A method for optimizing and adjusting the rainbow pattern of ITOPET film

Abstract

This invention relates to the field of display optimization technology, and more particularly to a method for optimizing and adjusting rainbow patterns in ITOPET film. The method includes the following steps: determining the propagation direction of light in the display layer by establishing the angle relationship between the incident light path and the film layer normal of the ITOPET film; setting the cutting direction of the film material according to the angle parameter to form a preset angle with the display module; changing the refraction path of light between the ITO film and adjacent film layers by adjusting the cutting angle, and calculating the optical path difference between ordinary and extraordinary light; after bonding, detecting rainbow patterns on the display screen based on the optical path difference, and determining the cutting angle as the optimized angle when the interference fringes weaken or disappear. This invention achieves adaptive adjustment of the optical path difference by precisely controlling the cutting angle and incident light path of the ITOPET film, effectively suppressing or eliminating rainbow patterns, thereby significantly improving the brightness uniformity and optical display quality of the display module.

Description

Technical Field

[0001] This invention relates to the field of display optimization technology, and in particular to a method for optimizing and adjusting the rainbow pattern of an ITOPET film. Background Technology

[0002] Capacitive touchscreens are prone to rainbow patterns caused by light interference in complex and variable usage environments (such as outdoor use or wearing polarized sunglasses), which seriously affects the display effect and touch experience. PET substrates commonly used in display modules (such as diffusion films and brightness enhancement films) exhibit significant anisotropy due to the directional arrangement of molecular chains after biaxial stretching. When incident light enters, it splits into two beams of ordinary and extraordinary light with perpendicular polarization directions. The difference in propagation speed creates an optical path difference, which is further superimposed during the interaction and refraction with multilayer films such as polarizers and ITO films, ultimately forming a visible rainbow pattern.

[0003] Existing technologies typically reduce interference effects by employing In-Cell touch solutions or using optically isotropic OC / COP substrate films. However, the former is costly, has poor anti-interference capabilities, and lacks stability, while the latter, although effective in suppressing rainbow patterns, is expensive, difficult to process, and hard to apply widely. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for optimizing and adjusting the rainbow pattern of ITOPET film to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objective, a method for optimizing and adjusting the rainbow pattern of an ITOPET film is provided, the method comprising the following steps:

[0006] Step S1: Determine the incident light path relationship between the display layer and the ITOPET film in the touch screen module to be bonded, and obtain the angle parameter between the incident light and the film normal.

[0007] Step S2: Set the cutting direction of the ITOPET film based on the included angle parameter so that a preset included angle is formed between the cutting angle and the reference direction of the display module;

[0008] Step S3: By changing the cutting angle of the ITOPET film by setting a preset angle, the refraction path of light between the ITO film and its adjacent film layers is adjusted to obtain the optical path difference between ordinary light and extraordinary light.

[0009] Step S4: After bonding is completed, the rainbow pattern is visualized and detected on the display screen based on the optical path difference. If the interference fringes weaken or disappear, the cutting angle is determined to be the optimized angle.

[0010] The present invention has the following beneficial effects:

[0011] I. By establishing an incident light path model and cutting angle control mechanism for the ITOPET film, precise control of the interference effect between the display layer and the film layer was achieved, effectively suppressing or eliminating rainbow fringes. By determining the angle parameter between the incident light ray and the film layer normal, and setting the cutting direction of the ITOPET film based on this parameter, a preset angle is formed between the cutting angle and the reference direction of the display module, thereby changing the refraction path of the light in the film layer. This process can optimize the difference in propagation paths between ordinary and extraordinary light at the optical level, reducing the optical path difference caused by birefringence, and providing a stable geometric and optical basis for subsequent suppression of interference fringes.

[0012] Second, by extracting the refractive index and thickness data of each film layer in the display module, the refraction angle of incident light at the interface of each film layer and the propagation path length of the light are calculated, thereby obtaining the optical path difference between ordinary and extraordinary light. Combined with the reference optical path difference, the cutting angle is dynamically adjusted to achieve adaptive control of the optical path difference within an allowable range. By forming a controllable relative rotation angle between the upper and lower ITO films, this invention can refine the optical path design between the cutting layers to achieve optimal matching of the light refraction path, thereby significantly reducing the phase difference accumulation effect caused by the stacking of multiple films and improving the optical uniformity and stability of the display image.

[0013] Third, by introducing a dual-parameter interference quantitative evaluation mechanism that combines brightness uniformity and color difference, a shift from subjective visual judgment to objective data-driven evaluation has been achieved. By collecting brightness and color distribution information in real time within the interference intensity calculation area of ​​the display module, and establishing a coupled evaluation system of brightness uniformity index and color difference threshold, the actual interference intensity and distribution trend of rainbow patterns can be accurately reflected. Attached Figure Description

[0014] Figure 1 A schematic diagram of the steps for optimizing and adjusting the rainbow pattern of an ITOPET film;

[0015] Figure 2 for Figure 1 A detailed flowchart illustrating the implementation steps of step S3.

[0016] Figure 3 This is a schematic diagram of the rainbow pattern optimization and adjustment method for an ITOPET film according to this application, before optimization and adjustment.

[0017] Figure 4 This is a schematic diagram showing the optimized adjustment method for the rainbow pattern of an ITOPET film according to this application.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical method of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0021] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] To achieve the above objectives, please refer to Figures 1 to 4 A method for optimizing and adjusting the rainbow pattern of an ITOPET film, the method comprising the following steps:

[0023] Step S1: Determine the incident light path relationship between the display layer and the ITOPET film in the touch screen module to be bonded, and obtain the angle parameter between the incident light and the film normal.

[0024] In one embodiment, a sample of a touchscreen module to be bonded is selected, the structure of which includes a display layer (LCD or OLED display unit), an adhesive layer (optical adhesive OCA), and an ITOPET film layer. The sample is fixed on a precision optical inspection platform, which is equipped with an adjustable-angle incident light source assembly, an imaging angle measuring device, and a reflected light detection device.

[0025] The incident light source assembly uses a visible light source (wavelength range of 380nm to 780nm) and a collimating lens ensures that the beam perpendicularity accuracy is within ±0.05°. The imaging angle measuring device is set in the plane where the incident light ray and the normal to the display layer surface lie, and a high-resolution optical camera captures the incident and reflection paths of the light in real time.

[0026] The detection steps include: activating the light source and adjusting the incident angle of the light to illuminate the display layer surface at different angles. The path trajectories of the incident light and the reflected light from the film layer are captured using an optical camera. Based on the offset of the reflected light from the display layer surface and the change in the refractive interface, the angle between the incident light and the normal to the display layer is calculated using triangulation. When light passes through the display layer and enters the ITOPET film, a refraction path tracing algorithm is used (based on the interface refraction law). ), to obtain the refraction angle at the ITO layer interface The angle parameter between the incident light and the normal of the film layer is then deduced from this. The average value is obtained by measuring multiple points (at least 5 different incident angles) to obtain the incident light path relationship dataset between the display layer and the ITOPET film.

[0027] After the test is completed, the included angle parameters will be set. The parameters are stored in the calibration module and used as input parameters for subsequent rainbow ripple interferometry analysis to evaluate the interference and reflection characteristics of different film interfaces at specific angles.

[0028] Step S2: Set the cutting direction of the ITOPET film based on the included angle parameter so that a preset included angle is formed between the cutting angle and the reference direction of the display module;

[0029] In one embodiment, after determining the angle parameter between the incident light ray and the normal of the ITOPET film in the display module, this angle parameter is input into the film cutting control module to guide the setting of the film cutting direction. ITOPET film is typically composed of a PET substrate layer and an ITO conductive layer, and its optical properties and mechanical orientation characteristics vary with the cutting direction. To ensure stable and controllable optical interference performance after lamination, the orientation of the film material needs to be precisely set according to the angle parameter.

[0030] In practice, a reference coordinate system is first established based on the reference direction of the display module (usually the angle between the display surface of the module and the horizontal baseline). Then, based on the obtained angle parameters between the incident light ray and the normal to the film layer, a cutting direction vector forming a preset angle with the reference direction of the display module is calculated in this coordinate system. The preset angle is typically determined through experimental calibration, for example, set to a range of 5° to 25°, to balance optical interference control and material tensile strength.

[0031] Next, the control module transmits the calculated cutting direction vector to the CNC cutting equipment and adjusts the movement path of the cutting tool to precisely cut the ITOPET film along a preset angle. During this process, the tool offset and cutting speed are monitored in real time to ensure the smoothness of the film edge and the accuracy of interlayer alignment, thereby preventing uneven optical path difference caused by cutting errors. Through these steps, an ITOPET film with a cutting direction satisfying the preset angle relationship is finally obtained.

[0032] Step S3: By changing the cutting angle of the ITOPET film by setting a preset angle, the refraction path of light between the ITO film and its adjacent film layers is adjusted to obtain the optical path difference between ordinary light and extraordinary light.

[0033] In one embodiment, after obtaining the angle parameter between the incident light and the film normal, the cutting angle of the ITOPET film is precisely controlled according to a preset angle adjustment strategy. This preset angle is determined based on the structural stacking order of the display module and the optical anisotropy characteristics of the ITO film, and is generally adjustable within the range of 0° to 45°. When the cutting angle of the ITOPET film is adjusted, the refraction path of the incident light at the interface between the ITO conductive layer and the PET substrate film changes accordingly, thereby altering the propagation direction and distance of the light in different film layers.

[0034] In practice, the film material can be cut using a CNC cutting machine according to a preset angle, and the incident light refraction test can be performed on the cut film sample using a high-precision optical detection device. The changes in the deflection angles of the incident and refracted rays at the interfaces of each film layer are recorded, and the difference in the propagation length of the light within the ITO and PET layers is calculated. As the cutting angle changes, the refraction path of the light between the layers gradually changes from straight-line incidence to oblique incidence, resulting in a controllable change in the optical path difference (i.e., the difference in propagation distance between ordinary and extraordinary light).

[0035] Furthermore, by adjusting the included angle parameter, the optical path difference can be controlled within the sensitive range for interference fringe formation. For example, when the included angle increases, the optical path difference increases, and the changes in the density and brightness of the interference fringes become more pronounced; when the included angle decreases, the optical path difference decreases, and the interference fringes gradually weaken or even disappear. By comparing the correspondence between the changes in optical path difference under different cutting angles and the display effect, the optimal cutting angle can be determined, enabling the ITOPET film to effectively suppress or eliminate rainbow interference after being laminated to the display module, thereby improving the optical uniformity and visual consistency of the displayed image.

[0036] It is important to note that the ordinary ray (o-ray) and the extraordinary ray (e-ray) refer to the birefringence phenomenon that occurs when light propagates in anisotropic media (such as crystals). Birefringence refers to the fact that when light passes through anisotropic crystal materials, the speed of light propagation and the refractive index differ in different directions, causing the light to split into two beams with different propagation directions, speeds, and polarization states. In a birefringent crystal, the incident light splits into two beams: one called the "ordinary ray" (o-ray) and the other called the "extraordinary ray" (e-ray). These two beams have different propagation speeds, and therefore their refraction angles are also different, resulting in the splitting of the light beam.

[0037] Step S4: After bonding is completed, the rainbow pattern is visualized and detected on the display screen based on the optical path difference. If the interference fringes weaken or disappear, the cutting angle is determined to be the optimized angle.

[0038] In one embodiment, after the ITO-PET film is bonded to the display module, optical inspection of the display area is first performed. The inspection device illuminates the surface of the display panel with an incident light source within a specific wavelength range (e.g., the visible light band 400nm to 700nm) in a vertical or oblique manner. The reflected light is captured by a high-resolution optical sensor, forming image data containing interference fringe distribution, which is used to characterize the change in optical path difference between the ITO layer and the PET layer.

[0039] Subsequently, the acquired image data was processed using an interference fringe analysis algorithm. The algorithm first extracts the brightness distribution curve and color gradient information of the interference fringes. By calculating the spacing and brightness contrast of adjacent interference fringes, a visual distribution map of the optical path difference variation is obtained. If a significant rainbow-like pattern appears in the displayed image, it indicates a large optical path difference between different film layers, resulting in a significant reflection interference effect. Conversely, when the density of the interference fringes decreases, the brightness contrast weakens, or the color difference becomes more uniform, it indicates that the optical path difference between film layers tends to be minimal.

[0040] Based on this, the optical path difference distribution under different cutting angles was detected and compared one by one. By adjusting the cutting angle of the ITOPET film within a certain range (e.g., in 0.1° increments), and performing spectral analysis on the interference image corresponding to each angle, the visualization data of interference fringes at different angles was calculated. If the detection results show that the interference fringes are significantly weakened or completely disappeared at a certain specific angle, and the displayed image has uniform brightness and consistent color, then that angle is determined as the optimized cutting angle.

[0041] Finally, the determined optimized angle parameters are recorded and output for precise cutting and bonding operations in subsequent production processes. This method significantly reduces rainbow interference phenomena that occur after ITOPET film bonding, thereby improving the optical uniformity and visual quality of the display module.

[0042] As an example of the present invention, reference is made to Figure 2 As shown, step S3 in this example includes:

[0043] Step S31: Extract the refractive index and thickness data of each film layer in the display module;

[0044] Step S32: Based on the preset angle formed between the cutting angle and the reference direction of the display module, calculate the refraction angle of the incident light at the interface of each film layer and generate the corresponding refraction path data;

[0045] Step S33: Based on the refraction path data and the thickness data of each film layer, calculate the propagation distance of ordinary light and extraordinary light respectively;

[0046] Step S34: Calculate the optical path difference between ordinary and extraordinary light based on the propagation distance and refractive index to obtain the optical path difference.

[0047] In one embodiment, the display module undergoes layer structure analysis. The display module includes multiple film layers arranged sequentially from top to bottom, such as a protective glass layer, a touch layer, an ITO conductive layer, an adhesive layer, a polarizer layer, a display substrate layer, and a light-emitting layer. The film layers can be identified based on the display module's design drawings or physical samples. For design samples, the thickness and material number of each layer can be directly extracted from the process parameter table, and the refractive index parameters of the corresponding material in the target wavelength range (e.g., 380–780 nm) can be retrieved from the material database. For physical samples, the following steps can be used for measurement: an ellipsometer is used to measure the refractive index distribution of each layer, with measurement points covering the center and edge of the effective area of ​​the module to ensure the representativeness of the average data; a white light interferometric thickness gauge or a micro-thickness measurement system is used to obtain the thickness value of each layer; the measured refractive index and thickness data are input into a database to form a standardized layer parameter table. The data structure may include fields such as film layer number, material type, refractive index, thickness value, and measurement wavelength.

[0048] In this embodiment, the cutting angle of the display module is defined as the angle between the cutting direction of the film layer edge and the reference direction of the module (such as the horizontal display direction). First, the cutting angle of the current sample is obtained and a geometric relationship is established with the incident light direction. Taking the angle between the incident light and the module normal as the incident angle, the refraction angle of the light in each film layer is calculated layer by layer according to the refractive index of the two adjacent layers in the layer parameter table. The calculation process is performed in the order from the upper layer to the lower layer, generating incident angle and refraction angle mapping data for each layer. To ensure the accuracy of the results, a layered iterative algorithm is adopted, that is, after calculating the refraction angle of each layer, the refraction angle is automatically used as the incident angle input for the next layer, and then the angle calculation for the next layer is performed, until all film layers are traversed. Finally, a refraction path dataset is generated, which contains the incident angle, refraction angle, light propagation direction vector, and film layer number information for each layer.

[0049] In this embodiment, the refraction angle and layer thickness information of each layer are read from the refraction path data. For ordinary isotropic materials, the propagation path length of light within the layer is directly calculated. For films containing birefringence (such as polarizers, compensation films, etc.), the propagation paths of both ordinary and extraordinary light components need to be calculated separately. Based on the relationship between layer thickness and refraction angle, a propagation distance table is automatically generated, including the film layer number, light type (ordinary or extraordinary), incident angle, refraction angle, film thickness, and the calculated propagation path length. For films with angle-dependent characteristics (such as liquid crystal alignment layers or material layers with angular optical retardation), the effective propagation distance is corrected according to the incident angle, and the correction coefficient is recorded in the path table. After the propagation path lengths of all layers are calculated, a set of ordinary light propagation paths and a set of extraordinary light propagation paths are generated and stored as two independent data files for use in optical path calculation.

[0050] In this embodiment, the two sets of propagation paths generated in step S33 are read, and the light propagation of each layer is calculated by combining the corresponding refractive index data in the layer parameter table. First, the propagation amounts of ordinary light and extraordinary light in all film layers are accumulated to obtain the total light propagation result of both in the entire module. The difference between the two is defined as the optical path difference. The optical path difference is normalized, and the results are output separately according to wavelength ranges (e.g., red, green, and blue channels) for use in interference visualization analysis. If the variation amplitude of the optical path difference in the visible light band exceeds a preset threshold, it is automatically marked as a "high interference risk sample," prompting the process personnel that there may be a risk of rainbow patterns.

[0051] Preferably, calculating the optical path difference between ordinary and extraordinary light based on propagation distance and refractive index includes:

[0052] The effective propagation length of light within the film is determined by using the incident angle, exit angle, and propagation distance recorded in the refraction path data.

[0053] The effective propagation length is multiplied by the refractive index of the corresponding film layer to obtain the optical path length of ordinary light and the optical path length of extraordinary light, respectively.

[0054] The absolute difference between the ordinary optical path value and the extraordinary optical path value is taken as the optical path difference, and the optical path difference is compared with the preset reference optical path difference to determine whether the optical path difference is within the allowable range.

[0055] In one embodiment, an optical detection device is used to acquire refraction path data of an ITOPET film sample under specific incident conditions. The refraction path data includes the incident angle, the exit angle, and the propagation distance of the light within the film layer. Specifically, by setting the incident angle of the light source at 30° on the film surface, the detector acquires an exit angle of approximately 28.5°, and the measured propagation distance of the light within the film layer is 120 μm.

[0056] Secondly, based on the obtained refraction path data, the effective propagation length of light within the film layer is determined. Due to the slight tilt and interference effects at the film layer interface, this embodiment uses a path correction algorithm to correct the propagation distance, obtaining effective propagation lengths of ordinary light and extraordinary light in their respective propagation paths of 118.6 μm and 119.2 μm, respectively.

[0057] Then, the effective propagation lengths are multiplied by the refractive indices of the corresponding film layers to obtain the optical path lengths for ordinary and extraordinary light. Specifically, the refractive index of the ITO conductive layer is approximately 1.9, and the refractive index of the PET substrate layer is approximately 1.6. The calculated optical path length for ordinary light is 189.76 μm, and the optical path length for extraordinary light is 190.72 μm.

[0058] Next, the optical path difference between the two is calculated. By taking the absolute difference between the optical path value of the ordinary light and the optical path value of the extraordinary light, the optical path difference is found to be 0.96 μm.

[0059] Finally, the optical path difference is compared with a preset reference optical path difference range to determine if it is within the allowable range. In this embodiment, the reference optical path difference range is set to 0.8 μm ~ 1.2 μm. The detection results show that the current optical path difference is 0.96 μm, which is within the allowable range. Therefore, it is determined that the film interference in this region meets the requirements and will not produce obvious rainbow interference phenomena. If the detection result exceeds the allowable range, for example, if the optical path difference exceeds 1.2 μm, it will be automatically marked as a potential interference anomaly region, and a prompt will be made to adjust the film thickness or refractive index parameters to optimize the optical uniformity of the ITOPET film.

[0060] Preferably, determining whether the optical path difference is within the allowable range includes:

[0061] If the optical path difference is greater than the preset reference optical path difference, the cutting angle is increased to shorten the refraction path length;

[0062] If the optical path difference is less than the preset reference optical path difference, reduce the cutting angle to extend the refraction path length;

[0063] When the difference between the optical path difference and the preset reference optical path difference is lower than the preset optical path difference threshold, the current cutting angle is determined to be the optimized angle.

[0064] In one embodiment, the optical path difference calculated according to the aforementioned steps is obtained and compared with a preset reference optical path difference. In this embodiment, the reference optical path difference is set to 1.0 μm to characterize the ideal state where the interlayer interference is within the visually acceptable range. When the measured optical path difference is 1.25 μm, it indicates that the current optical path difference is greater than the reference optical path difference, and there is a slight interference enhancement phenomenon.

[0065] When the optical path difference exceeds a preset reference optical path difference, the control device executes a cutting angle adjustment command to increase the cutting angle, thereby shortening the refraction path length of light within the film. For example, if the initial cutting angle is 0° (i.e., parallel to the reference direction), and a large optical path difference is detected, the cutting angle is automatically increased to 3°. After adjustment, the refraction path is measured again, and the propagation distance is shortened from 120μm to 115μm. Calculations show that the new optical path difference is reduced to 1.02μm, close to the reference value.

[0066] Conversely, if the optical path difference is less than the preset reference optical path difference, for example, if the measured optical path difference is 0.82 μm, it indicates insufficient interference effect. In this case, the cutting angle is reduced by the control module to extend the refraction path length. Specifically, the original cutting angle is adjusted from 3° to 1°, and the propagation distance is remeasured to increase to 122 μm, with the corresponding optical path difference rising to 0.98 μm, approaching the reference value.

[0067] Finally, when the difference between the optical path difference and the reference optical path difference is lower than the preset optical path difference threshold, the current cutting angle is determined to be the optimized angle. In this embodiment, the optical path difference threshold is set to ±0.05μm. When the optical path difference of the adjusted detection result is 0.97μm, the difference between it and the reference optical path difference of 1.0μm is only 0.03μm, which is lower than the threshold, and the current cutting angle of 1° is determined to be the optimized angle. At this time, the interference fringes of the film layer basically disappear, and the rainbow pattern problem of the ITOPET film is significantly improved.

[0068] Preferably, step S32 includes:

[0069] The ITO conductive film layer in the ITOPET film is divided into an upper ITO film and a lower ITO film.

[0070] The upper ITO film is cut along the reference direction of the display module to obtain the upper ITO cut edge;

[0071] The lower ITO film is cut by rotating it relative to the upper ITO film by a preset angle to obtain the lower ITO cut edge;

[0072] A cutting angle is formed between the upper ITO cutting edge and the lower ITO cutting edge, and the angle between this cutting angle and the reference direction of the display module is used as the preset angle;

[0073] The corresponding refraction path data is generated based on the refraction angle of the incident light at the interface of each film layer.

[0074] In one embodiment, the ITO conductive film layer structure of the ITOPET film is divided into an upper ITO film and a lower ITO film. The upper ITO film and the lower ITO film are separated by a PET substrate layer with a thickness of approximately 100 μm. The upper ITO film is mainly used to connect with the touch electrode layer of the display module, while the lower ITO film contacts the underlying display light-emitting layer to realize the conduction of electrical signals and control of optical transmission.

[0075] Next, the upper ITO film is cut along the reference direction of the display module. In this embodiment, the reference direction is the long side direction of the display module. A high-precision laser cutting device is used to cut the upper ITO film in a straight line, forming a flat upper ITO cut edge. The laser cutting parameters are set to a power of 10W and a scanning speed of 100mm / s to ensure a smooth cut edge without any melted edges. After cutting, a microscopic inspection instrument is used to confirm that the straightness error of the upper ITO cut edge does not exceed ±0.05mm.

[0076] Then, the lower ITO film is cut by rotating it relative to the upper ITO film by a preset angle. To do this, the lower ITO film is first fixed on a reference platform, and the rotation control module rotates the lower ITO film relative to the cutting direction of the upper ITO film by a preset angle. .

[0077] In one specific embodiment, a preset angle The angle is set to 2°. The lower ITO film is cut along the rotation direction using the same laser cutting equipment to obtain the lower ITO cut edge. At this time, a set of tiny intersecting lines are formed between the upper and lower ITO cut edges to change the direction of light propagation.

[0078] Next, a cutting angle α is formed between the upper ITO cutting edge and the lower ITO cutting edge, and this cutting angle is... The angle between the reference direction of the display module and the reference direction is used as the preset angle. In this embodiment, the measurement is obtained through image recognition. It is 2.0°. The angle is 1.5°. This preset angle is used for subsequent geometric calculations of the incident light refraction path and interference compensation design.

[0079] Finally, the corresponding refraction path data is generated based on the refraction angle of the incident light at the interface of each film layer.

[0080] In this embodiment, a parallel light beam with a wavelength of 550 nm is incident on the film surface at a 30° angle. The light sequentially passes through the air / upper ITO film interface, the upper ITO film / PET layer interface, and the PET layer / lower ITO film interface. The refraction angles at each interface are obtained using an optical path tracing algorithm: the refraction angle at the air / upper ITO film interface is 15.6°; the refraction angle at the upper ITO film / PET layer interface is 18.2°; and the refraction angle at the PET layer / lower ITO film interface is 17.5°. Based on these refraction angles and the film thickness, refraction path data including the incident angle, exit angle, and propagation distance is calculated and stored in the optical path analysis module for subsequent optical path difference analysis and cutting angle optimization.

[0081] In another embodiment, reference can be made to Figure 3 and Figure 4 In the "before improvement" state, the conductive patterns of the upper and lower ITO films are basically aligned, both arranged along the same inclined direction, forming a parallel diagonal line structure. At this time, the angle between the upper and lower ITO patterns... Smaller, typically less than 5°, for example, as measured in this embodiment. =2°. Because the upper and lower ITO textures are oriented similarly, when incident light passes through the upper ITO film, the PET substrate layer, and the lower ITO film, the interference and superposition effect of light at the interface is quite significant, resulting in obvious rainbow patterns in local areas, such as uneven brightness and increased color difference fluctuations.

[0082] To improve this interference phenomenon, the ITOPET film structure was optimized in this embodiment, as shown in the "Improved" schematic diagram. Specifically, the conductive ripples of the upper and lower ITO films were designed to be perpendicular to each other, forming a 90° intersecting structure. That is, the upper ITO ripples are distributed along the long side of the display module, and the lower ITO ripples are distributed along the wide side, forming a uniform grid-like arrangement after combination. Through the above improvement, when incident light passes through the upper and lower ITO films, the reflection and refraction paths cancel each other out, and the interference fringes are significantly reduced. Experiments showed that under the conditions of an incident light angle of 30° and a wavelength of 550nm, the brightness uniformity of the improved sample increased from approximately 82% to 91%, the color difference value ΔE decreased from 2.8 to 1.1, and the interference rainbow fringes essentially disappeared.

[0083] Preferably, generating corresponding refraction path data based on the refraction angle of the incident light at each film layer interface includes:

[0084] Based on the preset angle, calculate the incident angle between the incident ray and the normal of each film layer;

[0085] By recording the refraction angles at the interfaces of each film layer using the incident angle and the refractive index of each film layer, a refraction angle dataset is generated.

[0086] The direction of light propagation within each film layer is determined based on the refraction angle dataset;

[0087] The corresponding refraction path data is generated based on the direction of propagation.

[0088] The process described in this embodiment is implemented in an optical design / inspection system. The system modules include: a sample stage, an adjustable incident light source, an angle measurement device, a film parameter database, a refraction angle calculation module, a ray tracing module, a path data storage module, and a visualization / verification module. The light source used in this example is monochromatic polarized light (wavelength 550 nm), the detector is a linear or area CCD array, and the sample stage has an angle control accuracy of ±0.01°.

[0089] The thickness, material type, and refractive index (or ordinary / unusual refractive index labels for anisotropic materials) of each film layer are read from the layer parameter table output in step S31. The layer parameter table fields include at least: film layer number, material identifier, thickness (unit: μm), refractive index identifier (or refractive index file reference), and interface normal direction vector. The preset included angle value determined in step S32 (this value is determined by the cut angle and the module reference direction), and the spatial direction of the incident light (e.g., the incident azimuth relative to the module normal) are read. This information is used as the geometric input for generating the refraction path.

[0090] A standard coordinate system is established within the system: the module surface normal serves as the local reference axis, and the module reference direction serves as the horizontal reference axis. A normal vector is determined for each membrane interface. The normal vector can be corrected based on the design drawing or the actual topography data obtained from surface contour scanning (if the surface has tilt or slight warping, the system will import the surface height map and adjust the interface normal accordingly).

[0091] Based on a preset angle and incident light direction, the system calculates the incident angle between the incident ray and the normal of the current layer's interface layer by layer. The implementation details are as follows: the incident light direction is represented as a combination of the tilt direction along the module normal and the projection direction within the module plane; for each interface, the normal vector of that interface is read, and the angle between the incident direction and the normal (incident angle) is calculated. This step is implemented in the software using a standard vector inner product / angle calculation function (common numerical libraries can be used for engineering implementation).

[0092] The incident angle and the material refractive index information of the current interface are used to determine the outgoing (refracted) angle, and the result is recorded as a refraction angle dataset.

[0093] Preferably, the generation of corresponding refraction path data based on the propagation direction includes:

[0094] The effective propagation path length of light in each film layer is calculated based on the refraction angle dataset.

[0095] The effective propagation path length of each film layer is accumulated according to the stacking order of the film layers based on the direction of light propagation in each film layer to obtain the total refraction path length of light.

[0096] The total refraction path length of the light and its layered paths are recorded as refraction path data.

[0097] In one embodiment, the refraction angle and film thickness parameters of each film layer are read from a refraction angle dataset. The film thickness data is provided by a film parameter table, output in step S31, and is in micrometers (μm). Based on the refraction angle and film thickness, the effective propagation path length of light within each film layer is calculated. This step is achieved through geometric relationships; that is, when incident light passes through a film layer at a certain refraction angle, its propagation path within the film layer is lengthened relative to the direction perpendicular to the thickness. The actual length of light propagation is determined based on the refraction angle and the film layer normal direction.

[0098] To ensure calculation accuracy, minor fluctuations or non-uniformities in the film thickness are considered when calculating the propagation length. For regions with thickness gradients, the film is divided into several micro-units (e.g., 0.1 mm × 0.1 mm), and the effective propagation length of each unit is calculated separately. Then, a weighted average is applied to the entire film to obtain accurate film propagation length data.

[0099] For films with directional optical properties (such as birefringent layers or composite conductive layers), the effective propagation path lengths of ordinary and extraordinary light are calculated separately, and a light type identifier is added to the results to distinguish them in subsequent optical path difference calculations.

[0100] After calculating the effective propagation path length of each film layer, these path lengths are accumulated according to the order of light propagation direction recorded in the refraction angle data set, following the order of the film layer stack structure, to obtain the total refraction path length of the light. The accumulation order is consistent with the light propagation order, that is, starting from the air incident interface, passing through the upper ITO film, PET layer, lower ITO film, etc., until the exit interface. If partial reflection or beam splitting of light is detected at a certain interface, the software will record the corresponding reflection path and transmission path as independent path branches, but the accumulation rules for each branch are the same.

[0101] To improve computational stability, path continuity is automatically checked during the accumulation process: if the difference between the incident and exit point coordinates of adjacent layers exceeds a set threshold (e.g., 10 nm), the geometric correction module is automatically triggered to recalculate the incident and refraction angles of adjacent layers to maintain the spatial continuity of the optical path. If non-planar features (such as curvature or uneven structures) are detected at the film interface, the propagation direction is corrected in the three-dimensional coordinate system using a surface fitting algorithm, and the path length is re-accumulated to ensure that the total path length accurately reflects the actual propagation distance of the light.

[0102] Once the total refraction path length of the light is calculated, the effective propagation path length of each film layer, the light propagation direction vector, and the total refraction path length are recorded together to generate complete refraction path data.

[0103] Preferred methods for dividing hierarchical paths include:

[0104] The coordinates of the incident and exit points of light in each film layer are determined based on the refraction angle dataset.

[0105] Using the interface between adjacent film layers as the dividing line, the effective propagation path length of light is divided into several independent segments according to the stacking order of the film layers;

[0106] In each segment, the effective propagation length of the segment is calculated based on the refraction angle dataset and the film thickness data.

[0107] The effective propagation length of each segment is mapped to the membrane layer to identify the layering path.

[0108] In one embodiment, the coordinates of the incident and exit points of light in each film layer are determined based on a refraction angle dataset. Taking an ITOPET film as an example, the sample sequentially includes an upper ITO conductive film layer, a PET substrate layer, and a lower ITO conductive film layer. Monochromatic light is irradiated onto the film surface at a set incident angle. The incident and exit positions of the light at each film layer interface are determined by microscopic observation or geometric calculation, and the corresponding coordinates are recorded to clarify the start and end points of light propagation at each interface.

[0109] Secondly, using the interfaces between adjacent film layers as boundaries, the effective propagation path length of light is divided into several independent segments according to the film layer stacking order. For example, the path of light from air into the upper ITO film is defined as the upper ITO segment, the path from the upper ITO film into the PET substrate layer is defined as the PET segment, and the path from the PET substrate layer into the lower ITO film is defined as the lower ITO segment. In this way, the propagation process of light in the multilayer film structure can be decomposed into continuous and measurable hierarchical segments, ensuring that the interface boundaries between each segment are clear and that each corresponding film layer is matched one-to-one.

[0110] Next, within each layer segment, the effective propagation length is calculated based on the refraction angle dataset and the film thickness data. When the film thickness is uniform, the propagation length of light within the film can be determined based on the geometric relationship between the incident angle and the refraction angle. When there are slight differences in film thickness, the average thickness value can be used for correction to improve the accuracy of the propagation length calculation. For films with birefringence properties, the propagation lengths of ordinary and extraordinary light rays in each layer can also be calculated separately for subsequent optical path difference analysis.

[0111] Finally, the effective propagation length of each segment is mapped to its corresponding film layer, forming a record of the light path in each layer. This record includes information such as the film layer name, the coordinates of the incident and exit points, the propagation length of the segment, and the film layer number. By summarizing all the segment data according to the stacking order of the film layers, the complete refraction path of light in the entire ITOPET film structure can be obtained. Through the above steps, the propagation behavior of light in multilayer films can be clearly characterized, providing a reliable data foundation for subsequent optical path difference calculations and rainbow interference analysis.

[0112] Preferably, step S4 includes:

[0113] After bonding is completed, the structural parameters of the display module are obtained and correlated with the optical path difference to determine the interference intensity calculation area;

[0114] Within the interference intensity calculation area, collect the brightness distribution information and color distribution information of the displayed image;

[0115] The uniformity of brightness distribution information and the color difference value of color distribution information are used to perform quantitative evaluation of interference and generate rainbow fringe detection data, which is used to evaluate interference fringes.

[0116] The optimal cutting angle is determined based on the rainbow pattern detection data.

[0117] In one embodiment, after the ITOPET film is bonded to the display module, the structural parameters of the display module are acquired and correlated with the optical path difference to determine the interference intensity calculation region. The structural parameters of the display module include information such as the thickness, refractive index, bonding sequence, and interface reflectivity of each film layer. By comparing these parameters with the previous optical path difference calculation results, local areas with significant changes in optical path difference can be identified as interference-sensitive regions. These interference-sensitive regions are further defined as interference intensity calculation regions for subsequent interference fringe detection.

[0118] Next, the brightness and color distribution information of the displayed image are acquired within the interference intensity calculation area. Brightness distribution information can be acquired using an optical microscopic imaging system under standard illumination conditions. The display module is kept stably lit, and the sample area is photographed from both a vertical viewing angle and a 45° oblique viewing angle to obtain the original brightness distribution images. Color distribution information can be acquired using a colorimeter or a high-resolution RGB camera to obtain the color coordinate values ​​(L, a, b) of each pixel. After the brightness and color data acquisition is completed, the raw data is denoised and normalized to ensure the accuracy of subsequent analysis.

[0119] Subsequently, quantitative interference evaluation was performed using the brightness uniformity of the brightness distribution information and the color difference value of the color distribution information to generate rainbow pattern detection data. Brightness uniformity reflects the spatial fluctuation of the displayed image's brightness, while the color difference value characterizes the degree of color shift between adjacent areas. This is achieved by calculating the brightness uniformity coefficient and the color difference... The brightness uniformity and color difference value can be used to determine the significance of interference fringes. If the brightness change rate is high or the color difference value exceeds the visible threshold, it indicates the presence of obvious interference fringes in that area. The results corresponding to the brightness uniformity and color difference values ​​of each area are quantified and fused to generate rainbow fringe detection data that includes interference intensity, interference direction, and interference distribution pattern. This data can intuitively reflect the distribution characteristics and intensity changes of the rainbow fringe after bonding.

[0120] Finally, the optimal cutting angle is determined based on the rainbow pattern detection data. By comparing the rainbow pattern detection data obtained under different cutting angle conditions, the angle parameter with the lowest interference intensity, the most uniform brightness, and the smallest color difference is identified. When the interference intensity value in the rainbow pattern detection data is lower than a preset threshold, the corresponding cutting angle is determined to be the optimal angle. This optimal angle is the best geometric parameter for the ITOPET film to effectively suppress the formation of rainbow patterns when it is laminated to the display module.

[0121] Preferably, the quantitative evaluation of interference using the brightness uniformity of brightness distribution information and the color difference value of color distribution information includes:

[0122] When the brightness uniformity improves from below 85% to above 90%, and the brightness fluctuation range decreases from more than ±10 cd / m², 2 Reduced to ±3 cd / m 2 When the color difference value of adjacent interference intensity calculation areas decreases from greater than 2.5 to less than 1.0, the interference fringes are considered to be significantly weakened; when the uniformity of brightness distribution is ≥95% and the color difference value of the entire interference intensity calculation area is less than 0.5, the interference fringes are considered to have disappeared.

[0123] In one embodiment, within the interference intensity calculation region, the brightness distribution data of the display module is first statistically analyzed to calculate the brightness uniformity and brightness fluctuation amplitude. Brightness uniformity represents the consistency between the brightness at each measurement point and the average brightness, while brightness fluctuation amplitude reflects the magnitude of local brightness changes. After adjusting the cutting angle or bonding tension of the ITOPET film, the brightness uniformity was observed to increase from below 85% to above 90%, and the brightness fluctuation amplitude decreased from over ±10 cd / m. 2 Reduced to ±3 cd / m 2 When the value is within a certain range, it indicates that the interference superposition phenomenon of light in the film layer is significantly weakened, and the contrast of the interference fringes decreases significantly.

[0124] Simultaneously, the color distribution information of the same area was analyzed, and the color difference value ΔE was used to characterize the color deviation between adjacent areas. When the color difference value of adjacent interference intensity calculation areas decreased from greater than 2.5 to less than 1.0, it indicated that the phase interference caused by the optical path difference had been significantly weakened, and the displayed image tended to have consistent colors. Considering the changes in brightness and color difference, with brightness uniformity ≥90% and brightness fluctuation amplitude ≤±3 cd / m², [the desired result was achieved]. 2 Furthermore, if the color difference value is less than 1.0, it can be determined that the interference fringes are significantly weakened.

[0125] Furthermore, after optimizing the cutting angle, the test results showed that the uniformity of the brightness distribution improved to over 95%, and the color difference value in the full interference intensity calculation area was less than 0.5. This indicates that the optical path difference has become balanced, the interference effect has been completely suppressed, and the rainbow stripe phenomenon has disappeared. The cutting angle at this point is the optimal bonding angle, which can be used as a standard parameter for ITOPET film in subsequent mass production.

[0126] Of particular importance, step S2, which involves setting the cutting direction of the ITOPET film based on the included angle parameter, also includes:

[0127] The ITOPET film to be cut is fixed on a vacuum adsorption platform to ensure that the film surface is flat and to establish an alignment reference with the display module reference direction;

[0128] The rotation angle of the ITOPET film is adjusted according to the included angle parameter by a rotary positioning mechanism with an angle scale or an electronically controlled servo rotary table, so that the cutting direction forms a preset included angle with respect to the reference direction of the display module.

[0129] The ITOPET film is linearly cut along the set direction using a laser cutting device. The laser cutting power is controlled between 8W and 10W, the scanning speed is controlled at about 100mm / s, and the focal length is set 0.2mm above the film surface to ensure that the cut edge is smooth and the conductive layer is continuous.

[0130] After cutting, the angle and straightness of the cut edge are detected by a microscopic inspection instrument to confirm that the angle deviation between the cutting angle and the reference direction of the display module does not exceed ±0.05°, so as to ensure that the cutting direction of the ITOPET film conforms to the preset angle design.

[0131] In one embodiment, the ITOPET film to be cut is laid flat and fixed on a vacuum adsorption platform to form a stable, bubble-free, flat film surface. Vacuum adsorption effectively prevents minor warping or displacement of the film material during the cutting process, thus ensuring consistency between the cutting path and the set direction. After fixing, the operator uses an alignment marking system to establish a precise alignment relationship between the edge reference line of the ITOPET film and the reference direction of the display module, providing a stable spatial reference for subsequent angle adjustments.

[0132] Subsequently, a rotary positioning mechanism with high-precision angle scale or an electronically controlled servo rotary table is used to rotate and adjust the ITOPET film. The operator inputs the angle value according to the preset angle parameters to ensure that the cutting direction and the reference direction of the display module form a preset angle. To ensure adjustment accuracy, the resolution of the rotary positioning mechanism is controlled within 0.01°, and the angle response error of the electronically controlled servo system does not exceed ±0.02°. After the angle setting is completed, the system automatically locks the rotary mechanism to prevent angular deviation during the cutting process.

[0133] After setting the angle, the laser cutting equipment is activated to perform a straight cut on the ITOPET film. The cutting power of the laser equipment is set between 8W and 10W, the scanning speed is controlled at approximately 100mm / s, and the laser focal length is precisely positioned 0.2mm above the film surface to ensure uniform laser energy distribution, smooth cut edges, and preservation of the continuity of the ITO conductive layer. The entire cutting process is carried out in a constant temperature environment to avoid micro-deformation of the film material due to heat, thereby ensuring the stability of the cutting angle and edge line shape.

[0134] After setting the angle, the laser cutting equipment is activated to perform a straight cut on the ITOPET film. The cutting power of the laser equipment is set between 8W and 10W, the scanning speed is controlled at approximately 100mm / s, and the laser focal length is precisely positioned 0.2mm above the film surface to ensure uniform laser energy distribution, smooth cut edges, and preservation of the continuity of the ITO conductive layer. The entire cutting process is carried out in a constant temperature environment to avoid micro-deformation of the film material due to heat, thereby ensuring the stability of the cutting angle and edge line shape.

[0135] After cutting, the cut edges are inspected using a high-magnification microscope. The inspection includes angular accuracy and straightness evaluation: the microscope measures the angular deviation between the cut edge and the reference direction, confirming that the angular deviation is controlled within ±0.05°. Simultaneously, an edge straightness analysis algorithm is used to evaluate the edge straightness, ensuring that the linear fluctuation does not exceed 0.1mm. If the inspection results meet the preset standards, the cutting direction is considered correctly set, and the material can be used as a qualified substrate for subsequent film lamination and optical interference optimization.

[0136] Of particular importance is the use of a microscopic inspection instrument to detect the angle and straightness of the cut edge, including:

[0137] Microscopic imaging of the cut edge of the ITOPET film was performed to obtain an image of the cut edge;

[0138] Extract the edge contour lines of the cropped edge image and calculate the angle between the edge contour lines and the reference direction of the display module to obtain the cropped edge angle detection result;

[0139] Straightness analysis is performed based on the linearity of the cropped edge image to detect the fluctuation amplitude of the cropped edge in the length direction, so as to obtain the straightness detection result of the cropped edge.

[0140] In one embodiment, the cut ITOPET film sample is fixed on a microscopic inspection platform, and a high-precision microscopic inspection instrument is used to perform microscopic imaging of the cut edge area. The magnification of the microscopic inspection instrument is set in the range of 100x to 500x to clearly capture the fine morphology of the conductive layer boundary and the cut line of the ITOPET film. The imaging system is equipped with a line-scanning CCD camera component, which acquires continuous images of the cut edge by scanning line by line, generating high-resolution cut edge image data.

[0141] Subsequently, edge contour lines are extracted from the acquired cropped edge images. The system automatically identifies the pixel boundaries at the interface between the conductive layer and the air using a grayscale gradient detection algorithm, and then uses a least-squares fitting method to fit the extracted pixel points to edge curves, thereby forming accurate edge contour lines. By establishing an image coordinate reference for the display module's reference direction, the angle between the edge contour line and the reference direction is calculated, thus obtaining the cropping edge angle detection result. The detection result is output in the form of angle values, with an angle measurement resolution better than 0.01°, used to evaluate the consistency between the cropping direction and the preset angle design.

[0142] Next, the system performs a straightness analysis on the linearity of the cropped edge image. The detector calculates the offset of the edge contour line segment by segment along the entire length of the cropped edge, and uses the least squares fitted straight line as a reference to obtain the maximum and average deviation values ​​at each detection point. If the maximum fluctuation of the edge contour line is less than 0.1 mm and the average deviation is less than 0.05 mm, the straightness of the cropped edge is deemed acceptable.

[0143] Finally, the microscopic inspection instrument outputs the angle and straightness test results together to generate a cutting quality assessment report. If the angle deviation is less than ±0.05° and the straightness meets the design requirements, the cutting accuracy of the ITOPET film is confirmed to meet the optical bonding requirements, and it can directly proceed to the next bonding and interference testing process.

[0144] Therefore, the embodiments should be considered as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the application are intended to be included within the invention.

[0145] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method for optimizing and adjusting the rainbow pattern of an ITOPET film, applied to the ITO conductive film layer and the PET substrate film layer in an ITOPET film, characterized in that, Includes the following steps: Step S1: Determine the incident light path relationship between the display layer and the ITOPET film in the touch screen module to be bonded, and obtain the angle parameter between the incident light and the film normal. Step S2: Set the cutting direction of the ITOPET film based on the included angle parameter so that a preset included angle is formed between the cutting angle and the reference direction of the display module; Step S3: By changing the cutting angle of the ITOPET film through a preset angle, the refraction path of light between the ITO film and its adjacent layers is adjusted to obtain the optical path difference between ordinary and extraordinary light; wherein, step S3 includes the following steps: Step S31: Extract the refractive index and thickness data of each film layer in the display module; Step S32: Based on the preset angle formed between the cutting angle and the reference direction of the display module, calculate the refraction angle of the incident light at the interface of each film layer and generate the corresponding refraction path data; Step S33: Based on the refraction path data and the thickness data of each film layer, calculate the propagation distance of ordinary light and extraordinary light respectively; Step S34: Calculate the optical path difference between the ordinary ray and the extraordinary ray based on the propagation distance and refractive index to obtain the optical path difference; wherein, step S32 includes: The ITO conductive film layer in the ITOPET film is divided into an upper ITO film and a lower ITO film. The upper ITO film is cut along the reference direction of the display module to obtain the upper ITO cut edge; The lower ITO film is cut by rotating it relative to the upper ITO film by a preset angle to obtain the lower ITO cut edge; A cutting angle is formed between the upper ITO cutting edge and the lower ITO cutting edge, and the angle between this cutting angle and the reference direction of the display module is used as the preset angle; Generate corresponding refraction path data based on the refraction angle of the incident light at the interface of each film layer; Step S4: After bonding is completed, the rainbow pattern is visualized and detected on the display screen based on the optical path difference. If the interference fringes weaken or disappear, the cutting angle is determined to be the optimized angle.

2. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 1, characterized in that, The optical path difference between ordinary and extraordinary rays, calculated based on propagation distance and refractive index, includes: The effective propagation length of light within the film is determined by using the incident angle, exit angle, and propagation distance recorded in the refraction path data. The effective propagation length is multiplied by the refractive index of the corresponding film layer to obtain the optical path length of ordinary light and the optical path length of extraordinary light, respectively. The absolute difference between the ordinary optical path value and the extraordinary optical path value is taken as the optical path difference, and the optical path difference is compared with the preset reference optical path difference to determine whether the optical path difference is within the allowable range.

3. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 2, characterized in that, Determining whether the optical path difference is within the allowable range includes: If the optical path difference is greater than the preset reference optical path difference, the cutting angle is increased to shorten the refraction path length; If the optical path difference is less than the preset reference optical path difference, reduce the cutting angle to extend the refraction path length; When the difference between the optical path difference and the preset reference optical path difference is lower than the preset optical path difference threshold, the current cutting angle is determined to be the optimized angle.

4. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 1, characterized in that, Based on the refraction angle of the incident light at each film layer interface, the corresponding refraction path data is generated, including: Based on the preset angle, calculate the incident angle between the incident ray and the normal of each film layer; By recording the refraction angles at the interfaces of each film layer using the incident angle and the refractive index of each film layer, a refraction angle dataset is generated. The direction of light propagation within each film layer is determined based on the refraction angle dataset; The corresponding refraction path data is generated based on the direction of propagation.

5. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 4, characterized in that, The corresponding refraction path data is generated based on the direction of propagation, including: The effective propagation path length of light in each film layer is calculated based on the refraction angle dataset. The effective propagation path length of each film layer is accumulated according to the stacking order of the film layers based on the direction of light propagation in each film layer to obtain the total refraction path length of light. The total refraction path length of the light and its layered paths are recorded as refraction path data.

6. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 5, characterized in that, Methods for dividing hierarchical paths include: The coordinates of the incident and exit points of light in each film layer are determined based on the refraction angle dataset. Using the interface between adjacent film layers as the dividing line, the effective propagation path length of light is divided into several independent segments according to the stacking order of the film layers; In each segment, the effective propagation length of the segment is calculated based on the refraction angle dataset and the film thickness data. The effective propagation length of each segment is mapped to the membrane layer to identify the layering path.

7. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 1, characterized in that, Step S4 includes: After bonding is completed, the structural parameters of the display module are obtained and correlated with the optical path difference to determine the interference intensity calculation area; Within the interference intensity calculation area, collect the brightness distribution information and color distribution information of the displayed image; The uniformity of brightness distribution information and the color difference value of color distribution information are used to perform quantitative evaluation of interference and generate rainbow fringe detection data, which is used to evaluate interference fringes. The optimal cutting angle is determined based on the rainbow pattern detection data.

8. The method for optimizing and adjusting the rainbow pattern of ITOPET film according to claim 1, characterized in that, Quantitative evaluation of interference using luminance distribution information for luminance uniformity and color distribution information for color difference includes: When the brightness uniformity increases from below 85% to above 90%, the brightness fluctuation range decreases from more than ±10 cd / m² to within ±3 cd / m², and the color difference value of adjacent interference intensity calculation areas decreases from greater than 2.5 to less than 1.0, the interference fringes are considered to be significantly weakened; when the brightness distribution uniformity is ≥95% and the color difference value of the entire interference intensity calculation area is less than 0.5, the interference fringes are considered to have disappeared.

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