A packaging structure for realizing narrow frame of four sides of a display screen and a preparation method thereof

Abstract

The application discloses a packaging structure for realizing narrow frames of four sides of a display screen and a preparation method thereof, and relates to the technical field of display device packaging. The packaging structure comprises a display panel main body, the display panel main body comprises a first substrate, a second substrate and an optical film layer attached to the surface of the second substrate, a flexible circuit board bending area is formed between the first substrate and the optical film layer, and a functional adhesive packaging assembly is arranged in the flexible circuit board bending area. The functional adhesive packaging assembly replaces the protection, shielding and structural support functions of a traditional metal or plastic frame. The structure reduces the lower frame from 15-20 mm to below 5 mm, realizes equal width of four sides, passes through a rigorous reliability test, is suitable for various displays such as LCD and OLED, and has good high-temperature and high-humidity resistance and repair performance.

Description

Technical Field

[0001] This invention relates to the field of display device packaging technology, and in particular to a packaging structure for achieving a narrow bezel on all four sides of a display screen and its manufacturing method. Background Technology

[0002] Full-screen displays are the mainstream development trend of consumer electronics display products, and achieving a "true full-screen" with equal width on all four sides is a goal that the industry continues to pursue. In the manufacturing process of traditional displays (especially LCDs), when the flexible circuit board (such as COF, COP) on which the driver IC is attached is bent to the back of the glass substrate, an unavoidable physical step is formed. At the same time, there is also a step difference between the glass substrate of the display module and the optical film layer (such as the polarizer POL) at the edge.

[0003] To protect the aforementioned vulnerable structural areas, shield internal wiring, and provide sufficient structural strength to withstand the weight of the glass screen and external stress, traditional solutions generally employ a frame structure (often called a "decorative strip" or "iron frame") made of metal (such as aluminum alloy, magnesium alloy, or stainless steel) or engineering plastics (such as PC plastic, ABS plastic, or PC / ABS composite material) for enclosure and fixation. To ensure strength and safety, the bottom bezel of this type of rigid frame typically needs to be 15mm to 20mm wide, severely limiting the improvement of screen-to-body ratio and product aesthetics.

[0004] The industry has attempted to use adhesives to fill the platform steps to narrow the bottom bezel, but most attempts have failed. The core reason is that ordinary adhesives cannot simultaneously meet two key requirements: First, their structural bonding performance is insufficient, and they cannot replace the metal frame in bearing the weight of the glass screen and meeting long-term reliability requirements, posing a risk of detachment or cracking. Second, their appearance consistency is substandard. Commonly used adhesives (such as light blue or semi-transparent glue) differ significantly from the pure black appearance of the polarizer when the monitor is off in terms of color and light-blocking properties, making them unable to "hide" in the bezel. This results in obvious visual color blocks or light transmission when the screen is off, forcing designers to retain a certain width of decorative strips for covering.

[0005] Therefore, developing adhesives and special encapsulation structures that combine high-strength structural bonding with aesthetic consistency has become a key technology for achieving narrow bezels on all four sides of a display. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of the prior art and provide a packaging structure and manufacturing method for achieving a narrow bezel on all four sides of a display screen. By using a self-developed adhesive system and a precision dispensing packaging structure, it replaces the key role of the traditional metal / plastic bezel in the bottom bezel, significantly reducing the width of the bottom bezel and achieving an aesthetically pleasing visual effect with a narrow bezel on all four sides.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a packaging structure for realizing a narrow bezel on all four sides of a display screen, comprising a display panel body, the display panel body including a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate, a flexible circuit board bending area being formed between the first substrate and the optical film layer, and a functionalized adhesive encapsulation component being provided within the flexible circuit board bending area, the functionalized adhesive encapsulation component replacing the protective, shielding, and structural support functions of traditional metal or plastic bezels, the functionalized adhesive encapsulation component consisting of the following two parts:

[0008] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0009] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0010] Preferably, the first substrate is a TFT substrate; the second substrate is a CF substrate or encapsulation glass; and the optical film is a POL film.

[0011] Preferably, both the black encapsulating adhesive and the black edge sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-blocking performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge sealing adhesive is used to construct a shaping edge sealing layer to prevent light leakage and water vapor penetration.

[0012] Preferably, the functionalized adhesive encapsulation component reduces the width of the bottom bezel of the display screen from 15-20mm of traditional metal / plastic bezels to less than 5mm, and more preferably to 3mm or less.

[0013] Preferably, the independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are: 30-40 parts of flexible polyurethane acrylate resin, 10-15 parts of vinyl fluorinated hyperbranched silicone resin, 2-3 parts of photoinitiator, 40-50 parts of reactive diluent, 0.1-0.5 parts of antioxidant, 0.3-1 parts of leveling agent, 0.3-0.8 parts of coupling agent, 3-5 parts of other functional monomers, and 0.2-0.5 parts of black pigment; wherein the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-ylidene)bis(methylene)diacrylate compounded in a mass ratio of 2:(0.8-1.2):(0.3-0.5).

[0014] Preferably, the flexible polyurethane acrylate resin is Evonik EBECRIL® 270 or BASF Laromer. The product is a mixture of one or more of UA9030 and Sartoma CN9006NS; the source of the vinyl fluorinated hyperbranched silicone resin is not particularly required. In one embodiment of the present invention, the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 of the invention patent document CN119192582B; the photoinitiator is at least one of photoinitiator 184, photoinitiator 369, photoinitiator 651, photoinitiator 784, photoinitiator 819, photoinitiator 907, photoinitiator 1173, and photoinitiator 2959; the reactive diluent is one or any mixture of isobornyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 4-acryloylmorpholine, and ethoxylated trimethylolpropane triacrylate; the antioxidant is at least one of Irganox 1010, Irganox 1135, Irgafos 168, and Irgafos 126.

[0015] Preferably, the leveling agent is at least one of leveling agent TEGO450, leveling agent TEGO410, and leveling agent TEGO Glide100; the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570; and the black pigment is one or any mixture of black pigment D45, black pigment U4115, and black pigment U4117.

[0016] Another object of the present invention is to provide a method for manufacturing the above-mentioned packaging structure for achieving a narrow bezel on all four sides of a display screen, comprising the following steps:

[0017] Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 30-50 min at 25-30℃ and 600-800 rpm / min. Then, vacuum stir for 40-60 min at 1500-2000 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained.

[0018] Step S2, Pre-treatment: Perform plasma cleaning treatment on the bending area of ​​the flexible circuit board to remove surface contaminants and impurities;

[0019] Step S3, Encapsulating Adhesive Dispensing: Using a piezoelectric valve dispensing system, black encapsulating adhesive is precisely dispensed into the steps and gaps of the flexible circuit board bending area to completely fill them and make them flush with the design reference plane of the second substrate.

[0020] Step S4, edge sealing adhesive application: Using a piezoelectric valve dispensing system, black edge sealing adhesive is precisely applied to the surface of the black encapsulating adhesive, the exposed structure in the bending area of ​​the flexible circuit board, and the gaps between components, so that it completely covers the exposed structure and seamlessly connects with the edge of the optical film layer.

[0021] Step S5, UV curing treatment: Vertical irradiation with an LED-UV light source with a wavelength of 405nm, curing energy ≥10000mJ / cm², to completely cure the black encapsulating adhesive and black edge sealing adhesive.

[0022] Preferably, the piezoelectric valve dispensing system achieves precise control of adhesive volume by adjusting the air pressure parameters (0.2-0.4MPa), voltage output (6-10V), and operating frequency (80-150Hz), with a dispensing accuracy error of ≤±0.1mm.

[0023] Preferably, a step-by-step curing step is included between step S3 and step S4, specifically: first, the black encapsulating adhesive is UV pre-cured with a curing energy of 10000-12000mJ / cm² and a curing time of 30-40s.

[0024] Preferably, after step S5, an appearance inspection step is also included, in which color difference detection is performed on the cured functionalized adhesive encapsulation component to ensure that the color of the adhesive meets the standard of consistency with the optical film layer; at the same time, appearance defect detection is performed to check for problems such as excess adhesive, insufficient adhesive, and bubbles.

[0025] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0026] (1) The encapsulation structure and its preparation method for achieving a narrow bezel on all four sides of a display screen disclosed in this invention, wherein the independent formulations of the black encapsulating adhesive and the black edge sealing adhesive are, by weight, as follows: 30-40 parts of flexible polyurethane acrylate resin, 10-15 parts of vinyl fluorinated hyperbranched silicone resin, 2-3 parts of photoinitiator, 40-50 parts of reactive diluent, 0.1-0.5 parts of antioxidant, 0.3-1 part of leveling agent, 0.3-0.8 parts of coupling agent, 3-5 parts of other functional monomers, and 0.2-0 parts of black pigment. 0.5 parts; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-ylidene)bis(methylene)diacrylate in a mass ratio of 2:(0.8-1.2):(0.3-0.5); through the synergistic effect of the components, the prepared UV black glue has the characteristics of extreme filling, strong light blocking, resistance to extreme environments, and high number of repairs without damage, and can completely replace the function of traditional metal / plastic frames.

[0027] (2) The encapsulation structure and preparation method for achieving a narrow bezel on all four sides of the display screen disclosed in this invention adopts a functional monomer system of bisphenol A epoxy acrylate, allyl-β-cyclodextrin and (octahydro-4,7-methylene-1H-indene-1,5-ylidene)bis(methylene)diacrylate in a specific mass ratio. This system breaks through the performance limitations of traditional single functional monomers, enabling the adhesive to have both excellent flexibility and rigidity. It can adapt to slight deformation during the assembly and use of the display panel, avoid cracking, and provide structural support strength sufficient to replace the metal / plastic bezel. This solves the technical pain point of existing adhesives that "structural strength and flexibility cannot be obtained at the same time".

[0028] (3) The encapsulation structure and its preparation method for achieving a narrow bezel on all four sides of the display screen disclosed in this invention successfully reduces the width of the bottom bezel of the display screen from the traditional 15-20mm to less than 5mm, or even 3mm, by replacing the bulky metal or plastic bezel with a high-performance black adhesive system. This shortens the width to be consistent with the width of the narrow bezels on the other three sides, achieving a true "equal width on all four sides" full-screen visual effect. The black adhesive used simultaneously meets the dual requirements of structural filling and appearance shielding. The black encapsulating adhesive is responsible for solving the physical steps and providing structural strength, while the black edge sealing adhesive is responsible for the final appearance consistency and full light shielding. The two work together to achieve the unity of structure and aesthetics.

[0029] (4) The encapsulation structure and its preparation method for achieving a narrow bezel on all four sides of the display screen disclosed in this invention adopts a piezoelectric valve dispensing system to achieve ultra-high precision glue control and positioning. Through the precise ratio of black pigment and the compatibility design of the resin system, the color difference ΔE between the adhesive and the optical film layer after curing is ≤2.0, and it has 100% light-shielding performance, achieving perfect "invisibility" in the screen-off state, without visual defects such as light transmission or color blocks.

[0030] (5) The packaging structure and preparation method for realizing a narrow bezel on all four sides of the display screen disclosed in this invention have lower adhesive material costs and simpler processing flow compared with metal / plastic bezels. They do not require metal cutting or plastic injection molding, reducing energy consumption and waste emissions, and are both economical and environmentally friendly. They are applicable to various display products such as LCD, OLED, Mini-LED, and Micro-LED, and provide a new technical path for the upgrade of full-screen display technology. Attached Figure Description

[0031] Figure 1 This is a schematic diagram comparing the border width of a traditional metal / plastic frame encapsulation structure with the adhesive encapsulation structure of this invention.

[0032] Figure 2 This is a schematic cross-sectional view of the process for preparing the encapsulation structure in Embodiment 1 of the present invention.

[0033] Figure 3 This is a schematic cross-sectional view of the process for preparing the encapsulation structure in Embodiment 2 of the present invention.

[0034] in, Figure 1 Explanation of the award number: Figure 1 In this context, A represents the traditional bottom bezel structure of a display screen (metal / plastic), with a bottom bezel width W1 = 15-20mm; Figure 1 In this context, B refers to the bottom bezel structure of the display screen using the technology of this invention, with a bottom bezel width W2 = 3-5mm (W2 << W1).

[0035] Figure 2 and Figure 3 Explanation of the designation numbers: 1. First substrate (TFT substrate); 2. Second substrate (CF / encapsulation glass); 3. Optical film (POL film); 4. Flexible circuit board bending area (COF); 5. Black encapsulating adhesive; 6. Black edge sealing adhesive. Detailed Implementation

[0036] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0037] Example 1: A packaging structure for achieving a narrow bezel on all four sides of a display screen includes a display panel body. The display panel body comprises a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate. A flexible circuit board bending area is formed between the first substrate and the optical film layer. A functional adhesive encapsulation component is provided within the flexible circuit board bending area. The functional adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic bezels. The functional adhesive encapsulation component consists of the following two parts:

[0038] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0039] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0040] Both the black encapsulating adhesive and the black edge sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-blocking performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge sealing adhesive is used to construct a shaping edge sealing layer to prevent light leakage and water vapor penetration.

[0041] The functionalized adhesive encapsulation assembly reduces the width of the bottom bezel of the display from 15-20mm for traditional metal / plastic bezels to 3mm.

[0042] The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 30 parts flexible polyurethane acrylate resin, 10 parts vinyl fluorinated hyperbranched silicone resin, 2 parts photoinitiator, 40 parts reactive diluent, 0.1 parts antioxidant, 0.3 parts leveling agent, 0.3 parts coupling agent, 3 parts other functional monomers, and 0.2 parts black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-ylidene)bis(methylene)diacrylate in a mass ratio of 2... The mixture is composed of a 0.8:0.3 ratio; the flexible polyurethane acrylate resin is Evonik EBECRIL® 270; the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 in Chinese Patent Document CN119192582B; the photoinitiator is photoinitiator 184; the reactive diluent is isobornyl methacrylate; the antioxidant is Irganox 1010; the leveling agent is leveling agent TEGO 450; the coupling agent is silane coupling agent KH 550; and the black pigment is black pigment D45.

[0043] A method for fabricating the above-mentioned encapsulation structure that achieves a narrow bezel on all four sides of the display screen, such as... Figure 2 It includes the following steps:

[0044] Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 30 min at 25℃ and 600 rpm / min. Then, vacuum stir for 40 min at 1500 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained.

[0045] Step S2, Pretreatment: Plasma cleaning is performed on the flexible circuit board (COF) bending area 4 of the lower frame to remove contaminants and enhance adhesion;

[0046] Step S3, Applying encapsulating adhesive: Using a piezoelectric valve dispensing system, precisely apply black encapsulating adhesive 5 to the step formed by the bending area 4 of the flexible circuit board (COF).

[0047] Step S4, Stepwise Curing: Use an LED-UV light source with a wavelength of 405nm to UV cure the black encapsulating adhesive 5 with an energy of 10000mJ / cm² until it is completely cured (the tensile strength of the black encapsulating adhesive 5 after curing is about 18MPa, and the curing depth is about 0.9mm).

[0048] Step S5, Edge Sealing Adhesive Application: After the black encapsulating adhesive 5 has fully cured, use the same piezoelectric valve dispensing system to precisely apply the black edge sealing adhesive 6 to the surface of the flexible circuit board (COF) bending area 4 and the gaps between components. The dispensing path is precisely programmed to ensure that the black edge sealing adhesive 6 completely covers all circuit parts that need to be shielded, and that its edges form a smooth, seamless transition with the edge of the upper optical film layer (POL film) 3.

[0049] Step S6, UV Curing: Using a 405nm LED-UV light source, the black edge-sealing adhesive 6 is UV-cured at an energy of 12000mJ / cm² to ensure complete curing (the tensile strength of the cured black edge-sealing adhesive 6 is approximately 18MPa, and the curing depth is approximately 0.6mm). After curing, the color difference ΔE between the adhesive and the optical film layer (POL film) 3 is approximately 1.5, indicating excellent light-blocking properties. The final product has a bottom bezel width of 3.0mm and has passed reliability tests including 1000 hours of high temperature and high humidity (60℃ / 90%RH) and 1000 hours of high and low temperature tests (-40℃ to 80℃ cycle test) (no cracking or peeling of the adhesive layer, stable bonding strength, and normal display panel function).

[0050] Example 2: A packaging structure for achieving a narrow bezel on all four sides of a display screen includes a display panel body. The display panel body comprises a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate. A flexible circuit board bending area is formed between the first substrate and the optical film layer. A functionalized adhesive encapsulation component is provided within the flexible circuit board bending area. The functionalized adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic bezels. The functionalized adhesive encapsulation component consists of the following two parts:

[0051] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0052] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0053] Both the black encapsulating adhesive and the black edge sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-blocking performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge sealing adhesive is used to construct a shaping edge sealing layer to prevent light leakage and water vapor penetration.

[0054] The functionalized adhesive encapsulation assembly reduces the width of the bottom bezel of the display from 15-20mm for traditional metal / plastic bezels to 2.8mm.

[0055] The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 33 parts flexible polyurethane acrylate resin, 12 parts vinyl fluorinated hyperbranched silicone resin, 2.3 parts photoinitiator, 43 parts reactive diluent, 0.2 parts antioxidant, 0.5 parts leveling agent, 0.4 parts coupling agent, 3.5 parts other functional monomers, and 0.3 parts black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-methylene)bis(methylene)diacrylate compounded in a mass ratio of 2:0.9:0.35; the flexible polyurethane acrylate resin is BASF Laromer UA. 9030; the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 in invention patent document CN119192582B; the photoinitiator is photoinitiator 369; the reactive diluent is 3,3,5-trimethylcyclohexyl acrylate; the antioxidant is Irganox 1135; the leveling agent is leveling agent TEGO 410; the coupling agent is silane coupling agent KH56; the black pigment is black pigment U4115.

[0056] A method for fabricating the above-mentioned encapsulation structure that achieves a narrow bezel on all four sides of the display screen, such as... Figure 3 The process includes the following steps: First, the border area is cleaned. Then, black encapsulating adhesive 5 and black edge-sealing adhesive 6 are sequentially applied using a piezoelectric valve dispensing system. After all adhesives have been applied, a single vertical irradiation curing process is performed using a 405nm LED-UV light source with an energy of 12000 mJ / cm². This solution reduces one production step and is suitable for automated production lines with higher efficiency requirements. The final product has a bottom border width of 2.8mm, the adhesive appearance is consistent with the optical film layer, and the performance is comparable to Example 1. It passed all reliability tests.

[0057] Example 3: A packaging structure for achieving a narrow bezel on all four sides of a display screen includes a display panel body. The display panel body comprises a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate. A flexible circuit board bending area is formed between the first substrate and the optical film layer. A functionalized adhesive encapsulation component is provided within the flexible circuit board bending area. The functionalized adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic bezels. The functionalized adhesive encapsulation component consists of the following two parts:

[0058] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0059] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0060] Both the black encapsulating adhesive and the black edge sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-blocking performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge sealing adhesive is used to construct a shaping edge sealing layer to prevent adhesive overflow and contamination.

[0061] The functionalized adhesive encapsulation assembly reduces the width of the bottom bezel of the display from 15-20mm for traditional metal / plastic bezels to 3mm.

[0062] The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 35 parts flexible polyurethane acrylate resin, 13 parts vinyl fluorinated hyperbranched silicone resin, 2.5 parts photoinitiator, 45 parts reactive diluent, 0.3 parts antioxidant, 0.6 parts leveling agent, 0.5 parts coupling agent, 4 parts other functional monomers, and 0.35 parts black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, (octahydro-4,7-methylene-1H-indene- The following components are used: 1,5-methylene (methylene) diacrylate is compounded in a mass ratio of 2:1:0.4; the flexible polyurethane acrylate resin is Sartoma CN9006NS; the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 in invention patent document CN119192582B; the photoinitiator is photoinitiator 651; the reactive diluent is 4-acryloylmorpholine; the antioxidant is Irgafos168; the leveling agent is leveling agent TEGO Glide100; the coupling agent is silane coupling agent KH570; and the black pigment is black pigment U4117.

[0063] A method for fabricating the above-mentioned encapsulation structure for achieving a narrow bezel on all four sides of a display screen includes the following steps:

[0064] Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 35 min at 27℃ and 650 rpm / min. Then, vacuum stir for 45 min at 1700 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained.

[0065] Step S2, Pre-treatment: Perform plasma cleaning treatment on the bending area of ​​the flexible circuit board to remove surface contaminants and impurities;

[0066] Step S3, Encapsulating Adhesive Dispensing: Using a piezoelectric valve dispensing system, black encapsulating adhesive is precisely dispensed into the steps and gaps of the flexible circuit board bending area to completely fill them and make them flush with the design reference plane of the second substrate.

[0067] Step S4, edge sealing adhesive application: Using a piezoelectric valve dispensing system, black edge sealing adhesive is precisely applied to the surface of the black encapsulating adhesive, the exposed structure in the bending area of ​​the flexible circuit board, and the gaps between components, so that it completely covers the exposed structure and seamlessly connects with the edge of the optical film layer.

[0068] Step S5, UV curing treatment: Vertical irradiation with an LED-UV light source with a wavelength of 405nm, curing energy ≥12000mJ / cm², to completely cure the black encapsulating adhesive and black edge sealing adhesive.

[0069] The piezoelectric valve dispensing system achieves precise control of adhesive volume by adjusting the air pressure parameter of 0.3MPa, the voltage output of 8V, and the working frequency of 120Hz, with a dispensing accuracy error of ≤±0.1mm. Between steps S3 and S4, there is also a step-by-step curing step, specifically: firstly, the black encapsulating adhesive is UV pre-cured with a curing energy of 12000mJ / cm² and a curing time of 30s.

[0070] Step S5 is followed by an appearance inspection step, which involves color difference detection of the cured functionalized adhesive encapsulation components to ensure that the color of the adhesive meets the standard of consistency with the optical film layer; at the same time, appearance defect detection is carried out to check for problems such as excess adhesive, insufficient adhesive, and air bubbles.

[0071] Example 4: A packaging structure for achieving a narrow bezel on all four sides of a display screen includes a display panel body. The display panel body comprises a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate. A flexible circuit board bending area is formed between the first substrate and the optical film layer. A functional adhesive encapsulation component is provided within the flexible circuit board bending area. The functional adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic bezels. The functional adhesive encapsulation component consists of the following two parts:

[0072] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0073] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0074] Both the black encapsulating adhesive and the black edge-sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-shielding performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge-sealing adhesive is used to construct a shaped edge-sealing layer to prevent adhesive overflow and contamination. The functionalized adhesive encapsulation component reduces the width of the bottom bezel of the display screen from 15-20mm of traditional metal / plastic bezels to 3mm.

[0075] The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 38 parts flexible polyurethane acrylate resin, 14 parts vinyl fluorinated hyperbranched silicone resin, 2.8 parts photoinitiator, 48 parts reactive diluent, 0.4 parts antioxidant, 0.9 parts leveling agent, 0.7 parts coupling agent, 4.5 parts other functional monomers, and 0.45 parts black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-ylidene)bis(methylene)diacrylate in the following mass ratios. The mixture is composed of a 2:1.1:0.45 ratio; the flexible polyurethane acrylate resin is Sartoma CN9006NS; the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 in invention patent document CN119192582B; the photoinitiator is photoinitiator 784; the reactive diluent is ethoxylated trimethylolpropane triacrylate; the antioxidant is Irgafos126; the leveling agent is leveling agent TEGO450; the coupling agent is silane coupling agent KH570; and the black pigment is black pigment D45.

[0076] A method for fabricating the above-mentioned encapsulation structure for achieving a narrow bezel on all four sides of a display screen includes the following steps:

[0077] Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 40 min at 28℃ and 700 rpm / min. Then, vacuum stir for 50 min at 1800 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained.

[0078] Step S2, Pre-treatment: Perform plasma cleaning treatment on the bending area of ​​the flexible circuit board to remove surface contaminants and impurities;

[0079] Step S3, Encapsulating Adhesive Dispensing: Using a piezoelectric valve dispensing system, black encapsulating adhesive is precisely dispensed into the steps and gaps of the flexible circuit board bending area to completely fill them and make them flush with the design reference plane of the second substrate.

[0080] Step S4, edge sealing adhesive application: Using a piezoelectric valve dispensing system, black edge sealing adhesive is precisely applied to the surface of the black encapsulating adhesive, the exposed structure in the bending area of ​​the flexible circuit board, and the gaps between components, so that it completely covers the exposed structure and seamlessly connects with the edge of the optical film layer.

[0081] Step S5, UV curing treatment: Vertical irradiation with an LED-UV light source with a wavelength of 405nm and a curing energy of 12000mJ / cm² is used to completely cure the black encapsulating adhesive and the black edge sealing adhesive.

[0082] The piezoelectric valve dispensing system achieves precise control of adhesive volume by adjusting the air pressure parameter of 0.35MPa, the voltage output of 9.5V, and the working frequency of 140Hz, with a dispensing accuracy error of ≤±0.1mm.

[0083] Between steps S3 and S4, there is also a step-by-step curing step, which is as follows: first, the black encapsulating adhesive is UV pre-cured with a curing energy of 10000mJ / cm² and a curing time of 40s; after step S5, there is also an appearance inspection step, which performs color difference detection on the cured functionalized adhesive encapsulation component to ensure that the color of the adhesive meets the standard of the optical film layer; at the same time, appearance defect detection is performed to check for problems such as excess adhesive, insufficient adhesive, and bubbles.

[0084] Example 5: A packaging structure for achieving a narrow bezel on all four sides of a display screen includes a display panel body. The display panel body comprises a first substrate, a second substrate, and an optical film layer attached to the surface of the second substrate. A flexible circuit board bending area is formed between the first substrate and the optical film layer. A functional adhesive encapsulation component is provided within the flexible circuit board bending area. The functional adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic bezels. The functional adhesive encapsulation component consists of the following two parts:

[0085] Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate.

[0086] Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure.

[0087] Both the black encapsulating adhesive and the black edge-sealing adhesive are UV-curable. After curing, their colors are consistent with the black of the optical film layer in its non-display state, satisfying a color difference ΔE≤2.0, and they have 100% light-shielding performance. The black encapsulating adhesive is used to fully penetrate and fill microscopic gaps. The black edge-sealing adhesive is used to construct a shaped edge-sealing layer to prevent light leakage and moisture penetration. The functionalized adhesive encapsulation component reduces the width of the bottom bezel of the display screen from 15-20mm of traditional metal / plastic bezels to 3mm.

[0088] The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 40 parts flexible polyurethane acrylate resin, 15 parts vinyl fluorinated hyperbranched silicone resin, 3 parts photoinitiator, 50 parts reactive diluent, 0.5 parts antioxidant, 1 part leveling agent, 0.8 parts coupling agent, 5 parts other functional monomers, and 0.5 parts black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-methylene)bis(methylene)diacrylate compounded in a mass ratio of 2:1.2:0.5; the flexible polyurethane acrylate resin is BASF Laromer UA. 9030; the vinyl fluorinated hyperbranched silicone resin is prepared according to the method of Example 1 in invention patent document CN119192582B; the photoinitiator is photoinitiator 907; the reactive diluent is isobornyl methacrylate; the antioxidant is Irgafos126; the leveling agent is leveling agent TEGO450; the coupling agent is silane coupling agent KH560; the black pigment is black pigment U4115.

[0089] A method for fabricating the above-mentioned encapsulation structure for achieving a narrow bezel on all four sides of a display screen includes the following steps:

[0090] Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 50 min at 30℃ and 800 rpm / min. Then, vacuum stir for 60 min at 2000 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained.

[0091] Step S2, Pre-treatment: Perform plasma cleaning treatment on the bending area of ​​the flexible circuit board to remove surface contaminants and impurities;

[0092] Step S3, Encapsulating Adhesive Dispensing: Using a piezoelectric valve dispensing system, black encapsulating adhesive is precisely dispensed into the steps and gaps of the flexible circuit board bending area to completely fill them and make them flush with the design reference plane of the second substrate.

[0093] Step S4, edge sealing adhesive application: Using a piezoelectric valve dispensing system, black edge sealing adhesive is precisely applied to the surface of the black encapsulating adhesive, the exposed structure in the bending area of ​​the flexible circuit board, and the gaps between components, so that it completely covers the exposed structure and seamlessly connects with the edge of the optical film layer.

[0094] Step S5, UV curing treatment: Vertical irradiation with an LED-UV light source with a wavelength of 405nm and a curing energy of 12000mJ / cm² is used to completely cure the black encapsulating adhesive and the black edge sealing adhesive.

[0095] The piezoelectric valve dispensing system achieves precise control of adhesive volume by adjusting the air pressure parameter of 0.4MPa, the voltage output of 10V, and the working frequency of 150Hz, with a dispensing accuracy error of ≤±0.1mm. Between steps S3 and S4, there is also a step-by-step curing step, specifically: first, the black encapsulating adhesive is UV pre-cured with a curing energy of 10000mJ / cm² and a curing time of 40s. After step S5, there is also an appearance inspection step, which performs color difference detection on the cured functionalized adhesive encapsulation component to ensure that the color of the adhesive meets the standard of the optical film layer; at the same time, appearance defect detection is performed to check for problems such as overflow, insufficient adhesive, and bubbles.

[0096] Comparative Example 1

[0097] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of flexible polyurethane acrylate resin is used instead of vinyl fluorinated hyperbranched silicone resin.

[0098] Comparative Example 2

[0099] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of vinyl fluorinated hyperbranched silicone resin is used instead of flexible polyurethane acrylate resin.

[0100] Comparative Example 3

[0101] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of bisphenol A epoxy acrylate is used instead of allyl-β-cyclodextrin.

[0102] Comparative Example 4

[0103] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of allyl-β-cyclodextrin is used instead of bisphenol A epoxy acrylate.

[0104] Comparative Example 5

[0105] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of (octahydro-4,7-methylene-1H-indene-1,5-methylene)bis(methylene)diacrylate is used instead of bisphenol A epoxy acrylate.

[0106] Comparative Example 6

[0107] This example provides a packaging structure and its preparation method for achieving a narrow bezel on all four sides of a display screen. It is basically the same as Example 5, except that an equal amount of bisphenol A epoxy acrylate is used instead of (octahydro-4,7-methylene-1H-indene-1,5-methylene)bis(methylene)diacrylate.

[0108] To further illustrate the beneficial technical effects of the black encapsulating adhesive and black edge sealing adhesive involved in the embodiments of this application, relevant performance tests were conducted on the black encapsulating adhesive and black edge sealing adhesive involved in Example 5 and Comparative Examples 1-6. The test results are shown in Table 1, and the test methods are as follows:

[0109] (1) Comparison of high temperature and high humidity resistance: The prepared adhesive was applied to the TFT substrate circuit using an automatic dispensing machine to form an adhesive strip with a length of 800 mm, a width of 4 mm, and a thickness of 0.5 mm. Then, it was cured with a 405 nm ultraviolet lamp at 12000 mJ / cm². 2 The circuit is cured under UV light for 60 seconds. After curing, the circuit coated with UV protective adhesive is placed in a high-temperature and high-humidity aging chamber at 60℃ / 90%RH. The corrosion of the circuit is observed, and the time when corrosion appears is recorded. Below 800h, the rating is ×; between 800h and 1500h, the rating is ○; and above 1500h, the rating is ◎.

[0110] (2) Comparison of reworkability: The prepared black adhesive was applied to the TFT substrate in strips 800 mm long, 4 mm wide, and 0.5 mm thick using an automatic dispensing machine, and then cured with a 405 nm UV lamp at 12000 mJ / cm². 2 The adhesive strip is cured under UV light for 60 seconds. After curing, the edge of the adhesive strip is lifted with tweezers and the strip is torn at a 90° angle to the substrate to see if it breaks. If the adhesive strip cannot be torn at an angle, it is rated as ×. If the adhesive strip breaks, it is rated as ▲. If the adhesive strip can be completely peeled off from the substrate, it is rated as ◎.

[0111] Table 1 Performance Test Results

[0112]

[0113] As shown in Table 1, the black encapsulating adhesive and black edge-sealing adhesive involved in Example 5 of this invention exhibit better high-temperature and high-humidity resistance and repairability compared to the comparative example. The combined use of vinyl fluorinated hyperbranched silicone resin, flexible polyurethane acrylate resin, (octahydro-4,7-methylene-1H-inden-1,5-methylene)bis(methylene)diacrylate, bisphenol A epoxy acrylate, and allyl-β-cyclodextrin has a positive effect on improving the above-mentioned effects.

[0114] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A packaging structure for achieving a narrow bezel on all four sides of a display screen, characterized in that, The device includes a display panel body, which comprises a first substrate, a second substrate, and an optical film layer adhered to the surface of the second substrate. A flexible circuit board bending region is formed between the first substrate and the optical film layer. A functional adhesive encapsulation component is provided within the flexible circuit board bending region. The functional adhesive encapsulation component replaces the protective, shielding, and structural support functions of traditional metal or plastic frames. The functional adhesive encapsulation component consists of the following two parts: Black encapsulating adhesive is used to fill the gaps and stepped structures in the bending area of ​​the flexible circuit board, with its top filling surface flush with the design reference plane of the second substrate. Black edge sealing adhesive is applied to the outer surface of the black encapsulating adhesive, the component gaps in the bending area of ​​the flexible circuit board, and extends to the edge of the optical film layer, forming a visually seamless connection structure. The independent formulations of the black encapsulating adhesive and the black edge sealing adhesive, by weight, are as follows: 30-40 parts of flexible polyurethane acrylate resin, 10-15 parts of vinyl fluorinated hyperbranched silicone resin, 2-3 parts of photoinitiator, 40-50 parts of reactive diluent, 0.1-0.5 parts of antioxidant, 0.3-1 parts of leveling agent, 0.3-0.8 parts of coupling agent, 3-5 parts of other functional monomers, and 0.2-0.5 parts of black pigment; the other functional monomers are bisphenol A epoxy acrylate, allyl-β-cyclodextrin, and (octahydro-4,7-methylene-1H-inden-1,5-ylidene)bis(methylene)diacrylate compounded in a mass ratio of 2:(0.8-1.2):(0.3-0.5).

2. The packaging structure for achieving a narrow bezel on all four sides of the display screen according to claim 1, characterized in that, The first substrate is a TFT substrate; the second substrate is a CF substrate or encapsulation glass; the optical film is a POL film; both the black encapsulating adhesive and the black edge sealing adhesive are UV-curable, and after curing, their colors are consistent with the black of the optical film in its non-display state, satisfying a color difference ΔE≤2.0, and possessing 100% light-shielding performance; the black encapsulating adhesive is used to fully penetrate and fill microscopic gaps; the black edge sealing adhesive is used to construct a shaping edge sealing layer to prevent light leakage and moisture penetration; the functionalized adhesive encapsulation component reduces the width of the bottom bezel of the display screen to less than 5mm.

3. The packaging structure for achieving a narrow bezel on all four sides of the display screen according to claim 1, characterized in that, The flexible polyurethane acrylate resin is one or more of Evonik EBECRIL® 270, BASF Laromer UA 9030, and Sartoma CN9006NS; the photoinitiator is at least one of photoinitiator 184, photoinitiator 369, photoinitiator 651, photoinitiator 784, photoinitiator 819, photoinitiator 907, photoinitiator 1173, and photoinitiator 2959; the reactive diluent is one or any mixture of isobornyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 4-acryloylmorpholine, and ethoxylated trimethylolpropane triacrylate; and the antioxidant is at least one of Irganox 1010, Irganox 1135, Irgafos 168, and Irgafos 126.

4. The packaging structure for achieving a narrow bezel on all four sides of the display screen according to claim 1, characterized in that, The leveling agent is at least one of leveling agent TEGO450, leveling agent TEGO410, and leveling agent TEGO Glide100; the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570; the black pigment is one or any mixture of black pigment D45, black pigment U4115, and black pigment U4117.

5. A method for fabricating a packaging structure with narrow bezels on all four sides of a display screen as described in any one of claims 1-4, characterized in that, Includes the following steps: Step S1, Adhesive compounding: Prepare black encapsulating adhesive and black edge sealing adhesive separately. Weigh each component according to the corresponding formula ratio and add them to the mixing tank in sequence. Vacuum stir for 30-50 min at 25-30℃ and 600-800 rpm / min. Then, vacuum stir for 40-60 min at 1500-2000 rpm / min until the mixture is uniform and there is no obvious particle feel. After centrifugation and degassing treatment, uniform black encapsulating adhesive and black edge sealing adhesive without bubbles are obtained. Step S2, Pre-treatment: Perform plasma cleaning treatment on the bending area of ​​the flexible circuit board to remove surface contaminants and impurities; Step S3, Encapsulating Adhesive Dispensing: Using a piezoelectric valve dispensing system, black encapsulating adhesive is precisely dispensed into the steps and gaps of the flexible circuit board bending area to completely fill them and make them flush with the design reference plane of the second substrate. Step S4, edge sealing adhesive application: Using a piezoelectric valve dispensing system, black edge sealing adhesive is precisely applied to the surface of the black encapsulating adhesive, the exposed structure in the bending area of ​​the flexible circuit board, and the gaps between components, so that it completely covers the exposed structure and seamlessly connects with the edge of the optical film layer. Step S5, UV curing treatment: Vertical irradiation with a 405nm wavelength LED-UV light source, curing energy ≥10000mJ / cm². 2 This allows the black encapsulating adhesive and black edge sealing adhesive to fully cure.

6. The method for fabricating a packaging structure with narrow bezels on all four sides of a display screen according to claim 5, characterized in that, The piezoelectric valve dispensing system achieves precise control of adhesive volume by adjusting the air pressure parameters (0.2-0.4MPa), voltage output (6-10V), and operating frequency (80-150Hz), with a dispensing accuracy error of ≤±0.1mm.

7. The method for fabricating a packaging structure with narrow bezels on all four sides of a display screen according to claim 5, characterized in that, Between steps S3 and S4, there is also a step-by-step curing step, specifically: first, the black encapsulating adhesive is UV cured with a curing energy of 10000-12000 mJ / cm. 2 The curing time is 30-40 seconds.

8. The method for fabricating a packaging structure with narrow bezels on all four sides of a display screen according to claim 5, characterized in that, Step S5 is followed by an appearance inspection step, which specifically involves: color difference detection of the cured functionalized adhesive encapsulation components to ensure that the color of the adhesive meets the standard of consistency with the optical film layer; and appearance defect detection to check for issues such as excess adhesive, insufficient adhesive, and air bubbles.

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