Display glass containing K2O

Abstract

The glass composition includes about 60 mol% to about 80 mol% SiO, 0 mol% to about 11 mol% AlO, about 4.0 mol% to about 12 mol% BO, about 0.5 mol% to about 20 mol% KO, 0 mol% to about 18.5 mol% MgO, and 0 mol% to about 1 mol% SnO, and has a compositionally tunable CTE range and can be used in display applications.

Description

Priority

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 63 / 009,102, filed Apr. 13, 2020, the content of which is relied upon and is hereby incorporated in its entirety by reference.

Technical Field

[0002] The present disclosure relates generally to glass compositions. More particularly, the disclosed subject matter relates to glass compositions that contain alkali metals and are suitable for use in display applications.

Background Art

[0003] Flat or curved substrates made from optically transparent materials such as glass are used in flat panel displays, photovoltaic devices, and other suitable applications. In addition to the requirements for optical transparency, glass compositions need to address different challenges depending on the manufacturing process and the application.

[0004] For example, the manufacture of liquid crystal displays such as active matrix liquid crystal displays (AMLCDs) is complex, and the properties of the substrate glass are important. In the glass substrates used for the manufacture of AMLCDs, it is necessary to strictly control their physical dimensions. The down-draw sheet stretching process and especially the fusion method can produce glass sheets that can be used as substrates without the need for costly post-forming finishing operations such as lapping and polishing. However, the fusion method imposes fairly strict limitations on the glass properties, and for this reason, a relatively high liquid-phase viscosity is required.

[0005] In the field of liquid crystal displays, thin-film transistors (TFTs) can be based on polycrystalline silicon (p-Si) or amorphous silicon (a-Si). Amorphous silicon offers advantages such as lower processing temperatures. Sometimes, polycrystalline silicon is preferred due to its ability to transport electrons more effectively. Polycrystalline silicon transistors are characterized by higher mobility than amorphous silicon transistors. This allows for the manufacture of smaller and faster transistors, ultimately resulting in brighter and faster displays. One problem with p-Si transistors is that their manufacture sometimes requires higher processing temperatures than those used for a-Si transistors. These temperatures range from 450°C to 600°C, compared to the 350°C peak temperature used for a-Si transistors. [Overview of the project] [Problems that the invention aims to solve]

[0006] Glass compositions used in display applications must have good thermal and mechanical properties, and their dimensional stability must meet processing and performance requirements. In addition, diffusion of metal ions into thin-film transistors can damage them. Such diffusion must be minimized or eliminated. [Means for solving the problem]

[0007] This disclosure provides glass compositions containing alkali metals such as potassium, methods for producing the same, and methods for using the same. This disclosure also provides glass substrates made from such glass compositions, and display devices equipped with such glass compositions or glass substrates having such glass compositions.

[0008] According to some embodiments, the glass composition is Approximately 60 mol% to approximately 80 mol% SiO2, Al2O3 ranging from 0 mol% to approximately 11 mol%, Approximately 4.0 mol% to approximately 12 mol% of B2O3, Approximately 0.5 mol% to approximately 20 mol% K2O, MgO from 0 mol% to approximately 18.5 mol%, and SnO2 from 0 mol% to approximately 1 mol%, It becomes practical.

[0009] In this composition, the components are selected from the six types of oxides described above. In some embodiments, K2O is the only alkali metal oxide added, and other alkali metal oxides such as Li2O and Na2O are not included or substantially included. MgO is the only alkaline earth metal oxide added, and CaO, SrO, or BaO are not included or substantially included.

[0010] In the glass composition, SiO2 is present in any suitable range. Examples of suitable ranges include, but are not limited to, about 60 mol% to about 75 mol%, about 65 mol% to about 80 mol%, or about 65 mol% to about 75 mol%. In some embodiments, the SiO2 content is 75 mol% or less, for example, in the range of about 60 mol% to about 75 mol%.

[0011] In some embodiments, the Al2O3 content is 11 mol% or less. Examples of a suitable range for Al2O3 include, but are not limited to, about 0.1 mol% to about 10.5 mol%, about 0.1 mol% to about 2 mol%, about 2 mol% to about 10.5 mol%, about 4 mol% to about 10.5 mol%, or any other suitable range.

[0012] In some embodiments, the alkali metal oxide is K2O having any suitable range of content. Examples of suitable ranges of K2O include, but are not limited to, about 0.5 mol% to about 15 mol%, about 1 mol% to about 15 mol%, about 3.5 mol% to about 15 mol%, about 3 mol% to about 15 mol%, or about 3 mol% to about 10 mol%.

[0013] Examples of appropriate ranges for MgO include, but are not limited to, 0 mol% to about 15 mol%, 0 mol% to about 10 mol%, 0 mol% to about 6 mol%, 0.1 mol% to about 15 mol%, about 0.1 mol% to about 10 mol%, 0.1 mol% to about 0.6 mol%, or about 10 mol% to about 18.5 mol%. In some embodiments, the MgO content is 6 mol% or less, for example, in the range of 0 mol% to about 2 mol%. In some embodiments, the MgO content is 10 mol% or more, for example, in the range of about 10 mol% to about 18.5 mol%, or about 16 mol% to about 18.5 mol%.

[0014] Examples of appropriate ranges for B2O3 include, but are not limited to, approximately 4.9 mol% to 11.5 mol%, approximately 6 mol% to 11 mol%, or approximately 8 mol% to 11 mol%.

[0015] The composition may contain any other suitable component, such as SnO2. Suitable ranges of SnO2 include, but are not limited to, about 0.01 mol% to about 0.5 mol%, or about 0.05 mol% to about 0.15 mol%.

[0016] This disclosure provides any suitable composition having different combinations of the components and content ranges described herein.

[0017] In some embodiments, the molar ratio of K2O / Al2O3 is in the range of about 0.4 to about 360, for example, about 0.4 to about 2, about 1 to about 10, about 1 to about 100, about 100 to about 200, or about 200 to about 360. In some embodiments, the ratio K2O / Al2O3 is in the range of about 1 to about 10, for example, about 0.4 to about 2.

[0018] In some embodiments, the molar ratio of MgO / Al2O3 is in the range of 0 to about 10, for example, 0 to about 4, or 0 to about 1. The molar ratio (k) of SiO2 / B2O3 may be in the range of about 6 to about 15.

[0019] In some embodiments, the R' value defined as ([K2O] - [Al2O3]) / [B2O3] is in the range of about -0.7 to about 0.7, and ([K2O] + 0.5 -7 , -7 , -7 , , -7 , , -7 , , , ,

[0021] , , -7 , -7 , -7 , , , -7 , , -7 , , [MgO] - [Al2O3]) / [B2O3] and the defined R” value is in the range of about -0.3 to about 1.3. [K2O], [MgO], [Al2O3], and [B2O3] represent the molar contents of K2O, MgO, Al2O3, and B2O3, respectively.

[0020] <0​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0022] In some embodiments, the molar ratio (k) of SiO2 / B2O3 may be in the range of about 6 to about 15, the R' value defined as ([K2O]-[Al2O3]) / [B2O3] may be in the range of about -0.7 to about 0.7, and ([K2O]+0.5 * The R'' value, defined as [MgO]-[Al2O3] / [B2O3], ranges from approximately -0.3 to approximately 1.3. [K2O], [MgO], [Al2O3], and [B2O3] represent the molar content of K2O, MgO, Al2O3, and B2O3, respectively.

[0023] In another embodiment, the Disclosure also provides methods for manufacturing and using the glass compositions described herein, glass articles (or components) containing such glass compositions, and display devices containing the glass composition or glass article having the glass composition.

[0024] Examples of glass articles include, but are not limited to, panels, substrates, covers, backplanes, and any other components used in electronic devices for display applications. For example, in some embodiments, the glass composition or glass substrate is a cover or backplane in an electronic device. In some embodiments, thin-film transistors are constructed on or in contact with the glass composition. Examples of electronic devices include, but are not limited to, liquid crystal displays (LCDs), light-emitting diode (LED) displays, computer monitors, automated teller machines (ATMs), touchscreens, and photovoltaic devices. [Brief explanation of the drawing]

[0025] This disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. Following common practice, it should be emphasized that these drawings are for illustrative purposes only of certain embodiments. [Figure 1]Graphs illustrating exemplary relationships between the alkali oxide (e.g., K2O) content and liquidus temperature of exemplary glass compositions according to several embodiments. [Figure 2] Graph showing the relationship between the alkali oxide (e.g., K2O) content and liquid-phase viscosity of exemplary glass compositions according to several embodiments. [Modes for carrying out the invention]

[0026] This description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which should be considered as part of the entire description. In this description, relative terms such as “bottom,” “top,” “horizontal,” “vertical,” “upwards,” “downwards,” “up,” “bottom,” and “bottom,” and their derivatives (e.g., “horizontally,” “downwards,” “upwards,” etc.) should be interpreted as referring to the orientation discussed, described, or shown in the drawings. These relative terms are for explanatory convenience and do not require that the device be constructed or operated in a particular orientation. Terms relating to mounting, linking, etc., such as “connected” and “interconnected,” unless otherwise specified, refer to relationships in which multiple structures are fixed or attached to one another, either directly or indirectly through intervening structures, and to both movable and fixed mountings or relationships.

[0027] For the purposes of the following explanation, it should be understood that the embodiments described below are intended to represent alternative variations and embodiments. It should also be understood that the specific articles, compositions, and / or processes described herein are illustrative and should not be considered limiting.

[0028] In this disclosure, nouns include multiple subjects, and references to specific numerical values ​​include at least that specific value, unless the context clearly indicates otherwise. Where a value is expressed as an approximation using the antecedent “about,” it will be understood that the specific value forms another embodiment. As used herein, “about X” (where X is a numerical value) preferably refers to ±10% (inclusive) of the enumerated value. For example, the phrase “about 8” preferably refers to the value (inclusive) from 7.2 to 8.8. Where present, all ranges are inclusive and combinable. For example, if the range “1 to 5” is enumerated, the enumerated range should be interpreted to include ranges such as “1 to 4,” “1 to 3,” “1 to 2,” “1 to 2 and 4 to 5,” “1 to 3 and 5,” and “2 to 5.” In addition, where a list of options is given positively, such enumeration can be interpreted to mean that any of the options may be excluded, for example, by negative limitations in the claims. For example, if a range of "1 to 5" is enumerated, that enumerated range may be interpreted to include situations in which any of 1, 2, 3, 4, or 5 is negatively excluded; therefore, a quotation of "1 to 5" may be interpreted as "1 and 3-5, but not 2," or simply "2 is not included." Any part, element, attribute, or process positively enumerated herein is intended to be expressly excluded in the claim, whether such part, element, attribute, or process is enumerated as an alternative or whether they are enumerated in isolation.

[0029] The terms “substantial” and “effectively,” as used herein, and their variations thereof, are intended to indicate that the described feature is equal to or nearly equal to a certain value or description. Furthermore, “substantial similar” is intended to indicate that two values ​​are equal to or nearly equal to each other. In some embodiments, “substantial similar” may mean values ​​within approximately 10% of each other, such as within approximately 5% of each other or within approximately 2% of each other.

[0030] This disclosure provides glass compositions containing alkali metal oxides such as potassium, methods for producing the same, and supplementary methods for using the same. This disclosure also provides glass substrates or articles containing such glass compositions, and display devices containing such glass compositions or glass substrates having such glass compositions. Such glass compositions contain components such as those described herein, including low content of Al2O3 and alkali metal oxides such as K2O. In some embodiments, K2O is the only alkali metal oxide in the composition. As described herein, the inventors of this application have unexpectedly found that such glass compositions containing alkali metal oxides and low content of Al2O3 provide low liquidus temperature, high liquidus viscosity, low and tunable coefficient of thermal expansion, and good mechanical properties. The inventors have unexpectedly found that when the glass composition is used in electronic devices, K from the composition is beneficial. + We also found that diffusion of metal ions, such as alkali metal ions, does not occur. Any potential contamination caused by the diffusion of alkali metals with an ionic radius equal to or greater than that of K can be minimized or eliminated.

[0031] Unless the context clearly indicates otherwise, the terms “glass articles” or “glass” as used herein are understood to encompass any articles manufactured whole or in part from glass. Glass articles include monolithic substrates, or laminates of glass and glass, glass and non-glass materials, glass and crystalline materials, and glass and glass ceramics (including amorphous and crystalline phases).

[0032] Glass articles, such as glass panels, may be flat or curved and are transparent or substantially transparent. As used herein, the term “transparent” is intended to indicate that the article, with a thickness of about 1 mm, has a transmittance of more than about 85% in the visible region of the spectrum (400–700 nm). For example, the illustrated transparent glass panel may have a transmittance of more than about 85% in the visible light range, such as more than about 90%, more than about 95%, or more than about 99%, including the entire range and partial ranges in between. According to various embodiments, the glass article may have a transmittance of less than about 50% in the visible region, such as less than about 45%, less than about 40%, less than about 35%, less than about 30%, less than about 25%, or less than about 20%, including the entire range and partial ranges in between. In certain embodiments, the exemplary glass panel may have a transmittance of more than 50% in the ultraviolet (UV) region (100-400 nm), including transmittances of more than 55%, more than 60%, more than 65%, more than 70%, more than 75%, more than 80%, more than 85%, more than 90%, more than 95%, or more than 99%, encompassing the entire range and partial ranges in between.

[0033] Examples of suitable glasses include, but are not limited to, aluminosilicates, alkali aluminosilicates, borosilicates, alkali borosilicates, aluminoborosilicates, alkali aluminoborosilicates, and other suitable glasses. In some embodiments, the glass article may be mechanically strengthened by taking advantage of the mismatch in thermal expansion coefficients between parts of the article to create a central region exhibiting compressive stress and tensile stress. In some embodiments, the glass article may be thermally strengthened by heating the glass to a temperature above its glass transition temperature and then quenching it. In some other embodiments, the glass article may be chemically strengthened by ion exchange.

[0034] In some embodiments, the glass composition described herein is an alkaline earth aluminosilicate glass composition comprising a combination of SiO2, Al2O3, one alkaline earth oxide, and K2O as the sole alkali metal oxide. In some embodiments, MgO is a selected alkaline earth oxide in the glass composition. The glass composition described herein has an amorphous structure. Crystalline or polycrystalline structures can also be produced using this composition.

[0035] The term "softening point" used here refers to the point at which the viscosity of the glass composition reaches 1 × 10⁻⁶. 7.6 This refers to the temperature at which the pore temperature is determined. The softening point is measured using the parallel plate viscosity method.

[0036] The term "annealing point" used here refers to the point at which the viscosity of the glass composition reaches 1 × 10⁻⁶. 13.18 This refers to the temperature at which the poise temperature is reached.

[0037] The terms "distortion point" and "T" used here 歪み The term "glass composition viscosity is 10" refers to a glass composition with a viscosity of 10 14.68 This refers to the temperature at which the poise temperature is reached.

[0038] The liquidus temperature of the glass (T 液相 ) is the temperature (°C) above which the crystalline phase cannot coexist in equilibrium with the glass. Liquidus viscosity is the viscosity of the glass at the liquidus temperature.

[0039] The term "CTE" used here refers to the coefficient of thermal expansion of a glass composition over a temperature range from approximately room temperature (RT) to about 300°C.

[0040] Fracture toughness can be measured using methods known in the art, for example, in accordance with ASTM C1421-10, "Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature," using small square bars with chevron notches, notched beams, etc.

[0041] For the purposes of this disclosure, with respect to mode I crack openings of surface cracks in finite solids, rounded crack tips can be quantified by the decrease in the value describing the defect shape in the following equation relating fracture toughness to fracture stress: K IC =σ f The square root of √{(Ωπα)} Equation (1) During the ceremony, K IC This is the fracture toughness, which is a material constant. σ f This is a measurement of the fracture stress, Ω describes the defect shape, free surface effect, and load configuration. α is the wound depth.

[0042] The average load and fracture stress of the sample were characterized. Furthermore, fracture data and known fracture toughness (m = meter, measured by a chevron notch test) of glass with previously given composition were also described. 0.5 This also includes the value of the square root of (Ωπα) from equation (1) above, calculated from ). As mentioned earlier, in equation (1), the measured fracture stress σ of each glass sample f Fracture toughness of glass (in MPa) IC ( MPa·m 0.5 Corresponds to the ratio of (units). √{(Ωπα)'s square root}(m 0.5The value (in units of ) takes into account both the scratch depth (α) and the scratch "shape" (Ω), so the value directly reflects the effect of the treatment disclosed herein on the scratch shape coefficient, which affects the propagation characteristics of strength-limiting surface scratches that result in stress failure of a surface-scratched glass sheet.

[0043] In the embodiments of the glass compositions described herein, the concentrations of constituent components (e.g., SiO2, Al2O3, etc.) are specified in mole percent (mol%) based on oxides unless otherwise specified.

[0044] The terms "free" and "substantially free" are used to describe the concentration and / or absence of a particular component in a glass composition, meaning that the component has not been intentionally added to the glass composition. However, the glass composition may contain trace amounts of the component as contaminants or tramp in amounts less than 0.01 mol%.

[0045] This disclosure provides glass compositions containing alkali metals such as potassium, methods for producing the same, and methods for using the same. This disclosure also provides glass substrates made from such glass compositions, and display devices equipped with such glass compositions or glass substrates having such glass compositions.

[0046] This disclosure provides a novel glass composition for display glass applications. Based on generally accepted knowledge, alkali metals such as Li2O, Na2O, K2O, Rb2O, and Cs2O are prohibited in display glass compositions because alkalis may diffuse into electronic devices during high-temperature downstream processes, including thin-film transistor (TFT) deposition. The inventors have recently found that oxides of alkali metals with large ionic radii, such as K2O, do not diffuse and can be used in display glass compositions. Diffusion does not occur from the glass substrate into the SiO2 or SiNx barrier layer deposited as a first layer on the glass substrate.

[0047] According to some embodiments, the glass composition is Approximately 60 mol% to approximately 80 mol% SiO2, Al2O3 ranging from 0 mol% to approximately 11 mol%, Approximately 4.0 mol% to approximately 12 mol% of B2O3, Approximately 0.5 mol% to approximately 20 mol% K2O, MgO from 0 mol% to approximately 18.5 mol%, and SnO2 from 0 mol% to approximately 1 mol%, It becomes practical.

[0048] In this composition, the components are selected from the six oxides described above. In some embodiments, only these six oxides are the components. K2O is the only alkali metal oxide added, and does not contain, or substantially contains, other alkali metal oxides such as Li2O and Na2O. MgO is the only alkaline earth metal oxide added, and does not contain, or substantially contains, CaO, SrO, or BaO.

[0049] In the embodiments of the glass composition described herein, SiO2 is the largest component of the composition and, therefore, the main component of the glass network structure.

[0050] In the glass composition, SiO2 is present in any suitable range. Examples of suitable ranges include, but are not limited to, about 60 mol% to about 75 mol%, about 65 mol% to about 80 mol%, or about 65 mol% to about 75 mol%. In some embodiments, the SiO2 content is 75 mol% or less, for example, in the range of about 60 mol% to about 75 mol%.

[0051] The glass compositions described herein may further contain Al2O3 in relatively small amounts, as needed. In some embodiments, the Al2O3 content is 11 mol% or less. Examples of suitable ranges for Al2O3 include, but are not limited to, about 0.1 mol% to about 10.5 mol%, about 0.1 mol% to about 2 mol%, about 2 mol% to about 10.5 mol%, about 4 mol% to about 10.5 mol%, or any other suitable range.

[0052] The glass compositions in the embodiments described herein also include alkali metal oxides. Preferably, the alkali metal oxide is K2O, which is the only alkali metal oxide added. The K2O may be present in any suitable range of content. Examples of suitable ranges of K2O include, but are not limited to, about 0.5 mol% to about 15 mol%, about 1 mol% to about 15 mol%, about 3.5 mol% to about 15 mol%, about 3 mol% to about 15 mol%, or about 3 mol% to about 10 mol%.

[0053] Al2O3, when present, can act in a similar manner to SiO2, and if it is in a tetrahedral coordination in the glass molten formed from the glass composition, it may increase the viscosity of the glass composition. However, as described in U.S. Patent No. 1,0112865, the presence of Al2O3 in a glass composition is thought to increase the mobility of the alkaline components in the glass composition, and the amount of Al2O3 in the glass composition should be carefully considered.

[0054] In the specifications of U.S. Provisional Patent Application No. 62 / 856170, filed on June 3, 2019, and U.S. Provisional Patent Application No. 62 / 886687, filed on August 14, 2019, the inventors unexpectedly found that high content of Al2O3, together with alkali oxides present in the glass composition, reduces the tendency of alkaline components to diffuse or leach from the glass, or maintains alkaline components in the composition under processing conditions in or on a substrate made from the glass composition in which thin-film transistors are formed.

[0055] The inventors of this disclosure have also found, more surprisingly, that zero percent or low content of Al2O3, along with K2O and other components, as disclosed herein, present in glass compositions, reduces the tendency of alkaline components to diffuse or leach from the glass, or maintains alkaline components in the composition under processing conditions under which thin-film transistors are formed in or on substrates made from the glass composition. In addition, glass compositions having alkali oxides such as K2O have relatively low, but controllable thermal expansion. The relevant coefficient of thermal expansion (CTE) can be adjusted or controlled based on the ratio of the components.

[0056] Because the ionic radius of K is relatively large compared to Na and Li, K2O is used as the main alkali oxide component because it reduces the diffusivity of alkali metals in glass. The low diffusivity of alkali metals from glass into overlapping barrier layers is very important when the glass composition is used to form backplanes for displays, because if alkali metals from the glass diffuse into thin-film transistors deposited on the glass, those transistors will be damaged.

[0057] In some embodiments, K2O is a flux used to lower the liquidus temperature and make the glass easier to manufacture. K2O increases the range of the coefficient of thermal expansion (CTE) to include glass compositions with low CTE, medium CTE, and high CTE.

[0058] The glass compositions in the embodiments described herein further include B2O3. B2O3, like SiO2 and Al2O3, contributes to the formation of a glass network structure. In some embodiments, B2O3 may be added to the glass composition to reduce its viscosity. In the embodiments described herein, B2O3 is present in the glass composition in a certain amount. Examples of a suitable range of B2O3 include, but are not limited to, about 4.9 mol% to about 11.5 mol%, about 6 mol% to about 11 mol%, or about 8 mol% to about 11 mol%.

[0059] The compositions provided in this disclosure may optionally contain alkaline earth metal oxides such as MgO. In some embodiments, MgO is the only alkaline earth metal oxide added. Suitable ranges of MgO include, but are not limited to, 0 mol% to about 15 mol%, 0 mol% to about 10 mol%, 0 mol% to about 6 mol%, about 0.1 mol% to about 10 mol%, 0.1 mol% to about 0.6 mol%, or about 10 mol% to about 18.5 mol%. In some embodiments, the MgO content is 6 mol% or less, for example, in the range of 0 mol% to about 2 mol%. In some embodiments, the MgO content is 10 mol% or more, for example, in the range of about 10 mol% to about 18.5 mol%, or about 16 mol% to about 18.5 mol%. MgO has a high electric field strength and is used to increase the elastic modulus of the glass composition.

[0060] The composition may contain any other suitable component, such as SnO2. Suitable ranges of SnO2 include, but are not limited to, about 0.01 mol% to about 0.5 mol%, or about 0.05 mol% to about 0.15 mol%.

[0061] This disclosure provides any suitable composition having different combinations and content ranges of the components described herein.

[0062] In some embodiments, the molar ratio of K2O / Al2O3 is in the range of about 0.4 to about 360, for example, about 0.4 to about 2, about 1 to about 10, about 1 to about 100, about 100 to about 200, or about 200 to about 360. In some embodiments, the ratio K2O / Al2O3 is in the range of about 1 to about 10, for example, about 0.4 to about 2.

[0063] In some embodiments, the molar ratio of MgO / Al2O3 is in the range of 0 to about 10, for example, 0 to about 4, or 0 to about 1. The molar ratio (k) of SiO2 / B2O3 may be in the range of about 6 to about 15.

[0064] In some embodiments, the R' value, defined as ([K2O]-[Al2O3]) / [B2O3], is in the range of approximately -0.7 to approximately 0.7, and ([K2O]+0.5 * The R'' value, defined as [MgO]-[Al2O3] / [B2O3], ranges from approximately -0.3 to approximately 1.3. [K2O], [MgO], [Al2O3], and [B2O3] represent the molar content of K2O, MgO, Al2O3, and B2O3, respectively. The ranges of the R' and R'' values ​​indicate the ratio of alkaline cations to alkaline earth cations remaining after the charge equilibrium of Al2O3 due to the conversion of B2O3 from a planar triangular to a tetragonal crystal. Higher R' and R'' ratios result in more boron present in the glass as IV-coordinate boron, which increases the Young's modulus of the glass composition.

[0065] The glass composition may have properties including a low to moderate Young's modulus, refractive index, density, strain point, annealing point, and softening point. These properties are relevant to and important for display applications.

[0066] In some embodiments, the glass composition is approximately 40 × 10 at a temperature of 20°C to 300°C. -7 From / ℃ to approximately 85 × 10 -7 It has a coefficient of thermal expansion (CTE) in the range of / °C. This CTE can be adjusted for different applications based on the composition. For example, the CTE is approximately 40 × 10⁻⁶.-7 From / ℃ to approximately 80 × 10 -7 / ℃, or approximately 40 × 10 -7 From / ℃ to approximately 70 × 10 -7 / ℃, approx. 40×10 -7 From / ℃ to approximately 60 × 10 -7 / ℃, approx. 30×10 -7 From / ℃ to approximately 40 × 10 -7 / ℃, or approximately 30 × 10 -7 From / ℃ to approximately 50 × 10 -7 It lies within the range of / °C. This range of CTE is convenient for matching the CTE to a wide range of materials, including TFTs at the lower end of the CTE range, and metals such as Ti and alumina at the upper end of the CTE range. Such variations in CTE can be utilized when these glasses are used in laminated structures to create compressive stress due to the mismatch in CTE during cooling.

[0067] This disclosure provides any suitable composition having different combinations and content ranges of the components described herein.

[0068] In some embodiments, the exemplary glass composition is Approximately 60 mol% to approximately 75 mol% SiO2, Approximately 4 mol% to approximately 10.5 mol% Al2O3, Approximately 5 mol% to approximately 11 mol% of B2O3, Approximately 3.5 mol% to approximately 15 mol% K2O, MgO from 0 mol% to approximately 6 mol%, and SnO2 from 0 mol% to approximately 1 mol%, From practically, The molar ratio of K2O / Al2O3 is in the range of approximately 0.4 to 2, and the molar ratio of MgO / Al2O3 is in the range of 0 to 4.

[0069] In some embodiments, the molar ratio (k) of SiO2 / B2O3 may be in the range of about 6 to about 15. The composition has an R' value defined as ([K2O]-[Al2O3]) / [B2O3] in the range of about -0.7 to about 0.7, and ([K2O]+0.5 in the range of about -0.3 to about 1.3.* It has an R'' value defined as [MgO]-[Al2O3] / [B2O3]. [K2O], [MgO], [Al2O3], and [B2O3] represent the molar content of K2O, MgO, Al2O3, and B2O3, respectively.

[0070] The glass composition offers both processing advantages and performance advantages. For example, the glass composition has a low liquidus temperature (T liq ) and high liquidus viscosity. The liquidus temperature may be 1,300°C or less, for example, in the range of about 900°C to about 1,300°C, about 950°C to about 1,300°C, about 1,000°C to about 1,200°C, about 900°C to about 1,185°C, about 1,000°C to about 1,185°C, about 900°C to about 1,150°C, or about 1,000°C to about 1,150°C. In some embodiments, the liquidus temperature is less than 950°C.

[0071] The glass composition has a liquid phase viscosity of 100 kilopoise or more, for example, in the range of about 200 kilopoise to about 400 kilopoise, about 200 kilopoise to about 600 kilopoise, or about 200 kilopoise to about 800 kilopoise. In some embodiments, the liquid phase viscosity may be in the range of about 100 kilopoise to about 800 kilopoise, for example, about 100 kilopoise to about 550 kilopoise, or about 200 kilopoise to about 450 kilopoise.

[0072] The glass compositions disclosed herein have a refractive index at 589.3 nm, ranging from about 1.4 to about 1.6, for example, in the range of about 1.47 to about 1.50. The stress optical coefficient is about 3.2 nm / MPa / cm, for example, 3.253 nm / MPa / cm in some embodiments. The density of this glass composition is about 2.2 g / cm³. 3 Approximately 2.4 g / cm³ 3 For example, approximately 2.249 g / cm³ 3 Approximately 2.393 g / cm³ 3 It is within the range.

[0073] The glass compositions disclosed herein may have a strain point in the range of about 520°C to about 700°C, for example, in the range of about 522°C to about 651°C. The annealing point may be in the range of about 550°C to about 750°C, for example, in the range of about 580°C to about 705°C. The glass compositions may have a softening point in the range of about 800°C to about 1,050°C, for example, in the range of about 835°C to about 1,025°C.

[0074] The glass composition disclosed herein also provides good toughness. The fracture toughness of the glass is K. IC ( MPa·m 0.5 The unit is approximately 0.5 MPa·m 0.5 From approximately 1 MPa·m 0.5 For example, approximately 0.5 MPa·m 0.5 From approximately 0.75 MPa·m 0.5 It may fall within that range.

[0075] The glass composition may have a Poisson's ratio in the range of 0.2 to about 0.3, for example, 0.20 to about 0.23; a Young's modulus in the range of about 50 GPa to about 80 GPa, for example, about 53 GPa to about 73 GPa; and a stiffness modulus in the range of about 20 GPa to about 40 GPa, for example, about 20 GPa to about 30 GPa.

[0076] In another embodiment, the Disclosure also provides methods for manufacturing and using the glass compositions described herein, glass articles (or components) made from such glass compositions, and display devices comprising such glass compositions or glass articles having such glass compositions.

[0077] Examples of glass articles include, but are not limited to, panels, substrates, covers, backplanes, and any other components used in electronic devices for display applications. In some embodiments, glass articles such as substrates or panels are optically transparent. Examples of glass articles include, but are not limited to, flat or curved glass panels.

[0078] For example, in some embodiments, the glass composition or glass substrate is a cover or backplane in an electronic device. In some embodiments, a thin-film transistor is constructed on or in contact with the glass composition. The thin-film transistor may be amorphous silicon-based or polycrystalline silicon-based. In some embodiments, the glass composition provided herein is used as a substrate or layer on which amorphous silicon-based transistors are placed, or on which they are placed. Examples of electronic devices include, but are not limited to, liquid crystal displays (LCDs), light-emitting diode (LED) displays, computer monitors, automated teller machines (ATMs), touchscreens, and photovoltaic devices. [Examples]

[0079] The following examples are described below to illustrate the methods and results according to the disclosed subject matter. These examples are not intended to include all embodiments of the subject matter disclosed herein, but rather to illustrate representative methods and results. These examples are not intended to exclude equivalents and modifications of the disclosure that would be obvious to those skilled in the art.

[0080] While efforts have been made to ensure accuracy in numerical terms (e.g., quantity, temperature), some degree of error and deviation should be considered. Unless otherwise specified, temperature is expressed in °C or as ambient temperature, and pressure is atmospheric pressure or close to atmospheric pressure. The composition itself is given as mole percent on an oxide basis and normalized to 100%. There are many other reaction ranges and condition variations and combinations that can be used to optimize reaction conditions, e.g., component concentrations, temperature, pressure, and the purity and yield of the product obtained from the described process. Optimizing such process conditions requires only reasonable routine experimentation.

[0081] The glass properties described in the table were determined according to conventional techniques in the field of glass technology. Therefore, the coefficient of linear thermal expansion (CTE) over the temperature range of 25 to 300°C is ×10-7 The slewing point is expressed in °C, and the slewing point is expressed in °C. The CTE was determined according to ASTM standard E228. Unless otherwise specified, the slewing point and strain point were determined by beam bending viscosity measurement technique according to ASTM standard C598. g / cm 3 The density expressed as was measured by the Archimedes method (ASTM C693). The melting temperature expressed as °C (defined as the temperature at which the molten glass exhibits a viscosity of 200 poise) was calculated using Fulcher's formula, which was fitted to high-temperature viscosity data measured by the rotary cylinder viscometer (ASTM C965-81).

[0082] The liquidus temperature of the glass, expressed in °C, was measured using the standard gradient boat liquidus method of ASTM C829-81. This method involves placing crushed glass particles in a platinum boat, placing the boat in a furnace with a gradient temperature range, heating the boat within the appropriate temperature range for 24 hours, and determining the highest temperature at which crystals appear inside the glass by microscopic examination. More specifically, the glass sample is removed from the Pt boat in one piece and examined using polarized light microscopy to identify the location and nature of crystals formed at the Pt-air interface and inside the sample. Since the furnace gradient is well known, the temperature-to-position can be accurately estimated within 5–10°C. The temperature at which crystals are observed inside the sample is interpreted as representing the liquidus line of the glass (for the corresponding test period). To observe slower-growing phases, the test is sometimes performed for longer periods (e.g., 72 hours). The liquidus viscosity, expressed in Poise, was determined from the liquidus temperature and the coefficients of Fulcher's equation.

[0083] The Young's modulus and shear modulus values, expressed in GPa, as well as Poisson's ratio, were determined using the general type of resonant ultrasonic spectroscopy technique described in ASTM E1875-00e1.

[0084] The stress-optical coefficient (SOC) can be measured as described in procedure C (glass disk method) of ASTM standard C770-16, titled "Standard Test Method for Measurement of Glass Stress-Optical Coefficient".

[0085] The example glass in the table was prepared using commercially available sand as the silica source and ground so that 90% by mass passed through a standard US 100-mesh sieve. Alumina was the alumina source, periclase was the source of MgO, and tin(IV) oxide was the source of SnO2. The raw materials were thoroughly mixed and double-melted in a crucible. The mixed raw materials were then loaded into a platinum container suspended in a furnace heated with a silicon carbide grover and melted and stirred for several hours at a temperature between 1600°C and 1650°C, and delivered through an opening at the bottom of the platinum container. The mixing and double-melting method ensured homogeneity. The resulting glass putty was annealed at or near the annealing point, and then various experimental methods were used to determine its physical, viscous, and liquid-phase properties.

[0086] These methods are not unique, and the glass compositions can be prepared using standard methods well known to those skilled in the art. Such methods include a continuous melting process in which the melting apparatus used in the continuous melting process is heated by gas, electricity, or a combination thereof.

[0087] Suitable raw materials for manufacturing the exemplary glass include commercially available sand as a source of SiO2; alumina, aluminum hydroxide, hydrated forms of alumina, and various aluminosilicates, nitrates, and halides as sources of Al2O3; boric acid, boric anhydride, and boron oxide as sources of B2O3; and periclase, magnesia, magnesium carbonate, magnesium hydroxide, and various forms of magnesium silicates, aluminosilicates, nitrates, and halides as sources of MgO. If a chemical clarifier is desired, tin may be added as SnO2, as a mixed oxide with another major glass component (e.g., CaSnO3), or in an oxidized state as SnO, tin oxalate, tin halides, or other compounds of tin known in the art.

[0088] The glass composition described above contains SnO2 as a clarifying agent, but other chemical clarifying agents may also be used to obtain glass of sufficient quality for TFT substrate applications.

[0089] In addition to the elements intentionally included in the example glass, almost all stable elements of the periodic table are present in glass to some degree, either due to low levels of contamination in the raw materials, high-temperature corrosion of refractories and precious metals during the manufacturing process, or intentional introduction at low levels to fine-tune the properties of the final glass.

[0090] Hydrogen is the OH group of the hydroxyl anion. -Dissolved hydroxyl ions are inevitably present in this form, and their presence can be confirmed by standard infrared spectroscopy techniques. Dissolved hydroxyl ions have a significant and nonlinear effect on the annealing point of the example glass, and therefore, in order to obtain the desired annealing point, it will be necessary to adjust the concentration of the main oxide component to compensate. The hydroxyl ion concentration can be controlled to some extent by the selection of raw materials or the melting system. For example, boric acid is a major source of hydroxyl, and substituting boric acid with boron oxide may be a useful means of controlling the hydroxyl concentration of the final glass. The same logic applies to other potential materials containing hydroxyl ions, hydrates, or compounds containing physically or chemically adsorbed water molecules. If a burner is used in the melting process, hydroxyl ions can also be introduced by combustion products from the combustion of natural gas and associated hydrocarbons, and therefore, it would be desirable to change the energy used for melting from a burner to electrodes to compensate. Alternatively, an iterative process may be used to adjust the main oxide component to compensate for the harmful effects of dissolved hydroxyl ions.

[0091] Sulfur is often present in natural gas and is also a trump component in the raw materials of many carbonates, nitrates, halides, and oxides. Sulfur, in the form of SO2, can be a troublesome source of gaseous inclusions. The tendency for SO2-rich defects to form can be controlled to a considerable extent by controlling the sulfur levels in the raw materials and by incorporating relatively reduced polyvalent cations at low levels in the glass substrate. Without intending to bind the theory, SO2-rich gaseous inclusions are mainly due to sulfate ions (SO4) dissolved in the glass. = It appears to be produced by the reduction of ).

[0092] Carefully controlling the sulfur level in the raw materials to a low level is a useful means of reducing dissolved sulfur (possibly as sulfate ions) in the glass. In particular, the sulfur level is preferably less than 200 ppm by mass in the batch material, and more preferably less than 100 ppm by mass in the batch material.

[0093] Reduced polyvalent elements can also be used to control the tendency of the example glass to form SO2 blistering. While not intended to bind the theory, these elements act as potential electron donors that suppress the electromotive force for reducing sulfate ions. The reduction of sulfate ions is, SO4 = →SO2+O2+2e - It can be described as a half-reaction such as, in the formula, e - represents electrons. The "equilibrium constant" of this half-reaction is, K eq =[SO2][O2][e - ] 2 / [SO4 = ] In the formula, square brackets indicate chemical activity. Ideally, SO2, O2, and 2e - The goal would be to steer the reaction toward the formation of sulfate ions. Adding nitrates, peroxides, or other oxygen-rich raw materials would be helpful, but would counteract the reduction of sulfate ions in the initial stages of melting. This would diminish the benefit of adding them in the first place. SO2 has very low solubility in most glasses and is therefore difficult to add to the glass melting process. Electrons would be "added" by the reduction of polyvalent elements, for example, ferrous ions (Fe). 2+ The appropriate electron-donating half-reaction for ) is, 2Fe 2+ →2Fe 3+ +2e - It is expressed as follows.

[0094] This "activity" of electrons directs the reduction reaction of sulfate ions to the left, and SO4 in the glass = It can stabilize the following, but is not limited to Fe. 2+ Mn 2+ Sn 2+ Sb 3+ As 3+ , V 3+ Ti 3+Examples include, and other elements familiar to those skilled in the art. In each case, it would be important to minimize the concentration of such components to avoid harmful effects on the color of the glass, or, in the case of As and Sb, to avoid adding such components at levels high enough to complicate waste management in the end-user's process.

[0095] In addition to the main oxide components of the example glass, and the trace or tramp components described above, halides may be present at varying levels, either as contaminants introduced by the selection of raw materials, or as intentional components used to eliminate gaseous inclusions in the glass. Halides may be included as clarifying agents at levels of about 0.4 mol% or less, but it is generally preferable to use them in smaller amounts where possible to avoid corrosion of exhaust gas handling equipment. In some embodiments, the concentration of individual halogen elements is less than about 200 ppm by mass for each individual halogen, or less than about 800 ppm by mass for the sum of all halogen elements.

[0096] Tables 1-4 summarize the composition and properties of 21 experimental samples. Table 1 shows the composition of Experimental Examples 1-5 ("Ex.1-5"). Table 2 shows the composition of Experimental Examples 6-10 ("Ex.6-10"). Table 3 shows the composition of Experimental Examples 11-15 ("Ex.11-15"). Table 4 shows the composition of Experimental Examples 16-21 ("Ex.16-21"). Examples 1-21 are also assigned symbols in the order of "A" to "X". Characteristic data for Examples 1-21, including softening point, annealing point, Young's modulus, shear modulus, and Poisson's ratio, are also listed in Tables 1-4.

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] [Table 4]

[0101] In Table 4, "COV" is the coefficient of variation for fracture toughness data.

[0102] Figure 1 shows the general trend of the effect of K2O content on the liquidus temperature of the compositions disclosed herein. Figure 2 shows the relationship between K2O content and liquidus viscosity as a general trend for the glass compositions disclosed herein. In Figures 1 and 2, experimental samples 1 to 3 ("S1", "S2", and "S3") are compared to a comparative product commercially available from Corning Inc. under the trademark name EAGLE XG ("EXG"), which does not contain K2O. "EAGLE XG" would not contain other comparable components, but is shown here for illustrative purposes only. Product EXG has a liquidus temperature of 1140°C and a liquidus viscosity of 228,527 poise.

[0103] The glass composition has a liquid-phase viscosity of 100 kilopoise or more. For example, the liquid-phase viscosity can be adjusted to a range of about 200 kilopoise to about 400 kilopoise, about 200 kilopoise to about 600 kilopoise, about 100 kilopoise to about 550 kilopoise, or about 200 kilopoise to about 450 kilopoise. Such an increase in liquid-phase viscosity and such a decrease in liquid-phase temperature result in significant processing advantages and reduced manufacturing costs.

[0104] Referring to Tables 1-4, the glass composition has a coefficient of thermal expansion (CTE) within an adjustable range. The example glass has good properties, such as annealing point and Young's modulus, that make it suitable for display applications, such as AMLCD substrate applications, and more specifically, for low-temperature polysilicon and oxide thin-film transistor applications. This glass has durability in acidic and basic media similar to that obtained from commercially available AMLCD substrates, and is therefore suitable for AMLCD applications. The example glass can be formed using down-draw techniques and is particularly suitable for fusion methods.

[0105] Furthermore, despite the significant levels of alkali metal oxides used, when the glass composition is used in electronic devices, metal ions such as alkali metal ions do not leach or diffuse from the composition.

[0106] While the subject matter has been described with respect to the exemplary embodiments, it is not limited thereto. Rather, the accompanying claims should be broadly interpreted to include other variations and embodiments that would be conceivable to those skilled in the art.

[0107] Preferred embodiments of the present invention are described below in separate sections.

[0108] Embodiment 1 Approximately 60 mol% to approximately 80 mol% SiO2, Al2O3 ranging from 0 mol% to approximately 11 mol%, Approximately 4.0 mol% to approximately 12 mol% of B2O3, Approximately 0.5 mol% to approximately 20 mol% K2O, MgO from 0 mol% to approximately 18.5 mol%, and SnO2 from 0 mol% to approximately 1 mol%, A glass composition that is substantially derived from.

[0109] Embodiment 2 The glass composition according to Embodiment 1, wherein the Al2O3 content is in the range of about 0.1 mol% to about 10.5 mol%, 0 mol% to about 2 mol%, about 2 mol% to about 10.5 mol%, or about 4 mol% to about 10.5 mol%.

[0110] Embodiment 3 The glass composition according to Embodiment 1, wherein the K2O content is in the range of about 0.5 mol% to about 15 mol%, about 1 mol% to about 15 mol%, about 3.5 mol% to about 15 mol%, about 3 mol% to about 15 mol%, or about 3 mol% to about 10 mol%.

[0111] Embodiment 4 The glass composition according to Embodiment 1, wherein the SiO2 content is in the range of about 60 mol% to about 75 mol%, about 65 mol% to about 80 mol%, or about 65 mol% to about 75 mol%.

[0112] Embodiment 5 The glass composition according to Embodiment 1, wherein the MgO content is in the range of 0 mol% to about 15 mol%, 0 mol% to about 10 mol%, 0 mol% to about 6 mol%, about 0.1 mol% to about 10 mol%, 0.1 mol% to about 0.6 mol%, or about 10 mol% to about 18.5 mol%.

[0113] Embodiment 6 The glass composition according to Embodiment 1, wherein the B2O3 content is in the range of about 4.9 mol% to about 11.5 mol%, about 6 mol% to about 11 mol%, or about 8 mol% to about 11 mol%.

[0114] Embodiment 7 The glass composition according to Embodiment 1, wherein the SnO2 content is in the range of about 0.01 mol% to about 0.5 mol%, or about 0.05 mol% to about 0.15 mol%.

[0115] Embodiment 8 The glass composition according to Embodiment 1, wherein the molar ratio of K2O / Al2O3 is in the range of about 0.4 to about 360.

[0116] Embodiment 9 The glass composition according to Embodiment 1, wherein the molar ratio of MgO / Al2O3 is in the range of 0 to about 10.

[0117] Embodiment 10 The glass composition according to Embodiment 1, wherein the molar ratio of MgO / Al2O3 is in the range of 0 to about 4.

[0118] Embodiment 11 The glass composition according to Embodiment 1, wherein the molar ratio of SiO2 / B2O3 is in the range of about 6 to about 15.

[0119] Embodiment 12 The R' value, defined as ([K2O]-[Al2O3]) / [B2O3], is in the range of approximately -0.7 to approximately 0.7, and ([K2O]+0.5 * The glass composition according to Embodiment 1, wherein the R'' value, defined as [MgO]-[Al2O3] / [B2O3], is in the range of approximately -0.3 to approximately 1.3, and in the formula, [K2O], [MgO], [Al2O3], and [B2O3] represent the molar content of K2O, MgO, Al2O3, and B2O3, respectively.

[0120] Embodiment 13 The glass composition yields approximately 40 × 10 at temperatures ranging from 20°C to 300°C. -7 From / ℃ to approximately 85 × 10 -7 The glass composition according to Embodiment 1, having a thermal expansion coefficient in the range of / °C.

[0121] Embodiment 14 Approximately 60 mol% to approximately 75 mol% SiO2, Approximately 4 mol% to approximately 10.5 mol% Al2O3, Approximately 5 mol% to approximately 11 mol% of B2O3, Approximately 3.5 mol% to approximately 15 mol% K2O, MgO from 0 mol% to approximately 6 mol%, and SnO2 from 0 mol% to approximately 1 mol%, From practically, A glass composition in which the molar ratio of K2O / Al2O3 is in the range of approximately 0.4 to approximately 2, and the molar ratio of MgO / Al2O3 is in the range of 0 to approximately 4.

[0122] Embodiment 15 The glass composition according to Embodiment 14, wherein the molar ratio (k) of SiO2 / B2O3 is in the range of about 6 to about 15.

[0123] Embodiment 16 The R' value, defined as ([K2O]-[Al2O3]) / [B2O3], is in the range of approximately -0.7 to approximately 0.7, and ([K2O]+0.5 * The glass composition according to Embodiment 14, wherein the R'' value, defined as [MgO]-[Al2O3] / [B2O3], is in the range of approximately -0.3 to approximately 1.3, and in the formula, [K2O], [MgO], [Al2O3], and [B2O3] represent the molar content of K2O, MgO, Al2O3, and B2O3, respectively.

[0124] Embodiment 17 A glass article made from the glass composition described in Embodiment 1.

[0125] Embodiment 18 A display device comprising the glass composition described in Embodiment 1, or a glass substrate made from the glass composition described in Embodiment 1.

[0126] Embodiment 19 The display device according to Embodiment 18, wherein the glass composition or the glass substrate is a cover or backplane in an electronic device for display applications.

[0127] Embodiment 20 A display device comprising the glass composition described in Embodiment 14, or a glass article made from the glass composition described in Embodiment 14.

Claims

1. 60 mol% to 80 mol% SiO ２ , 4 mol% to 10.5 mol% Al ２ O ３ , 4.0 mol% to 12 mol% of B ２ O ３ , 0.5 mol% to 10 mol% K ２ O, MgO in amounts from 0 mol% to 18.5 mol%, and 0 mol% to 1 mol% SnO ２ , A glass composition that is substantially derived from.

2. K ２ The glass composition according to claim 1, wherein the O content is in the range of 3 mol% to 10 mol%.

3. SiO ２ The glass composition according to claim 1, wherein the content of ２ is in the range of 65 mol% to 75 mol%.

4. The glass composition according to claim 1, wherein the MgO content is in the range of 10 mol% to 18.5 mol%.

5. B ２ O ３ The glass composition according to claim 1, wherein the content of is in the range of 8 mol% to 11 mol%.

6. SnO ２ The glass composition according to claim 1, wherein the content of is in the range of 0.05 mol% to 0.15 mol%.

7. K ２ O / Al ２ O ３ The glass composition according to claim 1, wherein the molar ratio of is in the range of 0.4 to 360.

8. MgO / Al ２ O ３ The glass composition according to claim 1, wherein the molar ratio of is in the range of 0 to 4.

9. SiO ２ / B ２ O ３ The glass composition according to claim 1, wherein the molar ratio of is in the range of 6 to 15.

10. ([K ２ O]-[Al ２ O ３ ]) / [B ２ O ３ The R' value, defined as ], is in the range of -0.7 to 0.7, ([K ２ O] + 0.5 ＊ [MgO]-[Al ２ O ３ ]) / [B ２ O ３ The R'' value, defined as ], is in the range of -0.3 to 1.3, and in the formula, [K ２ O], [MgO], [Al ２ O ３ ], and [B ２ O ３ ] are, K ２ O, MgO, Al ２ O ３ , and B ２ O ３ The glass composition according to claim 1, representing the molar content.

11. 60 mol% to 75 mol% SiO ２ , 4 mol% to 10.5 mol% Al ２ O ３ , 5 mol% to 11 mol% of B ２ O ３ , 3.5 mol% to 10 mol% K ２ O, 0 mol% to 6 mol% MgO, and 0 mol% to 1 mol% SnO ２ , From practically, K ２ O / Al ２ O ３ The molar ratio is in the range of 0.4 to 2, MgO / Al ２ O ３ A glass composition in which the molar ratio is in the range of 0 to 4.

12. SiO ２ / B ２ O ３ The glass composition according to claim 11, wherein the molar ratio (k) is in the range of 6 to 15.

13. ([K ２ O]-[Al ２ O ３ ]) / [B ２ O ３ The R' value, defined as ], is in the range of -0.7 to 0.7, ([K ２ O] + 0.5 ＊ [MgO]-[Al ２ O ３ ]) / [B ２ O ３ The R'' value, defined as ], is in the range of -0.3 to 1.3, and in the formula, [K ２ O], [MgO], [Al ２ O ３ ], and [B ２ O ３ ] are, K ２ O, MgO, Al ２ O ３ , and B ２ O ３ The glass composition according to claim 11, representing the molar content.

14. A glass article made from the glass composition according to any one of claims 1 to 13.

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