Folding display screen, preparation method thereof and display equipment

Abstract

The invention discloses a folding display screen and display equipment, and belongs to the technical field of electronic equipment. The folding display screen comprises a first functional layer and a second functional layer which are arranged in a stacked mode, the first functional layer and the second functional layer are directly attached, a gap part is formed by the periphery of the first functional layer and the periphery of the second functional layer which are attached, and a third functional layer is arranged on the gap part in a folding area of the folding display screen. The preparation method comprises the following steps: preparing the third functional layer at the glass edge position of the folding area of the second functional layer in a 3D direct-writing printing, piezoelectric, EHD or ink-jet manner, and laminating the first functional layer on the second functional layer. According to the folding display screen, the bending service life is obviously prolonged, the thickness of the screen is reduced, the usage amount of liquid optical materials is synchronously and remarkably reduced, the anti-static capacity and the waterproof grade of the folding display screen can be improved by additionally arranging other functional material layers, the application prospect is wide, and the practical application value is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic equipment, and in particular relates to a foldable display screen and a display device. Background Art

[0002] In recent years, miniaturization has become a new design trend for electronic products such as mobile phones and tablets. One of the most effective ways to achieve this is by designing a foldable screen. This approach not only meets the requirements for miniaturization but also reduces the inconvenience of daily use associated with a compact body. However, one of the most pressing challenges in foldable designs is how to improve the flex life of the device.

[0003] Existing technologies typically coat the middle layer of a foldable screen with a flexible liquid optical material to reduce slippage and displacement within the screen during folding, thereby enhancing the screen's bending strength, extending its lifespan, and reducing the risk of bright lines during folding. However, this technology involves complex processes, is costly for full-surface coating, and increases the thickness of the screen.

[0004] For example, patent CN118725749A discloses a folding screen adhesive, a display screen and an electronic device, wherein the folding screen adhesive comprises an acrylate optical adhesive, the acrylate optical adhesive contains a metal salt, and the acrylate optical adhesive uses a polyol acrylate as a cross-linking agent; the adhesive is used to form an optical adhesive film between two stacked functional layers in the folding screen to bond the two stacked functional layers, and the optical adhesive film is located in the folding area and the non-folding area of the folding screen; another example is patent CN117092847A discloses a liquid optical material, comprising A display panel and a bonding method, the bonding method comprising: (1) printing a liquid optical material on the surface of a touch display module by 3D printing, and forming an enclosed frame retaining wall after curing; the viscosity of the liquid optical material is ≥10000cp, and the thixotropic index is ≥2.0; (2) applying a liquid optical transparent resin to the space enclosed by the frame retaining wall, leveling and curing, to form a fully bonded optical adhesive layer including the frame retaining wall and a liquid optical adhesive layer filled in the frame retaining wall; (3) bonding a cover plate to the touch display module having the fully bonded optical adhesive layer to obtain a display panel.

[0005] As can be seen, existing technologies all use a method of fully laminating a cover plate with liquid optical adhesive to produce foldable displays. This method results in a reduction in the number of bends, a thicker screen, and a high level of material loss. Therefore, a technical solution to these problems is urgently needed. Summary of the Invention

[0006] The main purpose of the present invention is to provide a foldable display screen and a display device to solve the problems of the prior art foldable display screens such as short bending life, large screen thickness and large amount of wasted materials.

[0007] The present invention provides a folding display screen, comprising a first functional layer and a second functional layer stacked in layers. The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the folding display screen.

[0008] Furthermore, the second functional layer includes glass and a substrate, wherein the glass partially covers the substrate, and a gap is left at the edge of the glass.

[0009] Furthermore, the third functional layer is arranged at the glass edge of the folding area of the folding display screen.

[0010] Furthermore, a retaining wall is provided on the outer ring of the third functional layer.

[0011] Furthermore, the height of the retaining wall is equal to the height of the glass, and the upper surface of the third functional layer is flush with the upper surface of the glass.

[0012] Furthermore, the third functional layer includes liquid optical adhesive.

[0013] Furthermore, the third functional layer includes liquid optical glue and functional materials, and the functional materials are hydrophobic materials and / or antistatic materials.

[0014] Furthermore, the third functional layer includes a liquid optical adhesive layer and a fourth functional layer, and the fourth functional layer includes a hydrophobic and / or antistatic material.

[0015] Furthermore, the liquid optical adhesive layer and the fourth functional layer are stacked on top of each other on the substrate to form a stacked structure of at least three layers, and the fourth functional layer is an intermediate layer.

[0016] Furthermore, the liquid optical adhesive layer and the fourth functional layer are stacked in parallel horizontally or vertically on the substrate to form a stacked structure of at least three layers, and the fourth functional layer is an intermediate layer.

[0017] In a second aspect, the present invention provides a method for preparing the foldable display screen, comprising:

[0018] A third functional layer is prepared at the glass edge of the folding area of the second functional layer by using 3D direct writing printing, piezoelectric, EHD or inkjet, and the first functional layer is laminated on top of the second functional layer.

[0019] In a third aspect, the present invention also provides a display device comprising the folding display screen described above, which may include a smartphone, a personal computer, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, etc.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The folding display screen has an improved flexing lifespan. The first and second functional layers of the folding display screen of the present invention are directly bonded, and the third functional layer is arranged at the edge of the glass in the folding area. This avoids a reduction in flexing lifespan due to excessive bending stress when the liquid optical adhesive under the cover plate is fully bonded. The average number of flexing times can reach more than 170,000.

[0022] (2) The screen thickness is reduced and the amount of liquid optical material used is significantly reduced simultaneously; the third functional layer containing liquid optical glue described in the present invention is only provided at the glass edge of the folding area of the folding display screen, and does not need to be coated between the bonding surfaces of the first functional layer and the second functional layer, which can effectively reduce the overall thickness of the folding display screen, and the glue thickness can be controlled within 35±4μm, and the climbing width is ≤5μm. At the same time, the amount of liquid optical material used can be reduced, and the production cost can be reduced. It is applicable to all existing display devices containing folding displays;

[0023] (3) The antistatic ability and waterproof level of the foldable display screen can be improved; the present invention effectively improves the antistatic and waterproof capabilities of the foldable display screen by adding a fourth functional layer made of a hydrophobic or antistatic material on the third functional layer or directly mixing liquid optical materials and functional materials to prepare the third functional layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a side structural cross-sectional view of a foldable display screen in the prior art;

[0025] Figure 2 This is a side structural cross-sectional view of the foldable display screen of the present invention;

[0026] Figure 3 Schematic diagram of the folding display screen structure with two printing modes of the present invention;

[0027] Figure 4 Schematic diagram of the third functional layer structure with different printing morphologies;

[0028] Figure 5 Schematic diagram of the third functional layer structure with different printed morphologies including retaining walls;

[0029] Figure 6 Schematic diagram of the third functional layer structure with different stacking methods;

[0030] Figure 7Print a structural diagram for the retaining wall;

[0031] Figure 8 Print a structural diagram for the third functional layer;

[0032] Figure 9 Schematic diagram of the structure of liquid optical adhesive layer and functional adhesive layer stacked up and down;

[0033] Figure 10 Schematic diagram of the printing device structure;

[0034] Figure 11 Print a physical image for the third functional layer;

[0035] Figure 12 It is the sensor height scan diagram;

[0036] Explanation of the figure marks: 1-first functional layer, 2-second functional layer, 3-third functional layer, 4-fourth functional layer, 5-retaining wall, 6-glass, 7-substrate, 8-folding area, 9-gantry, 10-visual camera, 11-retaining wall print head, 12-UV curing device, 13-suction cup, 14-base, 15-first filling print head, 16-second filling print head, 17-third filling print head. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0038] As mentioned in the background technology section of the present invention, miniaturized foldable designs are gradually becoming a new design direction for display electronic products such as mobile phones and tablets. The existing technology usually adopts a layer of flexible liquid optical material coated on the middle layer area of the bending screen to reduce the slippage and displacement inside the screen when bending, thereby enhancing the bending strength of the screen, thereby increasing the service life of the screen and reducing the risk of bright lines on the screen during the folding process. Its cross-sectional structure is as follows: Figure 1 However, the folding display screen prepared in this way has a high cost for coating the entire surface, and inevitably increases the thickness of the screen, resulting in greater stress during bending, and generally has problems such as reduced bending times, thicker screen, and more wasted material. To solve the above problems, the present invention provides a third functional layer on both sides of the second functional layer glass in the folding area, which can effectively improve the bending life of the screen while reducing the thickness of the screen. Figure 2 and Figure 3As shown; in addition, other functional materials such as hydrophobic glue can be added to improve the waterproof effect of the bending area, or anti-static glue can be used to prevent static electricity generated by friction inside the screen during the bending process.

[0039] The present invention provides a folding display screen, comprising a first functional layer 1 and a second functional layer 2 stacked together. The first functional layer 1 and the second functional layer 2 are directly bonded together (without the need to fill liquid optical material between them). A gap is formed around the bonded first functional layer 1 and the second functional layer 2. A third functional layer 3 is provided in the gap in the folding area 8 of the folding display screen.

[0040] In some specific embodiments, the first functional layer 1 is selected from a flexible substrate, specifically polyethylene terephthalate (PET); the second functional layer 2 includes glass 6 and a substrate 7, wherein the glass 6 partially covers the substrate 7, leaving a gap around the edge of the glass 6. Specifically, the glass 6 leaves a certain gap at least on both sides of the substrate 7, or leaves a certain gap around the substrate 7.

[0041] In some specific embodiments, the third functional layer 3 is arranged on both sides of the glass 6 of the folding area 8 of the folding display screen, and its morphology can be dot-shaped, elliptical or other special-shaped structures, such as Figure 4 As shown. Preferably, the outer ring of the third functional layer 3 can be provided with a retaining wall 5 to more accurately define the morphology of the third functional layer 3 and ensure better filling consistency, so that the third functional layer 3 and the first functional layer 1 have better fit. Figure 5 As shown, the shape of the third functional layer 3 can be determined by the retaining wall 5 and can be adjusted in various ways according to product requirements. Specifically, it can be a square, triangle, elliptical or other special-shaped structures.

[0042] In some specific embodiments, the height of the retaining wall 5 is equal to the height of the glass 6 , and the upper surface of the third functional layer 3 is flush with the upper surface of the glass 6 , which is conducive to a closer fit between the first functional layer 1 and the second functional layer 2 .

[0043] In some specific embodiments, the third functional layer 3 includes liquid optical adhesive.

[0044] In some specific embodiments, the third functional layer 3 includes liquid optical glue and functional materials, and the functional materials are hydrophobic materials and / or antistatic materials and / or other materials with special functions; wherein the hydrophobic material is used to improve the waterproof effect of the folding area, and the antistatic material is used to prevent static electricity generated by friction inside the screen during the bending process.

[0045] In some specific embodiments, the third functional layer 3 includes a liquid optical adhesive layer and a fourth functional layer 4 , and the fourth functional layer 4 includes a hydrophobic and / or antistatic material and / or other materials with special functions.

[0046] In some specific embodiments, the liquid optical adhesive layer and the fourth functional layer 4 are stacked on the substrate 7 to form a stacked structure of at least three layers, and the fourth functional layer 4 is an intermediate layer. Figure 6 shown.

[0047] In some specific embodiments, the liquid optical adhesive layer and the fourth functional layer 4 are stacked horizontally or vertically in parallel on the substrate 7 to form a stacked structure of at least three layers, and the fourth functional layer 4 is an intermediate layer, such as Figure 6 shown.

[0048] The method for preparing the foldable display screen includes:

[0049] The third functional layer 3 is prepared at the edge of the glass 6 in the folding area 8 of the second functional layer 2 using 3D direct writing printing, piezoelectric, EHD, or inkjet printing. The first functional layer 1 is then laminated on top of the second functional layer 2. During the printing process, data is first collected about the printing position. Then, the sensor scans the height data and correlates it with the printing pin-to-pin distance, ensuring consistent printing distance at different locations and improving the printing accuracy of the retaining wall 5.

[0050] In some specific embodiments, the above preparation method further includes printing a retaining wall 5 at the edge of the glass 6 in the folding area 8 of the second functional layer 2 to determine the morphology of the third functional layer 3, and then filling the area surrounded by the glass 6 and the retaining wall 5 with liquid optical glue, such as Figure 7 and Figure 8 shown.

[0051] Specifically, when the liquid optical adhesive layer and the fourth functional layer 4 are stacked on top of each other on the substrate 7, the preparation method includes:

[0052] In the area enclosed by the retaining wall 5 and the glass 6, the liquid optical adhesive layer, the fourth functional layer 4 and the liquid optical adhesive layer are printed in sequence from bottom to top to form a sandwich structure stacked up and down, such as Figure 9 As shown;

[0053] When the liquid optical adhesive layer and the fourth functional layer 4 are stacked in parallel horizontally or vertically on the substrate 7, the preparation method includes:

[0054] In the area enclosed by the retaining wall 5 and the glass 6, the liquid optical adhesive layer, the fourth functional layer 4 and the liquid optical adhesive layer are printed vertically from left to right to form a vertically stacked three-layer structure; or in the area enclosed by the retaining wall 5 and the glass 6, the liquid optical adhesive layer, the fourth functional layer 4 and the liquid optical adhesive layer are printed horizontally from front to back to form a horizontally stacked three-layer structure.

[0055] In addition, according to the specific needs of the product, pre-treatment (such as solvent wiping, Plasma, etc.), glue curing (UV, IR, laser) and other steps can be carried out before, during and after printing.

[0056] Example 1

[0057] The foldable display screen of this embodiment includes a first functional layer and a second functional layer stacked in layers. The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the foldable display screen, and the third functional layer is provided at the glass edge of the folding area of the foldable display screen. Figure 10 As shown, a visual camera 10, a retaining wall print head 11, a UV curing device 12, a first filling print head 15, a second filling print head 16 and a third filling print head 17 are fixed on the gantry 9. The first filling print head 15, the second filling print head 16 and the third filling print head 17 are used for printing liquid optical materials, hydrophobic materials and antistatic materials respectively. A suction cup 13 is fixed on the base 14. The suction cup 13 absorbs the product to be printed and can be moved arbitrarily on the base 14.

[0058] 1. Loading and machine preparation:

[0059] After the liquid optical material is poured into the material tube, it is installed on the piezoelectric valve (or inkjet) and connected to the pneumatic dispensing machine. The liquid optical material is optical clear resin (OCR). The printing parameters are set.

[0060] 2. Sample printing:

[0061] 1) Visual recognition and edge inspection, angle correction, and positioning of the printing starting point;

[0062] 2) Move to the printing station and use a piezoelectric valve (or inkjet) to complete the liquid optical adhesive printing;

[0063] 3) Move to the bottom of the UV curing device to cure the liquid optical adhesive material;

[0064] 4) Move to the unloading area and unload the substrate;

[0065] 5) Obtaining the printed second functional layer;

[0066] 6) Laminating the PET layer (self-adhesive) to the glass surface of the second functional layer to prepare a foldable display screen.

[0067] Example 2

[0068] The folding display screen described in this embodiment includes a first functional layer and a second functional layer that are stacked together. The first functional layer and the second functional layer are directly bonded together, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the folding display screen. The third functional layer is arranged at the glass edge of the folding area of the folding display screen, and a retaining wall is provided on the outer circle of the third functional layer.

[0069] The printing device is the same as that in Example 1. The specific operation steps are as follows:

[0070] 1. Loading and machine preparation:

[0071] 1) Pour retaining wall material into the material tube and install it on the pneumatic dispensing machine;

[0072] 2) Filling the tube with a filling material, which is an optically clear resin (OCR), and then mounting it on a piezoelectric valve (or inkjet) and connecting it to a pneumatic dispenser.

[0073] 3) Set the enclosure printing parameters;

[0074] 2. Sample printing:

[0075] 1) Visual recognition and edge inspection, angle correction, and positioning of the printing starting point;

[0076] 2) Collect the height data of the retaining wall printing position and obtain the compensation data to the printing needle surface distance parameters;

[0077] 3) The retaining wall printing device moves to the printing starting point and drops to the printing height;

[0078] 4) Complete the retaining wall printing according to the pre-designed parameters;

[0079] 5) Move to the bottom of the UV device to cure the retaining wall;

[0080] 6) Move to the printing station and use the piezoelectric valve (or inkjet) to complete the filling glue printing;

[0081] 7) Move to the bottom of the UV curing device to cure the filling glue material;

[0082] 8) Move to the unloading area and unload the substrate;

[0083] 9) Get the second functional layer after printing, and see the actual product picture for details. Figure 11 Left side picture;

[0084] 10) Laminating the PET layer to the glass surface of the second functional layer to prepare a foldable display screen.

[0085] Example 3

[0086] The foldable display screen of this embodiment includes a first functional layer and a second functional layer stacked in layers. The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the foldable display screen. The third functional layer is arranged at the glass edge of the folding area of the foldable display screen, and a retaining wall is provided on the outer circle of the third functional layer. The third functional layer includes a liquid optical adhesive layer and a fourth functional layer, and the fourth functional layer is made of an antistatic material.

[0087] The printing device is the same as that in Example 1. The specific operation steps are as follows:

[0088] 1. Loading and machine preparation:

[0089] 1) Pour retaining wall material into the material tube and install it on the pneumatic dispensing machine;

[0090] 2) After filling the material into the tube, install it on the piezoelectric valve (or inkjet) and connect it to the pneumatic dispensing machine; the filling material is optical clear resin (OCR), and the antistatic adhesive uses Hitachi Chemical's antistatic acrylic adhesive material;

[0091] 3) Set the enclosure printing parameters;

[0092] 2. Sample printing:

[0093] 1) Visual recognition and edge inspection, angle correction, and positioning of the printing starting point;

[0094] 2) Collect the height data of the retaining wall printing position and obtain the compensation data to the printing needle surface distance parameters;

[0095] 3) The retaining wall printing device moves to the printing starting point and drops to the printing height;

[0096] 4) Complete the retaining wall printing according to the pre-designed parameters;

[0097] 5) Move to the bottom of the UV device to cure the retaining wall;

[0098] 6) Move to the printing station and use a piezoelectric valve (or inkjet) to complete the filling glue printing. The filling glue printing includes printing liquid optical glue and antistatic glue separately. Each filling is completed and UV cured once. Among them, the liquid optical glue layer and the antistatic glue layer are stacked horizontally on the substrate. The liquid optical glue layer, antistatic glue layer and liquid optical glue layer are printed in sequence from front to back in the area of the retaining wall and glass enclosure, forming a horizontally stacked three-layer structure;

[0099] 7) Move to the bottom of the UV curing device to cure the filling glue material;

[0100] 8) Move to the unloading area and unload the substrate;

[0101] 9) Get the second functional layer after printing, and see the actual product picture for details. Figure 11 Right side picture;

[0102] 10) Laminating the PET layer to the glass surface of the second functional layer to prepare a foldable display screen.

[0103] Figure 12 This is a sensor height scan diagram. It can be seen from the diagram that this embodiment can achieve a flatness of 35μm±4μm. Under the premise of the dam blocking, the climbing distance of the filling glue is very short, or even almost non-existent.

[0104] Example 4

[0105] The foldable display screen of this embodiment includes a first functional layer and a second functional layer stacked in layers. The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the foldable display screen. The third functional layer is arranged at the glass edge of the folding area of the foldable display screen, and a retaining wall is provided on the outer circle of the third functional layer. The third functional layer includes a liquid optical adhesive layer and a fourth functional layer, and the fourth functional layer is made of an antistatic material.

[0106] The printing device is the same as that in Example 1. The specific operation steps are as follows:

[0107] 1. Loading and machine preparation:

[0108] 1) Pour retaining wall material into the material tube and install it on the pneumatic dispensing machine;

[0109] 2) After filling the material into the tube, install it on the piezoelectric valve (or inkjet) and connect it to the pneumatic dispensing machine; the filling material is optical clear resin (OCR), and the antistatic adhesive uses Hitachi Chemical's antistatic acrylic adhesive material;

[0110] 3) Set the enclosure printing parameters;

[0111] 2. Sample printing:

[0112] 1) Visual recognition and edge inspection, angle correction, and positioning of the printing starting point;

[0113] 2) Collect the height data of the retaining wall printing position and obtain the compensation data to the printing needle surface distance parameters;

[0114] 3) The retaining wall printing device moves to the printing starting point and drops to the printing height;

[0115] 4) Complete the retaining wall printing according to the pre-designed parameters;

[0116] 5) Move to the bottom of the UV device to cure the retaining wall;

[0117] 6) Move to the printing station and use a piezoelectric valve (or inkjet) to complete the filling glue printing. The filling glue printing includes printing the liquid optical adhesive layer and the antistatic adhesive separately. Each filling is completed and UV cured once. The liquid optical adhesive layer and the antistatic adhesive layer are stacked vertically on the substrate. The liquid optical adhesive layer, the antistatic adhesive layer, and the liquid optical adhesive layer are printed vertically from left to right in the area of the retaining wall and glass enclosure, forming a vertically stacked three-layer structure.

[0118] 7) Move to the bottom of the UV curing device to cure the filling glue material;

[0119] 8) Move to the unloading area and unload the substrate;

[0120] 9) Obtaining the printed second functional layer;

[0121] 10) Laminating the PET layer to the glass surface of the second functional layer to prepare a foldable display screen.

[0122] Example 5

[0123] The foldable display screen of this embodiment includes a first functional layer and a second functional layer stacked in layers. The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the foldable display screen. The third functional layer is arranged at the glass edge of the folding area of the foldable display screen, and a retaining wall is provided on the outer circle of the third functional layer. The third functional layer includes a liquid optical adhesive layer and a fourth functional layer, and the fourth functional layer is made of an antistatic material.

[0124] The printing device is the same as that in Example 1. The specific operation steps are as follows:

[0125] 1. Loading and machine preparation:

[0126] 1) Pour retaining wall material into the material tube and install it on the pneumatic dispensing machine;

[0127] 2) After filling the material into the tube, install it on the piezoelectric valve (or inkjet) and connect it to the pneumatic dispensing machine; the filling material is optical clear resin (OCR), and the antistatic adhesive uses Hitachi Chemical's antistatic acrylic adhesive material;

[0128] 3) Set the enclosure printing parameters;

[0129] 2. Sample printing:

[0130] 1) Visual recognition and edge inspection, angle correction, and positioning of the printing starting point;

[0131] 2) Collect the height data of the retaining wall printing position and obtain the compensation data to the printing needle surface distance parameters;

[0132] 3) The retaining wall printing device moves to the printing starting point and drops to the printing height;

[0133] 4) Complete the retaining wall printing according to the pre-designed parameters;

[0134] 5) Move to the bottom of the UV device to cure the retaining wall;

[0135] 6) Move to the printing station and use a piezoelectric valve (or inkjet) to complete the filling glue printing. The filling glue printing includes printing the liquid optical glue layer and the antistatic glue separately. One filling is completed and UV curing is performed once. Among them, the liquid optical glue layer and the antistatic glue layer are stacked up and down on the substrate. In the area of the retaining wall and glass enclosure, the liquid optical glue layer, the antistatic glue layer and the liquid optical glue layer are printed from bottom to top in sequence to form a sandwich structure stacked up and down, such as Figure 9 As shown;

[0136] 7) Move to the bottom of the UV curing device to cure the filling glue material;

[0137] 8) Move to the unloading area and unload the substrate;

[0138] 9) Obtaining the printed second functional layer;

[0139] 10) Laminating the PET layer to the glass surface of the second functional layer to prepare a foldable display screen.

[0140] Example 6

[0141] On the basis of Example 3, the antistatic glue is modified into hydrophobic glue to improve the waterproof function of the product. The hydrophobic glue uses acrylic hydrophobic glue.

[0142] Example 7

[0143] On the basis of Example 4, the antistatic glue is modified into hydrophobic glue to improve the waterproof function of the product, and the hydrophobic glue uses acrylic hydrophobic glue.

[0144] Example 8

[0145] On the basis of Example 5, the antistatic glue is modified into hydrophobic glue to improve the waterproof function of the product, and the hydrophobic glue uses acrylic hydrophobic glue.

[0146] Example 9

[0147] This embodiment provides a display device including a foldable display screen. The structure of the foldable display screen is similar to any of the above embodiments and will not be further described here. The display device may include a smartphone, a personal computer, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, and the like.

[0148] Comparative Example

[0149] The foldable display screen of this comparative example includes a first functional layer and a second functional layer, and a liquid optical adhesive layer OCR is provided between the first functional layer and the second functional layer, that is, the two layers are not directly bonded, and the structure is as follows: Figure 1 shown.

[0150] The foldable display screens prepared in the above embodiments and comparative examples were subjected to performance tests, including the number of bends, antistatic level, waterproof level, glue thickness, and climbing width. The test data are shown in Table 1.

[0151] The test conditions are as follows:

[0152] Anti-static level test: Use a four-point probe tester to test according to IEC 61340-2-3 or ASTM D257 standards;

[0153] Bending times test: The folding life test machine is used to calculate the number of bends. If the screen has cracks, delamination or optical defects, the test will be stopped.

[0154] Waterproof level test: Assemble the screen and immerse the device in water at a depth of 1 meter for 30 minutes or longer. Observe whether there is any water seepage into the screen. After removing the device, check whether the screen can work normally and whether there is any water inside.

[0155] Table 1

[0156] plan Example 1 Example 2 Example 3 Example 6 Comparative Example Number of bends 170,000 times 170,000 times 180,000 times 180,000 times 150,000 times Anti-static grade <![CDATA[10 8 Ohm / sq]]> <![CDATA[10 9 Ohm / sq]]> <![CDATA[10 10 Ohm / sq]]> <![CDATA[10 9 Ohm / sq]]> <![CDATA[10 12 Ohm / sq]]> Waterproof grade IPX7 IPX8 IPX8 IPX9 IPX7 Glue thickness 32μm 32μm 30μm 31μm 120μm Climbing width 8μm 2μm 2μm 2μm 30μm

[0157] As can be seen from Table 1, compared to the comparative example, the present invention achieves an increase in the bending life of the folding display screen, a reduction in screen thickness, and a significant reduction in the amount of liquid optical material used, as well as a significant improvement in anti-static ability and waterproof level. First, the first and second functional layers of the folding display screen of the present invention are directly bonded, and the third functional layer is provided at the glass edge of the folding area. This avoids the reduction in bending life caused by excessive bending stress when the liquid optical adhesive under the cover plate is fully bonded. Second, the third functional layer containing liquid optical adhesive of the present invention is only provided at the glass edge of the folding area of the folding display screen, without the need to be coated between the bonding surfaces of the first and second functional layers. This can effectively reduce the overall thickness of the folding display screen, with the adhesive thickness being controllable within 35±4μm and the climbing width being ≤5μm. At the same time, it can also reduce the amount of liquid optical material used, reduce production costs, and is suitable for all existing display devices containing folding displays. Finally, the present invention can effectively improve the anti-static and waterproof capabilities of the folding display screen by adding a fourth functional layer made of hydrophobic or anti-static material on the third functional layer or directly mixing the liquid optical material and functional material.

[0158] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0159] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0160] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall all fall within the scope defined by the present invention.

Claims

1. A foldable display screen comprising a first functional layer and a second functional layer stacked together, characterized in that: The first functional layer and the second functional layer are directly bonded to each other, and a gap is formed around the bonded first and second functional layers. A third functional layer is provided in the gap in the folding area of the folding display screen.

2. The foldable display screen according to claim 1, wherein: The second functional layer includes glass and a substrate, wherein the glass partially covers the substrate, and a gap is left at the edge of the glass.

3. The foldable display screen according to claim 1, wherein: The third functional layer is arranged at the glass edge of the folding area of the folding display screen.

4. The foldable display screen according to claim 1, wherein: The outer circle of the third functional layer is provided with a retaining wall.

5. The foldable display screen according to claim 1, wherein: The height of the retaining wall is equal to the height of the glass, and the upper surface of the third functional layer is flush with the upper surface of the glass.

6. The foldable display screen according to claim 1, wherein: The third functional layer includes liquid optical adhesive.

7. The foldable display screen according to claim 1, wherein: The third functional layer includes liquid optical glue and functional materials, and the functional materials are hydrophobic materials and / or antistatic materials.

8. The foldable display screen according to claim 1, wherein: The third functional layer includes a liquid optical adhesive layer and a fourth functional layer, and the fourth functional layer includes a hydrophobic and / or antistatic material.

9. The foldable display screen according to claim 1, wherein: The liquid optical adhesive layer and the fourth functional layer are stacked on top of each other on the substrate to form a stacked structure of at least three layers, and the fourth functional layer is an intermediate layer.

10. The foldable display screen according to claim 1, wherein: The liquid optical adhesive layer and the fourth functional layer are stacked in parallel horizontally or vertically on the substrate to form a stacked structure of at least three layers, and the fourth functional layer is an intermediate layer.

11. A method for preparing the foldable display screen according to any one of claims 1 to 10, characterized in that: include: A third functional layer is prepared at the glass edge of the folding area of the second functional layer by using 3D direct writing printing, piezoelectric, EHD or inkjet, and the first functional layer is laminated on top of the second functional layer.

12. A display device, characterized in that: Including the foldable display screen described in any one of claims 1-10.

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