Etching solution, glass cover plate, preparation method of glass cover plate, flexible display screen and electronic equipment

Abstract

The invention provides a glass etching solution, a glass cover plate, a preparation method of the glass cover plate, a flexible display screen and electronic equipment. The glass etching liquid provided by the embodiment of the invention comprises the following components in percentage by mass: 30-50% of hydrofluoric acid; 10% to 30% of sulfuric acid; 5% to 20% of nitric acid; and 2% to 8% of oxalic acid. When the glass etching liquid provided by the embodiment of the invention is used for thinning and etching the glass substrate, the surface of the etched glass substrate is free of crystal points, flow mark lines and heterochromatic points, and the surface of the thinned glass substrate has better smoothness and lower roughness, so that the glass substrate has higher light transmittance and appearance effect.

Description

Technical Field

[0001] The present application relates to the field of electronics, and in particular to an etching liquid, a glass cover plate and a preparation method thereof, a flexible display screen and an electronic device. Background Art

[0002] With the popularization and promotion of folding screen electronic devices (such as mobile phones), major electronic equipment manufacturers have launched their own folding screen electronic devices. Polyimide film (CPI) can be used as a glass cover for the flexible screen of folding screen electronic devices. However, the flexible screen with polyimide as the glass cover is prone to scratches, poor touch feel, low light transmittance, easy aging and other defects. When the thickness of ultra-thin flexible glass (UFG, Ultra Flexible Glass) is thinned to a certain extent, the bending radius of the glass screen can reach the millimeter level. The thinned glass cover has high bending performance and strength. It can be applied to flexible screens and can be bent more than 200,000 times, so that there is no obvious crease when the flexible screen switches from the folded state to the full-screen unfolded state. However, the thickness of the flexible glass plate produced by the glass manufacturer is still relatively thick, and its bending performance is difficult to meet the requirements of the flexible screen. It also needs to be further thinned to achieve the purpose of reducing the folding radius. However, the current process cost of preparing ultra-thin glass plates for flexible screens is too high. Summary of the invention

[0003] In view of the above problems, an embodiment of the present application provides a glass etching liquid, which, when used to thin and etch a glass substrate, can make the surface of the etched glass substrate free of crystal points, flow lines and discolored points, so that the surface of the thinned glass substrate has better smoothness and lower roughness, thereby having higher light transmittance and appearance effect.

[0004] In a first aspect, an embodiment of the present application provides a glass etching solution, wherein the glass etching solution comprises, by mass fraction:

[0005] 30% to 50% hydrofluoric acid;

[0006] 10% to 30% sulfuric acid;

[0007] 5% to 20% nitric acid; and

[0008] 2% to 8% oxalic acid.

[0009] A second aspect of the present application provides a method for preparing a glass cover plate, which includes:

[0010] providing a glass substrate; and

[0011] The glass substrate is immersed in a glass etching solution for etching to obtain a glass cover plate, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid and 2% to 8% oxalic acid.

[0012] A third aspect of the present application provides a glass cover plate, wherein the glass cover plate is obtained by etching a glass substrate with a glass etching solution, and the glass etching solution includes, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid and 2% to 8% oxalic acid.

[0013] A fourth aspect of the present application provides a glass cover plate, wherein a thickness h of the glass cover plate is in the range of 10 μm≤h≤60 μm; and a surface roughness Ra of the glass cover plate is in the range of 0.02 μm≤Ra≤0.06 μm.

[0014] A fifth aspect of the present application provides a flexible display screen, comprising:

[0015] Display layer; and

[0016] The glass cover plate described in the embodiment of the present application is stacked with the display layer to support and protect the display layer.

[0017] A sixth aspect of the present application provides a foldable electronic device, comprising:

[0018] The flexible display screen described in the embodiment of the present application;

[0019] a foldable mechanism, the foldable mechanism being used to carry the flexible display screen and to drive the flexible display screen to be folded or flattened, wherein the glass cover plate of the flexible display screen is farther away from the foldable mechanism than the display layer; and

[0020] A processor is electrically connected to the flexible display screen and is used to control the display screen to display.

[0021] The glass etching liquid of the embodiment of the present application can be used to etch and thin the glass substrate. When applied to the etching of the glass substrate, the surface of the etched glass substrate can be free of crystal points, flow lines and heterochromatic points, so that the surface of the thinned glass substrate has better smoothness and lower roughness, thereby having higher light transmittance and appearance effect. The ultra-thin glass obtained by etching in this application has better bending performance and a smaller bending radius. When applied to a flexible display screen, the ultra-thin glass is not easy to produce creases due to frequent folding, shattering or breaking during the folding and flattening of the flexible display screen, so that the flexible display screen has no obvious creases. Furthermore, the glass etching liquid of the embodiment of the present application has a lower cost when used to etch and thin the glass substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It is a schematic flow chart of a method for preparing a glass cover plate according to an embodiment of the present application.

[0024] Figure 2 It is a schematic flow chart of a method for preparing a glass cover plate according to another embodiment of the present application.

[0025] Figure 3 It is a schematic diagram of the arrangement and distribution of the bubbling tubes according to an embodiment of the present application.

[0026] Figure 4 It is a schematic diagram of the structure of a bubbling tube according to an embodiment of the present application.

[0027] Figure 5 yes Figure 4 Enlarged view of the dashed box I in the middle.

[0028] Figure 6 FIG. 4 is a flow chart of a method for preparing a glass cover plate according to another embodiment of the present application.

[0029] Figure 7 This application Figure 6 A structural schematic diagram of the preparation process of the glass cover plate of the embodiment.

[0030] Figure 8 Schematic diagram of the structure of a glass cover according to an embodiment of the present application.

[0031] Fig. 9 Schematic diagram of the structure of a glass cover plate according to another embodiment of the present application.

[0032] Fig.10 This is an electron microscope photograph of the glass substrate (640 times).

[0033] Fig.11 This is an electron microscope photograph (640 times) of the glass cover plate of Example 1.

[0034] Fig.12 This is an electron microscope photograph (640 times) of the glass cover plate of Example 2.

[0035] Fig.13 This is an electron microscope photograph (640 times) of the glass cover plate of Example 3.

[0036] Fig.14 It is a structural schematic diagram of a flexible display screen according to an embodiment of the present application.

[0037] Fig.15 It is a schematic structural diagram of a foldable electronic device in a flattened state according to an embodiment of the present application.

[0038] Fig.16 It is a schematic structural diagram of a foldable electronic device in a folded state according to an embodiment of the present application.

[0039] Fig.17 It is a circuit block diagram of an electronic device according to an embodiment of the present application.

[0040] Fig.18 yes Fig.16 Enlarged view of dashed box II.

[0041] Description of reference numerals:

[0042] 400-glass cover plate, 410-first plane portion, 420-bending portion, 430-second plane portion, 400a-glass substrate, 400b-intermediate cover plate, 420b-connecting portion, 10'-first protective layer, 30'-second protective layer, 200a-bubble tube, 210a-bubble hole, 500-flexible display screen, 510-display layer, 600-electronic device, 610-foldable mechanism, 611-first supporting member, 613-connecting axis, 615-second supporting member, 630-processor, 650-memory, 670-camera module. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0045] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0046] It should be noted that, for the convenience of explanation, in the embodiments of the present application, the same figure marks represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0047] With the popularization and promotion of folding screen electronic devices (such as mobile phones), major electronic equipment manufacturers have launched their own folding screen electronic devices. Polyimide film (CPI) can be used as a protective layer for the flexible screen of folding screen electronic devices. However, the flexible screen with polyimide as a protective layer is prone to scratches, poor touch feel, low light transmittance, easy aging and other defects. When the thickness of ultra-thin flexible glass (UFG, Ultra Flexible Glass) is thinned to a certain extent, the bending radius of the glass screen can reach the millimeter level. The thinned glass cover has high bending performance and strength. It can be used for flexible screens to achieve more than 200,000 bends, so that the flexible screen switches from the folded state to the full-screen unfolded state without obvious creases. However, the thickness of the flexible glass plates produced by glass manufacturers is still relatively thick (generally 0.12mm to 0.18mm), and the bending performance is difficult to meet the requirements of flexible screens. It needs to be further thinned to achieve the purpose of reducing the bending radius. The thinning of flexible glass plates produced by glass manufacturers can be carried out by mechanical grinding or etching with etching liquid. However, the cost of mechanical grinding is too high. The ultra-thin glass surface produced by etching with existing etching liquids has crystal points, flow marks or discolored points, which affect the display quality of the flexible screen.

[0048] In view of this, an embodiment of the present application provides a glass etching liquid, which can be used for thinning flexible glass, and the surface roughness of the produced flexible glass is low, and there are no crystal points, flow lines and heterochromatic points on the surface.

[0049] An embodiment of the present application provides a glass etching solution, which includes, by mass fraction, 30% to 50% of hydrofluoric acid, 10% to 30% of sulfuric acid, 5% to 20% of nitric acid, and 2% to 8% of oxalic acid.

[0050] In the embodiments of the present application, when a numerical value range from a to b is involved, unless otherwise specified, it means that the numerical value can be any numerical value between a and b, including the endpoint numerical value a and the endpoint numerical value b.

[0051] The glass etching solution of the embodiment of the present application can be used to etch and thin a glass substrate. The glass substrate can be, but is not limited to, silicate glass, high alumina silicate glass (such as Corning high alumina silicate glass), quartz glass, soda lime glass, fluoride glass, etc. It can be understood that the glass etching solution of the present application also includes water.

[0052] Specifically, the mass fraction of hydrofluoric acid in the glass etching solution of the present application can be, but is not limited to, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, etc. If the mass fraction of hydrofluoric acid in the glass etching solution is too low, the etching speed of the glass etching solution on the glass substrate will be affected, and the etching efficiency will be reduced; the higher the mass fraction of hydrofluoric acid in the glass etching solution, the higher the etching speed of the glass substrate. However, when the mass fraction of hydrofluoric acid in the glass etching solution is too high, it is easy to cause flow marks on the surface of the etched glass substrate, affecting the appearance of the product.

[0053] When the glass etching liquid of the present application is used to etch glass, the hydrofluoric acid in the glass etching liquid plays a leading role in the erosion of the silicon dioxide network skeleton in the glass. Specifically, the hydrofluoric acid provides hydrogen ions to replace the metal cations in the glass to generate a silica gel layer, and at the same time provides fluorine ions to erode the silicon dioxide skeleton in the glass to form a fluorosilicate etching particle layer, which plays a major etching role.

[0054] Specifically, the mass fraction of sulfuric acid in the glass etching solution of the present application can be, but is not limited to, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc. If the mass fraction of sulfuric acid in the glass etching solution is too low, the etching speed of the glass etching solution on the glass substrate will be affected, and the etching efficiency will be reduced; the higher the mass fraction of sulfuric acid in the glass etching solution, the higher the etching speed on the glass substrate. However, when the mass fraction of sulfuric acid in the glass etching solution is too high, it is easy to cause flow marks on the surface of the etched glass substrate, affecting the appearance of the product.

[0055] Specifically, the mass fraction of nitric acid in the glass etching solution of the present application can be, but is not limited to, 5%, 7%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, etc. If the mass fraction of nitric acid in the glass etching solution is too low, the etching speed of the glass etching solution on the glass substrate will be affected, and the etching efficiency will be reduced; the higher the mass fraction of nitric acid in the glass etching solution, the higher the etching speed of the glass substrate. However, when the mass fraction of nitric acid in the glass etching solution is too high, it is easy to cause flow marks to appear on the surface of the etched glass substrate, affecting the appearance of the product.

[0056] Specifically, the mass fraction of oxalic acid in the glass etching solution of the present application can be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc. If the mass fraction of oxalic acid in the glass etching solution is too low, the etching speed of the glass etching solution on the glass substrate will be affected, and the etching efficiency will be reduced; the higher the mass fraction of oxalic acid in the glass etching solution, the higher the etching speed on the glass substrate. However, when the mass fraction of oxalic acid in the glass etching solution is too high, it is easy to cause flow marks on the surface of the etched glass substrate, affecting the appearance of the product.

[0057] Sulfuric acid, nitric acid and oxalic acid can provide hydrogen ions, ensuring that the hydrogen ion concentration in the glass etching solution is in a stable state of high concentration during the reaction process (i.e., during the glass etching process), replacing the metal cations in the glass to generate a silica gel layer, providing basic conditions for fluorine ions to erode the skeleton in the glass; at the same time, the mixed use of multiple acid solutions can give full play to the mixed acid effect of the thinning etching solution, achieve the purpose of uniform thinning etching, and ensure that the surface of the etched glass has no defects such as crystal points, flow lines, and heterochromatic points, so that the surface of the glass cover plate after etching with the glass etching solution has no crystal points, flow lines, and heterochromatic points, has lower roughness, and better appearance. The synergistic effect of sulfuric acid, nitric acid, and oxalic acid can affect the dissolution of hydrofluoric acid on glass, and play a role in compatibility. The principle is that various silicates are formed by complex chemical reactions of sulfate ions, nitrate ions, oxalate ions, etc. on the surface of the glass substrate. Due to their inherent characteristics, they change the solubility of various silicates through hydrogen bonding to achieve a natural transition etching effect on the surface of the glass substrate.

[0058] The glass etching liquid of the embodiment of the present application can be used to etch and thin the glass substrate. When applied to the etching of the glass substrate, the surface of the etched glass substrate can be free of crystal points, flow lines and heterochromatic points, so that the surface of the thinned glass substrate has better smoothness and lower roughness, thereby having higher light transmittance and appearance effect. The ultra-thin glass obtained by etching in this application has better bending performance and a smaller bending radius. When applied to a flexible display screen, the ultra-thin glass is not easy to produce creases due to frequent folding, shattering or breaking during the folding and flattening of the flexible display screen, so that the flexible display screen has no obvious creases. Furthermore, the glass etching liquid of the embodiment of the present application has a lower cost when used to etch and thin the glass substrate.

[0059] In some embodiments, the glass etching solution includes, by mass fraction, 36% to 42% hydrofluoric acid, 18% to 23% sulfuric acid, 10% to 15% nitric acid, and 4% to 6% oxalic acid. When the glass etching solution includes acids in these proportions, the synergistic effect of the three acids, sulfuric acid, nitric acid, and oxalic acid, can better affect the dissolution of the glass by hydrofluoric acid, and play a better role in compatibility. When applied to etching of a glass substrate, the etching effect of the natural transition of the surface of the glass substrate can be better achieved, and the surface of the etched glass substrate can be free of crystal points, flow lines, and heterochromatic points, so that the surface of the thinned glass substrate has better smoothness and lower roughness, thereby having higher light transmittance and appearance effect.

[0060] In some embodiments, the glass etching solution of the present application further comprises borax, and the mass fraction of the borax ranges from 0.2% to 0.5%. It can be understood that in this embodiment, the glass etching solution comprises 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, 2% to 8% oxalic acid and 0.2% to 0.5% borax, and the balance is water.

[0061] Specifically, the mass fraction of borax in the glass etching solution can be, but is not limited to, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc. If the mass fraction of borax is too small, it is not conducive to the wettability of the glass etching solution and the surface of the glass substrate; if the mass fraction of borax is too large, the improvement of the wettability of the glass etching solution and the surface of the glass substrate is limited, but it is easy to produce secondary problems and increase the probability of surface defects of the glass substrate after etching.

[0062] In this embodiment, borax is added to the glass etching solution. Borax is introduced as a surfactant. When glass etching is performed, the wettability of the glass etching solution to the surface of the glass substrate can be improved, thereby reducing the probability of leaking etching on the surface of the glass substrate (i.e., reducing the probability of leaking and fogging), making the etching of the surface of the glass substrate more complete and uniform, and the etched glass cover plate has higher light transmittance and better appearance.

[0063] In some embodiments, the glass etching solution of the present application further comprises ammonium bifluoride, and the mass fraction of the ammonium bifluoride ranges from 1% to 3%. It can be understood that in the present embodiment, the glass etching solution comprises 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, 2% to 8% oxalic acid, 0.2% to 0.5% borax and 1% to 3% ammonium bifluoride, and the balance is water.

[0064] Specifically, the mass fraction of ammonium bifluoride in the glass etching solution can be, but is not limited to, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, etc. Since glass etching is carried out in an assembly line, when the mass fraction of ammonium bifluoride is too low, when etching to a certain extent or after a period of time, it is easy to cause flow marks to appear on the surface of the etched glass. If the mass fraction of ammonium bifluoride is too high, the light transmittance of the surface of the etched glass will be seriously reduced, affecting the smoothness and flatness of the glass surface. When the mass fraction of ammonium bifluoride in the glass etching solution is 1% to 3%, after etching the glass substrate, the surface of the etched glass substrate has higher smoothness and flatness (i.e., lower roughness), and can better avoid the appearance of flow marks. Compared with other fluoride salts, adding ammonium bifluoride can make the glass etching solution have a better thinning effect.

[0065] In this embodiment, by adding ammonium bifluoride to the glass etching solution, the ammonium bifluoride can provide fluoride ions, timely replenish the consumption of fluoride ions in the glass thinning and etching process, ensure the long-lasting and stable efficacy of the glass etching solution, and thus ensure that the surface of the glass cover plate obtained by etching and thinning is more uniform and smoother.

[0066] In some embodiments, the glass etching solution of the present application further comprises polyacrylamide, and the mass fraction of the polyacrylamide ranges from 0.2% to 0.5%. It is understandable that in the present embodiment, the glass etching solution comprises 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, 2% to 8% oxalic acid, 0.2% to 0.5% borax, 0.2% to 0.5% polyacrylamide and 1% to 3% ammonium bifluoride, and the balance is water.

[0067] Specifically, the mass fraction of polyacrylamide in the glass etching solution can be, but is not limited to, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc. If the mass fraction of polyacrylamide is too small, the flocculation effect is not good; if the mass fraction of polyacrylamide is too large, the improvement of the flocculation effect of glass sand is limited, but secondary problems are likely to occur, increasing the probability of surface defects of the glass substrate after etching.

[0068] Since a large amount of micron-sized glass sand will be generated during the glass thinning and etching process, these fine glass sands are always suspended in the glass etching solution during etching. When these glass sands reach a certain concentration, they will affect the effect of glass thinning and etching. Therefore, a certain amount of polyacrylamide is added to the glass etching solution. The flocculation effect of polyacrylamide is used to make these suspended glass sands settle down as soon as possible during the interval of stopping glass thinning and etching, and they are regularly removed to ensure the stability of the efficacy of the glass etching solution. If the mass fraction of polyacrylamide is too low, the flocculation effect on the glass sand is poor, or even no flocculation effect is achieved. If the mass fraction of polyacrylamide is too high, the flocculation effect on the glass sand is limited, but the preparation cost of the glass etching solution is increased.

[0069] The glass etching liquid of the embodiment of the present application is used to etch the glass substrate, and the speed of thinning the glass substrate can be 1μm / min to 5μm / min. In other words, the etching speed of the glass substrate by the glass etching liquid is 1μm / min to 5μm / min. Specifically, when etching, the speed of thinning the glass substrate can be but not limited to 1μm / min, 2μm / min, 3μm / min, 4μm / min, 5μm / min, etc. If the speed of thinning the glass substrate is too slow, the slower the etching speed, the production efficiency of the glass cover plate will be affected. If the speed of thinning the glass substrate is too slow, the rate at which the glass etching liquid reacts with the glass substrate is too fast, and it is easy to leave defects on the surface of the glass substrate, affecting the light transmittance of the obtained glass cover plate and the smoothness and flatness of the surface.

[0070] See also Figure 1 The present application also provides a method for preparing a glass cover plate, which comprises:

[0071] S101, providing a glass substrate; and

[0072] Optionally, the glass substrate may be, but is not limited to, silicate glass, high alumina silicate glass (such as Corning high alumina silicate glass), quartz glass, soda lime glass, fluoride glass, etc. It is understandable that the glass etching solution of the present application also includes water.

[0073] Optionally, the glass cover plate may be, but is not limited to, ultra-thin glass or ultra-flexible glass.

[0074] S102, immersing the glass substrate in a glass etching solution for etching to obtain a glass cover plate, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, and 2% to 8% oxalic acid.

[0075] Optionally, a glass etching liquid is poured into an etching tank, and a glass substrate is immersed in the etching tank, and the glass etching liquid is made to cover the glass substrate, so as to perform thinning and etching on the glass substrate to obtain a glass cover plate.

[0076] For a detailed description of the glass etching liquid, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0077] The method for preparing the glass cover plate of the embodiment of the present application can be applied to prepare the glass cover plate of a flexible display screen, which is used to support and protect the display layer of the flexible display screen. The glass cover plate of the embodiment of the present application can be a flexible ultra-thin glass plate.

[0078] The preparation method of the glass cover plate of the embodiment of the present application adopts glass etching liquid to thin and etch the glass substrate, and the glass etching liquid includes hydrofluoric acid, sulfuric acid, nitric acid and oxalic acid. During etching, the hydrofluoric acid in the glass etching liquid plays a leading role in the erosion of the silicon dioxide network skeleton in the glass substrate. The hydrofluoric acid provides hydrogen ions to replace the metal cations in the glass substrate to generate a silica gel layer, and at the same time provides fluorine ions to erode the silicon dioxide skeleton in the glass substrate to form a fluorosilicate etching particle layer, which plays a major etching role. Sulfuric acid, nitric acid and oxalic acid can provide hydrogen ions, ensuring that the hydrogen ion concentration in the glass etching solution is in a stable state of high concentration during the reaction process (i.e., during the etching of the glass substrate), replacing the metal cations in the glass substrate to generate a silica gel layer, providing basic conditions for fluorine ions to erode the skeleton in the glass substrate; at the same time, the mixed use of multiple acid solutions can give full play to the mixed acid effect of the thinning etching solution, achieve the purpose of uniform thinning etching, and ensure that the surface of the etched glass substrate (i.e., the glass cover plate) has no defects such as crystal points, flow marks, and discoloration points, so that the surface of the glass cover plate after etching with the glass etching solution has no crystal points, flow marks, and discoloration points, has a lower roughness, and has a better appearance effect. In addition, compared with the glass cover plate made by the mechanical grinding process, the glass cover plate made by the embodiment of the present application has a lower cost.

[0079] See also Figure 2 The present application also provides a method for preparing a glass cover plate, which comprises:

[0080] S201, providing a glass substrate;

[0081] For a detailed description of the glass substrate, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0082] S202, pre-treating the glass substrate to remove pollutants on the surface of the glass substrate; and

[0083] Optionally, a mixed aqueous solution of sulfuric acid and hydrofluoric acid (i.e., a pretreatment solution) is used to pretreat the surface of the glass substrate, and the surface of the glass substrate is cleaned with pure water to remove pollutants such as organic matter, oil stains, and dust, so that the surface of the glass substrate is free of foreign matter, thereby preventing foreign matter on the surface of the glass substrate from affecting the etching effect of the glass substrate, causing etching defects, and affecting the smoothness and flatness of the surface of the manufactured glass cover plate.

[0084] Optionally, the mass fraction of sulfuric acid in the pretreatment solution is in the range of 5% to 10%, and the mass fraction of hydrofluoric acid in the pretreatment solution is in the range of 5% to 10%. The concentrations of sulfuric acid and hydrofluoric acid in the pretreatment solution can be adjusted according to the type and cleanliness of the glass substrate, and are not specifically limited in this application.

[0085] S203, immersing the pretreated glass substrate into a glass etching solution for etching to obtain a glass cover plate, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, and 2% to 8% oxalic acid.

[0086] Optionally, pour the prepared glass etching solution into the etching tank, and make the temperature T of the glass etching solution in the range of 15°C≤T≤25°C; immerse the glass substrate in the glass etching solution so that the glass substrate is located at a depth of 100 mm to 150 mm below the liquid surface of the glass etching solution (i.e., the immersion depth is 100 mm to 150 mm), so as to ensure that the glass substrate is fully immersed in the glass etching solution, thereby etching the glass substrate to obtain a glass cover plate.

[0087] Optionally, the temperature T of the glass etching liquid may be, but is not limited to, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 23°C, 24°C, 25°C, etc. If the temperature of the glass etching liquid is too high, the reaction speed between the glass etching liquid and the glass substrate is reduced, that is, the etching speed is reduced, and the etching work efficiency is reduced; the increase in the temperature of the glass etching liquid can accelerate the etching speed of the glass etching liquid on the glass substrate, but when the temperature of the glass etching liquid is too high, it is easy to cause flow marks on the surface of the glass substrate, affecting the appearance of the prepared glass cover plate.

[0088] Optionally, the immersion depth of the glass substrate may be, but is not limited to, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, etc. The immersion depth of the glass substrate can be sufficient to ensure that the glass substrate is fully immersed in the glass etching solution, and this application does not make any specific restrictions.

[0089] Optionally, the etching time is 20 minutes to 80 minutes, and specifically, the etching time may be, but is not limited to, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, etc. The longer the etching time, the greater the thinning degree of the glass substrate. The etching time may be determined according to the thickness of the glass substrate to be thinned, and the present application does not make any specific limitation.

[0090] Optionally, during etching, the glass substrate is thinned at a speed of 1 μm / min to 5 μm / min. Specifically, during etching, the glass substrate is thinned at a speed of, but not limited to, 1 μm / min, 2 μm / min, 3 μm / min, 4 μm / min, 5 μm / min, etc. If the glass substrate is thinned too slowly, the etching speed will be slower, affecting the production efficiency of the glass cover plate. If the glass substrate is thinned too slowly, the rate at which the glass etching liquid reacts with the glass substrate will be too fast, easily leaving defects on the surface of the glass substrate, affecting the light transmittance and surface smoothness and flatness of the obtained glass cover plate.

[0091] In some embodiments, immersing the glass substrate in a glass etching solution for etching includes: immersing the glass substrate in a glass etching solution; and bubbling the glass etching solution.

[0092] Specifically, the prepared glass etching solution is poured into the etching tank, and a plurality of bubbling tubes 200a arranged at intervals are arranged in the etching tank (it can be understood that a bubbling device having bubbling tubes 200a arranged in an array can be used for bubbling, and the arrangement of the bubbling tubes 200a is as follows: Figure 3 As shown in the figure, the air flow (such as purified compressed air) is bubbled into the bubble tube 200a, so that the glass etching liquid produces a boiling effect, so that the glass etching liquid can evenly impact the surface of the glass substrate, so that the etching of the surface of the glass substrate is more uniform. Bubbling the glass etching liquid during the etching process can achieve stirring of the glass etching liquid, so that the glass etching liquid is always in a uniform state, and the etching effect of the glass etching liquid on each position of the glass substrate is more uniform.

[0093] See also Figure 4 and Figure 5Optionally, each of the bubbling tubes 200a has a plurality of bubbling holes 210a arranged at intervals, and the range of the aperture d of the bubbling holes 210a is: 0.3mm≤d≤0.6mm. Specifically, the aperture d of the bubbling hole 210a can be, but is not limited to, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, etc. If the aperture of the bubbling hole 210a is too small, it is easy to be blocked by the glass sand dropped from the glass substrate during the etching process; if the aperture of the bubbling hole 210a is too large, it is easy to cause the glass etching liquid to churn violently, resulting in excessive force of the glass sand impacting the surface of the glass substrate, and causing secondary defects on the surface of the obtained glass cover plate. When the aperture of the bubble hole 210a is in the range of 0.3 mm to 0.6 mm, it can prevent the bubble hole 210a from being blocked and avoid the glass etching liquid from churning violently, which causes the glass sand to impact the surface of the glass substrate with too much force, thereby causing secondary defects on the surface of the manufactured glass cover plate.

[0094] Optionally, the range of the spacing s between the two adjacent bubbling holes 210a on the same bubbling tube 200a is: 60mm≤s≤80mm. Specifically, the spacing s between the two adjacent bubbling holes 210a on the same bubbling tube 200a can be, but is not limited to, 60mm, 65mm, 70mm, 75mm, 80mm, etc. If the spacing between adjacent bubbling holes 210a is too small, it is easy to cause the glass etching liquid to churn violently, causing the glass sand to impact the surface of the glass substrate with excessive force, and causing secondary defects on the surface of the prepared glass cover plate. If the spacing between adjacent bubbling holes 210a is too large, the churning of the glass etching liquid is easy to be uneven, which easily causes uneven etching at different positions on the surface of the glass substrate, affecting the etching effect.

[0095] Optionally, the diameter D of each of the bubbling tubes 200a is in the range of 20mm≤D≤40mm. Specifically, the diameter D of each of the bubbling tubes 200a can be, but is not limited to, 20mm, 25mm, 30mm, 35mm, 40mm, etc. The diameter of the bubbling tube 200a is too small, the amount of airflow introduced is too small, and the bubbling of the glass etching liquid is not enough, which easily leads to uneven churning of the glass etching liquid, and easily makes the etching of different positions on the surface of the glass substrate uneven, affecting the etching effect. The diameter of the bubbling tube 200a is too large, and the volume occupied by the single bubbling tube 200a is too large, and the number of the bubbling tubes 200a that can be set is too small, which also easily leads to uneven churning of the glass etching liquid, and easily makes the etching of different positions on the surface of the glass substrate uneven, affecting the etching effect.

[0096] Optionally, when etching, a stable and continuous high-pressure airflow is introduced through the bubbling tube 200a. Optionally, the air pressure P of the airflow is 0.3Mpa to 0.8Mpa. Specifically, the air pressure P of the airflow can be, but is not limited to, 0.3Mpa, 0.4Mpa, 0.5Mpa, 0.6Mpa, 0.7Mpa, 0.8Mpa, etc. As the etching reaction proceeds, the concentration of effective substances in the glass etching solution near the position of the glass substrate will gradually decrease. If the air pressure of the airflow is too small, it will be difficult to achieve the purpose of the comparative etching solution and the reverse stirring, and the concentration of each position of the glass etching solution cannot be uniformly in a uniform state, affecting the smoothness and flatness of the surface of the glass cover plate obtained; if the air pressure of the airflow is too large, it is easy to cause the etching solution to churn violently, resulting in excessive force on the surface of the glass substrate to impact the glass sand, and secondary defects are produced on the surface of the obtained glass cover plate.

[0097] It should be noted that the method for preparing the glass cover plate of the embodiment of the present application can be used to prepare a glass cover plate with uniform thickness, or only a part of the glass substrate, such as the middle area, can be etched and thinned to prepare a glass cover plate with non-uniform thickness (i.e., unequal thickness).

[0098] See also Figure 6 and Figure 7 The embodiment of the present application further provides a method for preparing a glass cover plate 400, wherein the glass cover plate 400 comprises a first plane portion 410, a bending portion 420 and a second plane portion 430 connected in sequence, wherein the first plane portion 410 and the second plane portion 430 have equal thicknesses, and the thickness of the bending portion 420 is smaller than the thickness of the first plane portion 410 and smaller than the thickness of the second plane portion 430; the preparation method comprises:

[0099] S301, providing a glass substrate 400a;

[0100] S302, immersing the glass substrate 400a in a glass etching solution for etching to obtain an intermediate cover plate 400b, wherein the intermediate cover plate 400b includes a first plane portion 410, a connecting portion 420b and a second plane portion 430 connected in sequence, and the first plane portion 410, the connecting portion 420b and the second plane portion 430 are all of equal thickness; the glass etching solution includes, by mass fraction, 30% to 50% of hydrofluoric acid, 10% to 30% of sulfuric acid, 5% to 20% of nitric acid and 2% to 8% of oxalic acid;

[0101] For detailed descriptions of S301 and S302, please refer to the descriptions of the corresponding parts of S101 and S102, which will not be repeated here.

[0102] S303, a first protective layer 10' is disposed on one surface of the intermediate cover plate 400b, and a second protective layer 30' is disposed on another surface of the intermediate cover plate 400b away from the first protective layer 10', corresponding to the first plane portion 410 and the second plane portion 430; and

[0103] Optionally, a protective ink or photoresist mask layer or other film layer having an anti-etching effect in an etching solution may be disposed on the entire surface of one of the two opposite surfaces of the intermediate cover plate 400b as a first protective layer 10', and a protective ink or photoresist mask layer or other film layer having an anti-etching effect in an etching solution may be disposed on the other surface except for the connecting portion 420b as a second protective layer 30'. It can be understood that the first protective layer 10' and the second protective layer 30' will not be corroded by the glass etching solution, so that when the intermediate cover plate 400b is etched, only one surface of the connecting portion 420b will be etched, and thus it will continue to be thinned to obtain a glass cover plate 400 of unequal thickness.

[0104] It can be understood that the position of the second protective layer 30 ′ corresponding to the connecting portion 420 b is hollowed out.

[0105] Optionally, the photoresist mask layer may be a positive photoresist mask layer or a negative photoresist mask layer. Compared with the negative photoresist mask layer, the positive photoresist mask layer has higher precision.

[0106] S304 , immersing the intermediate cover plate 400 b provided with the first protective layer 10 ′ and the second protective layer 30 ′ into the glass etching solution for etching, so as to thin the connecting portion 420 b to form a bent portion 420 , thereby obtaining a glass cover plate 400 .

[0107] Optionally, the intermediate cover plate 400 b provided with the first protective layer 10 ′ and the second protective layer 30 ′ is immersed in the glass etching solution again for etching to thin the connecting portion 420 b so as to form a bending portion 420 .

[0108] It can be understood that the glass etching liquid in S302 and S304 can both be the glass etching liquid of the embodiment of the present application.

[0109] The bending portion 420 of the glass cover plate 400 obtained in this embodiment has a smaller thickness than the first planar portion 410 and the second planar portion 430, so that it has better bending performance and a better bending radius, and will not be damaged after more bending times. When applied to a flexible display screen, it is not easy to produce creases due to frequent folding, breakage or fracture during the folding and flattening process of the flexible display screen.

[0110] See also Figure 8The embodiment of the present application further provides a glass cover plate 400, wherein the glass cover plate 400 is obtained by etching a glass substrate 400a with a glass etching solution, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid, and 2% to 8% oxalic acid.

[0111] It can be understood that the glass cover plate 400 can be but is not limited to ultra-thin glass or ultra-flexible glass.

[0112] Optionally, when the glass cover plate 400 of the embodiment of the present application is bent, its bending radius is in the millimeter level, for example, the bending radius is 3 mm to 5 mm.

[0113] Optionally, the glass cover plate 400 of the embodiment of the present application may be prepared by using the preparation method of the above embodiment.

[0114] When the glass etching liquid of the present application is used to etch the glass, the hydrofluoric acid in the glass etching liquid plays a leading role in the erosion of the silicon dioxide network skeleton in the glass. Specifically, the hydrofluoric acid provides hydrogen ions to replace the metal cations in the glass to generate a silica gel layer, and provides fluorine ions to erode the silicon dioxide skeleton in the glass to form a fluorosilicate etching particle layer, which plays a major etching role. Sulfuric acid, nitric acid and oxalic acid can provide hydrogen ions to ensure that the hydrogen ion concentration in the glass etching liquid is in a stable state of higher concentration during the reaction process (i.e., during the glass etching process), and replaces the metal cations in the glass to generate a silica gel layer, providing basic conditions for fluorine ion erosion of the skeleton in the glass; at the same time, the mixed use of multiple acid solutions can give full play to the mixed acid effect of the thinning etching solution, achieve the purpose of uniform thinning etching, ensure that the surface of the etched glass has no crystal points, flow marks, heterochromatic spots and other defects, so that the surface of the glass cover plate after etching by the glass etching liquid has no crystal points, no flow marks and no heterochromatic spots, with lower roughness and better appearance.

[0115] The embodiment of the present application further provides a glass cover plate 400 , wherein the thickness h of the glass cover plate 400 is in the range of 10 μm≤h≤60 μm, and the surface roughness Ra of the glass cover plate 400 is in the range of 0.02 μm≤Ra≤0.06 μm.

[0116] The thickness h of the glass cover plate 400 is in the range of 10μm≤h≤60μm. Specifically, the thickness h of the glass cover plate 400 may be, but is not limited to, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, etc. When the thickness of the glass cover plate 400 is too thin, the mechanical strength of the glass cover plate 400 is reduced, making the glass cover plate 400 fragile after multiple foldings, and when applied to a flexible display screen, it is difficult to effectively protect the display layer of the flexible display screen; when the thickness of the glass cover plate 400 is too thick, the bending performance of the glass cover plate 400 is reduced, and the bending radius is difficult to reach the millimeter level. When applied to a flexible display screen, the bending performance of the flexible display screen is reduced and the thickness of the flexible display screen is increased.

[0117] The range of the surface roughness Ra of the glass cover plate 400 is 0.02μm≤Ra≤0.06μm. In other words, the range of the surface roughness Ra of the glass cover plate 400 is 20nm≤Ra≤60nm. Specifically, the roughness Ra of the glass cover plate 400 can be but is not limited to 0.02μm, 0.03μm, 0.04μm, 0.05μm, 0.06μm, etc. If the roughness of the glass cover plate 400 is too small, it is difficult for the etching process to achieve such a low roughness when the glass cover plate 400 is prepared by thinning and etching. If the roughness is too large, the transmittance of the glass cover plate 400 is affected. When applied to a flexible display screen, it affects the light output effect of the flexible display screen.

[0118] The glass cover plate 400 of the present embodiment can be obtained by etching a glass substrate 400 a using a glass etching solution.

[0119] The glass cover plate 400 of the embodiment of the present application has a thinner thickness, better bending performance and a smaller bending radius. When applied to a flexible display screen, the bending radius of the flexible display screen can reach the millimeter level when it is bent. It has good bending performance and strength, and can be bent more than 200,000 times without damage. In the process of folding and flattening the flexible display screen, it is not easy to produce creases due to frequent folding, breaking or fracture, so that the flexible display screen has no obvious creases. Furthermore, the glass cover plate 400 of the embodiment of the present application has a smaller surface roughness. When applied to a flexible display screen, it can make the flexible display screen have better flatness and will not affect the light emitting effect of the display layer of the flexible display screen.

[0120] The glass cover plate 400 of the embodiment of the present application can be applied to a flexible display screen to protect the display layer of the flexible display screen.

[0121] Optionally, the glass cover plate 400 of the embodiment of the present application may be prepared by using the preparation method of the above-mentioned embodiment of the present application.

[0122] The glass cover plate 400 of the embodiment of the present application is obtained by etching the glass substrate 400a with a glass etching solution. The obtained glass cover plate 400 has a thinner thickness, better bending performance and a smaller bending radius (the bending radius reaches the millimeter level). When applied to a flexible display screen, the bending radius of the flexible display screen can reach the millimeter level when it is bent. It has good bending performance and strength, and can be bent more than 200,000 times without damage. In the process of folding and flattening the flexible display screen, it is not easy to produce creases due to frequent folding, breaking or fracture. Furthermore, the glass cover plate 400 of the embodiment of the present application has a smaller surface roughness. When applied to a flexible display screen, it can make the flexible display screen have better flatness and will not affect the light emission effect of the display layer of the flexible display screen.

[0123] In some embodiments, the thickness of the glass cover 400 is uniform, such as Figure 8 shown.

[0124] See also Fig. 9 In other embodiments, the thickness of the glass cover plate 400 is uneven. The glass cover plate 400 includes a first plane portion 410, a bending portion 420 and a second plane portion 430 connected in sequence. The thickness of the first plane portion 410 and the second plane portion 430 are equal, and the thickness of the bending portion 420 is smaller than the thickness of the first plane portion 410 and smaller than the thickness of the second plane portion 430.

[0125] Optionally, the thickness of the first planar portion 410 is in a range of 20 μm to 40 μm, the thickness of the second planar portion 430 is in a range of 20 μm to 40 μm, and the thickness of the bent portion 420 is in a range of 10 μm to 20 μm.

[0126] In other embodiments, the thickness of the glass cover plate 400 is uneven. The glass cover plate 400 includes a first plane portion 410, a bending portion 420 and a second plane portion 430 connected in sequence. The thickness of the first plane portion 410 and the second plane portion 430 are equal. The thickness of the bending portion 420 is less than the thickness of the first plane portion 410 and less than the thickness of the second plane portion 430. The thickness of the connection between the bending portion 420 and the first plane portion 410 and the second plane portion 430 gradually transitions, that is, smoothly transitions. It can be understood that the thickness of the connection between the bending portion 420 and the first plane portion 410 gradually transitions to the thickness of the bending portion 420, and the thickness of the connection between the bending portion 420 and the second plane portion 430 gradually transitions to the thickness of the bending portion 420. In some embodiments, the glass etching solution of the present application also includes borax, and the mass fraction of the borax ranges from 0.2% to 0.5%. In this embodiment, borax is added to the glass etching solution. Borax is introduced as a surfactant. When glass etching is performed, the wettability between the glass etching solution and the surface of the glass substrate 400a can be improved, thereby reducing the probability of missed etching on the surface of the glass substrate 400a (i.e., reducing the probability of missed etching), making the etching of the surface of the glass substrate 400a more complete and more uniform, and the etched glass cover plate has higher light transmittance and better appearance.

[0127] In some embodiments, the glass etching solution of the present application also includes ammonium bifluoride, and the mass fraction of the ammonium bifluoride ranges from 1% to 3%. In the present embodiment, by adding ammonium bifluoride to the glass etching solution, ammonium bifluoride can provide fluoride ions, timely replenish the consumption of fluoride ions in the glass thinning and etching process, and ensure that the efficacy of the glass etching solution is long-lasting and stable, thereby ensuring that the surface of the glass cover plate obtained by etching and thinning is more uniform and smoother. Since the glass etching adopts an assembly line for etching, when the mass fraction of ammonium bifluoride is too low, when etching to a certain extent or after a period of time, it is easy to make the surface of the etched glass have flow marks. The mass fraction of ammonium bifluoride is too high, which will cause the light transmittance of the surface of the etched glass to drop seriously, affecting the smoothness and flatness of the glass surface. When the mass fraction of ammonium bifluoride in the glass etching solution is 1% to 3%, after etching the glass substrate 400a, the surface of the etched glass substrate 400a has higher smoothness and flatness (i.e., lower roughness), and can better avoid the appearance of flow marks.

[0128] In some embodiments, the glass etching liquid of the present application also includes polyacrylamide, and the mass fraction of the polyacrylamide ranges from 0.2% to 0.5%. Since a large amount of micron-sized glass sand is generated during the glass thinning and etching process, these fine glass sands are suspended in the glass etching liquid all the time during etching. When these glass sands reach a certain concentration, they will affect the effect of glass thinning and etching. Therefore, a certain amount of polyacrylamide is added to the glass etching liquid, and the flocculation effect of polyacrylamide is utilized. In the gap where the glass thinning and etching is stopped, these suspended glass sands are allowed to settle as soon as possible and are regularly removed to ensure that the efficacy of the glass etching liquid is stable. The mass fraction of polyacrylamide is too low, and the flocculation effect on the glass sand is poor, or even no flocculation effect is achieved. The mass fraction of polyacrylamide is too high, and the flocculation effect on the glass sand is limited, but the preparation cost of the glass etching liquid is increased.

[0129] For detailed description of other aspects of the glass etching liquid, please refer to the description of the corresponding parts of the above embodiments, which will not be repeated here.

[0130] The light transmittance of the glass cover plate 400 obtained by etching the glass substrate 400a with the glass etching solution of the embodiment of the application is reduced by less than or equal to 0.3% compared with the light transmittance of the glass substrate 400a. It can be understood that the difference between the light transmittance T0 of the glass substrate 400a and the light transmittance T1 of the glass cover plate 400 obtained by etching and thinning the glass substrate 400a is less than or equal to 0.3%, that is, T0-T1≤0.3%.

[0131] Optionally, the light transmittance of the glass cover plate 400 obtained by etching the glass substrate 400a with the glass etching solution of the embodiment of the application is 90% to 99%. Specifically, the light transmittance of the glass cover plate 400 can be, but is not limited to, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. The higher the light transmittance of the glass cover plate 400, when applied to a flexible display screen, the higher the light output rate of the flexible display screen, and the brighter the display brightness.

[0132] Optionally, the reflectivity of the glass cover plate 400 obtained by etching the glass substrate 400a with the glass etching solution of the embodiment of the application is 0.5% to 9.5%. Specifically, the reflectivity of the glass cover plate 400 can be but not limited to 0.5%, 1%, 3%, 5%, 7%, 8%, 9.5%, etc. The lower the reflectivity of the glass cover plate 400, the more beneficial it is to the light extraction efficiency of the display layer of the flexible display when applied to the flexible display.

[0133] Optionally, the haze of the glass cover plate 400 obtained by etching the glass substrate 400a using the glass etching liquid of the embodiment of the application is 0.03% to 0.06%. Specifically, the haze of the glass cover plate 400 can be but not limited to 0.03%, 0.04%, 0.05%, 0.06%. The lower the haze of the glass cover plate 400, the more beneficial it is to the light extraction efficiency of the display layer of the flexible display when applied to a flexible display. This shows that the glass cover plate 400 obtained by etching and thinning the glass substrate 400a using the glass etching liquid of the present application has a very low haze, a high light transmittance and a good surface smoothness.

[0134] Optionally, the glossiness of the glass cover plate 400 obtained by etching the glass substrate 400a with the glass etching solution of the embodiment of the application is 148Gu to 162Gu; specifically, the glossiness of the glass cover plate 400 can be but not limited to 148Gu, 150Gu, 153Gu, 155Gu, 158Gu, 160Gu, 162Gu, etc. The glass cover plate 400 of the embodiment of the present application has a high glossiness. The glossiness of the glass cover plate 400 will not only not decrease, but also slightly improve compared with the glossiness of the glass substrate 400a.

[0135] The glass etching liquid of the embodiment of the present application and the glass cover plate 400 made by using the glass etching liquid are further described below by way of specific embodiments.

[0136] Example 1

[0137] The glass cover plate 400 of this embodiment is prepared by the following steps:

[0138] 1) preparing a glass etching solution, which comprises, by mass fraction, 45% hydrofluoric acid, 15% sulfuric acid, 10% nitric acid, 5% oxalic acid, 2.5% ammonium bifluoride, 0.3% polyacrylamide, 0.2% borax and 22% water;

[0139] 2) Pre-treating the glass substrate 400 a (the thickness of the glass substrate 400 a is 120 μm) with sulfuric acid and hydrofluoric acid aqueous solutions, and then cleaning with pure water;

[0140] 3) placing the cleaned glass substrate 400a horizontally into a glass etching solution at a temperature of 20°C, with an immersion depth of 150mm;

[0141] 4) turning on the bubbling device for bubbling, and the bubbling etching time is 23.5 minutes; and

[0142] 5) After the set etching time is reached, the etched glass substrate 400a is taken out and cleaned with flowing pure water. After air drying, the desired glass cover plate 400 is obtained.

[0143] The glass cover plate 400 manufactured in this embodiment has a reduced thickness of 72 μm compared to the glass substrate 400 a .

[0144] Example 2

[0145] The glass cover plate 400 of this embodiment is prepared by the following steps:

[0146] 1) preparing a glass etching solution, which comprises, by mass fraction, 50% hydrofluoric acid, 10% sulfuric acid, 8% nitric acid, 3.5% oxalic acid, 3% ammonium bifluoride, 0.2% polyacrylamide, 0.3% borax and 25% water;

[0147] 2) Pre-treating the glass substrate 400 a (the thickness of the glass substrate 400 a is 120 μm) with sulfuric acid and hydrofluoric acid aqueous solutions, and then cleaning with pure water;

[0148] 3) The cleaned glass substrate 400a is placed horizontally in a glass etching solution at a temperature of 25°C, with an immersion depth of 120 mm;

[0149] 4) turning on the bubbling device for bubbling, and the bubbling etching time is 20 minutes; and

[0150] 5) After the set etching time is reached, the etched glass substrate 400a is taken out and cleaned with flowing pure water. After air drying, the desired glass cover plate 400 is obtained.

[0151] The glass cover plate 400 manufactured in this embodiment has a reduced thickness of 63 μm compared to the glass substrate 400 a .

[0152] Example 3

[0153] The glass cover plate 400 of this embodiment is prepared by the following steps:

[0154] 1) preparing a glass etching solution, which comprises, by mass fraction, 40% hydrofluoric acid, 18% sulfuric acid, 10% nitric acid, 6% oxalic acid, 2% ammonium bifluoride, 0.2% polyacrylamide, 0.3% borax and 23.5% water;

[0155] 2) Pre-treating the glass substrate 400 a (the thickness of the glass substrate 400 a is 120 μm) with sulfuric acid and hydrofluoric acid aqueous solutions, and then cleaning with pure water;

[0156] 3) The cleaned glass substrate 400a is placed horizontally in a glass etching solution at a temperature of 22°C, with an immersion depth of 130 mm;

[0157] 4) turning on the bubbling device for bubbling, and the bubbling etching time is 27.5 minutes; and

[0158] 5) After the set etching time is reached, the etched glass substrate 400a is taken out and cleaned with flowing pure water. After air drying, the desired glass cover plate 400 is obtained.

[0159] The glass cover plate 400 manufactured in this embodiment has a reduced thickness of 81 μm compared to the glass substrate 400 a .

[0160] Examples 1 to 3 use the same type of glass substrate 400a, and the transmittance, glossiness, reflectivity, roughness and haze of the glass cover plates 400 prepared in Examples 1 to 3 are tested. The test results are shown in Table 1 below.

[0161] Table 1 Performance parameters of the glass cover plate 400 of Examples 1 to 3

[0162]

[0163]

[0164] From the data obtained from the test in Table 1, it can be seen that the glass cover plate 400 obtained by etching and thinning the glass substrate 400a using the glass etching liquid of the embodiment of the present application has a high light transmittance, and the reduction of the light transmittance of the prepared glass cover plate 400 compared with the glass substrate 400a is less than 0.3%, which shows that after etching and thinning by the glass etching liquid of the present application, the influence on the original light transmittance of the glass substrate 400a is very small. In addition, the glass cover plate 400 after etching and thinning by the glass etching liquid of the present application has a lower reflectivity and higher glossiness than the glass substrate 400a. The roughness of the surface of the glass cover plate 400 and the haze of the glass cover plate 400 are both very small compared with the increase of the glass substrate 400a. This shows that after the glass etching liquid of the present application is used to thin the glass substrate 400a, the influence on the light transmittance, reflectivity, roughness and haze of the glass is very small, so that the prepared glass cover plate 400 can be better applied to the flexible display screen without affecting the display effect of the flexible display screen.

[0165] The glass substrate 400a and the glass cover plate 400 obtained in Examples 1 to 3 are scanned by electron microscope, and the electron microscope photographs of the glass substrate 400a are as follows: Figures 10 to 13 As shown. Among them, Fig.10 This is an electron microscope photograph (640 times) of the glass substrate 400a. Fig.11 This is an electron microscope photograph (640 times) of the glass cover plate 400 of Example 1. Fig.12 This is an electron microscope photograph (640 times) of the glass cover plate 400 of Example 2. Fig.13: is an electron microscope photograph (640 times) of the glass cover plate 400 of Example 3. From the electron microscope photographs of the glass substrate 400a and Examples 1 to 3, it can be seen that the surface of the glass cover plate 400 prepared by Examples 1 to 3 of the present application is not much different from the surface of the glass substrate 400a. The surface of the glass cover plate 400 prepared by Examples 1 to 3 does not have defects such as crystal points, flow lines and color differences, and has good surface smoothness and flatness.

[0166] See also Fig.14 The embodiment of the present application further provides a flexible display screen 500 , which includes: a display layer 510 and the glass cover plate 400 described in the embodiment of the present application, wherein the glass cover plate 400 and the display layer 510 are stacked to protect the display layer 510 .

[0167] Optionally, the display layer 510 may be, but is not limited to, an organic display layer 510 , such as an active matrix organic light emitting diode (AMOLED).

[0168] Optionally, the display layer 510 may be bonded to the glass cover plate 400 by using an adhesive with high light transmittance such as optical adhesive (OCA adhesive).

[0169] For a detailed description of the glass cover plate 400 , please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0170] It can be understood that the flexible display screen 500 in this embodiment is only one form of the flexible display screen 500 applied to the glass cover plate 400, and should not be understood as a limitation on the flexible display screen 500 provided in this application, nor should it be understood as a limitation on the glass cover plate 400 provided in each embodiment of this application. For a detailed description of the glass cover plate 400, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0171] See also Figures 15 to 17 The embodiment of the present application also provides a foldable electronic device 600, which includes: the flexible display screen 500 described in the embodiment of the present application, a foldable mechanism 610 and a processor 630, wherein the foldable mechanism 610 is used to carry the flexible display screen 500 and to drive the flexible display screen 500 to fold or flatten, wherein the glass cover plate 400 of the flexible display screen 500 is farther away from the foldable mechanism 610 than the display layer 510; the processor 630 is electrically connected to the flexible display screen 500, and is used to control the display screen to display.

[0172] The foldable electronic device 600 of the embodiment of the present application may be, but is not limited to, a portable foldable electronic device 600 with a variable display screen size such as a mobile phone, a tablet computer, an e-reader, and a laptop computer. It can be understood that the foldable electronic device 600 in this embodiment is only a form of the foldable electronic device 600 applied to the flexible display screen 500, and should not be understood as a limitation on the foldable electronic device 600 provided in the present application, nor should it be understood as a limitation on the flexible display screen 500 provided in each embodiment of the present application. For a detailed description of the flexible display screen 500, please refer to the description of the corresponding part of the above embodiment, which will not be repeated here.

[0173] For a detailed description of the flexible display screen 500 , the glass cover plate 400 , etc., please refer to the description of the corresponding parts of the above embodiments, which will not be repeated here.

[0174] Please also see Fig.18 In some embodiments, the foldable mechanism 610 includes a first carrier 611, a connecting shaft 613 and a second carrier 615 that are movably connected in sequence; the first carrier 611, the connecting shaft 613 and the second carrier 615 are used to support the flexible display screen 500 and drive the flexible display screen 500 to fold or unfold; the foldable mechanism 610 has a flattened state and a folded state. When the foldable mechanism 610 is in the flattened state, the first carrier 611, the connecting member and the second carrier 615 form a planar structure; when the foldable mechanism 610 is in the folded state, the first carrier 611 overlaps with the second carrier 615 and drives the flexible display screen 500 to fold.

[0175] It can be understood that when the orthographic projection of the surface of the foldable mechanism 610 of the flexible display screen 500 facing the flexible display screen 500 falls within the range of the surface of the foldable mechanism 610 facing the flexible display screen 500.

[0176] Optionally, the processor 630 includes one or more general-purpose processors, wherein the general-purpose processor can be any type of device capable of processing electronic instructions, including a central processing unit (CPU), a microprocessor, a microcontroller, a main processor, a controller, and an ASIC, etc. The processor 630 is used to execute various types of digital storage instructions, such as software or firmware programs stored in a memory, which enables the computing device to provide a wide variety of services.

[0177] Optionally, the foldable electronic device 600 of the present application further includes a memory 650. The memory 650 is electrically connected to the processor 630 and is used to store program codes required for the processor 630 to run, program codes required for controlling the flexible display screen 500, display content of the flexible display screen 500, and the like.

[0178] Optionally, the memory 650 may include a volatile memory (Volatile Memory), such as a random access memory (Random Access Memory, RAM); the memory 650 may also include a non-volatile memory (NVM), such as a read-only memory (Read-Only Memory, ROM), a flash memory (Flash Memory, FM), a hard disk drive (Hard Disk Drive, HDD) or a solid-state drive (SSD). The memory 650 may also include a combination of the above-mentioned types of memory.

[0179] In some embodiments, the foldable electronic device 600 of the embodiment of the present application further includes a camera module 670, and the camera module 670 is carried by the foldable middle frame 610. The camera module 670 is electrically connected to the processor 630, and is used to shoot under the control of the processor 630.

[0180] Optionally, the camera module 670 may be a rear camera module 670 or a front camera module 670. This application does not make any specific limitation.

[0181] Mentioning "embodiment" and "implementation method" in this application means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrases in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments. In addition, it should also be understood that the features, structures or characteristics described in the various embodiments of the present application can be arbitrarily combined to form another embodiment that does not deviate from the spirit and scope of the technical solution of the present application, provided that there is no contradiction between them.

[0182] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the above preferred implementation modes, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A glass etching solution, characterized in that: The glass etching solution comprises, by mass fraction: 30% to 50% hydrofluoric acid; 10% to 30% sulfuric acid; 5% to 20% nitric acid; and 2% to 8% oxalic acid.

2. The glass etching solution according to claim 1, characterized in that: The glass etching solution also includes borax, and the mass fraction of the borax ranges from 0.2% to 0.5%.

3. The glass etching solution according to claim 1, characterized in that: The glass etching solution also includes ammonium bifluoride, and the mass fraction of the ammonium bifluoride ranges from 1% to 3%.

4. The glass etching solution according to any one of claims 1 to 3, characterized in that: The glass etching solution also includes polyacrylamide, and the mass fraction of the polyacrylamide ranges from 0.2% to 0.5%.

5. A method for preparing a glass cover plate, characterized in that: include: providing a glass substrate; as well as The glass substrate is immersed in a glass etching solution for etching to obtain a glass cover plate, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid and 2% to 8% oxalic acid.

6. The method for preparing a glass cover plate according to claim 5, characterized in that: The step of immersing the glass substrate in a glass etching solution for etching comprises: The glass substrate is immersed in a glass etching solution with a temperature T in the range of 15° C. ≤ T ≤ 25° C. for etching.

7. The method for preparing a glass cover plate according to claim 5 or 6, characterized in that: The step of immersing the glass substrate in a glass etching solution for etching comprises: immersing the glass substrate in a glass etching solution; and The glass etching solution is bubbled.

8. The method for preparing a glass cover plate according to claim 7, characterized in that: The bubbling of the etching solution comprises: A plurality of bubbling tubes arranged at intervals are arranged in the etching liquid, and air flow is passed into the bubbling tubes for bubbling; wherein each of the bubbling tubes has a plurality of bubbling holes arranged at intervals, and the range of the aperture d of the bubbling holes is: 0.3mm≤d≤0.6mm; the range of the spacing s between two adjacent bubbling holes on the same bubbling tube is: 60mm≤s≤80mm.

9. The method for preparing a glass cover plate according to claim 8, characterized in that: The diameter D of each bubbling tube is in the range of 20 mm ≤ D ≤ 40 mm; the air pressure P of the airflow in each bubbling tube is in the range of 0.3 MPa to 0.8 MPa.

10. A glass cover plate, characterized in that: The glass cover plate is obtained by etching a glass substrate with a glass etching solution, wherein the glass etching solution comprises, by mass fraction, 30% to 50% hydrofluoric acid, 10% to 30% sulfuric acid, 5% to 20% nitric acid and 2% to 8% oxalic acid.

11. A glass cover plate, characterized in that: The thickness h of the glass cover plate is in the range of 10 μm≤h≤60 μm; the surface roughness Ra of the glass cover plate is in the range of 0.02 μm≤Ra≤0.06 μm.

12. The glass cover plate according to claim 11, characterized in that: The light transmittance of the glass cover plate is 90% to 99%, the reflectivity of the glass cover plate is 0.5% to 9.5%; and the haze of the glass cover plate is 0.03% to 0.06%.

13. The glass cover plate according to any one of claims 10 to 12, characterized in that: The glass cover plate is prepared by the method according to any one of claims 5 to 9.

14. A flexible display screen, characterized in that: include: Display layer; as well as The glass cover plate according to any one of claims 10 to 13, wherein the glass cover plate is stacked with the display layer to protect the display layer.

15. A foldable electronic device, characterized in that: include: The flexible display screen according to claim 14; A foldable mechanism, the foldable mechanism is used to carry the flexible display screen and drive the flexible display screen to be folded or flattened, wherein the glass cover plate of the flexible display screen is farther away from the foldable mechanism than the display layer; as well as A processor is electrically connected to the flexible display screen and is used to control the display screen to display.

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