TW202348573A - Strengthened lithium-free aluminoborosilicate glass - Google Patents

Abstract

The present invention describes a strengthened lithium-free aluminoborosilicate glass. The lithium-free aluminoborosilicate glass undergoes a double ion-exchange process to achieve a depth of compressive layer greater than 50 [mu]m. The chemically strengthened aluminoborosilicate glass survives during a greater number of device drops before failure.

Description

Strengthened lithium-free aluminum borosilicate glass

This invention describes an aluminoborosilicate glass. More specifically, the present invention focuses on lithium-free glass compositions. The present invention describes a lithium-free glass composition that exhibits higher strength through a dual ion exchange strengthening process.

In recent years, electronic devices equipped with liquid crystal displays, organic light emitting diode displays, or the like have been widely used. Since glass materials have high surface hardness, they are widely used as cover glass materials for displays of such electronic devices. Because glass is a typically brittle material, such cover glass typically undergoes a strengthening process. There is a continued focus on reducing the thickness and weight of electronic devices, creating a need for thinner cover glass.

Chemical strengthening is an important strengthening process used for glass sheets. For thin sheets of glass such as the cover glass of a display, chemical strengthening is often used to strengthen the cover glass. In the chemical strengthening process, glass containing monovalent alkali metal ions on the surface is immersed in a molten salt bath at high temperatures. During the manufacturing process, monovalent alkali metal ions with a larger radius in the salt bath can replace monovalent alkali metal ions with a smaller radius on the glass surface, thereby forming a compressive stress layer on the glass surface. The greater dense accumulation of monovalent alkali metal ions at the glass surface subsequently creates high compressive stresses, which in turn provide greater strength. The compression layer further serves to suppress defects that can cause glass failure, including low tensile strength.

In recent years, lithium aluminosilicate glass has been widely used as cover glass for displays used in electronic devices due to its superior mechanical properties over lithium-free glass. Specifically, excellent mechanical properties are achieved by the fact that the smallest lithium ion among the alkali metal ions can first undergo ion exchange by becoming the next larger ion after the lithium ion, the sodium ion, and then the sodium ion double In the ion exchange (DIOX) process, the next larger ion, potassium ion, undergoes another ion exchange. The entire DIOX process, which is possible due to the presence of lithium ions, produces increased compression depth and can achieve larger surface compressive stresses. However, there is a huge demand for lithium due to its widespread use in battery packs that power smartphones, laptops, electric vehicles and the like. The huge demand for lithium has exceeded its supply, causing the procurement cost of lithium to increase. Furthermore, it has been predicted that lithium will soon be insufficient to meet its existing demand. Accordingly, the present invention focuses on methods or processes for enhancing the performance of lithium-free aluminoborosilicate glasses. Therefore, there is a need for lithium-free aluminoborosilicate glasses that exhibit the desired surface compressive stress and layer depth when undergoing ion exchange. Invention goal

Some of the objects of the invention are described herein. It is an object of the present invention to provide an aluminoborosilicate glass composition. Another object of the present invention is to provide an aluminoborosilicate glass that is substantially free of lithium.

Another object of the present invention is to subject lithium-free aluminoborosilicate glass to a dual ion exchange process to achieve a compression layer depth greater than 50 μm.

Another object of the present invention is to provide lithium-free aluminum borosilicate compositions with higher strength and better service life.

Other objects and advantages of the invention will become more apparent from the following description, which is not intended to limit the scope of the invention.

In one embodiment of the present invention, an aluminoborosilicate glass composition is disclosed. Aluminoborosilicate glass compositions that are substantially free of lithium are disclosed.

In one embodiment, the glass composition of the lithium-free aluminoborosilicate glass includes SiO ₂ in the range of about 40 to about 70 wt %, and Al ₂ O in the range of about 5 to about 35 wt %. ₃ and B ₂ O ₃ in the range of about 0.5% to about 10% by weight. Furthermore, it includes alkali metal oxides, such as Na ₂ O in the range of about 5 to about 25 wt % and K ₂ O in the range of about 0 to about 5 wt %, and alkaline earth metal oxides, Such as MgO in the range of about 0 wt% to about 7 wt%. In addition, it includes P ₂ O ₅ in the range of about 0 to about 10 wt %, ZrO ₂ in the range of about 0 to about 6 wt %, and SnO ₂ in the range of about 0 to about 2 wt %. , Fe ₂ O ₃ in the range of about 0 to about 3 wt %, CeO ₂ in the range of about 0 to about 3 wt %, and TiO ₂ in the range of about 0 to about 5 wt %.

In one embodiment, lithium-free aluminoborosilicate glass can exhibit higher strength when it undergoes a dual ion exchange process.

In one embodiment, lithium-free aluminoborosilicate glass undergoes a dual ion exchange process to achieve a compression layer depth greater than 50 μm.

In one embodiment, lithium-free aluminoborosilicate glass has better durability, higher crack resistance, and higher sharp impact strength. Additionally, the glass can survive a larger number of device drops before failing.

In one embodiment, lithium-free aluminoborosilicate glass may be used as a substrate for touch panel displays and for back covers of such displays, such as liquid crystal displays (LCDs), field emission displays (FED), electronic Plasma display (PD), electroluminescent display (ELD), organic light emitting diode (OLED) display, micro LED or the like. Lithium-free aluminoborosilicate glass is used for the protection of electronic devices with display screens, such as mobile phones, entertainment devices, tablets, laptops, digital cameras, wearable devices, or the like.

These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description.

priority statement

This application claims priority over Indian Provisional Application Serial No. 202221022507 filed on April 15, 2022. The entire content of this provisional application is incorporated herein by reference.

In the following description, the same reference numerals represent the same or corresponding parts throughout the several views shown in the drawings. It is also understood that, unless otherwise specified, terms such as "top," "bottom," "outer," "inner," and the like are terms of convenience and should not be construed as limiting terms. Furthermore, whenever a group is described as comprising at least one of a group of elements and combinations thereof, it is to be understood that the group may include, consist essentially of, any number of those elements, individually or in combination with each other. or consisting of. Similarly, whenever a group is described as consisting of at least one or combination of elements of a group, it is to be understood that the group may consist of any number of those elements, individually or in combination with each other. Unless stated otherwise, when a range of values is recited, it includes the upper and lower limits of the range and any range therebetween. As used herein, the indefinite article "a/an" and the corresponding definite article "the" mean "at least one" or "one or more" unless otherwise stated. It should also be understood that the various features disclosed in the description and drawings may be used in any and all combinations.

As used herein, the term "glass article/glass articles" is used in its broadest sense to include any article made entirely or partially of glass. Unless otherwise specified, all compositions are expressed as weight percent (wt%). All temperatures are expressed in degrees Celsius (°C) unless otherwise stated. Unless otherwise stated, the coefficient of thermal expansion (CTE) is expressed as 10 ⁻⁷ /°C and represents a value measured over a temperature range of about 50°C to about 300°C.

It should be noted that the terms "substantially" and "approximately" may be used herein to indicate the inherent degree of uncertainty attributable to any quantitative comparison, value, measurement or other representation. These terms are also used herein to indicate the extent to which a quantitative representation may differ from the stated reference without resulting in a change in the essential functionality of the subject matter discussed. For example, a glass that is "substantially free of Li ₂ O" is a glass in which Li ₂ O is not actively added or added in batches to the glass, but may be present in a very small amount as a contaminant from the raw material.

Recently, with the advancement of technology, electronic devices such as mobile phones, tablet computers, wearable devices, digital cameras or the like are widely used. These electronic devices have display screens protected by cover glasses of different compositions. The present invention describes a lithium-free aluminum borosilicate glass composition that provides a display screen with better service life.

The present invention describes in detail various lithium-free aluminum borosilicate glass compositions. The present invention generally describes lithium-free aluminum borosilicate glasses and compositions thereof. Glass compositions _include one or more chemical components such as _SiO2 , _{Al2O3 ,} and _B2O3 . The glass composition further includes an alkali metal oxide selected from the group consisting of Na ₂ O and K ₂ O. Additionally, the glass composition includes one or more basic oxides, such as MgO, CaO, SrO, and BaO. It may also contain other chemical components such as ZrO ₂ , Fe ₂ O ₃ , CeO ₂ , P ₂ O ₅ , TiO ₂ or the like. Furthermore, it may also contain refining agents such as _SnO2 , chlorides, sulfates or the like. The properties of lithium-free aluminum borosilicate glasses are highly affected by the amounts of components in the glass composition.

In one embodiment, SiO ₂ is a component that forms the glass network structure. When the SiO ₂ content is too high, the glass is difficult to melt and shape, or the glass has a thermal expansion coefficient that is too low, and it is difficult to have the same thermal expansion coefficient as the surrounding materials. On the other hand, when the SiO ₂ content is too low, vitrification is difficult. In addition, such glasses have an increased coefficient of thermal expansion, which tends to reduce thermal shock resistance. Therefore, the glass composition requires an optimal weight % of _SiO2 . For example, the glass composition may include about 40% to about 70% by weight _SiO2 .

In one embodiment, Al ₂ O ₃ is a component that enhances the suitability of single and/or multiple ion exchanges. Al ₂ O ₃ further enhances the heat resistance and Young's Modulus of glass. In the case where the content of Al ₂ O ₃ is too high, devitrified crystals tend to separate in the glass, making it difficult to form the glass by an overflow down-draw process or the like. In addition, such glasses have increased viscosity at high temperatures and are difficult to melt. When the content of Al ₂ O ₃ is too low, it is possible that the glass may not be sufficiently suitable for single and/or multiple ion exchange. In these respects, the glass composition requires an optimal weight % of Al ₂ O ₃ . For example, the glass composition may include from about 5% to about 35% by weight Al ₂ O ₃ .

In one embodiment, B ₂ O ₃ is a component that has the function of reducing the liquidus temperature, high temperature viscosity and density of the glass, and further has the function of enhancing the suitability of the glass for single and/or multiple ion exchange. Furthermore, the presence of B ₂ O ₃ causes the depth of the compressive stress layer formed by chemical strengthening to decrease. In these respects, the glass composition requires an optimal weight % of B ₂ O ₃ . For example, the glass composition may include from about 0.5% to about 10% by weight B ₂ O ₃ .

In one embodiment, Na ₂ O is a component used in chemical strengthening treatment to increase the surface compressive stress and the depth of the surface compressive stress layer by replacing sodium ions with potassium ions. However, increasing the _Na2O content beyond appropriate limits results in a situation where surface compressive stress may be reduced. In these respects, the glass composition requires an optimal weight % of _Na2O . For example, the glass composition may include from about 5% to about 25% by weight _Na2O .

Similar to Na ₂ O, K ₂ O is a component that increases the meltability of the glass. Reducing the K ₂ O content increases the ion exchange rate in chemical strengthening and thereby increases the depth of the surface compressive stress layer, but at the same time decreases the liquidus temperature TL of the glass composition. Therefore, K ₂ O is preferably contained in a small amount. In these respects, the glass composition requires an optimal weight % of _K2O . For example, the glass composition may include from about 0% to about 5% by weight _K2O .

Furthermore, aluminoborosilicate glasses are essentially free of lithium, that is to say in particular Li ₂ O. Since the presence of Li ₂ O improves the Young's modulus and fracture toughness of the glass, the content of Al ₂ O ₃ is adjusted to improve the Young's modulus of the lithium-free aluminum borosilicate glass.

In one embodiment, MgO is an alkaline earth metal, and the content of MgO may be about 0% to about 7% by weight. In one embodiment, _P2O5 is a component that enhances the suitability of the glass for ion exchange and _is highly effective, particularly in increasing the depth of the compressive stress layer. Since higher P ₂ O ₅ content can cause phase separation in the glass or can impair water resistance, the glass composition may include about 0 to about 10 wt % P ₂ O ₅ .

In one embodiment, the glass composition further includes one or more refining agents, such as about 0% to about 2% by weight SnO ₂ and about 0% to about 3% by weight Fe ₂ O ₃ . Furthermore, it may also include other refining agents such as CeO ₂ , chlorides, sulfates or the like. In one embodiment, the glass composition may include about 0% to about 6% by weight ZrO ₂ and about 0% to about 5% by weight TiO ₂ . In one embodiment, the thickness of the lithium-free aluminoborosilicate glass obtained from the above-listed glass composition is in the range of 20 microns to 2 mm.

Table 1 illustrates the following non-limiting, exemplary lithium-free aluminum borosilicate glass compositions and their properties: weight% 1 2 3 4 5 6 7 8 SiO ₂ 62.10 61.95 61.79 62.07 62.09 61.99 62.00 62.60 Al ₂ O ₃ 19.70 19.65 19.60 18.71 18.72 18.69 18.69 18.25 B ₂ O ₃ 3.60 3.59 3.58 3.72 3.72 3.72 3.72 2.96 Na ₂ O 13.10 13.06 13.03 14.01 14.01 13.99 13.99 15.00 Li ₂ O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 K ₂ O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 MgO 1.40 1.40 1.39 1.14 1.14 1.14 1.14 1.00 P ₂ O ₅ 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZrO ₂ 0.00 0.06 0.06 0.06 0.06 0.06 0.06 0.00 TiO ₂ 0.00 0.06 0.06 0.06 0.06 0.06 0.06 0.00 Fe ₂ O ₃ 0.00 0.05 0.05 0.05 0.02 0.05 0.02 0.00 CeO ₂ 0.00 0.00 0.26 0.00 0.00 0.13 0.13 0.00 SnO ₂ 0.14 0.18 0.18 0.18 0.18 0.18 0.18 0.19 total 100.04 100.00 100.00 100.00 100.00 100.00 100.00 100.00 characteristic Tg ( ℃) 618 - 626 611 611 - 620 - CTE (×10 ^-7 ) / ℃ (50- 300 ℃) 75.8 - 75.6 79.5 79.0 - 76.9 - Density(g/cc) 2.39 - 2.41 2.41 2.41 - 2.41 2.42 Young's modulus (GPa) 69.3 - 70.8 70.1 70.0 - 70.1 69.7 Annealing T. ( ℃) 628 - 636 621 621 - 630 - Poisson's ratio 0.22 - 0.22 0.23 0.23 - 0.22 0.23 Shear modulus (GPa) 28.4 - 28.5 28.5 28.5 - 28.8 28.3 Table 1: Exemplary glass compositions and their properties

Table 2 illustrates the following non-limiting, exemplary aluminoborosilicate glass compositions and their properties: weight% 9 10 11 12 13 14 15 SiO ₂ 62.12 61.87 62.00 48.11 52.95 52.56 42.64 Al ₂ O ₃ 18.22 19.63 19.00 26.04 19.97 26.07 31.27 B ₂ O ₃ 4.26 3.99 3.70 4.28 4.54 4.29 4.19 Na ₂ O 14.22 13.41 13.80 18.54 15.39 13.96 18.15 Li ₂ O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 K ₂ O 0.00 0.00 0.00 0.10 3.86 0.20 0.10 MgO 1.00 0.92 1.15 0.67 0.75 0.67 1.31 P ₂ O ₅ 0.00 0.00 0.00 2.21 2.48 2.21 2.16 ZrO ₂ 0.00 0.00 0.06 0.00 0.00 0.00 0.00 TiO ₂ 0.00 0.00 0.06 0.00 0.00 0.00 0.00 Fe ₂ O ₃ 0.00 0.00 0.05 0.00 0.00 0.00 0.00 CeO ₂ 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SnO ₂ 0.19 0.19 0.18 0.05 0.05 0.05 0.17 total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 characteristic Tg ( ℃) 604 - - 617 - - 657 CTE (×10 ^-7 ) / ℃ (50-300 ℃) 77.5 - - 95.0 - - 94.0 Density(g/cc) 2.42 2.41 - 2.44 - - 2.44 Young's modulus (GPa) 71.9 69.1 - 67.5 - - 70.5 Annealing T. ( ℃) 614 - - 627 - - 667 pasombi 0.21 0.23 - 0.23 - - 0.24 Shear modulus (GPa) 29.6 28.1 - 27.4 - - 28.4 Table 2: Exemplary glass compositions and their properties

In an exemplary embodiment, when the glass composition includes about 42.64% by weight SiO ₂ , about 31.27% by weight Al ₂ O ₃ , about 4.19% by weight B ₂ O ₃ , about 18.15% by weight Na ₂ O, Lithium-free aluminoborosilicate glass obtained from a glass composition containing about 0.10% by weight of K ₂ O, about 1.31% by weight of MgO, about 0.17% by weight of SnO ₂ and about 2.16% by weight of P ₂ O ₅ The glass transition temperature (Tg) is about 657°C, the CTE is about 94×10 ^-7 /°C, the density is about 2.44 g/cc, the Young’s modulus is about 70.5 GPa, the annealing temperature is about 667°C, and the Passon ratio is about 0.24, and the shear modulus is about 28.4 GPa.

Lithium-free aluminum borosilicate glass can undergo two ion exchange process steps. In one embodiment, the ion exchange process is based on the size of monovalent alkali metal ions. Lithium-free aluminum borosilicate glass containing monovalent alkali metal ions is treated at high temperature in a molten salt bath containing an alkali metal inorganic salt. Here, the monovalent alkali metal ions on the glass surface of the glass perform ion exchange with the monovalent alkali metal ions of the alkali metal inorganic salt. A common process is to immerse the glass in a molten salt bath of alkali metal inorganic salts or a mixture of alkali metal inorganic salts and other inorganic salts. The immersion time is sufficient to cause this exchange only in the surface layer of the glass object. The high compressive stress achieved through the ion exchange process helps the glass survive a larger number of device drops before failure.

When larger alkali metal ions replace smaller alkali metal ions in the surface layer of the glass at elevated temperatures below the strain point of the glass, the surface layer subsequently acquires compressive stress. The larger alkali metal ions attempt to occupy the space previously occupied by the smaller alkali metal ions, thereby creating compressive stress at the surface layer of the glass. Because the temperature of the molten salt bath is below the glass's strain point, the glass cannot readjust itself to relieve stress. Lithium-free aluminum borosilicate glass undergoes a dual ion exchange process. The following are two steps of the dual ion exchange process: ion exchange step I :

The glass composition of the present invention is rich in Na+ ions and deficient in K+ ions. In the first step I of the double ion exchange process, the K+/Na+ ratio of the alkali metal salt used in the molten salt bath is higher than the K+/Na+ ratio in the glass. Therefore, a first step I is performed to replace the smaller alkali metal ions (Na+ ions) on the glass surface with larger alkali metal ions (K+ ions) in the molten salt bath. In the first step I of the dual ion exchange process, alkali metal salts such as sodium nitrate (NaNO ₃ ) and potassium nitrate (KNO ₃ ) are used in the ion exchange bath. Here, the K+ ions of the alkali metal inorganic salt replace the Na+ ions in the surface layer of the glass. Since the ion exchange time is very long, that is, at least about 1 hour or about more than 4 hours, the Na+ ions in the glass are initially replaced by K+ ions in the ion exchange bath, so that the glass surface is enriched with K+ ions. Further ion exchange causes K+ ions in the glass to be exchanged with Na+ ions in the ion exchange bath. This continuous process of exchanging K+ ions in the glass with Na+ ions in the ion exchange bath, and then exchanging Na+ ions in the glass with K+ ions in the ion exchange bath continues until the compression depth becomes greater than 50 μm and K+ in the glass The composition of the /Na+ ratio becomes the same as the K+/Na+ ratio in the ion exchange bath. Although the compressive stress becomes lower and lower with time and the ion exchange bath contains a mixture of Na+ and K+ ions, the compression depth of the glass contains the same ratio of Na+ and K+ ions as in the ion exchange bath. This imparts a greater depth of compression layer and a large amount of compressive stress. The compressive stress layer formed on the surface of the glass provides the glass with increased resistance to scratches and drops. Step II of ion exchange :

In the second step II of the ion exchange process, the K+/Na+ ratio is greater than 90%, which is much higher than the K+/Na+ ratio in the first step I of the ion exchange process. In the process of the present invention, some of the alkali metal salts used so far, such as potassium nitrate (KNO ₃ ) mixed with some sodium nitrate (NaNO ₃ ) - (in very high concentrations) provide liquid ions for the second step of ion exchange. Exchange bath. Here, the K+ ions of the alkali metal inorganic salt replace the Na+ ions in the surface layer of the glass. Due to the extremely high concentration of K+ ions and the extremely short ion exchange time (<60 minutes), this results in extremely high compressive stresses in the surface.

The aluminoborosilicate glasses described herein are substantially free of Li ₂ O when initially formed. When glass undergoes a double ion exchange process, a larger number of K+ ions replace the Na+ ions present on the surface of the glass. The dual ion exchange process of lithium-free aluminum borosilicate glass allows for an increased compressive stress layer on the glass surface compared to the single ion exchange process of lithium-free aluminum borosilicate glass. Double ion-exchanged glass has excellent mechanical properties similar to lithium aluminosilicate glass. Adjust the ion exchange conditions of the dual ion exchange process to achieve the desired compressive stress layer on the surface of the glass.

Table 3 illustrates exemplary samples, defining two steps of the ion exchange process for glass sample 5 with a thickness of 0.7 mm and the corresponding depth of compression (DOL_zero) and compressive stress (CS) for each step. Sample number Step 1 _ Step 2 _ SLP-2000 FSM-6000 Fitting data of SLP-2000 and FSM-6000 (PMC) CT (MPa) Salt ( wt %) Temperature ( ℃ ) time ( minutes ) Salt ( wt %) Temperature ( ℃ ) time ( minutes ) CS (MPa) DOL_zero (μm ) CS (MPa) DOL (μm) CS (MPa) DOL_zero (μm ) CS_TP (MPa) DOL_TP (μm) 1 75% KNO ₃ 415 130 97% KNO ₃ 380 20 158.43 134.53 940.01 11.58 940.00 135.36 143.56 6.55 66.62 2 75% KNO ₃ 415 130 97% KNO ₃ 380 20 177.65 133.38 - - 943.38 133.28 154.89 6.25 66.85 3 75% KNO ₃ 415 130 97% KNO ₃ 380 20 134.01 137.00 1014.38 8.85 1014.38 138.42 114.50 6.50 53.79 4 75% KNO ₃ 415 130 97% KNO ₃ 380 20 - - - - - - - - - 5 60% KNO ₃ 398 240 100% KNO ₃ 388 36 133.09 145.23 1398.14 13.24 1400.08 143.88 114.63 11.05 61.68 6 60% KNO ₃ 398 240 100% KNO ₃ 388 36 148.74 127.90 1403.09 13.38 1403.10 128.41 112.69 11.88 62.83 7 60% KNO ₃ 398 240 100% KNO ₃ 388 36 128.42 143.01 1402.32 13.17 1404.25 143.01 108.96 11.23 58.26 8 60% KNO ₃ 398 240 100% KNO ₃ 388 36 99.81 124.87 1408.51 13.19 1408.52 123.66 90.59 13.03 59.45 9 60% KNO ₃ 398 240 100% KNO ₃ 388 36 153.28 139.15 1379.28 11.73 1380.86 141.13 123.37 9.70 64.66 Table 3: Exemplary samples and DOL and CS for each step of the ion exchange process

In an exemplary embodiment, the glass composition undergoes two ion exchange process steps. In the first step of ion exchange, the glass undergoes the first step of the ion exchange process in a salt bath containing about 75% by weight KNO ₃ and about 25% by weight NaNO ₃ . The preferred temperature for treating the glass material is about 415°C, and the time for treating the glass material is about 130 minutes. The stress profile of the first step of ion exchange includes a compressive stress of approximately 158.43 MPa and a compression depth of approximately 134.53 μm. Furthermore, in the second step of ion exchange, the salt bath contains about 97% by weight KNO ₃ and about 3% by weight NaNO ₃ . The preferred temperature for treating the glass material is about 380°C, and the time for treating the glass material is about 20 minutes. The stress profile of the second step of ion exchange includes a compressive stress greater than 940.01 MPa and a compression depth greater than 11.58 μm. Lithium-free aluminum borosilicate glass undergoes a dual ion exchange process to achieve a compression layer depth greater than 50 μm.

The present invention allows lithium-free aluminum borosilicate glass to undergo a dual ion exchange process to obtain a surface layer strength equivalent to that of lithium aluminum borosilicate glass. The high compressive stress achieved through the dual ion exchange step helps the glass survive a larger number of device drops before failure.

Applications of aluminoborosilicate glass can be used as substrates for touch panel displays and for back covers of such displays such as liquid crystal displays (LCD), field emission displays (FED), plasma displays (PD), electronic Electroluminescent displays (ELD), organic light emitting diode (OLED) displays, micro-LEDs or the like. Aluminoborosilicate glass is used for the protection of electronic devices with display screens, such as mobile phones, entertainment devices, tablets, laptops, digital cameras, wearable devices, or the like.

While exemplary embodiments have been described for purposes of illustration, the foregoing description should not be construed as limiting the scope of the invention or the appended claims. Therefore, various modifications, adaptations and substitutions may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (6)

A chemically strengthened glass article comprising: SiO ₂ in the range of about 40 wt % to about 70 wt %; Al ₂ O ₃ in the range of about 5 wt % to about 35 wt %; about 0.5 wt % to about 10 wt % B ₂ O ₃ in the range; Na ₂ O in the range of about 5 to about 25 wt %; K ₂ O in the range of about 0 to about 5 wt %; and in the range of about 0 to about 7 wt % MgO within the range; P ₂ O ₅ within the range of about 0 wt % to about 10 wt %; ZrO ₂ within the range of about 0 wt % to about 6 wt %; SnO ₂ within the range of about 0 wt % to about 2 wt % ; Fe ₂ O ₃ in the range of about 0 wt % to about 3 wt %; CeO ₂ in the range of about 0 wt % to about 3 wt %; and TiO ₂ in the range of about 0 wt % to about 5 wt %, wherein The glass object undergoes a dual ion exchange process to achieve a K+/Na+ ion ratio greater than 90%, and the glass object has a compression layer depth greater than 50 μm. Such as the chemically strengthened glass object of claim 1, wherein the content of SiO ₂ is optimized to achieve a thermal expansion coefficient compatible with surrounding materials. A method of treating a glass object, comprising the following steps: a) providing a molten salt bath to the glass object containing K+ ions and Na+ ions; b) maintaining a K+/Na+ ion ratio in the molten salt bath higher than that in the glass K+/Na+ ion ratio; c) replace the alkali metal ions Na+ on the glass surface with alkali metal ions K+ in the molten salt bath; d) enrich the surface of the glass object with K+ ions; e) add at least one selected from Alkali metal salts of the group consisting of NaNO ₃ or KNO ₃ ; f) Replace Na+ ions in the surface layer of the glass with K+ ions; g) Maintain the K+/Na+ ion ratio in the glass and the K+/Na+ in the molten salt bath The Na+ ratios are equal; h) blending the alkali metal salts _KNO with _NaNO to provide a liquid ion exchange bath; i) replacing Na+ ions with K+ ions in the surface layer of the glass; and j) maintaining greater than 90% K+ /Na+ ion ratio, wherein the resulting glass object has a compression depth greater than 50 μm. The method of claim 3, wherein the ion exchange time in step (a) is at least 1 hour. The method of claim 3, wherein the ion exchange time in step (h) is less than 60 minutes. The method of claim 3, wherein the dual ion exchange process provides increased scratch resistance to the glass object.