CN116040953A

CN116040953A - Flexible foldable glass and preparation method thereof

Info

Publication number: CN116040953A
Application number: CN202211326319.4A
Authority: CN
Inventors: 郑建军; 徐炯�; 杨夫舜; 岳伟; 齐彦杰; 曹志强; 李�杰
Original assignee: Wuhu Dongxin Photoelectric Technology Co ltd
Current assignee: Wuhu Dongxin Photoelectric Technology Co ltd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2023-05-02

Abstract

The invention discloses flexible foldable glass and a preparation method thereof, wherein the preparation method comprises the following steps: covering an acid-resistant protective film on the surface of the glass, and carrying out laser drilling treatment, chemical etching, tempering treatment and surface etching on a target folding area of the glass; the preparation method can realize industrialized mass production of the flexible foldable glass with the thickness of 100-500 mu m under the condition of not thinning the thickness of the glass, and the bending times of the prepared bent glass can reach more than 20w times under the condition of high shock resistance.

Description

Flexible foldable glass and preparation method thereof

Technical Field

The invention belongs to the technical field of flexible foldable glass, and particularly relates to flexible foldable glass and a preparation method thereof, and particularly relates to a preparation method of flexible foldable glass with the thickness of more than or equal to 100 mu m.

Background

With the rapid development of flexible display technology and the update of electronic products, flexible display products such as foldable, stretchable and crimpable products gradually enter the field of view of consumers. However, in the trend of the flexible display products toward lighter and thinner and portable display products, the requirements for the lighter and thinner outer cover plate are also raised. However, when the cover plate of the flexible display folded product is made of Ultra-Thin Glass (UTG) with the thickness thinned to be less than 100 μm, the Glass has the flexible folding capability, but the impact resistance of the Glass against the outside is poor due to the lower thickness of the Glass, so that the reliability and stability of the product are reduced.

The ultra-thin glass with the thickness less than or equal to 100 mu m prepared by adopting a down-draw method, an overflow method and a thinning method is easy to damage in transportation and processing without performance strengthening, so that the ultra-thin glass is blocked on the commercial road of the flexible folding cover plate because of low yield and high manufacturing cost. In addition, in the process of manufacturing the flexible folding cover plate by using the ultrathin glass, UTG with the thickness of 30 μm is usually selected as a first-choice material to ensure the extremely small folding effect, so that the extremely thin impact resistance of the ultrathin glass cannot meet the requirement of the conventional cover plate.

Disclosure of Invention

In order to solve the technical problems, the invention provides the flexible foldable glass and the preparation method thereof, and the preparation method can process the glass with the thickness of 100-500 mu m into the flexible foldable glass, so that the folding times of the prepared flexible foldable glass can reach more than 20w times under the condition of high shock resistance.

The technical scheme adopted by the invention is as follows:

a method of making a flexible foldable glass, the method comprising the steps of:

(1) Covering the surface of the glass with an acid-resistant protective film;

(2) Performing laser drilling treatment on a target folding region of the glass, so that the acid-resistant protective film in the hole region is removed after the drilling treatment, and etching is facilitated;

(3) Chemically etching the glass treated in the step (1) to etch away all the glass in the hole area;

(4) Removing the acid-resistant protective film;

(5) Tempering the glass treated in the step (4), and improving the strength of the glass;

(6) And (5) carrying out surface etching on the glass treated in the step (5).

In the step (1), the thickness of the glass is 100-500 mu m, and compared with the thickness of the glass which is 30-70 mu m, the glass with the thickness has higher strength, high impact resistance and excellent scratch resistance.

In the step (1), the acid-resistant protective film is a polyurethane UV (ultraviolet) mucous membrane-reducing film which can be made of HF (high-frequency) and HNO (high-frequency) materials ₃ The acid-proof film can not fall off after being sprayed for 200min under the HCL mixed acid.

In the step (1), the target folding area of the glass is more than one, so that the flexible foldable glass with different folding forms can be prepared. The width of the target folding area is 20-40mm.

In the step (2), during punching, the punched holes are distributed in the target folding area of the glass in an array arrangement mode, so that stress generated by the glass during folding can be effectively released, and the bending performance is improved.

Furthermore, the holes are distributed in the target folding area of the glass in a staggered mode in an array arrangement mode, so that stress generated by the glass during folding can be evenly and effectively released.

Further, the shape and the size of each hole are identical, so that the uniformity of the stress distribution of the glass in the folding area can be ensured.

The shape of each hole is a waist hole, and each waist hole is arranged perpendicular to the folding direction of the glass; the waist holes arranged in this way can make the strength of the glass in the folding area in the folding direction weaker than that in the non-folding direction, so that the glass can maintain higher strength of the glass in the folding area in the non-folding direction under the condition of ensuring good folding performance of the glass.

Further, the width of the waist hole is 50-300 μm, the aspect ratio is 10-100, the interval between the upper and lower holes is 100-300 μm, and the interval between the left and right holes is 100-3000 μm, preferably 300-500 μm.

In the step (2), the glass which is not subjected to strengthening treatment is fragile and fragile, the hole size of holes to be punched is small, the distance between the holes is extremely small, and the ultraviolet laser cutting machine is adopted to cut and punch the target folding area covered with the acid-proof film glass, so that the laser power is between 20 and 40w, and the wavelength is between 300 and 400nm, and the glass cannot be broken during punching.

In the step (3), during chemical etching treatment, the acid etching rate is controlled to be 1-2 mu m/min, an ultrasonic device is arranged in an etched groove body, the ultrasonic power in the acid etching process is 5-10w, and the etching is carried out until cutting waste in each hole falls off.

In the step (3), ultrasonic treatment is carried out during etching, and a chamfering process is adopted when the target plate thickness is half of the target plate thickness, so that the uniformity of the plate thickness of the glass is ensured, the uniformity of the etching acid liquid concentration and the uniform falling-off of the cutting waste in the etching process are ensured, and the accumulation of reactants after etching is effectively prevented.

In the step (3), the chemical etching uses the etching solution with the following composition by weight percent: 0.1 to 0.4 percent of hydrofluoric acid, 40 to 60 percent of sulfuric acid, 0.2 to 0.4 percent of phosphoric acid, 1 to 2 percent of ammonium sulfate, 1.0 to 20.0 percent of acetic acid, 2.0 to 10.0 percent of nitric acid and the balance of deionized water.

In the step (4), the acid-resistant protective film is removed by light stripping under the irradiation of 200-300mJ ultraviolet light.

In the step (5), the tempering treatment conditions are as follows: preheating for 30-60min at 370-400 ℃, and then tempering for 60-90min at 380-410 ℃ to control the stress value of the tempered glass in the non-folding zone to be 700-800MPa and the depth of the stress layer to be 12-16 mu m.

In the step (5), the tempering liquid used in the tempering treatment is potassium nitrate solution with the mass fraction of 99.99 percent.

In the step (6), the surface etching amount is controlled to be 4-8 mu m, the etching rate is controlled to be 0.5-0.8 mu m/min, and the surface roughness of the flexible foldable glass after the surface etching process is controlled to be 0.2-0.30 mu m.

In the step (6), the etching solution used for surface etching comprises the following components in percentage by weight: 0.1 to 0.4 percent of hydrofluoric acid, 40 to 60 percent of sulfuric acid, 0.2 to 0.4 percent of phosphoric acid, 1 to 2 percent of ammonium sulfate, 1.0 to 20.0 percent of acetic acid, 2.0 to 10.0 percent of nitric acid and the balance of deionized water.

Further, before or after the step (1), the method further comprises the step of cutting the glass into a shape required by a use scene by laser; the laser cutting adopts an infrared picosecond laser cutting machine, the laser power is between 5 and 10w, the wavelength is between 1000 and 1500nm, the picosecond laser cutting mode can effectively control the edge breakage of glass to be less than 10 mu m, the laser cutting machine has the processing capability on special-shaped glass, and meanwhile, the laser cutting is not limited by the material and the size of a sample, and the glass with smaller R angle can be cut.

Further, the steps (2), (3) and (4) are all followed by ultrasonic cleaning.

The invention also provides the flexible foldable glass prepared by the preparation method, and the folding times of the bent glass can reach more than 20w times under the condition of high shock resistance.

Compared with the prior art, the invention has the following advantages:

1. the preparation method provided by the invention can realize the preparation of the flexible foldable glass with the thickness of 100-500 mu m, has no limit on the external dimension, can be used as cover plate glass for various foldable display devices such as folding mobile phones, folding notebook computers and the like, and can effectively solve the CPI crease problem and the problem of low UTG strength by utilizing the rigidity of the glass;

2. according to the invention, the acid-proof film is covered on the surface of the glass, then, each hole pattern of a glass folding area is cut by using laser, etching waste in each hole is removed in a chemical etching mode, folding performance and impact strength of the glass are guaranteed by tempering treatment, and finally, surface microcracks are removed by surface etching to improve the strength of the glass, so that industrialized batch production of flexible foldable glass with the thickness of 100-500 mu m can be realized under the condition of not thinning the thickness of the glass, and the thickness of the glass can be thinned at will according to the use requirement in the later period;

3. the folding glass prepared by the preparation method provided by the invention can realize the inward bending and the outward bending of the glass at the same time, and does not limit the folding direction of the glass;

4. the preparation method provided by the invention can realize multi-form folding of the glass according to the folding requirement of the glass, and effectively solve the problems of crease marks replacing CPI materials and excessively low UTG strength;

5. the flexible foldable glass provided by the invention not only has high shock resistance, but also has higher process yield, lower production cost and more favorable commercialization because the thickness of the glass adopted in the processing process is more than or equal to 100 mu m.

Drawings

FIG. 1 is a schematic view of the spacing between the holes of a flexible foldable glass fold region in accordance with the present invention;

FIG. 2 is a fold area array hole pattern of the flexible foldable glass of the present invention.

Detailed Description

The present invention will be described in detail with reference to examples.

Examples

A method of making a flexible foldable glass comprising the steps of: covering an acid-proof protective film, carrying out laser hole digging, carrying out chemical etching, carrying out ultrasonic cleaning, removing the acid-proof protective film, carrying out chemical tempering and optimizing surface etching;

the original glass with the thickness of 100-500 mu m is cut into a shape required by a use scene by adopting a picosecond infrared laser cutting machine before or after the acid-proof protective film is covered, the laser power is 5-10w, the wavelength is 1000-1500nm, the edge collapse of the glass can be effectively controlled to be less than 10 mu m by adopting a picosecond laser cutting mode, the processing capability (including R angle) of special-shaped glass is realized, and meanwhile, the laser cutting is not limited by the material and the size of a sample.

Acid-resistant protective films are coated on both sides of the glass, and the acid-resistant protective films are polyurethane UV (ultraviolet) mucous membrane-reducing films which can be coated on HF (high frequency) and HNO (high frequency) surfaces ₃ The adhesive cannot fall off after being sprayed for 200min under HCl mixed acid.

The laser hole digging adopts an ultraviolet laser cutting machine to cut and dig holes. The ultraviolet cutting power is 20-40w, the wavelength is 300-400nm, and the holes dug out are distributed in the folding area of the glass in an array arrangement mode in a staggered mode, so that stress generated by the glass during folding can be evenly and effectively released.

The shape and the size of each hole are identical, so that the uniformity of the stress distribution of the glass in the folding area can be ensured.

The shape of each hole is a waist hole, and each waist hole is arranged perpendicular to the folding direction of the glass; the waist holes in the steps can enable the strength of the glass in the folding area in the folding direction to be weaker than that in the non-folding direction, so that the glass in the folding area can be kept high in the non-folding direction under the condition of good folding performance.

The length L of the waist hole is 4000-5000 μm, the hole width d is 50-300 μm, the vertical distance a between two holes is 100-300 μm, and the left-right distance b is 300-500 μm, as shown in figure 1.

The cut glass is subjected to ultrasonic cleaning so as to remove glass powder generated in the cutting process, and fluosilicic acid generated by the reaction of the glass powder remained in the next etching process and hydrofluoric acid is prevented, so that the fluosilicic acid is accumulated in pores to influence etching.

When chemical etching is performed, the area protected by the acid-resistant protective film is not etched into an unfolded area; the etched part is exposed part of laser drilling, and the pattern area and the cutting size are enlarged partially after the etching. The acid etching rate is 1-2 mu m/min, the ultrasonic power in the acid etching process is 5-10w, and the cutting waste in the pattern area is ensured to fall off uniformly. A chamfering process is adopted in the etching process, so that reactant accumulation after etching is effectively prevented. After the etching process is finished, all glass in the aperture of the sample punched in the folding area is peeled off, and the folding area forms waist holes distributed in a staggered array.

The chemical etching solution comprises the following components in percentage by weight: 0.1 to 0.4 percent of hydrofluoric acid, 40 to 60 percent of sulfuric acid, 0.2 to 0.4 percent of phosphoric acid, 1 to 2 percent of ammonium sulfate, 1.0 to 20.0 percent of acetic acid, 2.0 to 10.0 percent of nitric acid and the balance of deionized water.

Performing performance strengthening process treatment on the glass subjected to chemical etching, performing ultrasonic cleaning and baking and drying at 60-80 ℃, and performing chemical tempering on the flexible foldable glass, wherein the chemical tempering principle is as follows: sodium-potassium ion exchange process is carried out in the glass under the high temperature condition, and the extrusion effect generated by the volume difference of the sodium-potassium ion exchange process and the glass is utilized to improve the surface strength and the flexibility of the glass; chemical tempering process: heating the chemically etched glass in a preheating furnace at 370-400 deg.c for 30-60min, and after preheating, setting the glass inside a chemical toughening tank at 380-410 deg.c, with the toughening time set at 60-90min, the stress value range of the toughened glass being 700-800MPa and the stress layer depth being 12-16 microns.

The tempering liquid used in the tempering treatment is potassium nitrate solution with the mass fraction of 99.99 percent.

The surface etching treatment is carried out on the tempered glass, and the main purpose of the surface etching treatment is to repair the problems of microcracks generated in the processing process of the glass, defects amplified after the tempering process and the like; in the surface etching process, the surface etching amount of the flexible foldable glass is controlled to be 4-8 mu m, the etching rate is controlled to be 0.5-0.8 mu m/min, the surface roughness of the flexible foldable glass after the surface etching process is controlled to be 0.2-0.30 mu m, the surface strength of the glass is improved, finally, the finished product is cleaned and dried by ultrasonic cleaning, and the appearance of the array holes of the folding region of the finished product is shown in figure 2.

The etching solution used for the surface etching comprises the following components in percentage by weight: 0.1 to 0.4 percent of hydrofluoric acid, 40 to 60 percent of sulfuric acid, 0.2 to 0.4 percent of phosphoric acid, 1 to 2 percent of ammonium sulfate, 1.0 to 20.0 percent of acetic acid, 2.0 to 10.0 percent of nitric acid and the balance of deionized water. The comparison of the hole size of a flexible foldable glass product prepared by the method of the invention after laser cutting and punching with the hole size of the finished product is shown in table 1:

TABLE 1

The impact property and folding property of the flexible foldable glass prepared by the preparation method are tested, and the testing process is as follows:

impact performance test: and respectively and sequentially attaching the OCA optical cement and the PET film to the upper surface and the lower surface of the hole-digging sample to be detected to form an attaching structure, and placing marble at the lower end of the attaching structure, wherein the upper-down layer structure of the attaching structure is PET-OCA-sample-OCA-PET-marble. The pen point diameter is 0.5mm, the morning pen with the weight of 12-13g is used, the morning pen falls freely at positions with different heights and falls into a well-attached test sample, the appearance of a non-folding area of the y sample is observed, no crack is judged to be OK, at the moment, the distance between the pen point and an attached structure is a physical quantity representing the pen-down impact strength of the sample, and the larger the distance is, the stronger the impact resistance of the sample is indicated. The pen-down impact strength of the non-folding area of the flexible foldable glass prepared by the preparation method is measured to be 120-130cm.

Bending performance test: the UTG sample is adhered to a U-shaped dynamic bending machine jig by using an adhesive tape, the bending speed is set for 2s for one cycle, the bending radius is 1-5 mm, the sample is placed under the room temperature condition for 20w times of bending, no appearance defects such as cracks and folds are judged to be OK after bending, the corresponding bending radius and bending times are physical quantities representing the bending performance of the sample, the smaller the bending radius is, the more the bending times are, the stronger the bending performance of the sample is, the bending radius of a bending area of the bent glass prepared by the preparation method is 1-2mm, and the bending times are 200k times without breakage.

Compared with the ultrathin glass with the thickness less than 100 mu m, the flexible foldable glass prepared by the preparation method has high shock resistance, and the glass thickness adopted in the processing process is more than or equal to 100 mu m, so that the process yield is higher, the production cost is lower, and the commercialization is more facilitated. Secondly, the folding glass cover plate can realize the inner bending and the outer bending of glass at the same time, and does not limit the folding direction of the glass. The above treatments can be carried out at a plurality of positions according to the folding requirement of the glass, so that the treated glass has the multi-form folding effect, and the problems of crease marks replacing CPI materials and excessively low UTG strength are effectively overcome.

The foregoing detailed description of a flexible foldable glass and method of making the same, with reference to the examples, is illustrative and not limiting, and several examples can be listed in the scope defined thereby and therefore variations and modifications within the scope of the invention should be considered as falling within the scope of the invention.

Claims

1. A method of making a flexible foldable glass, the method comprising the steps of:

(1) Covering the surface of the glass with an acid-resistant protective film;

(2) Performing laser drilling treatment on a target folding area of the glass;

(3) Chemically etching the glass treated in the step (1);

(4) Removing the acid-resistant protective film;

(5) Tempering the glass treated in the step (4);

(6) And (5) carrying out surface etching on the glass treated in the step (5).

2. The method according to claim 1, wherein in the step (1), the glass has a thickness of 100 to 500. Mu.m.

3. The method according to claim 1, wherein in the step (2), the holes punched are distributed in the target bending region of the glass in an array arrangement.

4. The method according to any one of claims 1 to 4, wherein the shape and size of each hole are identical; the shape of each hole is a waist hole, and each waist hole is perpendicular to the bending direction of the glass.

5. The method according to any one of claims 1 to 4, wherein in the step (2), the intended bending region of the glass is cut and perforated by an ultraviolet laser cutter.

6. The method according to any one of claims 1 to 4, wherein in the step (4), the acid etching rate is controlled to be 1 to 2 μm/min during the chemical etching treatment; an ultrasonic device is arranged in the etched groove body.

7. The method according to any one of claims 1 to 4, wherein in the step (5), the tempering treatment is performed under the following conditions: preheating at 370-400 deg.c for 30-60min, and tempering at 380-410 deg.c for 60-90min.

8. The method according to any one of claims 1 to 4, wherein in the step (6), the surface etching amount is controlled to be 4 to 8 μm, the etching rate is 0.5 to 0.8 μm/min, and the surface roughness of the flexible foldable glass after the surface etching process is 0.2 to 0.30 μm.

9. The method according to any one of claims 1 to 4, wherein the step (1) is preceded or followed by a step of laser cutting the glass and CNC edge treatment.

10. A flexible foldable glass prepared by the preparation method according to any one of claims 1 to 9.