Glass substrate, glass laminate, display device and electronic device

Abstract

To provide a glass base material and glass laminate, excellent in bending resistance and shock resistance in an end part.SOLUTION: A glass base material has a second surface 1B facing a first surface 1A and a side surface 1C connecting the first surface 1A and the second surface 1B. The thickness of the glass base material is 100 μm or less; the side surface 1C connected to the first surface 1A has an inclined part 2a extended to incline on the side of the second surface 1B to the first surface 1A toward the outside from the end part of the first surface 1A; the width of the inclined part 2a in the first surface 1A direction of the glass base material is 0.05 μm or more and 9.00 μm or less; and the length of the inclined part 2a in the thickness direction of the glass base material is 0.05 μm or more and 5.00 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a glass substrate, a glass laminate using the same, a display device, and an electronic device. [Background technology]

[0002] Conventionally, display devices have used glass or resin cover members to protect the display device. These cover members protect the display device from impacts and scratches, and are required to have strength, impact resistance, scratch resistance, and the like. Glass cover members are characterized by high surface hardness, scratch resistance, and high transparency, while resin cover members are characterized by light weight and shatter resistance. In addition, the thicker the cover member, the better its ability to protect the display device from impacts, and the material and thickness of the cover member are appropriately selected based on the weight, cost, size of the display device, and the like.

[0003] BACKGROUND ART In recent years, flexible displays such as foldable displays, rollable displays, and bendable displays have been actively developed, and among these, development of foldable displays, i.e., display devices that can be bent, has been progressing.

[0004] In bendable display devices, the cover member must also bend in accordance with the movement of the display device, and therefore a bendable cover member is used. In the case of resin cover members, polyimide or polyamide-imide films that have been made colorless and transparent through ingenuity in their chemical structure have been developed (see, for example, Patent Document 1). In the case of glass cover members, studies are underway to develop bendable cover members by thinning the glass, such as ultra-thin glass (UTG) (see, for example, Patent Documents 2 to 5). Among glass types, chemically strengthened glass has particularly high bending resistance. By incorporating expansion stress into the glass surface, minute scratches on the glass surface do not become larger when bent, making the glass less likely to break. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-137864 [Patent Document 2] Special Publication No. 2020-521699 [Patent Document 3] International Publication No. 2016 / 194785 [Patent Document 4] Special Publication No. 2016-508954 [Patent Document 5] International Publication No. 2020 / 095415 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the thinner the glass substrate, the lower the impact resistance, especially at the edges. In particular, in the case of chemically strengthened glass, when chemically strengthened glass is cut, the compressive stress layer formed on the surface of the chemically strengthened glass is not present on the cut surface of the glass substrate, resulting in a decrease in strength at the cut surface of the glass substrate.

[0007] The present disclosure has been made in view of the above circumstances, and a main object of the present disclosure is to provide a glass substrate and a glass laminate having good bending resistance and edge impact resistance. [Means for solving the problem]

[0008] One embodiment of the present disclosure provides a glass substrate having a first surface, a second surface opposite to the first surface, and a side surface connecting the first surface and the second surface, wherein the thickness of the glass substrate is 100 μm or less, the side surface is connected to the first surface, and has an inclined portion extending outward from an end of the first surface at an angle toward the second surface relative to the first surface, the width of the inclined portion in the first surface direction of the glass substrate is 0.05 μm or more and 9.00 μm or less, and the length of the inclined portion in the thickness direction of the glass substrate is 0.05 μm or more and 5.00 μm or less.

[0009] In the glass substrate of the present disclosure, it is preferable that the ratio (a / b) of the width a of the inclined portion in the first surface direction of the glass substrate to the length b of the inclined portion in the thickness direction of the glass substrate is 1.8 or more and 20.0 or less.

[0010] In the glass substrate according to the present disclosure, the inclined portion preferably has a curved surface that is convex outward.

[0011] In addition, in the glass substrate according to the present disclosure, the maximum height Sz of the side surface is preferably 1.5 μm or less.

[0012] Furthermore, in the glass substrate according to the present disclosure, when the regions formed by dividing the side surface into ten equal parts in the thickness direction are designated as first region to tenth region in the order from the first surface side to the second surface side, and when the maximum heights of the first region to tenth region of the side surface are designated as Sz1 to Sz10 in the order from the first region to the tenth region, respectively, it is preferable that the relationships of the following formulas (1) to (3) are satisfied. Sz1>Sz4 (1) Sz1>Sz5 (2) Sz1>Sz6 (3)

[0013] In the glass substrate according to the present disclosure, the side surface preferably has a flat portion connecting the inclined portion and the second surface.

[0014] The glass substrate in the present disclosure is preferably chemically strengthened glass.

[0015] Moreover, the glass substrate according to the present disclosure is preferably used in a foldable display device in which the first surface of the glass substrate faces outward.

[0016] Another embodiment of the present disclosure provides a glass laminate including the above-described glass substrate and a resin layer disposed on at least one of a first surface side and a second surface side of the glass substrate.

[0017] In the glass laminate according to the present disclosure, the resin layer is preferably disposed on the second surface side of the glass substrate.

[0018] Furthermore, the glass laminate according to the present disclosure preferably has a total light transmittance of 85% or more and a haze of 1.5% or less.

[0019] Another embodiment of the present disclosure provides a display device including a display panel and the above-described glass substrate or the above-described glass laminate disposed on a viewer side of the display panel.

[0020] The display device according to the present disclosure is preferably foldable so that the first surface of the glass substrate faces outward.

[0021] Another embodiment of the present disclosure provides an electronic device including the above-described display device. [Effects of the Invention]

[0022] The present disclosure has an effect of providing a glass substrate and a glass laminate having good bending resistance and edge impact resistance. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a glass substrate according to the present disclosure. [Figure 2]FIG. 1 is a schematic cross-sectional view illustrating a glass substrate according to the present disclosure. [Figure 3] FIG. 1 is a schematic cross-sectional view illustrating a glass substrate according to the present disclosure. [Figure 4] FIG. 1 is a schematic cross-sectional view illustrating a glass substrate according to the present disclosure. [Figure 5] FIG. 1 is a schematic plan view illustrating a glass substrate according to the present disclosure. [Figure 6] FIG. 1 is a schematic perspective view illustrating a glass substrate according to the present disclosure. [Figure 7] FIG. 1 is a schematic cross-sectional view illustrating a glass substrate according to the present disclosure. [Figure 8] FIG. 1 is a schematic diagram for explaining a U-shaped bending test. [Figure 9] 1 is a schematic cross-sectional view illustrating a glass laminate according to the present disclosure. [Figure 10] 1 is a schematic cross-sectional view illustrating a glass laminate according to the present disclosure. [Figure 11] 1 is a schematic cross-sectional view illustrating a glass laminate according to the present disclosure. [Figure 12] 1 is a schematic cross-sectional view illustrating a display device according to the present disclosure. [Figure 13] FIG. 1 is a schematic diagram for explaining an impact test. [Figure 14] FIG. 2 is an explanatory diagram illustrating a method for measuring the maximum height Sz. DETAILED DESCRIPTION OF THE INVENTION

[0024] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the preceding drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0025] In this specification, when describing a mode in which another component is placed on a certain component, the terms "above" or "below" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the terms "on the surface side" or "on the surface" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween.

[0026] The glass substrate, glass laminate, display device, and electronic device according to the present disclosure will be described in detail below.

[0027] A. Glass substrate The glass substrate according to the present disclosure has a first surface (hereinafter sometimes referred to as the first main surface), a second surface (hereinafter sometimes referred to as the second main surface) facing the first main surface, and a side surface connecting the first main surface and the second main surface, the glass substrate having a thickness of 100 μm or less, the side surface being connected to the first main surface and having an inclined portion extending outward from an end of the first main surface at an angle toward the second main surface with respect to the first main surface, the inclined portion having a width of 0.05 μm or more and 9.00 μm or less in the first main surface direction of the glass substrate, and a length of the inclined portion in the thickness direction of the glass substrate of 0.05 μm or more and 5.00 μm or less.

[0028] Here, in the present disclosure, "connected" refers to a state in which a predetermined member is disposed in contact with a predetermined surface (including an inclined portion). In the present disclosure, the "side surface" of the glass substrate refers to all surfaces of the glass substrate other than the first and second main surfaces. The "side surface" also includes the "inclined portion."

[0029] 1 and 2 are schematic cross-sectional views illustrating an example of a glass substrate according to the present disclosure, and FIG. 2 is an enlarged view of FIG. 1. As shown in FIGS. 1 and 2, glass substrate 1 has a first main surface 1A, a second main surface 1B opposing first main surface 1A, and a side surface 1C connecting first main surface 1A and second main surface 1B. The side surface 1C of glass substrate 1 has an inclined portion 2a connected to first main surface 1A and extending outward from an end of first main surface 1A toward second main surface 1B with respect to first main surface 1A. The width a of inclined portion 2a in the direction of the first main surface of glass substrate 1 is within a predetermined range, and the length b of inclined portion 2a in the thickness direction of glass substrate 1 is within a predetermined range. Furthermore, in FIGS. 1 and 2, side surface 1C of glass substrate 1 has a flat portion 2b connecting inclined portion 2a and second main surface 1B.

[0030] The "end of the first surface" refers to the boundary between the first surface and the inclined portion of the side surface. For example, in Fig. 2, the end of the first surface 1A is the boundary between the first surface 1A and the inclined portion 2a of the side surface 1C.

[0031] Additionally, the "outside" in "from the end of the first surface to the outside" refers to the side opposite the glass substrate from the flat surface of the side surface. Furthermore, the "first surface direction of the glass substrate" in "the inclined portion in the first surface direction of the glass substrate" refers to a direction perpendicular to the thickness direction of the glass substrate.

[0032] The glass substrate of the present disclosure has a thin thickness of a predetermined value or less, which allows for high flexibility and improved bending resistance. However, the glass substrate is prone to microcracks during processing, particularly at the edges of the glass substrate when the glass substrate is cut. Microcracks in the glass substrate make it more likely for cracks to originate from these microcracks. Furthermore, using chemically strengthened glass as the glass substrate can improve bending resistance and impact resistance. However, even in this case, when cutting a glass substrate made of chemically strengthened glass, the compressive stress layer formed on the surface of the chemically strengthened glass is not present on the cut surface, i.e., the side surface, of the glass substrate, resulting in reduced strength on the side surface of the glass substrate.

[0033] In contrast, in the present disclosure, the side surface 1C of the glass substrate 1 has an inclined portion 2a. The width a of the inclined portion 2a in the direction of the first principal surface of the glass substrate 1 and the length b of the inclined portion 2a in the thickness direction of the glass substrate 1 are within a predetermined range, thereby improving the impact resistance of the edge of the glass substrate. While the reason for this is unclear, it is presumed as follows. That is, the inclined portion 2a on the side surface 1C can prevent stress from concentrating on the corner of the glass substrate when the edge of the glass substrate is subjected to an impact. Furthermore, the length b of the inclined portion 2a in the direction of the thickness of the glass substrate 1 is within a predetermined range and is relatively small, thereby enabling the area of ​​the flat portion 2b on the side surface 1C of the glass substrate 1 to be relatively large. Furthermore, the width a of the inclined portion 2a in the direction of the first principal surface of the glass substrate 1 is within a predetermined range and is relatively small, thereby enabling the area of ​​the edge of the glass substrate 1 where the thickness is thinner than the thickness T, which is the length between the first principal surface 1A and the second principal surface 1B, to be relatively small. This increases the strength of the edge of the glass substrate, thereby improving the impact resistance of the edge of the glass substrate.

[0034] Therefore, in the present disclosure, it is possible to obtain a glass substrate having good bending resistance and edge impact resistance. Therefore, the glass substrate in the present disclosure can be bent and used in a wide variety of display devices, for example, as a component for a foldable display.

[0035] The thickness of the glass substrate is 100 μm or less, preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 90 μm or less, and even more preferably 25 μm or more and 80 μm or less. A glass substrate having a thin thickness within the above range can provide good flexibility and sufficient hardness. It can also suppress curling of the glass substrate. Furthermore, this is preferable in terms of reducing the weight of the glass substrate. The thickness of the glass substrate refers to the length between the first and second main surfaces of the glass substrate.

[0036] In the glass substrate, the inclined portion 2a may have, for example, a flat surface as shown in Fig. 2, or may have a curved surface that is convex outward as shown in Fig. 3. In particular, it is preferable that the inclined portion have a curved surface that is convex outward, because this can effectively prevent stress from concentrating on the corners of the glass substrate when the edge of the glass substrate is subjected to an impact.

[0037] It should be noted that the "outside" in the "curved surface that is convex outward" refers to the side opposite the glass substrate itself with respect to a plane that connects the boundary between the inclined portion and the first surface and the boundary between the inclined portion and the side surface that is perpendicular to the first surface.

[0038] In the glass substrate, the width a of the inclined portion in the first principal surface direction of the glass substrate can be 0.05 μm or more, preferably 0.5 μm or more. If the width a of the inclined portion in the first principal surface direction of the glass substrate is too small, stress is likely to concentrate at the corners of the glass substrate when the end of the glass substrate receives an impact, which may result in cracking. On the other hand, the width a of the inclined portion in the first principal surface direction of the glass substrate can be 9.00 μm or less, preferably 5.0 μm or less. When the width a of the inclined portion in the first principal surface direction of the glass substrate is relatively small within the above range, the thin portion of the glass substrate at the end of the glass substrate can be made relatively small, and the strength of the end of the glass substrate can be increased.

[0039] Furthermore, in the glass substrate, the length b of the inclined portion in the thickness direction of the glass substrate can be 0.05 μm or more, preferably 0.1 μm or more. If the length b of the inclined portion in the thickness direction of the glass substrate is too small, stress is likely to concentrate at the corners of the glass substrate when the end of the glass substrate receives an impact, which may result in cracking. On the other hand, the length b of the inclined portion in the thickness direction of the glass substrate can be 5.00 μm or less, preferably 2.0 μm or less. When the length b of the inclined portion in the thickness direction of the glass substrate is relatively small within the above range, the area of ​​the flat portion on the side surface can be relatively large, and the strength of the end of the glass substrate can be increased.

[0040] In the present disclosure, the width a and length b can be adjusted to the above-mentioned ranges by, for example, a polishing process in the processing step shown in the manufacturing method described below. Adjustments can also be made by changing the cutter pressure during cutting and the tempering conditions for chemically tempered glass.

[0041] Specifically, increasing the cutter pressure during cutting tends to increase a and decrease b. Furthermore, by setting the tempering conditions of chemically strengthened glass to those that increase the surface stress value and increase the thickness of the strengthened layer, a and b tend to decrease. In the present disclosure, these settings make it possible to adjust a and b.

[0042] Furthermore, as will be described later, when the glass substrate is chemically strengthened glass, the ratio (a / b) of the width a of the inclined portion in the first principal surface direction of the glass substrate to the length b of the inclined portion in the thickness direction of the glass substrate is, for example, preferably 1.8 or more, more preferably 2.3 or more. By having a / b in the above range, the inclination of the inclined portion can be made relatively gentle.

[0043] Here, in the manufacturing process of a glass substrate, for example, if chemical strengthening treatment and cutting are performed in that order, no compressive stress layer will be present on the side surface of the glass substrate. In this case, if a / b is smaller than the above range and the inclination of the inclined portion is relatively steep, the area where the compressive stress layer 3 is not present tends to be relatively large on the flat portion 2b of the side surface 1C of the glass substrate 1, as shown in FIG. 4(a), for example. In contrast, if a / b is within the above range and the inclination of the inclined portion is relatively gentle, it is easier to ensure an area where the compressive stress layer 3 is present on the flat portion 2b of the side surface 1C of the glass substrate 1, as shown in FIG. 4(b), for example. Therefore, in the above case, it is presumed that having a / b within the above range can improve the impact resistance of the edge of the glass substrate.

[0044] Furthermore, in the manufacturing process of a glass substrate, for example, when cutting and chemical strengthening are performed in that order, a compressive stress layer will also be present on the side surface of the glass substrate. In this case, if a / b is smaller than the above range and the inclination of the inclined portion is relatively steep, the compressive stress tends to be generated non-uniformly in the compressive stress layer formed on the side surface of the glass substrate. Non-uniform compressive stress is likely to cause residual distortion, which is thought to affect fracture. In contrast, if a / b is within the above range and the inclination of the inclined portion is relatively gentle, the compressive stress tends to be uniform in the compressive stress layer formed on the side surface of the glass substrate. Therefore, even in the above case, it is presumed that the impact resistance of the edge of the glass substrate can be improved by having a / b within the above range.

[0045] Furthermore, when the glass substrate is chemically strengthened glass, the ratio (a / b) of the width a of the inclined portion in the first main surface direction of the glass substrate to the length b of the inclined portion in the thickness direction of the glass substrate is, for example, preferably 20.0 or less, and more preferably 10.0 or less. If a / b is too large, the slope of the inclined portion becomes too gentle, and when the edge of the glass substrate receives an impact, stress is likely to concentrate at the corners of the glass substrate, which may cause cracks. In the present disclosure, the above a / b is preferably within the range of 1.8 to 20.0, and particularly preferably within the range of 2.3 to 10.0.

[0046] Here, the width a of the inclined portion in the direction of the first principal surface of the glass substrate refers to the width of the inclined portion 2a when the glass substrate 1 is viewed in a plan view in the thickness direction, as shown in Figures 5(a) and 5(b), for example. When the inclined portion has a curved surface that is convex outward, as shown in Figure 3, for example, the boundary between the first principal surface 1A and the inclined portion 2a is the boundary between the flat surface that constitutes the first principal surface 1A and the curved surface that constitutes the inclined portion 2a; that is, the R of the curved surface that constitutes the inclined portion 2a ends at the first principal surface 1A side. Note that Figure 1 corresponds to the cross-sectional view taken along line AA in Figure 5(a) and the cross-sectional views taken along lines AA and BB in Figure 5(b).

[0047] Furthermore, the length b of the inclined portion in the thickness direction of the glass substrate refers to the height of the inclined portion 2a, as shown in Figures 2 and 3. When the inclined portion has a curved surface that convex outward, as shown in Figure 3, for example, the boundary between the inclined portion 2a and the flat portion 2b is the boundary between the curved surface that constitutes the inclined portion 2a and the flat surface that constitutes the flat portion 2b, i.e., the R of the curved surface that constitutes the inclined portion 2a ends at the end of the flat portion 2b side.

[0048] In the glass substrate, it is sufficient that at least a part of the side surface has the inclined portion, for example, all of the side surfaces may have the inclined portion, or only a part of the side surfaces may have the inclined portion. Furthermore, when the glass substrate has a rectangular parallelepiped shape, it is sufficient that at least one of the four side surfaces has the inclined portion, for example, two opposing side surfaces may have the inclined portion, or all of the four side surfaces may have the inclined portion.

[0049] When the glass substrate has a rectangular parallelepiped shape, it is particularly preferable that two of the four side surfaces facing each other have the inclined portions. For example, as shown in Figures 6(a) and 6(b), when the glass substrate 1 is bent, the bent portion F1 of the glass substrate 1 is likely to crack if it receives an impact. Therefore, by having the inclined portions on two of the four side surfaces of the glass substrate that are approximately parallel to the bending direction D1 of the glass substrate 1, the strength of the bent portion of the glass substrate can be increased, and the impact resistance of the bent portion can be improved.

[0050] Furthermore, when the glass substrate has a rectangular shape when viewed in plan from the thickness direction, it is preferable that, of the four side surfaces of the glass substrate, two side surfaces that are approximately parallel to the long side direction of the glass substrate have the inclined portions 2a, as shown in Fig. 5(a), for example. For example, as shown in Figs. 6(a) and 6(b), when bending a glass substrate 1, the bending direction D1 of the glass substrate 1 is often made approximately parallel to the long side direction of the glass substrate because it is easy to bend. Therefore, by having the inclined portions on two side surfaces that are approximately parallel to the long side direction of the glass substrate, of the four side surfaces of the glass substrate, the strength of the bent portion of the glass substrate can be increased, and the impact resistance of the bent portion can be improved.

[0051] Furthermore, for the reasons mentioned above, it is preferable that, of the four side surfaces of the glass substrate, two side surfaces that are approximately parallel to the bending direction of the glass substrate have the inclined portions.

[0052] In particular, it is preferable that all four side surfaces of the glass substrate have the inclined portions, as shown in Fig. 5(b), for example, as this can improve the impact resistance of the edge of the glass substrate.

[0053] Furthermore, the side surface of the glass substrate needs to have at least an inclined portion, but preferably has an inclined portion and a flat portion connecting the inclined portion and the second main surface.

[0054] Here, since the side surface of the glass substrate has an inclined portion connected to the first main surface, when the glass substrate is folded so that the first main surface faces outward, the glass substrate is folded so that the inclined portion faces outward. If the glass substrate is chemically strengthened glass, the compressive stress layer is thinner at the inclined portion, so the compressive stress value is lower on the first surface side of the glass substrate than on the second surface side. The lower the compressive stress value, the easier it is to bend. Therefore, when the glass substrate is folded so that the inclined portion faces outward, it is easier to bend and has better bending resistance than when the glass substrate is folded so that the inclined portion faces inward. Therefore, when the side surface of the glass substrate has an inclined portion and a flat portion connecting the inclined portion and the second main surface, when the glass substrate is folded so that the first main surface faces outward, it has better bending resistance than when the glass substrate is folded so that the second main surface faces outward.

[0055] On the other hand, when the side surface of the glass substrate has, for example, a first inclined portion connected to the first main surface, a second inclined portion connected to the second main surface, and a flat portion connected to the first inclined portion and the second inclined portion, when the glass substrate is folded so that the first main surface faces outward, the first inclined portion faces outward and the second inclined portion faces inward, and when the glass substrate is folded so that the second main surface faces outward, the first inclined portion faces inward and the second inclined portion faces outward. Therefore, when the side surface of the glass substrate has, for example, a first inclined portion connected to the first main surface, a second inclined portion connected to the second main surface, and a flat portion connected to the first inclined portion and the second inclined portion, the bending resistance when the glass substrate is folded so that the first main surface faces outward and the bending resistance when the glass substrate is folded so that the second main surface faces outward are expected to be similar to the bending resistance when the side surface of the glass substrate has an inclined portion and a flat portion connecting the inclined portion and the second main surface and is folded so that the inclined portion faces inward.

[0056] Therefore, when the side surface of the glass substrate has an inclined portion and a flat portion connecting the inclined portion and the second main surface, it is presumed that the bending resistance can be improved when the glass substrate is folded so that the inclined portion faces outward, i.e., when the glass substrate is folded so that the first main surface of the glass substrate faces outward, compared to when the side surface of the glass substrate has, for example, a first inclined portion connected to the first main surface, a second inclined portion connected to the second main surface, and a flat portion connecting the first inclined portion and the second inclined portion. Therefore, it is preferable that the side surface of the glass substrate has an inclined portion and a flat portion connecting the inclined portion and the second main surface.

[0057] Furthermore, the maximum height Sz of the side surface of the glass substrate is preferably, for example, 1.5 μm or less, and more preferably 1.0 μm or less. When the maximum height Sz of the side surface of the glass substrate is within the above range, the smoothness of the side surface of the glass substrate is high, thereby reducing microcracks on the side surface of the glass substrate, and as a result, increasing the strength of the side surface of the glass substrate. This makes it possible to suppress cracking from the side surface of the glass substrate when the glass substrate is bent, thereby improving bending resistance. Furthermore, it is possible to improve the impact resistance of the edge of the glass substrate during the manufacture and use of the glass substrate, display device components, and display devices using the glass substrate. On the other hand, the maximum height Sz of the side surface of the glass substrate is preferably 0.005 μm or more. If Sz is less than 0.005 μm, poor adhesion may occur, making it difficult to cover the edge. In the present disclosure, the above Sz is preferably in the range of 0.005 μm to 1.5 μm, and particularly preferably in the range of 0.005 μm to 1.0 μm.

[0058] Here, the maximum height Sz is a value measured in accordance with ISO 25178. The maximum height Sz can be measured using a non-contact surface profile measuring device that uses optical interference. As a non-contact surface profile measuring device that uses optical interference, for example, the VertScan2.0 R5500GML-A150-AC non-contact surface / layer cross-sectional shape measuring system manufactured by Ryoka Systems Co., Ltd. can be used. Details of the method for measuring the maximum height Sz will be described in the Examples section below. In the present disclosure, Sz is a parameter for evaluating surface roughness, and is more effective for evaluating irregular surface properties than Rz, which indicates line roughness.

[0059] Furthermore, when the side surface of the glass substrate is divided into ten equal regions in the thickness direction and the regions are designated as the first region to the tenth region in the order from the first main surface side to the second main surface side, and when the maximum heights of the first region to the tenth region on the side surface are designated as Sz1 to Sz10 in the order from the first region to the tenth region, respectively, it is preferable that the relationships of the following formulas (1) to (3) are satisfied. Sz1>Sz4 (1) Sz1>Sz5 (2) Sz1>Sz6 (3) When the relationships of the above formulas (1) to (3) are satisfied, the smoothness of the central portion in the thickness direction of the side surface of the glass substrate is relatively high, which makes it possible to suppress the progression of microcracks on the side surface of the glass substrate.

[0060] 7, the regions formed by dividing the side surface 1C of the glass substrate 1 equally in the thickness direction of the glass substrate 1 are designated as a first region 4A to a tenth region 4J in order from the first main surface 1A side to the second main surface 1B side of the glass substrate 1. The maximum heights Sz of the first region 4A to the tenth region 4J of the side surface 1C of the glass substrate 1 are designated as Sz1 to Sz10 in order from the first region 4A to the tenth region 4J. That is, for example, the maximum height Sz of the first region 4A is designated as Sz1, the maximum height Sz of the second region 4B is designated as Sz2, and the maximum height Sz of the third region 4C is designated as Sz3.

[0061] In the glass substrate, it is sufficient that the maximum height Sz of at least a part of the side surfaces is within a predetermined range, for example, the maximum height Sz of all the side surfaces may be within a predetermined range, or the maximum height Sz of only a part of the side surfaces may be within a predetermined range. Furthermore, when the glass substrate is rectangular, it is sufficient that the maximum height Sz of at least one of the four side surfaces is within a predetermined range.

[0062] When the glass substrate has a rectangular parallelepiped shape, it is particularly preferable that the maximum heights Sz of two opposing side surfaces of the four side surfaces are within a predetermined range. For example, as shown in Figures 6(a) and 6(b), when the glass substrate 1 is bent, cracks are likely to occur in the glass substrate 1 at the bent portion F1 of the glass substrate 1. Therefore, if the maximum heights Sz of the two side surfaces that are approximately parallel to the bending direction D1 of the glass substrate 1 of the four side surfaces of the glass substrate are within the above range, cracks can be suppressed from occurring at the bent portion when the glass substrate is bent, and bending resistance can be improved.

[0063] Furthermore, when the glass substrate has a rectangular shape when viewed in plan from the thickness direction, it is preferable that the maximum height Sz of two of the four side surfaces of the glass substrate that are approximately parallel to the long side direction of the glass substrate be within the above range. For example, as shown in Figures 6(a) and 6(b), when bending a glass substrate 1, the bending direction D1 of the glass substrate 1 is often made approximately parallel to the long side direction of the glass substrate because it is easy to bend. Therefore, if the maximum height Sz of two of the four side surfaces of the glass substrate that are approximately parallel to the long side direction of the glass substrate are within the above range, cracks can be suppressed from occurring in the bent portion of the glass substrate when the glass substrate is bent, and bending resistance can be improved.

[0064] Furthermore, for the reasons mentioned above, it is preferable that the maximum height Sz of two of the four side surfaces of the glass substrate that are approximately parallel to the bending direction of the glass substrate be within the above range.

[0065] In particular, it is preferable that the maximum heights Sz of all four side surfaces of the glass substrate are within a predetermined range. This can further suppress cracking of the glass substrate when the glass substrate is bent, thereby further improving bending resistance. Furthermore, it can improve the impact resistance of the edge of the glass substrate.

[0066] The glass constituting the glass substrate is not particularly limited, but chemically strengthened glass is preferable. Chemically strengthened glass has better impact resistance and bending resistance than non-strengthened glass. In addition, chemically strengthened glass is preferable in that it has excellent mechanical strength and can be made thinner accordingly.

[0067] Chemically strengthened glass is typically glass whose mechanical properties are strengthened by a chemical method by partially exchanging sodium ions for potassium ions near the surface of the glass, and has a compressive stress layer on the surface. That is, chemically strengthened glass is glass in which a large amount of potassium is present on the surface and compressive stress is applied to the surface.

[0068] Examples of glasses that can be used to form chemically strengthened glass substrates include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

[0069] Examples of commercially available chemically strengthened glass substrates include Gorilla Glass from Corning, Dragontrail from AGC, and chemically strengthened glass from Schott.

[0070] The glass substrate in the present disclosure preferably has flex resistance. Specifically, the flex resistance of the glass substrate can be evaluated by carrying out the U-shaped flex test described below.

[0071] The U-shaped bending test is performed as follows. First, a glass substrate test piece measuring 20 mm × 100 mm is prepared. Next, as shown in FIG. 8(a), a short side 1P of the glass substrate 1 and a short side 1Q opposite the short side 1P are fixed by parallel-arranged fixing parts 100A and 100B, respectively. As shown in FIG. 8(a), fixing part 100B is slidable horizontally. Next, as shown in FIG. 8(b), fixing part 100B is moved closer to fixing part 100A, thereby bending the glass substrate 1 into a U-shape. Furthermore, as shown in FIG. 8(c), fixing part 100B is moved to gradually reduce the distance d between the two opposing short sides 1P and 1Q of the glass substrate 1 fixed by fixing parts 100A and 100B until cracks or fractures occur in the glass substrate 1. At this time, the bending test is performed so that the bending portion 1R of the glass substrate 1 does not protrude from the lower ends of the fixing portions 100A and 100B. For example, if the distance d between the two opposing short side portions 1P and 1Q is 10 mm, the outer diameter of the bending portion 1R is considered to be 10 mm.

[0072] In the U-bend test, the distance d between the opposing short sides 1P and 1Q of the glass substrate 1 when cracks or breakage occurs is preferably 10 mm or less, more preferably 8 mm or less, and particularly preferably 5 mm or less. The smaller the distance d between the opposing short sides 1P and 1Q of the glass substrate 1, the higher the bending resistance.

[0073] As described above, when the glass substrate is folded so that the first main surface faces outward, the bending resistance is higher than when the glass substrate is folded so that the second main surface faces outward. Therefore, in the U-shaped bending test, it is preferable that the glass substrate has the above-mentioned bending resistance when folded so that the first main surface of the glass substrate faces outward. In particular, it is more preferable that the glass substrate has the above-mentioned bending resistance when folded so that the first main surface of the glass substrate faces outward and when folded so that the first main surface of the glass substrate faces inward.

[0074] The bending resistance of a glass substrate can also be evaluated by a dynamic bending test, which is a test in which the distance d between the opposing short sides 1P and 1Q of the glass substrate 1 is set to a predetermined value in the U-shaped bending test described above, and the glass substrate is repeatedly bent.

[0075] In the dynamic bending test, it is preferable that the glass substrate does not crack or break when the operation of bending the glass substrate 1 by 180° so that the distance d between the opposing short sides 1P and 1Q of the glass substrate 1 is 12 mm is repeated 200,000 times.

[0076] Furthermore, in the dynamic bending test, when the number of samples is 10, it is preferable that the pass rate calculated by the following formula from the total number of samples (10) and the number of samples in which cracks or breaks did not occur in the glass substrate is 80% or more. Pass rate (%) = (number of samples with no cracks or breaks in the glass substrate) / 10 x 100

[0077] Furthermore, by reducing the thickness of the glass substrate, the bending resistance can be improved.

[0078] For example, when the thickness of the glass substrate is 81 μm or more and 100 μm or less, it is preferable that the glass substrate does not crack or break when the above-mentioned dynamic bending test involves repeatedly bending the glass substrate 1 by 180° 200,000 times so that the distance d between the opposing short side portions 1P and 1Q of the glass substrate 1 is 12 mm.

[0079] Furthermore, for example, when the thickness of the glass substrate is 50 μm or more and 81 μm or less, it is preferable that the glass substrate does not crack or break when the above-mentioned dynamic bending test involves repeatedly bending the glass substrate 1 by 180° 200,000 times so that the distance d between the opposing short side portions 1P and 1Q of the glass substrate 1 is 10 mm.

[0080] Furthermore, for example, when the thickness of the glass substrate is 50 μm or less, it is preferable that the glass substrate does not crack or break when the above-mentioned dynamic bending test involves repeatedly bending the glass substrate 1 by 180° 200,000 times so that the distance d between the opposing short side portions 1P and 1Q of the glass substrate 1 is 8 mm.

[0081] In the dynamic bending test, similarly to the above-mentioned U-shaped bending test, it is preferable that the above-mentioned bending resistance be exhibited when the glass substrate is folded so that the first main surface of the glass substrate faces outward, and it is more preferable that the above-mentioned bending resistance be exhibited when the glass substrate is folded so that the first main surface of the glass substrate faces outward and when the glass substrate is folded so that the first main surface of the glass substrate faces inward.

[0082] The method for manufacturing a glass substrate according to the present disclosure is not particularly limited as long as it can form an inclined portion on a side surface of the glass substrate, and can set the width a of the inclined portion in the first principal surface direction of the glass substrate within a predetermined range and the length b of the inclined portion in the thickness direction of the glass substrate within a predetermined range. For example, the method for manufacturing a glass substrate may include a cutting step of cutting the glass substrate so that an inclined portion is formed on the side surface of the glass substrate, the width a of the inclined portion in the first principal surface direction of the glass substrate falls within a predetermined range, and the length b of the inclined portion in the thickness direction of the glass substrate falls within a predetermined range. Furthermore, for example, the method for manufacturing a glass substrate may include a cutting step of cutting the glass substrate and a processing step of processing the cut surface of the glass substrate so that an inclined portion is formed on the side surface of the glass substrate, the width a of the inclined portion in the first principal surface direction of the glass substrate falls within a predetermined range, and the length b of the inclined portion in the thickness direction of the glass substrate falls within a predetermined range. Among these, it is preferable that the method for manufacturing a glass substrate includes cutting the glass substrate so that an inclined portion is formed on the side surface of the glass substrate, the width a of the inclined portion in the first principal surface direction of the glass substrate falls within a predetermined range, and the length b of the inclined portion in the thickness direction of the glass substrate falls within a predetermined range.

[0083] Examples of methods for cutting the glass substrate include scribing methods such as mechanical scribing using a tool or laser scribing, chemical etching, laser cutting, etc. Specifically, a mechanical scribing method using a cutter "SOLID-D" manufactured by Mitsuboshi Diamond Industrial Co., Ltd. is preferably used.

[0084] In addition, when the glass substrate is chemically strengthened glass, for example, the chemical strengthening treatment and cutting process may be performed in that order, or the cutting process and chemical strengthening treatment may be performed in that order. When the chemical strengthening treatment and cutting process are performed in that order, for example, when a display device component is manufactured using a glass substrate, the subsequent manufacturing process can be carried out without cutting a large glass substrate, thereby improving production efficiency.

[0085] The glass substrate according to the present disclosure can be used, for example, as a cover member for a display device. Specifically, the glass substrate according to the present disclosure can be used as a cover member for a display device used in electronic devices such as smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays. In particular, the glass substrate according to the present disclosure can be preferably used for flexible displays such as foldable displays, rollable displays, and bendable displays, and is more preferably used for foldable displays.

[0086] In particular, the glass substrate according to the present disclosure is preferably used in a foldable display device with the first main surface of the glass substrate facing outward. As described above, when the glass substrate is folded so that the first main surface faces outward, the bending resistance is higher than when the glass substrate is folded so that the second main surface faces outward. Therefore, the glass substrate according to the present disclosure is preferably used in a foldable display device with the first main surface of the glass substrate facing outward.

[0087] B. Glass Laminate The glass laminate of the present disclosure includes the above-described glass substrate and a resin layer disposed on at least one of the first and second main surfaces of the glass substrate.

[0088] 9 to 11 are schematic cross-sectional views showing an example of a glass laminate according to the present disclosure. As illustrated in FIG. 9, a glass laminate 10 may include a glass substrate 1 and a resin layer 11 disposed on a first main surface 1A side of the glass substrate 1. As illustrated in FIG. 10, the glass laminate 10 may include a glass substrate 1 and a resin layer 12 disposed on a second main surface 1B side of the glass substrate 1. As illustrated in FIG. 11, the glass laminate 10 may include a glass substrate 1, a resin layer 11 disposed on a first main surface 1A side of the glass substrate 1, and a resin layer 12 disposed on a second main surface 1B side of the glass substrate 1.

[0089] The glass laminate according to the present disclosure has the above-described glass substrate, which allows for improved bending resistance and edge impact resistance. Therefore, the glass laminate according to the present disclosure is bendable and can be used in a wide variety of display devices, for example, as a component for a foldable display.

[0090] Hereinafter, each component of the glass laminate according to the present disclosure will be described.

[0091] 1. Glass substrate The glass substrate used in the glass laminate of the present disclosure is the same as that described in the above section "A. Glass substrate," and therefore, description thereof will be omitted here.

[0092] 2. Resin layer The resin layer in the present disclosure is a layer disposed on at least one of the first and second main surfaces of the glass substrate.

[0093] Examples of the resin layer include an impact absorbing layer, a shatterproof layer, a hard coat layer, a protective layer, an anti-reflection layer, a low-reflection layer, an anti-glare layer, an anti-static layer, and a decorative layer.

[0094] The resin layer may be a single layer or may have multiple layers, and may be a layer having a single function or may have multiple layers having different functions.

[0095] In the glass laminate of the present disclosure, the resin layer may be disposed on at least one of the first and second main surfaces of the glass substrate. For example, the resin layer may be disposed only on the first main surface of the glass substrate, only on the second main surface of the glass substrate, or on both the first and second main surfaces of the glass substrate. Among these, the resin layer is preferably disposed on the second main surface of the glass substrate. When the resin layer is disposed on the second main surface of the glass substrate, in the manufacture of the glass laminate, for example, the resin layer can be formed on the glass substrate, and then the laminate of the glass substrate and the resin layer can be cut. In this case, for example, when a display device component is manufactured using the glass laminate, subsequent manufacturing steps can be carried out without cutting large glass substrates, thereby improving production efficiency.

[0096] The material of the resin layer is appropriately selected depending on the intended function, etc. The resin contained in the resin layer may be any resin as long as it has transparency, and a general resin may be used. For example, polyimide, polyimide amide, polyethylene terephthalate (PET), cycloolefin polymer (COP), triacetyl cellulose (TAC), acrylic resin, polycarbonate (PC), and epoxy resin are preferably used.

[0097] The resin layer may contain additives as needed, such as ultraviolet absorbers, light stabilizers, antioxidants, fillers, antistatic agents, antifouling agents, surfactants, lubricants, flame retardants, plasticizers, and colorants.

[0098] The thickness of the resin layer is not particularly limited as long as it provides flexibility, and is appropriately selected depending on the intended function, etc. The thickness of the resin layer is, for example, 2 μm or more, and may be 5 μm or more, 10 μm or more, or 15 μm or more. The thickness of the resin layer is, for example, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. When the resin layer has a relatively thin thickness within the above range, flexibility can be increased, cracking of the resin layer can be suppressed when the glass laminate is bent, and bending resistance can be maintained.

[0099] Here, the thickness of the resin layer can be the average value of thicknesses measured at any 10 locations on a cross section of the glass laminate in the thickness direction observed with a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM). Unless otherwise specified, the same method can be used to measure the thickness of other layers in the glass laminate.

[0100] Examples of methods for forming a resin layer include a method of applying a resin composition onto a glass substrate. The application method is not particularly limited as long as it can be applied to a desired thickness, and examples include common application methods such as gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. In addition, methods for forming a resin layer can also include a transfer method in which a resin layer is transferred to one side of a glass substrate, or a method in which a film-like resin layer is attached to one side of a glass substrate via an adhesive layer.

[0101] The adhesive layer has transparency. Specifically, the total light transmittance of the adhesive layer is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. The upper limit of the total light transmittance is 100%.

[0102] Examples of adhesives used in the adhesive layer include pressure sensitive adhesives such as OCA (Optical Clear Adhesive), heat sealing agents, and photosensitive adhesives.

[0103] The thickness of the adhesive layer is preferably, for example, 1 μm or more and 100 μm or less. If the adhesive layer is too thick, the flex resistance may be impaired. On the other hand, if the adhesive layer is too thin, the adhesiveness may not be ensured and the adhesive layer may peel off.

[0104] 3. Other configurations In addition to the above-described layers, the glass laminate of the present disclosure may also include other layers as needed. Examples of other layers include a primer layer.

[0105] The glass laminate according to the present disclosure may have a primer layer between the glass substrate and the resin layer. The primer layer can improve adhesion between the glass substrate and the resin layer.

[0106] The material for the primer layer is not particularly limited as long as it can improve the adhesion between the glass substrate and the resin layer, and examples thereof include resins. Examples of resins include (meth)acrylic resins, urethane resins, (meth)acrylic urethane copolymers, vinyl chloride-vinyl acetate copolymers, polyesters, butyral resins, chlorinated polypropylene, chlorinated polyethylene, epoxy resins, and silicone resins. These resins may be used alone or in combination of two or more.

[0107] The thickness of the primer layer may be any thickness that can enhance the adhesion between the glass substrate and the resin layer, and may be, for example, 0.1 μm or more and 10 μm or less, and preferably 0.2 μm or more and 5 μm or less.

[0108] The method for forming the primer layer may be, for example, a method of applying a primer layer composition onto a glass substrate. Examples of the application method include general application methods such as gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, and screen printing. Alternatively, a transfer method may be used to form the primer layer.

[0109] 4. Characteristics of glass laminates The glass laminate according to the present disclosure preferably has a total light transmittance of, for example, 85% or more, and more preferably 88% or more. Such a high total light transmittance allows the glass laminate to have good transparency. The upper limit of the total light transmittance is 100%.

[0110] Here, the total light transmittance of the glass laminate can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0111] The haze of the glass laminate of the present disclosure is, for example, preferably 1.5% or less, and more preferably 1.0% or less. Such a low haze allows the glass laminate to have good transparency. The lower limit of the haze is 0%.

[0112] The haze of the glass laminate can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0113] The glass laminate according to the present disclosure preferably has flex resistance. Specifically, when the glass laminate is subjected to the U-bend test described above, the distance between opposing short sides of the glass laminate at the time when cracks or breakage occurs in the glass laminate is preferably 10 mm or less, more preferably 5 mm or less.

[0114] As described above, when the glass substrate is folded so that the first main surface faces outward, the bending resistance is higher than when the glass substrate is folded so that the second main surface faces outward. Therefore, in a U-shaped bending test, it is preferable that the glass laminate have the above-mentioned bending resistance when folded so that the first main surfaces of the glass substrates face outward. In particular, it is more preferable that the glass laminate have the above-mentioned bending resistance when folded so that the first main surfaces of the glass substrates face outward and when folded so that the first main surfaces of the glass substrates face inward.

[0115] Furthermore, when the above-mentioned dynamic bending test is performed on the glass laminate, it is preferable that the glass laminate does not crack or break when the glass laminate is repeatedly bent 200,000 times so that the distance between opposing short sides of the glass laminate is 12 mm.

[0116] Furthermore, in the dynamic bending test, when the number of samples is 10, it is preferable that the pass rate calculated by the following formula from the total number of samples (10) and the number of samples in which cracks or breaks did not occur in the glass laminate is 80% or more. Pass rate (%) = (number of samples with no cracks or breaks in the glass laminate) / 10 x 100

[0117] In the dynamic bending test, similarly to the above-mentioned U-bending test, it is preferable that the above-mentioned bending resistance be exhibited when the glass laminate is folded so that the first main surfaces of the glass substrates face outward, and it is more preferable that the above-mentioned bending resistance be exhibited both when the glass laminate is folded so that the first main surfaces of the glass substrates face outward and when the glass laminate is folded so that the first main surfaces of the glass substrates face inward.

[0118] 5. Applications of glass laminates The glass laminate according to the present disclosure can be used as a component arranged on the viewer's side of the display panel in a display device. The glass laminate according to the present disclosure can be used in display devices used in electronic devices such as smartphones, tablet devices, wearable devices, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays. In particular, the glass laminate according to the present disclosure can be preferably used in flexible displays such as foldable displays, rollable displays, and bendable displays, and is more preferably used in foldable displays.

[0119] In particular, the glass laminate according to the present disclosure is preferably used in a foldable display device in which the first main surface of the glass substrate faces outward. As described above, when the glass substrate is folded so that the first main surface faces outward, bending resistance can be improved compared to when the glass substrate is folded so that the second main surface faces outward.

[0120] When the glass laminate according to the present disclosure is disposed on the surface of a display device, it may be disposed so that the first main surface of the glass substrate faces the display panel, or so that the second main surface of the glass substrate faces the display panel. Furthermore, for example, when a foldable display device is folded so that the screen faces inward, it is preferable to fold it so that the first main surface of the glass substrate faces outward, as described above. Therefore, it is preferable that the glass laminate be disposed so that the first main surface of the glass substrate faces the display panel. On the other hand, for example, when a foldable display device is folded so that the screen faces outward, it is preferable that the glass laminate be disposed so that the second main surface of the glass substrate faces the display panel, as described above.

[0121] The method for disposing the glass laminate of the present disclosure on the surface of the display device is not particularly limited, and examples thereof include a method using an adhesive layer, etc. As the adhesive layer, a known adhesive layer used for bonding glass laminates can be used.

[0122] C.Display device A display device according to the present disclosure includes a display panel and the above-described glass substrate or the above-described glass laminate disposed on the viewer side of the display panel.

[0123] Fig. 12 is a schematic cross-sectional view showing an example of a display device according to the present disclosure, which is an example including the above-described glass laminate. As shown in Fig. 12, display device 20 includes display panel 21 and glass laminate 10 arranged on the viewer side of display panel 21. In display device 20, glass laminate 10 is used as a member arranged on the surface of display device 20, and adhesive layer 22 is arranged between glass laminate 10 and display panel 21.

[0124] The glass substrate and glass laminate in the present disclosure may be similar to the glass substrate and glass laminate described above.

[0125] Examples of the display panel in the present disclosure include display panels used in display devices such as liquid crystal display devices, organic EL display devices, and LED display devices.

[0126] The display device according to the present disclosure may have a touch panel member between the display panel and the glass substrate or glass laminate.

[0127] The display device according to the present disclosure is preferably a flexible display. In particular, the display device according to the present disclosure is preferably foldable. That is, the display device according to the present disclosure is more preferably a foldable display. The display device according to the present disclosure has the above-described glass substrate or glass laminate, and therefore has excellent impact resistance and bending resistance, and is suitable as a flexible display, and further as a foldable display.

[0128] In particular, the display device according to the present disclosure is preferably foldable so that the first main surface of the glass substrate faces outward. As described above, when the display device is folded so that the first main surface of the glass substrate faces outward, the bending resistance is higher than when the display device is folded so that the second main surface of the glass substrate faces outward.

[0129] D.Electronic equipment An electronic device according to the present disclosure includes the display device described above.

[0130] The electronic devices in the present disclosure are not particularly limited as long as they are equipped with the above-mentioned display devices, and examples thereof include smartphones, tablet devices, wearable devices, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays.

[0131] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0132] The present disclosure will be further described below with reference to examples and comparative examples.

[0133] [Example 1] A chemically strengthened glass substrate having a thickness of 70 μm was scribed using a cutter ("SOLID-D" manufactured by Mitsubishi Diamond Industrial Co., Ltd.) and then broken to be cut into pieces measuring 100 mm x 20 mm, thereby obtaining glass substrates.

[0134] [Example 2] A chemically strengthened glass substrate having a thickness of 50 μm was scribed using a cutter ("SOLID-D" manufactured by Mitsubishi Diamond Industrial Co., Ltd.) and then broken to be cut into pieces measuring 100 mm x 20 mm, thereby obtaining glass substrates.

[0135] [Example 3] A glass substrate was obtained in the same manner as in Example 1, except that a chemically strengthened glass substrate having a thickness of 30 μm was used.

[0136] [Example 4] A glass substrate was obtained in the same manner as in Example 1, except that the pressure applied during scribing with the cutter was increased by 1.5 times.

[0137] [Example 5] A glass substrate obtained in the same manner as in Example 1 was subjected to a processing step (special polishing treatment using particles with a particle diameter of 1 μm) to adjust the width a and length b.

[0138] [Example 6] A glass substrate was obtained in the same manner as in Example 1, except that the pressure applied during scribing with the cutter was increased by 2.5 times.

[0139] [Example 7] A glass substrate was obtained in the same manner as in Example 5, except that the special polishing time was set to 0.4 times the special polishing time of Example 5.

[0140] [Example 8] A glass substrate was obtained in the same manner as in Example 1, except that untempered glass was used.

[0141] [Example 9] A glass substrate was obtained in the same manner as in Example 2, except that the pressure applied when scribing with a cutter was reduced by 1 / 6.

[0142] [Comparative Example 1] A 70 μm thick glass substrate was scribed using a cutter ("Glass Scriber Cutter Tip" manufactured by Kosaka Laboratory Co., Ltd.) with a push-in depth of 0.1 mm and a speed of 20 mm / sec, and then broken to be cut into pieces measuring 100 mm x 20 mm. The glass substrate was then subjected to a chemical strengthening treatment.

[0143] Comparative Example 2 A chemically strengthened glass substrate with a thickness of 70 μm was cut into pieces of 100 mm × 20 mm by scribing and breaking under the same conditions as in Comparative Example 1. Thereafter, the cut surface of the chemically strengthened glass substrate was polished with abrasive paper containing an abrasive with a grain size of 15 μm, and then polished with diamond abrasive grains with a grain size of 1 μm.

[0144] Comparative Example 3 A 70 μm thick chemically strengthened glass substrate was cut into 100 mm × 20 mm pieces using a picosecond laser with a pulse energy of 80 μJ and an oscillation frequency of 150 kHz. Then, a resist was applied to the surface of the chemically strengthened glass substrate, and the cut surface of the chemically strengthened glass substrate was etched with a hydrogen fluoride solution.

[0145] [Rating 1] (1) Shape The cut surfaces of the glass substrates were observed at a magnification of 20,000 times using a scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, "S-4800"), and the side surface shapes were measured. The glass substrates of Examples 1 and 2 and Comparative Example 1 had a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, and the side surface had an inclined portion connecting to the first main surface and a flat portion connecting the inclined portion and the second main surface. In addition, in the glass substrates of Examples 1 and 2, the inclined portion of the side surface had a curved surface that was convex outward. The glass substrate of Comparative Example 2 had a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first main surface and the second main surface, and the side surface was flat. The glass substrate of Comparative Example 3 had a first main surface, a second main surface opposite the first main surface, and a side surface connecting the first and second main surfaces, and the side surface had a first inclined portion connecting to the first main surface, a second inclined portion connecting to the second main surface, and a flat portion connecting the first and second inclined portions, and the end of the glass substrate had a tapered shape.

[0146] (2) Maximum height Sz The maximum side height Sz of the glass substrate was measured using a non-contact surface / layer cross-sectional shape measurement system, VertScan2.0 R5500GML-A150-AC, manufactured by Ryoka Systems Corporation. Various parameters were determined based on ISO 25178, and measurements were taken at 10 random locations, and the arithmetic mean value was calculated. The measurement conditions were as follows. The 10 random locations were selected from areas that excluded the top and bottom 20% of the glass substrate in the thickness direction and were free of dust and dirt. Measurement area: 0.02mm x 0.02mm Objective lens: 50x Measurement mode: Wave Wavelength filter: 530 white Height analysis mode: pv mode

[0147] The measurement is carried out by the following method. As shown in FIG. 14, first, a glass substrate 101 is fixed by being sandwiched between two jigs 100, 100 on a stage S. Next, a lens 102 equipped with a light source is placed directly above the side surface of the glass substrate 101. The inclination of the stage S is adjusted so that the direction of light from the light source is perpendicular to the stage S. Finally, the height of the stage S is adjusted to adjust the distance between the lens 102 and the side surface of the glass substrate 101 to achieve focus, and then measurement is performed.

[0148] (3) U-shaped bending test The glass substrate was subjected to the U-bend test described above. The distance d between the two opposing short sides of the glass substrate was measured when cracks or breakage occurred in the glass substrate. Table 1 shows the maximum distance d between the opposing short sides of the glass substrate when cracks or breakage occurred in the glass substrate. The smaller the value, the better the bending resistance.

[0149] The results of the U-shaped bending test were evaluated according to the following criteria. A: d = less than 5 mm B: d = 5 mm or more, less than 10 mm C:d=10mm or more

[0150] In Table 1, "bent outward from the first principal surface" indicates the case where the glass substrate was folded so that the first principal surface was on the outside, and "bent within the first principal surface" indicates the case where the glass substrate was folded so that the first principal surface was on the inside. In Table 1, the values ​​in parentheses indicate the above evaluation.

[0151] (4) Dynamic bending test The glass substrate was subjected to the dynamic bending test described above to evaluate the bending resistance of the glass substrate. In this test, the distance d between the two opposing short sides of the glass substrate was 8 mm or 12 mm, and the number of repetitions was 200,000. The number of samples was 10. The pass rate was calculated using the following formula from the total number of samples (10) and the number of samples in which no cracks or breaks occurred in the glass substrate. Pass rate (%) = (number of samples with no cracks or breaks in the glass substrate) / 10 x 100

[0152] The results of the dynamic bending test were evaluated according to the following criteria. A: The pass rate is over 80%. B: The pass rate is between 60% and 80%. C: The pass rate is less than 60%.

[0153] In Table 1, "bent outward from the first principal surface" indicates the case where the glass substrate was folded so that the first principal surface was on the outside, and "bent within the first principal surface" indicates the case where the glass substrate was folded so that the first principal surface was on the inside. In Table 1, the values ​​in parentheses indicate the above evaluation.

[0154] (5) Impact resistance of the edges An impact test was performed on a glass substrate as shown in FIG. 13. First, a sample stage 31 and a rail 32 were positioned at an angle of 16° relative to the horizontal. Next, a glass substrate 1 was placed on the sample stage 31, and a weight 33 was placed on the glass substrate 1 to fix the glass substrate 1. The glass substrate 1 was fixed so that its edge protruded 2 mm from the side of the sample stage 31. Next, a 5.5 g, φ11 mm steel ball 34 was dropped from a predetermined distance L along the rail 32 to impact the side of the glass substrate 1. The maximum distance L at which the glass substrate did not crack or break was measured at the edge of the glass substrate. Note that a larger value indicates higher impact resistance. The results of the impact resistance of the edge were evaluated according to the following criteria. A: 12cm or more B: 8cm or more C: Less than 8cm

[0155] [Table 1] Generally, when a glass substrate is chemically strengthened glass, cutting results in a decrease in strength at the side of the glass substrate because no compressive stress layer is present on the side of the glass substrate. In contrast, as shown in Table 1, when the side of the glass substrate has an inclined portion connected to the first main surface, the width a of the inclined portion in the direction of the first main surface of the glass substrate is within a predetermined range, and the length b of the inclined portion in the thickness direction of the glass substrate is within a predetermined range (Examples 1 and 2), it was confirmed that the impact resistance of the edge of the glass substrate is good. Furthermore, when the maximum height Sz of the side of the glass is equal to or less than a predetermined value (Examples 1 and 2), it was confirmed that the bending resistance is good.

[0156] [Rating 2] (Maximum height Sz) The side surface of the glass substrate of Examples 1 and 2 and Comparative Example 1 was divided into ten equal parts in the thickness direction, and the regions were designated as regions 1 to 10 in order from the first main surface side to the second main surface side, and the maximum height Sz of each region was measured. The maximum heights of the first to tenth regions were designated Sz1 to Sz10 in order from the first region to the tenth region, respectively.

[0157] The maximum height Sz of each region on the side of the glass substrate was measured using a non-contact surface / layer cross-sectional shape measurement system, VertScan2.0 R5500GML-A150-AC, manufactured by Ryoka Systems Co., Ltd. Various parameters were determined based on ISO 25178, and measurements were taken at 10 random locations in each region, and the arithmetic mean value was calculated. The measurement conditions were as follows: Measurement area: 7μm x 10μm when the thickness of the glass substrate is 70μm If the thickness of the glass substrate is 50 μm, it is 5 μm x 10 μm If the thickness of the glass substrate is 30 μm, 3 μm x 10 μm Objective lens: 50x Measurement mode: Wave Wavelength filter: 530 white Height analysis mode: pv mode The measurement method was the same as in [Evaluation 1] above.

[0158] [Table 2]

[0159] In Examples 1 to 3, 7, and 9, the relationships of the following formulas (1) to (3) were satisfied. On the other hand, in Comparative Example 1, the relationships of the following formulas (1) and (2) were not satisfied. Sz1>Sz4 (1) Sz1>Sz5 (2) Sz1>Sz6 (3) [Explanation of symbols]

[0160] 1...Glass substrate 1A: First main surface of glass substrate 1B: Second main surface of glass substrate 1C: Side of glass substrate 2a … Inclined part 2b … Plane part 3...Compressive stress layer 10...Glass laminate 11, 12 ... resin layer 20…Display device 21... Display panel a … Width of the inclined portion in the direction of the first principal surface of the glass substrate b … Length of the inclined portion in the thickness direction of the glass substrate T: Thickness of the glass substrate

Claims

1. A glass substrate having a first surface, a second surface opposite to the first surface, and a side surface connecting the first surface and the second surface, The thickness of the glass substrate is 15 μm or more and 100 μm or less, the side surface has an inclined portion connected to the first surface and extending outward from an end of the first surface at an incline toward the second surface with respect to the first surface, The width of the inclined portion in the first surface direction of the glass substrate is 0.05 μm or more and 9.00 μm or less, The length of the inclined portion in the thickness direction of the glass substrate is 0.05 μm or more and 5.00 μm or less, A glass substrate, wherein a ratio (a / b) of a width a of the inclined portion in a first surface direction of the glass substrate to a length b of the inclined portion in a thickness direction of the glass substrate is 1.8 or more and 20.0 or less.

2. The glass substrate according to claim 1 , wherein the inclined portion has an outwardly convex curved surface.

3. The glass substrate according to claim 1 or 2, wherein the maximum height Sz of the side surface is 1.5 μm or less.

4. 4. The glass substrate according to claim 3, wherein when the regions formed by dividing the side surface into ten equal parts in a thickness direction are designated as a first region to a tenth region in the order from the first surface side to the second surface side, and when the maximum heights of the first region to the tenth region of the side surface are designated as Sz1 to Sz10 in the order from the first region to the tenth region, respectively, the glass substrate satisfies the relationships of the following formulas (1) to (3): Sz1>Sz4 (1) Sz1>Sz5 (2) Sz1>Sz6 (3)

5. The glass substrate according to claim 1 , wherein the side surface has a flat portion connecting the inclined portion and the second surface.

6. The glass substrate according to any one of claims 1 to 5, which is chemically strengthened glass.

7. The glass substrate according to claim 1 , which is used in a foldable display device so that the first surface of the glass substrate faces outward.

8. The glass substrate according to any one of claims 1 to 7, a resin layer disposed on at least one of a first surface side and a second surface side of the glass substrate; A glass laminate comprising:

9. The glass laminate according to claim 8 , wherein the resin layer is disposed on the second surface side of the glass substrate.

10. 10. The glass laminate according to claim 8 or claim 9, which has a total light transmittance of 85% or more and a haze of 1.5% or less.

11. A display panel; a glass substrate according to any one of claims 1 to 7 or a glass laminate according to any one of claims 8 to 10, which is disposed on a viewer side of the display panel; A display device comprising:

12. The display device according to claim 11 , which is foldable so that the first surface of the glass substrate faces outward.

13. An electronic device comprising a display device according to claim 11 or claim 12.

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