Display module and manufacturing method thereof, and flexible display device
Patent Information
- Application Number
- CN202510570391.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2026-10-30
AI Technical Summary
[0002]目前，市场上柔性显示屏还都是通过POL(Polarizer，偏光层)来阻挡外界的反射光问题，在全面屏趋势下，POL与AA(Active Area，有效显示区域)间隙逐渐减少，高低温实验时又因POL会有热胀冷缩的特性，当POL与屏体表面贴附剥离力较大时，容易拉扯到屏体封装层TFE(Thin Film Encapsulation，薄膜封装)，造成OLED(Organic Light-EmittingDiode，有机发光二极管)屏的封装层失效，从而靠近AA边缘产生黑斑等问题
[0028]本申请提供的一种防屏体黑斑的显示模组有益效果在于：与现有技术相比，本申请由于在薄膜封装层的外围封装部涂布有由低表面能材料制成的低表面能材料层，该低表面能材料层的上表面与偏光层面向低表面能材料层的表面进行低表面能的粘接。这样，该低表面能材料层与偏光层在该处的粘着力就会下降，从何使得偏光层在热胀冷缩时对其下方的薄膜封装层的拉扯力就会显著下降，进而使得该处的薄膜封装层不易受拉扯而破损，其封装的有机层自然也不会暴露在外，也就避免了在靠近显示区域边缘的区域产生黑斑等显示不良问题。
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Figure CN123016828A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of display panel manufacturing technology, and more specifically, relates to a display module and manufacturing method for preventing black spots on the screen, and a flexible display screen. Background Technology
[0002] Currently, flexible displays on the market rely on a polarizer (POL) to block reflected light. However, with the trend towards full-screen displays, the gap between the POL and the active area (AA) is gradually decreasing. Furthermore, due to the thermal expansion and contraction of the POL during high and low temperature tests, significant peel force between the POL and the screen surface can easily tear the thin film encapsulation (TFE) layer, causing the OLED (Organic Light-Emitting Diode) screen's encapsulation layer to fail, resulting in black spots near the AA edge. Therefore, solving the problem of TFE damage caused by POL thermal expansion and contraction has become an urgent issue for the industry. Summary of the Invention
[0003] The purpose of this application is to provide a display module that prevents black spots on the screen, so as to solve the above-mentioned technical problems existing in the prior art.
[0004] To achieve the above objectives, the technical solution adopted in this application is: a display module for preventing black spots on the screen, the display module for preventing black spots on the screen comprising:
[0005] A flexible display screen has a light-emitting surface and defines a display area and a non-display area surrounding the display area.
[0006] The thin-film encapsulation layer is located on the light-emitting surface. The thin-film encapsulation layer includes a display encapsulation part and a peripheral encapsulation part. The peripheral encapsulation part is located around the display encapsulation part and is connected to the display encapsulation part. The display encapsulation part is located at the corresponding position in the display area, and the peripheral encapsulation part is located at the corresponding position in the non-display area.
[0007] A polarizing layer is disposed on the side of the thin film encapsulation layer away from the light-emitting surface. The polarizing layer covers the display encapsulation part and extends to the side of the peripheral encapsulation part away from the light-emitting surface.
[0008] A low surface energy material layer is located between the thin film encapsulation layer and the polarizing layer. The low surface energy material layer has a low surface energy bonding surface facing the polarizing layer, and the low surface energy bonding surface is bonded to the surface of the polarizing layer facing the low surface energy material layer with low surface energy.
[0009] In this case, the edge of the orthographic projection of the polarizing layer on the light-emitting surface is located within the orthographic projection of the low surface energy material layer on the light-emitting surface.
[0010] Optionally, a low surface energy material layer is patterned and coated on a portion of the outer packaging portion.
[0011] Optionally, the outer edge of the peripheral encapsulation portion protrudes beyond the outer edge of the polarizing layer, one end of the low surface energy material layer extends to be flush with the outer edge of the peripheral encapsulation portion, and the other end of the low surface energy material layer extends to the junction of the display encapsulation portion and the peripheral encapsulation portion.
[0012] Optionally, the low surface energy material layer is made of a fluorine-containing low surface energy material.
[0013] Optionally, the low surface energy material layer is a high surface roughness layer, which is formed by coating a portion of the outer packaging portion with a high surface roughness material.
[0014] Optionally, the low surface energy bonding surface of the high surface roughness layer has a peak facing the polarizing layer and a trough opposite to the peak. The roughness of the high surface roughness material is represented by the difference between the peak and the trough, and the difference between the peak and the trough is greater than or equal to the thickness of the polarizing layer.
[0015] This application also proposes a method for manufacturing a display module with anti-screen black spots. This method is used to manufacture the display module with anti-screen black spots as described above, and the method includes the following steps:
[0016] The light-emitting surface of the flexible display to be packaged is subjected to thin-film encapsulation treatment to form a thin-film encapsulation layer in the display area and the non-display area;
[0017] A low surface energy material layer is formed by patterning and coating a low surface energy material on the peripheral encapsulation portion of the thin film encapsulation layer.
[0018] The polarizing layer is attached above the thin-film encapsulation layer and the low surface energy material layer.
[0019] Optionally, the step of patterning and coating a low surface energy material onto the peripheral encapsulation portion of the thin-film encapsulation layer to form a low surface energy material layer includes the following sub-steps:
[0020] A pattern of a pre-defined low surface energy material layer is formed on a printing screen;
[0021] The printing screen is placed above the film encapsulation layer. The pattern of the low surface energy material layer corresponds one-to-one with the position of the coating area on the film encapsulation layer. The printing paste made of low surface energy material is used to print the pattern onto the coating area.
[0022] The low surface energy material layer is formed by drying and curing the pattern of the printed low surface energy material layer.
[0023] Optionally, the step of attaching the polarizing layer over the thin-film encapsulation layer and the low surface energy material layer includes the following sub-steps:
[0024] The flexible polarizer is pretreated, and a flexible transparent optical adhesive is coated on the lower surface of the flexible polarizer facing the thin film encapsulation layer.
[0025] A pre-treated flexible polarizer is vacuum-bonded onto a thin film encapsulation layer and a low surface energy material layer using a fully automatic laminating machine to form a polarizing layer; the outer edges of the thin film encapsulation layer and the low surface energy material layer both protrude from the outer edge of the polarizing layer.
[0026] The polarizing layer undergoes subsequent curing and defoaming treatment.
[0027] This application also proposes a flexible display device, including a display module as described above that prevents black spots on the screen.
[0028] The beneficial effects of the display module for preventing black spots on the screen provided in this application are as follows: Compared with the prior art, this application coats a low surface energy material layer made of a low surface energy material on the outer packaging portion of the thin film encapsulation layer. The upper surface of this low surface energy material layer is bonded to the polarizing layer with a low surface energy. In this way, the adhesion between the low surface energy material layer and the polarizing layer at this location is reduced, thereby significantly reducing the tensile force of the polarizing layer on the underlying thin film encapsulation layer during thermal expansion and contraction. Consequently, the thin film encapsulation layer at this location is less prone to tearing due to tension, and its encapsulated organic layer is not exposed, thus avoiding display defects such as black spots near the edge of the display area. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 A simplified cross-sectional diagram of a display module in existing technology that is prone to black spots on the screen.
[0031] Figure 2 A simplified cross-sectional view of a display module for preventing black spots on the screen provided in one embodiment of this application;
[0032] Figure 3 for Figure 2 Enlarged view of point A in the middle;
[0033] Figure 4 A partial cross-sectional structural diagram of a display module for preventing black spots on the screen provided in another embodiment of this application;
[0034] Figure 5 for Figure 4 Enlarged view of point B in the middle;
[0035] Figure 6 A flowchart illustrating a method for manufacturing a display module that prevents black spots on the screen, as provided in an embodiment of this application.
[0036] Explanation of icon numbers:
[0037] label name label name 100 Display area 200 Thin film encapsulation layer 300 Low surface energy material layer 110 Dark spots 400 polarizing layer 510 BPF layer 520 BPL layer 530 OCA layer 540 CG lnk layer 550 CG layer Detailed Implementation
[0038] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.
[0039] It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "Multiple" means two or more, unless otherwise explicitly specified. Therefore, they should not be construed as limitations on this application.
[0040] This application provides a display module for preventing black spots on the screen and a method for manufacturing the same.
[0041] Please see Figure 2 and Figure 3In one embodiment, the display module of the anti-screen black spot 110 includes a flexible display screen with a light-emitting surface, defining a display area 100 and a non-display area surrounding the display area 100. Specifically, the anti-screen black spot display module includes the following functional film layers, from bottom to top: a thin-film encapsulation layer 200, a low surface energy material layer 300, and a polarizing layer 400. The thin-film encapsulation layer 200 is located on the light-emitting surface and includes a display encapsulation part and a peripheral encapsulation part. The peripheral encapsulation part is located around and connected to the display encapsulation part, with the display encapsulation part located at a corresponding position in the display area 100 and the peripheral encapsulation part located at a corresponding position in the non-display area. The polarizing layer 400 is located on the side of the thin-film encapsulation layer 200 away from the light-emitting surface, covering the display encapsulation part and extending to the side of the peripheral encapsulation part away from the light-emitting surface. A portion of the low surface energy material layer 300 is located between the thin film encapsulation layer 200 and the polarizing layer 400. The low surface energy material layer 300 has a low surface energy bonding surface facing the polarizing layer 400, and the low surface energy bonding surface is bonded to the surface of the polarizing layer 400 facing the low surface energy material layer 300 with low surface energy. The edge of the orthographic projection of the polarizing layer 400 on the light-emitting surface lies within the orthographic projection of the low surface energy material layer 300 on the light-emitting surface.
[0042] In commonly used flexible displays, a polarizing layer 400 is typically placed on the thin-film encapsulation layer 200 to address the issue of reflected light. This polarizing layer 400 is usually formed by bonding a flexible substrate coated with a polarizing film to the thin-film encapsulation layer 200 using flexible transparent optical adhesive. It reduces screen reflectivity, improves display contrast, and blocks reflected light. However, after the flexible display is manufactured, numerous performance tests are required, one of which is a thermal cycling test. In this test, the polarizing layer 400 is continuously subjected to high and low temperature cycling environments, specifically as follows... Figure 1 As shown, due to the thermal expansion and contraction characteristics of its material in high and low temperature environments, when the peeling force between the polarizing layer 400 and the screen surface is large, it is easy to pull the thin film encapsulation layer 200 below it, causing the encapsulation to break at that point, which in turn causes the organic layer to be exposed, resulting in display defects such as black spots 110 appearing near the edge of the display area 100.
[0043] To address this technical problem, based on the aforementioned display module design for preventing black spots on the screen, in this embodiment, a low surface energy material layer 300 made of a low surface energy material is coated on the outer packaging portion of the thin-film encapsulation layer 200. The upper surface of this low surface energy material layer 300 is bonded to the surface of the polarizing layer 400 facing the low surface energy material layer with low surface energy. This reduces the adhesion between the low surface energy material layer 300 and the polarizing layer 400 at that location, significantly reducing the tensile force exerted by the polarizing layer 400 on the underlying thin-film encapsulation layer 200 during thermal expansion and contraction. Consequently, the thin-film encapsulation layer 200 is less prone to tearing due to tension, and its encapsulated organic layer is not exposed, thus avoiding display defects such as black spots 110 near the edge of the display area 100.
[0044] It should be noted that low surface energy materials refer to materials with low surface energy, where the intermolecular forces are weak, making it difficult for liquids to spread and wet their surfaces. These materials typically possess hydrophobic, antifouling, and anti-adhesion properties. The technical solution of this application utilizes the anti-adhesion properties of low surface energy materials to effectively prevent the adhesion of materials such as colloids. Here, the surface energy optimization treatment is actually performed on the area above the peripheral encapsulation layer adjacent to the display encapsulation section. This optimization method includes, but is not limited to, reducing the contact between the polarizing layer 400 and the thin-film encapsulation layer 200 in this area, increasing the low surface energy, and using a stretchable low-modulus material layer. Here, the display area 100 in a flexible display screen must possess bendability and deformation resistance, while maintaining high resolution, color uniformity, and stability. It typically includes key structures such as driving circuits (e.g., TFT arrays) and light-emitting layers (e.g., OLED pixels). Non-AA areas, i.e., non-display areas, are typically used for wiring or encapsulation and do not participate in the display. Because the organic light-emitting layer of a flexible OLED screen is highly sensitive to water and oxygen intrusion, the encapsulation of the AA area, i.e., the display area 100, requires special protection against water and oxygen intrusion and must withstand repeated bending. Therefore, the technical solution of this application employs thin-film encapsulation technology, with a thin-film encapsulation layer 200 covering the display area 100 to protect it from external environmental corrosion. The thin-film encapsulation layer 200 in this application is a protective layer formed using thin-film encapsulation technology. Thin-film encapsulation technology is a core encapsulation technology for flexible displays, especially flexible OLED displays, to protect the light-emitting materials from water and oxygen corrosion. It encapsulates the display by depositing an ultra-thin inorganic / organic composite film layer to replace the glass or metal cover used in traditional rigid screens, giving the display flexibility. It typically employs a multi-layer alternating stacked structure, combining the advantages of inorganic and organic layers. The inorganic layer provides ultra-high barrier properties to prevent water and oxygen from corroding the OLED organic materials, while the organic layer absorbs bending stress, preventing the inorganic layer from becoming brittle, allowing the display to be repeatedly bent or folded.
[0045] Please see Figure 2 and Figure 3 One embodiment shown, and Figure 4 and Figure 5 In another embodiment shown, in both embodiments, the low surface energy material layer 300 is patterned and coated on a portion of the peripheral encapsulation portion. These localized areas of the peripheral encapsulation portion coated with the low surface energy material layer 300 pattern are called coating areas. It is understood that since the low surface energy material layer 300 possesses certain anti-adhesion properties, it is preferable to perform localized coating on the peripheral encapsulation portion. In other words, in the area adjacent to the display encapsulation portion of the peripheral encapsulation portion, multiple coating areas are preferably distributed at intervals and preferably located in areas that do not affect the display or wiring. Here, patterned coating of the low surface energy material layer 300 means that the coating shape of the low surface energy material layer 300 is patterned. For example, the coating pattern can be, but is not limited to, rectangles, squares, triangles, circles, ellipses, irregular polygons, or irregular patterns. In the same flexible display, these coating patterns can be consistent or inconsistent. For example, in one embodiment, all coating patterns can be the same; for example, all coating patterns can be one of rectangles, squares, triangles, circles, ellipses, irregular polygons, or irregular patterns. For example, in another embodiment, all the coating patterns can be different. For example, in some coating areas, the coating pattern is circular, in other coating areas, the coating pattern is rectangular, and in still other coating areas, the coating pattern is an irregular polygon. The position and specific shape of the pattern can be adjusted according to the actual situation, and no special restrictions are imposed here.
[0046] Specifically, as in Figure 2 and Figure 3 One embodiment shown, and Figure 4 and Figure 5 In another embodiment shown, the outer edge of the thin-film encapsulation layer 200 protrudes beyond the outer edge of the polarizing layer 400. One end of the low surface energy material layer 300 extends to be flush with the outer edge of the peripheral encapsulation portion, and the other end extends to the junction of the display encapsulation portion and the peripheral encapsulation portion. It can be understood that the outer edge of the peripheral encapsulation portion is longer than the outer edge of the polarizing layer 400 because, in a flexible display screen, the organic light-emitting layer of the display area 100 is highly sensitive to water and oxygen intrusion. A wider and longer outer edge of the peripheral encapsulation portion provides better protection for the display area 100. Of course, shortening the outer edge of the polarizing layer 400 facilitates its connection with the bent BPL (Barrier Protective Layer). In other embodiments, the outer edge of the polarizing layer 400 may also be flush with the outer edges of the low surface energy material layer 300 and the thin-film encapsulation layer 200.
[0047] In such Figure 2 and Figure 3In one embodiment, the low surface energy material layer 300 is made of a fluorinated low surface energy material. In this embodiment, the fluorinated low surface energy material is a fluorinated liquid, such as, but not limited to, fluorocarbon compounds. Adding a local fluorinated liquid layer below the polarizing layer 400 prevents the edge adhesive of the polarizing layer 400 from stacking on top of the thin-film encapsulation layer 200. During thermal expansion and contraction, it reduces the tensile stress in the X direction, thereby preventing damage to the encapsulated film layer. Of course, in other embodiments, other low surface energy materials can be used, such as materials containing low-polarity groups like silicon (-Si-O-) and long-chain alkyl (-CH3). It is understood that the fluorinated low surface energy material introduces the low-polarity fluorine (-F) group, thereby reducing intermolecular forces and achieving the effect of reducing the surface energy of the material. Fluorocarbon compounds, in particular, have low CF bond polarity and high bond energy, providing extremely low surface energy and chemical stability. In addition, in this embodiment, the fluorinated liquid not only reduces adhesion but also protects the thin film encapsulation layer 200, which can isolate the potassium ions deposited on the polarizing layer 400 from the screen body and prevent chemical corrosion of the flexible display screen.
[0048] In such Figure 4 and Figure 5In another embodiment shown, the low surface energy material layer 300 is a high surface roughness layer, formed by coating a portion of the outer packaging portion of the thin film encapsulation layer 200 with the high surface roughness material. It can be understood that adding a high surface roughness layer to the coating area reduces the adhesion between the adhesive surface of the polarizing layer 400 and the material, thereby significantly reducing the stress on the thin film encapsulation layer 200 during pulling, and making the film layer of the thin film encapsulation layer 200 less prone to damage. In other words, by setting the high surface roughness layer, it forms point contact with the adhesive surface of the polarizing layer 400 above the thin film encapsulation layer 200, thus also reducing the tensile stress of the polarizing layer 400 during thermal expansion and contraction. In this embodiment, the use of a high surface roughness material, compared to the use of a fluorinated liquid in the previous embodiment, has the advantages of easier material selection, preventing poor adhesion caused by the low surface energy fluorinated liquid overflowing to other locations, and allowing adjustment of the roughness ratio according to the effect. Here, the high-roughness layer is also patterned, and the coating pattern can be, but is not limited to, rectangles, squares, triangles, circles, ellipses, irregular polygons, or irregular patterns. Furthermore, these coating patterns can be consistent or inconsistent within the same flexible display screen. For example, in one embodiment, all coating patterns can be the same, one of the aforementioned patterns, while in another embodiment, all coating patterns can be different. For instance, in some coating areas, the coating pattern is one pattern, while in other coating areas, it is another pattern. There can be two or more types of coating patterns, and their placement and specific pattern shapes can be adjusted according to actual conditions, without particular limitation. Of course, since there are various choices of high-roughness materials, in different embodiments, different high-roughness materials for different patterns can be selected according to actual needs. For example, some coating patterns use one high-roughness material, while others use another.
[0049] Furthermore, such as Figure 5 As shown, the low surface energy bonding surface of the high-roughness layer has a peak facing the polarizing layer 400 and a trough opposite to the peak. The roughness of the high-roughness material is represented by the difference between the peak and the trough, and this difference is greater than or equal to the thickness of the polarizing layer 400. This results in better tensile strength. For example, in... Figure 4 and Figure 5 In the embodiment shown, the adhesive film thickness of the polarizing layer 400 is 10 micrometers, and the roughness of the surface high-roughness material, i.e., the difference between the peaks and troughs, is preferably greater than 10 micrometers.
[0050] This application also proposes a method for manufacturing a display module with anti-screen black spots, which is used to manufacture the anti-screen black spot display module as described above. Figure 6 As shown, the manufacturing method of this anti-black-spot display module includes the following steps:
[0051] S1. Perform thin film encapsulation on the light-emitting surface of the flexible display screen to be encapsulated, so as to form a thin film encapsulation layer 200 in the display area 100 and the non-display area.
[0052] S2. A low surface energy material layer 300 is formed by patterning and coating a low surface energy material on the peripheral encapsulation portion of the thin film encapsulation layer 200.
[0053] S3. Attach the polarizing layer 400 on top of the thin film encapsulation layer 200 and the low surface energy material layer 300.
[0054] Based on this design, by coating the outer packaging portion with a low surface energy material to form a low surface energy material layer 300, the adhesion between the low surface energy material layer 300 and the polarizing layer 400 at that location will be reduced. In this way, the tensile force of the polarizing layer 400 on the underlying thin film packaging layer 200 will be significantly reduced when the polarizing layer 400 expands and contracts with temperature, and the thin film packaging layer 200 at that location will not be damaged. This effectively avoids the problem of organic layer exposure caused by packaging damage, and naturally avoids display defects such as black spots 110 in the area near the edge of the display area 100.
[0055] Specifically, the manufacturing method of the display module with anti-black spot effect mainly includes three steps: thin-film encapsulation, coating with low surface energy material, and attaching polarizing layer 400. For thin-film encapsulation, a multi-layer alternating stacked structure is preferred. This combines the advantages of inorganic and organic layers. For example, the inorganic layer provides ultra-high barrier properties, effectively isolating water and oxygen, while the organic layer absorbs bending stress, preventing the inorganic layer from becoming brittle and allowing the flexible display to maintain its flexibility. The synergistic effect of this multi-layer structure ensures that even if a micro-crack occurs in one layer, the other layers can still maintain the overall encapsulation effect. Furthermore, the thickness of the thin-film encapsulation layer 200 is only a few micrometers, and this thin and light design helps the flexible display achieve an ultra-thin form. For coating with low surface energy material, a patterned coating scheme is used. This patterned coating scheme is applicable to printing coating processes and is more suitable for large-scale industrial production, thus helping to reduce the production cost of flexible displays. For the attached polarizing layer 400, after coating with a low surface energy material, not only can the polarizing layer 400 block reflected light from the outside, but the low surface energy material layer 300 also reduces the adhesion between the low surface energy material layer 300 and the polarizing layer 400 on the outer packaging part near the display packaging part, thereby achieving the aforementioned technical objective of reducing the pulling force on the thin film packaging layer 200, and thus avoiding display defects such as black spots 110 in the area near the edge of the display area 100.
[0056] Furthermore, the step of patterning and coating a low surface energy material onto the peripheral encapsulation portion of the thin-film encapsulation layer 200 to form a low surface energy material layer 300 includes the following sub-steps:
[0057] A pre-defined pattern of a low surface energy material layer 300 is formed on a printing screen;
[0058] The printing screen is placed above the thin film encapsulation layer 200. The pattern of the low surface energy material layer 300 corresponds one-to-one with the position of the coating area on the thin film encapsulation layer 200. The printing paste made of the low surface energy material is used to print the pattern onto the coating area.
[0059] The low surface energy material layer 300 is formed by drying and curing the pattern of the printed low surface energy material layer 300.
[0060] In other words, the above-mentioned process for coating low surface energy materials employs screen printing. Specifically, firstly, the flexible display screen, which has already undergone thin-film encapsulation, needs to be surface-treated using methods such as plasma cleaning to remove surface contaminants. Then, a suitable type of printing screen is selected, such as, but not limited to, stainless steel or polyester screens, with the mesh count chosen based on the pattern precision. Next, the desired pattern is formed on the screen using photolithography or laser engraving, and the tension of the printing screen must be controlled to ensure uniform tension and prevent deformation during printing. Then, the printing paste is prepared according to requirements, and the ink viscosity needs to be adjusted to ensure leveling and resolution. During the screen printing process, a fully automatic high-precision screen printing machine equipped with a CCD alignment system is preferred. Through alignment, squeegeeing, and demolding processes, the printing paste, formulated with low surface energy materials, is accurately printed and coated onto the coating area. After printing and coating, drying and curing are required. For flexible displays, a low-temperature curing process with a curing temperature of less than 150 degrees Celsius is preferred to avoid thermal damage to the substrate.
[0061] Here, in such Figure 2 and Figure 3In one embodiment shown, since the low surface energy material layer 300 is made of a fluorinated low surface energy material, the printing paste is a liquid paste containing the fluorinated low surface energy material. Here, the pattern and placement of the low surface energy material layer 300 formed on the printing screen should be designed according to the actual situation. The number of patterns is usually multiple, and their types can be one or more. Furthermore, within the same printing screen, the types of patterns can be consistent or inconsistent. For example, in one embodiment, all printed patterns are circles, and these circles can be the same size. In another embodiment, all printed patterns are also circles, but these circles are of different sizes. In yet another embodiment, some printed patterns are circles of the same size, while other printed patterns are rectangles of the same size. In yet another embodiment, some printed patterns are circles of different sizes, while other printed patterns are rectangles of different sizes.
[0062] However, this design is not limited to this; in cases such as Figure 4 and Figure 5 In one embodiment shown, since the low surface energy material layer 300 is made of a high roughness material, the printing paste is a liquid paste containing the high roughness material. Similarly, the pattern and placement of the low surface energy material layer 300 formed on the printing screen should be designed according to the actual situation. The number of patterns is usually multiple, and the types can be one or more. Moreover, on the same printing screen, the types and sizes of these patterns can be consistent or inconsistent.
[0063] Furthermore, the step of attaching the polarizing layer 400 onto the thin-film encapsulation layer 200 and the low surface energy material layer 300 includes the following sub-steps:
[0064] The flexible polarizer is pretreated, and a flexible transparent optical adhesive is coated on the lower surface of the flexible polarizer facing the thin film encapsulation layer 200.
[0065] A pre-treated flexible polarizer is vacuum-bonded onto the thin film encapsulation layer 200 and the low surface energy material layer 300 using a fully automatic laminating machine to form a polarizing layer 400; the outer edges of the thin film encapsulation layer 200 and the low surface energy material layer 300 both protrude beyond the outer edge of the polarizing layer 400.
[0066] The polarizing layer 400 undergoes subsequent curing and defoaming treatment.
[0067] Here, the process of attaching the flexible polarizer to the thin-film encapsulation layer 200 in the flexible display screen is a key step in the manufacturing of flexible display devices. It is crucial to ensure high-precision bonding, no air bubbles, no stress residue, and to avoid damage to the thin-film encapsulation layer 200. Specifically, the flexible polarizer must first undergo pretreatment, including coating its surface with an anti-reflective or anti-fingerprint coating to improve optical performance. The edges of the flexible polarizer also need to be pre-cut (laser or die-cutting) to prevent edge lifting after bonding. Alternatively, the thin-film encapsulation layer 200 can undergo cleaning pretreatment such as plasma cleaning to remove surface contaminants. Then, a high-precision fully automated bonding machine is used to vacuum-bond the flexible polarizer onto the thin-film encapsulation layer 200 and the low surface energy material layer 300 to form the polarizing layer 400. During this process, a CCD camera can identify alignment marks on the thin-film encapsulation layer 200 and match them with marks on the flexible polarizer to ensure accurate bonding position. In this embodiment, the flexible polarizer is bonded using vacuum lamination. The lamination pressure is preferably 0.1-0.5 MPa, and a step-by-step pressure application is preferred. The lamination temperature is 25-40°C to avoid thermal expansion mismatch between the thin film encapsulation layer 200 and the polarizing layer 400 caused by high temperature. After successful lamination, the polarizing layer 400 requires subsequent curing and debubbling treatment. Curing includes, but is not limited to, ultraviolet curing or hot-press curing. Debubbling treatment can be performed using an autoclave to eliminate microbubbles.
[0068] This application also proposes a flexible display device, including a display module for preventing black spots on the screen as described above. The display module includes a flexible display screen, which includes a display area 100 and a non-display area. The non-display area surrounds the display area 100, meaning the inner edge of the non-display area 100 connects to the outer edge of the display area 100. The display area 100 is commonly referred to in the industry as the AA (Active Area), which is the area in the flexible display screen actually used to display images. The non-display area 100 typically includes the bezel area of the flexible display screen and is usually used for wiring or encapsulation, not for display. Conventional flat panel displays typically use glass or resin encapsulation, eliminating the need to consider deformation stress. However, in flexible displays, the display area 100 must balance high image quality, flexibility, and reliability. Furthermore, the organic light-emitting layer of the display area 100 in flexible displays is extremely sensitive to water and oxygen; for example, ppm-level water and oxygen can cause the organic light-emitting layer to fail. Therefore, thin-film encapsulation technology is typically used in flexible displays. In this thin-film encapsulation technology, the screen can be encapsulated by accumulating an ultra-thin inorganic / organic composite film layer, thereby giving the display screen flexibility. A polarizing layer 400 is then attached to the thin-film encapsulation layer 200. However, during the performance testing of the flexible display screen after its fabrication, especially during thermal cycling tests, the polarizing material used in the polarizing layer 400 exhibits thermal expansion and contraction characteristics at high or low temperatures. Therefore, when the polarizing layer 400 experiences significant peel force on the screen surface due to thermal expansion and contraction, it can easily pull on the underlying thin-film encapsulation, potentially causing the encapsulation layer to fail at that location. This can result in display defects such as black spots 110 near the outer edge of the display area 100. In the technical solution of this application, as mentioned above, since a low surface energy material layer 300 is provided at the peripheral encapsulation part below the polarizing layer 400, the adhesion between the adhesive surface of the polarizing layer 400 and the low surface energy material layer 300 is reduced. That is, the tension on the thin film encapsulation layer 200 at that location during the thermal expansion and contraction of the polarizing layer 400 is significantly reduced, thereby achieving the technical objective of preventing damage to the thin film encapsulation layer 200.
[0069] In addition, in such Figure 2 and Figure 3 One embodiment shown, and Figure 4 and Figure 5In another embodiment shown, the display module for preventing black spots on the screen, in addition to the aforementioned functionalized film layers such as the thin-film encapsulation layer 200, the low surface energy material layer 300, and the polarizing layer 400, also includes the following related functional film layers: For example, a BPF (Base Polyimide Film) layer is provided below the display area 100 and the non-display area of the flexible display screen. The BPF layer 510 is the bottom substrate of the flexible display screen, and is usually a polymer film made of polyimide (PI). It has advantages such as ultra-thin and lightweight, high temperature resistance, high flexibility, and low coefficient of thermal expansion. As a carrier for structures such as the TFT (Thin Film Transistor) backplane and the OLED light-emitting layer, it mainly plays the role of maintaining the overall strength of the screen. In addition, the BPF layer 510 can also use a coating that enhances barrier properties to work together with the thin-film encapsulation layer 200 to improve the service life of the flexible display screen. For example, at the bend in the display area 100, a BPL (Barrier Protective Layer) layer 520 is also applied. This BPL layer 520 is a protective film formed by transparent optical adhesive and is an important functional layer in flexible displays used to prevent water and oxygen penetration, mechanical damage, or electrical interference. Furthermore, above the polarizing layer 400, from bottom to top, an OCA (Optically Clear Adhesive) layer, a CG lnk layer 540, and a CG (Cover Glass) layer are sequentially applied. The OCA layer 530 is a transparent film made of optical-grade adhesive. Due to its high light transmittance and excellent flexibility, it is very suitable for flexible displays. In the technical solution of this application, the outer edge of the OCA layer 530 is longer than the outer edge of the polarizing layer 400, meaning that the OCA layer 530 completely covers the polarizing layer 400. The CG layer 550 is the outermost transparent protective layer of the flexible display screen, typically made of special materials, such as, but not limited to, ultra-thin glass (UTG) or transparent polyimide (CPI). This CG layer 550 is in direct contact with the external environment and must possess flexibility, high light transmittance, and durability. Its main function is to prevent physical damage such as scratches and impacts while maintaining the display effect. The CGlnk layer 540, sandwiched between the OCA layer 530 and the CG layer 550, is a functional ink layer coated on the protective cover of the flexible display screen. Its main functions are to achieve optical shielding, circuit insulation, touch functionality, or decorative design. In the technical solution of this application, the outer edges of both the CG layer 550 and the CGlnk layer 540 must be longer than the outer edges of the bending points of the display area 100 and the BPL layer 520 to better achieve the bending and folding of the flexible display screen.
[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A display module for preventing black spots on the screen, characterized in that, The display module for preventing black spots on the screen includes: A flexible display screen has a light-emitting surface and defines a display area and a non-display area surrounding the display area. A thin-film encapsulation layer is located on the light-emitting surface. The thin-film encapsulation layer includes a display encapsulation part and a peripheral encapsulation part. The peripheral encapsulation part is disposed around the display encapsulation part and connected to the display encapsulation part. The display encapsulation part is located at a corresponding position in the display area, and the peripheral encapsulation part is located at a corresponding position in the non-display area. A polarizing layer is disposed on the side of the thin film encapsulation layer away from the light-emitting surface. The polarizing layer covers the display encapsulation portion and extends to the side of the peripheral encapsulation portion away from the light-emitting surface. A low surface energy material layer, a portion of which is located between the thin film encapsulation layer and the polarizing layer; the low surface energy material layer has a low surface energy bonding surface facing the polarizing layer, and the low surface energy bonding surface is bonded to the surface of the polarizing layer facing the low surface energy material layer with low surface energy. Wherein, the edge of the orthogonal projection of the polarizing layer on the light-emitting surface is located within the orthogonal projection of the low surface energy material layer on the light-emitting surface.
2. The display module for preventing black spots on the screen as described in claim 1, characterized in that, The low surface energy material layer is patterned and coated on a portion of the outer packaging portion.
3. The display module for preventing black spots on the screen as described in claim 1, characterized in that, The outer edge of the peripheral encapsulation portion protrudes beyond the outer edge of the polarizing layer. One end of the low surface energy material layer extends to be flush with the outer edge of the peripheral encapsulation portion, and the other end of the low surface energy material layer extends to the junction of the display encapsulation portion and the peripheral encapsulation portion.
4. The display module for preventing black spots on the screen as described in claim 1, characterized in that, The low surface energy material layer is made of a fluorine-containing low surface energy material.
5. The display module for preventing black spots on the screen as described in claim 1, characterized in that, The low surface energy material layer is a high surface roughness layer, which is formed by coating a portion of the peripheral encapsulation portion with a high surface roughness material.
6. The display module for preventing black spots on the screen as described in claim 5, characterized in that, The low surface energy bonding surface of the high surface roughness layer has a peak facing the polarizing layer and a trough opposite to the peak. The roughness of the high surface roughness material is represented by the difference between the peak and the trough, and the difference between the peak and the trough is greater than or equal to the thickness of the polarizing layer.
7. A method for manufacturing a display module with anti-black spot effect, characterized in that, The manufacturing method is used to manufacture a display module with anti-screen black spots as described in any one of claims 1 to 6, and the manufacturing method includes the following steps: The light-emitting surface of the flexible display screen to be packaged is subjected to thin-film encapsulation treatment to form a thin-film encapsulation layer in the display area and the non-display area; A low surface energy material layer is formed by patterning and coating a low surface energy material onto the peripheral encapsulation portion of the thin film encapsulation layer. The polarizing layer is attached above the thin film encapsulation layer and the low surface energy material layer.
8. The manufacturing method as described in claim 7, characterized in that, The step of patterning and coating a low surface energy material onto the peripheral encapsulation portion of the thin film encapsulation layer to form a low surface energy material layer includes the following sub-steps: A pattern of the pre-defined low surface energy material layer is formed on a printing screen; The printing screen is placed above the film encapsulation layer, and the pattern of the low surface energy material layer corresponds one-to-one with the position of the coating area on the film encapsulation layer. The patterned printing paste made of low surface energy material is used to print and coat the coating area. The low surface energy material layer is formed by drying and curing the pattern of the printed coating.
9. The manufacturing method as described in claim 7, characterized in that, The step of attaching the polarizing layer over the thin-film encapsulation layer and the low surface energy material layer includes the following sub-steps: The flexible polarizer is pretreated, and a flexible transparent optical adhesive is coated on the lower surface of the flexible polarizer facing the thin film encapsulation layer. The pre-treated flexible polarizer is vacuum-bonded onto the thin film encapsulation layer and the low surface energy material layer using a fully automatic laminating machine to form the polarizing layer; the outer edges of the thin film encapsulation layer and the low surface energy material layer both protrude beyond the outer edge of the polarizing layer; The polarizing layer is then subjected to subsequent curing and defoaming treatment.
10. A flexible display device, characterized in that, The display module includes the anti-screen black spot as described in any one of claims 1 to 6.