KR20230136870A - Glass composition, glass article prepared therefrom and display device - Google Patents

Abstract

Glass compositions, glass articles made therefrom, and display devices are provided. The glass product has a glass composition of 60 to 70 mol% SiO ₂ , 5 to 15 mol% Al ₂ O _3, 5 to 15 mol% Na ₂ O, 5 to 15 mol% Li ₂ O, 0 to 5 mol% MgO, and ZrO. ₂ It contains 0 to 5 mol%, satisfies Relation 1, and has a thickness in the range of 20 to 100㎛.

Description

Glass composition, glass products manufactured therefrom and display devices {GLASS COMPOSITION, GLASS ARTICLE PREPARED THEREFROM AND DISPLAY DEVICE}

The present invention relates to glass compositions, glass articles made therefrom, and display devices.

Glass products are widely used in electronic devices including display devices and building materials. For example, glass products such as substrates or cover windows that protect flat display devices such as liquid crystal display devices (LCD), organic light emitting display devices (OLED), and electrophoretic displays. This applies.

As the number of portable electronic devices such as smartphones and tablet PCs increases, glass products used in them are frequently exposed to external shocks. For portability, there is a need to develop glass products that are thin and can withstand external shocks.

Recently, foldable display devices are being researched for user convenience. It is desirable for glass products applied to a foldable display device to have a thin thickness to relieve bending stress when folded and at the same time have the strength to withstand external impacts. Accordingly, there are attempts to improve the strength of thin glass products by changing the component ratio of the composition of the glass product and the manufacturing process conditions.

The problem to be solved by the present invention is to provide a glass composition having a novel composition ratio, a glass product manufactured therefrom, and a display device including the glass product.

The problems of the present invention are not limited to the problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

A glass product according to an embodiment for solving the above problem has a glass composition of 60 to 70 mol% SiO ₂ , 5 to 15 mol% Al ₂ O ₃ , 5 to 15 mol% Na ₂ O 5 to 15 mol%, and Li ₂ O 5 relative to the total weight. to 15%, MgO 0 to 5 mol%, and ZrO ₂ 0 to 5 mol%, satisfies the following relational equation 1, and may have a thickness in the range of 20 to 100㎛.

[Relationship 1]

0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio)≤ 1

(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.)

The glass composition may further include 0 to 5 mol% of P ₂ O ₅ .

The glass product may have an etch rate (ER) for a fluorine-based etchant in the range of 1 to 4 μm/min.

The glass product may have a glass transition temperature ranging from 500°C to 700°C.

The glass product may have a density ranging from 2.4 g/cm ³ to 2.5 g/cm ³ .

The glass product may have an elastic modulus ranging from 75 GPa to 85 GPa.

The glass product may have a hardness ranging from 6.0 GPa to 7.0 GPa.

The glass product may have a fracture toughness ranging from 1.0 MPa*m ^0.5 to 1.5 MPa*m ^0.5 .

The glass product may have a brittleness ranging from 4.5㎛ ^-0.5 to 6㎛ ^-0.5 .

The glass product may have a coefficient of thermal expansion ranging from 70*10 ^-7 K ^-1 to 85*10 ^-7 K ^-1 .

The glass product may have a Poison ratio ranging from 0.18 to 0.22.

The average drop height of the pen drop breakage limit for the glass product may be 4.5 cm or more.

In addition, the glass composition according to one embodiment contains 60 to 70 mol% of SiO ₂ , 5 to 15 mol% of Al ₂ O _3, 5 to 15 mol% of Na ₂ O, 5 to 15% of Li ₂ O, and 0 to 5 mol of MgO, based on the total weight. % and 0 to 5 mol% of ZrO ₂ , and may satisfy the following relational equation 1.

[Relationship 1]

0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1

(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.)

The glass composition may further include 0 to 5 mol% of P ₂ O ₅ .

The glass composition may not contain R ₂ O (R=K) except for Na ₂ O and Li ₂ O.

In addition, the display device according to one embodiment includes a display panel including a plurality of pixels, a cover window disposed on an upper portion of the display panel, and an optically transparent bonding layer disposed between the display panel and the cover window, The cover window is a glass composition of 60 to 70 mol% SiO ₂ , 5 to 15 mol% Al ₂ O _3, 5 to 15 mol% Na ₂ O, 5 to 15 mol% Li ₂ O, 0 to 5 mol% MgO, and ZrO, based on the total weight. ₂ 0 to 5 mol%, the cover window satisfies the following relational equation 1, and may have a thickness in the range of 20 to 100 ㎛.

[Relationship 1]

0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1

(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.)

The cover window may further include 0 to 5 mol% of P ₂ O ₅ .

The cover window may not include R ₂ O (R=K) except for Na ₂ O and Li ₂ O.

The cover window may have a glass transition temperature ranging from 500°C to 700°C.

The cover window may have a density ranging from 2.4 g/cm ³ to 2.5 g/cm ³ .

The cover window may have an elastic modulus in the range of 75 GPa to 85 GPa.

The cover window may have a hardness ranging from 6.0 GPa to 7.0 GPa.

The cover window may have a fracture toughness ranging from 1.0 MPa*m ^0.5 to 1.5 MPa*m ^0.5 .

The cover window may have a brittleness ranging from 4.5㎛ ^-0.5 to 6㎛ ^-0.5 .

The cover window may have a thermal expansion coefficient ranging from 70*10 ^-7 K ^-1 to 85*10 ^-7 K ^-1 .

The cover window may have a Poison ratio ranging from 0.18 to 0.22.

Specific details of other embodiments are included in the detailed description and drawings.

The glass composition according to one embodiment may include a novel composition ratio of each component, and a glass product manufactured therefrom may have flexibility and excellent mechanical strength, surface strength, and impact resistance properties. In particular, glass products can have excellent processability and can have excellent flexibility and strength enough to be applied to foldable display devices.

Effects according to the embodiments are not limited to the contents exemplified above, and further various effects are included in the present specification.

1 is perspective views of glass products according to various embodiments.
Figure 2 is a perspective view showing a display device to which a glass product according to one embodiment is applied in an unfolded state.
FIG. 3 is a perspective view showing the display device of FIG. 2 in a folded state.
Figure 4 is a cross-sectional view showing an example in which a glass product according to an embodiment is applied as a cover window of a display device.
Figure 5 is a cross-sectional view of a flat plate-shaped glass product according to one embodiment.
Figure 6 is a graph showing the stress profile of a glass product according to one embodiment.
Figure 7 is a step-by-step flowchart of the manufacturing process of a glass product according to an embodiment.
Figure 8 is a schematic diagram schematically showing the surface polishing stage after strengthening from the cutting stage of Figure 7.
Figure 9 is a graph showing the results of a pen drop test for evaluating the impact resistance characteristics of a glass product according to an embodiment.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

When an element or layer is referred to as “on” another element or layer, it includes instances where the element or layer is directly on top of or intervening with the other element. Like reference numerals refer to like elements throughout the specification. The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining the embodiments are illustrative and the present invention is not limited to the details shown.

Although first, second, etc. are used to describe various components, these components are of course not limited by these terms. These terms are merely used to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be a second component within the technical spirit of the present invention.

Each feature of the various embodiments of the present invention can be combined or combined with each other, partially or entirely, and various technological interconnections and operations are possible, and each embodiment can be implemented independently of each other or together in a related relationship. It may be possible.

Hereinafter, specific embodiments will be described with reference to the attached drawings.

1 is a perspective view of a glass product according to various embodiments.

Glass is used to protect displays in electronic devices including tablet PCs, laptop PCs, smart phones, e-books, televisions, PC monitors, as well as refrigerators and washing machines with display screens, as cover windows, display panel substrates, and touch screens. It is used as a panel substrate and optical members such as light guide plates. Glass can also be used for cover glass such as automobile dashboards, cover glass for solar cells, interior materials for building materials, and windows of buildings and houses.

Glass is required to have high strength. For example, in the case of window glass, it is desirable to have a thin thickness to meet the requirements of high transmittance and light weight, while having a strength that does not easily break due to external impact. Strength-reinforced glass can be manufactured by methods such as chemical strengthening or thermal strengthening. Examples of tempered glass of various shapes are shown in Figure 1.

Referring to Figure 1, in one embodiment, glass article 100 may be in the shape of a flat sheet or flat plate. In other embodiments, the glass articles 101, 102, and 103 may have a three-dimensional shape including curved portions. For example, the edges of the flat portion may be curved (see '101'), generally curved (see '102'), or folded (see '103'). Alternatively, the glass product 100 may have the shape of a flat sheet or flat plate, but may be flexible and folded, stretched, or rolled.

The planar shape of the glass products 100-103 may be rectangular, but is not limited thereto and may have various shapes such as rectangles with rounded corners, squares, circles, and ovals. In the following embodiments, the glass products 100 - 104 are described by taking a flat plate having a rectangular planar shape as an example, but it is clear that the glass products 100 - 104 are not limited thereto.

Figure 2 is a perspective view showing a display device to which a glass product according to one embodiment is applied in an unfolded state. FIG. 3 is a perspective view showing the display device of FIG. 2 in a folded state.

Referring to FIGS. 2 and 3 , the display device 500 according to one embodiment may be a foldable display device. As will be described later, the display device 500 may use the glass product 100 of FIG. 1 as a cover window, and the glass product 100 may be flexible and foldable.

2 and 3 , the first direction DR1 may be a direction parallel to one side of the display device 500 when viewed on a plane, for example, the horizontal direction of the display device 500. The second direction DR2 is a direction parallel to the other side that is in contact with one side of the display device 500 when viewed on a plane, and may be the vertical direction of the display device 500. The third direction DR3 may be a thickness direction of the display device 500.

In one embodiment, the display device 500 may have a rectangular shape when viewed on a plane. When viewed on a plane, the display device 500 may have a rectangular shape with vertical corners or a rectangular shape with rounded corners. When viewed on a plane, the display device 500 may include two short sides arranged in the first direction DR1 and two long sides arranged in the second direction DR2.

The display device 500 includes a display area (DA) and a non-display area (NDA). When viewed on a plane, the shape of the display area DA may correspond to the shape of the display device 500. For example, if the display device 500 is rectangular when viewed on a plane, the display area DA may also be rectangular.

The display area DA may be an area that displays an image including a plurality of pixels. A plurality of pixels may be arranged in a matrix direction. The plurality of pixels may have a rectangular, diamond, or square shape when viewed on a plane, but is not limited thereto. For example, when viewed on a plane, the plurality of pixels may be rectangular, diamond, or other squares, polygons other than squares, circular, or oval.

The non-display area (NDA) may be an area that does not display an image because it does not contain pixels. The non-display area NDA may be placed around the display area DA. The non-display area NDA may be arranged to surround the display area DA, but is not limited to this. The display area DA may be partially surrounded by the non-display area NDA.

In one embodiment, the display device 500 can maintain both a folded state and an unfolded state. The display device 500 may be folded using an in-folding method in which the display area DA is disposed on the inside, as shown in FIG. 3 . When the display device 500 is folded using the in-folding method, the top surfaces of the display device 500 may be arranged to face each other. As another example, the display device 500 may be folded using an out-folding method in which the display area DA is disposed on the outside. When the display device 500 is folded using an out-folding method, lower surfaces of the display device 500 may be arranged to face each other.

In one embodiment, the display device 500 may be a foldable device. In this specification, a foldable device is a device that can be folded, and is used to include not only a folded device, but also a device that can have both a folded state and an unfolded state. In addition, folding typically includes, but is not limited to, folding at an angle of about 180°, and when the folding angle exceeds or falls short of 180°, for example, 90° or more but less than 180° or 120° or more but less than 180°. Even when it is bent at an angle, it can be understood as folded. In addition, the folded state may be referred to as a folded state when it is in a bent state beyond the unfolded state, even if complete folding is not achieved. For example, even if it is bent at an angle of 90° or less, it can be expressed as being in a folded state to distinguish it from an unfolded state as long as the maximum folding angle is 90° or more. The radius of curvature when folded may be 5 mm or less, preferably in the range of 1 mm to 2 mm, or about 1.5 mm, but is not limited thereto.

In one embodiment, the display device 500 may include a folding area (FDA), a first non-folding area (NFA1), and a second non-folding area (NFA2). The folding area FDA may be an area where the display device 500 is folded, and the first non-folding area NFA1 and the second non-folding area NFA2 may be areas where the display device 500 is not folded.

The first non-folding area NFA1 may be disposed on one side, for example, on the upper side of the folding area FDA. The second non-folding area NFA2 may be disposed on the other side of the folding area FDA, for example, on the lower side. The folding area FDA may be an area bent with a predetermined curvature.

In one embodiment, the folding area (FDA) of the display device 500 may be set at a specific location. In the display device 500, there may be one folding area (FDA) determined at a specific location, or there may be two or more. In another embodiment, the location of the folding area FDA is not specified in the display device 500 and may be freely set in various areas.

In one embodiment, the display device 500 may be folded in the second direction DR2. Because of this, the length of the display device 500 in the second direction DR2 can be reduced by approximately half, making it convenient for the user to carry the display device 500.

In one embodiment, the direction in which the display device 500 is folded is not limited to the second direction DR2. For example, the display device 500 may be folded in the first direction DR1. In this case, the length of the display device 500 in the first direction DR1 may be reduced by approximately half.

In the drawing, the display area (DA) and the non-display area (NDA) each overlap the folding area (FDA), the first non-folding area (NFA1), and the second non-folding area (NFA2), but are not limited to this. No. For example, each of the display area DA and the non-display area NDA may overlap at least one of the folding area FDA, the first non-folding area NFA1, and the second non-folding area NFA2. .

Figure 4 is a cross-sectional view showing an example in which a glass product according to an embodiment is applied as a cover window of a display device.

Referring to FIG. 4, the display device 500 includes a display panel 200, a glass product 100 disposed on the display panel 200 and serving as a cover window, the display panel 200, and the glass product 100. It may include an optically transparent bonding layer 300 disposed between the display panel 200 and the glass product 100.

The display panel 200 includes, for example, an organic light emitting display panel (OLED), an inorganic light emitting display panel (inorganic EL), a quantum dot light emitting display panel (QED), a micro LED display panel (micro-LED), and a nano LED display panel. Self-luminous display panels such as (nano-LED), plasma display panel (PDP), field emission display panel (FED), and cathode ray display panel (CRT), as well as liquid crystal display panel (LCD) and electrophoretic display panel (EPD) It may include a light-receiving display panel, etc.

The display panel 200 includes a plurality of pixels (PX) and can display an image using light emitted from each pixel (PX). The display device 500 may further include a touch member (not shown). In one embodiment, the touch member may be internalized in the display panel 200. For example, the display panel 200 itself can perform a touch function by forming a touch member directly on the display member of the display panel 200. In another embodiment, the touch member may be manufactured separately from the display panel 200 and then attached to the top surface of the display panel 200 by an optically transparent bonding layer.

A glass product 100 that protects the display panel 200 is disposed on the top of the display panel 200. The glass product 100 may be larger than the display panel 200 and its side may protrude outward from the side of the display panel 200, but the glass product 100 is not limited thereto. The display device 500 may further include a printing layer (not shown) disposed on at least one surface of the glass product 100 at an edge portion of the glass product 100 . The printed layer prevents the bezel area of the display device 500 from being visible to the outside, and may perform a decorative function in some cases.

An optically transparent bonding layer 300 is disposed between the display panel 200 and the glass product 100. The optically transparent bonding layer 300 serves to fix the glass product 100 on the display panel 200. The optically transparent bonding layer 300 may include an optically clear adhesive (OCA) or an optically clear resin (OCR).

Hereinafter, the above-described strengthened glass product 100 will be described in more detail.

Figure 5 is a cross-sectional view of a flat plate-shaped glass product according to one embodiment.

Referring to FIG. 5 , the glass product 100 may include a first surface (US), a second surface (RS), and a side surface. In the flat plate-shaped glass product 100, the first surface (US) and the second surface (RS) are main surfaces with a large area, and the side surface connects the first surface (US) and the second surface (RS). becomes the outer surface.

The first surface US and the second surface RS face each other in the thickness direction. When the glass product 100 serves to transmit light, such as a cover window of a display, light may mainly enter one of the first surface (US) and the second surface (RS) and transmit through the other.

The thickness (t) of the glass article 100 is defined as the distance between the first surface (US) and the second surface (RS). The thickness (t) of the glass product 100 is not limited thereto, but may range from 20 μm to 100 μm. In one embodiment, the thickness (t) of the glass article 100 may be 80 μm or less. In other embodiments, the thickness t of glass article 100 may be about 75 μm or less. In another embodiment, the thickness t of the glass article 100 may be about 70 μm or less. In another embodiment, the thickness t of the glass article 100 may be about 60 μm or less. In another embodiment, the thickness t of the glass article 100 may be about 65 μm or less. In another embodiment, the thickness t of the glass article 100 may be about 50 μm or less. In another embodiment, the thickness t of the glass article 100 may be about 30 μm or less. In some specific embodiments, the thickness t of the glass article 100 may range from 20 μm to 50 μm, or may have a value around 30 μm. The glass product 100 may have a uniform thickness t, but is not limited thereto and may have different thicknesses t for each region.

Glass article 100 may be strengthened to have a predetermined stress profile therein. The strengthened glass product 100 prevents cracks from occurring, propagating cracks, and breaking due to external shock better than the glass product 100 before strengthening. The glass product 100 strengthened through the strengthening process may have various stresses in each region. For example, near the surface of the glass product 100, that is, near the first surface (US) and the second surface (RS), compression regions (CSR1, CSR2) where compressive stress acts are formed, and the inside of the glass product 100 A tensile region (CTR) where tensile stress acts may be disposed. The boundary (DOC1, DOC2) between the compression region (CSR1, CSR2) and the tension region (CTR) may have a stress value of 0. The compressive stress within one compression region (CSR1, CSR2) may vary depending on the location (i.e., depth from the surface). Additionally, the tensile region (CTR) may have different stress values depending on the depth from the surface (US, RS).

The location of the compression regions (CSR1, CSR2) within the glass article 100, the stress profile within the compression regions (CSR1, CSR2), the compressive energy of the compression regions (CSR1, CSR2) or the tensile energy of the tensile region (CTR), etc. are determined by determining the surface It can have a significant impact on the mechanical properties of the glass product 100, such as strength.

Figure 6 is a graph showing the stress profile of a glass product according to one embodiment. In the graph of Figure 6, the x-axis represents the thickness direction of the glass product. In Figure 6, compressive stress is shown as a positive value and tensile stress is shown as a negative value. In this specification, the magnitude of compressive/tensile stress refers to the magnitude of the absolute value regardless of the sign of the value.

6, the glass article 100 has a first compression region (CSR1) extending (or extending) from the first surface (US) to a first compression depth (DOC1) and a second compression region (CSR1) extending from the second surface (RS) to the first compression depth (DOC1). It includes a second compression region (CSR2) extending (or expanding) to the compression depth (DOC2). A tension region CTR is disposed between the first compression depth DOC1 and the second compression depth DOC2. The overall stress profile within the glass product 100 may have a relationship in which regions on both surfaces (US, RS) are symmetrical with respect to the center of the thickness (t) direction. Although not shown in FIG. 6 , compression and tension zones may be disposed in a similar manner between opposing sides of glass article 100 .

The first compression region (CSR1) and the second compression region (CSR2) serve to prevent the glass product 100 from cracking or being damaged by resisting external impact. As the maximum compressive stresses (CS1, CS2) of the first compression region (CSR1) and the second compression region (CSR2) increase, the strength of the glass product 100 generally increases. Since external shock is usually transmitted through the surface of the glass product 100, it is advantageous in terms of durability to have the maximum compressive stress (CS1, CS2) on the surface of the glass product 100. From this perspective, the compressive stress in the first compression region (CSR1) and the second compression region (CSR2) is greatest at the surface and tends to generally decrease toward the inside.

The first compression depth (DOC1) and the second compression depth (DOC2) are the cracks or grooves formed on the first surface (US) and the second surface (RS) propagating to the tension region (CTR) inside the glass product 100. prevent it from happening The larger the first compression depth (DOC1) and the second compression depth (DOC2), the better the ability to prevent the propagation of cracks, etc. The points corresponding to the first compression depth (DOC1) and the second compression depth (DOC2) correspond to the boundary between the compression regions (CSR1, CSR2) and the tension region (CTR), and the stress value thereof is 0.

Throughout the glass article 100, the tensile stress in the tensile region (CTR) may be balanced with the compressive stress in the compression region (CSR1, CSR2). That is, the sum of compressive stresses (i.e., compressive energy) and the sum of tensile stresses (i.e., tensile energy) within the glass product 100 may be the same. The stress energy accumulated in a region having a constant width in the thickness t direction within the glass product 100 may be calculated as an integral of the stress profile. When the stress profile within the glass product 100 with a thickness t is expressed as a function f(x), the equation below can be established.

[Equation 1]

The larger the internal tensile stress of the glass product 100 is, the more likely it is that when the glass product 100 is broken, fragments will be released violently and shattering will occur from the inside of the glass product 100. The maximum tensile stress that satisfies the fragility standard for the glass product 100 is not limited thereto, but may satisfy the equation below.

[Equation 2]

In some embodiments, the maximum tensile force (CT1) may be less than or equal to 100 MPa, or less than or equal to 85 MPa. Meanwhile, a maximum tensile force (CT1) of 75 MPa or more may be desirable to improve mechanical properties such as strength. In one embodiment, the maximum tensile force (CT1) may be 75 MPa or more and 85 MPa or less, but is not limited thereto.

The maximum tensile stress (CT1) of the glass product 100 may be generally located at the center of the glass product 100 in the thickness t direction. For example, the maximum tensile stress (CT1) of the glass article 100 may be located at a depth ranging from 0.4 t to 0.6 t, or at a depth ranging from 0.45 t to 0.55 t, or at a depth of about 0.5 t.

Meanwhile, in order to increase the strength of the glass product 100, it is desirable for the compressive stress and compression depth (DOC1, DOC2) to be large, but as the compressive energy increases, the tensile energy also increases and the maximum tensile stress (CT1) may also increase. In order to meet the fragility criteria while having high strength, it is desirable to adjust the stress profile so that the maximum compressive stress (CS1, CS2) and compression depth (DOC1, DOC2) are large and the compression energy is low. To this end, the glass product 100 may be manufactured using a glass composition containing specific ingredients in a set amount. Depending on the composition ratio of the components included in the glass composition, the manufactured glass product 100 can have excellent strength and at the same time have flexible properties and physical properties so that it can be applied to a foldable display device.

According to one embodiment, the glass composition forming the glass product 100 contains 60 to 70 mol% of SiO ₂ , 5 to 15 mol% of Al ₂ O ₃ , and 5 to 15 mol% of Na ₂ O, based on the total weight of the glass composition. It may contain Li ₂ O in an amount of 5 to 15%, MgO in an amount of 0 to 5 mol%, and ZrO ₂ in an amount of 0 to 5 mol%. Here, “content of 0 mol%” means substantially no content of the component. The fact that a composition "substantially does not contain" a specific ingredient means that it is not intentionally included in the raw materials, etc., and includes cases where a trace amount of impurities such as 0.1 mol% or less is unavoidably contained, for example.

Each component of the glass composition is described in more detail as follows.

SiO ₂ constitutes the skeleton of glass and can play a role in increasing chemical durability and reducing the occurrence of cracks when scratches (indentations) occur on the glass surface. SiO ₂ may be a network former oxide that forms a network of glass, and the glass product 100 manufactured including SiO ₂ may have a reduced coefficient of thermal expansion and improved mechanical strength. In order to sufficiently perform the above role, SiO ₂ may be included in an amount of 60 mol% or more. In order to exhibit sufficient meltability, the SiO ₂ content in the glass composition may be 70 mol% or less.

Al ₂ O ₃ plays a role in improving the crushability of glass. In other words, Al ₂ O ₃ can play a role in generating a smaller number of fragments when glass breaks. Al ₂ O ₃ may be an intermediate oxide that forms a bond with SiO ₂ to form a network structure. In addition, Al ₂ O ₃ can serve as an active ingredient that improves ion exchange performance during chemical strengthening and increases surface compressive stress after strengthening. When the Al ₂ O ₃ content is 5 mol% or more, the above functions can be effectively performed. Meanwhile, in order to maintain the acid resistance and meltability of glass, it is preferable that the Al ₂ O ₃ content is 15 mol% or less.

Na ₂ O forms surface compressive stress through ion exchange and plays a role in improving the meltability of glass. Na ₂ O can form non-crosslinked oxygen within the SiO ₂ network structure by forming an ionic bond with the oxygen of SiO ₂ forming the network structure. An increase in non-crosslinking oxygen can improve the flexibility of the network structure, and the glass product 100 can have physical properties that can be applied to a foldable display device. It is desirable for Na ₂ O to have a content of 5 mol% or more to effectively perform the above roles. However, from the viewpoint of acid resistance of the glass product 100, it may be desirable to have a content of 15 mol% or less.

Li ₂ O, similar to the above-described Na ₂ O, forms surface compressive stress through ion exchange and plays a role in improving the meltability of glass. Li ₂ O can form non-crosslinked oxygen within the SiO ₂ network structure by forming an ionic bond with the oxygen of SiO ₂ forming the network structure. An increase in non-crosslinked oxygen can improve the flexibility and shock absorption function of the mesh structure, and the glass product 100 can have physical properties that can be applied to a foldable display device. It is desirable for Li ₂ O to have a content of 5 mol% or more to effectively perform the above roles. However, from the viewpoint of heat resistance of the glass product 100, it may be desirable to have a content of 15 mol% or less.

MgO can improve the surface strength of glass and reduce the forming temperature of glass. MgO may be a network modifier oxide that modifies the SiO ₂ network structure forming a network structure. MgO can reduce the refractive index of glass and adjust the thermal expansion coefficient and elastic coefficient of glass. MgO may be omitted (0 mol%), but can perform the above function significantly when contained in an amount of 0.5 mol% or more. However, from the viewpoint of meltability of the glass product 100, it may be desirable to have a content of 5 mol% or less.

ZrO ₂ can improve the transmittance and surface strength of glass and increase resistance to surface crack expansion. ZrO ₂ may be an intermediate oxide that forms a bond with SiO ₂ forming a network structure. ZrO ₂ is bonded to the portion where the bond is broken by Li ₂ O and Na ₂ O in the SiO ₂ network structure, thereby increasing the fracture toughness of the glass and the repulsive force against bending. ZrO ₂ may be omitted (0 mol%), but can perform the above function significantly when contained in an amount of 0.5 mol% or more. However, from the viewpoint of flexibility of the glass product 100, it may be desirable to have a content of 5 mol% or less.

According to one embodiment, the glass composition may satisfy the following relational equation 1.

[Relationship 1]

0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1

(In equation 1 above, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component.)

As described above, the glass product 100 manufactured using the glass composition according to one embodiment may have characteristics and physical properties that can be applied to a foldable display device. For example, the glass product 100 may have flexible properties to enable folding and unfolding, and may have strength and chemical properties sufficient to be applied as a cover window of the display device 500. The network structure formed by the glass composition including SiO ₂ and Al ₂ O ₃ may be formed by adding Na ₂ O and Li ₂ O to form a flexible network structure. By adding Na ₂ O and Li ₂ O, Na ions or Li ions may form ionic bonds with oxygen between bonds forming a network structure, for example, SiO ₂ bonds, thereby increasing non-crosslinked oxygen. An increase in non-bridging oxygen within the network structure means that the bonds in the network structure are broken or open, and the network structure of glass can be flexible. The glass composition may contain Na ₂ O in an amount of 5 mol% or more and Li ₂ O in an amount of 5 mol% or more so that the manufactured glass product 100 has sufficient flexibility.

As the glass composition contains a relatively excessive amount of Na ₂ O and Li ₂ O, it may be weak in mechanical strength. In order to compensate for this, the glass composition includes Al ₂ O ₃ , and the ratio of the sum of the content of Al ₂ O ₃ and the content of Na ₂ O and Li ₂ O is adjusted to the range of 0.3 to 1 according to relational equation 1. Mechanical strength can be added to the mesh structure. According to one embodiment, the glass composition may have a ratio of the sum of the content of Al ₂ O ₃ and the content of Na ₂ O and Li ₂ O, or the R ratio (R ratio) in the range of 0.3 to 1.

The closer the ratio (R ratio) of the sum of the content of Al ₂ O ₃ to the content of Na ₂ O and Li ₂ O contained in the glass composition is 1, the closer Al ₂ O ₃ to the tetrahedral crystal structure formed by SiO ₂ You can have In the network structure formed by SiO ₂ , SiO ₂ may have a tetrahedral crystal structure ([SiO ₄ ]). If the sum of the contents of Na ₂ O and Li ₂ O and Al ₂ O ₃ are included in similar amounts, Al ₂ O It may have a _third- degree tetrahedral crystal structure ([AlO ₄ ]). In this case, the content of non-crosslinked oxygen formed due to the addition of Na ₂ O and Li ₂ O may be reduced, and the ion mobility of the glass composition may be increased. The increase in ion mobility means that the amount of ions moving in the chemical strengthening process in the formation process of the glass product 100 increases and the penetration depth of the ions increases, and the mechanical strength of the surface of the glass product 100 will be improved. You can.

When the ratio (R ratio) of the sum of the content of Al ₂ O ₃ and the content of Na ₂ O and Li ₂ O contained in the glass composition has a value greater than 0.3, the content of Na ₂ O and Li ₂ O increases. The increased Na ₂ O and Li ₂ O can break the network structure of SiO ₂ and increase the distance between atoms in the network structure. Accordingly, a lot of extra space is formed within the network structure of SiO ₂ , and shock absorption characteristics can be improved.

In one embodiment, the ratio (R ratio) of the sum of the content of Al ₂ O ₃ and the content of Na ₂ O and Li ₂ O contained in the glass composition has a value between 0.3 and 1, so that the glass product 100 Flexibility, sufficient strength against external shock, and shock absorption properties can be improved. In an exemplary embodiment, the glass composition includes 66 mol% SiO ₂ , 11.7 mol% Al ₂ O ₃ , 9.2 mol% Na ₂ O, and 9 mol% Li ₂ O, and the R ratio according to Equation 1 above may be 0.64. there is.

In addition to the components listed above, the glass composition may further include components such as Y ₂ O ₃ , La ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Gd ₂ O ₃ if necessary. Additionally, trace amounts of Sb ₂ O ₃ , CeO ₂ , and/or As ₂ O ₃ , etc. may be further included as a fining agent.

Meanwhile, the glass composition may further include P ₂ O ₅ to improve the shock absorption properties of the glass. P ₂ O ₅ improves ion exchange performance and chipping resistance. P ₂ O ₅ may also be a network-forming oxide that forms a network structure together with SiO ₂ . P ₂ O ₅ may have excellent ion mobility by forming a chain structure similar to a polymer, and can absorb shock while changing the positions of atoms during impact. P ₂ O ₅ can perform the above function significantly when it is contained in an amount of 0.5 mol% or more. It may be desirable for P ₂ O ₅ to have a content of 5 mol% or less from the viewpoint of chemical resistance of glass products.

In an exemplary embodiment, when the glass composition includes P ₂ O ₅ , the glass composition contains 63 mol % SiO ₂ , 11.7 mol % Al ₂ O ₃ , 10.6 mol % Na ₂ O, and 7.5 mol % Li ₂ O. %, P ₂ O ₅ and 3 mol%, and the R ratio according to Equation 1 above may be 0.65.

Meanwhile, _the glass composition may not include K ₂ O among R 2 O (R=K) other than Na ₂ O and Li ₂ O to facilitate ion exchange in the chemical strengthening process. In the process of forming the glass product 100, the strengthening process in which ion exchange occurs can be performed only once. The glass composition may not include K ₂ O so that Na ions and Li ions can migrate to the surface of the glass product 100 in large numbers in the chemical strengthening process. The content of R ₂ O, that is, the sum of the Na ₂ O content and the Li ₂ O content, in the total weight of the glass composition is preferably in the range of 15 to 20 mol%.

The glass composition having the above-described composition can be molded into a plate glass shape by various methods known in the art. Once molded into a plate glass shape, it can be further processed to produce a glass product 100 applicable to the display device 500. However, the present invention is not limited thereto, and the glass composition may not be formed into a plate glass shape but may be directly molded into a glass product 100 that can be applied to a product without an additional molding process.

Hereinafter, a process in which a glass composition is molded into a plate glass shape and the glass is processed into a glass product 100 will be described.

Figure 7 is a step-by-step flowchart of the manufacturing process of a glass product according to an embodiment. Figure 8 is a schematic diagram schematically showing the surface polishing stage after strengthening from the cutting stage of Figure 7.

7 and 8, the manufacturing method of the glass product 100 includes a forming step (S1), a cutting step (S2), a side polishing step (S3), a surface polishing step before strengthening (S4), and a strengthening step (S5). ), and a surface polishing step (S6) after strengthening.

The molding step (S1) may include preparing a glass composition and molding the glass composition. The glass composition may have the composition and components as described above. A detailed description of this will be omitted. The glass composition can be molded into a plate glass shape using methods such as float process, fusion draw process, and slot draw process.

Glass molded into a flat plate shape can be cut through a cutting step (S2). Glass molded into a flat plate shape may have a different size than that applied to the final glass product 100. For example, glass molding may be performed using a large-area substrate as the mother substrate 10a including a plurality of glass products, and then cutting it into a plurality of cells 10 to manufacture a plurality of glass products. For example, even if the final glass product 100 has a size of about 6 inches, if the glass is molded to a size several to hundreds of times larger, for example, 120 inches, and then cut, 20 flat plate shapes are formed at once. You can get glass. By doing this, process efficiency can be improved compared to molding individual glass products separately. Additionally, even when molding glass corresponding to the size of one glass product, if the final glass product has various planar shapes, the desired shape can be created through a cutting process.

Cutting of the glass 10a may be performed using a cutting knife 20, a cutting wheel, a laser, etc.

The glass cutting step (S2) may be performed before the glass strengthening step (S5). It is possible to strengthen the glass 10a of the mother substrate unit all at once and then cut it to the final glass product size. However, in this case, the cut side (e.g., the side of the glass) may be left in an unstrengthened state, so the cutting must be completed first. It may be desirable to proceed with the post-strengthening step (S5).

A pre-strengthening polishing step may be performed between the glass cutting step (S2) and the strengthening step (S5). The polishing step may include a side polishing step (S3) and a surface polishing step before strengthening (S4). In one embodiment, the side polishing step (S3) is performed first, followed by the surface polishing step (S4) before strengthening, but this order may be reversed.

The side polishing step (S3) is a step of polishing the side of the cut glass 10. In the side polishing step (S3), the side of the glass 10 is polished to have a smooth surface. Additionally, each side of the glass 10 may have a uniform surface through the side polishing step (S3). More specifically, cut glass 10 may include one or more cut surfaces. Some cut glasses 10 may have two of the four sides cut. Some other cut glasses 10 may have three of the four sides cut. Some other cut glasses 10 may have all four sides cut. When the side is a cut side and when the side is not cut, the surface roughness, etc. may be different. Additionally, the cut surfaces may have different surface roughness. Therefore, by polishing each side through the side polishing step (S3), each side can have uniform surface roughness, etc. Furthermore, if there are small cracks on the side, they can be removed through the side polishing step (S3).

The side polishing step (S3) may be performed simultaneously on a plurality of cut glasses (10). That is, in a state where a plurality of cut glasses 10 are stacked, the laminated glasses 10 can be polished simultaneously.

The side polishing step (S3) may be performed using a mechanical polishing method or a chemical mechanical polishing method using the polishing device 30. In one embodiment, two opposing sides of the cut glass 10 may be polished simultaneously, and then the other two opposing sides may be polished simultaneously, but is not limited to this.

The surface polishing step (S4) before strengthening may be performed to ensure that each glass 10 has a uniform surface. The surface polishing step (S4) before strengthening may be performed one by one for each cut glass 10, but if the chemical mechanical polishing device 40 is sufficiently large compared to the glass 10, a plurality of glasses 10 are arranged horizontally. Afterwards, a plurality of glasses 10 may be surface polished simultaneously.

Surface polishing (S4) before strengthening may be performed using a chemical mechanical polishing method (40). Specifically, the first and second surfaces of the cut glass 10 are polished using the chemical mechanical polishing device 40 and the polishing slurry. The first surface and the second surface may be polished simultaneously, or one surface may be polished first and then the remaining surface may be polished.

After the pre-strengthening polishing step (S4), the strengthening step (S5) proceeds. The strengthening step (S5) may proceed with chemical strengthening and/or thermal strengthening. In the case of glass 10 having a thin thickness of 2 mm or less, and even about 0.75 mm or less, a chemical strengthening method can be appropriately applied to precisely control the stress profile.

After the strengthening step (S5), a post-strengthening surface polishing step (S6) can optionally be further performed. The surface polishing step (S6) after strengthening may serve to remove micro cracks on the surface of the strengthened glass 10 and control the compressive stress of the first and second surfaces of the strengthened glass 10. For example, the floating method, which is one of the methods of manufacturing plate glass, is carried out by pouring a glass composition into a tin bath. In this case, the surface that is in contact with the tin bath and the surface that is not in contact may have different compositions. Accordingly, after the strengthening process (S5) of the glass 10, a deviation in compressive stress may occur between the tin contact surface and the non-contact surface. By removing the surface of the glass 10 to an appropriate thickness by polishing, the compressive stress deviation between the contact surface and the non-contact surface may occur. can be reduced.

The surface polishing process (S6) after strengthening may be performed using a chemical mechanical polishing method. Specifically, the first surface and the second surface of the tempered glass 10, which is the glass to be treated, are polished using the chemical mechanical polishing device 60 and the polishing slurry. The polishing thickness may be adjusted in the range of, for example, 100 nm to 1000 nm, but is not limited thereto. The polishing thickness of the first and second surfaces may be the same, but may also be different.

Although not shown in the drawing, a shape processing process may be further performed as needed after the post-strengthening surface polishing process (S6). For example, when manufacturing the three-dimensional glass products 101-103 shown in FIG. 1, a three-dimensional processing process may be performed after the post-strengthening surface polishing process (S6) is completed.

The glass product 100 manufactured through the above-described process may include a component ratio similar to that of the glass composition. For example, the glass product 100 contains 60 to 70 mol% of SiO ₂ , 5 to 15 mol% of Al ₂ O ₃ , 5 to 15 mol% of Na ₂ O, 5 to 15% of Li ₂ O, and 0 to 15 mol% of MgO. 5 mol% and ZrO ₂ in an amount of 0 to 5 mol%. In addition, the glass product 100 according to another embodiment may include P ₂ O ₅ in an amount of 0 to 5 mol% in addition to the above-described component ratio. The glass composition for manufacturing the glass product 100 may satisfy the following relational expression 1.

[Relationship 1]

0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1

(In equation 1 above, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component.)

Additionally, the glass product 100 according to one embodiment may not include R ₂ O (R=K) other than Na ₂ O and Li ₂ O, for example, K ₂ O.

According to one embodiment, the glass product 100 may have an etch rate in the range of 1㎛/min to 4㎛/min. The glass product 100 has flexibility and strength so that it can be applied to the display device 500, for example, the foldable display device 500, and may have physical properties that facilitate molding as needed. As described above, the glass product 100 manufactured by the glass composition containing Na ₂ O and Li ₂ O may have sufficient mechanical strength to be applied to the foldable display device 500. In addition, the glass product 100 may contain Li ₂ O to improve shock absorption properties, and contain ZrO ₂ to improve surface scratch resistance and crack expansion resistance. In addition, since the glass product 100 has a high etch rate for etchant, the process time required for molding can be reduced, and surface damage due to molding may hardly occur.

In an exemplary embodiment, the glass article 100 may have an etch rate for the etchant ranging from 1 μm/min to 4 μm/min. As an example, an etchant usable for molding the glass product 100 may include a fluorine-based etchant. For example, the etchant may be any one of a hydrogen fluoride (HF)-based etchant, an acidic ammonium fluoride (NH ₄ HF ₂ )-based etchant, and an ammonium bifluoride (NH ₄ F ₂ )-based etchant. Additionally, in some embodiments, the etchant may further include hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), nitroxyl (HNO), ultrapure water, etc. as additives to the fluorine-based etchant.

According to one embodiment, the glass product 100 manufactured from the glass composition described above may have a thickness in the range of 20㎛ to 100㎛ and satisfy the following physical properties.

i) Glass transition temperature (T _g ): 500°C to 700°C

ii) Density: 2.3 g/cm ³ to 2.6 g/cm ³

iii) Elastic modulus: 75GPa to 85GPa

iv) Hardness: 6.0GPa to 7.0GPa

v) Fracture toughness: 1.0 MPa*m ^0.5 to 1.5 MPa*m ^0.5

vi) Brittleness: 4.5㎛ ^-0.5 to 6㎛ ^-0.5

vii) Coefficient of thermal expansion (10 ^-7 K ^-1 ): 70*10 ^-7 K ^-1 to 85*10 ^-7 K ^-1

viii) Poisson ratio: 0.18 to 0.22

Hereinafter, more specific details of the examples are explained through manufacturing examples and experimental examples.

Preparation Example 1: Preparation of glass products

Prepare a plurality of glass substrates with various compositions according to Table 1 below, divide them into SAMPLE #1, SAMPLE #2, SAMPLE #3, SAMPLE #4, SAMPLE #5, and SAMPLE #6, and then follow the method described above for each SAMPLE. The glass product manufacturing process was carried out. The glass product for each sample was manufactured with a thickness of 50㎛.

The composition of the glass products for each sample is shown in Table 1 below. In addition, the density, glass transition temperature, hardness, fracture toughness, brittleness, elastic modulus, thermal expansion coefficient, and Poison ratio of the glass products for each sample were measured and shown in Table 2 below.

sample group SAMPLE#1 SAMPLE#2 SAMPLE #3 SAMPLE #4 SAMPLE #5 SAMPLE #6 Furtherance SiO ₂ 66.0 66.0 63.0 70.0 68.9 67.1 Al ₂ O ₃ 11.7 12.7 11.7 7.7 10.3 11.3 B ₂ O ₃ - - - - - 0.4 MgO 3.1 3.1 3.1 7.5 5.4 4.7 P ₂ O ₅ - - 3.0 - - - Na ₂ O 9.2 10.1 10.6 12.7 15.2 14.8 _K2O - - - 1.7 - 1.4 Li ₂ O 9.0 7.0 7.5 - - - _ZrO2 1.0 1.0 1.0 - - - Composition ratio (mol%) Al ₂ O ₃ :R ₂ O 11.7:18.2 12.7:17.1 11.7:18.1 7.7:14.4 10.3:15.2 11.3:16.2 Composition ratio (mol%) Al ₂ O ₃ /R ₂ O 0.64 0.76 0.65 0.53 0.68 0.70

Properties Density (g/cm ³ ) 2.464 2.446 2.449 2.46 2.42 2.45 Glass transition temperature T _g (℃) 581 610 700 602 599 560 Hardness (GPa) 6.678 6.531 6.531 6.05 5.24 5.79 Fracture toughness (MPa*m ^0.5 ) 1.27 1.29 1.32 0.70 0.68 0.67 Brittleness (㎛ ^-0.5 ) 5.82 5.08 4.99 8.64 7.71 8.64 Elastic modulus (GPa) 85 79 79 74 71.5 70 Coefficient of thermal expansion (10 ^-7 K ^-1 ) 84.0 74.0 84.0 88.0 80.0 91.0 poisson's ratio 0.213 0.202 0.202 0.220 0.210 0.200

Referring to Tables 1 and 2, SAMPLE#1 and SAMPLE#2 are glass products made from a glass composition containing Li ₂ O and ZrO ₂ , respectively, and SAMPLE#3 is a glass product made of a glass composition containing Li ₂ O, ZrO ₂ and P ₂ It is a glass product made from a glass composition containing O ₅ . In addition, SAMPLE #4, #5 and #6 are glass products manufactured from a glass composition that does not contain Li ₂ O, ZrO ₂ and P ₂ O ₅ , respectively. It can be seen that SAMPLE #1, SAMPLE #2 and #3 have a higher hardness of 6.5 GPa or more and an elastic modulus of 79 or more compared to SAMPLE #4, #5 and #6. This can mean that it has excellent flexibility as well as strength. On the other hand, it can be seen that SAMPLE #4, #5, and #6 have relatively low hardness of 6.1 GPa or less and elastic modulus of 74 or less. Through this, it can be seen that SAMPLE #4, #5 and #6 have relatively low strength and flexibility.

In addition, SAMPLE#1, SAMPLE#2, and SAMPLE#3 have fracture toughness of 1.27MPa*m ^0.5 , 1.29 MPa*m ^0.5 , and 1.32MPa*m ^0.5 , respectively, and brittleness of 5.82㎛ ^-0.5 and 5.08㎛ ^-0.5, respectively. , and 4.99㎛ ^-0.5 . On the other hand, considering that SAMPLE#4, #5 and #6 have fracture toughness of 0.7 MPa*m ^0.5 or less and brittleness of 7.7㎛ ^-0.5 or more, SAMPLE#1, SAMPLE#2 and SAMPLE#3 are better than other samples. It can be seen that the impact resistance properties are excellent.

Experimental Example 1: Evaluation of impact resistance characteristics - Pen drop (pen diameter 0.7π) evaluation

Among the samples in Table 1, a pen drop test (PDT) was conducted on SAMPLE#1, SAMPLE#2, and SAMPLE#4. The pen drop experiment was conducted by dropping a pen with a diameter of 0.7π on the surface of a fixed sample product to check the height at which cracks occur on the surface of the product. The drop height of the pen moved by 0.1cm and ranged from 0.5cm to 10cm. When the pen was repeatedly dropped and finally broke, the height just before that (i.e., the maximum height without breakage) was determined as the limit drop height. The results are shown in Figure 9. In particular, SAMPLE#1 was manufactured with different strengthening steps of 20 minutes, 40 minutes, 60 minutes, and 80 minutes during the glass manufacturing process, and then a pen drop experiment was performed, and SAMPLE#2 was manufactured after performing the strengthening step for 20 minutes. A pen drop experiment was conducted.

Figure 9 is a graph showing the results of a pen drop test for evaluating the impact resistance characteristics of a glass product according to an embodiment.

Referring to Figure 9, the average value of the critical drop height of SAMPLE #4 was measured to be 2.32 cm. On the other hand, in the case of SAMPLE #1, when the strengthening stages were varied to 20 minutes, 40 minutes, 60 minutes, and 80 minutes, respectively, the average values of the critical fall height were measured to be 6.57 cm, 6.38 cm, 4.57 cm, and 6.83 cm. In the case of SAMPLE#2, the average value of the critical fall height was measured at 7.7cm.

Through this, it can be seen that SAMPLE#1 and SAMPLE#2 show a much higher average value of the critical drop height in the pen drop test than SAMPLE#4 and have excellent surface strength. The glass product 100 according to one embodiment may have an average limit drop height of 4.5 cm or more as a result of a pen drop test using a pen with a diameter of 0.7π.

Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. You will be able to understand it. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

10: glass 100: glass product
500: display device

Claims (26)

As a glass composition, SiO ₂ 60 to 70 mol%, Al ₂ O ₃ 5 to 15 mol%, Na 2 O 5 to 15 mol%, Li _{2 O} 5 to 15%, MgO 0 to 5 mol% and ZrO ₂ 0 to 15 mol%, based on the total weight. Contains 5 mol%,
A glass product that satisfies the following relational expression 1 and has a thickness in the range of 20 to 100㎛.
[Relationship 1]
0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1
(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.) According to claim 1,
The glass composition further includes 0 to 5 mol% of P ₂ O ₅ . According to claim 1,
A glass product having an etch rate (ER) for a fluorine-based etchant in the range of 1 to 4㎛/min. According to claim 1,
A glass article having a glass transition temperature in the range of 500°C to 700°C. According to claim 1,
Glass articles having a density ranging from 2.4 g/cm ³ to 2.5 g/cm ³ . According to claim 1,
Glass products having an elastic modulus in the range of 75 GPa to 85 GPa. According to claim 1,
Glass products having a hardness ranging from 6.0 GPa to 7.0 GPa. According to claim 1,
A glass product having a fracture toughness ranging from 1.0 MPa*m ^0.5 to 1.5 MPa*m ^0.5 . According to claim 1,
Glass products with brittleness ranging from 4.5㎛ ^-0.5 to 6㎛ ^-0.5 . According to claim 1,
Glass products with a coefficient of thermal expansion ranging from 70*10 ^-7 K ^-1 to 85*10 ^-7 K ^-1 . According to claim 1,
A glass product having a Poison ratio in the range of 0.18 to 0.22. According to claim 1,
Glass products with an average drop height of 4.5 cm or more. Contains 60 to 70 mol% of SiO ₂ , 5 to 15 mol% of Al ₂ O ₃ , 5 to 15 mol% of Na ₂ O, 5 to 15% of Li ₂ O, 0 to 5 mol% of MgO, and 0 to 5 mol% of ZrO ₂ relative to the total weight. do,
A glass composition that satisfies the following relational expression 1.
[Relationship 1]
0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1
(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.) According to claim 13,
A glass composition further comprising 0 to 5 mol% of P ₂ O ₅ . According to claim 13,
A glass composition that does not contain R ₂ O (R=K) except for Na ₂ O and Li ₂ O. A display panel including a plurality of pixels;
a cover window disposed above the display panel; and
Comprising an optically transparent bonding layer disposed between the display panel and the cover window,
The cover window has a glass composition of 60 to 70 mol% SiO ₂ , 5 to 15 mol% Al ₂ O _3, 5 to 15 mol% Na ₂ O, 5 to 15 mol% Li ₂ O, 0 to 5 mol% MgO, and Contains 0 to 5 mol% of ZrO ₂ ,
The cover window satisfies the following relational expression 1 and has a thickness in the range of 20 to 100㎛.
[Relationship 1]
0.3 <Al ₂ O ₃ /(Na ₂ O+Li ₂ O)(R ratio, R ratio) ≤ 1
(Here, Al ₂ O ₃ , Na ₂ O and Li ₂ O are the contents (mol%) of each component in the glass composition.) According to claim 16,
The cover window is a display device further comprising 0 to 5 mol% of P ₂ O ₅ . According to claim 16,
The cover window is a display device that does not include R ₂ O (R=K) except for Na ₂ O and Li ₂ O. According to claim 16,
The cover window is a display device having a glass transition temperature in the range of 500°C to 700°C. According to claim 16,
The cover window is a display device having a density in the range of 2.4g/cm ³ to 2.5g/cm ³ . According to claim 16,
The cover window is a display device having an elastic modulus in the range of 75GPa to 85GPa. According to claim 16,
The cover window is a display device having a hardness in the range of 6.0 GPa to 7.0 GPa. According to claim 16,
The cover window is a display device having a fracture toughness in the range of 1.0MPa*m ^0.5 to 1.5MPa*m ^0.5 . According to claim 16,
The cover window is a display device having a brittleness in the range of 4.5㎛ ^-0.5 to 6㎛ ^-0.5 . According to claim 16,
The cover window is a display device having a thermal expansion coefficient in the range of 70*10 ^-7 K ^-1 to 85*10 ^-7 K ^-1 . According to claim 16,
The cover window is a display device having a Poisson ratio in the range of 0.18 to 0.22.

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