitting path planning ensures that these micro-control effects can be translated into macroscopic product quality improvements. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0071] Figure 1 This is a schematic diagram of an embodiment of a method for bonding glass with OCA optical adhesive in an embodiment of the present invention.

[0072] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0074] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0075] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, and must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0076] An embodiment of the present application provides a method for bonding glass with OCA optical adhesive. Figure 1 A flow chart of a method for bonding glass with OCA optical adhesive provided in one embodiment of the present application. In this embodiment, the method includes:

[0077] See also Figure 1 By introducing fluorescent marker molecules into the OCA film, irradiating the OCA film with polarized light of different polarization directions, and measuring the fluorescence intensity distribution, the spatial distribution map of the molecular chain orientation of the OCA film is obtained;

[0078] In one embodiment of the present invention, the method of introducing fluorescent marker molecules into the OCA film, irradiating the OCA film with polarized light of different polarization directions, and measuring the fluorescence intensity distribution to obtain the spatial distribution map of the molecular chain orientation of the OCA film includes:

[0079] introducing argon gas containing a naphthalene diimide derivative into a sealed cavity, placing an OCA film in the sealed cavity, and allowing the naphthalene diimide derivative to bind to the OCA film molecular chain through non-covalent interaction;

[0080] performing vacuum treatment on the OCA film to remove unbound naphthalene diimide derivatives;

[0081] Applying polarized light to the OCA film, rotating the polarized light direction at 5° intervals, and collecting fluorescence intensity data at each angle;

[0082] Calculate the fluorescence anisotropy value according to the fluorescence intensity data at each angle to determine the spatial orientation angle of the OCA film molecular chain;

[0083] Performing spatial coordinate mapping on the spatial orientation angles of the OCA film molecular chains to generate a spatial distribution map of the OCA film molecular chain orientations;

[0084] After all measurements were completed, the OCA film was treated at 50°C for at least 30 minutes to completely volatilize the naphthalene diimide derivative and restore the original properties of the OCA film.

[0085] The following is a detailed description of the steps involved in the above embodiment:

[0086] In order to introduce argon gas containing naphthalene diimide derivatives into the sealed cavity, place the OCA film in the sealed cavity, and make the naphthalene diimide derivatives bind to the OCA film molecular chains through non-covalent interactions, it is necessary to first prepare an airtight quartz glass cavity equipped with gas inlet and outlet valves, a pressure gauge, and a temperature control system. The cut and surface-cleaned OCA film sample is placed on the sample stage in the center of the cavity, and then vacuumed to 10 -3 The chamber is then filled with high-purity argon containing a 0.001% concentration of a naphthalene diimide derivative. N,N'-bis(1-hexyl)-1,4,5,8-naphthalene diimide was chosen for its molecular end groups, which form strong π-π interactions with polar groups in the OCA film without forming covalent bonds. The chamber pressure was controlled at 101.3 kPa and the temperature was maintained at 25±0.5°C for 24 hours to allow the naphthalene diimide derivative molecules to diffuse fully and bind to the OCA film's molecular chains. The naphthalene diimide derivative molecules preferentially bind to regions with well-aligned molecular chains, forming complexes that function as fluorescent probes. This non-covalent binding does not alter the chemical structure or physical properties of the OCA film and serves only as a temporary marker. This fluorescent molecule was chosen for its large excitation-emission Stokes shift and high fluorescence quantum yield, providing sufficient signal intensity at low concentrations without permanently affecting the OCA material.

[0087] The OCA film was vacuum treated to remove the unbound naphthalene diimide derivatives. The labeled OCA film was transferred to a vacuum treatment chamber and the chamber was evacuated to 10 -4 Pa, the temperature is maintained at 30°C, and the treatment time is 2 hours. The vacuum treatment uses a pressure gradient to cause the naphthalene diimide derivative molecules that are not bound to the OCA film molecular chains to detach from the surface and shallow layers of the material. This selective vacuum treatment can effectively reduce background fluorescence interference and improve the signal-to-noise ratio of subsequent measurements. The temperature must be strictly controlled during vacuum treatment to avoid exceeding the glass transition temperature of the OCA material, otherwise it may cause changes in the molecular chain conformation and affect the accuracy of subsequent measurements. After treatment, the surface of the OCA film contains no free fluorescent molecules except the naphthalene diimide derivatives tightly bound to the molecular chains, ensuring that the fluorescence signal only reflects the spatial orientation information of the molecular chains.

[0088] Polarized light is applied to the OCA film, and the direction of the polarized light is rotated at an angle interval of 5°. When collecting the fluorescence intensity data at each angle, a confocal fluorescence microscope system equipped with a precisely rotatable polarizer and a high-sensitivity EMCCD detector is used. The excitation light source uses an ultraviolet laser with a wavelength of 350nm, which generates linearly polarized light through a λ / 4 wave plate and a polarizer, and the polarization degree is greater than 99.5%. The treated OCA film is fixed on a high-precision rotating platform, and then starting from 0°, the direction of the polarized light is rotated every 5° until a full angle scan of 180° is completed, for a total of 37 measurement angles. At each angle, the irradiation intensity is maintained at 0.5mW / cm 2 Fluorescence emission signals from naphthalene diimide derivatives at 550 nm were collected with an exposure time of 100 ms. To avoid fluorescence quenching, a 10-second interval was maintained between each acquisition to allow the fluorescent molecules to fully recover to their ground state. Five measurements were repeated at each angle and the average was taken to eliminate the effects of random noise and obtain accurate angle-dependent fluorescence intensity data. The 5° angle interval was chosen as a trade-off between measurement accuracy and efficiency, fully capturing the angular dependence of the molecular chain orientation distribution while maintaining a reasonable measurement time.

[0089] The fluorescence anisotropy value is calculated based on the fluorescence intensity data at each angle. When determining the spatial orientation angle of the OCA film molecular chain, the fluorescence anisotropy theory is applied for data processing. The fluorescence anisotropy value r is defined as the ratio of the difference in fluorescence intensity parallel to and perpendicular to the polarization direction to the total fluorescence intensity. For each measurement point, the fluorescence anisotropy parameter is fitted by analyzing the curve of fluorescence intensity changing with polarization angle. The relationship between fluorescence intensity I(θ) and polarization angle θ satisfies I(θ)=I0(1+r·cos 2 (θ-θ0)), where I0 is the average fluorescence intensity, r is the fluorescence anisotropy, and θ0 is the primary orientation angle of the molecular chain. Data from 37 angle points were fitted using the least squares method to obtain the r and θ0 values ​​for each spatial position. The fluorescence anisotropy r directly reflects the orientational order of the molecular chain; larger r values ​​indicate more ordered molecular chains in that region; θ0 indicates the dominant orientation direction. For regions with more complex orientation distributions, a two-parameter fitting model was used to analyze the molecular chains into two components: primary and secondary orientations, providing more accurate spatial orientation angle information.

[0090] The spatial orientation angles of the OCA film's molecular chains are mapped using spatial coordinates to generate a spatial distribution map of the OCA film's molecular chain orientation. A computer image processing system arranges the θ0 and r values ​​of each measurement point according to their actual spatial locations to construct a holographic distribution map. The spatial coordinate mapping uses a 1024×1024 pixel resolution, with each pixel corresponding to a 0.5μm×0.5μm area on the OCA film surface. The orientation angle θ0 is represented by hue coding, with 0-180° corresponding to a complete cycle of the color wheel. The anisotropy value r is encoded by brightness, with regions with high r values ​​appearing brighter. Furthermore, orientation vector lines are added to the distribution map, with their length proportional to the r value and their direction aligned with θ0, to intuitively display the spatial orientation information of the molecular chains. This multi-parameter spatial mapping method comprehensively displays the orientation distribution characteristics of the OCA film's molecular chains, including the degree of orientation, orientation direction, and spatial variation trends, providing detailed microstructural information for subsequent analysis. This high-resolution spatial distribution map accurately identifies areas of molecular orientation anomalies within the OCA film, such as stress concentration points and orientation mutations, and is crucial for guiding subsequent lamination processes.

[0091] After all measurements are completed, the OCA film is treated at 50°C for at least 30 minutes to completely volatilize the naphthalene diimide derivative and restore the film's original properties. The film is heated to 50°C in a precision temperature-controlled oven under nitrogen, with temperature fluctuations controlled within ±0.5°C. 50°C was chosen because it is above the sublimation temperature of the naphthalene diimide derivative but below the glass transition temperature of the OCA film, ensuring effective volatilization of the fluorescent molecules without altering the OCA material's microstructure. The 30-minute treatment time is the minimum required for complete volatilization, as determined by the fluorescence intensity decay curve. Extending the treatment time does not provide additional benefits and may increase energy consumption. The treated OCA film is then tested for transmittance to confirm complete volatilization of the naphthalene diimide derivative and restoration of transmittance to its original level (>99.5%). This clearing step ensures that the fluorescent labeling serves only as a temporary, traceless analytical tool and does not adversely affect the optical properties, bonding performance, and long-term stability of the OCA film, enabling it to maintain its original optical transparency and bonding properties, meeting the stringent requirements of high-end display devices.

[0092] In one embodiment of the present invention, applying polarized light to the OCA film, rotating the polarized light direction at 5° intervals, and collecting fluorescence intensity data at each angle include:

[0093] A dual-wavelength polarized light system with a central wavelength of 350nm excitation light and 550nm emission light was used to synchronously illuminate the OCA film, and the dual-wavelength fluorescence intensity raw data at each rotation angle was recorded;

[0094] Calculating the fluorescence signals at different depths based on the dual-wavelength fluorescence intensity raw data, and constructing the fluorescence intensity attenuation function at different depths of the OCA film;

[0095] Reconstructing data in the depth direction using the fluorescence intensity attenuation function to obtain a fluorescence intensity distribution map for each depth layer;

[0096] The fluorescence intensity distribution diagrams of each depth layer are superimposed to obtain fluorescence intensity data at each angle.

[0097] The following is a detailed description of the steps involved in the above embodiment:

[0098] The OCA film was simultaneously illuminated using a dual-wavelength polarized light system with excitation light at a central wavelength of 350 nm and emission light at a central wavelength of 550 nm. Raw fluorescence intensity data at each rotation angle was recorded using a confocal fluorescence microscope equipped with a dual-channel detector. This system consists of a precision rotating polarizer, a 350 nm UV laser source, a 550 nm filter set, and a high-sensitivity photomultiplier tube detector. A dual-wavelength polarized light system is a polarization optical system capable of simultaneously generating and detecting two different wavelengths of light: 350 nm as the excitation wavelength for the fluorescent molecules of the naphthalene diimide derivative, and 550 nm as the primary fluorescence emission wavelength. During the measurement, the marked OCA film was placed on a precision rotating stage. Starting at 0°, the polarizer was rotated in 5° increments. The sample was illuminated for 5 seconds at each angular position, while the 350 nm reflectance signal and 550 nm fluorescence signal were simultaneously recorded at different depths. For a typical 200 μm thick OCA film, 100 layers of data were acquired at 2 μm increments along the z-axis to generate a complete 3D fluorescence distribution dataset. The selection of these two specific wavelengths, 350nm and 550nm, is based on the optimal excitation-emission spectral characteristics of naphthalene diimide derivatives. While ensuring sufficient fluorescence intensity, it can minimize background interference and improve the signal-to-noise ratio by at least 30dB, ensuring accurate detection of deep structures.

[0099] Based on the dual-wavelength fluorescence intensity raw data, the fluorescence signals at different depths are calculated. When constructing the fluorescence intensity attenuation function for the OCA film at different depths, an optical path correction algorithm is used to process the raw data. The fluorescence intensity attenuation function is a mathematical expression that describes how the fluorescence signal varies with depth in the OCA film, reflecting the absorption and scattering characteristics of light during propagation through the material. First, the 350nm reflection signal is used to determine the precise surface location and thickness reference point. Then, the 550nm fluorescence intensity I(x,y,z) at each spatial location (x,y,z) is normalized to eliminate the effects of laser power fluctuations and detector sensitivity non-uniformity on the measurement results. Next, the variation of the fluorescence intensity I at each (x,y) location with depth z is analyzed to extract the attenuation coefficient α(x,y). For regions with different orientations in the OCA film, the fluorescence signal exhibits different attenuation characteristics along the depth direction: regions where the molecular chains are parallel to the direction of light propagation experience slower fluorescence intensity decay, while regions where the molecular chains are perpendicular to the direction of light propagation experience faster attenuation. Taking actual measurement as an example, in a 25mm×25mm OCA sample, the attenuation coefficient α in the central area is about 0.015μm -1 , while the edge area is about 0.035μm -1 This difference directly reflects the spatial variation of the molecular chain orientation. Through this analysis, not only the surface molecular orientation information is obtained, but also the three-dimensional characteristics of the internal molecular arrangement can be revealed.

[0100] The fluorescence intensity attenuation function is used to reconstruct data in the depth direction. When obtaining the fluorescence intensity distribution map of each depth layer, the inverse convolution algorithm is applied to perform optical depth correction. Data reconstruction refers to the use of measurement data and optical propagation models to restore the true fluorescence distribution state inside the material. In the specific operation, the refractive index distribution n(x, y, z) of the OCA film is first determined. For typical OCA materials, the n value is approximately 1.48 to 1.52. Then, considering the path change and intensity attenuation of light when propagating in different refractive index regions, an optical path-intensity mapping relationship is established. For each depth layer z, the Richardson-Lucy iterative algorithm is used to perform 20 iterative calculations to eliminate the shielding effect of the upper structure on the lower layer fluorescence signal. In this process, special attention is paid to correcting the optical path distortion to ensure that the spatial resolution remains consistent throughout the depth range. For an OCA film with a thickness of 200μm, the lateral resolution is maintained at 0.5μm and the depth resolution is 2μm. Through this depth data reconstruction, the molecular orientation characteristics of different depth layers in the OCA film can be accurately distinguished. For example, there may be highly oriented areas within 50μm of the surface due to the influence of the manufacturing process, while the middle 100μm area may show a more random orientation distribution.

[0101] The fluorescence intensity distribution map of each depth layer is superimposed, and when the fluorescence intensity data at each angle is obtained, the weighted integration method is used to achieve dimensionality reduction of the spatial data. Superposition processing refers to the calculation process of converting three-dimensional spatial distribution data into two-dimensional plane data. The purpose is to integrate the information of each depth layer to form an overall orientation feature characterization. In the specific implementation, for each plane position (x, y), the fluorescence intensity value is weighted and summed along the depth direction z, and the weight coefficient w(z) is proportional to the contribution of the depth layer to the overall optical and mechanical properties. For the OCA film, the weight coefficient of the surface and near-interface area (0-30μm and 170-200μm) is set to 1.5, while the weight coefficient of the middle area (30-170μm) is set to 1.0. This weighting scheme reflects the dominant role of the interface area in the bonding process. After the superposition is completed, the fluorescence intensity data at 36 polarization angles (0° to 175°) are Fourier analyzed to extract the angle-dependent characteristics and form a complete polarization angle-fluorescence intensity response curve. Compared with simple averaging, this overlay processing method can more accurately reflect the overall molecular chain orientation distribution of the OCA film, especially for samples with uneven orientation in the depth direction. For example, OCA films for large-size display panels that have undergone a complex rolling process can have surface and internal molecular orientation differences of more than 30°. Only through this weighted overlay method can their bonding performance be fully evaluated.

[0102] Please continue reading Figure 1 , applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing a corresponding relationship between the swelling rate and the internal stress, and obtaining an internal stress distribution map of the OCA film;

[0103] In one embodiment of the present invention, applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing a corresponding relationship between the swelling rate and the internal stress, and obtaining the internal stress distribution map of the OCA film includes:

[0104] Prepare a mixed solvent of tetrahydrofuran and isopropanol in a ratio of 3:7, and adjust the vapor concentration of the mixed solvent to 15% of the saturated vapor pressure at 25°C;

[0105] exposing the OCA film to the mixed solvent vapor, and recording thickness variation data of the OCA film in different regions;

[0106] Calculating the swelling rate of each region based on the thickness change data, and recording a curve of the swelling rate changing over time;

[0107] Fitting the curve of the swelling rate changing with time according to an exponential decay model, and calculating the swelling characteristic time characterizing the swelling kinetics of each region;

[0108] The surface stress distribution curve of the OCA film was drawn using the pre-established linear relationship between the characteristic swelling time and the internal stress.

[0109] Based on the stress distribution curve of the OCA film surface, a complete stress distribution map of the OCA film is generated through calculation and processing;

[0110] After the measurement and calculation are completed, the sample is placed in a vacuum environment at 50°C for at least 30 minutes to completely evaporate the solvent.

[0111] The following is a detailed description of the steps involved in the above embodiment:

[0112] To prepare a 3:7 tetrahydrofuran / isopropanol solvent mixture and adjust the vapor concentration to 15% of the saturated vapor pressure at 25°C, a precision chemical dispensing system and a temperature-controlled vapor concentration control device were required. First, analytical grade (≥99.5%) tetrahydrofuran and isopropanol were used to prepare the solvent mixture using a precise volumetric mixing method: 300ml of tetrahydrofuran and 700ml of isopropanol were measured and mixed at a low temperature (15°C) to prevent solvent evaporation and potential ratio deviation. The 3:7 ratio of tetrahydrofuran to isopropanol was precisely calculated to be the optimal combination. Tetrahydrofuran has strong solubility, effectively penetrating the amorphous regions of the OCA film, while isopropanol has moderate polarity, allowing for selective interaction with polar groups in the OCA film. This solvent mixture exhibits differential swelling effects on regions with different stress states within the OCA film: regions with compressive stress swell faster, while regions with tensile stress swell slower. The mixed solvent is placed in a constant-temperature evaporator. A precision flow control system mixes the evaporated solvent vapor with dry nitrogen at a specific ratio, ensuring that the concentration of the solvent vapor entering the test chamber is precisely controlled to 15% of the saturated vapor pressure (relative error <±0.5%). The operating temperature of 25°C is chosen because at this temperature, the vapor pressure of the mixed solvent is moderate, providing sufficient swelling without causing excessive swelling and deformation of the OCA film. A concentration of 15% of the saturated vapor pressure represents the optimal balance between swelling rate and structural stability. At this concentration, solvent molecules can selectively penetrate the OCA material without disrupting its basic structure.

[0113] The OCA film is exposed to the mixed solvent vapor, and a real-time optical interferometry thickness measurement system is used for high-precision monitoring while recording the thickness variation data of the OCA film in different regions. This system consists of a white-light interferometer, a high-resolution CCD camera, and a computer image processing system, with a spatial resolution of 0.2μm and a thickness measurement accuracy better than 50nm. The OCA film sample is fixed on the sample stage of the test chamber to ensure that the sample surface is flat and free of noticeable warping. The test chamber is made of optical-grade quartz glass, with an optical window on the top for interferometric measurement. The interior of the chamber is maintained at a constant temperature of 25±0.1°C. The solvent vapor introduction system is activated to quickly reach the set solvent vapor concentration in the chamber. At the same time, the interferometric thickness measurement system is activated to collect thickness data for the entire field of view of the OCA film at a frequency of 10Hz. The typical measurement area is 10mm×10mm, divided into 100×100 measurement points, forming a complete spatial distribution map of the thickness variation. In actual measurements, with the initial thickness set as the zero reference point, the OCA film exhibited different swelling behaviors in different regions as the exposure time to solvent vapor increased. For a standard 200μm-thick OCA film, after 60 minutes of exposure to 15% mixed solvent vapor, the thickness of the stress-normalized region increased by approximately 3-5μm, while the thickness of the stress-concentrated region increased by up to 7-10μm. This spatial difference directly reflects the uneven distribution of stress within the OCA film, providing key data for subsequent stress analysis.

[0114] The swelling rate for each region was calculated based on the thickness change data. Numerical differentiation and smoothing algorithms were applied to the data analysis when recording the swelling rate versus time curve. The swelling rate is defined as the increase in OCA film thickness per unit time, expressed in μm / min, and directly reflects the diffusion and swelling dynamics of solvent molecules in the OCA material. For each measurement point (i, j), thickness data from five consecutive time points were collected, and the swelling rate v(i, j, t) at that time point was calculated using the central difference method. To eliminate the influence of measurement noise, the calculated rate data was smoothed using the Savitzky-Golay filter algorithm. The filter window width was set to 11 data points, and the polynomial order was 3. This smoothing algorithm not only preserves the true trend of the swelling rate change but also effectively suppresses random noise. The processed swelling rate data for each region were arranged in chronological order to generate a swelling rate versus time curve. A typical swelling rate curve exhibits three distinct phases: an initial rapid rise (0-5 minutes), during which the swelling rate rapidly increases, reflecting the surface adsorption of solvent molecules; a mid-stage plateau (5-15 minutes), during which the swelling rate reaches a maximum and remains relatively stable, reflecting the steady-state penetration of solvent molecules; and a late decay phase (>15 minutes), during which the swelling rate gradually decreases, reflecting the deceleration of the material's swelling as it approaches saturation. In actual OCA film samples, regions with different stress states exhibit significantly different swelling rate curves: the maximum swelling rate in the high-pressure stress region can reach 0.25 μm / min, while the high-tensile stress region is only around 0.12 μm / min.

[0115] The swelling rate versus time curve was fitted to an exponential decay model. The characteristic swelling time, which characterizes the swelling kinetics of each region, was calculated using a nonlinear least squares method. The characteristic swelling time is a physical quantity that describes the decay rate of a material's swelling process. Measured in minutes, smaller values ​​indicate faster swelling rate decay, reflecting the tightness of the molecular chain arrangement and the stress state within the material. The exponential decay model is a classic model for describing the swelling kinetics of polymer materials, accurately capturing the entire decay process of the swelling rate from peak to equilibrium. Specifically, a three-parameter exponential decay function was used to fit the swelling rate data in the late decay phase (t > 15 minutes) to extract the characteristic swelling time τ. For a typical OCA film, the characteristic swelling time is approximately 12-15 minutes in normal regions, while the τ value in stress-abnormal regions ranges from 6-20 minutes. The compressive stress region has a smaller τ value (6-10 minutes) and the tensile stress region has a larger τ value (15-20 minutes). Through this fitting analysis, the complex swelling rate curve is simplified to a single parameter τ, which not only retains the key information of the stress state but also facilitates subsequent quantitative analysis and spatial mapping. The exponential decay model is chosen rather than other mathematical models because it has high fitting accuracy (coefficient of determination R 2>0.98), and has a clear physical meaning. The τ value directly corresponds to the molecular chain relaxation characteristics and internal stress state of the polymer material.

[0116] When drawing the stress distribution curve of the OCA film surface using the pre-established linear correspondence between the characteristic swelling time and the magnitude of the internal stress, spatial interpolation and pseudo-color mapping techniques are used for data visualization. The pre-established linear correspondence refers to the quantitative relationship between the characteristic swelling time τ and the absolute stress value σ measured by the standardized stress calibration sample, that is, σ=A·τ+B, where A and B are calibration coefficients. For the OCA material used in this embodiment, A=-0.15MPa / min, B=2.5MPa. The characteristic swelling time τ(i,j) of each measuring point (i,j) is substituted into the relationship, and the stress value σ(i,j) at the corresponding position is calculated to form a complete stress numerical matrix. The bicubic spline interpolation algorithm is then used to expand the 100×100 discrete stress data to 500×500 high-resolution data to improve the smoothness and visual effect of the stress distribution map. Finally, a "hot and cold" pseudo-color mapping scheme (blue represents compressive stress, red represents tensile stress, and green represents neutral stress) was used to convert the stress values ​​into an intuitive color image. Contour lines were superimposed to represent areas of equal stress magnitude, forming a stress distribution curve on the OCA film surface. This curve visually displays the spatial characteristics of the stress distribution on the OCA film surface, including stress magnitude (typically within a range of ±1.5 MPa), stress gradient, and areas of stress concentration, providing a valuable reference for subsequent lamination process optimization.

[0117] Based on the surface stress distribution curve of the OCA film, a complete internal stress distribution map of the OCA film is generated through computational processing. The stress field is reconstructed using elastic equilibrium equations and boundary constraints. A complete internal stress distribution map of the OCA film represents a dataset characterizing the full three-dimensional stress state within the OCA film, including the components of the stress tensor and their spatial distribution. Based on the boundary conditions provided by the surface stress distribution curve and the mechanical parameters of the material (Young's modulus E = 10 MPa, Poisson's ratio ν = 0.45), the elastic equilibrium equations are solved using finite element analysis to calculate the internal stress field distribution of the OCA film. Specifically, the OCA film is divided into 50×50×20 hexahedral mesh elements. The stress equilibrium equation is solved for each element to obtain six independent components of the stress tensor (three normal stresses and three shear stresses). Principal stress analysis is then performed to extract the directions and magnitudes of the three principal stresses at each spatial location. The maximum shear stress is used as the primary evaluation metric to generate the internal stress distribution map of the OCA film. Compared to the surface stress distribution curve, the internal stress distribution map provides more comprehensive three-dimensional stress information, enabling the identification of hidden stress concentration areas and stress singularities. For example, in some areas where the surface stress appears normal, there may be significant stress mutations inside. These features can only be accurately captured through a complete internal stress distribution map.

[0118] After the measurement and calculation are completed, the solvent is completely evaporated by treating it in a vacuum environment at 50°C for at least 30 minutes, and then a precision vacuum drying system is used for post-processing. The system consists of a vacuum chamber, a multi-stage vacuum pump group, a precision temperature control system and a residual gas analyzer, which can create a high vacuum (<10 -3 The OCA film sample that has completed the swelling test is placed in a vacuum chamber and first evacuated to 10 -2 Pa, removing surface and shallow solvent molecules, then raising the temperature to 50°C and maintaining this temperature while continuing to evacuate for at least 30 minutes. The choice of 50°C as the optimal treatment temperature was precisely calculated: on the one hand, this temperature is higher than the boiling points of tetrahydrofuran (boiling point 66°C) and isopropyl alcohol (boiling point 82.5°C) at low pressure, significantly accelerating the volatilization rate of solvent molecules; on the other hand, it is lower than the glass transition temperature of the OCA material (typically >70°C), avoiding molecular chain rearrangement and stress relaxation caused by high temperatures, ensuring that the measured stress distribution information is not altered by post-treatment. After treatment, the residual solvent content in the OCA film was measured using an infrared spectrometer, confirming that the residual concentrations of tetrahydrofuran and isopropyl alcohol were both below 10 ppm, indicating that the solvents had completely evaporated and the OCA film had restored its original physical and chemical properties.

[0119] In one embodiment of the present invention, exposing the OCA film to the mixed solvent vapor and recording thickness variation data of the OCA film in different regions includes:

[0120] In a closed room, a mixed solvent vapor concentration gradient field is established, which decreases from the central value of 15% to 10% and increases to 20% outward;

[0121] Short pulses of solvent vapor were applied to the OCA film surface at 100ms intervals, and regional thickness data before and after the pulses were collected.

[0122] Arranging the regional thickness data in time series to obtain a dynamic thickness change curve;

[0123] The thickness variation of each region is calculated according to the dynamic thickness variation curve, and the thickness variation data of the OCA film in different regions are recorded.

[0124] The following is a detailed description of the steps involved in the above embodiment:

[0125] A multi-zone vapor control system was used to establish a mixed solvent vapor concentration gradient field, decreasing from a central value of 15% to 10% and increasing to 20% outward. The system consists of a cylindrical quartz glass enclosure (300 mm diameter, 100 mm height), a multi-channel vapor supply, and a concentration monitoring system. Five concentric annular zones were set up within the enclosure: Zones A, B, C, D, and E, from the center outward. Zone A (60 mm diameter) maintained a baseline concentration of 15%. Zone B (60-120 mm diameter) formed a transition concentration range of 13-17%. Zone C (120-180 mm diameter) formed the downward transition concentration range of 10-13% and the upward transition concentration range of 17-20%. Zone D (180-240 mm diameter) maintained stable concentrations of 10% and 20%. Zone E (240-300 mm diameter) served as a buffer zone. A mixed solvent vapor concentration gradient field refers to a distribution of vapor with varying concentrations at different locations in space, resulting in a concentration trend that varies from the center outward. Solvent vapor of varying concentrations is introduced into each region through multiple precision microfluidic valves, while a ring-shaped microfan (speed <100 rpm) at the bottom of the chamber generates a slow airflow to maintain a stable concentration gradient. Real-time concentration monitoring utilizes five optical absorption concentration sensors with an accuracy of ±0.2%. This concentration gradient design exposes different regions of the OCA film to varying solvent vapor concentrations simultaneously, enabling the material's response characteristics under a variety of swelling conditions to be measured simultaneously. This significantly improves testing efficiency and more accurately reflects the differences in the OCA film's sensitivity to changes in solvent concentration, which are directly related to the molecular chain arrangement and stress state within the material.

[0126] A pulse jet-interferometer real-time monitoring system was used to apply short pulses of solvent vapor to the OCA film surface at 100ms intervals. Thickness data was collected before and after the pulses using a combined pulse jet-interferometer real-time monitoring system. Short solvent vapor pulses are extremely short-duration, high-concentration solvent vapor injections that can produce transient swelling responses and enhance swelling differences between different regions of the material. The system consists of five independently controllable micro-piezoelectric atomizer nozzles (50mm apart), a high-speed interferometer, and a synchronous trigger controller. The micro-piezoelectric atomizer nozzles atomize the solvent mixture into droplets less than 5μm in diameter. By precisely controlling the injection time (5ms on-time) and pressure (0.2MPa), vapor pulses with a duration of 100ms were generated. A 900ms interval between pulses ensured complete vapor diffusion across the OCA film surface, avoiding localized vapor accumulation. The high-speed interferometer, with a sampling rate of 1000Hz, collected 10 frames of thickness data before and after each pulse, with a spatial resolution of 0.5μm × 0.5μm and a thickness resolution of 10nm. For a standard test area (10 mm x 10 mm), a total of 100 measurement points were set, forming a 10 x 10 measurement matrix. Solvent vapor short pulse technology offers significant advantages over continuous immersion methods: it rapidly stimulates the material's transient swelling response, converting small differences in internal stress into measurable thickness change signals. At the same time, it avoids the molecular chain rearrangement and stress relaxation that can result from prolonged solvent exposure, preserving the material's original stress state.

[0127] The thickness data for the region is arranged in a time series to obtain a dynamic thickness variation curve, using data time alignment and sequence reconstruction techniques. A dynamic thickness variation curve is a continuous function image that describes the temporal variation of the OCA film thickness, reflecting the dynamic swelling process of the material under the action of solvent vapor. First, the thickness data for each measurement point (i, j) is time-stamped to ensure that the data is precisely synchronized with the pulse trigger time, with a time resolution of 1ms. Then, the 20 frames of thickness data collected within each pulse cycle (a total of 1000ms) are arranged in chronological order to form discrete thickness-time data points. Next, a cubic spline interpolation algorithm is used to connect the discrete data points into a continuous thickness variation curve, with 1000 interpolation points corresponding to a time resolution of 1ms. For each measurement point, the data from 100 pulse cycles are superimposed and averaged to obtain a high signal-to-noise ratio thickness variation curve with a 10-fold reduction in noise level. This time series processing method not only improves the measurement accuracy and reliability, but also captures the rapid response characteristics of the OCA film under the action of solvent pulses, such as the initial swelling rate, peak swelling amount and swelling decay rate. These characteristics are closely related to the molecular chain arrangement and internal stress state of the material.

[0128] The thickness variation of each region is calculated according to the dynamic thickness variation curve. When recording the thickness variation data of the OCA film in different regions, the peak extraction and spatial mapping methods are used for data processing. The thickness variation is defined as the maximum thickness increase of the OCA film after the solvent vapor pulse, in nanometers, which directly reflects the material's response sensitivity to the solvent. In the specific implementation, for each measurement point (i, j) of the dynamic thickness variation curve, the baseline thickness h0(i, j) before the pulse and the maximum thickness h0(i, j) after the pulse are determined. max (i, j), calculate the thickness change Δh(i, j)=h max (i,j)-h0(i,j). To improve measurement accuracy, the thickness variation at each measurement point was measured five times and the average value was taken. The thickness variations at all measurement points were then arranged by spatial position to form a two-dimensional thickness variation distribution map. Pseudo-color coding (blue represents small variations, red represents large variations) was used to visually display the spatial distribution characteristics. For a typical OCA film sample, under the action of a 15% solvent vapor pulse, the thickness variation in the normal area is approximately 50-70nm, while the stress-abnormal area can reach 80-120nm. This significant difference makes the internal stress distribution characteristics clearly discernible. The thickness variation data has a spatial resolution of 0.5mm and covers the entire 10mm×10mm test area. It can accurately capture the detailed characteristics of the stress distribution, such as stress gradients, stress concentration points, and stress boundaries, providing a reliable basis for accurately evaluating the stress state of the OCA film and predicting the bonding performance.

[0129] Please continue reading Figure 1 , performing a correlation analysis on the spatial distribution map of the molecular chain orientation of the OCA film and the stress distribution map within the OCA film to obtain a molecular chain orientation-stress distribution mapping relationship;

[0130] In one embodiment of the present invention, the performing of correlation analysis on the molecular chain orientation spatial distribution map of the OCA film and the stress distribution map within the OCA film to obtain a molecular chain orientation-stress distribution mapping relationship includes:

[0131] Applying a micro-area tensile load of 0.1-1.0 MPa to each region in the spatial distribution map of the molecular chain orientation of the OCA film, and recording the change in the orientation angle during the molecular chain rearrangement process;

[0132] Calculating the change rate of the orientation order parameter characterizing the order of the molecular chain according to the change in the orientation angle to obtain orientation order parameter distribution data;

[0133] The OCA film is heated to a temperature 10° C. lower than the glass transition temperature of the OCA film, and the stress relaxation time of each region is measured to obtain a stress relaxation curve.

[0134] Establishing a stress-orientation coupling response function that describes the relationship between molecular orientation and stress response according to the orientation order parameter change rate and the stress relaxation curve;

[0135] The stress-orientation coupling response function is analyzed in spatial correspondence with the stress distribution map in the OCA film to obtain a mapping relationship between molecular chain orientation and stress distribution.

[0136] The following is a detailed description of the steps involved in the above embodiment:

[0137] A high-precision micromechanical testing system was used to apply a micro-area tensile load of 0.1-1.0 MPa to each region in the spatial distribution of molecular chain orientation in the OCA film and record the changes in orientation angle during molecular chain rearrangement. This system consists of a piezoelectric nanopositioner, a micro-strain loading device, and an in-situ polarized fluorescence microscope. Micro-area tensile loading refers to tensile stress applied to a very small area (approximately 100 μm × 100 μm) on the OCA film surface to induce local molecular chain rearrangement. During the test, 100 test points were uniformly selected on the OCA film surface, covering different molecular chain orientation regions. Then, a gradually increasing tensile load was applied to each test point, starting from 0.1 MPa and increasing in steps of 0.1 MPa to 1.0 MPa, with each load level maintained for 60 seconds. Simultaneously, the molecular chain orientation changes were recorded in real time using polarized fluorescence microscopy at a sampling frequency of 10 Hz. The molecular chain orientation angle was determined by fluorescence anisotropy measurement, and the orientation angle θ was recorded at each load level. For a typical OCA film, the orientation angle changes by approximately 2-5° under a load of 0.1 MPa, while at a load of 1.0 MPa, the change can reach 15-30°. The load range of 0.1-1.0 MPa is determined based on the elastic properties of the OCA material: below 0.1 MPa, the molecular chain response is not obvious, making it difficult to obtain valid data; above 1.0 MPa, the material may enter the yield zone, resulting in irreversible deformation, affecting measurement accuracy. This micro-area testing method avoids the uneven deformation that may be introduced by large-scale stretching, and can accurately obtain the response characteristics of local molecular chains to stress, providing key data for understanding the micromechanical behavior of OCA films.

[0138] According to the change in the orientation angle, the rate of change of the orientation order parameter that characterizes the order of the molecular chain is calculated. When the orientation order parameter distribution data is obtained, the orientation order statistical analysis method is applied to process the measurement data. The orientation order parameter (S) is a physical quantity that describes the degree of order of the molecular chain arrangement. The value range is -0.5 to 1.0. The closer the value is to 1, the more ordered the molecular chain arrangement is and the more parallel it is to the dominant direction. The closer the value is to 0, the more random the arrangement is. A negative value indicates that the molecular chain is arranged perpendicular to the reference direction. The rate of change of the orientation order parameter (dS / dσ) is defined as the rate at which the orientation order parameter S changes with stress σ, and the unit is MPa-1 , which directly reflects the sensitivity of molecular chain rearrangement. The calculation process first converts the measured orientation angle θ to the orientation order parameter S, which is given by S = (3cos 2 θ - 1) / 2, where θ is the angle between the molecular chain and the reference direction. Then, for each test point, an S-σ curve (S is the orientation order parameter and σ is the applied stress) is plotted, and the slope of the curve in different stress intervals, i.e., the rate of change of the orientation order parameter dS / dσ, is calculated. For a typical OCA film, the dS / dσ value in the highly oriented region of the molecular chain is small (about 0.05-0.1 MPa -1 ), indicating that the molecular arrangement in these regions is relatively stable; while the dS / dσ value in the stress anomaly region is larger (about 0.2-0.4 MPa -1 ), indicating that the molecular chains in these regions are more sensitive to external forces and prone to rearrangement. By mapping the dS / dσ values of all test points in space, a complete orientation order parameter change rate distribution map is formed, which directly shows the spatial difference in the stress response of the molecular chains of the OCA film. This analysis method based on the orientation order parameter provides more in-depth microstructure information than simple angle changes, can accurately characterize the order and stability of the molecular chains, and provides a scientific basis for predicting the mechanical behavior of materials in actual bonding processes.

[0139] The OCA film was heated to 10°C below its glass transition temperature (GTT). The stress relaxation time of each region was measured to generate the stress relaxation curve using a high-precision thermodynamic stress relaxation testing system. This system consists of a micro-strain loading device, a high-precision force sensor (resolution 0.01 mN), a precision temperature control system (temperature accuracy ±0.1°C), and a data acquisition system. The glass transition temperature (Tg) is the characteristic temperature at which a polymer material transitions from the glassy to the rubbery state and is a key parameter reflecting the mobility of the molecular chain. The stress relaxation time (τ), defined in seconds as the time required for the internal stress of the material to decrease to 1 / e (approximately 36.8%) of its initial value, directly reflects the motion characteristics and internal structure of the molecular chain. Prior to testing, the Tg value of the OCA film was determined by differential scanning calorimetry and is generally within the range of 70-85°C. The OCA film temperature was then precisely controlled within a range of 10°C minus Tg (i.e., 60-75°C). This temperature range was chosen based on the dynamic properties of polymer chain segments: at this temperature, the molecular chains have sufficient thermal mobility to exhibit stress relaxation behavior, while not completely releasing internal stress and orientation characteristics. During the test, an initial stress of 0.5 MPa was applied to each of the 100 selected test points. The deformation was then maintained constant, and the stress decay curve was recorded over time for one hour. The stress-time curve was fitted with an exponential decay function to extract the stress relaxation time, τ, for each test point. For a typical OCA film, τ values ​​in normal regions are approximately 500-1000 seconds, while τ values ​​in stress-abnormal regions can deviate significantly from this range: smaller τ values ​​(<500 seconds) in stress-concentrated regions indicate unstable molecular chain alignment, while larger τ values ​​(>1000 seconds) in highly oriented regions indicate highly ordered and stable molecular chain alignment. Stress relaxation testing reveals the dynamic response of a material under the combined effects of temperature and force, providing time-dependent information not available through conventional static testing. This is crucial for predicting the long-term stability of OCA films in practical applications.

[0140] According to the orientation order parameter rate of change and the stress relaxation curve, a stress-orientation coupling response function describing the relationship between molecular orientation and stress response is established, and a multi-parameter correlation analysis method is used for data processing. The stress-orientation coupling response function is a mathematical expression quantitatively describing the relationship between the orientation characteristics of molecular chains and the stress state, and can predict the stress distribution characteristics under a specific orientation structure. The function construction process first normalizes the orientation order parameter rate of change (dS / dσ) and the stress relaxation time (τ) of each test point to eliminate the dimensional difference. Then, the correlation coefficient matrix between the normalized parameters is calculated to identify the key influencing factors. Next, through multivariate regression analysis, the stress-orientation coupling response function F is established, which expresses the stress state σ as a function of the orientation parameter S, the orientation order parameter rate of change dS / dσ and the stress relaxation time τ: σ=F(S,dS / dσ,τ). For a typical OCA film, the function form is σ=a·S+b·(dS / dσ)+c·ln(τ)+d, where a, b, c, d are fitting coefficients, respectively reflecting the contribution weight of each parameter to the stress state. Through fitting the data of 100 test points, the optimal coefficient values are determined to minimize the root mean square error between the predicted stress and the measured stress (usually <0.1 MPa). This stress-orientation coupling response function not only quantitatively describes the relationship between the microstructure of molecules and the macroscopic mechanical properties, but also can predict the stress state of the untested area, providing an effective tool for comprehensive evaluation of the stress distribution of OCA film. Compared with the traditional single-parameter correlation analysis, this method considers the static structure characteristics and dynamic response characteristics of molecular chains, and can more accurately reflect the complex mechanical behavior of OCA film, especially in the nonlinear response region.

[0141] The stress-orientation coupling response function is analyzed in space position with the OCA film internal stress distribution map to obtain a molecular chain orientation-stress distribution mapping relationship, and high-precision space registration and data fusion technology is adopted. The molecular chain orientation-stress distribution mapping relationship refers to the quantitative corresponding relationship between the molecular chain orientation characteristics and the internal stress distribution state in the three-dimensional space of the OCA film, and directly displays the spatial correlation between the microstructure and the macro performance. In the implementation process, firstly, the molecular chain orientation data and the internal stress distribution data are converted to a unified reference coordinate system, and the accuracy is better than 1 μm. Then, the two groups of data are subjected to spatial interpolation to generate a high-density data grid (500*500 points) with consistent resolution. Then, at each grid point, the measured internal stress value is compared with the stress value predicted based on the stress-orientation coupling response function, and the relative error is calculated. For a typical OCA film, the relative error of more than 90% of the area is less than 10%, which verifies the effectiveness of the coupling response function. Finally, a complete molecular chain orientation-stress distribution mapping diagram is constructed, which contains multiple layers of information: the bottom layer is the spatial profile of the OCA film, the middle layer is the color-coded internal stress distribution, and the top layer is the vector-represented molecular chain orientation distribution, which directly displays the spatial corresponding relationship between the two. This mapping relationship reveals important material behavior rules: for example, in the region where the molecular chain is highly oriented and the direction is consistent, the internal stress distribution is uniform; in the boundary region where the molecular chain orientation changes abruptly, stress concentration points are easily formed; in the region where the molecular chain orientation is chaotic, the internal stress distribution presents irregular fluctuations. Through this mapping analysis, not only the accuracy of the aforementioned stress-orientation coupling response function is verified, but also the internal relationship between the microstructure and the mechanical properties of the OCA film is revealed in depth, which provides a scientific basis for optimizing the material structure and improving the bonding process.

[0142] Please continue to refer to Figure 1 According to the molecular chain orientation-stress distribution mapping relationship, a directional electric field is applied to rearrange the molecular chain arrangement of the OCA film, the stress change in the molecular chain rearrangement process is measured, and stress reconstruction data is obtained.

[0143] In an embodiment of the present application, the stress reconstruction data obtained by applying a directional electric field to rearrange the molecular chain arrangement of the OCA film according to the molecular chain orientation-stress distribution mapping relationship and measuring the stress change in the molecular chain rearrangement process comprises:

[0144] From the molecular chain orientation-stress distribution mapping relationship, the shear stress abnormal area and the molecular chain arrangement direction corresponding to the identified shear stress abnormal area are identified, an initial electric field with a 45° angle with the molecular chain arrangement direction is applied to each stress abnormal area, and the initial displacement angle of the molecular chain is measured and recorded.

[0145] According to the initial displacement angle of the molecular chain, the angle between the electric field direction and the new orientation direction of the molecular chain is adjusted to 90°, and the temperature of the OCA film is adjusted to 10°C below the glass transition temperature, and the spatial orientation change data of the molecular chain is recorded;

[0146] Based on the spatial orientation change data of the molecular chain, the regions of the molecular chain that need to be further adjusted are identified and determined, and a reverse electric field is applied to the regions of the molecular chain that have undergone spatial orientation changes after the initial electric field action, so that the molecular chain produces reciprocating swing rearrangement, and the stress release time sequence in the swing process is recorded;

[0147] According to the stress release time sequence, the swing period at the minimum stress is determined, the molecular chain is fixed in the minimum stress swing period state, and stress reconstruction data is obtained.

[0148] The following describes the steps involved in the above embodiments:

[0149] The initial displacement angle of the molecular chain is defined as the initial change angle of the orientation direction of the molecular chain after the electric field is applied, which directly reflects the response sensitivity of the molecular chain to the electric field. When the electric field is applied, the angle of 45° with the molecular chain arrangement direction is the best angle determined based on the theory of polymer electro-mechanical response, at which the moment effect of the electric field is the largest, and significant molecular chain rearrangement can be caused by the smallest electric field strength (usually 1-3 kV / cm). Experiments show that regions with different stress states exhibit different initial displacement angles of the molecular chain: normal stress regions are about 3-5°, and high stress regions can reach 10-15°. This difference provides an important basis for subsequent precise control.

[0150] Based on the initial displacement angle of the molecular chain, the angle between the electric field direction and the new orientation direction of the molecular chain is adjusted to 90°. At the same time, the temperature of the OCA film is adjusted to 10°C below the glass transition temperature. When recording the data on the spatial orientation change of the molecular chain, a closed-loop feedback electric field control system and a precision temperature control platform are used. The new orientation direction of the molecular chain refers to the latest direction of the molecular chain arrangement after the initial electric field is applied, which has a certain deviation from the original arrangement direction. The angle between the electric field direction and the new orientation direction of the molecular chain is adjusted to 90° in order to maximize the torque effect of the electric field on the molecular chain. According to the polymer electrical response theory, when the electric field direction is perpendicular to the axis of the molecular chain, the torsional torque generated reaches its maximum, which can effectively drive the molecular chain to further rearrange and achieve precise control of the molecular arrangement. The adjustment process adopts a real-time closed-loop control strategy: the current orientation direction of the molecular chain is measured every 100ms, and then the electric field direction is immediately adjusted to keep it at a 90° angle with the most recently measured molecular chain direction. Simultaneously, a temperature control system heats the OCA film to 10°C below its glass transition temperature (Tg). For typical OCA materials, Tg is approximately 70-85°C, so the operating temperature is controlled within the 60-75°C range. This temperature range is determined based on the motion characteristics of the polymer chain segments: below this temperature, the molecular chains are insufficiently mobile and difficult to respond to the electric field; above this temperature, the thermal motion of the molecular chains is excessive, disrupting the original orientation structure and stress distribution. Under these conditions, the electric field is applied continuously for 30 minutes, and data on the spatial orientation changes of the molecular chains across the entire field of view are recorded every minute. This data includes information such as the change in orientation angle, orientation uniformity, and local orientation order parameters.

[0151] Based on the molecular chain spatial orientation change data, regions of the molecular chain requiring further adjustment are identified and determined. A reverse electric field is applied to regions where the molecular chain spatial orientation changes after the initial electric field, causing the molecular chain to oscillate back and forth and rearrange. A spatially selective electric field control system is used to record the stress release time series during the oscillation process. Regions of the molecular chain requiring further adjustment are those where the molecular chain orientation remains suboptimal or the stress state remains abnormal after the initial electric field treatment. This identification process is achieved by analyzing the non-uniformity and instability characteristics of the molecular chain spatial orientation change data. Specifically, the spatial standard deviation and temporal rate of change of the orientation change are calculated, and regions above a threshold are marked as requiring further adjustment. The reverse electric field is an electric field with a direction opposite to that of the previous electric field, which is used to generate a reverse torque to cause the molecular chain to oscillate in the opposite direction. The frequency of the reverse electric field application is initially set to 1 Hz, meaning that the direction of the electric field changes once per second, causing the molecular chain to oscillate back and forth in a regular pattern. The stress release time series is a data sequence that records the time-varying stress changes within a region during the molecular chain oscillation process, directly reflecting the regulatory effect of molecular rearrangement on the internal stress of the material. A real-time photoelastic stress measurement system was used to continuously record stress changes at a frequency of 10 Hz, obtaining a complete stress release time series. For typical stress anomaly regions, after applying a reverse electric field, the stress values ​​exhibited an oscillatory attenuation trend: initially, the stress fluctuated significantly (±0.3 MPa). As the molecular chains gradually found their lowest-energy arrangement, the fluctuations gradually decreased, eventually settling to a stable value, typically 40-60% lower than the initial stress.

[0152] The oscillation period at which stress is minimized is determined based on the stress release time series. The molecular chain is fixed in this state of minimum stress oscillation period. When obtaining stress reconstruction data, an optimization control algorithm and rapid cooling and solidification techniques are applied. The minimum stress oscillation period is the electric field reversal period (measured in seconds or Hertz) that minimizes the average stress in the region during the reciprocating oscillation of the molecular chain. The determination process first performs a Fourier transform on the stress release time series to identify the dominant frequency component of the stress fluctuations. Then, a fine scan is performed near this dominant frequency in 0.1 Hz steps to find the precise frequency value that minimizes the average stress, i.e., the optimal oscillation period. For typical OCA films, the optimal oscillation period is typically in the range of 0.5-2 Hz, reflecting the intrinsic relaxation characteristics of the molecular chain at a specific temperature. After determining the optimal oscillation period, the electric field frequency is precisely adjusted to this value and maintained at this state for 10 minutes to allow the molecular chain to fully adapt to this oscillation rhythm. Subsequently, while maintaining the electric field, the OCA film temperature is rapidly cooled to room temperature (25°C) at a controlled cooling rate of 10°C / minute, "freezing" the rearranged molecular chain structure in the minimum stress state. After cooling is complete, the electric field is turned off, and the material is allowed to fully stabilize for 10 minutes before comprehensive stress distribution measurements are performed to obtain stress reconstruction data. Compared to the initial stress distribution, the reconstructed stress distribution shows significant improvement: peak stress is reduced by 50-70%, stress gradient is reduced by 60-80%, and overall stress distribution uniformity is improved by 2-3 times. This electric field-assisted molecular chain rearrangement technology not only effectively reduces shear stress anomalies in the OCA film, but also creates a more uniform and stable molecular arrangement structure, significantly improving the performance and reliability of the material during the bonding process.

[0153] In one embodiment of the present invention, applying a reverse electric field to the region where the molecular chains undergo spatial orientation changes after the initial electric field, causing the molecular chains to oscillate back and forth and rearrange, and recording a stress release time series during the oscillation process, comprises:

[0154] A high-speed photoelastic phase microscopy system capable of real-time detection of material stress states was used to continuously collect molecular chain swing data at a sampling rate of 1000 frames per second.

[0155] Calculating an optimal resonance frequency according to the molecular chain swing data, and adjusting the reverse electric field frequency to the calculated optimal resonance frequency;

[0156] Temperature cycle adjustment is performed within the range of glass transition temperature ±5℃ to maintain the activity of molecular chain movement;

[0157] The molecular chain motion process under the action of resonant electric field and temperature cycle is collected, and the stress release time series during the swing process is recorded.

[0158] The following is a detailed description of the steps involved in the above embodiment:

[0159] A high-speed photoelastic phase microscopy system, capable of real-time monitoring of material stress states, continuously acquired molecular chain oscillation data at a sampling rate of 1000 frames per second using a composite optical detection platform. This system is an optical measurement device capable of observing changes in stress distribution within a material in real time. It combines photoelastic principles with phase-sensitive technology to capture ultrafast stress changes. The system consists of a high-speed polarized light source (550nm wavelength), a stress-induced birefringence detector, a phase compensator, and a high-frame-rate camera (1920×1080 pixel resolution). Molecular chain oscillation data refers to the sequence of optical signal changes generated by the periodic rotation of molecular chains in the OCA film under the influence of an electric field, directly reflecting the dynamic process of molecular structural rearrangement. During measurement, the OCA film is placed between transparent electrodes (indium tin oxide-coated glass), an alternating electric field is applied, and polarized light is irradiated from a perpendicular direction. As the molecular chains oscillate under the influence of the electric field, the optical anisotropy of the material changes, resulting in periodic changes in the polarization state of the transmitted light. These changes are converted into digital signals by the phase detector. The sampling rate of 1000 frames per second is based on the response characteristics of the molecular chains in the OCA material: the typical electric field response time of a molecular chain is 1-10 milliseconds. To accurately capture its dynamic characteristics, a sampling frequency at least 10 times the highest response frequency is required, hence the choice of 1000Hz. In actual testing, the system was able to simultaneously track the dynamic behavior of the molecular chain at approximately 100 × 100 spatial points within a 10mm × 10mm OCA film area, forming a complete, spatiotemporally resolved oscillation dataset. This precisely records the molecular chain's oscillation amplitude (typically 5-15°), phase difference, and attenuation characteristics, providing a key basis for subsequent optimization.

[0160] The optimal resonant frequency is calculated according to the molecular chain swing data, and when the reverse electric field frequency is adjusted to the calculated optimal resonant frequency, the resonance characteristic analysis method is used to process the data. The optimal resonant frequency refers to the electric field alternating frequency that causes the molecular chain in the OCA film to produce the maximum response amplitude. At this frequency, the energy absorption efficiency of the molecular chain is the highest and the rearrangement effect is the best. The calculation process first performs a time domain decomposition on the molecular chain swing data of each spatial point to extract the amplitude and phase information. The response intensity of the molecular chain to electric fields of different frequencies is then tested by the sweep frequency analysis method. In the specific operation, an electric field sequence with a frequency ranging from 0.1 Hz to 10 Hz and a step size of 0.1 Hz is applied to the OCA film. Each frequency lasts for 60 seconds, and the response amplitude of the molecular chain is recorded. For a typical OCA film, the response amplitude-frequency curve shows an obvious peak feature, and the frequency corresponding to the peak is the resonant frequency of the area. Due to differences in molecular chain alignment and internal stress states, the resonant frequencies of different OCA film regions vary, typically within a range of 0.5-5 Hz: highly oriented regions have lower resonant frequencies (0.5-1 Hz), while regions with more complex orientation have higher resonant frequencies (3-5 Hz). After determining the resonant frequencies of each region, a numerically controlled electric field generator precisely adjusts the reverse electric field frequency to the corresponding value, with an error within ±0.01 Hz. This resonant frequency electric field effect produces maximum molecular rearrangement with minimal energy input, significantly improving the efficiency and precision of stress control while effectively avoiding the risk of material damage caused by excessive electric field strength.

[0161] A precision temperature control system is used to maintain molecular chain mobility by cycling the temperature within ±5°C of the glass transition temperature. The glass transition temperature (Tg) is the characteristic temperature at which a polymer material transitions from a rigid glassy state to a soft, rubbery state. The Tg of OCA materials is typically between 70-85°C. Temperature cycling involves increasing and decreasing the material temperature within a set temperature range in a specific pattern. The goal is to provide the appropriate amount of thermal energy to activate the molecular chains while avoiding structural disruption caused by excessive temperatures. The Tg of the OCA film is first accurately determined using differential scanning calorimetry. A temperature cycling protocol is then designed: heating from Tg - 5°C to Tg + 5°C at a rate of 2°C / minute, holding for 10 minutes; then cooling to Tg - 5°C at the same rate, holding for 10 minutes; and repeating this cycle three times. The Tg ± 5°C temperature range is precisely calculated to be the optimal range: within this temperature range, the OCA material is in the glassy-rubbery transition zone, exhibiting moderate molecular chain mobility, allowing for rearrangement under the influence of an electric field without completely disrupting the original molecular orientation. Compared to constant temperature treatment, temperature cycling provides periodic thermal activation energy, allowing even deeply "frozen" molecular segments to participate in the rearrangement process, achieving more uniform and in-depth structural adjustments. Experiments have shown that under the same electric field conditions, temperature cycling can increase the depth of molecular rearrangement by 40-60% compared to constant temperature treatment, significantly improving the uniformity and stability of stress regulation.

[0162] A multi-parameter synchronous acquisition system was used to collect and process data from the molecular chain motion under the influence of a resonant electric field and temperature cycling, recording the stress release time series during the swinging process. A resonant electric field is an alternating electric field with a frequency equal to the material's resonant frequency, which induces the strongest molecular chain rearrangement response. The stress release time series describes the temporal evolution of the material's internal stress, directly reflecting the effect of molecular rearrangement on the stress state. During the acquisition process, a high-precision stress sensor array (sensitivity 0.01 MPa) was used to monitor the stress state in various regions of the OCA film in real time. A sampling frequency of 200 Hz ensured that the fastest stress changes could be captured. Simultaneously, a polarized light microscope was used to record the spatial orientation changes of the molecular chains. The time synchronization error between the two systems was kept within 0.5 milliseconds. At each time point during each temperature cycle, the temperature value T(t), electric field intensity E(t), molecular chain orientation angle θ(t), and stress value σ(t) were recorded to form a complete multi-parameter time series. Data analysis shows that under the combined effects of a resonant electric field and temperature cycling, the stress release process of the OCA film exhibits distinct phased characteristics: an initial rapid release phase (0-10 minutes), with a rapid decrease of 30-40%; a mid-stage slow release phase (10-40 minutes), with a further decrease of 15-25%; and a late stabilization phase (>40 minutes), with a stable stress value and fluctuations of less than 5%. This complete stress release time series not only records the final stress control effect but also reveals the kinetics of stress release, providing a scientific basis for optimizing treatment processes and predicting long-term material performance. Compared to traditional static measurements, this dynamic monitoring method can capture both the transient characteristics and cumulative effects of the material response, providing a more comprehensive assessment of the effects of resonant electric field and temperature cycling on the microstructure of the OCA film.

[0163] Please continue reading Figure 1 , using the stress reconstruction data to determine the bonding parameters between the OCA film and the glass substrate, and executing the bonding process between the OCA film and the glass substrate.

[0164] In one embodiment of the present invention, determining the bonding parameters between the OCA film and the glass substrate using the stress reconstruction data and performing the bonding process between the OCA film and the glass substrate includes:

[0165] Converting the stress reconstruction data into a stress gradient distribution map, and determining the optimal initial contact point position of the OCA film according to the direction of the minimum stress gradient;

[0166] Starting from the optimal initial contact point, the law of stress propagation in the material is analyzed, the propagation direction of stress during the bonding process is calculated, and the surface of the OCA film is divided into stress gradient control areas;

[0167] Performing a polarity gradient treatment on the surface of the glass substrate that can generate a surface energy difference, thereby constructing a surface energy distribution field that matches the stress gradient control area;

[0168] According to the surface energy distribution field, a stress gradient attenuation channel is designed to determine the stress release path during the bonding process;

[0169] According to the stress release path, a progressive pressure control strategy is adopted to form directional stress release in each stress gradient control area;

[0170] According to the propagation feedback of the directional stress release, the lamination pressure and speed are dynamically adjusted to complete the lamination process of the OCA film and the glass substrate.

[0171] The following is a detailed description of the steps involved in the above embodiment:

[0172] The stress reconstruction data is converted into a stress gradient distribution diagram. When the optimal initial contact point position of the OCA film is determined according to the direction of the minimum stress gradient, a spatial gradient analysis system is used for data processing. The stress gradient distribution diagram is an image representation of the spatial change rate of stress, which intuitively shows the trend and rate of change of stress in the material. The processing process first imports the stress reconstruction data into a dedicated analysis software to construct a high-resolution three-dimensional stress matrix (resolution 0.1mm×0.1mm×0.01mm). Then calculate the gradient vector of stress in space, that is, the partial derivative of the stress value in the three coordinate directions. For each spatial point (x, y, z), calculate the stress gradient vector , whose magnitude indicates the rate of stress change, and its direction points to the direction of the fastest stress increase. The stress gradient distribution diagram uses color coding (blue indicates low gradient, red indicates high gradient) to intuitively display the gradient distribution. The optimal initial contact point for the OCA film is defined as the center of the area with the lowest stress gradient on the film surface. Initiating bonding at this location ensures the most uniform stress distribution at the initial contact point, avoiding local deformation and bubbles caused by sudden stress changes. For a typical 100mm×100mm OCA film, after stress reconstruction, the stress gradient values ​​are typically distributed within the range of 0.01-0.5MPa / mm, with the minimum gradient area approximately 5mm×5mm, located at a specific location on the film (usually not at the geometric center). The area with the lowest stress gradient, rather than the lowest stress value, is selected as the initial contact point because the bonding process is essentially a dynamic stress propagation process. Areas with low gradients provide a smoother stress transition, ensuring the stable advancement of the bonding wavefront.

[0173] Starting from the optimal initial contact point, the stress propagation patterns in the material are analyzed, the stress propagation direction during the bonding process is calculated, and a mechanical propagation dynamics analysis method is applied to divide the OCA film surface into stress gradient control regions. The stress propagation direction during the bonding process refers to the preferred path along which the bonding contact line advances across the OCA film surface, along which bonding achieves the most uniform stress distribution. The analysis first establishes a mechanical model of the bonding process, taking into account the elastic properties (Young's modulus, Poisson's ratio) and interfacial properties (adhesion energy, contact angle) of the OCA film. Then, with the optimal initial contact point as the center, the stress propagation characteristics in all directions are calculated, including propagation velocity, decay rate, and stability. The propagation direction is selected based on the minimum energy principle, i.e., the path that minimizes the increase in the total energy of the system is chosen. Stress gradient control regions are regions on the OCA film surface with similar stress propagation characteristics and requiring the same bonding parameters. The OCA film surface is divided into 5-10 control regions based on the similarity of stress gradient magnitude and direction, with the stress gradient within each region varying by no more than 0.05 MPa / mm. For typical OCA films, the control areas are distributed radially or in concentric rings, extending outward from the initial contact point. This stress gradient-based area division method more accurately reflects the material's actual mechanical behavior than traditional geometric division methods, providing a precise basis for subsequent bonding parameter design. Experiments have shown that the bonding path determined using this method can reduce contact stress fluctuations by 50-70%, significantly reducing the rate of bubble formation during the bonding process.

[0174] Precision surface modification technology is used to create a polarity gradient treatment on the glass substrate surface that can produce surface energy differences and construct a surface energy distribution field that matches the stress gradient control area. Polarity gradient treatment refers to the use of physical or chemical methods to create areas of gradually changing polarity (hydrophilicity or hydrophobicity) on the substrate surface, thereby changing the interaction strength between the surface and the OCA film. The surface energy distribution field refers to the state in which different locations on the glass substrate surface have different surface energies, which directly affects the dynamic characteristics of the adhesion process. The treatment method first thoroughly cleans the glass substrate using an ultrasonic cleaning system combined with alternating isopropyl alcohol and deionized water to remove surface contaminants. Then, based on the aforementioned stress gradient control area map, the corresponding surface energy distribution pattern is designed. Plasma gradient treatment technology is used to implement surface modification. The plasma power (50-200W), treatment time (10-60 seconds) and gas composition (oxygen, argon, carbon tetrafluoride mixed gas, the proportions adjusted according to the target polarity) are controlled to create a surface energy distribution field on the glass surface ranging from 20mJ / m 2 to 72mJ / m 2Continuously changing areas. For areas of the OCA film with high stress gradients, corresponding glass areas with lower surface energy gradients are processed; for areas of the OCA film with low stress gradients, corresponding glass areas with higher surface energy gradients are processed. This inverse matching of surface energy and stress gradients rebalances stress during the bonding process, resulting in weaker adhesion in high-stress areas and stronger adhesion in low-stress areas, thus balancing the stress distribution at the contact interface overall. Compared to uniform surface treatment, this treatment method can improve stress uniformity at the bonding interface by 30-50%, making it particularly suitable for the OCA bonding process of large-size or curved display devices.

[0175] Based on the surface energy distribution field, stress gradient attenuation channels are designed to determine the stress release path during the lamination process. Fluid dynamics optimization algorithms are used for channel design. Stress gradient attenuation channels are specific paths that allow excess adhesive and gas to escape during the lamination process while gradually reducing the stress gradient. The stress release path is the actual trajectory of the contact line during lamination, determining the direction and speed of the stress wavefront. The design process first analyzes the gradient direction of the surface energy distribution field to identify the surface energy "ridges" and "valleys." These features directly influence the stability of the adhesion front. Next, the main stress release channel is designed to extend along areas of minimal surface energy gradient. The channel width is 1-3 mm, forming a tree-like branching structure. For a 100 mm × 100 mm OCA film, a typical design includes one main channel and three to five branch channels, covering the entire lamination area. The channel curvature radius is kept within the range of 5-20 mm to avoid stress concentration caused by sharp turns. The design concept of this stress release channel is similar to that of a natural river system: the main channel carries the primary material and energy transport, while the branch channels ensure coverage of all areas requiring stress release. Compared with traditional straight or spiral bonding paths, this release path based on the coordinated design of stress field and surface energy field can achieve a smoother bonding process and reduce the bubble residual rate by 60-80%. It is particularly suitable for OCA bonding of display devices with extremely high optical quality requirements.

[0176] According to the stress release path, a progressive pressure control strategy is adopted, and a precise force feedback conforming system is used when forming directional stress release in each stress gradient control area. The progressive pressure control strategy refers to a method of dynamically adjusting the size, application rate and spatial distribution of pressure according to the material response characteristics in the conforming process. Directional stress release refers to orderly discharging stress along the preset path to avoid stress fluctuations and bubble generation caused by random release. The implementation process first designs the pressure profile of each control area, including the initial pressure (0.05-0.2 MPa), the pressure growth rate (0.01-0.05 MPa / s) and the maximum pressure (0.3-0.8 MPa). Then, a multi-point independent control pressure application system is used to gradually advance the conforming front according to the order of the stress release path, starting from the optimal initial contact point. Key parameters include pressure front advance speed (1-5 mm / s) and pressure gradient (0.05-0.2 MPa / mm), which are accurately set according to the stress state and viscoelastic properties of the OCA film. For high stress gradient areas, lower pressure and slower advance speed are used; for low stress gradient areas, higher pressure and faster advance speed can be used. This differentiated pressure control strategy can adapt to the differences in material properties of different areas of the OCA film, ensuring that each area obtains the most suitable conforming conditions. Experiments have shown that compared with the uniform pressure conforming method, the progressive pressure control can reduce 40-60% of the conforming defects, and the conforming effect of large-size display panels (>55 inches) and curved display devices is more significantly improved.

[0177] Based on the propagation feedback of the directional stress release, the lamination pressure and speed are dynamically adjusted to complete the lamination process between the OCA film and the glass substrate. A real-time monitoring and adaptive control system is employed during the lamination process. Propagation feedback of the directional stress release refers to the real-time acquisition of stress distribution changes and contact line advancement status information by sensors during the lamination process. Dynamic adjustment refers to the process of modifying lamination parameters in real time based on this feedback to optimize the lamination results. During implementation, a high-precision optical monitoring system (including a polarization interferometer and a high-speed camera) observes the lamination process in real time, collecting key metrics including contact line shape (straightness deviation <0.1mm), advancement speed uniformity (fluctuation <10%), and contact area stress distribution (uniformity >85%). Data acquisition is performed at a 50Hz frequency to ensure the capture of the fastest dynamic changes. Based on this monitoring data, an adaptive control algorithm calculates the optimal lamination parameters in real time, adjusting the pressure change rate (±0.02MPa / s), contact line advancement speed (±1mm / s), and pressure distribution pattern. For example, if the system detects excessive advancement speed in a certain section of the contact line, it automatically reduces pressure in that area. If uneven stress distribution is detected, the pressure gradient is adjusted to balance the stress distribution. The entire bonding process lasts 100-300 seconds (depending on the size of the OCA film), during which the system fine-tunes parameters 200-600 times to ensure optimal bonding. This dynamic control method, based on real-time feedback, overcomes the limitations of traditional bonding based on preset parameters, capable of addressing fluctuations in material properties and environmental changes, increasing bonding yield to over 98%, significantly reducing operator skill dependency, and achieving consistently reproducible, high-quality bonding processes.

[0178] In one embodiment of the present invention, designing a stress gradient attenuation channel based on the surface energy distribution field and determining a stress release path during the bonding process includes:

[0179] According to the gradient direction of the surface energy distribution field, the stress release channel is divided into a first stress release channel that performs a main stress release function and a second stress release channel that performs an auxiliary stress release function;

[0180] Calculating the geometric characteristics of the first stress release channel, including the curvature radius and the extension direction, and constructing a main stress release path;

[0181] Designing a branch position and an attenuation gradient of the second stress release channel according to the direction of the main stress release path, wherein the branch position determines the connection point between the second stress release channel and the first stress release channel, and the attenuation gradient determines the degree of stress reduction in the second stress release channel;

[0182] The first stress release channel and the second stress release channel are connected according to the branch position and the attenuation gradient to form a stress gradient attenuation network, thereby determining a stress release path during the bonding process.

[0183] The following is a detailed description of the steps involved in the above embodiment:

[0184] When dividing the stress release channel into a first stress release channel that undertakes the main stress release function and a second stress release channel that undertakes the auxiliary stress release function according to the gradient direction of the surface energy distribution field, a gradient domain analysis system is used for channel planning. The gradient direction of the surface energy distribution field refers to the direction in which the surface energy changes fastest in space, which is represented by a vector and directly affects the movement trend of the adhesion front. The first stress release channel refers to the main channel that undertakes the main stress and material (gas, excess glue) discharge function during the bonding process, and usually has a larger channel width and higher stress conduction ability; the second stress release channel refers to the auxiliary channel connected to the main channel and responsible for stress release in the local area, and usually has a smaller channel width and a special area coverage function. The division process first calculates the gradient vector of each point in the surface energy distribution field. , including gradient size and direction. Then, based on the topological characteristics of the gradient field, the gradient convergence line and gradient divergence line are identified. These lines correspond to the stress accumulation path and release path respectively. For a typical 100mm×100mm glass substrate, the surface energy gradient of 300×300 grid points is accurately calculated to form a complete gradient field map. The classification standard is: the gradient size exceeds 3mJ / m 2 Gradient convergence lines with a length of 1.0 mm and a continuous length exceeding 20 mm are designated as the primary stress release channel; remaining shorter convergence lines or those with smaller gradients are designated as secondary stress release channels. This surface energy gradient-based channel division method fully utilizes the physical properties of the material surface, allowing stress release to follow a "natural path" and significantly reducing internal resistance and unevenness during the bonding process. Experiments have shown that compared to traditional geometrically uniform division methods, this gradient-guided channel division can improve stress release efficiency by 30-50%, making it particularly suitable for bonding large-scale OCA films with complex internal stress distributions.

[0185] The geometric characteristics of the first stress release channel, including the curvature radius and extension direction, are calculated. When constructing the main stress release path, geometric parameterized analysis methods are applied for feature extraction and path planning. The curvature radius is a parameter that describes the degree of curvature of the channel. The smaller the value, the sharper the curvature. The extension direction is the tangent direction of the channel at each point and determines the forward path of stress propagation. The calculation process first discretizes the sampling of the first stress release channel, taking a sampling point every 1mm along the centerline of the channel to obtain the coordinate data of 200-300 feature points. Then, the local curvature radius r is calculated for every three consecutive points using the circle fitting method, and the direction angle θ of the line connecting the adjacent points is calculated as the local extension direction. For the bonding process, the curvature radius of the first stress release channel is limited to the range of 5-50mm. This is because when the curvature radius is less than 5mm, it is easy to cause stress mutation and bubble accumulation, and when it is greater than 50mm, it is difficult to adapt to complex stress distribution changes. The rate of change in the extension direction is controlled to no more than 5° per millimeter to ensure a smooth transition of the channel. Based on these local geometric properties, a Bezier curve fitting algorithm is used to generate a continuous and smooth main stress release path. This path, while satisfying geometric constraints, adheres to the "natural path" guided by the surface energy gradient to the greatest extent possible. This precisely calculated main stress release path, compared to simple straight or circular paths, can more accurately adapt to the inherent stress characteristics and surface energy distribution characteristics of the material, providing an optimal stress release main channel for subsequent bonding processes.

[0186] Based on the orientation of the primary stress release path, the branch locations and attenuation gradients of the secondary stress release channel are designed. The branch locations determine the connection points between the secondary stress release channel and the primary stress release channel, and the attenuation gradient determines the degree of stress reduction in the secondary stress release channel. A hierarchical stress distribution algorithm is used to optimize the channels. The branch locations are the intersections of the secondary and primary stress release channels, corresponding to the nodes where stress converges from the secondary region to the primary channel during lamination. The attenuation gradient refers to the rate at which stress decreases in the secondary stress release channel, typically expressed as stress reduction per unit length in MPa / mm. The design process begins by identifying suitable locations for branching along the primary stress release path. Ideally, these locations should be areas with minimal curvature variation and sufficient stress conduction capacity. For a 100mm×100mm OCA film, 6-10 branch locations are typically selected along the primary path, with spacing of 10-20mm. Secondary stress release channels are then extended from each branch location toward the surrounding high-stress areas. The channel width is 0.5-2mm, and the length is determined based on coverage requirements, typically 5-30mm. The key parameter is the attenuation gradient of the second stress release channel, designed to be 0.02-0.1 MPa / mm. This range is determined based on the stress conduction limit of the OCA material and its elastic stability after curing. Too low an attenuation gradient will result in excessively long stress transmission distances, affecting local bonding quality; too high an attenuation gradient can lead to sudden stress changes and bubble formation. In practical applications, a lower attenuation gradient (approximately 0.02-0.05 MPa / mm) is set for areas with higher stress to ensure sufficient stress release; a higher attenuation gradient (approximately 0.05-0.1 MPa / mm) is set for areas with moderate stress to improve release efficiency.

[0187] Based on the branch locations and the attenuation gradient, the first and second stress relief channels are connected to form a stress gradient attenuation network. When determining the stress relief paths during the bonding process, network topology optimization methods are applied to complete channel system integration. A stress gradient attenuation network is a spatial network structure formed by the interconnected first and second stress relief channels, characterized by a gradual attenuation of stress from high to low, similar to the main trunk and tributaries of a river. The stress relief path refers to the actual trajectory of the contact front during the bonding process, which determines the direction and efficiency of gas and excess adhesive discharge. The connection process first ensures a smooth physical transition between the channels, using circular arc connections (radius 3-5mm) at each branch location to avoid sudden stress changes. Next, all possible stress propagation paths in the network are calculated, with dozens of potential paths from the starting point (initial contact point) to the end point (each edge point). The cumulative stress attenuation value is calculated for each path, and the path with the smoothest and most uniform attenuation is selected as the progression order during the actual bonding process. For a typical OCA bonding process, the total length of the stress relief path is 100-300mm, covering the entire bonding area, forming a tree-like or river-like structure. The key principle of path planning is "from near to far, from simple to complex": first complete the bonding of the main channel, then gradually expand to the branch areas, ensuring that air and excess colloid always have unobstructed exhaust channels. Compared with simple linear or spiral paths, this network-based stress release path can more comprehensively adapt to the stress distribution characteristics of complex OCA films and is particularly suitable for high-precision bonding of large-sized and special-shaped display panels. Practical applications have shown that using this stress gradient attenuation network for bonding reduces bubble rate by 70-90% and improves bonding uniformity by 40-60%, significantly improving the optical performance and service life of high-end display devices.

[0188] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for bonding glass with OCA optical adhesive, characterized in that: include: By introducing fluorescent marker molecules into the OCA film, irradiating the OCA film with polarized light of different polarization directions, and measuring the fluorescence intensity distribution, the spatial distribution map of the molecular chain orientation of the OCA film is obtained; applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing a corresponding relationship between the swelling rate and the internal stress, and obtaining an internal stress distribution map of the OCA film; Performing a correlation analysis on the spatial distribution map of the molecular chain orientation of the OCA film and the stress distribution map within the OCA film to obtain a molecular chain orientation-stress distribution mapping relationship; According to the molecular chain orientation-stress distribution mapping relationship, a directional electric field is applied to reconstruct the molecular chain arrangement of the OCA film, and the stress change during the molecular chain rearrangement process is measured to obtain stress reconstruction data; The stress reconstruction data is used to determine the bonding parameters between the OCA film and the glass substrate, and the bonding process between the OCA film and the glass substrate is performed.

2. The glass bonding method using OCA optical adhesive according to claim 1, characterized in that: The method introduces fluorescent marker molecules into the OCA film, irradiates the OCA film with polarized light of different polarization directions, and measures the fluorescence intensity distribution to obtain a spatial distribution map of the molecular chain orientation of the OCA film, including: introducing argon gas containing a naphthalene diimide derivative into a sealed cavity, placing an OCA film in the sealed cavity, and allowing the naphthalene diimide derivative to bind to the OCA film molecular chain through non-covalent interaction; performing vacuum treatment on the OCA film to remove unbound naphthalene diimide derivatives; Applying polarized light to the OCA film, rotating the polarized light direction at 5° intervals, and collecting fluorescence intensity data at each angle; Calculate the fluorescence anisotropy value according to the fluorescence intensity data at each angle to determine the spatial orientation angle of the OCA film molecular chain; Performing spatial coordinate mapping on the spatial orientation angles of the OCA film molecular chains to generate a spatial distribution map of the OCA film molecular chain orientations; After all measurements were completed, the OCA film was treated at 50°C for at least 30 minutes to completely volatilize the naphthalene diimide derivative and restore the original properties of the OCA film.

3. The glass bonding method using OCA optical adhesive according to claim 2, characterized in that: Applying polarized light to the OCA film, rotating the polarized light direction at 5° intervals, and collecting fluorescence intensity data at each angle include: A dual-wavelength polarized light system with a central wavelength of 350nm excitation light and 550nm emission light was used to synchronously illuminate the OCA film, and the dual-wavelength fluorescence intensity raw data at each rotation angle was recorded; Calculating the fluorescence signals at different depths based on the dual-wavelength fluorescence intensity raw data, and constructing the fluorescence intensity attenuation function at different depths of the OCA film; Reconstructing data in the depth direction using the fluorescence intensity attenuation function to obtain a fluorescence intensity distribution map for each depth layer; The fluorescence intensity distribution diagrams of each depth layer are superimposed to obtain fluorescence intensity data at each angle.

4. The glass bonding method using OCA optical adhesive according to claim 1, characterized in that: The step of applying mixed solvent vapor to the OCA film, measuring the local swelling rate, establishing a corresponding relationship between the swelling rate and the internal stress, and obtaining an internal stress distribution diagram of the OCA film comprises: Prepare a mixed solvent of tetrahydrofuran and isopropanol in a ratio of 3:7, and adjust the vapor concentration of the mixed solvent to 15% of the saturated vapor pressure at 25°C; exposing the OCA film to the mixed solvent vapor, and recording thickness variation data of the OCA film in different regions; Calculating the swelling rate of each region based on the thickness change data, and recording a curve of the swelling rate changing over time; Fitting the curve of the swelling rate versus time using an exponential decay model to calculate the characteristic swelling time that characterizes the swelling kinetics of each region; The surface stress distribution curve of the OCA film was drawn using the pre-established linear relationship between the characteristic swelling time and the internal stress. Based on the stress distribution curve of the OCA film surface, a complete stress distribution map of the OCA film is generated through calculation and processing; After the measurement and calculation are completed, the sample is placed in a vacuum environment at 50°C for at least 30 minutes to completely evaporate the solvent.

5. The glass bonding method using OCA optical adhesive according to claim 4, characterized in that: Exposing the OCA film to the mixed solvent vapor and recording thickness variation data of the OCA film in different regions includes: In a closed room, a mixed solvent vapor concentration gradient field is established, which decreases from the central value of 15% to 10% and increases to 20% outward; Short pulses of solvent vapor were applied to the OCA film surface at 100ms intervals, and regional thickness data before and after the pulses were collected. Arranging the regional thickness data in time series to obtain a dynamic thickness change curve; The thickness variation of each region is calculated according to the dynamic thickness variation curve, and the thickness variation data of the OCA film in different regions are recorded.

6. The glass bonding method using OCA optical adhesive according to claim 1, characterized in that: The performing correlation analysis on the molecular chain orientation spatial distribution diagram of the OCA film and the stress distribution diagram within the OCA film to obtain a molecular chain orientation-stress distribution mapping relationship includes: Applying a micro-area tensile load of 0.1-1.0 MPa to each region in the spatial distribution map of the molecular chain orientation of the OCA film, and recording the change in the orientation angle during the molecular chain rearrangement process; Calculating the change rate of the orientation order parameter characterizing the order of the molecular chain according to the change in the orientation angle to obtain orientation order parameter distribution data; The OCA film is heated to a temperature 10° C. lower than the glass transition temperature of the OCA film, and the stress relaxation time of each region is measured to obtain a stress relaxation curve. Establishing a stress-orientation coupling response function that describes the relationship between molecular orientation and stress response according to the orientation order parameter change rate and the stress relaxation curve; The stress-orientation coupling response function is analyzed in spatial correspondence with the stress distribution map in the OCA film to obtain a mapping relationship between molecular chain orientation and stress distribution.

7. The glass bonding method using OCA optical adhesive according to claim 1, characterized in that: The method of applying a directional electric field to reconstruct the molecular chain arrangement of the OCA film according to the molecular chain orientation-stress distribution mapping relationship, measuring the stress change during the molecular chain rearrangement process, and obtaining stress reconstruction data includes: Identifying shear stress abnormal regions and molecular chain arrangement directions corresponding to the identified shear stress abnormal regions from the molecular chain orientation-stress distribution mapping relationship, applying an initial electric field at an angle of 45° to the molecular chain arrangement direction to each stress abnormal region, and measuring and recording the initial displacement angle of the molecular chain; According to the initial displacement angle of the molecular chain, the angle between the electric field direction and the new orientation direction of the molecular chain is adjusted to 90°, and at the same time, the temperature of the OCA film is adjusted to 10°C below the glass transition temperature, and the data of the spatial orientation change of the molecular chain is recorded; Based on the molecular chain spatial orientation change data, identifying and determining the molecular chain region that needs further adjustment, applying a reverse electric field to the region where the molecular chain spatial orientation changes after the initial electric field, causing the molecular chain to oscillate back and forth and rearrange, and recording the stress release time series during the oscillation process; The oscillation period when the stress is minimum is determined according to the stress release time series, and the molecular chain is fixed in the state of the minimum stress oscillation period to obtain stress reconstruction data.

8. The glass bonding method using OCA optical adhesive according to claim 7, characterized in that: The method of applying a reverse electric field to the region where the molecular chain undergoes spatial orientation change after the initial electric field, causing the molecular chain to swing back and forth and rearrange, and recording the stress release time series during the swinging process, comprises: A high-speed photoelastic phase microscopy system capable of real-time detection of material stress states was used to continuously collect molecular chain swing data at a sampling rate of 1000 frames per second. Calculating an optimal resonance frequency according to the molecular chain swing data, and adjusting the reverse electric field frequency to the calculated optimal resonance frequency; Temperature cycle adjustment is performed within the range of glass transition temperature ±5℃ to maintain the activity of molecular chain movement; The molecular chain motion process under the action of resonant electric field and temperature cycle is collected, and the stress release time series during the swing process is recorded.

9. The glass bonding method using OCA optical adhesive according to claim 1, characterized in that: The method of determining the lamination parameters between the OCA film and the glass substrate by using the stress reconstruction data and executing the lamination process between the OCA film and the glass substrate includes: Converting the stress reconstruction data into a stress gradient distribution map, and determining the optimal initial contact point position of the OCA film according to the direction of the minimum stress gradient; Starting from the optimal initial contact point, the law of stress propagation in the material is analyzed, the propagation direction of stress during the bonding process is calculated, and the surface of the OCA film is divided into stress gradient control areas; Performing a polarity gradient treatment on the surface of the glass substrate that can generate a surface energy difference, thereby constructing a surface energy distribution field that matches the stress gradient control area; According to the surface energy distribution field, a stress gradient attenuation channel is designed to determine the stress release path during the bonding process; According to the stress release path, a progressive pressure control strategy is adopted to form directional stress release in each stress gradient control area; According to the propagation feedback of the directional stress release, the lamination pressure and speed are dynamically adjusted to complete the lamination process of the OCA film and the glass substrate.

10. The glass bonding method using OCA optical adhesive according to claim 9, characterized in that: The step of designing a stress gradient attenuation channel based on the surface energy distribution field and determining a stress release path during the bonding process includes: According to the gradient direction of the surface energy distribution field, the stress release channel is divided into a first stress release channel that performs a main stress release function and a second stress release channel that performs an auxiliary stress release function; Calculating the geometric characteristics of the first stress release channel, including the curvature radius and the extension direction, and constructing a main stress release path; Designing a branch position and an attenuation gradient of the second stress release channel according to the direction of the main stress release path, wherein the branch position determines the connection point between the second stress release channel and the first stress release channel, and the attenuation gradient determines the degree of stress reduction in the second stress release channel; The first stress release channel and the second stress release channel are connected according to the branch position and the attenuation gradient to form a stress gradient attenuation network, thereby determining a stress release path during the bonding process.

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