Unequal-thickness ultrathin glass and preparation method thereof

Abstract

The invention provides unequal-thickness ultrathin glass and a preparation method thereof. The preparation method comprises the following steps: (1) pasting a mask on the surface of UTG glass to obtain film-pasted glass; (2) firstly punching a row of laser holes at the center line of the bending area of the film-coated glass by using laser, recording the laser holes as a first row of laser holes, and then coating the bending area with fluoride as a coating material; then laser drilling is symmetrically conducted on the left side and the right side of the first row of laser holes in the direction from the center line of the bending area to the two sides, coating treatment is repeated once every time symmetric laser drilling is completed till the bending area is full of the laser holes, and the coated glass is obtained; (3) carrying out indirect acid etching on the bending area on the front surface of the coated glass by adopting hydrochloric acid to form an arc-shaped thinned surface so as to obtain roughly etched glass; and (4) carrying out polishing treatment on the rough etching glass to obtain the unequal-thickness ultra-thin glass. The method provided by the invention can significantly improve the flexibility and bending characteristics of the unequal-thickness ultrathin glass.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible materials, and particularly to an ultra-thin glass with unequal thicknesses and a preparation method thereof. Background Art

[0002] With the launch of folding mobile phones by manufacturers such as Huawei and Samsung, folding mobile phones have attracted more and more attention. Among them, the substrate and encapsulation material of the flexible display screen are key components of the folding mobile phone and are made of flexible materials.

[0003] The transparent polyimide material CPI (Colorless Polyimide) is the first-generation flexible material, which has excellent toughness and can be bent or even wound significantly. It has obvious advantages in terms of bending performance, impact resistance, mass production, cost, size coverage ability, etc., and can be mass-produced. Its market application has been quite mature. However, the transparency and hardness of CPI are relatively low, and it is easy to produce wrinkles and scratches, and the plastic feeling is too obvious, showing deficiencies in terms of shaping, hardness, surface flatness, and optical properties.

[0004] Ultra-thin glass UTG (Ultra-Thin Glass) is the second-generation flexible material, which has high transparency and hardness. However, it is difficult to combine the flexibility and hardness of UTG. This is because, in order for the UTG glass to have a good bending effect, its thickness must be reduced to about 30 μm, and the reduction of the thickness will lead to a decrease in hardness and strength. Moreover, UTG is an ultra-thin glass with equal thicknesses, that is, the thickness of the bending area and the non-bending area is the same. During the bending process, stress concentration is likely to occur, and after the number of bending times reaches a certain level, creases are likely to appear.

[0005] In order to overcome the deficiencies of UTG, on the basis of the UTG material, people have developed the third-generation flexible material, that is, ultra-flexible glass UFG (Ultra Flexible Glass). The thicknesses of the bending area and the non-bending area of UFG are inconsistent, which can weaken the stress concentration phenomenon caused by bending. Therefore, the crease problem can be solved.

[0006] During the production process of UFG, selective chemical thinning needs to be carried out on the bending area, and the thinning thickness of the bending area needs to be controlled so that the thickness change of the thinning surface (that is, the etching surface of the bending area) presents an arc shape, rather than a sudden change. This is because, when the thinning surface with a sudden thickness change is bent, very large local stress will be generated, resulting in a decrease in the bending performance. However, it is very difficult to make the etching surface of the bending area present a certain arc shape.

[0007] Therefore, there is an urgent need to provide an ultra-thin glass with unequal thicknesses whose thinning surface in the bending area presents an arc shape and a preparation method thereof. Summary of the Invention

[0008] In order to solve the problem that it is difficult for the bending and thinning surface of unequal-thickness ultra-thin glass in the prior art to present an arc change, the present invention provides an unequal-thickness ultra-thin glass and a preparation method thereof.

[0009] To solve the above technical problems, a first aspect of the present invention provides a preparation method of an unequal-thickness ultra-thin glass, wherein the method comprises the following steps:

[0010] (1) Stick a mask on the surface of the UTG glass to obtain a film-attached glass; wherein, the mask does not react with acid and can be penetrated by laser.

[0011] (2) First, use a laser to drill a row of laser holes at the center line of the bending area of the film-attached glass, denoted as the first row of laser holes, and then coat the bending area with a fluoride as a coating material.

[0012] After that, along the direction from the center line of the bending area to both sides, symmetrically perform laser drilling on the left and right sides of the first row of laser holes. Each time symmetric laser drilling is completed, repeat the coating process until the bending area is filled with laser holes to obtain a coated glass.

[0013] (3) First, indirectly acid-etch the bending area on the front surface of the coated glass with hydrochloric acid to form an arc-shaped thinning surface to obtain a roughly etched glass; then, optionally, directly acid-etch the back surface of the roughly etched glass with a hydrogen fluoride solution to obtain a finely etched glass.

[0014] (4) Polish the roughly etched glass or the finely etched glass to obtain an unequal-thickness ultra-thin glass.

[0015] A second aspect of the present invention provides an unequal-thickness ultra-thin glass, wherein the unequal-thickness ultra-thin glass includes a non-bending area and a bending area, and the thinning surface of the bending area presents an arc shape, and the arc curvature is 1×10 -4 -5×10 -2 m -1 , preferably 1×10 -3 -1×10 -2 m -1 ; the thickness at the center line of the bending area is 20-40 μm, preferably 25-35 μm.

[0016] Through the above technical solutions, the technical solutions provided by the present invention have the following beneficial technical effects:

[0017] The preparation method of the unequal-thickness ultra-thin glass provided in the present invention first forms fluoride coatings with different thicknesses in the bending area by means of masking, laser drilling and coating treatment, and then makes the fluoride coatings contact with concentrated hydrochloric acid to generate HF with different concentrations, so as to control the etching degree of different etching areas in the bending area, realize the continuous reduction change of the etching thickness, and make the thinning surface formed in the bending area present an arc with a certain curvature, thus significantly improving the flexibility and bending characteristics of the unequal-thickness ultra-thin glass. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a distribution diagram of laser holes in an implementation manner disclosed in an embodiment of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the thinning surface of the bending area of an unequal-thickness ultra-thin glass disclosed in an embodiment of the present invention.

[0021] Description of the Reference Numerals:

[0022] 1. The first column of laser holes; 2. The second column of laser holes; 3. The third column of laser holes; n. The nth column of laser holes. Detailed Embodiments

[0023] The following further describes in detail the embodiments of the present invention in conjunction with the drawings. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present application. The present invention can be implemented in many different forms, not limited to the specific embodiments disclosed in the text, but including all technical solutions falling within the scope of the claims.

[0024] These embodiments of the present invention are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of the components and steps, the components of the materials, the numerical expressions and numerical values described in these embodiments should be construed as merely exemplary, rather than as limitations.

[0025] The first aspect of the present invention provides a preparation method of an unequal-thickness ultra-thin glass, wherein the method includes the following steps:

[0026] (1) Attach a mask to the surface of the UTG glass to obtain a film-attached glass; wherein, the mask does not react with acid and can be penetrated by laser.

[0027] (2) First, use a laser to drill a row of laser holes at the center line of the bending area of the film-attached glass, denoted as the first row of laser holes, and then coat the bending area with a fluoride as the coating material.

[0028] Then, along the direction from the center line of the bending area to both sides, symmetrically perform laser drilling on the left and right sides of the first row of laser holes. After each completion of the symmetric laser drilling, repeat the coating process until the bending area is filled with laser holes to obtain a coated glass.

[0029] (3) First, indirectly acid-etch the bending area on the front side of the coated glass with hydrochloric acid to form an arc-shaped thinning surface to obtain a roughly etched glass; then, optionally, directly acid-etch the back side of the roughly etched glass with a hydrogen fluoride solution to obtain a finely etched glass.

[0030] (4) Polish the roughly etched glass or the finely etched glass to obtain an unequal-thickness ultra-thin glass.

[0031] In step (1):

[0032] In some embodiments, the material of the mask is a polymer; wherein, the polymer is selected from one or more of a polyimide film, a polyester film, and a nitrocellulose resin film.

[0033] Wherein, in the present invention, the mask does not chemically react with the acids commonly used in the technical field of glass chemical thinning and can be penetrated under laser irradiation. The polyester film refers to a polymer film containing an ester group.

[0034] In some embodiments, the present invention does not make special limitations on the UTG glass, and conventional UTG glasses in the art can be used in the present invention. For example, by mass percentage, the composition of the UTG glass may include: SiO2: 55%-70%, Al2O3: 15%-20%, B2O3: 0%-5%, Na2O: 10%-16%, K2O: 0%-5%, MgO: 1%-6%, CaO: 0%-5%, SnO: 0%-5%, BaO: 0%-5%.

[0035] Wherein, in the present invention, the UTG glass can be a commercially available product or can be prepared by a one-time forming method such as the float method, the overflow down-draw method, or the slot down-draw method well-known in the art.

[0036] In some embodiments, the thickness of the UTG glass is 0.05 - 0.16 mm, for example, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, and any number between these values, preferably 0.1 - 0.14 mm.

[0037] In some embodiments, the width of the bending region (i.e., the etching region, located in the middle region of the UTG glass) of the UTG glass is 5 - 40 mm, for example, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, and any number between these values, preferably 10 - 30 mm.

[0038] In some embodiments, a mask is attached to both surfaces of the UTG glass to obtain a film - attached glass.

[0039] In step (2):

[0040] In some embodiments, the operating conditions for laser drilling include: the pulse energy is 20 - 60 μJ, preferably 30 - 50 μJ; the pulse width is 5 - 35 ns, preferably 10 - 30 ns; the repetition frequency is 10 - 60 kHz, preferably 20 - 50 kHz.

[0041] In some embodiments, the aperture D of the laser hole is 100 - 400 μm, preferably 200 - 300 μm; along the center - line direction of the bending region, the distance between the centers of adjacent laser holes is D+(30 - 60) μm, preferably D+(40 - 50) μm; along the direction perpendicular to the center - line of the bending region, the distance between the centers of adjacent laser holes is D+(30 - 60) μm, preferably D+(40 - 50) μm. Herein, in the present invention, taking D+(30 - 60) μm as an example, D+(30 - 60) μm represents the range between (D + 30) μm and (D + 60) μm.

[0042] In some embodiments, the fluoride is selected from water - insoluble fluorides, preferably selected from one or more of calcium fluoride, magnesium fluoride, and aluminum fluoride, and more preferably calcium fluoride.

[0043] In some embodiments, the coating treatment is selected from one or more of PVD physical vapor deposition method, CVD chemical vapor deposition method, and vacuum evaporation coating method, preferably the vacuum evaporation coating method. Herein, in the present invention, through the coating treatment, a fluoride coating, such as a calcium fluoride coating, can be formed on the film - attached glass.

[0044] In some embodiments, the operating conditions of the vacuum evaporation coating method include: the vacuum degree is pumped to be lower than 3.0×10 -3 Pa; the temperature of the vacuum chamber is heated to 80 - 350 °C, preferably 100 - 300 °C; the rotation speed of the work turntable is 5 - 40 r / min, preferably 10 - 30 r / min; the coating treatment time is 1 - 3 min, preferably 1.5 - 2.5 min.

[0045] Among them, in the present invention, the laser holes that are symmetric about the center line of the bending area are regarded as the same column of laser holes, and the distribution of the laser holes is as Figure 1 shown. In Figure 1 , along the direction from the center line of the bending area to both sides, 1 represents the first column of laser holes, 2 represents the second column of laser holes, 3 represents the third column of laser holes, and so on, n represents the nth column of laser holes. The coating treatment performed after drilling the first column of laser holes is the first coating treatment, the coating treatment performed after drilling the second column of laser holes is the second coating treatment, the coating treatment performed after drilling the third column of laser holes is the third coating treatment, and so on. The coating treatment performed after drilling the nth column of laser holes is the nth coating treatment. Among them, the first column of laser holes has undergone n coating treatments in total, the second column of laser holes has undergone n - 1 coating treatments in total, the third column of laser holes has undergone n - 2 coating treatments in total, and so on. The nth column of laser holes has undergone n - (n - 1) coating treatments in total. By pasting the mask and controlling the operation sequence of laser drilling and coating treatment, fluoride coatings with different thicknesses can be produced in the bending area, so that the thickness of the fluoride coating symmetrically decreases sequentially along the direction from the center line to both sides, so that after the acid etching treatment, an arc curvature controlled at 1×10 -4 -5×10 -2 m -1 , preferably 1×10 -3 -1× -2 m -1 can be obtained. Among them, the arc-shaped thinning surface is as Figure 2 shown.

[0046] In step (3):

[0047] In some embodiments, the indirect acid etching is acid mist etching, and the operating conditions of the acid mist etching include: the hydrochloric acid is concentrated hydrochloric acid; the concentration of the acid mist (that is, the mass of the droplets distributed in each cubic meter of air) is 200 - 300 mg / m 3 , preferably 240 - 280 mg / m 3 ; the droplet diameter of the acid mist is 0.5 - 2 μm, preferably 0.8 - 1.2 μm; the treatment temperature of the acid mist is 60 - 90 °C, preferably 65 - 75 °C; the treatment time is 2 - 4 h, preferably 2.5 - 3.5 h.

[0048] Among them, in the present invention, the mass concentration of concentrated hydrochloric acid is a conventional concentration in the art. For example, it is 35-38%. The front side of the coated glass in step (3) refers to the side coated with the fluoride coating. Taking the calcium fluoride coating as an example, the chemical reaction equation occurring during the acid mist etching process is: CaF2 + 4HCl → 2HF + CaCl2. The HF generated by the reaction will etch the glass surface. The greater the thickness of the calcium fluoride coating, the more HF is correspondingly generated, and the greater the etching degree of the glass. In the direction from the center line of the bending area to both sides, the thickness of the calcium fluoride coating gradually decreases, and the etching depth decreases in turn. Therefore, a smooth arc-shaped thinning surface can be formed on the etched surface of the bending area.

[0049] In some embodiments, first, hydrochloric acid is used to indirectly acid-etch the bending area on the front side of the coated glass to form an arc-shaped thinning surface, obtaining a roughly etched glass; then, a hydrofluoric acid solution is used to directly acid-etch the back side of the roughly etched glass to obtain a precisely etched glass.

[0050] Among them, in the present invention, whether to perform direct acid etching can be judged according to the thickness of the UTG glass. When the thickness of the UTG glass is greater than or equal to 0.1 mm, it is preferably to first perform indirect acid etching and then use direct acid etching for thinning treatment. When the thickness of the UTG glass is less than 0.1 mm, the direct acid etching operation can be omitted by optimizing the operating conditions of the indirect acid etching.

[0051] In some embodiments, the direct acid etching is immersion acid etching, and the operation of the immersion acid etching includes: first removing the mask on the roughly etched glass, and then reattaching a mask on the front side of the roughly etched glass; then placing it in a hydrofluoric acid solution to acid-etch the back side of the roughly etched glass to obtain a precisely etched glass.

[0052] In some embodiments, the mass concentration of the hydrofluoric acid solution is 25%-35%, preferably 28-32%; the treatment temperature is 30-50°C, preferably 35-45°C; the etching time is 2-4 min, preferably 2.5-3.5 min.

[0053] In some embodiments, the thickness at the center line of the bending area of the precisely etched glass is 20-40 μm, preferably 25-35 μm.

[0054] Among them, in the present invention, after one direct acid etching is completed, it is rinsed with clean water, and then the thickness at the center line of the bending area (i.e., the thinnest part of the bending area) is measured. If the thickness is greater than the above-defined range, multiple direct acid etching operations can be repeated until the thickness at the center line of the bending area is 20-40 μm, preferably 25-35 μm.

[0055] In some embodiments, the present invention does not impose special restrictions on polishing, and the polishing operation can be carried out according to the well-known methods in the art. Among them, in the present invention, after polishing treatment, the surface roughness (including flat surface and arc surface) of the glass is < 0.01 μm.

[0056] In some embodiments, it is preferable to perform strengthening treatment on the polished glass. Among them, the strengthening treatment includes: placing the polished glass in pure potassium salt, keeping it at 300 - 500 °C for 5 - 10 min, and then performing cleaning to obtain an unequal-thickness ultra-thin glass.

[0057] The second aspect of the present invention provides an unequal-thickness ultra-thin glass. Among them, the unequal-thickness ultra-thin glass includes a non-bending area and a bending area. The thinning surface of the bending area presents an arc shape, and the arc curvature is 1×10 -4 -5×10 -2 m -1 , preferably 1×10 -3 -1×10 -2 m -1 ; the thickness at the center line of the bending area is 20 - 40 μm, preferably 25 - 35 μm.

[0058] For the unequal-thickness ultra-thin glass in the present invention, the thinning surface is a smooth arc, so it has excellent bending performance.

[0059] In some embodiments, the unequal-thickness ultra-thin glass provided by the present invention is prepared by the method described in the first aspect of the present invention.

[0060] The present invention will be described in detail below through examples.

[0061] Example 1

[0062] (1) Stick polyimide films on both surfaces of UTG glass (formed by one-time drawing, with dimensions of 160 mm × 160 mm × 0.14 mm, and the width of the bending area is 20 mm) to obtain film-attached glass;

[0063] (2) First, use pulsed laser (pulse energy is 40 μJ, pulse width is 20 ns, and repetition frequency is 40 kHz) to punch the first row of laser holes on the center line of the bending area of the film-attached glass; among them, the aperture D of the laser holes is 300 μm, and along the center line direction of the bending area, the distance between the centers of adjacent laser holes is 350 μm;

[0064] Then, using calcium fluoride as the coating material, under the conditions of a vacuum degree lower than 3.0×10 -3 Pa, the temperature of the vacuum chamber is 300 °C, the rotation speed of the turntable is 20 r / min, and the coating time is 2 min, perform vacuum evaporation coating treatment on the bending area;

[0065] Subsequently, laser drilling is symmetrically performed on both the left and right sides of the laser holes in the first column to form the second column of laser holes. Among them, along the center line direction of the vertical bending area, the distance between the centers of adjacent laser holes is 350 μm. After the second column of laser holes is drilled, the bending area is repeatedly coated.

[0066] Laser drilling is symmetrically performed on both the left and right sides of the second column of laser holes to form the third column of laser holes. After the third column of laser holes is drilled, the bending area is repeatedly coated.

[0067] Continue to repeat laser drilling and coating until the bending area is filled with laser holes to obtain coated glass.

[0068] (3) Place the above-mentioned coated glass into the acid mist treatment chamber, place it flat with the front side (coated surface) facing up, and perform acid mist etching with concentrated hydrochloric acid to form an arc-shaped thinning surface to obtain roughly etched glass. Among them, the mass concentration of concentrated hydrochloric acid is 37%, the mass of the acid mist is 260 mg / m 3 , the particle size of the acid mist droplets is 1 μm, the temperature in the treatment chamber is 70 °C, and the treatment time is 3 h.

[0069] After the acid mist etching is completed, wash the above-mentioned roughly etched glass with pure water to remove the polyimide films attached to both surfaces, and then reattach a layer of polyimide film to the front side of the roughly etched glass. Then place it in a hydrofluoric acid solution with a mass concentration of 30% and perform immersion acid etching on the back side of the roughly etched glass. Among them, the temperature of the hydrofluoric acid solution is 40 °C, and the etching time is 3 min.

[0070] After the immersion acid etching is completed, rinse it with pure water and measure the thickness at the center line of the bending area to be 50 μm. Repeat the above immersion acid treatment until the thickness at the center line of the bending area is 30 μm.

[0071] (4) Polish the finely etched glass to control the roughness of each glass plane and arc surface to be <0.01 μm, then place the polished glass into pure potassium salt, keep it at 400 °C for 8 min for strengthening treatment, and then take it out and wash it with clean water to obtain unequal-thickness ultra-thin glass.

[0072] Example 2

[0073] Same as Example 1, the differences are as follows:

[0074] In step (2), the coating material is magnesium fluoride; the aperture D of the laser holes is 200 μm. Along the center line direction of the bending area, the distance between the centers of adjacent laser holes is 250 μm, and along the direction perpendicular to the center line of the bending area, the distance between the centers of adjacent laser holes is 250 μm.

[0075] In step (3), the thickness at the center line of the bending area is 35 μm.

[0076] Example 3

[0077] Same as Example 1, except that:

[0078] In step (2), the coating material is aluminum fluoride; the aperture D of the laser holes is 250 μm, and along the center line direction of the bending area, the distance between the centers of adjacent laser holes is 290 μm, and along the direction perpendicular to the center line of the bending area, the distance between the centers of adjacent laser holes is 290 μm;

[0079] In step (3), the thickness at the center line of the bending area is 25 μm.

[0080] Example 4

[0081] (1) Stick the polyimide film on two surfaces of the UTG glass (formed by one-time drawing, with dimensions of 160 mm × 160 mm × 0.07 mm, and the width of the bending area is 20 mm) to obtain the film-attached glass;

[0082] (2) First, use pulsed laser (pulse energy is 40 μJ, pulse width is 20 ns, and repetition frequency is 40 kHz) to punch the first row of laser holes on the center line of the bending area of the film-attached glass; among them, the aperture D of the laser holes is 300 μm, and along the center line direction of the bending area, the distance between the centers of adjacent laser holes is 350 μm;

[0083] Then, use calcium fluoride as the coating material, and under the conditions of a vacuum degree lower than 3.0×10 -3 Pa, the temperature of the vacuum chamber is 300 °C, the rotation speed of the turntable is 20 r / min, and the coating time is 2 min, perform vacuum evaporation coating treatment on the bending area;

[0084] After that, perform laser drilling symmetrically on the left and right sides of the first row of laser holes to punch the second row of laser holes; among them, along the direction perpendicular to the center line of the bending area, the distance between the centers of adjacent laser holes is 350 μm; after punching the second row of laser holes, repeat the coating treatment on the bending area;

[0085] Perform laser drilling symmetrically on the left and right sides of the second row of laser holes to punch the third row of laser holes, and after punching the third row of laser holes, repeat the coating treatment on the bending area;

[0086] Continue to repeat the laser drilling and coating treatment until the bending area is filled with laser holes to obtain the coated glass;

[0087] (3) Place the above-mentioned coated glass in the acid mist treatment chamber, place it flat with the front side (coated surface) facing up, and perform acid mist etching with concentrated hydrochloric acid to form an arc-shaped thinning surface to obtain the roughly etched glass; among them, the mass concentration of the concentrated hydrochloric acid is 37%, and the mass of the acid mist is 260 mg / m 3, the acid mist droplet size is 1 μm, the temperature in the treatment chamber is 70 °C, and the treatment time is 3 h; after the acid mist etching is completed, it is rinsed clean with pure water, and the thickness at the center line of the bending area is measured to be 35 μm;

[0088] (4) Polish the precision-etched glass, control the roughness of each glass plane and arc surface to be <0.01 μm, then place the polished glass into pure potassium salt, keep it at 400 °C for 8 min for strengthening treatment, and then take it out and wash it with clean water to obtain ultra-thin glass with unequal thickness.

[0089] Test Example 1

[0090] Use a 2.5D image measuring instrument (model: DBM-322C, manufacturer: Dongguan Kemanli Precision Optics Measurement Technology Co., Ltd., magnification factor: 3 times) to measure the arc curvature of the arc-shaped thinning surface of the ultra-thin glass with unequal thickness prepared in Examples 1-4. The results are shown in Table 1.

[0091] Table 1

[0092] <![CDATA[Arc curvature (m -1 )]]> Thickness (μm) at the center line of the bending area Example 1 <![CDATA[1.45×10 -3 > 30 Example 2 <![CDATA[5.1×10 -3 > 35 Example 3 <![CDATA[3.28×10 -3 > 25 Example 4 <![CDATA[8.15×10 -3 > 35

[0093] Test Example 2

[0094] According to the national standard "Flexible Glass Bending Fatigue Test Method" (GB / T 44752-2024), conduct bending tests on the same batch of UTG glass used in Example 1 and the ultra-thin glass with unequal thickness prepared in Examples 1-4, and then record the number of bending times when obvious bending marks appear. The results are shown in Table 2.

[0095] Table 2

[0096]

[0097]

[0098] As can be seen from Table 2, obvious bending marks appear on the UTG glass after 210,000 bending times. However, after treating the UTG glass by the method of the present invention, the ultra-thin glass with unequal thickness prepared in Examples 1-3 does not show obvious bending marks until at least 410,000 bending times. This shows that the ultra-thin glass with unequal thickness prepared in the present invention has excellent bending performance.

[0099] Test Example 3

[0100] Use the same batch of UTG glass, prepare 20 samples according to the method in Example 1, and then repeat the bending test with reference to Test Example 2. The results are shown in Table 3.

[0101] Table 3

[0102]

[0103]

[0104] As can be seen from Table 3, the preparation method provided in the present invention has stable effects and good repeatability, and is suitable for industrial promotion.

[0105] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified or partial technical features can be equivalently replaced without departing from the scope and spirit of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.

Claims

1. A method for preparing ultra-thin glass with unequal thicknesses, characterized in that, The method includes the following steps: (1) Attach a mask to the surface of the UTG glass to obtain a film-attached glass; wherein, the mask does not react with acid and can be penetrated by laser; (2) First, use a laser to drill a row of laser holes at the center line of the bending area of the film-attached glass, denoted as the first row of laser holes, and then coat the bending area with a fluoride as the coating material; After that, along the direction from the center line of the bending area to both sides, symmetrically perform laser drilling on the left and right sides of the first row of laser holes. Each time after the symmetric laser drilling is completed, repeat the coating process until the bending area is filled with laser holes to obtain a coated glass; (3) First, indirectly acid-etch the bending area on the front surface of the coated glass with hydrochloric acid to form an arc-shaped thinning surface to obtain a roughly etched glass; then optionally, directly acid-etch the back surface of the roughly etched glass with a hydrogen fluoride solution to obtain a finely etched glass; (4) Polish the roughly etched glass or the finely etched glass to obtain an unequal-thickness ultra-thin glass.

2. The preparation method according to claim 1, characterized in that, The material of the mask is a polymer; Preferably, the polymer is selected from one or more of a polyimide film, a polyester film, and a nitrocellulose resin film.

3. The preparation method according to claim 1 or 2, characterized in that, The thickness of the UTG glass is 0.05 - 0.16 mm, preferably 0.1 - 0.14 mm; Preferably, the width of the bending area of the UTG glass is 5 - 40 mm, preferably 10 - 30 mm.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The operating conditions for laser drilling include: the pulse energy is 20 - 60 μJ, preferably 30 - 50 μJ; the pulse width is 5 - 35 ns, preferably 10 - 30 ns; the repetition frequency is 10 - 60 kHz, preferably 20 - 50 kHz; Preferably, the aperture D of the laser hole is 100 - 400 μm, preferably 200 - 300 μm; along the center line direction of the bending area, the distance between the centers of adjacent laser holes is D+(30 - 60) μm, preferably D+(40 - 50) μm; along the direction perpendicular to the center line of the bending area, the distance between the centers of adjacent laser holes is D+(30 - 60) μm, preferably D+(40 - 50) μm.

5. The preparation method according to any one of claims 1-4, characterized in that, The fluoride is selected from water-insoluble fluorides, preferably selected from one or more of calcium fluoride, magnesium fluoride, and aluminum fluoride, and further preferably calcium fluoride; Preferably, the coating process is selected from one or more of PVD physical vapor deposition method, CVD chemical vapor deposition method, and vacuum evaporation coating method, and preferably the vacuum evaporation coating method.

6. The preparation method according to claim 5, characterized in that, The operating conditions of the vacuum evaporation coating method include: the vacuum degree is pumped down to less than 3.0×10 -3 Pa; the temperature of the vacuum chamber is heated to 80 - 350 °C, preferably 100 - 300 °C; the rotation speed of the turntable is 5 - 40 r / min, preferably 10 - 30 r / min; the coating treatment time is 1 - 3 min, preferably 1.5 - 2.5 min.

7. The preparation method according to any one of claims 1-6, characterized in that, The indirect acid etching is acid mist etching; Preferably, the operating conditions of the acid mist etching include: hydrochloric acid being concentrated hydrochloric acid; the density of the acid mist being 200-300 mg / m 3 , preferably 240-280 mg / m 3 ; the droplet size of the acid mist being 0.5-2 μm, preferably 0.8-1.2 μm; the treatment temperature of the acid mist being 60-90 °C, preferably 65-75 °C; and the treatment time being 2-4 h, preferably 2.5-3.5 h.

8. The preparation method according to any one of claims 1-7, characterized in that, First, indirectly acid-etch the bending area on the front surface of the coated glass with hydrochloric acid to form an arc-shaped thinning surface to obtain a roughly etched glass; then directly acid-etch the back surface of the roughly etched glass with a hydrogen fluoride solution to obtain a finely etched glass; Preferably, the direct acid etching is immersion acid etching; Preferably, the operation of the immersion acid treatment includes: first remove the mask on the roughly etched glass, and then reattach a mask on the front surface of the roughly etched glass; then place it in a hydrofluoric acid solution to acid-etch the back surface of the roughly etched glass to obtain a finely etched glass; Preferably, the mass concentration of the hydrofluoric acid solution is 25%-35%, preferably 28%-32%; the treatment temperature is 30-50°C, preferably 35-45°C; the etching time is 2-4 min, preferably 2.5-3.5 min; Preferably, the thickness at the center line of the etched area of the precision-etched glass is 20-40 μm, preferably 25-35 μm.

9. The preparation method according to any one of claims 1-8, characterized in that, The polished glass is subjected to a strengthening treatment; wherein, the strengthening treatment includes: placing the polished glass in pure potassium salt, keeping it at 300-500°C for 5-10 min, and then cleaning it to obtain an ultra-thin glass with unequal thicknesses.

10. An unequal-thickness ultra-thin glass, characterized in that, The unequal-thickness ultra-thin glass includes a non-bending area and a bending area, and the thinning surface of the bending area presents an arc shape, and the arc curvature is 1×10 -4 -5×10 -2 m -1 , preferably 1×10 -3 -1×10 -2 m -1 ; the thickness at the center line of the bending area is 20-40 μm, preferably 25-35 μm.

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