Flexible covering window and preparation method and application thereof

Abstract

The invention provides a flexible covering window and a preparation method and application thereof.The preparation method comprises the steps that a glass substrate is thinned for the first time, the glass substrate is thinned to the required thickness, then the thinned glass substrate is directly thinned for the second time through acid liquor, a display area and a folding area are formed on the glass substrate, and the display area and the folding area are formed on the glass substrate; and finally, thinning the folding area on the glass substrate for the third time, and forming a micro-texture structure in the folding area, so as to obtain the flexible covering window. According to the manufacturing method, the yellow light technology is not adopted for second-time thinning, pure etching thinning is conducted only by immersing the flexible cover window into the acid liquor, the manufacturing method has the advantages of being low in cost and high in yield, it can be guaranteed that the display area of the manufactured flexible cover window has high strength, and meanwhile the folding area has good bending performance.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to a flexible cover window and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of electrical and electronic technology, consumers have higher and higher requirements for various types of display products. As a display tool that displays certain electronic files on the screen through a specific transmission device and then reflects them to the human eye, flexible displays that can be folded and unfolded have been favored by consumers. At the same time, with the continuous development of display production technology and the continuous improvement of related materials, many types of displays have appeared, including flexible displays. For flexible displays, research is being conducted from basic folding to bending, winding and stretching. Not only the display panel is flexible, but the cover window used to protect the display panel also needs to be flexible.

[0003] CN113362708A discloses a flexible cover window and a manufacturing method thereof, wherein the flexible cover window is a glass-based flexible cover window, and the flexible cover window comprises: a planar portion formed corresponding to a planar area of ​​a flexible display; and a folding portion formed by connecting the planar portion and formed corresponding to a folding area of ​​the flexible display, wherein the flexible cover window is characterized in that the folding portion comprises a pattern portion for impact compensation, and the pattern portion for impact compensation is composed of a cylindrical pattern.

[0004] However, the preparation method of the above-mentioned flexible cover window includes two etchings. The first etching is to form a depression in the display area and the folding area, and the second etching is to form a columnar stripe texture. However, the processes used in the two etchings are both yellow light etching processes, that is, an etching-resistant material is used to protect a part of the area and then the non-protected area is etched and thinned. This will result in a high preparation cost of the flexible cover window and a low yield of the obtained product. At the same time, since the pattern formed by the yellow light etching process is too large, the subsequent filling process cannot effectively cover the texture of the display area. The final finished product will have a point-like texture visible to the naked eye, resulting in an unqualified product appearance.

[0005] Therefore, there is an urgent need to develop a method for preparing a flexible cover window to solve at least one of the above technical problems. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a flexible cover window and a preparation method and application thereof. The preparation method can form a folding area on a glass substrate by a pure etching and thinning process without using a yellow light etching process, and has the advantages of low cost and high yield. The display area of ​​the prepared flexible cover window has higher strength, and the folding area has better bending performance.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a flexible cover window, the method comprising the following steps:

[0009] (1) performing first thinning, cutting, and single-side protection on the glass substrate in sequence to obtain a glass substrate with a protective layer;

[0010] (2) laminating one side surface of the protective layer of the glass substrate with the protective layer obtained in step (1) to a backing plate, and immersing the glass substrate in an acid solution for a second thinning to obtain a glass substrate including a display area and a folding area;

[0011] (3) The folding area of ​​the glass substrate including the display area and the folding area obtained in step (2) is thinned for a third time to form a micro texture in the folding area, and after removing the protective layer, the folding area is strengthened and coated to obtain the flexible cover window.

[0012] Preferably, the method for the first thinning in step (1) is specifically: using hydrofluoric acid to perform double-sided spray etching on the initial glass substrate to complete the first thinning.

[0013] Preferably, the thickness of the glass substrate after the first thinning in step (1) is 100-300 μm, for example, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 260 μm or 280 μm.

[0014] Preferably, the cutting in step (1) is laser cutting and / or glass knife cutting.

[0015] Preferably, the single-sided protection in step (1) comprises single-sided UV acid-proof film, single-sided silk-screen ink or single-sided spray photoresist.

[0016] Preferably, the lining board in step (2) is an acid-resistant lining board.

[0017] Preferably, the specific method for the second thinning in step (2) is: immersing one end of the glass substrate bonded with the liner into the acid solution along a direction parallel to the bonding line, taking it out, and then immersing the other end of the glass substrate bonded with the liner into the acid solution again along a direction parallel to the bonding line, and taking it out again to obtain a glass substrate including a display area and a folding area, thereby completing the second thinning.

[0018] Preferably, the glass substrate bonded with the backing plate is etched by the acid solution at a rate of 1 to 5 μm / min, for example, 1.5 μm / min, 2 μm / min, 2.5 μm / min, 3 μm / min, 3.5 μm / min, 4 μm / min or 4.5 μm / min.

[0019] Preferably, the acid solution comprises hydrofluoric acid.

[0020] Preferably, the acid solution further comprises any one of nitric acid, sulfuric acid or hydrochloric acid, or a combination of at least two of them.

[0021] Preferably, the depth of the two immersions in the acid solution exceeds half of the length of the glass substrate in the direction parallel to the bonding line.

[0022] The third thinning in step (3) is yellow light etching thinning.

[0023] Preferably, the strengthening in step (3) is potassium nitrate strengthening.

[0024] As a preferred technical solution, the preparation method comprises the following steps:

[0025] (1) using hydrofluoric acid to perform double-sided spray etching on the glass substrate to reduce the thickness of the glass substrate to a desired thickness of 100 to 300 μm, completing the first thinning, and then performing laser cutting and / or glass knife cutting on the glass substrate after the first thinning, and performing single-sided protection on one side of the surface of the cut glass substrate to obtain a glass substrate with a protective layer;

[0026] (2) bonding one side of the glass substrate with the protective layer obtained in step (1) to an acid-resistant backing plate, and then immersing one end of the glass substrate with the acid-resistant backing plate in an acid solution along a direction parallel to the bonding line, the immersion depth exceeding half of the length of the glass substrate parallel to the bonding line, taking it out, and then immersing the other end of the glass substrate with the acid-resistant backing plate in the acid solution again along a direction parallel to the bonding line, the immersion depth also exceeding half of the length of the glass substrate parallel to the bonding line, and taking it out again, completing the second thinning, and obtaining a glass substrate including a display area and a folding area;

[0027] (3) The folding area of ​​the glass substrate including the display area and the folding area obtained in step (2) is subjected to a third yellow light etching thinning to form a micro texture in the folding area of ​​the glass substrate, the protective layer is removed, and potassium nitrate strengthening and coating are performed to obtain the flexible cover window.

[0028] In a second aspect, the present invention provides a flexible cover window, wherein the flexible cover window is prepared by the preparation method described in the first aspect.

[0029] Preferably, the flexible cover window comprises a glass substrate;

[0030] A display area and a folding area are provided on the glass substrate, wherein the folding area is located in the middle of the display area and is thinner than the display area;

[0031] The folding area has a micro-texture structure, and the micro-texture structure includes a plurality of raised textures. The shapes of the raised textures are regular shapes, irregular shapes, or a combination of regular shapes and irregular shapes.

[0032] Preferably, the thickness of the glass substrate of the display area is 70-200 μm, for example, 70 μm, 90 μm, 110 μm, 130 μm, 150 μm, 170 μm or 190 μm.

[0033] Preferably, the thickness of the glass substrate in the folding area is 25-50 μm, for example, 25 μm, 30 μm, 35 μm, 40 μm or 45 μm.

[0034] Preferably, the raised height of the raised texture is 5 to 50 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or 45 μm.

[0035] Preferably, the distance between two adjacent raised textures is 0.005-1 mm, for example, 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm.

[0036] It should be noted that the above-mentioned “distance between two adjacent raised textures” refers to the distance between adjacent surfaces of two adjacent raised textures.

[0037] Preferably, the regular shape is an axisymmetric regular shape.

[0038] Preferably, the axisymmetric regular shape is a bar, a sphere, a racetrack, a hexagon or a five-pointed star.

[0039] Preferably, the raised texture is strip-shaped, the width of the strip-shaped raised texture is 0.01-1 mm (for example, 0.02 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm or 0.8 mm, etc.), and the distance between two adjacent strip-shaped raised textures is 0.01-1 mm (for example, 0.02 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm or 0.8 mm, etc.).

[0040] Preferably, the raised texture is circular, the diameter of the circular raised texture is 0.01-1 mm (for example, 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm or 0.8 mm, etc.), and the distance between two adjacent circular raised textures is 0.005-1 mm (for example, 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm or 0.8 mm, etc.).

[0041] Preferably, the irregular shape includes a dart shape or an I-shape.

[0042] In a third aspect, the present invention provides an application of the flexible cover window as described in the second aspect in a flexible display.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The preparation method of the flexible cover window provided by the present invention first performs a first thinning on a glass substrate to thin the glass substrate to a desired thickness, then uses an acid solution to directly perform a second thinning on the thinned glass substrate to form a display area and a folding area on the glass substrate, and finally performs a third thinning on the folding area on the glass substrate to form a micro-texture structure in the folding area to obtain the flexible cover window; the second thinning in the preparation method does not use a yellow light process, but only performs pure etching thinning by immersing in an acid solution, so that the preparation method has the advantages of low cost and high yield, and can also ensure that the display area of ​​the prepared flexible cover window has high strength, and the folding area has better bending performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A process flow chart of a method for preparing a flexible cover window provided by the present invention;

[0046] Figure 2 A schematic diagram of the second thinning process in the method for preparing the flexible cover window provided by the present invention;

[0047] Figure 3 This is a schematic diagram of the process of immersing in acid solution during the second thinning;

[0048] Figure 4 A schematic diagram of the cross-sectional structure of the flexible cover window provided by the present invention;

[0049] Figure 5 A schematic diagram of the planar structure of a flexible cover window with a strip-shaped raised texture provided by the present invention;

[0050] Figure 6 A schematic diagram of the planar structure of a flexible cover window with a circular raised texture provided by the present invention;

[0051] Figure 7 A schematic diagram of the planar structure of a flexible cover window with a dart-shaped raised texture provided by the present invention;

[0052] Among them, 100-glass substrate, 110-display area, 120-folding area, 200-protective layer, 300-backing plate. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] Hereinafter, the flexible cover window and the preparation method thereof provided by the present invention will be described in detail with reference to the accompanying drawings;

[0055] In a specific embodiment of the present invention, the present invention provides a method for preparing a flexible cover window, and the process flow chart of the preparation method is as follows: Figure 1 As shown, the specific steps include:

[0056] (1) The glass substrate 100 is thinned for the first time, cut, and protected on one side in sequence to obtain a glass substrate 100 having a protective layer 200;

[0057] (2) laminating one side of the protective layer 200 of the glass substrate 100 having the protective layer 200 obtained in step (1) to the backing plate 300, and immersing the glass substrate 100 in an acid solution for a second thinning, thereby obtaining a glass substrate 100 including a display area 110 and a folding area 120;

[0058] (3) The folding area 120 of the glass substrate 100 including the display area 110 and the folding area 120 obtained in step (2) is thinned for the third time to form a micro texture in the folding area 120, and the protective layer 200 is removed. After strengthening and coating, the flexible cover window is obtained.

[0059] In a preferred embodiment, the first thinning method in step (1) is as follows: using hydrofluoric acid to perform double-sided spray etching on the glass substrate 100 to reduce the thickness of the glass substrate 100 to the required 100-300 μm, thereby completing the first thinning.

[0060] In a preferred embodiment, the cutting in step (1) is performed by laser cutting and / or a glass cutter, and the purpose is to cut the thinned glass substrate 100 into a smaller set size.

[0061] In a preferred embodiment, the above-mentioned single-sided protection method is specifically: a UV acid-proof film, silk-screen ink or spray photoresist is attached to one side surface of the glass substrate 100 to obtain a glass substrate 100 with a protective layer 110, which can effectively protect the single-side surface of the glass substrate.

[0062] In a preferred embodiment, the lining plate 300 in the above step (2) is an acid-resistant lining plate, which includes but is not limited to engineering PC materials and the like. More preferably, a glass substrate with a protective layer is centrally attached to the acid-resistant lining plate.

[0063] In a preferred embodiment, the schematic diagram of the second thinning process in step (2) is as follows: Figure 2 As shown, Figure 2 In FIG. 1 , the dotted line is the median line of the glass substrate 100; Figure 2 It can be seen that the second thinning specifically includes: firstly immersing one end of the glass substrate 100 attached with the liner 300 into the acid solution for the first time in a direction parallel to the bonding line and then taking it out, rotating it 180°, and then immersing the other end of the glass substrate 100 attached with the liner 300 into the acid solution for the second time in a direction parallel to the bonding line and taking it out, so as to obtain the glass substrate 100 including the display area 110 and the folding area 120, and completing the second thinning;

[0064] In the second thinning process, one end of the glass substrate 100 bonded with the liner 300 is immersed in the acid solution along the direction parallel to the bonding line. Figure 3 As shown, Figure 3 In the figure, the arrow direction is parallel to the bonding line, and the dotted line is the median line of the glass substrate; Figure 3 It can be seen that the depth of the two immersions in the acid solution must exceed half of the length of the target glass substrate parallel to the bonding line direction (that is, it needs to exceed the median line of the glass substrate). The specific depth can be 1 to 30 mm, which needs to be set according to the target product requirements.

[0065] In a preferred embodiment, during the second thinning process, the acid solution must contain hydrofluoric acid, and may also contain any one of nitric acid, sulfuric acid or hydrochloric acid, or a combination of at least two of them.

[0066] In a preferred embodiment, the time of the two immersions in the acid solution is independently 10 to 30 minutes.

[0067] From the above content, it can be found that the second thinning in step (2) of the preparation method of the flexible cover window provided by the present invention is pure etching thinning, and no yellow light process is used, and there is no need to set a protective coating in advance, thereby effectively reducing the process cost and effectively improving the yield of the product; specifically, the yield of the flexible cover window prepared by the preparation method provided by the present invention can reach 70%, and the cost can be reduced by about 50%.

[0068] In a preferred embodiment, the third thinning in step (3) is a conventional yellow light etching thinning process. Specifically, it is necessary to apply protective oil to the folding area before etching. The protective oil is directly applied to the surface of the glass substrate 100 that does not want to be etched in the folding area to protect it, and then immersion or spray etching is performed to form a micro-texture structure in the folding area 110.

[0069] In another specific embodiment provided by the present invention, the present invention provides a flexible cover window, the cross-sectional structure schematic diagram of the flexible cover window is as follows: Figure 4 As shown, it includes a glass substrate 100;

[0070] The glass substrate 100 is provided with a display area 110 and a folding area 120 , wherein the folding area 120 is located in the middle of the display area 110 and is thinner than the display area;

[0071] The folding area 120 has a micro-texture structure, and the micro-texture structure includes a plurality of raised textures. The shapes of the raised textures are regular shapes, irregular shapes, or a combination of regular shapes and irregular shapes.

[0072] In a preferred embodiment, the thickness of the glass substrate of the display area 110 is 70-200 μm, and the thickness of the glass substrate of the folding area 120 is 25-50 μm.

[0073] In a preferred embodiment, the distance between two adjacent raised textures in the folding area 120 is 0.005-1 mm, and the raised height of each raised texture is 5-50 μm.

[0074] In a preferred embodiment, the regular shape is a bar, a sphere, a racetrack, a hexagon or a five-pointed star.

[0075] In a preferred embodiment, the raised texture is strip-shaped, the width of the strip-shaped raised texture is 0.01 to 1 mm, and the distance between two adjacent strip-shaped raised textures is 0.01 to 1 mm; the strip-shaped raised texture can be a horizontal strip (parallel to the boundary line between the display area 110 and the folding area 120, as shown in FIG. Figure 5 As shown), it can be a longitudinal strip, or a combination of the two.

[0076] In another preferred embodiment, the raised texture is circular, and the schematic diagram of the circular raised texture structure is as shown in Figure 6 As shown, the diameter of the circular raised texture is 0.01-1 mm, and the distance between two adjacent circular raised textures is 0.005-1 mm;

[0077] In another preferred embodiment, the raised texture is dart-shaped, and the schematic diagram of the dart-shaped raised texture structure is as shown in Figure 7 shown.

[0078] Example 1

[0079] A flexible cover window, the cross-sectional structure diagram of which is as follows Figure 4 As shown, the planar structure diagram is as follows Figure 5 As shown, a glass substrate 100 is included, a display area 110 and a folding area 120 are provided on the glass substrate 100, and the folding area 120 is located in the middle of the display area 110, the thickness of the glass substrate of the display area 110 is 100 μm, and the thickness of the glass substrate of the folding area 120 is 30 μm;

[0080] The folding area 120 has a micro-texture structure, which includes a plurality of transverse strip-shaped raised textures, each of which has a raised height of about 25 μm, and a distance between two adjacent strip-shaped raised textures is 0.5 mm.

[0081] The method for preparing the flexible cover window provided in this embodiment comprises the following steps:

[0082] (1) using hydrofluoric acid to perform double-sided spray etching on the glass substrate to reduce the thickness of the glass substrate to 200 μm, completing the first thinning, and then performing laser cutting on the glass substrate after the first thinning, and attaching a UV acid-proof film to one side of the surface of the laser-cut glass substrate to obtain a glass substrate with a UV acid-proof film;

[0083] (2) bonding one side of the glass substrate with the UV acid-proof film obtained in step (1) with an acid-resistant liner, and then immersing one end of the glass substrate bonded with the acid-resistant liner in an acid solution (comprising hydrofluoric acid and nitric acid in a mass ratio of 1:1) in a direction parallel to the bonding line, wherein the depth of immersion in the acid solution exceeds one-half of the length of the target glass substrate in the direction parallel to the bonding line, so that the center line of the glass substrate is 5 mm below the position of the acid liquid surface, and then taking it out, and then immersing the other end of the glass substrate bonded with the acid-resistant liner in the acid solution in the same direction parallel to the bonding line, wherein the depth of immersion also exceeds one-half of the length of the target glass substrate in the direction parallel to the bonding line, and similarly the center line of the glass substrate is 5 mm below the position of the acid liquid surface, and then taking it out, thereby obtaining a target glass substrate including a display area and a folding area, and completing the second thinning;

[0084] (3) The target glass substrate including the display area and the folding area obtained in step (2) is coated with protective oil according to the positions that do not need to be etched in the desired micro-texture structure, and is thinned by a third yellow light etching to form a transverse strip-shaped raised micro-texture in the folding area, and the UV acid-proof film is removed. After strengthening and coating, the flexible cover window is obtained.

[0085] Example 2

[0086] A flexible cover window comprises a glass substrate. A display area and a folding area are arranged on the glass substrate. The folding area is located in the middle of the display area. The thickness of the glass substrate in the display area is 70 μm, and the thickness of the glass substrate in the folding area is 25 μm. Other structures, parameters and preparation methods are all referred to Example 1.

[0087] Example 3

[0088] A flexible cover window comprises a glass substrate. A display area and a folding area are arranged on the glass substrate. The folding area is located in the middle of the display area. The thickness of the glass substrate in the display area is 70 μm, and the thickness of the glass substrate in the folding area is 30 μm. Other structures, parameters and preparation methods are all referred to Example 1.

[0089] Example 4

[0090] A flexible cover window comprises a glass substrate. A display area and a folding area are arranged on the glass substrate. The folding area is located in the middle of the display area. The thickness of the glass substrate in the display area is 150 μm, and the thickness of the glass substrate in the folding area is 25 μm. Other structures, parameters and preparation methods are all referred to Example 1.

[0091] Example 5

[0092] A flexible cover window comprises a glass substrate. A display area and a folding area are arranged on the glass substrate. The folding area is located in the middle of the display area. The thickness of the glass substrate in the display area is 150 μm, and the thickness of the glass substrate in the folding area is 30 μm. Other structures, parameters and preparation methods are all referred to Example 1.

[0093] Performance Testing:

[0094] (1) Pen-dropping performance: The product is coated with OCA+PET film on both sides. A M&G signature pen (pen specification: 12.8g / 0.5mm) is dropped vertically, and the pen tip hits the glass. The highest pen-dropping height without breaking the glass is used to evaluate the pen-dropping performance of the product.

[0095] (2) Folding characteristics: Fold the glass in half in a way that simulates turning a book. If the product is not damaged, it is considered OK. The folding performance is evaluated based on the product’s folding radius (the smaller the better) and the number of folds (the more the better).

[0096] The flexible cover window provided in Example 1 was tested according to the above test method, and the test results are shown in Table 1:

[0097] Table 1

[0098]

[0099] According to the data in Table 1, we can see that:

[0100] The flexible cover window and the display area provided by the present invention have a maximum pen-falling performance of >50 μm without damage. According to the data of Examples 1 to 5, it can be seen that as the thickness of the display area increases, the pen-falling performance of the display area becomes better, and the folding characteristics can also reach the folding level of conventional UTG products.

[0101] The applicant declares that the present invention illustrates a flexible cover window and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a flexible cover window, characterized in that: The preparation method comprises the following steps: (1) performing first thinning, cutting, and single-side protection on the glass substrate in sequence to obtain a glass substrate with a protective layer; (2) laminating one side surface of the protective layer of the glass substrate with the protective layer obtained in step (1) to a backing plate, and immersing the glass substrate in an acid solution for a second thinning to obtain a glass substrate including a display area and a folding area; (3) The folding area of ​​the glass substrate including the display area and the folding area obtained in step (2) is thinned for a third time to form a micro texture in the folding area, and after removing the protective layer, the folding area is strengthened and coated to obtain the flexible cover window.

2. The preparation method according to claim 1, characterized in that: The method of the first thinning in step (1) is specifically: using hydrofluoric acid to perform double-sided spray etching on the initial glass substrate to complete the first thinning; Preferably, the thickness of the glass substrate after the first thinning in step (1) is 100 to 300 μm; Preferably, the cutting in step (1) is laser cutting and / or glass knife cutting; Preferably, the single-sided protection in step (1) comprises single-sided UV acid-proof film, single-sided silk-screen ink or single-sided spray photoresist.

3. The preparation method according to claim 1 or 2, characterized in that: The lining board in step (2) is an acid-resistant lining board; Preferably, the specific method of the second thinning in step (2) is: immersing one end of the glass substrate bonded with the liner into an acid solution along a direction parallel to the bonding line, taking it out, and then immersing the other end of the glass substrate bonded with the liner into the acid solution again along a direction parallel to the bonding line, taking it out again, to obtain a glass substrate including a display area and a folding area, and completing the second thinning; Preferably, the glass substrate bonded with the backing plate is etched by the acid solution at a rate of 1 to 5 μm / min; Preferably, the acid solution comprises hydrofluoric acid; Preferably, the acid solution further comprises any one of nitric acid, sulfuric acid or hydrochloric acid or a combination of at least two thereof; Preferably, the depth of the two immersions in the acid solution exceeds half of the length of the glass substrate in the direction parallel to the bonding line.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The third thinning in step (3) is yellow light etching thinning; Preferably, the strengthening in step (3) is potassium nitrate strengthening.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) using hydrofluoric acid to perform double-sided spray etching on the glass substrate to reduce the thickness of the glass substrate to a desired thickness of 100 to 300 μm, completing the first thinning, and then performing laser cutting and / or glass knife cutting on the glass substrate after the first thinning, and performing single-sided protection on one side of the surface of the cut glass substrate to obtain a glass substrate with a protective layer; (2) bonding one side of the glass substrate with the protective layer obtained in step (1) to an acid-resistant backing plate, and then immersing one end of the glass substrate with the acid-resistant backing plate in an acid solution along a direction parallel to the bonding line, the immersion depth exceeding half of the length of the glass substrate parallel to the bonding line, taking it out, and then immersing the other end of the glass substrate with the acid-resistant backing plate in the acid solution again along a direction parallel to the bonding line, the immersion depth also exceeding half of the length of the glass substrate parallel to the bonding line, and taking it out again, completing the second thinning, and obtaining a glass substrate including a display area and a folding area; (3) The folding area of ​​the glass substrate including the display area and the folding area obtained in step (2) is subjected to a third yellow light etching thinning to form a micro texture in the folding area of ​​the glass substrate, the protective layer is removed, and potassium nitrate strengthening and coating are performed to obtain the flexible cover window.

6. A flexible cover window, characterized in that: The flexible cover window is prepared by the preparation method according to any one of claims 1 to 5.

7. The flexible cover window according to claim 6, characterized in that: The flexible cover window includes a glass substrate; A display area and a folding area are provided on the glass substrate, wherein the folding area is located in the middle of the display area and is thinner than the display area; The folding area has a micro-texture structure, and the micro-texture structure includes a plurality of raised textures. The shapes of the raised textures are regular shapes, irregular shapes, or a combination of regular shapes and irregular shapes.

8. The flexible cover window according to claim 6 or 7, characterized in that: The thickness of the glass substrate in the display area is 70 to 200 μm; Preferably, the thickness of the glass substrate in the folding area is 25-50 μm.

9. The flexible cover window according to any one of claims 6 to 8, characterized in that: The convex texture has a convex height of 5 to 50 μm; Preferably, the distance between two adjacent raised textures is 0.005 to 1 mm; Preferably, the regular shape is an axisymmetric regular shape; Preferably, the axisymmetric regular shape is a bar, a sphere, a racetrack, a hexagon or a five-pointed star; Preferably, the raised texture is strip-shaped, the width of the strip-shaped raised texture is 0.01 to 1 mm, and the distance between two adjacent strip-shaped raised textures is 0.01 to 1 mm; Preferably, the raised texture is circular, the diameter of the circular raised texture is 0.01 to 1 mm, and the distance between two adjacent circular raised textures is 0.005 to 1 mm; Preferably, the irregular shape includes a dart shape or an I-shape; Preferably, the convex height of the convex texture is 5 to 50 μm.

10. Use of the flexible cover window according to any one of claims 6 to 9 in a flexible display.

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