Multi-directionally bendable fatigue-resistant electronic glass and preparation method thereof

Abstract

The application discloses a multi-directional bending fatigue-resistant electronic glass and a preparation method thereof. The preparation method comprises the following steps: pre-soaking liquid cleaning and water washing, chemical thinning after film protection, then local high-temperature annealing and tensile thinning, and finally chemical toughening to obtain the multi-directional bending fatigue-resistant electronic glass. The chemical thinning is to etch both sides of the electronic glass to obtain double-sided symmetrical etching grooves. The electronic glass is treated by adopting a two-stage processing method of chemical thinning and local high-temperature annealing+tensile thinning, so that the bending resistance of the electronic glass is improved, and the double-sided bending of the electronic glass is realized.

Description

Technical Field

[0001] This invention belongs to the field of electronic display device technology, specifically relating to a multi-directionally bendable and fatigue-resistant electronic glass and its preparation method. Background Technology

[0002] Electronic glass, generally referring to ultra-thin float glass with a thickness of less than 2mm, is a high-tech product applicable to the fields of electronics, microelectronics, and optoelectronics. It is primarily used in the manufacture of integrated circuits and glass materials with optoelectronic, thermoelectric, acousto-optic, and magneto-optical functions. With the rapid development of the foldable display market, manufacturers are launching new foldable screen products almost every quarter. This places increasingly higher demands on the bendable electronic glass used in foldable display devices. It not only needs to meet optical performance requirements such as high light transmittance but also possesses excellent mechanical properties such as scratch resistance, drop resistance, resistance to repeated bending, and minimal creases.

[0003] Chinese patent CN117776519A discloses an ultrathin flexible reinforced glass and its preparation method. The glass comprises, by mass percentage of oxides: 57.5-61.8% SiO2, 13.9-15.2% Al2O3, 12.1-13.2% Na2O, 6.2-7.2% MgO, 5.5-6.4% K2O, and 0.4-1.0% ZrO2. The limiting bending radius is 4-13 mm, and the bending pressure it can withstand is 400-840 MPa.

[0004] Chinese patent CN113173708A discloses a processing method for improving the bending performance of flexible glass, comprising the following steps: cutting, etching, debonding, and chemically tempering multilayered flexible glass to obtain flexible glass with enhanced bending performance; wherein, the multilayered flexible glass includes a bottom plate and at least one repeating unit layer bonded to the top of the bottom plate, the repeating unit layer including a lower layer of flexible glass and a substrate bonded to the upper layer of the flexible glass, and the repeating unit layers are bonded together. The final bending breakage rate is only 1-2%.

[0005] Existing bendable electronic glass is generally of uniform thickness, 20-40μm. Although it can meet the requirements for flexible folding at the phone hinge, the excessive thinness of the entire glass results in insufficient scratch resistance and bending resistance on the front of the phone screen, which greatly affects the user experience. In addition, although some scholars have proposed the concept of bendable electronic glass with unequal thickness, the stress concentration in the unequal thickness joint area cannot be properly handled, which can easily lead to breakage of the electronic glass during use. Moreover, existing bendable electronic glass with unequal thickness can only meet unidirectional folding and cannot be used for the display requirements of future multidirectional foldable electronic display devices. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a multi-directionally bendable and fatigue-resistant electronic glass and its preparation method. The electronic glass is treated using a two-stage process of chemical thinning and local high-temperature annealing followed by stretching thinning, which improves the bend resistance of the electronic glass and enables double-sided bending.

[0007] To achieve the above objectives, the present invention provides a method for preparing multi-directionally bendable and fatigue-resistant electronic glass, comprising the following steps:

[0008] (1) Pre-cleaning: The electronic glass substrate is placed in the pre-soaking solution for cleaning, and then rinsed with water;

[0009] (2) Film protection: Apply UV film to both sides of the pre-cleaned electronic glass sheet, while leaving two uncoated areas on both sides;

[0010] (3) Chemical thinning: The electronic glass is chemically thinned by top spraying acid solution, forming etched grooves in the non-coated area;

[0011] (4) Cleaning: After removing the UV film, clean it a second time with the pre-soaking solution;

[0012] (5) Local annealing: The etched grooves of the electronic glass are heated, and then local high-temperature annealing and stretching are performed;

[0013] (6) Chemical tempering: The stretched and thinned electronic glass is placed in a tempering solution for tempering, and then cleaned.

[0014] Preferably, the electronic glass substrate in step (1) is high-alumina electronic glass, wherein the mass fraction of aluminum is 9.7-14.8%.

[0015] Preferably, the water washing in step (1) includes the following steps:

[0016] S1: Spraying with medicine;

[0017] S2: Air cutting + deionized water rinsing;

[0018] S3: Ultrasonic cleaning.

[0019] Preferably, the pre-soaking solution described in steps (1) and (4) consists of 2-8% hydrofluoric acid, 7-15% auxiliary acid and 80-85% deionized water: the auxiliary acid is one or more of sulfuric acid, oxalic acid and hydrochloric acid.

[0020] More preferably, the auxiliary acid is composed of 40-60% sulfuric acid, 25-35% oxalic acid, and 15-20% hydrochloric acid.

[0021] Preferably, the cleaning conditions described in steps (1) and (4) are cleaning at 30-50°C for 10-15 minutes.

[0022] Preferably, the width of the uncoated area in step (2) is 1-5 mm and the distance from the edge of the electronic glass is 50-100 mm.

[0023] Preferably, the acid solution in step (3) is composed of 5-17% hydrofluoric acid and 9-20% auxiliary acid: the auxiliary acid is one or more of sulfuric acid, oxalic acid and nitric acid; the chemical thinning rate is 1.8-3 μm / min and the thinning time is 100-150 min.

[0024] More preferably, the auxiliary acid is composed of 8-11% sulfuric acid, 5-6% oxalic acid, 1-3% nitric acid and deionized water.

[0025] More preferably, the depth of the etched groove after chemical thinning is 280-300 μm, and the glass thickness at the etched groove after chemical thinning is 10-15% of the thickness of the unetched area.

[0026] Preferably, the UV film removal step (4) involves irradiating the film with ultraviolet light for 1-2 minutes.

[0027] Preferably, the local high-temperature annealing conditions in step (5) are 400-600℃ for 3-8 minutes; the tensile force for the stretching and thinning is 3-6N.

[0028] Preferably, the tempering temperature in step (6) is 390-450℃ and the tempering time is 1.5-3h.

[0029] The present invention also provides a multi-directional bendable fatigue-resistant electronic glass, wherein the multi-directional bendable fatigue-resistant electronic glass has symmetrical bending groove areas on its A and B surfaces.

[0030] Preferably, the width of the bending groove area is 1-5mm, the depth is 280-300μm, the bidirectional bending radius is 0.8-1.3mm, and the number of bending groove areas is ≥2.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. The electronic glass is treated with a two-stage process of chemical thinning and local high-temperature annealing + stretching thinning, which effectively avoids stress concentration at the junction of the bending area and the screen area, greatly improves the bending fatigue life of the electronic glass, and enhances the mechanical properties of the display screen such as scratch resistance and impact resistance.

[0033] 2. By simultaneously fabricating bending groove areas on both sides of the electronic glass, bidirectional folding of the electronic glass is achieved, which broadens the application range of multi-directional folding of foldable electronic display devices and can meet the diversified development needs of electronic display devices. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of UV film adhesion.

[0035] Figure 2 This is a schematic diagram of the structure of the multi-directionally bendable and fatigue-resistant electronic glass prepared in Example 1.

[0036] In the diagram, 1 is the A side of the electronic glass, 2 is the B side of the electronic glass, 3 is the bending groove area, 4 is the electronic glass, 5 is the uncoated area, and 6 is the UV film. Detailed Implementation

[0037] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the contents of the claims. Modifications and substitutions made by those skilled in the art to the technical solution of the present invention without creative effort all fall within the scope of protection of the present invention.

[0038] Example 1

[0039] (1) Take a high-alumina ultra-thin electronic glass sheet with a size of 100×180×0.33mm and place it in a pre-soaking solution and soak it at 40℃ for 10min; the pre-soaking solution includes 5% hydrofluoric acid, 7% auxiliary acid, and the remainder is deionized water; the auxiliary acid is composed of 50% sulfuric acid, 30% oxalic acid, and 20% hydrochloric acid.

[0040] (2) Clean the electronic glass substrate after it has been pre-soaked in the solution. The specific steps include:

[0041] S1: Chemical spray: The chemical solution consists of 0.05% sodium hydroxide and deionized water; the spraying method is vertical spraying from the top; the spraying flow rate is 500 mL / min; the spraying time is 30-50 s;

[0042] S2: Air cutting + deionized water rinsing: The air velocity during air cutting is 3m / s, the water flow rate for deionized water rinsing is 10L / min, and the total treatment time is 10s.

[0043] S3: Ultrasonic cleaning: frequency 80kHz, time 45s);

[0044] S4: Circulating water washing: Ultrapure water is used for circulating water washing, with the spray method being vertical spraying from the top. The single water washing time is 45 seconds, and the number of cycles is 5.

[0045] S5: High-temperature air knife drying: Temperature 50℃; Air velocity 5m / s; Processing time 55s)

[0046] (3) Apply UV film to both sides of the electronic glass substrate, and leave two uncoated areas on both sides. The width of the uncoated areas is 1 mm and the distance from both sides of the electronic glass substrate is 50 mm.

[0047] (4) The electronic glass substrate is chemically thinned on both sides by top spraying, forming symmetrical etching grooves with a depth of 280 μm on both sides of the glass, with a thinning rate of 2 μm / min; the acid formula for chemical thinning is: 5% hydrofluoric acid, 10% sulfuric acid, and the remainder is deionized water.

[0048] (5) Irradiate the double-sided chemically thinned electronic glass sheet with a UV curing lamp for 1 minute to remove the UV film, and repeat the cleaning step (2).

[0049] (6) The electronic glass substrate obtained in step (5) is locally heated to 500°C and held for 5 min. At the same time, a tensile force of 5N is applied to both sides of the electronic glass substrate for 5 min to perform local high-temperature annealing. The local heating rate is 10°C / min. The local heating is limited to the etched groove.

[0050] (7) Place the electronic glass sheet obtained in step (6) in tempering solution at 390°C for 1.5 hours and repeat step (2) for cleaning to obtain electronic glass that can be bent in multiple directions and is fatigue resistant. The tempering solution is made of potassium nitrate molten salt.

[0051] Example 2

[0052] The method and steps are the same as in Example 1, except that some preparation conditions are changed, as follows:

[0053] The formula of the pre-soaking solution in step (1) is changed to 6% hydrofluoric acid, 7% auxiliary acid, and the remainder is deionized water. The soaking temperature is changed to 30℃ and the soaking time is changed to 15min. The auxiliary acid is composed of 60% sulfuric acid, 25% oxalic acid and 15% hydrochloric acid.

[0054] The width of the uncoated area in step (3) is changed to 3mm;

[0055] The thinning rate in step (4) is 2.2 μm / min, the depth of the etched groove is 290 μm, and the acid solution formula for chemical thinning is 5% hydrofluoric acid, 20% auxiliary acid, and the remainder is deionized water; wherein the auxiliary acid is composed of 8% sulfuric acid, 5% oxalic acid, 1% nitric acid and deionized water;

[0056] In step (6), the temperature is changed to 400℃, the heat preservation time is changed to 8min, and the tensile force is changed to 3N;

[0057] The tempering temperature in step (7) is changed to 420℃ and the heat preservation time is changed to 2h.

[0058] Example 3

[0059] The method and steps are the same as in Example 1, except that some preparation conditions are changed, as follows:

[0060] The formula of the pre-soaking solution in step (1) is changed to 7% hydrofluoric acid, 10% auxiliary acid, and the remainder is deionized water. The soaking temperature is changed to 50℃ and the soaking time is changed to 12min. The auxiliary acid is composed of 40% sulfuric acid, 35% oxalic acid and 15% hydrochloric acid.

[0061] The width of the uncoated area in step (3) is changed to 5 mm;

[0062] The thinning rate in step (4) is 2.5 μm / min, the depth of the etched groove is 300 μm, and the acid solution for chemical thinning is composed of 17% hydrofluoric acid, 9% auxiliary acid and deionized water; wherein the auxiliary acid is composed of 11% sulfuric acid, 6% oxalic acid, 3% nitric acid and deionized water.

[0063] In step (6), the temperature is changed to 600℃, the heat preservation time is changed to 3min, and the tensile force is changed to 6N;

[0064] The tempering temperature in step (7) is changed to 450℃ and the heat preservation time is changed to 3h.

[0065] Comparative Example 1

[0066] The method and steps are the same as in Example 1, except that the uncoated area in step (3) is changed to two lines on one side, and step (6) is omitted, and electronic glass is prepared.

[0067] Comparative Example 2

[0068] The method and steps are the same as in Example 1, except that the uncoated area in step (3) is changed to two lines on one side to prepare electronic glass.

[0069] Comparative Example 3

[0070] The method and steps are the same as in Example 1, except that step (6) is omitted, and electronic glass is prepared.

[0071] Comparative Example 4

[0072] The method and steps are the same as in Example 1, except that the stretching and thinning in step (6) is omitted, and electronic glass is prepared.

[0073] Comparative Example 5

[0074] The method and steps are the same as in Example 1, except that step (3) is omitted and UV film is not applied to prepare electronic glass.

[0075] Results and Testing: The electronic glass prepared in the above examples and comparative examples was visually inspected for its groove morphology, tested for its bending performance using a bending tester, tested for its scratch resistance using the scratch test (referring to GB / T 39815-2021 (Test Method for Scratch Resistance of Ultra-thin Glass)), tested for its impact resistance using the pen drop test (referring to GB / T 39814-2021 (Test Method for Impact Strength of Ultra-thin Glass)), and tested for its stress performance in the bending area and screen area using GB / T 44752-2024 (Test Method for Bending Fatigue of Flexible Glass). The results are shown in the table below:

[0076]

[0077] As can be seen from the data in the table, electronic glass that has undergone two-stage processing of chemical thinning and physical annealing can meet the requirements of multi-directional folding. Compared with the comparative example, it has significantly reduced the stress concentration at the edge of the groove, has a smaller bending radius, and has better fatigue resistance.

Claims

1. A method for preparing multi-directionally bendable and fatigue-resistant electronic glass, characterized in that: Includes the following steps: (1) Pre-cleaning: The electronic glass substrate is placed in the pre-soaking solution for cleaning, and then rinsed with water; (2) Film protection: Apply UV film to both sides of the pre-cleaned electronic glass sheet, while leaving two uncoated areas on both sides; (3) Chemical thinning: The electronic glass is chemically thinned by top spraying acid solution, forming etched grooves in the non-coated area; (4) Cleaning: After removing the UV film, clean it a second time with the pre-soaking solution; (5) Local annealing: The etched grooves of the electronic glass are heated, and then local high-temperature annealing and stretching are performed; (6) Chemical tempering: The stretched and thinned electronic glass is placed in a tempering solution for tempering and then cleaned; the local high temperature annealing conditions in step (5) are 400-600℃ for 3-8 minutes; the tensile force for stretching and thinning is 3-6N.

2. The preparation method according to claim 1, characterized in that: The pre-soaking solution described in steps (1) and (4) consists of 2-8% hydrofluoric acid, 7-15% auxiliary acid and 80-85% deionized water; the auxiliary acid is one or more of sulfuric acid, oxalic acid and hydrochloric acid.

3. The preparation method according to claim 1, characterized in that: The cleaning conditions described in steps (1) and (4) are 30-50℃ for 10-15 minutes.

4. The preparation method according to claim 1, characterized in that: The width of the uncoated area in step (2) is 1-5mm, and the distance from the edge of the electronic glass is 50-100mm.

5. The preparation method according to claim 1, characterized in that: The acid solution in step (3) consists of 5-17% hydrofluoric acid and 9-20% auxiliary acid: the auxiliary acid is one or more of sulfuric acid, oxalic acid and nitric acid, the chemical thinning rate is 1.8-3 μm / min, and the thinning time is 100-150 min.

6. The preparation method according to claim 1, characterized in that: The UV film removal step (4) involves irradiating the film with ultraviolet light for 1-2 minutes.

7. The preparation method according to claim 1, characterized in that: The tempering temperature in step (6) is 390-450℃ and the tempering time is 1.5-3h.

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