Unequal-thickness ultra-thin glass as well as method and application thereof

Abstract

The invention provides unequal-thickness ultra-thin glass and a preparation method and application thereof.The unequal-thickness ultra-thin glass adopts a specific formula calculated according to the percentage of oxides, the ratio of (Al2O3 + Na2O + K2O + MgO) / (B2O3 + SiO2) is controlled to range from 52% to 68% on the basis that ZnO, P2O5 and SrO are not added by controlling the components adopted in the formula and the matching relation among the components, and the unequal-thickness ultra-thin glass is obtained. The maximum thickness of the unequal-thickness ultra-thin glass is controlled, so that the light transmittance of the unequal-thickness ultra-thin glass can reach 91%, the fracture toughness of the unequal-thickness ultra-thin glass can be larger than or equal to 0.76 MPa.m < 1 / 2 >, the Vickers hardness of the unequal-thickness ultra-thin glass can reach 573 kgf / mm < 2 > or above, the average single drop pen impact height of a non-bending area of the unequal-thickness ultra-thin glass can reach 100 mm or above, and the unequal-thickness ultra-thin glass has good bending performance, impact resistance and drop resistance.

Description

Technical Field

[0001] The present application relates to the technical field of glass materials, and in particular to ultra-thin glass of unequal thickness, a method for producing the same, and uses thereof. Background Art

[0002] In recent years, foldable electronic products have seen rapid updates and iterations, with the front cover materials of these products gradually transitioning from polymers to ultra-thin glass. Ultra-thin glass, with its excellent optical and mechanical properties, is widely used in display materials such as foldable electronic products. However, ultra-thin glass itself lacks toughness and strength, making it prone to breakage during use due to drops, impacts with hard objects, and other factors. Furthermore, the insufficient thickness of ultra-thin glass often leads to insufficient support for the screen module, resulting in a poor user experience.

[0003] In order to improve the performance balance of ultra-thin glass, research on unequal thickness ultra-thin glass has been carried out, which is also regarded as an alternative to the next generation of foldable screen electronic cover materials. Unequal thickness ultra-thin glass contains bending areas and non-bending areas. The bending areas maintain good bending performance by reducing the thickness, while the non-bending areas ensure impact resistance and strength by increasing the thickness. It can achieve both good bending performance and excellent impact resistance and drop resistance. However, unequal thickness ultra-thin glass has higher requirements for process technology. Although there is currently a market demand for unequal thickness ultra-thin glass that guarantees good bending performance while also taking into account excellent impact resistance and drop resistance, few unequal thickness ultra-thin glasses that can meet this demand have been produced. Summary of the Invention

[0004] The purpose of this application is to provide an ultra-thin glass of unequal thickness and its preparation method and use, wherein the fracture toughness of the ultra-thin glass of unequal thickness can reach ≥0.76MPa·m 1 / 2 , Vickers hardness can reach 573kgf / mm 2 The average single pen impact height in the non-bending area can reach more than 100 mm, and it has good bending performance and impact resistance and drop resistance.

[0005] In a first aspect, the present application provides an ultra-thin glass of unequal thickness, comprising a bending zone, a non-bending zone, and a buffer zone, wherein the buffer zones are symmetrically distributed on both sides of the bending zone, and the non-bending zones are respectively located on the side of the two buffer zones away from the bending zone; the thickness L2 of the non-bending zone is 0.035-0.35 mm;

[0006] Calculated in percentage by mass of oxides, it includes the following components:

[0007] SiO2: 55.0-65.0%;

[0008] Al2O3: 15.0-20.0%;

[0009] Li2O: 0-2.5%;

[0010] Na2O: 10-18.0%;

[0011] K2O: 1-6%;

[0012] MgO: 3-5.5%;

[0013] CaO: 0-1%;

[0014] Y2O3: 0-1%;

[0015] ZrO2: 0.1-2.0%;

[0016] B2O3: 0.1-3.0%;

[0017] Among them, each component satisfies the following relationship:

[0018] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%;

[0019] Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

[0020] Furthermore, in some embodiments of the present application, the fracture toughness of the ultra-thin glass of unequal thickness is ≥0.76 MPa·m 1 / 2 .

[0021] Furthermore, in some embodiments of the present application, the Vickers hardness of the ultra-thin glass of unequal thickness is ≥573 kgf / mm 2 .

[0022] Furthermore, in some embodiments of the present application, when the thickness L2 of the non-bending zone of the ultra-thin glass of unequal thickness is 0.035 mm, the average pen impact height of the ultra-thin glass of unequal thickness is not less than 100 mm.

[0023] Furthermore, in some embodiments of the present application, when the thickness L2 of the non-bending zone of the ultra-thin glass of unequal thickness is 0.035 mm, the average coating pen impact height of the ultra-thin glass of unequal thickness is not less than 170 mm.

[0024] Furthermore, in some embodiments of the present application, the maximum thickness Hmax of the unequal thickness ultra-thin glass is 0.07-0.35 mm; wherein the ratio W of the thickness of the non-bending zone to the maximum thickness Hmax is: W=L2 / Hmax is 0.5 or 1.0;

[0025] When W is 0.5, bending areas, non-bending areas and buffer zones are provided on both sides of the overall thickness direction of the unequal thickness ultra-thin glass.

[0026] Furthermore, in some embodiments of the present application, the width and depth of the buffer zone and the thickness of the bending zone of the ultra-thin glass of unequal thickness satisfy the following formula: B=10×d / W+0.01×A×W, and B is 0.301-0.929;

[0027] Among them, A is the depth-to-width ratio of the buffer zone of the ultra-thin glass product of unequal thickness, and its calculation formula is: ratio A=100×(c / a); among them, a is the width of the buffer zone; c is the depth of the buffer zone; d is the thickness of the bending zone.

[0028] Furthermore, in some embodiments of the present application, the value range of A is 0.022-2.286.

[0029] Furthermore, in some embodiments of the present application, the maximum bending radius R(2PB) of the ultra-thin glass of unequal thickness is 0.2-2.05 mm.

[0030] Furthermore, in some embodiments of the present application, when the thickness of the bending zone is 0.07 mm, the maximum bending radius R(2PB) of the ultra-thin glass of unequal thickness is 1.75-2.05 mm.

[0031] Furthermore, in some embodiments of the present application, when the thickness of the bending zone is 0.03 mm, the limit bending radius R(2PB) of the ultra-thin glass of unequal thickness is 0.20-0.55 mm.

[0032] Furthermore, in some embodiments of the present application, the thickness and width of the buffer zone and the bending zone of the ultra-thin glass of unequal thickness satisfy the following formula:

[0033] C = b + 0.1 / A, where C is 7.044-29.500.

[0034] Among them, A is the depth-to-width ratio of the buffer zone of the ultra-thin glass product of unequal thickness, and its calculation formula is: ratio A=100*(c / a); among them, a is the width of the buffer zone; c is the depth of the buffer zone; b is the width of the bending zone.

[0035] Furthermore, in some embodiments of the present application, the offset bending distance of ultra-thin glasses of unequal thickness is 3-13 mm.

[0036] Furthermore, in some embodiments of the present application, when the thickness of the bending zone is 0.07 mm, the shiftable bending distance of the ultra-thin glass of unequal thickness is 3.20 to 12.50 mm.

[0037] Furthermore, in some embodiments of the present application, when the thickness of the bending zone is 0.03 mm, the shiftable bending distance of the ultra-thin glass of unequal thickness is 3.05 to 12.95 mm.

[0038] Furthermore, in some embodiments of the present application, the bending life of ultra-thin glass of unequal thickness is: R0.8-R2.5>200,000 times.

[0039] Furthermore, in some embodiments of the present application, the ultra-thin glass of unequal thickness does not contain SnO2.

[0040] Furthermore, in some embodiments of the present application, when the ultra-thin glass of unequal thickness is 0.03-0.35 mm in thickness, the light transmittance at 550 nm is ≥91.0%.

[0041] Furthermore, in some embodiments of the present application, the width a of the buffer zone is 14-45 mm, and the width b of the bending zone is 7-25 mm;

[0042] The depth c of the buffer zone is 0.02-0.32 mm, and the thickness d of the bending zone is 0.015-0.1 mm.

[0043] Furthermore, in some embodiments of the present application, the CS of the ultra-thin glass of unequal thickness is not less than 500 MPa.

[0044] In a second aspect, the present application further provides a method for preparing the ultra-thin glass of unequal thickness as described in the first aspect, comprising the following steps:

[0045] Step 1: Providing ultra-thin base glass;

[0046] Step 2: chemically etching the ultra-thin base glass provided in step 1 to obtain ultra-thin glasses of varying thicknesses;

[0047] Step 3: Chemically strengthen the ultra-thin glass of unequal thickness provided in step 2 to obtain strengthened ultra-thin glass of unequal thickness.

[0048] Further, in some embodiments of the present application, the chemical etching includes chemically etching the fixed area of ​​the ultra-thin base glass using a first etching solution, and the chemical etching method is selected from top-spray chemical etching or immersion chemical etching;

[0049] Furthermore, the method of chemically etching the fixed area of ​​the ultra-thin base glass is selected from any one of a mask method, a mold method or a directional guide method;

[0050] Furthermore, the masking method is selected from a yellow light masking method and a coating method;

[0051] Furthermore, the mold method is selected from the arc mold fixed etching method;

[0052] Furthermore, the directional flow guiding method is selected from the precision liquid flow guiding etching method and the forward and reverse pulling method;

[0053] and / or

[0054] The first etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride; and / or

[0055] The etching temperature in chemical etching is 20°C to 50°C, and / or

[0056] The etching rate in chemical etching is 0.1 μm / min to 20 μm / min.

[0057] Further, in some embodiments of the present application, the chemical strengthening includes a first chemical strengthening process and a second chemical strengthening process;

[0058] The first chemical strengthening process includes one or more chemical strengthening treatments, the temperature of the molten salt bath used in the chemical strengthening treatment is 380° C. to 550° C., the chemical strengthening time is 5 min to 240 min, and the molten salt used in the molten salt bath includes 0-50 wt% sodium salt, 40-100 wt% potassium salt, and 0-10 wt% lithium salt; further, the lithium salt is one or more of lithium nitrate and lithium sulfate; further, the sodium salt is one or more of sodium nitrate, sodium sulfate, and sodium carbonate; further, the potassium salt is one or more of potassium nitrate, potassium sulfate, and potassium carbonate; and / or

[0059] The second chemical strengthening process includes placing the ultra-thin glass product of unequal thickness after the first chemical strengthening process in a third etching solution for 60s to 1200s to obtain ultra-thin glass of unequal thickness; wherein the third etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride.

[0060] Furthermore, in some embodiments of the present application, an edge processing process is further included between the chemical etching process and the chemical strengthening process;

[0061] The edge processing step includes using a second etching solution to perform edge processing on the glass products of varying thickness that have undergone the chemical etching step;

[0062] The second etching solution is selected from one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride;

[0063] Furthermore, the glass product of unequal thickness after the chemical etching process includes a first surface and a second surface formed in the width and length directions, and the first surface and the second surface are coated with a strong acid-resistant ink before the edge processing process is performed;

[0064] Furthermore, after the edge treatment process and before the chemical strengthening process, a strong acid-resistant ink removal process is also included; the strong acid-resistant ink removal process includes using an alkaline solution to remove the strong acid-resistant ink from the glass products of varying thickness that have undergone the edge treatment process; further, the alkaline solution is selected from NaOH, NaHCO3, Na2CO3, C6H 11 NaO7、C6H 15 One or more of NO3;

[0065] Furthermore, in the edge processing step, the etching temperature of the second etching solution for treating the glass products of unequal thickness is 20° C. to 50° C., the etching rate is 0.1 μm / min to 10 μm / min, and the etching time is 1 min to 10 min.

[0066] In a third aspect, the present application further provides an ultra-thin base glass for preparing the ultra-thin glass of unequal thickness described in the first aspect, wherein the ultra-thin base glass has a thickness of 0.03-0.4 mm and comprises the following components, calculated in terms of the mass percentage of oxides:

[0067] SiO2: 55.0-65.0%;

[0068] Al2O3: 15.0-20.0%;

[0069] Li2O: 0-2.5%;

[0070] Na2O: 10-18.0%;

[0071] K2O: 1-6%;

[0072] MgO: 3-5.5%;

[0073] CaO: 0-1%;

[0074] Y2O3: 0-1%;

[0075] ZrO2: 0.1-2.0%;

[0076] B2O3: 0.1-3.0%;

[0077] Among them, each component satisfies the following relationship:

[0078] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%;

[0079] Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

[0080] Furthermore, in some embodiments of the present application, the ultra-thin base glass does not contain SnO2.

[0081] Furthermore, in some embodiments of the present application, the ultra-thin base glass has a total thickness deviation TTV of ≤5 μm when the length and width are 200 mm*200 mm.

[0082] Furthermore, in some embodiments of the present application, the ultra-thin base glass is obtained by one-time molding using raw materials through a down-draw method; further, the melting temperature of the raw materials is 1350°C-1700°C, the melting time is 4h-240h, the annealing temperature is 550°C-650°C, and the annealing time is 0.5min-2000min.

[0083] In a fourth aspect, the present application also provides the use of the unequal thickness ultra-thin glass as described in the first aspect or the unequal thickness ultra-thin glass prepared by the preparation method of the unequal thickness ultra-thin glass as described in the second aspect in automobile displays or windows, foldable electronic devices, aerospace window glass, aviation radiation-resistant glass, advertising display screens, building curtain walls, and furniture decoration.

[0084] In a fourth aspect, the present application also provides a foldable electronic device, comprising the ultra-thin glass of unequal thickness as described in the first aspect or the ultra-thin glass of unequal thickness prepared by the method for preparing the ultra-thin glass of unequal thickness as described in the second aspect.

[0085] Beneficial effects of this application:

[0086] 1. The unequal thickness ultra-thin glass provided in this application adopts a specific formula calculated based on the percentage of oxides, and by controlling the components used in the formula and the ratio between the components, the ratio of (Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2) is controlled to fall within the range of 52% to 68% without adding ZnO, P2O5 and SrO, and the maximum thickness of the unequal thickness ultra-thin glass is controlled, so that the obtained unequal thickness ultra-thin glass has excellent high fracture toughness, high drop resistance and high impact resistance.

[0087] 2. The unequal thickness ultra-thin glass provided in the present application can also make its aspect ratio A, B = 10*d / W + 0.01*A*w, C = b + 0.1 / A meet a certain range through the depth and width of its buffer zone and bending zone, so that the bending performance of the unequal thickness ultra-thin glass products can reach a maximum bending radius R (2PB) of 0.2 to 2.05 mm. At the same time, the adjustable bending distance can reach 3-13 mm; the bending life is: R0.8-R2.5 can be greater than 200,000 times.

[0088] 3. The ultra-thin glass of unequal thickness provided in this application not only has good high fracture toughness, drop resistance and impact resistance, but also has good impact resistance in the non-bending area and good bending performance in the bending area, achieving the combination of impact resistance, bending resistance and drop resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0090] Figure 1 This is a schematic diagram of the structure of ultra-thin glass of unequal thickness when the value of W provided in this application is 1;

[0091] Figure 2 Schematic diagram of the structure of ultra-thin glass of unequal thickness when the value of W provided in this application is 0.5;

[0092] Figure 3 A schematic diagram of the test of the ultra-thin glass of unequal thickness provided in this application during the average single-unit pen drop impact height test;

[0093] Figure 4 A schematic diagram of the test of the average coating pen impact height test on the ultra-thin glass of unequal thickness provided in this application;

[0094] Figure 5 Schematic diagram of the test of the average limit bending radius of the ultra-thin glass of unequal thickness provided in this application

[0095] Figure 6 This is a test diagram of the unequal thickness ultra-thin glass provided in this application during the offset bending movement distance test.

[0096] Among them, 1-ultra-thin glass of unequal thickness, 2-first surface, 3-second surface, 11-stainless steel plate, 12-marker pen, 22-first baffle, 23-second baffle. DETAILED DESCRIPTION

[0097] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions 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 invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0098] In this application, transmittance refers to the ratio of the radiant energy projected and transmitted through an object to the total radiant energy projected onto the object during the process of the incident light flux leaving from the illuminated surface or the incident surface of the medium to the other surface.

[0099] In this application, base glass refers to glass that has not been etched or strengthened.

[0100] Test method:

[0101] 1. Stress test:

[0102] In this application, the CS, CT, and DOL of the glass to be tested were tested using an FSM-6000 device. During the test, the refractive index was set to 1.504 and the photoelastic coefficient was set to 28.6. The average strengthening rate was calculated using the DOL value measured per unit time interval.

[0103] 2. Optical performance test

[0104] Transmittance testing was performed using a haze meter in accordance with the national standard "GB / T 7962.12-2010, Test Methods for Colorless Optical Glass - Part 12: Spectral Transmittance." Specifically, the haze meter was used to test the transmittance of five glasses from the same batch at different wavelengths. The average transmittance of these five glasses at 550nm was taken as the transmittance result for the glass at 550nm.

[0105] The haze meter used in the test of this application is a Konica Minolta spectrophotometer CM-3600A from Japan. The light receiving optical system is transmission, the spectroscopic method is a plane reflective grating, the wavelength range is 360nm to 740nm, the wavelength interval is 10nm, the illumination light source is a pulsed xenon lamp X4, and the ambient temperature of the instrument is 24°C and the air humidity is 40%.

[0106] 3. Vickers hardness test

[0107] Flexible glass was made into small pieces with a length, width and thickness of 50 mm × 50 mm × 0.7 mm. Glass samples with a clean surface and no visible scratches, pits, cracks or other damage were selected as test samples, and then their Vickers hardness was measured using a Vickers hardness tester. The Vickers hardness tester used in the test of the present invention is a digital display low-load Vickers hardness tester model VTD405 produced by Beijing Kewei Technology Co., Ltd. The test conditions are: load 300 gf, load time 10 s, and the validity of the indentation complies with the standard "GB / T37900-2019 Ultra-thin glass hardness and fracture toughness test method small load Vickers hardness indentation method".

[0108] Select three different locations on the surface of the same test sample for measurement, and take the average of the three measurement results as the Vickers hardness result of the test sample.

[0109] 4. Thickness test

[0110] In this application, a digital micrometer (mitutoyo 406-250-30) or a laser thickness gauge is used to measure the thickness of the glass to be tested. The average etching rate is obtained by the thickness value per unit etching time interval.

[0111] 5. Fracture toughness test

[0112] Tests are conducted according to the standard "GB / T 37900-2019 Ultra-thin glass hardness and fracture toughness test method - Small-load Vickers hardness indentation method." Specifically, an indentation is prepared using the same method as for Vickers hardness measurement. The crack lengths 2C1 and 2C2 along the diagonal direction of the indentation are measured, with the maximum value not exceeding the thickness of the glass. At least five effective indentation measurements are performed on each specimen surface, and the average value is calculated as the final result for that specimen.

[0113] 6. Average single pen drop impact height test

[0114] In this application, the glass to be tested is placed on a stainless steel plate 11 and the pen impact is tested using a standard 12.6g marker 12. The average of the pen impact heights measured on 5 pieces of glass to be tested is taken as the average pen impact height H of the glass to be tested. d , see Figure 3 .

[0115] 7. Average lamination pen impact height test

[0116] In this application, a standard 12.6g marker 12 is used to test the pen impact. Before testing the pen impact height, a 50μm OCA optical adhesive + 50μm PET film is applied to the first surface 2 and the second surface 3 of the glass to be tested using a roller press. The average pen impact height measured on 5 pieces of coated glass to be tested is taken as the average coated pen impact height H of the glass to be tested. f, see Figure 4 .

[0117] 8. Limit bending radius test

[0118] In this application, the test was carried out using the national standard GB / T 38686-2020 "Two-point bending method for ultra-thin glass flexibility test method". Specifically, high-temperature adhesive tape is used to fix the UTG / UFG in the parallel first baffle 22 and the second baffle 23. The first surface of the glass to be tested is used as the compression force surface, and the second surface is used as the tension force surface. The single parallel baffle is moved at a speed of 0.5mm / s to slowly reduce the distance between the plates until the glass breaks. The limit bending radius R is calculated as R=0.5*(Dd / W). The average limit bending radius of 5 pieces of glass to be tested is measured. Figure 5 .

[0119] 9. Displacement bending distance test

[0120] In this application, high-temperature adhesive tape is used to fix ultra-thin glass of unequal thickness between two parallel baffles. The first surface of the glass to be tested is used as the compression force surface, and the second surface is used as the tension force surface. The parallel first baffle 22 and the second baffle 23 are moved between the fixed plates. The baffle on one side is fixed, and the Z axis moves up or down the other baffle at 0.2mm / s until the glass to be tested breaks. The average displacement distance Hc of the test baffle is measured by taking 5 pieces of glass to be tested. Figure 6 .

[0121] 10. Bending life test

[0122] In this application, high-temperature adhesive tape is used to fix ultra-thin glass of unequal thickness on the two baffles of the dynamic bending fixture. The first surface of the glass to be tested is used as the compression stress surface, and the second surface is used as the tension stress surface. The temperature and humidity are guaranteed to be: 10~30℃, 35%~75% RH. The fixed plates are then bent from 180° to 0° at a bending speed of 30cycle / min. The number of bending times is set to 200,000 times, and no breakage is considered passed / OK.

[0123] 11. Test method for mass percentage of Li2O and B2O3 components

[0124] In this application, the mass percentages of Li2O and B2O3 components in the glass are tested according to the national standard GB\T 1549-2008.

[0125] 12. Determination of Mass Percentage of Glass Composition in the Application

[0126] The composition of the glass in this application was measured by X-ray fluorescence spectrometer (XRF). The equipment used for the test was ThermoScientific ARL TMPERFORM'X, target material: Rh (rhodium), tube voltage: 40kW, current: 60mA, collimator: 0.15, crystal: LiF200, detector: FPC, test range: 29mm circle, analysis software: UniQuant standardless analysis. XRF testing uses standardless analysis, so the equipment cannot measure the concentration of elements with atomic numbers 6 and below or their oxides in glass. XRF can accurately measure the mass percentages of oxides such as SiO2, Al2O3, P2O5, ZrO2, Na2O, K2O, CaO, NiO, Y2O3, SrO, MgO, and ZnO. Li2O and B2O3 are oxides that XRF cannot accurately measure.

[0127] Therefore, by substituting the Li2O and B2O3 content values ​​obtained from the above test into the XRF test results, the mass percentages of the complete glass components can be obtained.

[0128] Unequal thickness flexible glass is one of the key components for forming a foldable screen. Compared with traditional equal thickness glass, it has a thinning design in the middle part, which effectively reduces the local stress concentration problem that may be generated by the flexible screen during the folding process, and provides material support for the wide range of long-term applications of foldable screens. However, since the folding screen also puts forward ultra-thin requirements for the unequal thickness flexible glass, under the ultra-thin thickness requirements, its impact resistance, drop resistance, and fracture toughness are significantly reduced, and the bending performance of the bending zone after thinning is also difficult to take into account. Based on this, the present application proposes an unequal thickness ultra-thin flexible glass suitable for folding screens. The unequal thickness ultra-thin flexible glass adopts a specific component formula and controls the formula relationship between the components. Within the maximum thickness Hmax range of 0.07-0.35mm, the obtained unequal thickness ultra-thin flexible glass can have both bending resistance, drop resistance, impact resistance and high fracture toughness, so that it can meet the ultra-thin thickness requirements of existing folding screens and meet the performance requirements of folding screens.

[0129] In a first aspect, the present application provides an ultra-thin glass of unequal thickness, the ultra-thin glass of unequal thickness comprising a bending area, a non-bending area, and a buffer area, wherein the buffer areas are symmetrically distributed on both sides of the bending area, and the non-bending areas are respectively located on the side of the two buffer areas away from the bending area; the thickness L2 of the non-bending area is 0.035-0.35 mm;

[0130] Calculated in percentage by mass of oxides, it includes the following components:

[0131] SiO2: 55.0-65.0%;

[0132] Al2O3: 15.0-20.0%;

[0133] Li2O: 0-2.5%;

[0134] Na2O: 10-18.0%;

[0135] K2O: 1-6%;

[0136] MgO: 3-5.5%;

[0137] CaO: 0-1%;

[0138] Y2O3: 0-1%;

[0139] ZrO2: 0.1-2.0%;

[0140] B2O3: 0.1-3.0%;

[0141] Among them, each component satisfies the following relationship:

[0142] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%;

[0143] Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

[0144] In the present application, “the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO” should be understood as that when providing the raw materials for preparing the ultra-thin glass of unequal thickness of the present application, salts or elements containing ZnO, P2O5 and SrO or capable of forming oxides of ZnO, P2O5 and SrO are not actively added, and the content of impurities such as ZnO, P2O5 and SrO in other raw materials used is also controlled so that the total content of ZnO, P2O5 and SrO in the obtained ultra-thin glass of unequal thickness is not higher than 0.2%.

[0145] The applicant has found that when a certain amount of ZnO, P2O5 and SrO are present in ultra-thin glass of unequal thickness, it will affect the performance of the ultra-thin glass of unequal thickness formed after etching and strengthening, especially the fracture toughness and bending performance of the ultra-thin glass of unequal thickness. The reason may be that the buffer area and bending area of ​​the ultra-thin glass of unequal thickness usually need to be chemically etched and thinned by an etchant containing fluorine, and ZnO, as a typical network intermediate often used in glass, easily forms a zinc fluorosilicate product with strong adhesion during the etching process of the etchant containing fluorine, which hinders the chemical etching on the etched glass surface, thereby causing surface defects such as concave and convex points to form on the etched surface, affecting the performance of the bending area and buffer zone; in addition, the addition of ZnO, especially a large amount of ZnO, may also increase the CTE and have a problem of strengthening warping, and ZnO lowering the strain point may have a negative effect on chemically tempered glass, low-temperature relaxation will weaken the stability of the surface compressive stress layer, and a small amount of zinc oxide will cause a steeper stress distribution, reducing the stability of the bending performance. PO is a typical network former. Although it can independently construct a glass network based on [PO] tetrahedron, the increase in PO content leads to a loose network and reduces structural stability. In the glass network system provided in the present application, if a phosphate glass network is formed, the POP bonds therein are easily hydrolyzed, resulting in a significant deterioration of water resistance (especially in an environment with pH>7). The surface of ultra-thin glass is prone to dissolution, forming microcracks and accelerating strength decay; in addition, PO is prone to cause metastable phase separation, and the risk of crystallization is high, which is not conducive to production. In addition, SrO has a larger ionic radius than MgO and CaO, so that the ultra-thin glass of unequal thickness formed has a larger thermal expansion coefficient, which reduces its thermal shock resistance and makes it prone to warping and wrinkling defects during high-temperature strengthening.

[0146] In order to further improve the performance of the unequal thickness ultra-thin glass provided in this application, the unequal thickness ultra-thin glass provided in this application does not contain SnO2.

[0147] Similarly, in the present application, "the ultra-thin glass of unequal thickness does not contain SnO2" should be understood as meaning that when providing the raw materials for preparing the ultra-thin glass of unequal thickness of the present application, no salt or element containing SnO2 or capable of forming the oxide of SnO2 is actively added, and the content of impurities such as SnO2 in other raw materials used is also controlled so that the content of SnO2 in the ultra-thin glass of unequal thickness is not higher than 0.5%. It should be noted that the raw materials here refer to the main components of the formula for forming the ultra-thin glass of unequal thickness, and not other additives and auxiliary agents added to the ultra-thin glass of unequal thickness for processing purposes during the production process, such as clarifiers and molten salts used for etching and strengthening. Therefore, the statement "the ultra-thin glass of unequal thickness does not contain SnO2" in the present application should be understood as meaning that SnO2 and salts or elemental substances capable of forming the oxide of SnO2 are not actively added to the main formula components for forming the ultra-thin glass of unequal thickness.

[0148] The applicant found that when a certain amount of SnO2 exists in ultra-thin glass of unequal thickness, it is not conducive to its coloring performance and light transmittance. The reason may be that during the ion strengthening process, the SnO2 on the lower surface of the ultra-thin glass 4+ It is easy to cause differences in expansion increments, thereby causing bending deformation, and may produce light interference rainbow fringes, and react with the rhodium in the container during the production process, reducing the coloring properties and visible light transmittance of the formed ultra-thin glass of unequal thickness.

[0149] It should be noted that, during the preparation process of ultra-thin glass of unequal thickness, tin oxide can be appropriately added as a clarifier, resulting in the ultra-thin glass of unequal thickness containing a small amount of SnO2. This situation is not considered to be inconsistent with the statement in this application that "the ultra-thin glass of unequal thickness does not contain SnO2".

[0150] In the present application, SiO2 is an oxide that forms the glass network skeleton and is used to stabilize the network structure of the base glass. Excessive SiO2 content can cause the glass's solubility to deteriorate or increase the viscosity of the molten glass, making it difficult to clarify and forming the glass. In some embodiments of the present application, the SiO2 content in the ultra-thin glass of varying thickness, measured as a percentage by mass of the oxide, is between 55.00 wt% and 66.00 wt%, preferably between 58 wt% and 62 wt%, and more preferably between 59 wt% and 61 wt%. For example, in terms of the mass percentage of oxide, the content of SiO2 in the ultra-thin glass of unequal thickness can be: 55.00wt%, 55.50wt%, 56.00wt%, 56.50wt%, 57.00wt%, 57.50wt%, 58.00wt%, 58.50wt%, 59.00wt%, 59.50wt%, 60.00wt%, 60.50wt%, 61.00wt%, 61.50wt%, 62.00wt%, 62.50wt%, 63.00wt%, 63.50wt%, 64.00wt%, 64.50wt%, 65.00wt%, 65.50wt% or 76.00wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0151] In this application, Al2O3 can be used to construct the glass skeleton and supplement the network. The ion exchange rate can also be adjusted by changing the size of the space within the glass network for ion exchange. However, if the Al2O3 content is too high, the melting and operating temperatures of the glass will be very high, easily forming crystals, resulting in poor transparency and flexibility. In some embodiments of this application, the Al2O3 content in the ultra-thin glass of varying thickness is 15.00 wt% to 20.00 wt%, preferably 16.5 wt% to 18 wt%, and more preferably 17 wt% to 18 wt%, based on the mass percentage of the oxide. Exemplarily, the content of Al2O3 in the ultra-thin glass of unequal thickness may be, in terms of mass percentage of oxide, 15.00wt%, 15.20wt%, 15.40wt%, 15.60wt%, 15.80wt%, 16.00wt%, 16.20wt%, 16.40wt%, 16.60wt%, 16.80wt%, 17.00wt%, 17.20wt%, 17.40wt%, 17.60wt%, 17.80wt%, 18.00wt%, 18.20wt%, 18.40wt%, 18.60wt%, 18.80wt%, 19.00wt%, 19.20wt%, 19.40wt%, 19.60wt%, 19.80wt% or 20.00wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0152] In this application, CaO is an oxide outside the glass network that can lower the glass forming temperature and improve the glass's Young's modulus and strength. In some embodiments of this application, the CaO content in the ultra-thin glass of varying thickness is 0.00 wt% to 1.00 wt%, preferably 0 wt% to 0.8 wt%, and more preferably 0.1 wt% to 0.5 wt%, calculated as a percentage by mass of the oxide. For example, in terms of the mass percentage of oxide, the CaO content in the ultra-thin glass of unequal thickness can be: 0.00 wt%, 0.05 wt%, 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, 0.35 wt%, 0.40 wt%, 0.45 wt%, 0.50 wt%, 0.55 wt%, 0.60 wt%, 0.65 wt%, 0.70 wt%, 0.75 wt%, 0.80 wt%, 0.85 wt%, 0.90 wt%, 0.95 wt% or 1.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0153] In the present application, ZrO2 acts as a network intermediate. An appropriate amount of ZrO2 can increase the viscosity, Young's modulus, refractive index, chemical stability of the glass and reduce the thermal expansion coefficient of the glass. However, excessive ZrO2 can increase the difficulty of melting the substrate glass and cause crystallization. In some embodiments of the present application, the ZrO2 content in the ultra-thin glass of varying thickness is 0.10wt% to 2.00wt%, preferably 0.5wt% to 1.5wt%, and more preferably 0.5wt% to 1.0wt%, calculated as a percentage by mass of the oxide. For example, in terms of the mass percentage of oxide, the content of ZrO2 in the ultra-thin glass of unequal thickness can be 0.10wt%, 0.20wt%, 0.30wt%, 0.40wt%, 0.50wt%, 0.60wt%, 0.70wt%, 0.80wt%, 0.90wt%, 1.00wt%, 1.10wt%, 1.20wt%, 1.30wt%, 1.40wt%, 1.50wt%, 1.60wt%, 1.70wt%, 1.80wt%, 1.90wt% or 2.00wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0154] In this application, Na2O is a network-external oxide that can provide free oxygen. An appropriate amount of Na2O helps improve the viscosity of the glass, promotes the melting and clarification of the glass liquid, increases the Na-K exchange in the glass, and achieves a high CS. However, excessive Na2O can affect the network structure of the glass, thereby affecting the stability of the glass. In some embodiments of this application, the Na2O content in the ultra-thin glass of varying thickness is 10.00 wt% to 18.00 wt%, preferably 12 wt% to 17 wt%, and more preferably 15 wt% to 17 wt%. For example, in terms of the mass percentage of oxide, the content of Na2O in the ultra-thin glass of unequal thickness can be 10.00wt%, 10.50wt%, 11.00wt%, 11.50wt%, 12.00wt%, 12.50wt%, 13.00wt%, 13.50wt%, 14.00wt%, 14.50wt%, 15.00wt%, 15.50wt%, 16.00wt%, 16.50wt%, 17.00wt%, 17.50wt% or 18.00wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0155] In this application, K2O is an oxide outside the glass network that affects the chemical strengthening effect of the glass. Therefore, in some embodiments of this application, the K2O content in the ultra-thin glass of varying thickness is 1.00 wt% to 6.00 wt%, preferably 2.0 wt% to 4.0 wt%, and more preferably 2.5 wt% to 3.50 wt%, calculated as a percentage by weight of the oxide. For example, in terms of the mass percentage of oxide, the content of K2O in the ultra-thin glass of unequal thickness can be 1.00 wt%, 1.20 wt%, 1.40 wt%, 1.60 wt%, 1.80 wt%, 2.00 wt%, 2.20 wt%, 2.40 wt%, 2.60 wt%, 2.80 wt%, 3.00 wt%, 3.20 wt%, 3.40 wt%, 3.60 wt%, 3.80 wt%, 4.00 wt%, 4.20 wt%, 4.40 wt%, 4.60 wt%, 4.80 wt%, 5.00 wt%, 5.20 wt%, 5.40 wt%, 5.60 wt%, 5.80 wt% or 6.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0156] In this application, Li2O is an oxide outside the glass network, which helps improve the Young's modulus, melt forming performance, and chemical strengthening properties of ultra-thin glass. Excessive Li2O content can significantly reduce the diffusivity of the glass. In some embodiments of this application, the Li2O content in ultra-thin glass of varying thickness, measured as a percentage of oxide by mass, is 0.00 wt% to 2.500 wt%, preferably 0.5 wt% to 1.5 wt%, and more preferably 0.6 wt% to 1.0 wt%. For example, in some embodiments of the present application, the content of Li2O in the ultra-thin glass of unequal thickness can be, in terms of the mass percentage of the oxide, 0.00 wt%, 0.10 wt%, 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, 0.90 wt%, 1.00 wt%, 1.10 wt%, 1.20 wt%, 1.30 wt%, 1.40 wt%, 1.50 wt%, 1.60 wt%, 1.70 wt%, 1.80 wt%, 1.90 wt%, 2.00 wt%, 2.10 wt%, 2.20 wt%, 2.30 wt%, 2.40 wt% or 2.50 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0157] In the glass system of the present application, MgO can reduce the forming temperature of the glass and improve the Young's modulus of the glass. Therefore, in some embodiments of the present application, the MgO content in the ultra-thin glass of unequal thickness is 3.00wt%-5.50wt% in terms of the mass percentage of the oxide; preferably 4.0wt%-5.5wt%, and more preferably 4.5wt%-4.9wt%. For example, in terms of the mass percentage of the oxide, the MgO content in the ultra-thin glass of unequal thickness can be 3.00wt%, 3.20wt%, 3.40wt%, 3.60wt%, 3.80wt%, 4.00wt%, 4.20wt%, 4.40wt%, 4.60wt%, 4.80wt%, 5.00wt%, 5.20wt%, 5.40wt% or 5.50wt%, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges.

[0158] In the glass system of the present application, B2O3 helps lower the melting temperature of the base glass, improving properties such as the glass's transmittance and overall uniformity. In some embodiments of the present application, the B2O3 content in the ultra-thin glass of varying thickness, measured as a percentage by mass of the oxide, is 0.10 wt% to 3.00 wt%, preferably 0.5 wt% to 2.0 wt%, and more preferably 0.8 wt% to 1.2 wt%. In some embodiments of the present application, the content of B2O3 in the ultra-thin glass of unequal thickness may be, in terms of mass percentage of oxide, 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.90 wt%, 1.00 wt%, 1.30 wt%, 1.50 wt%, 1.80 wt%, 2.00 wt%, 2.10 wt%, 2.30 wt%, 2.50 wt%, 2.70 wt%, 2.90 wt% or 3.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that, in an embodiment, any of the above ranges may be combined with any other ranges.

[0159] The fracture toughness, impact resistance and drop resistance of the ultra-thin glass of unequal thickness in this application are not only derived from the selection or non-selection of the above-mentioned components, but also require the control of the amount of Al2O3, Na2O, K2O, MgO, B2O3 and SiO2 to satisfy the following relationship:

[0160] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%

[0161] The fracture toughness of the obtained ultra-thin glass of unequal thickness can reach ≥0.76MPa·m 1 / 2 At the same time, the compressive stress of the strengthened ultra-thin glass of unequal thickness can reach more than 500MPa, which improves the impact resistance and drop resistance of the ultra-thin glass of unequal thickness.

[0162] For example, in some embodiments of the present application, the ratio of (Al2O3+Na2O+KO+MgO) / (BO3+SiO2) can be controlled at 52.00%, 53.00%, 54.00%, 55.00%, 56.00%, 57.00%, 58.00%, 59.00%, 60.00%, 61.00%, 62.00%, 63.00%, 64.00%, 65.00%, 66.00%, 67.00% or 68.00%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0163] The thickness of the unequal thickness ultra-thin glass provided in this application can be between 0.03mm and 0.35mm. The thickness of the unequal thickness ultra-thin glass here means that the minimum thickness of the unequal thickness ultra-thin glass can reach 0.03mm, and the maximum thickness can be 0.35mm. In other words, the minimum thickness of the unequal thickness ultra-thin glass can be as low as 0.03mm, and the maximum thickness can be 0.35mm.

[0164] In the present application, the thickness of the ultra-thin glass of unequal thickness can be 0.03mm~0.35mm, and its transmittance can reach ≥91.0%; in some preferred embodiments, the transmittance of the ultra-thin glass of unequal thickness obtained can reach above 91.5%, and in other more preferred embodiments, the transmittance of the ultra-thin glass of unequal thickness obtained can reach above 92%.

[0165] In this application, the fracture toughness of the ultra-thin glass of unequal thickness can reach ≥0.76MPa·m 1 / 2 In some preferred embodiments, the light transmittance of the obtained ultra-thin glass of unequal thickness can reach 0.78 MPa·m 1 / 2 In some more preferred embodiments, the light transmittance of the obtained ultra-thin glass of unequal thickness can reach 0.80 MPa·m 1 / 2 above.

[0166] In this application, the Vickers hardness of the ultra-thin glass of unequal thickness can reach ≥573kgf / mm 2 In some preferred embodiments, the Vickers hardness of the obtained ultra-thin glass of unequal thickness can reach 578kgf / mm 2 above.

[0167] In the present application, the average pen impact height of a single piece of the non-bending zone of the unequal thickness ultra-thin glass is 100-450 mm. Specifically, when the thickness L2 of the non-bending zone of the unequal thickness ultra-thin glass is 0.035 mm, the average pen impact height of the unequal thickness ultra-thin glass is not less than 100 mm. In some preferred embodiments, when the thickness L2 of the non-bending zone of the unequal thickness ultra-thin glass is 0.35 mm, the average pen impact height of the non-bending zone can reach 419 mm or more. Preferably, the average pen impact height of the non-bending zone can reach 170 mm or more.

[0168] In the present application, the average pen-drop impact height of the coating on the non-bending region of the unequal-thickness ultra-thin glass is 170-700 mm. Specifically, when the thickness L2 of the non-bending region of the unequal-thickness ultra-thin glass is 0.035 mm, the average pen-drop impact height of the coating on the unequal-thickness ultra-thin glass is not less than 170 mm. In some preferred embodiments, when the thickness L2 of the non-bending region of the unequal-thickness ultra-thin glass is 0.35 mm, the average pen-drop impact height of the coating on the non-bending region can reach over 632 mm.

[0169] The unequal thickness ultra-thin glass provided in this application has two design forms, such as Figure 1 and Figure 2 As shown, it includes two design forms: a bending zone is provided on the first surface of the glass and a bending zone is provided on both the first surface and the second surface of the glass. Figure 1 In the first form shown, a bending area is provided on the first surface of the glass, and two buffer zones connecting the two non-bending areas are symmetrically arranged; Figure 2 In the second form shown, bending areas are provided on the first surface and the second surface of the glass, and four buffer areas connecting the four non-bending areas are symmetrically arranged.

[0170] Among them, when the unequal thickness ultra-thin glass provided in this application is in the form of Figure 1 In the first form shown, the thickness L2 of the non-bending area is the maximum thickness Hmax of the unequal thickness ultra-thin glass; when the form of the unequal thickness ultra-thin glass provided by the present application is as follows Figure 2 In the second embodiment shown, the non-bending zone thickness L2 is half of the maximum thickness Hmax of the unequal-thickness ultra-thin glass. Specifically, the maximum thickness Hmax in this application is the maximum thickness from the first surface to the second surface of the unequal-thickness ultra-thin glass. The non-bending zone thickness L2 in this application is the maximum distance from the surface of the unequal-thickness ultra-thin glass where each bending zone exists to the plane where the bottom surface of the corresponding bending zone lies. For bending zones on both the first and second surfaces of the unequal-thickness ultra-thin glass, the plane where the bottom surface of each bending zone lies is the plane of symmetry of the two symmetrically arranged bending zones.

[0171] When the sizes of the non-bending zone, bending zone and buffer zone of the ultra-thin glass of unequal thickness provided in the present application satisfy the following formula: 0.301≤10×d / W+0.01×A×W≤0.929, that is, when the value of B in B=10×d / W+0.01×A×W is in the range of 0.301-0.929, the maximum bending radius R(2PB) of the ultra-thin glass of unequal thickness provided in the present application can reach 0.2~2.05mm. A is the depth-to-width ratio of the buffer zone of the unequal thickness ultra-thin glass product, calculated as follows: A = 100 × (c / a); a is the width of the buffer zone; c is the depth of the buffer zone; A ranges from 0.022 to 2.286; d is the thickness of the bending zone; W is the ratio of the thickness of the non-bending zone to the maximum thickness Hmax, calculated as follows: W = L2 / Hmax, with a value of 0.5 or 1.0; L2 is the thickness of the non-bending zone of the unequal thickness ultra-thin glass, and Hmax is the maximum thickness of the unequal thickness ultra-thin glass. In this application, Hmax is generally within the range of 0.07 to 0.35 mm; the thickness of the non-bending zone of the unequal thickness ultra-thin glass is generally between 0.035 and 0.35 mm. For example, the ratio W of the thickness of the non-bending area to the maximum thickness Hmax can be 0.50 or 1.00. It should be noted that when the thickness of the non-bending area is equal to Hmax, that is, when the W value is 1, the structure of the unequal thickness ultra-thin glass is as follows: Figure 1 When the thickness L2 of the non-bending area is not equal to Hmax, that is, when the W value is 0.5, the structure of the ultra-thin glass of unequal thickness is as shown in FIG. Figure 2 As shown, when W is 0.5, bending zones, non-bending zones, and buffer zones are provided on both sides of the overall thickness direction of the unequal thickness ultra-thin glass. It should be noted that the thickness of the non-bending zones is always greater than that of the bending zones to form a unequal thickness glass product.

[0172] The B value of the ultra-thin glass of unequal thickness provided herein may be, for example, 0.301, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, or 0.929, and all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges. The B value is preferably 0.300 to 0.850, more preferably 0.400 to 0.700.

[0173] In some preferred embodiments, the ultimate bending radius R(2PB) of the unequal thickness ultra-thin glass can reach 0.2 to 2.05 mm. When the thickness of the bending zone of the unequal thickness ultra-thin glass is 0.03 mm, the ultimate bending radius R(2PB) of the unequal thickness ultra-thin glass is 0.20 to 0.55 mm; when the thickness of the bending zone of the unequal thickness ultra-thin glass is 0.07 mm, the ultimate bending radius R(2PB) of the unequal thickness ultra-thin glass is 1.75 to 2.05 mm.

[0174] The relationship between the dimensions of the buffer zone and the bending zone of the unequal thickness ultra-thin glass provided in this application is as follows: when the value of b + 0.1 / A is in the range of 7.044-29.500, that is, when the value of C in C = b + 0.1 / A is in the range of 7.044-29.500, the unequal thickness ultra-thin glass can have a bending distance of 3-13 mm, and its bending life R0.8-R1.8 can reach more than 200,000 times. Where A is the depth-to-width ratio of the buffer zone of the unequal thickness ultra-thin glass product, and is calculated as: Ratio A = 100 * (c / a); where a is the width of the buffer zone; c is the depth of the buffer zone; and b is the width of the bending zone.

[0175] The C value range of the unequal thickness ultra-thin glass provided herein can be illustratively 11.00, 11.50, 12.00, 12.50, 13.00, 13.50, 14.00, 14.50, 15.00, 15.50, 16.00, 16.50, 17.00, 17.50, 18.00, 18.50, 19.00, 19.50, 20.00 or 20.50, and all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges. Its C value is preferably 8.00 to 25.00, more preferably 12.00 to 20.00.

[0176] In some preferred embodiments, when the thickness of the bending zone of the unequal thickness ultra-thin glass is 0.03 mm, its offset bending distance can reach 3.05 to 12.95 mm, and its bending life R0.8 can reach more than 200,000 times; when the thickness of the bending zone of the unequal thickness ultra-thin glass is 0.07 mm, its offset bending distance can reach 3.20 to 12.50 mm, and its bending life R2.5 can reach more than 200,000 times.

[0177] In the present application, the width a of the buffer zone and the width b of the bending zone of the unequal thickness ultra-thin glass are not particularly limited in this application, and they can meet the value ranges required by the above-mentioned B value and C value. For example, the width a of the buffer zone of the unequal thickness ultra-thin glass can be 14-45 mm; preferably 20-40 mm. In some embodiments of the present application, the width a of the buffer zone of the unequal thickness ultra-thin glass can be 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, 44 mm or 45 mm, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges. For example, the width b of the bending zone of the unequal thickness ultra-thin glass can be 7-25 mm; preferably 10-15 mm. In some embodiments of the present application, the width b of the bending zone of the ultra-thin glass of unequal thickness can be 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, or 25 mm, and all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges.

[0178] In the present application, the depth c of the buffer zone and the thickness d of the bending zone of the unequal thickness ultra-thin glass are not particularly limited in this application, and they can meet the value ranges required by the above-mentioned B value and C value. For example, the depth c of the buffer zone of the unequal thickness ultra-thin glass can be 0.02-0.32mm; preferably 0.07-0.25mm. In some embodiments of the present application, the depth c of the buffer zone of the unequal thickness ultra-thin glass can be 0.02mm, 0.04mm, 0.06mm, 0.08mm, 0.10mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.20mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.30mm or 0.32mm, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges. For example, the thickness d of the bending zone of the unequal thickness ultra-thin glass can be 0.015-0.07 mm, preferably 0.015-0.05 mm. In some embodiments of the present application, the thickness d of the bending zone of the unequal thickness ultra-thin glass can be 0.015 mm, 0.020 mm, 0.025 mm, 0.030 mm, 0.035 mm, 0.040 mm, 0.045 mm, 0.050 mm, 0.055 mm, 0.060 mm, 0.065 mm, 0.070 mm, 0.075 mm, 0.080 mm, 0.085 mm, 0.090 mm, 0.095 mm or 0.100 mm, and all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges.

[0179] In a second aspect, the present application provides a method for preparing the ultra-thin glass of unequal thickness as described above, comprising the following steps:

[0180] Step 1: Providing ultra-thin base glass;

[0181] Step 2: chemically etching the ultra-thin base glass provided in step 1 to obtain ultra-thin glasses of varying thicknesses;

[0182] Step 3: Chemically strengthen the ultra-thin glass of unequal thickness provided in step 2 to obtain strengthened ultra-thin glass of unequal thickness.

[0183] The components of the ultra-thin base glass, calculated in terms of mass percentage of oxides, include the following components:

[0184] SiO2: 55.0-65.0%;

[0185] Al2O3: 15.0-20.0%;

[0186] Li2O: 0-2.5%;

[0187] Na2O: 10-18.0%;

[0188] K2O: 1-6%;

[0189] MgO: 3-5.5%;

[0190] CaO: 0-1%;

[0191] Y2O3: 0-1%;

[0192] ZrO2: 0.1-2.0%;

[0193] B2O3: 0.1-3.0%;

[0194] Among them, each component satisfies the following relationship:

[0195] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%;

[0196] Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

[0197] In order to provide a basic glass that meets sufficient fracture toughness, impact resistance, drop resistance and bending resistance, and at the same time, by controlling the ratio and relationship of each component, the etching and strengthening process is controlled, so that the fracture resistance, impact resistance, drop resistance and bending resistance of the ultra-thin glass of unequal thickness obtained after etching and strengthening can meet the requirements.

[0198] In the preparation method of the present application, the preparation of ultra-thin base glass adopts existing raw materials mixed for more than 30 minutes, and then obtains it through melting, annealing, and molding processes. In the preparation method of the present application, the melting temperature is 1350℃-1700℃, and the melting time is 4h-240h. In some embodiments of the present application, the melting temperature can be 1350℃, 1400℃, 1450℃, 1500℃, 1550℃, 1600℃, 1650℃ or 1700℃, etc., and all ranges and sub-ranges between the above values. In some embodiments of the present application, the melting time can be 4h, 8h, 16h, 32h, 48h, 60h, 72h, 100h, 160h, 200h, 220h or 240h, etc., and all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges. In the preparation method of the present application, the temperature of the annealing treatment is 550°C-650°C, and the time of the annealing treatment is 0.5min-2000min. In some embodiments of the present application, the temperature of the annealing treatment can be 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 640°C, or 650°C, etc., and all ranges and sub-ranges between the above values. In some embodiments of the present application, the time of the annealing treatment can be 0.5min, 1min, 10min, 30min, 100min, 200min, 400min, 800min, 1000min or 2000min, etc., and all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0199] After annealing, the substrate glass is prepared using a conventional molding method, which is not limited in this application. For example, the substrate glass can be molded using methods including, but not limited to, slot draw, overflow draw, secondary drawing, casting and rolling, casting fused brick, and float glass. The composition of the ultra-thin substrate glass in this application is the same as that of the resulting ultra-thin glass of varying thickness.

[0200] In the present application, the thickness of the prepared ultra-thin base glass is 0.03-0.55 mm, and the total thickness deviation TTV is preferably controlled to be no more than 5 μm.

[0201] In the preparation method of the present application, before step 2, in order to obtain glass of a predetermined size, the ultra-thin base glass is usually cut into a predetermined size before step 2 is performed. The cutting of ultra-thin base glass is usually laser cutting or other existing technologies that can achieve ultra-thin base glass cutting, and the present application does not limit this. For example, the ultra-thin base glass provided in the present application is cut into 200mm*200mm glass samples, and the total thickness deviation TTV of the cut glass sheets is ≤5μm. It should be noted that the total thickness deviation TTV in the present application refers to the difference between the maximum thickness and the minimum thickness on the same piece of glass product, which can be used to indicate the uniformity of the thickness of the same glass product. In the present application, the total thickness deviation TTV of the glass sample with a size of 200mm*200mm is not higher than 15% of the maximum thickness of the glass, and preferably the total thickness deviation TTV is ≤5μm.

[0202] Since the present application provides ultra-thin glass of unequal thickness, it is necessary to etch and thin the glass in a specific area in the preparation method. In step 2, the specific glass area is etched and thinned. Any of the existing mask method, mold method or directional guide method can be used to ensure that the etching liquid only etches the specific area of ​​the ultra-thin base glass.

[0203] The mask method is selected from a yellow light mask method and a coating method; the mold method is selected from an arc mold fixed etching method; and the directional flow guide method is selected from a precision liquid flow guided etching method and a forward and reverse pulling method. These methods are all existing technologies and will not be described in detail in this application.

[0204] In step 2 of the present application, the chemical etching includes chemically etching the fixed area of ​​the ultra-thin base glass using a first etching solution, and the chemical etching method is selected from top-spray chemical etching or immersion chemical etching. The first etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride; the etching temperature during chemical etching is 20°C to 50°C; and the etching rate during chemical etching is 0.1 μm / min to 20 μm / min. In some embodiments of the present application, the etching temperature of the first etching solution can be 20°C, 25°C, 30°C, 35°C, 35°C, 45°C, 45°C or 50°C, etc., and the etching rate can be 0.1μm / min, 0.2μm / min, 0.5μm / min, 1.0μm / min, 2μm / min, 5μm / min, 10μm / min, 15μm / min or 20μm / min, etc., and the concentration of the first etching solution can be 0.5wt% to 3.0wt%. For example, the concentration of the solute in the etching solution can be 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt%, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0205] In the preparation method of the present application, the ultra-thin glass after chemical etching enters the edge processing step. The edge processing step specifically includes the following steps:

[0206] Coating the two main surfaces of the ultra-thin glass sheets of unequal thickness with a specific strong acid-resistant ink to protect the main surfaces of the ultra-thin glass sheets of unequal thickness, and then using a second etching solution to perform edge treatment on the glass products of unequal thickness that have undergone the chemical etching process;

[0207] The second etching solution is selected from one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride.

[0208] In the edge processing step, the etching temperature of the second etching solution can be 20°C to 50°C. For example, the etching temperature can be 20°C, 25°C, 30°C, 35°C, 35°C, 45°C, 45°C or 50°C, etc. The etching temperature of the second etching solution can be 0.1μm / min to 10μm / min; for example, the etching rate can be 0.1μm / min, 0.2μm / min, 0.5μm / min, 1.0μm / min, 2μm / min, 5μm / min, 10μm / min, 15μm / min or 20μm / min, etc. The etching time of the second etching solution can be 1min to 10min; for example, the etching rate can be 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min, etc., and all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0209] The two main surfaces of the unequal thickness ultra-thin glass refer to the two surfaces with the largest areas in the length and width directions of the unequal thickness ultra-thin glass. Before the edge treatment process, the main surfaces of the unequal thickness ultra-thin glass are protected with a strong acid-resistant ink so that the main surfaces are not affected during the edge treatment process.

[0210] In the present application, the process of protecting the main surface of ultra-thin glass of unequal thickness with strong acid-resistant ink is usually performed after the ultra-thin base glass is prepared and before the ultra-thin base glass is cut.

[0211] The strong acid-resistant ink used is an existing material that can protect the surface of ultra-thin glass during the etching process, and its specific selection is not limited in this application. In addition, the strong acid-resistant ink can be applied to the surface of the ultra-thin base glass through any existing coating process, such as scraping or brushing, and the specific coating process is not limited in this application.

[0212] In the preparation method of the present application, after the unequal thickness ultra-thin glass edge treatment process, it also includes a strong acid-resistant ink removal process; the strong acid-resistant ink removal process includes using an alkaline solution to remove the strong acid-resistant ink from the unequal thickness glass products that have undergone the edge treatment process.

[0213] Among them, the alkaline solution used to remove strong acid-resistant ink is selected from NaOH, NaHCO3, Na2CO3, C6H 11 NaO7、C6H 15 One or more types of NO3.

[0214] In the preparation method of the present application, the chemical strengthening includes a first chemical strengthening step and a second chemical strengthening step;

[0215] The temperature of the molten salt bath used in the first chemical strengthening process is 380°C to 550°C, and the chemical strengthening time is 5 minutes to 240 minutes. In some embodiments of the present application, the chemical strengthening temperature can be 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C or 550°C, and all ranges and sub-ranges between the above values. In some embodiments of the present application, the chemical strengthening time of the first chemical strengthening process can be 5 minutes, 10 minutes, 20 minutes, 40 minutes, 60 minutes, 80 minutes, 120 minutes, 140 minutes, 160 minutes, 180 minutes, 200 minutes, 220 minutes or 240 minutes, and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges. The molten salt used in the molten salt bath includes 0-50 wt% sodium salt, 40-100 wt% potassium salt, and 0-10 wt% lithium salt; wherein the lithium salt is one or more of lithium nitrate and lithium sulfate; the sodium salt is one or more of sodium nitrate, sodium sulfate, and sodium carbonate; and the potassium salt is one or more of potassium nitrate, potassium sulfate, and potassium carbonate.

[0216] The first chemical strengthening step may be a single chemical strengthening treatment or multiple chemical strengthening treatments. When multiple chemical strengthening treatments are used, the molten salt bath temperature is also 380°C to 550°C, and the sum of the multiple chemical strengthening treatment times is not less than the time of a single chemical strengthening treatment. Preferably, the first chemical strengthening step uses multiple chemical strengthening treatments, with the time difference between each adjacent chemical strengthening treatment being 10 minutes to 20 minutes.

[0217] In the preparation method of the present application, the second chemical strengthening process includes placing the ultra-thin glass products of unequal thickness that have undergone the first chemical strengthening process in a third etching solution for 60s to 1200s to obtain ultra-thin glass of unequal thickness; wherein the third etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride.

[0218] After the second chemical strengthening step, those skilled in the art may further perform other conventional steps to obtain ultra-thin glass products of varying thicknesses that meet desired specifications or requirements, such as surface cleaning requirements.

[0219] In a third aspect, the present application further provides an ultra-thin base glass for preparing the ultra-thin glass of unequal thickness described in the first aspect, wherein the ultra-thin base glass has a thickness of 0.03-0.55 mm and comprises the following components, calculated in terms of the mass percentage of oxides:

[0220] SiO2: 55.0-65.0%;

[0221] Al2O3: 15.0-20.0%;

[0222] Li2O: 0-2.5%;

[0223] Na2O: 10-18.0%;

[0224] K2O: 1-6%;

[0225] MgO: 3-5.5%;

[0226] CaO: 0-1%;

[0227] Y2O3: 0-1%;

[0228] ZrO2: 0.1-2.0%;

[0229] B2O3: 0.1-3.0%;

[0230] Among them, each component satisfies the following relationship:

[0231] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%;

[0232] Wherein, the ultra-thin base glass does not contain ZnO, P2O5 and SrO.

[0233] In the present application, "the ultra-thin base glass does not contain ZnO, P2O5 and SrO" should be understood as that when providing the raw materials for preparing the ultra-thin base glass of the present application, salts or elements containing ZnO, P2O5 and SrO or capable of forming oxides of ZnO, P2O5 and SrO are not actively added, and the content of impurities such as ZnO, P2O5 and SrO in other raw materials used is also controlled so that the total content of ZnO, P2O5 and SrO in the obtained ultra-thin base glass is not higher than 0.5%.

[0234] The applicant has found that when a certain amount of ZnO, P2O5 and SrO are present in the ultra-thin base glass, it will affect the performance of the unequal thickness ultra-thin glass formed after etching and strengthening, especially the fracture toughness and bending performance of the obtained unequal thickness ultra-thin glass. The reason may be that the buffer area and bending area of ​​the unequal thickness ultra-thin glass usually need to be chemically etched and thinned by an etchant containing fluorine elements, and ZnO, as a typical network intermediate often used in glass, easily forms a zinc fluorosilicate product with strong adhesion during the etching process of the fluorine-containing etchant, which hinders the chemical etching on the etched glass surface, thereby causing surface defects such as concave and convex points to form on the etched surface, affecting the performance of the bending area and buffer zone; in addition, the addition of ZnO, especially a large amount of ZnO, may also increase the CTE and have a problem of strengthening warping, and ZnO lowering the strain point may have a negative effect on chemically tempered glass, low-temperature relaxation will weaken the stability of the surface compressive stress layer, and a small amount of zinc oxide will cause a steeper stress distribution, reducing the stability of the bending performance. PO is a typical network former. Although it can independently construct a glass network based on [PO] tetrahedron, the increase in PO content leads to a loose network and reduces structural stability. In the glass network system provided in the present application, if a phosphate glass network is formed, the POP bonds therein are easily hydrolyzed, resulting in a significant deterioration of water resistance (especially in an environment with pH>7). The surface of ultra-thin glass is prone to dissolution, forming microcracks and accelerating strength decay; in addition, PO is prone to cause metastable phase separation, and the risk of crystallization is high, which is not conducive to production. In addition, SrO has a larger ionic radius than MgO and CaO, so that the ultra-thin glass of unequal thickness formed has a larger thermal expansion coefficient, which reduces its thermal shock resistance and makes it prone to warping and wrinkling defects during high-temperature strengthening.

[0235] In order to further improve the performance of the unequal thickness ultra-thin glass provided in this application, the ultra-thin base glass provided in this application does not contain SnO.

[0236] Similarly, in the present application, "the ultra-thin base glass does not contain SnO2" should be understood as that when providing the raw materials for preparing the ultra-thin base glass of the present application, no salt or element containing SnO2 or capable of forming oxides such as SnO2 is actively added, and the content of impurities such as SnO2 in other raw materials used is also controlled so that the content of SnO2 in the obtained ultra-thin base glass is not higher than 0.5%.

[0237] It should be noted that the raw materials here refer to the main ingredients in the formula that forms the ultra-thin base glass, and not other additives and auxiliary agents added during the production process of ultra-thin glass of varying thicknesses for processing purposes, such as clarifiers and molten salts used for etching and strengthening. Therefore, the statement in this application that "the ultra-thin base glass does not contain SnO2" should be understood as meaning that SnO2 and salts or elements that can form SnO2 oxide are not actively added to the main ingredients in the formula that forms the ultra-thin base glass.

[0238] The applicant has found that when a certain amount of SnO2 exists in the ultra-thin base glass, it is not conducive to the coloring performance and light transmittance of the tempered glass formed based on the ultra-thin base glass. The reason may be that during the ion strengthening process, the SnO2 on the lower surface of the ultra-thin glass 4+ It is easy to cause differences in expansion increments, thereby causing bending deformation, and may produce light interference rainbow fringes, and react with the rhodium in the container during the production process, reducing the coloring properties and visible light transmittance of the formed ultra-thin glass of unequal thickness.

[0239] It should be noted that, during the preparation process of ultra-thin base glass, tin oxide can be appropriately added as a clarifier, resulting in the ultra-thin base glass containing a small amount of SnO2. This situation is not considered to be inconsistent with the statement in this application that "the ultra-thin base glass does not contain SnO2".

[0240] In the present application, SiO2 is an oxide that forms the glass network skeleton and is used to stabilize the network structure of the base glass. Excessive SiO2 content can cause the glass's solubility to deteriorate or increase the viscosity of the molten glass, making it difficult to clarify and forming the glass. In some embodiments of the present application, the SiO2 content in the ultra-thin base glass, measured as a percentage by mass of the oxide, is between 55.00 wt% and 66.00 wt%, preferably between 58 wt% and 62 wt%, and more preferably between 59 wt% and 61 wt%. For example, in terms of the mass percentage of oxide, the content of SiO2 in the ultra-thin base glass can be: 55.00 wt%, 55.50 wt%, 56.00 wt%, 56.50 wt%, 57.00 wt%, 57.50 wt%, 58.00 wt%, 58.50 wt%, 59.00 wt%, 59.50 wt%, 60.00 wt%, 60.50 wt%, 61.00 wt%, 61.50 wt%, 62.00 wt%, 62.50 wt%, 63.00 wt%, 63.50 wt%, 64.00 wt%, 64.50 wt%, 65.00 wt%, 65.50 wt% or 76.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0241] In this application, Al2O3 can be used to construct the glass skeleton, supplementing the network. The ion exchange rate can also be adjusted by varying the size of the space within the glass network for ion exchange. However, if the Al2O3 content is too high, the melting and operating temperatures of the glass will be very high, easily leading to crystallization and poor transparency and flexibility. In some embodiments of this application, the Al2O3 content in the ultra-thin base glass, measured as a percentage by mass of the oxide, is 15.00 wt% to 20.00 wt%, preferably 16.5 wt% to 18 wt%, and more preferably 17 wt% to 18 wt%. Illustratively, the content of Al2O3 in the ultra-thin base glass, measured in percentage by mass of oxide, may be 15.00 wt%, 15.20 wt%, 15.40 wt%, 15.60 wt%, 15.80 wt%, 16.00 wt%, 16.20 wt%, 16.40 wt%, 16.60 wt%, 16.80 wt%, 17.00 wt%, 17.20 wt%, 17.40 wt%, 17.60 wt%, 17.80 wt%, 18.00 wt%, 18.20 wt%, 18.40 wt%, 18.60 wt%, 18.80 wt%, 19.00 wt%, 19.20 wt%, 19.40 wt%, 19.60 wt%, 19.80 wt% or 20.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0242] In this application, CaO is a glass network-external oxide that can lower the glass forming temperature and improve the glass's Young's modulus and strength. In some embodiments of this application, the CaO content in the ultra-thin base glass, calculated as a percentage by mass of the oxide, is 0.00 wt% to 1.00 wt%, preferably 0 wt% to 0.8 wt%, and more preferably 0.1 wt% to 0.5 wt%. For example, in terms of the mass percentage of oxide, the CaO content in the ultra-thin base glass may be 0.00 wt%, 0.05 wt%, 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, 0.35 wt%, 0.40 wt%, 0.45 wt%, 0.50 wt%, 0.55 wt%, 0.60 wt%, 0.65 wt%, 0.70 wt%, 0.75 wt%, 0.80 wt%, 0.85 wt%, 0.90 wt%, 0.95 wt% or 1.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0243] In this application, ZrO2 acts as a network intermediate. An appropriate amount of ZrO2 can increase the viscosity, Young's modulus, refractive index, and chemical stability of the glass and reduce the thermal expansion coefficient of the glass. However, excessive ZrO2 can increase the difficulty of melting the base glass and cause crystallization. In some embodiments of this application, the ZrO2 content in the ultra-thin base glass is 0.10 wt% to 2.00 wt%, preferably 0.5 wt% to 1.5 wt%, and more preferably 0.5 wt% to 1.0 wt%, as a percentage by mass of the oxide. For example, the content of ZrO2 in the ultra-thin base glass can be 0.10 wt%, 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, 0.90 wt%, 1.00 wt%, 1.10 wt%, 1.20 wt%, 1.30 wt%, 1.40 wt%, 1.50 wt%, 1.60 wt%, 1.70 wt%, 1.80 wt%, 1.90 wt% or 2.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0244] In this application, Na2O is a network-external oxide that can provide free oxygen. An appropriate amount of Na2O helps improve the viscosity of the glass, promotes the melting and clarification of the glass liquid, increases the Na-K exchange in the glass, and achieves a high CS. However, excessive Na2O can affect the network structure of the glass, thereby affecting the stability of the glass. In some embodiments of this application, the Na2O content in the ultra-thin base glass is 10.00 wt% to 18.00 wt%, preferably 12 wt% to 17 wt%, and more preferably 15 wt% to 17 wt%. For example, in terms of the mass percentage of oxide, the content of Na2O in the ultra-thin glass of unequal thickness can be 10.00wt%, 10.50wt%, 11.00wt%, 11.50wt%, 12.00wt%, 12.50wt%, 13.00wt%, 13.50wt%, 14.00wt%, 14.50wt%, 15.00wt%, 15.50wt%, 16.00wt%, 16.50wt%, 17.00wt%, 17.50wt% or 18.00wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0245] In this application, K₂O is an oxide outside the glass network that affects the chemical strengthening effect of the glass. Therefore, in some embodiments of this application, the K₂O content in the ultra-thin base glass, calculated as a percentage by mass of the oxide, is 1.00 wt% to 6.00 wt%; preferably 2.0 wt% to 4.0 wt%, and more preferably 2.5 wt% to 3.50 wt%. For example, in terms of the mass percentage of oxide, the content of KO in the ultra-thin base glass can be 1.00 wt%, 1.20 wt%, 1.40 wt%, 1.60 wt%, 1.80 wt%, 2.00 wt%, 2.20 wt%, 2.40 wt%, 2.60 wt%, 2.80 wt%, 3.00 wt%, 3.20 wt%, 3.40 wt%, 3.60 wt%, 3.80 wt%, 4.00 wt%, 4.20 wt%, 4.40 wt%, 4.60 wt%, 4.80 wt%, 5.00 wt%, 5.20 wt%, 5.40 wt%, 5.60 wt%, 5.80 wt% or 6.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0246] In this application, Li2O is an oxide outside the glass network, which helps improve the Young's modulus, melt forming performance, and chemical strengthening properties of ultra-thin glass. Excessive Li2O content can significantly reduce the diffusivity of the glass. In some embodiments of this application, the Li2O content in the ultra-thin base glass, measured as a percentage by mass of the oxide, is 0.00 wt% to 2.500 wt%, preferably 0.5 wt% to 1.5 wt%, and more preferably 0.6 wt% to 1.0 wt%. For example, in some embodiments of the present application, the content of Li2O in the ultra-thin base glass, calculated as a percentage by mass of oxide, may be: 0.00 wt%, 0.10 wt%, 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, 0.90 wt%, 1.00 wt%, 1.10 wt%, 1.20 wt%, 1.30 wt%, 1.40 wt%, 1.50 wt%, 1.60 wt%, 1.70 wt%, 1.80 wt%, 1.90 wt%, 2.00 wt%, 2.10 wt%, 2.20 wt%, 2.30 wt%, 2.40 wt% or 2.50 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0247] In the glass system of the present application, MgO can reduce the forming temperature of the glass and improve the Young's modulus of the glass. Therefore, in some embodiments of the present application, the MgO content in the ultra-thin base glass is 3.00wt%-5.50wt% in terms of the mass percentage of the oxide; preferably 4.0wt%-5.5wt%, and more preferably 4.5wt%-4.9wt%. For example, in terms of the mass percentage of the oxide, the MgO content in the ultra-thin glass of varying thickness can be 3.00wt%, 3.20wt%, 3.40wt%, 3.60wt%, 3.80wt%, 4.00wt%, 4.20wt%, 4.40wt%, 4.60wt%, 4.80wt%, 5.00wt%, 5.20wt%, 5.40wt% or 5.50wt%, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiments, any of the above ranges can be combined with any other ranges.

[0248] In the glass system of the present application, B2O3 helps lower the melting temperature of the base glass, improving properties such as transmittance and overall uniformity. In some embodiments of the present application, the B2O3 content in the ultra-thin base glass, measured as a percentage by mass of the oxide, is 0.10 wt% to 3.00 wt%, preferably 0.5 wt% to 2.0 wt%, and more preferably 0.8 wt% to 1.2 wt%. In some embodiments of the present application, the content of B2O3 in the ultra-thin base glass, calculated as a percentage by mass of oxide, may be: 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.90 wt%, 1.00 wt%, 1.30 wt%, 1.50 wt%, 1.80 wt%, 2.00 wt%, 2.10 wt%, 2.30 wt%, 2.50 wt%, 2.70 wt%, 2.90 wt% or 3.00 wt%, etc., and all ranges and sub-ranges between the above values. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0249] The fracture toughness, impact resistance and drop resistance of the ultra-thin base glass in this application are not only derived from the selection or non-selection of the above components, but also require the control of the amount of Al2O3, Na2O, K2O, MgO, B2O3 and SiO2 to satisfy the following relationship:

[0250] 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%

[0251] The fracture toughness of the ultra-thin base glass can reach ≥0.76MPa·m 1 / 2 At the same time, the compressive stress of the strengthened ultra-thin base glass can reach more than 500MPa, which improves the impact resistance and drop resistance of the ultra-thin base glass.

[0252] For example, in some embodiments of the present application, the ratio of (Al2O3+Na2O+KO+MgO) / (BO3+SiO2) can be controlled at 52.00%, 53.00%, 54.00%, 55.00%, 56.00%, 57.00%, 58.00%, 59.00%, 60.00%, 61.00%, 62.00%, 63.00%, 64.00%, 65.00%, 66.00%, 67.00% or 68.00%, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0253] The thickness of the ultra-thin base glass provided in the present application may be 0.03 mm to 0.55 mm, and its total thickness deviation TTV is ≤ 5 μm when the length and width are 200 mm*200 mm.

[0254] In a fourth aspect, the present application provides an application of the ultra-thin glass of unequal thickness as described in the first aspect or the ultra-thin glass of unequal thickness prepared by the preparation method of the ultra-thin glass of unequal thickness as described in the second aspect in automobile displays or windows, foldable electronic devices, aerospace window glass, aviation radiation-resistant glass, advertising display screens, building curtain walls, and furniture decoration.

[0255] In a fifth aspect, the present application further provides a foldable electronic device, comprising the ultra-thin glass of unequal thickness as described in the first aspect or the ultra-thin glass of unequal thickness prepared by the method for preparing ultra-thin glass of unequal thickness as described in the second aspect. In the present application, the electronic device comprises a housing and a middle frame; the housing comprises the ultra-thin glass of unequal thickness or the ultra-thin glass of unequal thickness prepared by the method for preparing ultra-thin glass of unequal thickness. The foldable electronic device can be at least one of any mobile phone, tablet computer, handheld game console, car central control, smart home, etc. that can be configured as a foldable screen.

[0256] In order to facilitate those skilled in the art to better understand the innovative features of the present application, the technical solutions of the present application are further described in detail below in conjunction with the embodiments. The embodiments of the present application described in detail below are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0257] Example 1 (S1)

[0258] According to the formula of Example 1 in Table 1, the raw material components were accurately weighed in proportion and thoroughly mixed for 30 minutes to obtain a mixture, the total weight of the raw material components being 2000 g. The mixture was placed in a melting vessel and heated to 1650° C. in a high-temperature melting furnace for 20 hours to melt, thereby obtaining an ultra-thin substrate glass.

[0259] Laser cutting was then used to cut the glass into 200mm x 200mm glass samples. Using an immersion chemical etcher, forward and reverse pull etching was performed to create the specific ultra-thin glass shapes with unequal thicknesses (a, b, c, and d) as shown in Table 3. The etching solutions consisted of HF (volume fraction 1.8%-1.9%), H2SO4 (volume fraction 0.8%-0.9%), HNO3 (volume fraction 0.7%-0.8%), and water. The etching temperature was controlled at 30°C and the etching rate was kept at 0.5μm / min. The ultra-thin glass sheets, which had been etched to achieve the designed bending and buffer zones, were edge-treated. A transparent fluorescent resin, acid-resistant ink, was applied to both main surfaces of the ultra-thin glass sheets using a screen-printed protective ink. Chemical etching was then performed using the etching solutions: HF (volume fraction 0.6%-0.7%), H2SO4 (volume fraction 0.5%-0.6%), HNO3 (volume fraction 0.4%-0.5%), and water. The treatment time is 120s, the etching temperature is controlled at 65°C, and the etching rate is 0.2μm / min. After the edge chamfer is etched, deinking is performed. The deinking process uses: 0.5%-1% NaOH by volume, 0.3%-0.5% NaHCO3 by volume, and the rest is water. The deinking temperature is controlled at 75°C, and the treatment time is 10min. After deinking, strengthening is carried out in 10% NaNO3 + 90% KNO3 at 390°C for 20min. After strengthening, a chemical surface strengthening process is performed to passivate microcracks. The etching solution includes: HF (volume fraction 0.5%-1.0%), H2SO4 (volume fraction 0.5%-1.0%), HNO3 (volume fraction 0.1%-0.6%), and the rest is water. The etching temperature is controlled at 20°C to 35°C, and the etching time is 60s.

[0260] Example 2 to Example 8 (S2 to S8)

[0261] The operation was carried out under the same conditions as in Example 1, except that the raw material compositions of the ultra-thin base glass shown in Table 1 and the a, b, c, d values, L2 and Hmax values ​​of the ultra-thin glass of unequal thickness shown in Table 3 were used.

[0262] Comparative Example 1 to Comparative Example 12 (D1 to D12)

[0263] The operation was carried out under the same conditions as in Example 1, except that the raw material compositions of the ultra-thin base glass shown in Table 2 and the values ​​of a, b, c, d, L2 and Hmax of the ultra-thin glasses of unequal thickness shown in Table 4 were controlled.

[0264] The performance tests were performed on the ultra-thin glasses of unequal thickness obtained in Examples 1 to 8 and Comparative Examples 1 to 12, and the result data are shown in Table 1, Table 2, Table 5 and Table 6, respectively.

[0265] As can be seen from Tables 1 and 2, 5 and 6, by adopting the formula composition provided in the present application and controlling the relationship between the components to satisfy Formula I, the ultra-thin glass of unequal thickness provided in the present application can have higher surface compressive stress, Vickers hardness and fracture toughness while ensuring its light transmittance. The surface compressive stress can reach 500 MPa and the Vickers hardness can reach 578 kgf / mm 2 At the same time, its fracture toughness can reach 0.78MPa·m 1 / 2 While the ultra-thin glass of unequal thickness prepared using the formula used in Comparative Example 3 can also achieve the aforementioned Vickers hardness and fracture toughness, its light transmittance decreases. As can be seen from Tables 5 and 6, its impact resistance and bending performance also decrease significantly. This may be due to the fact that the content of Na ions available for ion exchange in Comparative Example 3 is relatively low, resulting in a relatively low surface compressive stress. Surface compressive stress (CS) is a key barrier to resisting external tensile stress. Therefore, when CS is low (e.g., <500 MPa), the peak surface tensile stress of the glass is more likely to exceed the fracture limit when bent, leading to surface microcracks (e.g., scratches) that are more likely to expand under bending stress. Consequently, bending properties such as the ultimate bending radius and bending life are poor. Similarly, glass with low surface compressive stress can withstand smaller external impact loads, has a reduced impact energy absorption capacity, and primarily relies on brittle fracture. Furthermore, the crack propagation threshold is lowered, and impact resistance is sharply reduced, resulting in lower average single-piece pen impact height and average film-coated pen impact height.

[0266] As can be seen from Tables 5 and 6, the unequal thickness ultra-thin glass provided by the present application not only has good light transmittance, Vickers hardness, and fracture toughness, but also has good impact resistance and bending performance. In particular, when the values ​​of a, b, c, d, L2, and Hmax are controlled to satisfy the structural formulas shown in A, B, and C, the impact resistance and bending performance can be further improved to obtain unequal thickness ultra-thin glass with better performance. In particular, the unequal thickness ultra-thin glass designed based on the above formula and morphology can obtain unequal thickness ultra-thin glass with lower bending zone thickness within a certain range, and the ultimate bending radius of the unequal thickness ultra-thin glass is significantly reduced, which can adapt to application scenarios that are more sensitive to bending, such as folding mobile phone devices under lightweight and thinness. At the same time, the unequal thickness ultra-thin glass provided in the present application can also increase the thickness of the non-bending area within a certain range while ensuring the bending performance, which is beneficial to a significant improvement in the impact resistance; in addition, the width setting of the bending zone and the transition zone based on the above-mentioned morphological design can improve the staggered bending performance, and while matching the bending performance of the folding device and maintaining as many effective impact-resistant areas as possible (ie, the non-bending area), it can achieve the effect of reducing the display light and shadow phenomena caused by the sharp change in thickness.

[0267] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0268]

[0269]

[0270]

[0271]

[0272]

Claims

1. An ultra-thin glass of unequal thickness, comprising a bending zone, a non-bending zone, and a buffer zone, wherein the buffer zones are symmetrically located on both sides of the bending zone, and the non-bending zones are located on the sides of the two buffer zones away from the bending zone; characterized in that: The thickness L2 of the non-bending area is 0.035-0.35 mm; Calculated in percentage by mass of oxides, it includes the following components: SiO2: 55.0-65.0%; Al2O3: 15.0-20.0%; Li2O: 0-2.5%; Na2O: 10-18.0%; K2O: 1-6%; MgO: 3-5.5%; CaO: 0-1%; Y2O3: 0-1%; ZrO2: 0.1-2.0%; B2O3: 0.1-3.0%; Among them, each component satisfies the following relationship: 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%; Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

2. The ultra-thin glass of unequal thickness according to claim 1, characterized in that: The fracture toughness of the unequal thickness ultra-thin glass is ≥0.76MPa·m 1 / 2 .

3. The ultra-thin glass of unequal thickness according to any one of claims 1 to 2, characterized in that: The Vickers hardness of the ultra-thin glass of unequal thickness is ≥573kgf / mm 2 .

4. The ultra-thin glass of unequal thickness according to any one of claims 1 to 3, characterized in that: When the thickness L2 of the non-bending zone of the ultra-thin glass of unequal thickness is 0.035 mm, the average pen impact height of the ultra-thin glass of unequal thickness is not less than 100 mm.

5. The ultra-thin glass of unequal thickness according to any one of claims 1 to 4, characterized in that: When the thickness L2 of the non-bending area of ​​the unequal thickness ultra-thin glass is 0.035 mm, the average coating pen impact height of the unequal thickness ultra-thin glass is not less than 170 mm.

6. The ultra-thin glass of unequal thickness according to any one of claims 1 to 5, characterized in that: The maximum thickness Hmax of the unequal thickness ultra-thin glass is 0.07-0.35 mm; wherein the ratio W of the thickness of the non-bending area to the maximum thickness Hmax is: W=L2 / Hmax is 0.5 or 1.

0.

7. The ultra-thin glass of unequal thickness according to claim 6, characterized in that: The width and depth of the buffer zone and the thickness of the bending zone of the unequal thickness ultra-thin glass satisfy the following formula: B=10×d / W+0.01×A×W, and B is 0.301-0.929; Among them, A is the aspect ratio of the buffer zone of the ultra-thin glass of unequal thickness, and its calculation formula is: ratio A=100×(c / a); wherein a is the width of the buffer zone; c is the depth of the buffer zone; d is the thickness of the bending zone.

8. The ultra-thin glass of unequal thickness according to claim 7, characterized in that: The value range of A is 0.022-2.

286.

9. The ultra-thin glass of unequal thickness according to claim 6, characterized in that: The ultimate bending radius R(2PB) of the ultra-thin glass of unequal thickness is 0.2-2.05 mm.

10. The ultra-thin glass of unequal thickness according to claim 6, characterized in that: When the thickness of the bending zone is 0.07 mm, the limit bending radius R(2PB) of the ultra-thin glass of unequal thickness is 1.75-2.05 mm; or When the thickness of the bending zone is 0.03 mm, the limit bending radius R(2PB) of the ultra-thin glass of unequal thickness is 0.20-0.55 mm.

11. The ultra-thin glass of unequal thickness according to any one of claims 1 to 10, characterized in that: The thickness and width of the buffer zone and the bending zone of the unequal thickness ultra-thin glass satisfy the following formula: C = b + 0.1 / A, where C is 7.044-29.

500. Among them, A is the aspect ratio of the buffer zone of the ultra-thin glass of unequal thickness, and its calculation formula is: ratio A=100*(c / a); among them, a is the width of the buffer zone; c is the depth of the buffer zone; b is the width of the bending zone.

12. The ultra-thin glass of unequal thickness according to any one of claims 1 to 11, characterized in that: The bending distance of ultra-thin glass of different thicknesses is 3-13mm.

13. The ultra-thin glass of unequal thickness according to claim 11, characterized in that: The bending life of ultra-thin glass products of varying thickness is: R0.8-R2.5>200,000 times.

14. The ultra-thin glass of unequal thickness according to any one of claims 1 to 13, characterized in that: The ultra-thin glass of unequal thickness does not contain SnO2.

15. The ultra-thin glass of unequal thickness according to any one of claims 1 to 14, characterized in that: When the ultra-thin glass of unequal thickness is 0.03-0.35 mm in thickness, the light transmittance at 550 nm is ≥91.0%.

16. The ultra-thin glass of unequal thickness according to any one of claims 1 to 15, characterized in that: The width a of the buffer zone is 14-45 mm, and the width b of the bending zone is 7-25 mm. The depth c of the buffer zone is 0.02-0.32 mm, and the thickness d of the bending zone is 0.015-0.1 mm.

17. The ultra-thin glass of unequal thickness according to any one of claims 1 to 16, characterized in that: The CS of the ultra-thin glass of unequal thickness is not less than 500 MPa.

18. The method for preparing ultra-thin glass of unequal thickness according to any one of claims 1 to 17, characterized in that: The following steps are involved: Step 1: Providing ultra-thin base glass; Step 2: chemically etching the ultra-thin base glass provided in step 1 to obtain ultra-thin glasses of varying thicknesses; Step 3: Chemically strengthen the ultra-thin glass of unequal thickness provided in step 2 to obtain strengthened ultra-thin glass of unequal thickness.

19. The method for preparing ultra-thin glass of unequal thickness according to claim 18, characterized in that: The chemical etching comprises chemically etching the fixed area of ​​the ultra-thin base glass using a first etching solution, wherein the chemical etching method is selected from top-spray chemical etching or immersion chemical etching; Furthermore, the method of chemically etching the fixed area of ​​the ultra-thin base glass is selected from any one of a mask method, a mold method or a directional guide method; Furthermore, the masking method is selected from a yellow light masking method and a coating method; Furthermore, the mold method is selected from the arc mold fixed etching method; Furthermore, the directional flow guiding method is selected from the precision liquid flow guiding etching method and the forward and reverse pulling method; and / or The first etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride; and / or The etching temperature in chemical etching is 20°C to 50°C, and / or The etching rate in chemical etching is 0.1 μm / min to 20 μm / min.

20. The method for preparing ultra-thin glass of unequal thickness according to claim 18, characterized in that: The chemical strengthening includes a first chemical strengthening step and a second chemical strengthening step; The first chemical strengthening process includes one or more chemical strengthening treatments, the temperature of the molten salt bath used in the chemical strengthening treatment is 380° C. to 550° C., the chemical strengthening time is 5 min to 240 min, and the molten salt used in the molten salt bath includes 0-50 wt% sodium salt, 40-100 wt% potassium salt, and 0-10 wt% lithium salt; further, the lithium salt is one or more of lithium nitrate and lithium sulfate; further, the sodium salt is one or more of sodium nitrate, sodium sulfate, and sodium carbonate; further, the potassium salt is one or more of potassium nitrate, potassium sulfate, and potassium carbonate; and / or The second chemical strengthening process includes placing the ultra-thin glass product of unequal thickness after the first chemical strengthening process in a third etching solution for 60s to 1200s to obtain ultra-thin glass of unequal thickness; wherein the third etching solution is one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride.

21. The method for preparing ultra-thin glass of unequal thickness according to claim 18, characterized in that: An edge processing step is also included between the chemical etching step and the chemical strengthening step; The edge processing step includes using a second etching solution to perform edge processing on the glass products of varying thickness that have undergone the chemical etching step; The second etching solution is selected from one or more of hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid, and ammonium fluoride; Furthermore, the glass product of unequal thickness after the chemical etching process includes a first surface and a second surface formed in the width and length directions, and the first surface and the second surface are coated with a strong acid-resistant ink before the edge processing process is performed; Furthermore, after the edge treatment process and before the chemical strengthening process, a strong acid-resistant ink removal process is also included; the strong acid-resistant ink removal process includes using an alkaline solution to remove the strong acid-resistant ink from the glass products of varying thickness that have undergone the edge treatment process; further, the alkaline solution is selected from NaOH, NaHCO3, Na2CO3, C6H 11 NaO7、C6H 15 One or more types of NO3; Furthermore, in the edge processing step, the etching temperature of the second etching solution for treating the glass products of unequal thickness is 20° C. to 50° C., the etching rate is 0.1 μm / min to 10 μm / min, and the etching time is 1 min to 10 min.

22. An ultra-thin base glass, characterized in that: The ultra-thin base glass has a thickness of 0.03-0.55 mm and comprises the following components in terms of oxide mass percentage: SiO2: 55.0-65.0%; Al2O3: 15.0-20.0%; Li2O: 0-2.5%; Na2O: 10-18.0%; K2O: 1-6%; MgO: 3-5.5%; CaO: 0-1%; Y2O3: 0-1%; ZrO2: 0.1-2.0%; B2O3: 0.1-3.0%; Among them, each component satisfies the following relationship: 52.0%≤(Al2O3+Na2O+K2O+MgO) / (B2O3+SiO2)≤68%; Wherein, the ultra-thin glass of unequal thickness does not contain ZnO, P2O5 and SrO.

23. The ultra-thin base glass according to claim 22, characterized in that: The ultra-thin base glass does not contain SnO2.

24. The ultra-thin base glass according to claim 22, characterized in that: The ultra-thin basic glass has a total thickness deviation TTV of ≤5 μm when the length and width are 200 mm*200 mm.

25. The ultra-thin base glass according to claim 22, characterized in that: The ultra-thin base glass is formed in one step using raw materials through a down-draw method; further, the melting temperature of the raw materials is 1350°C-1700°C, the melting time is 4h-240h, the annealing temperature is 550°C-650°C, and the annealing time is 0.5min-2000min.

26. Use of the ultra-thin glass of unequal thickness as claimed in any one of claims 1 to 17 or the ultra-thin glass of unequal thickness prepared by the method for preparing ultra-thin glass of unequal thickness as claimed in any one of claims 18 to 21 in automobile displays or windows, foldable electronic devices, aerospace window glass, aviation radiation-resistant glass, advertising display screens, building curtain walls, and furniture decoration.

27. A foldable electronic device, characterized in that: The invention relates to ultra-thin glass of unequal thicknesses prepared by the method for preparing ultra-thin glass of unequal thicknesses according to any one of claims 1 to 17 or any one of claims 18 to 21.

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