Glass article, display device, method for manufacturing glass article, and method for manufacturing display device

Abstract

The present invention inhibits cover glass from deviating from a desired shape. A glass article (10) according to the present invention has: heat-molded cover glass (12) including a curved part (20); a frame (14) provided to a main surface (12B) of the cover glass (12); and an adhesive layer (16) which is provided between the main surface (12B) of the cover glass (12) and the frame (14) and adhesively joins the cover glass (12) and the frame (14), wherein the parameter A stated in the specification is greater than 0 and equal to or less than 0.5.

Description

Glass article, display device, method for manufacturing a glass article, and method for manufacturing a display device

[0001] The present invention relates to a glass article, a display device, a method for manufacturing a glass article, and a method for manufacturing a display device.

[0002] Liquid crystal displays and organic EL displays are sometimes used in in-vehicle display devices that display information necessary while driving. These displays may be provided with a cover glass to protect the front surface. In recent years, high design quality has been required for vehicle interiors, creating a demand for curved cover glass. For example, Patent Document 1 describes a curved display device that includes a protective member serving as the cover glass, a frame, and a display panel. A known method for curving the cover glass is called thermoforming, in which the cover glass is heated and curved.

[0003] Japanese Patent No. 6941930

[0004] However, when the cover glass is curved by, for example, heat forming, the shape of the cover glass may deviate from the desired curved shape. Therefore, there is a need to prevent the cover glass from deviating from the desired shape.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a glass article, a display device, a method for manufacturing a glass article, and a method for manufacturing a display device that can suppress deviation of the cover glass from the desired shape.

[0006] The glass article according to the present disclosure comprises a heat-formed cover glass including a curved portion, a frame provided on a main surface of the cover glass, and an adhesive layer provided between the main surface of the cover glass and the frame to bond the cover glass and the frame, wherein a parameter A defined by the following formula (1) is greater than 0 and not more than 0.5.

[0007]

[0008] Here, E １ is the Young's modulus of the cover glass (GPa), and t １is the thickness of the cover glass (mm), and E ２ is the Young's modulus of the frame (GPa), and I ２ is the second moment of area of ​​the frame (mm ４ ) and E ３ is the modulus of elasticity of the adhesive layer (MPa), and W is the area of ​​the adhesive layer (cm ２ ) divided by the length (cm) along the main surface in a direction perpendicular to the bending axis of the curved portion.

[0009] A display device according to the present disclosure includes a display and the glass article provided on a surface of the display.

[0010] The method for manufacturing a glass article according to the present disclosure includes a step of forming a cover glass including a curved portion by heating and curving a glass plate, and a step of manufacturing a glass article by adhering a main surface of the cover glass to a frame via an adhesive layer.

[0011] The method for manufacturing a display device according to the present disclosure includes a step of attaching the glass article to a display to manufacture a display device.

[0012] According to the present invention, deviation of the cover glass from the desired shape can be suppressed.

[0013] FIG. 1 is a schematic diagram showing a display device according to the present embodiment. FIG. 2 is a schematic diagram of a glass article according to the present embodiment. FIG. 3A is a top view of a cover glass. FIG. 3B is a cross-sectional view taken along line A-A of FIG. 3A. FIG. 4 is a cross-sectional view of a glass article including a cover glass. FIG. 5 is a schematic diagram illustrating a method for manufacturing a glass article and a display device according to the present embodiment. FIG. 6 is a diagram showing an example in which a plurality of adhesive layers are provided. FIG. 7 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 8 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 9 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 10 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 11 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 12 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 13 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 14 is a schematic diagram of a cover glass according to another example of the present embodiment. FIG. 15 is a schematic diagram of a cover glass according to another example of the present embodiment. Fig. 16 is a schematic diagram of a cover glass according to another example of this embodiment, Fig. 17 is a schematic diagram of a cover glass according to another example of this embodiment, and Fig. 18 is a schematic diagram of a cover glass according to another example of this embodiment.

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations that are made by combining the respective embodiments. Furthermore, numerical values ​​include the range of rounding.

[0015] (Display Device) FIG. 1 is a schematic diagram showing a display device according to the present embodiment. As shown in FIG. 1, a glass article 10 according to the present embodiment is provided in a display device 2 and is used as a cover material for the surface (front) of a display 3 on which an image is displayed. In the present embodiment, the display device 2 is an in-vehicle display device provided in a vehicle, and is provided, for example, in front of a steering shaft 1 inside the vehicle. The display 3 displays, for example, a car navigation screen, various meters such as a speedometer, and a start button. However, the configuration in FIG. 1 is only an example, and the display device 2 to which the glass article 10 is applied may have any configuration. Furthermore, the glass article 10 is not limited to being used as a cover material for the surface of the display device 2, and may be used for any purpose.

[0016] (Glass Article) FIG. 2 is a schematic diagram of a glass article according to this embodiment. As shown in FIG. 2, the glass article 10 includes a cover glass 12, a frame 14, and an adhesive layer 16. The cover glass 12 is a transparent, plate-shaped glass member having a main surface 12A (first main surface) that is a main surface on one side, and a main surface 12B (second main surface) that is a main surface opposite to the main surface 12A. When the glass article 10 is mounted on a mounting object such as a display device 2, the main surface 12A is the side exposed to the outside, and the main surface 12B is the side facing the mounting object (here, the display 3). Note that "transparent" here refers to being transparent to visible light.

[0017] (Frame) The frame 14 is a frame-shaped member attached to the main surface 12B of the cover glass 12. The frame 14 is made of, for example, resin, metal, or fiber-reinforced plastic, but is not limited thereto and may be formed of any material. The cover glass 12 is curved in the X direction (described below), and the frame 14 is also curved in the X direction along the cover glass 12. The frame 14 is attached to the peripheral portion of the main surface 12B of the cover glass 12. In the example of FIG. 2, the frame 14 is frame-shaped and extends over the entire peripheral portion of the main surface 12B of the cover glass 12 in the circumferential direction. In addition, in the example of FIG. 2, the peripheral edge of the cover glass 12 does not protrude from the frame 14. However, this is not limited thereto and the peripheral edge of the cover glass 12 may protrude from the frame 14. The shape of the frame 14 and the attachment position of the frame 14 on the main surface 12B are not limited to those described above and may be arbitrary. For example, frame 14 may be provided in a shape that is interrupted in a partial section in the circumferential direction of the peripheral edge portion of main surface 12 B. That is, for example, if main surface 12 B has a curved rectangular shape, frame 14 may be provided on three of the four sides of the rectangle, on two opposing sides, or on one side.

[0018] (Adhesive Layer) The frame 14 is fixed (bonded) to the main surface 12B of the cover glass 12 via an adhesive layer 16. The adhesive layer 16 is provided between the frame 14 and the main surface 12B of the cover glass 12, and bonds the surface of the frame 14 facing the cover glass 12 to the main surface 12B of the cover glass 12. The adhesive layer 16 may be composed of any adhesive material capable of bonding the frame 14 and the cover glass 12 together, such as double-sided tape or adhesive.

[0019] (Cover Glass) The cover glass 12 is attached to the frame 14 while being curved. In this embodiment, the cover glass 12 is heat-formed to a desired shape. The cover glass 12 is formed by bending a flat glass plate using a heat-forming method (hot-forming method), and the bent cover glass 12 is then bent without being heated and attached to the frame 14. In other words, the cover glass 12 bent by heat-forming is attached to the frame 14 without being heated further, with bending stress acting on it due to bending accompanied by elastic deformation caused by an external force. Note that heat-forming here refers to a method of bending glass by raising the temperature above the glass transition point.

[0020] The shape of the cover glass 12 will be described in more detail below. FIG. 3A is a top view of the cover glass, FIG. 3B is a cross-sectional view taken along line A-A of FIG. 3A, and FIG. 4 is a cross-sectional view of a glass article including the cover glass. In the example of FIG. 3A, the cover glass 12 has a curved rectangular flat glass plate. Hereinafter, one side (end face) of the cover glass 12 will be referred to as side face 12C1, the side opposite side face 12C1 will be referred to as side face 12C2, the other side face of the cover glass 12 will be referred to as side face 12C3, and the side opposite side face 12C3 will be referred to as side face 12C4. In the example of FIG. 3A, side faces 12C1 and 12C2 are the short sides of the rectangle, and side faces 12C3 and 12C4 are the long sides of the rectangle. Note that the cover glass 12 is not limited to a curved rectangular flat glass plate, and may be a curved glass plate of any shape. For example, the cover glass 12 may be a polygonal, circular, or elliptical flat glass plate that has been curved.

[0021] 3A is a view of the cover glass 12 as viewed from the normal direction (Z direction) of a position P on the main surface 12B of the cover glass 12, and FIG. 4 shows a cross section of the cover glass 12 along the X direction. Among the tangential directions of the main surface 12B of the cover glass 12 at any point P on the main surface 12B, a tangential direction selected so as to satisfy the following condition is defined as the X direction (first direction). Among the tangential directions of the main surface 12B at point P, a direction perpendicular to the X direction is defined as the Y direction. Furthermore, a direction perpendicular to both the X and Y directions, i.e., the normal direction (thickness direction) to position P, is defined as the Z direction. Here, the X direction refers to the direction in which the radius of curvature of the line formed by the intersection of the main surface 12B and a plane including the tangential direction and the normal direction is smallest among the tangential directions of the main surface 12B at any point P on the main surface 12B of the cover glass 12. Because the cover glass 12 of this embodiment is uniaxially bent, the X direction can be uniquely defined regardless of the position P. However, as in the later example ( FIGS. 16 and 17 ), there may be cases where a plurality of curved portions 20 are provided and the bending directions of the respective curved portions 20 intersect. In this case, the X direction may be defined for each curved portion 20. That is, among the tangent directions at position P on one curved portion 20, the direction in which the radius of curvature of the line formed by the intersection of a plane including the tangential direction and the normal direction with the main surface 12B is the smallest may be defined as the X direction of that curved portion 20, and the X direction may be defined similarly for each curved portion 20. Note that, if there are a plurality of tangent directions in which the radius of curvature of the line formed by the intersection of a plane including the tangential direction and the normal direction with the main surface 12B is the smallest, at least one of these tangential directions may be defined as the X direction.

[0022] As shown in FIG. 4 , when the cover glass 12 is attached to the frame 14, the cover glass 12 is curved with a curvature radius R, with the Y direction as the bending axis and the X direction as the direction perpendicular to the bending axis. The curvature radius R can also be considered as the radius of curvature of a line formed by the intersection of a plane including the X and Z directions with the main surface 12B. The curvature radius R of the cover glass 12 (the curvature radius of the bending with the Y direction as the bending axis) is preferably 100 mm or more and 8000 mm or less, more preferably 300 mm or more and 6000 mm or less, and even more preferably 500 mm or more and 4000 mm or less. Having the curvature radius R within this range improves the design and prevents the cover glass 12 from deviating from the desired shape of the glass article. Furthermore, the curvature radius R1 is the curvature radius of the bending with the Y direction as the bending axis of the cover glass 12 when the cover glass 12 is removed from the frame 14. The radius of curvature R1 can also be said to be the radius of curvature of a line formed by the intersection of a plane including the X and Z directions with the main surface 12B when the cover glass 12 is removed from the frame 14. In this case, the radius of curvature R1 of the cover glass 12 is preferably 50 mm or more and 10,000 mm or less, more preferably 100 mm or more and 8,000 mm or less, and even more preferably 300 mm or more and 6,000 mm or less. Having the radius of curvature R1 within this range improves the design while preventing the cover glass 12 in the glass article from deviating from its desired shape. Note that the radius of curvature R1 refers to the radius of curvature of the cover glass 12 when the cover glass 12 is removed from the frame 14, is not subjected to an external load, and is not elastically deformed by an external load. As such, because the cover glass 12 is heat-formed, it is curved even when the cover glass 12 is removed from the frame 14 and is not elastically deformed.

[0023] More specifically, the cover glass 12 is curved by heat-forming the glass plate to the desired shape before attachment to the frame 14. At this time, the absolute value of the difference between the radius of curvature R1 of the cover glass 12 when the cover glass 12 is removed from the frame 14 and the radius of curvature R of the cover glass 12 when the cover glass 12 is attached to the frame 14 is preferably 5% or less, more preferably 2% or less, of the radius of curvature R. That is, the cover glass 12 in this embodiment is preferably bent by heat-forming to a radius of curvature close to the final radius of curvature R. This satisfies the formula (1) described below, making it easier to suppress deviation of the cover glass from the desired shape in the glass article. Meanwhile, the absolute value of the difference between the radius of curvature R1 and the radius of curvature R is, for example, greater than 0.0% and 0.2% or greater. In heat-forming methods, particularly gravity-forming methods in which a glass plate is placed on a lower mold, heated, and curved by its own weight, deviations in shape may occur even when the glass plate is bent to the desired shape. Even in such a case, according to this embodiment, when a glass article is manufactured by using a glass plate as the cover glass 12 and attaching a frame 14, deviation of the cover glass 12 from the desired shape can be prevented.

[0024] Furthermore, when the radius of curvature of the frame 14 when the cover glass 12 is removed from the frame 14 is R3, the radius of curvature R3 (the radius of curvature of the bend with the Y direction as the bending axis) is preferably 100 mm or more and 8000 mm or less, more preferably 300 mm or more and 6000 mm or less, and even more preferably 500 mm or more and 4000 mm or less. The absolute value of the difference between the radius of curvature R3 and the radius of curvature R of the cover glass 12 when the cover glass 12 is attached to the frame 14 is preferably 2% or less, more preferably 1% or less. Having the radius of curvature R3 in the above range makes it easier to prevent the cover glass in the glass article from deviating from the desired shape.

[0025] It is preferable that the cover glass 12 is not bent in any direction other than the bending direction with the Y direction as the bending axis. It is preferable that the cover glass 12 is not bent with the X direction as the bending axis, in other words, it is preferable that the locus along the Y direction on the main surface 12B of the cover glass 12 is linear. Note that "not having a bend" does not necessarily mean that the radius of curvature is infinite, but may also mean that the radius of curvature is greater than 10,000 mm.

[0026] Hereinafter, the portion of the cover glass 12 that is bent with the Y direction as the bending axis will be referred to as the curved portion 20. The curved portion 20 refers to a region of the cover glass 12 that is bent with the same radius of curvature R around the Y direction as the bending axis. In other words, it can be said that the curved portion 20 of the cover glass 12 is bent with the radius of curvature R around the Y direction as the bending axis. In the example of FIG. 4 , the entire cover glass 12 is bent with the same radius of curvature R in the X direction, so it can be said that the entire cover glass 12 forms the curved portion 20. Note that the same radius of curvature R here does not necessarily mean that the radius of curvature R is strictly the same at each position. For example, if the change in the measured radius of curvature R at each position from one end point to the other end point in the X direction in a region on the main surface 12B of the cover glass 12 that is bent with the Y direction as the bending axis is 5% or less, i.e., if the difference between the maximum and minimum values ​​of the radius of curvature R at each position is 5% or less of the maximum value of the radius of curvature R at each position, the region is considered to be a region with the same radius of curvature and treated as a single curved portion 20. Note that the average value of the radii of curvature R at each position in the curved portion 20 may be treated as the radius of curvature R of the curved portion 20. Methods for measuring the radius of curvature R and the radius of curvature R1 of the cover glass 12 include a method of measuring the shape using a contact or non-contact three-dimensional measuring device and determining the value from the shape data, and a method of measuring by pressing an R ruler against the cover glass 12.

[0027] In this embodiment, the curved portion 20 is curved so as to be convex toward the main surface 12A. However, the curved portion 20 is not limited to being curved so as to be convex toward the main surface 12A, and may be curved so as to be convex toward the main surface 12B.

[0028] The arbitrary point P may be an arbitrary point in the curved portion 20 of the main surface 12B, and may be the center position of the main surface 12B (e.g., the center of gravity of the cover glass 12) when the central region of the main surface 12A is the curved portion 20. In other words, the X and Y directions may be tangential directions from the center of the main surface 12B, and the Z direction may be a normal direction at the center of the main surface 12B.

[0029] (Cover Glass Material) The glass material for the cover glass 12 is not particularly limited, but examples thereof include alkali-free glass, soda-lime glass, soda-lime silicate glass, aluminosilicate glass, borosilicate glass, lithium aluminosilicate glass, and borosilicate glass. The cover glass 12 is preferably chemically strengthened, i.e., preferably has a compressive stress layer on its surface. Therefore, the cover glass 12 is preferably made of aluminosilicate glass or lithium aluminosilicate glass, which can easily undergo a large stress treatment even when thin, resulting in high-strength glass despite its thinness. Chemical strengthening is typically performed by immersing the glass in a molten salt containing an alkali metal.

[0030] The cover glass 12 contains, in mole percent on an oxide basis, SiO ２ 50 to 80%, Al ２ O ３ 0.1 to 25%, Li ２ O + Na ２ O+K ２ O 3 to 30%, MgO 0 to 25%, CaO 0 to 25% and ZrO ２ It is preferable that the content of Li is 0 to 5%, but there is no particular limitation. Note that 50% to 80% here means that the content is 50% or more and 80% or less when the total mole percentage of the cover glass 12 is 100%, and the same applies to other numerical ranges. ２ O + Na ２ O+K ２ O is Li ２ O and Na ２ O and K ２It refers to the total content of SiO and O. By making the cover glass 12 have the following composition, it is possible to maintain appropriate rigidity even when the cover glass 12 is bent. Note that a numerical range expressed as "to" means a numerical range that includes the numerical values ​​before and after "to" as the lower and upper limits, and the same meaning will be used hereinafter when "to" is used.

[0031] More specifically, the following glass compositions are preferred for the glass for the cover glass 12. For example, "containing 0 to 25% MgO" means that MgO is not essential but may be contained up to 25%. Glass (i) is included in soda lime silicate glass, glasses (ii) and (iii) are included in aluminosilicate glass, and glasses (iv), (v), and (vi) are included in lithium aluminosilicate glass. (i) Composition expressed in mol %, SiO ２ 63 to 73%, Al ２ O ３ 0.1 to 5.2%, Na ２ O 10-16%, K ２ 0 to 1.5% O, Li ２ (ii) a glass containing 0 to 5.0% of O, 5 to 18% of MgO, and 1 to 10% of CaO, the composition of which, expressed in mole percent, is SiO ２ 50 to 74%, Al ２ O ３ 5 to 15%, Na ２ O 10-20%, K ２ O 0-8%, Li ２ O 0 to 5.0%, MgO 2 to 15%, CaO 0 to 6% and ZrO ２ Contains 0 to 5% of SiO ２ and Al ２ O ３ The total content of 65-85%, Na ２ O and K ２ (iii) A glass having a composition expressed in mol % of SiO ２ 68 to 80%, Al ２ O ３ 4-10%, Na ２ O 5-15%, K ２O 0-1%, Li ２ O 0 to 5.0%, MgO 4 to 15% and ZrO ２ (iv) a glass containing 0 to 1% of SiO ２ 67 to 75%, Al ２ O ３ 0-4%, Na ２ O 7-15%, K ２ O 1 to 9%, Li ２ O 0 to 5.0%, MgO 6 to 14% and ZrO ２ Contains 0 to 1.5% of SiO ２ and Al ２ O ３ The total content of 71-75%, Na ２ O and K ２ (v) A glass having a composition expressed in mol % of SiO ２ 50 to 73%, Al ２ O ３ 5 to 20%, B ２ O ３ 0 to 6%, P ２ O ５ 0 to 10%, Li ２ 4-12% O, Na ２ O 3-20%, K ２ O 0-5%, MgO 0-8%, CaO 0-2%, SrO 0-5%, BaO 0-5%, ZnO 0-5%, TiO ２ 0 to 2%, ZrO ２ (vi) a glass having a composition expressed in mol % of SiO ２ 58 to 80%, Al ２ O ３ 13-18%, B ２ O ３ 0 to 5%, P ２ O ５ 0.5-4%, Li ２ 3-10% O, Na ２ O 5-20%, K ２ O 0-2%, MgO 0-11%, CaO 0-20%, SrO 0-20%, BaO 0-15%, ZnO 0-10%, TiO ２ 0 to 1%, ZrO２ Glass containing 0 to 2%

[0032] (Parameter A of Glass Article) Here, when attempting to obtain a desired curved shape by bending a glass plate by heat forming, the shape may deviate from the desired curved shape. In contrast, in the present embodiment, the glass plate is heat formed to a certain degree, and then attached to a frame 14 and further curved to produce a glass article, thereby suppressing deviation of the cover glass 12 from the desired curved shape. Furthermore, the present inventors have found that deviation from the desired curved shape can be suitably suppressed by designing the parameter A, defined as described below, to be within a predetermined numerical range. That is, in the present embodiment, deviation from the desired curved shape can be suitably suppressed by defining the parameter A of the glass article 10 as follows. Parameter A will be described below.

[0033] The parameter A of the glass article 10, as shown in the following formula (1), is 0.5 or less, preferably 0.3 or less, and more preferably 0.1 or less. By setting the parameter A within this range, deviation from the desired curved shape can be suitably suppressed. Furthermore, the parameter A is preferably greater than 0 and greater than 0.001, more preferably greater than 0.005, and even more preferably greater than 0.01. That is, the parameter A is greater than 0 and less than 0.5, preferably greater than 0.001 and less than 0.5, more preferably greater than 0.005 and less than 0.3, and even more preferably greater than 0.01 and less than 0.1. By setting the parameter A to 0.5 or less, preferably 0.3 or less, and more preferably 0.1 or less, the value PV described below can be set to 0.5 or less, and deviation from the desired curved shape can be suitably suppressed, which is preferable. Note that the value PV of the glass article 10 in this embodiment is calculated based on the following assumptions. First, let's assume that glass article 10 and a glass article having a desired curved shape are placed on a horizontal surface without any external force. In this state, the two shapes are overlapped, and the vertical distance at the point where misalignment occurs is calculated, and the maximum value over the entire area is designated as the value PV. At this time, the glass article is placed so that the convex surface is on the horizontal surface. If the glass article has both a convex and a concave surface, the larger of the vertical distance calculated when one surface is placed on the horizontal surface and the vertical distance calculated when the other surface is placed on the horizontal surface is used as the value PV.

[0034]

[0035] Here, E １ is the Young's modulus (GPa) of the cover glass 12, and t １ is the thickness (mm) of the cover glass 12, and E ２ is the Young's modulus (GPa) of the frame 14, and I ２ is the second moment of area of ​​the frame 14 (mm ４ ) and E ３ is the modulus of elasticity (MPa) of the adhesive layer 16, and W is the area B (cm ) of the adhesive layer 16 as shown in the following equation (2): ２) divided by the length L (cm) in the direction perpendicular to the bending axis of the bending portion 20. The area B and length L will be described later. ３ When a plurality of adhesive layers 16 are provided as described later (for example, FIG. 6), the thickness (E ３ When there is one adhesive layer 16, it refers to the total value of Σ(E ３ W) is the thickness of the adhesive layer 16 (E ３ W).

[0036]

[0037] In this way, the Young's modulus E of the cover glass 12 is set so that the parameter A falls within the above range. １ and thickness t １ and the Young's modulus E of the frame 14 ２ and moment of inertia I ２ and the elastic modulus E of the adhesive layer 16 ３ and the value W (area B of the adhesive layer 16 and length L of the curved portion 20), deviation from the desired curved shape can be suppressed. １ t １ ２ is a parameter indicating the rigidity of the cover glass 12, and in order to suppress deviation from the desired curved shape, that is, to lower the parameter A, it is preferable that the value of E is low. ２ I ２ is a parameter indicating the rigidity of the frame 14, and the higher the value, the easier it is to correct deviation of the cover glass 12 from the desired curved shape. Therefore, in order to suppress deviation from the desired curved shape, a higher value is preferable. Similarly, the elastic modulus E of the adhesive layer 16 ３ The higher the value of , the easier it is to transmit the correction of the frame 14 to the cover glass 12, and the higher the value of W, the easier it is to apply the correction of the frame 14 to a wider area of ​​the cover glass 12, so it can be said that higher values ​​of these are preferable in order to suppress deviation from the desired curved shape.

[0038] Each parameter defined in equations (1) and (2) will be explained below.

[0039] (Young's modulus of cover glass E １ ) Young's modulus E of the cover glass 12 １ is preferably 60 GPa or more and 90 GPa or less, more preferably 68 GPa or more and 78 GPa or less, and even more preferably 72 GPa or more and 76 GPa or less. １ When the Young's modulus E of the cover glass is in this range, deviation from the desired curved shape can be appropriately suppressed. １ can be measured by the resonance method, mechanical testing method, ultrasonic pulse method, etc. The resonance method is a method in which a test piece is vibrated to measure its natural frequency, and Young's modulus is calculated from this natural frequency. The mechanical testing method is a method in which a load such as tension is applied to the test piece, and Young's modulus is calculated from the resulting deformation and load. The ultrasonic pulse method is a method in which an ultrasonic pulse is propagated through the test piece, and measurement is made from the propagation speed. It is generally known that the Young's modulus of glass follows the additivity law, and it can also be calculated by multiple regression from the Young's moduli of multiple glass compositions.

[0040] (Cover glass thickness t １ ) Thickness t of the cover glass 12 １ The thickness t is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.4 mm or more and 1.5 mm or less, and even more preferably 0.7 mm or more and 1.4 mm or less. １ When the thickness t is in this range, deviation from the desired curved shape can be appropriately suppressed. １ indicates the distance in the Z direction from the main surface 12A to the main surface 12B.

[0041] (Young's modulus of the frame E ２ ) Young's modulus E of frame 14 ２ is preferably 1 GPa or more and 400 GPa or less, more preferably 2 GPa or more and 250 GPa or less, even more preferably 40 GPa or more and 230 GPa or less, and even more preferably 60 GPa or more and 210 GPa or less. ２When the Young's modulus E of the frame 14 is within this range, the rigidity of the frame 14 can be ensured, and the deviation of the cover glass 12 from the desired curved shape can be appropriately suppressed. ２ is Young's modulus E １ Similarly, it can be measured by the resonance method, mechanical testing method, ultrasonic pulse method, etc.

[0042] (frame second moment of area I ２ ) moment of inertia I of the frame 14 ２ is 0.1 mm ４ 1250mm or more ４ Preferably, it is 1 mm or less. ４ Over 450mm ４ More preferably, it is 1.5 mm or less. ４ 30mm or more ４ It is more preferable that the second moment of area I ２ By keeping the value in this range, the rigidity of the frame 14 can be ensured and deviation from the desired curved shape can be appropriately suppressed without significantly impairing the design. The second moment of area is relative to the bending axis. In the example of FIG. 3A, the bending axis is the Y axis, and FIG. 3B shows a cross-sectional view of the glass article 10 at the A-A cross section (a plane perpendicular to the X axis) shown in FIG. 3A. For convenience of explanation, FIG. 3B is a diagram assuming that the glass article 10 is not curved. In this case, the second moment of area I of the frame 14 is ２ As shown in FIG. 3B, in the AA cross section (plane perpendicular to the X axis), t ２ (the square of the thickness t of the frame 14) is integrated by the area FA of the frame 14 in a plane perpendicular to the X axis. More specifically, the second moment of area I ２ is the length along the main surface of the frame 14 in the direction perpendicular to the bending axis (here, the X direction), and L is the length along the main surface of the frame 14 in the direction perpendicular to the bending axis (here, the X direction). ＦＡ In this embodiment, the average value of the second moment of area for each position in the direction along the bending axis of the frame 14 is calculated as the second moment of area I ２When calculating the average value of the moment of inertia for each position in the direction along the bending axis, the distance between positions and the number of positions used to calculate the average value may be arbitrary.

[0043]

[0044] (Elastic modulus of adhesive layer E ３ ) Elastic modulus E of adhesive layer 16 ３ The modulus of elasticity is preferably 0.2 MPa or more and 100 MPa or less, more preferably 1 MPa or more and 50 MPa or less, and even more preferably 5 MPa or more and 35 MPa or less. When the modulus of elasticity is within this range, the cover glass 12 can be properly adhered to the frame 14, and the shape of the cover glass 12 can be properly conformed to the shape of the frame 14, thereby properly preventing the cover glass 12 from deviating from the desired curved shape.

[0045] The elastic modulus E of the adhesive layer 16 ３ The modulus of elasticity can be measured by the indentation modulus test described below. The adhesive layer 16 bonded to the main surface 12B of the cover glass 12 is exposed facing vertically upward and placed in a creep meter (e.g., Yamaden Model No. RE2-33005C). A plunger (Yamaden Cylindrical Plunger Model No. P-61, φ1.5, H40) is pressed into the adhesive layer 16 at a rate of 0.05 mm / sec at room temperature (e.g., 20°C) until the plunger reaches a depth of 5% to 10% of the thickness of the adhesive layer 16. The load acting on the plunger and the displacement of the plunger in the pressing direction are sequentially measured, and the load and displacement are plotted over time. The slope of the approximation line for each plotted point is calculated as the modulus of elasticity of the adhesive layer 16. Note that the indentation modulus test of the present invention is a parameter indicating adhesive strength. Although a cross adhesive strength test is known as an existing adhesive strength test, this method has been difficult to use depending on the state of the glass article. The indentation elastic modulus test can be used to verify glass articles in which the cover glass and frame are bonded, and it correlates with the adhesive strength observed in existing adhesive strength tests.

[0046] (Area B of Adhesive Layer) As shown in FIG. 3A , the area B of the adhesive layer 16 refers to the area of ​​the adhesive region AR, which is the area that overlaps with the adhesive layer 16, within the entire area of ​​the main surface 12B of the curved portion 20. The area B of the adhesive layer 16 is 50 cm ２ More than 1700cm ２ Preferably, it is less than 100 cm ２ More than 1400cm ２ More preferably, it is 200 cm or less. ２ More than 1100cm ２ It is even more preferable that the area B is less than or equal to 1 / 2 mm. Having the area B within this range prevents the design from being adversely affected by an excessively large adhesive area AR, while allowing the cover glass 12 to be properly adhered to the frame 14. This allows the shape of the cover glass 12 to properly conform to the shape of the frame 14, thereby preventing the cover glass 12 from deviating from the desired curved shape. When multiple adhesive layers 16 are provided, the area B of each adhesive layer 16 refers to the area of ​​one of the adhesive layers 16. If the area AR0 is defined as the area of ​​the entire main surface 12B of the curved portion 20 that does not overlap with the adhesive layer 16, the adhesive area AR is formed radially outward of the area AR0 when the axis passing through the center position of the curved portion 20 along the Z direction is defined as the axial direction. In this embodiment, the entire cover glass 12 constitutes the curved portion 20, and therefore the area AR is defined as the area of ​​the entire main surface 12B of the cover glass 12 that overlaps with the adhesive layer 16. The adhesive regions AR do not have to be continuous, and a plurality of discontinuous or patchy adhesive regions AR may be formed.

[0047] (Length L of Curved Portion) The length (perimeter) L of the curved portion 20 refers to the length of the curved portion 20 along the main surface in the X direction perpendicular to the bending axis. The length L refers to the length of a line extending along the main surface 12B in the X direction, connecting an end point (position) on one side of the curved portion 20 in the X direction to an end point (position) on the other side of the curved portion 20 in the X direction. The line extending along the main surface 12B in the X direction refers to a line extending along the main surface 12B in the X direction without shifting in the Y direction. In the example of FIG. 3A , the end point on one side of the curved portion 20 in the X direction is a point on the side surface 12C1, and the end point on the other side of the curved portion 20 in the X direction is a point on the side surface 12C2, so the length L refers to the length of the line extending along the main surface 12B in the X direction from the side surface 12C1 to the side surface 12C2. The length L is preferably 100 mm or more and 2000 mm or less, more preferably 150 mm or more and 700 mm or less, and even more preferably 200 mm or more and 400 mm or less. By making the length L preferably 2000 mm or less, more preferably 700 mm or less, and even more preferably 400 mm or less, it is possible to increase W and reduce the parameter A, thereby appropriately preventing the cover glass 12 from deviating from the desired curved shape. Furthermore, by making the length L preferably 100 mm or more, more preferably 150 mm or more, and even more preferably 200 mm or more, it is possible to prevent deterioration of the design. Note that in this embodiment, even if the radius of curvature R is the same, a region where the length L is 5 mm or less (e.g., surface irregularities or fine undulations) is not considered to be the curved portion 20. In other words, a region where the radius of curvature R is the same and the length L is longer than 5 mm is considered to be the curved portion 20.

[0048] (Value W) Area B of adhesive layer 16 (cm ２ The value W obtained by dividing the width W (cm) of the curved portion 20 by the length L (cm) of the curved portion 20 is preferably 1 cm or more and 20 cm or less, and more preferably 2 cm or more and 6.2 cm or less. When the value W is within this range, deviation of the cover glass 12 from the desired curved shape can be appropriately prevented while preventing deterioration of the design.

[0049] (Method of Manufacturing Glass Article) Next, a method of manufacturing the glass article 10 will be described. FIG. 5 is a schematic diagram illustrating a method of manufacturing a glass article and a display device according to this embodiment. As shown in FIG. 5, in this manufacturing method, a flat glass plate, i.e., a cover glass 12, is heated and curved (thermally shaped) to form the cover glass 12 including the curved portion 20 (step S10). The cover glass 12 at step S10, i.e., the cover glass 12 in a state where it is not attached to the frame 14, is curved to have the above-mentioned radius of curvature R1. Next, the main surface 12B of the cover glass 12 is bonded to the frame 14 via the adhesive layer 16 to form the glass article 10 (step S12). The cover glass 12 after step S12, i.e., the cover glass 12 in a state where it is attached to the frame 14, is curved to have the above-mentioned radius of curvature R. Then, the display 3 is attached to the main surface 12B of the glass article 10, inside the adhesive region AR where the frame 14 and adhesive layer 16 are bonded (step S14). Then, the glass article 10 with the display 3 attached is attached to the housing 4 to form the display device 2 (step S16). In step S16, the display 3 is housed within the housing 4, and the glass article 10 with the display 3 attached is attached to the housing 4 so that the main surface 12A is exposed to the outside. Note that in the example of FIG. 5, the main surface 12B to which the frame 14 and the display 3 are attached is convex, and the main surface 12A exposed to the outside is concave, but this is not limited thereto. As shown in FIG. 2, the main surface 12B may be concave and the main surface 12A may be convex. Furthermore, the step of housing the display 3 in the housing 4 as in step S16 is not essential, and the glass article 10 with the display 3 attached may be treated as the display device 2.

[0050] In this manufacturing method, it is preferable to chemically strengthen the cover glass 12 after step S10. More specifically, it is preferable to chemically strengthen the heat-formed cover glass 12 after step S10, and then perform step S12 to attach the frame 14 to the chemically strengthened cover glass 12.

[0051] (Effects) As described above, the glass article 10 according to the first aspect of this embodiment includes a heat-formed cover glass 12 including a curved portion 20, a frame 14 provided on the main surface 12B of the cover glass 12, and an adhesive layer 16 provided between the main surface 12B of the cover glass 12 and the frame 14 to bond the cover glass 12 to the frame 14. The parameter A of the glass article 10 is greater than 0 and less than or equal to 0.5. The glass article 10 according to this embodiment can further curve the cover glass 12, which has been curved to a certain extent by heat forming, by bonding it to the frame 14, thereby appropriately curving the cover glass 12 to a desired shape. Furthermore, by setting the parameter A to 0.5 or less, it is possible to suppress deviation of the value PV (described below) to a level of 0.5 or less, thereby appropriately suppressing deviation of the cover glass 12 from the desired curved shape.

[0052] The glass article 10 according to a second aspect of the present embodiment is the glass article 10 according to the first aspect, wherein the absolute value of the difference between the radius of curvature R1 of the curved portion of the cover glass 12 when the cover glass 12 is removed from the frame 14 and the radius of curvature R of the curved portion of the cover glass 12 when the cover glass 12 is attached to the frame 14 is preferably 10% or less of the radius of curvature R. When the absolute value of the difference in the radii of curvature is within this range, deviation of the cover glass 12 in the glass article from the desired shape can be suppressed.

[0053] The glass article 10 according to a third aspect of the present embodiment is the glass article 10 according to the first or second aspect, and preferably has a radius of curvature R of 100 mm or more and 8000 mm or less of the curved portion 20 of the cover glass 12. Having the radius of curvature R within this range improves design while preventing the cover glass 12 from deviating from the desired shape.

[0054] The glass article 10 according to a fourth aspect of the present embodiment is the glass article 10 according to any one of the first to third aspects, wherein the thickness t of the cover glass 12 is １ is preferably greater than 1 mm. １ When the thickness falls within this range, deviation of the cover glass 12 from the desired shape can be suppressed.

[0055] The glass article 10 according to a fifth aspect of the present embodiment is the glass article 10 according to any one of the first to fourth aspects, and preferably has a radius of curvature R1 of 50 mm or more and 10,000 mm or less of the curved portion of the cover glass 12 when the cover glass 12 is removed from the frame 14. Having the radius of curvature R1 within this range improves design while appropriately suppressing deviation of the cover glass 12 from the desired shape.

[0056] The glass article 10 according to a sixth aspect of the present embodiment is the glass article 10 according to any one of the first to fifth aspects, wherein the Young's modulus E １ is 60 GPa or more and 90 GPa or less, and the Young's modulus E of the frame 14 is ２ is 1 GPa or more and 400 GPa or less, and the elastic modulus E of the adhesive layer 16 ３ is 0.2 MPa or more and 100 MPa or less, and the second moment of area I ２ is 0.1 mm ４ 1250mm or more ４ It is preferable that these parameters are within the above ranges. When these parameters are within the above ranges, deviation of the cover glass 12 from the desired shape can be appropriately suppressed.

[0057] A glass article 10 according to a seventh aspect of the present embodiment is the glass article 10 according to any one of the first to sixth aspects, and the cover glass 12 is preferably chemically strengthened. Chemical strengthening can improve the strength.

[0058] A display device 2 according to an eighth aspect of the present embodiment includes a display 3 and a glass article 10 according to any one of the first to seventh aspects provided on the surface of the display 3. This makes it possible to appropriately suppress deviation of the cover glass 12 from the desired shape.

[0059] The method for manufacturing a glass article according to a ninth aspect of the present embodiment includes a step of heating and curving a glass plate to form cover glass 12 including curved portion 20, and a step of bonding main surface 12B of cover glass 12 to frame 14 via adhesive layer 16 to manufacture glass article 10. This manufacturing method can appropriately prevent cover glass 12 from deviating from the desired shape.

[0060] A manufacturing method of a glass article according to a tenth aspect of the present embodiment is the manufacturing method of a glass article according to the ninth aspect, and preferably uses a cover glass 12, a frame 14, and an adhesive layer 16 in which the parameter A defined by formula (1) is 0.5 or less. According to this manufacturing method, by setting the parameter A to 0.5 or less, it is possible to suppress deviation of the value PV described below to a level of 0.5 or less, for example, and therefore it is possible to appropriately suppress deviation of the cover glass 12 from the desired curved shape.

[0061] A method for manufacturing a glass article according to an eleventh aspect of the present embodiment is the method for manufacturing a glass article according to the ninth or tenth aspect, and preferably further includes a step of chemically strengthening the cover glass 12 after the step of forming the cover glass 12. This manufacturing method increases the strength of the cover glass 12 and makes it possible to suppress breakage.

[0062] A method for manufacturing a display device according to a twelfth aspect of the present disclosure includes a step of attaching glass article 10 manufactured by the manufacturing method according to any one of the ninth to eleventh aspects to a display 3 to manufacture a display device 2. This manufacturing method can appropriately suppress deviation of cover glass 12 from a desired shape.

[0063] (Another Example) Next, another example of the glass article 10 according to this embodiment will be described.

[0064] (Example of Multiple Adhesive Layers) FIG. 6 is a diagram illustrating an example of providing multiple adhesive layers. In the above description, one adhesive layer 16 was provided, but multiple adhesive layers 16 may be provided. In this case, as shown in FIG. 6 , each adhesive layer 16 is adhered to the main surface 12B of the cover glass 12 at different positions from each other when viewed from the Z direction. When providing multiple adhesive layers 16, it is preferable to provide an adhesive layer 16 with a lower adhesive strength (elastic modulus) radially outward of an adhesive layer 16 with a higher adhesive strength (elastic modulus). For example, providing an adhesive layer 16 with a lower adhesive strength, such as double-sided tape, on the outside functions as a bank for the inner adhesive layer 16 (e.g., adhesive) with a higher adhesive strength, thereby preventing the adhesive from spilling outward before hardening. In the example of FIG. 6 , each adhesive layer 16 is provided with the outer peripheral edge of the inner adhesive layer 16 separated from the inner peripheral edge of the outer adhesive layer 16. However, FIG. 6 is merely an example, and the positions of each adhesive layer 16 may be set as desired. Although two adhesive layers 16 are provided in the example shown in FIG. 6, three or more adhesive layers 16 may be provided.

[0065] (Example of Spline Shape) FIG. 7 is a schematic diagram of a cover glass according to another example of this embodiment. In the above-described embodiment, the curved portion 20 has been described as a portion curved with the same radius of curvature R. However, there are also cases where the curved portion 20 is curved in the X direction along a spline curve with an inconstant radius of curvature. In such cases, the entire portion curved in the X direction along a spline curve is treated as the curved portion 20. In the description of the above-described embodiment, a region on the main surface 12B curved about the Y direction as the bending axis, in which the measured radius of curvature R varies by 5% or less at each position from one end point in the X direction to the other end point, is treated as a single curved portion 20 with the same radius of curvature. On the other hand, in this example, a region on the main surface 12B curved about the Y direction as the bending axis, in which the change in radius of curvature R varies by more than 5% at each position in a section of 50 mm or less from one end point in the X direction to the other end point, is treated as a single spline-shaped curved portion 20. 7 , the spline-shaped curved portion 20 is approximated to a shape that bends with a constant radius of curvature, and the radius of curvature when approximated to a shape that bends with a constant radius of curvature is treated as the radius of curvature R of the curved portion 20. Specifically, one end point in the X direction of the main surface 12B of the spline-shaped curved portion 20 is defined as end point 20J, the other end point is defined as end point 20K, and a plane connecting end point 20J and end point 20K and extending along the X and Y directions (i.e., an XY plane passing through end points 20J and 20K) is defined as plane α. If a plane obtained by translating plane α in the Z direction so as to be tangent to the main surface 12B is defined as plane β, the radius of curvature R of the arc 20R that passes through end points 20J and 20K and is tangent to plane β is defined as the radius of curvature R of the curved portion 20.

[0066] (Example with Flat Portion) Figures 8 and 9 are schematic diagrams of a cover glass according to another example of this embodiment. A flat portion 22 may be connected to the curved portion 20 on the X1 side. Note that the direction X1 refers to one direction along the X direction, and the direction X2 refers to the other direction along the X direction. The flat portion 22 is connected to the curved portion 20 so that the main surface 12B is continuous with (not discontinuous from) the curved portion 20. The flat portion 22 is a flat portion of the entire area of ​​the cover glass 12 that is connected to the end of the curved portion 20 on the direction X1 side. The flat portion 22 being flat does not necessarily mean that the radius of curvature is infinite, but may also mean that the radius of curvature is greater than 10,000 mm.

[0067] When a flat portion 22 is connected to the curved portion 20, the curved portion 20 and the flat portion 22 are treated as a single curved portion 20a in applying formulas (1) and (2). For example, when the flat portion 22 is provided on the X1-direction side of the curved portion 20 and the flat portion 22 is not provided on the X2-direction side as shown in FIG. 8 , the length of the curved portion 20a in the X direction, which is the bending direction (the sum of the length of the curved portion 20 in the X direction and the length F of the flat portion 22), is treated as the length L. Furthermore, the area of ​​the region of the main surface 12B of the curved portion 20a that overlaps with the adhesive layer 16 (the sum of the area of ​​the region of the main surface 12B of the curved portion 20 that overlaps with the adhesive layer 16 and the area of ​​the region of the main surface 12B of the flat portion 22 that overlaps with the adhesive layer 16) is treated as the area B. The length F of the flat portion 22 refers to the length along the main surface 12B from the end point of the flat portion 22 on the X1 side of the main surface 12B to the end point on the X2 side of the main surface 12B.

[0068] 9 , the flat portion 22 may be connected to both sides of the curved portion 20 in the X direction (both the X1-direction side and the X2-direction side). As shown in FIG. 9 , when the flat portion 22 on the X1-direction side of the curved portion 20 and the flat portion 22 on the X2-direction side have different lengths F along the main surface 12B, the curved portion 20 and the flat portion 22 with the shorter length F along the main surface 12B are treated as a single curved portion 20a. That is, the length of the curved portion 20a in the X direction (the sum of the length of the curved portion 20 and the length F of the shorter flat portion 22) is treated as the length L, and the area of ​​the region of the main surface 12B of the curved portion 20a that overlaps with the adhesive layer 16 (the sum of the area of ​​the region of the main surface 12B of the curved portion 20 that overlaps with the adhesive layer 16 and the area of ​​the region of the main surface 12B of the shorter flat portion 22 that overlaps with the adhesive layer 16) is treated as the area B. In addition, when the length F along the main surface 12B of the flat portion 22 on the X1 side of the curved portion 20 and the flat portion 22 on the X2 side are the same, the curved portion 20 and either of the flat portions 22 are treated as one curved portion 20a.

[0069] 10 and 11 are schematic diagrams of a cover glass according to another example of this embodiment. A plurality of curved portions 20 may be provided. In other words, the cover glass 12 may be formed with a plurality of curved portions 20 having different radii of curvature R. In this case, each curved portion 20 is bent around the same bending axis, that is, the Y direction. Whether there are a plurality of curved portions 20 can be determined as follows. That is, in a region on the main surface 12B that is bent around the Y direction as a bending axis, in a section longer than 50 mm from one end point on one side toward the other end point in the X direction, where the change in the radius of curvature R at each position is greater than 5%, it is determined that a plurality of curved portions 20 having different radii of curvature R are formed. That is, if the change in the radius of curvature R in a section of the main surface 12B that is bent about the Y direction as a bending axis is 5% or less in a section of 50 mm or less from one end point to the other end point in the X direction, but the change in the radius of curvature R in a section longer than 50 mm from one end point to the other end point is 5% or more, it is determined that the spline-shaped curved section does not have a single curved section, but rather multiple curved sections are formed. In this case, as shown in the example of Figure 10, a region of the main surface 12B that is bent about the Y direction as a bending axis, where the change in the radius of curvature R at each position in the section from one end point 20L to the other end point 20M in the X direction is 5% or less, is considered to be a single curved section 20A with the same radius of curvature R. The curved section 20A is the region from one end point 20L to a position 20N where the change in the radius of curvature R is greater than 5%. The region in the section from position 20N toward the other end point 20M where the change in radius of curvature R is 5% or less is defined as another curved portion 20B. In the example of FIG. 10 , the change in radius of curvature is 5% or less in the section from position 20N to end point 20M, so the region from position 20N to end point 20M is treated as curved portion 20B. However, for example, if there is a position between position 20N and end point 20M where the change in radius of curvature R is greater than 5%, the region from position 20N to the position where the change in radius of curvature R is greater than 5% is defined as one curved portion 20B. In this case, three or more curved portions 20 exist.

[0070] When a plurality of curved portions 20 are formed in this manner, Equations (1) and (2) are applied to each curved portion 20. FIG. 10 shows an example in which a curved portion 20A having a curvature radius Ra and a curved portion 20B having a curvature radius Rb are formed. In the example of FIG. 10, both curved portions 20A and 20B are convex toward the main surface 12A, but this is not limited thereto, and both curved portions 20A and 20B may be convex toward the main surface 12B. In other words, when there are a plurality of curved portions 20, each curved portion 20 is convex toward the same direction. Note that the number of curved portions 20 is not limited to two and may be three or more.

[0071] FIG. 11 shows an example in which flat portions 22 are connected to multiple bending portions 20. When flat portions 22 are connected to multiple bending portions 20, one bending portion 20 and the flat portion 22 connected to that bending portion 20 are treated as one bending portion 20a in applying Equations (1) and (2). In the example of FIG. 11, a long flat portion 22 is connected to the X2 side of bending portion 20B, a short flat portion 22 is connected to the X1 side of bending portion 20B, and bending portion 20A is connected to the short flat portion 22 on the side opposite to bending portion 20B. In this case, bending portion 20A and the short flat portion 22 are treated as one bending portion 20a, and bending portion 20B and the short flat portion 22 are treated as another bending portion 20a. The method of calculating the length L and area B of bending portion 20a is the same as when a flat portion 22 is connected to one bending portion 20, and therefore description thereof will be omitted.

[0072] 12 to 15 are schematic diagrams of cover glasses according to other examples of this embodiment. In the above-described embodiment, a rectangular glass plate was bent in the X direction to form the cover glass 12, so the length of the cover glass 12 in the X direction was constant at each position. However, depending on the shape, the length of the cover glass 12 in the X direction may vary at each position. The length L in such cases will be described below.

[0073] As described above, length L refers to the length of a line extending in the X direction on main surface 12B, connecting a position furthest to one side in the X direction (X1 direction) with respect to bending axis YA along direction Y of bending portion 20 to a position furthest to the other side in the X direction (X2 direction) with respect to bending axis YA of bending portion 20. Therefore, for example, as shown in Figure 12, when a trapezoidal glass plate is bent around the Y direction as the bending axis to form cover glass 12, both end points of side surface 12C3, which is the long side of the trapezoid, are position 20C, which is furthest to the X2 direction, and position 20D, which is furthest to the X1 side, with respect to bending axis YA of bending portion 20, and the length of the line extending in the X direction on main surface 12B, connecting position 20C and position 20D, is length L.

[0074] In the above description, the X direction perpendicular to the bending axis is aligned with the side surfaces 12C3 and 12C4, which are the horizontal sides of the flat cover glass 12 before bending. However, this is not limited thereto. The X direction perpendicular to the bending axis may be offset from (intersect with) the sides of the flat cover glass 12 before bending. Figure 13 shows an example in which the X direction intersects with the side surfaces 12C3 and 12C4 of the flat cover glass 12 before bending. In the example of Figure 13, one end point of the side surface 12C3, which is the long side of the trapezoid, is position 20C, and the other end point of the side surface 12C4, which is the short side of the trapezoid, is position 20D. In the example of Figure 13, the positions of the positions 20C and 20D are not aligned in the Y direction. Therefore, the length of the line extending in the X direction along the plane along the main surface 12B is defined as length L, connecting the position 20D', which is shifted from the position 20D in the Y direction, with the position 20C. 13 , the length of the curve connecting position 20C and position 20D' and having a radius of curvature R is length L. Note that position 20D' is a position obtained by shifting position 20D in the Y direction so that its position in the Y direction is aligned with the position of position 20C. In this way, when positions 20C and 20D are not aligned in the Y direction, the length L is the length of the line extending in the X direction along the plane along main surface 12B from position 20C, where the positions in the Y direction are aligned, to position 20D'.

[0075] 14 shows an example in which a polygonal glass plate is bent in the X direction to form cover glass 12. In the example of Fig. 14 , positions 20C and 20D, which are the points furthest in the X direction toward the X2 direction and the X1 direction, respectively, with respect to a bending axis YA along the Y direction of curved portion 20, are not aligned in the Y direction, and therefore the length of the line connecting positions 20D' and 20C and running along main surface 12B in the X direction is length L.

[0076] 15 shows an example in which a glass plate having a curved outer periphery is bent in the X direction to form cover glass 12. In the example of Fig. 15 , positions 20C and 20D, which are the points furthest in the X direction toward the X2 direction and the X1 direction, respectively, with respect to a bending axis YA along the Y direction of curved portion 20, are not aligned in the Y direction, and therefore the length of the line connecting positions 20D' and 20C and running along the plane along main surface 12B in the X direction is length L.

[0077] 16 to 18 are schematic diagrams of cover glasses according to other examples of this embodiment. In the above description, the multiple curved portions 20 are curved in the same direction with the Y direction as the bending axis, but the bending axes of the multiple curved portions 20 may be in different directions. In this case, the bending axes of the respective curved portions 20 do not intersect on the main surface 12A of the cover glass 12, but intersect at points where the bending axes of the respective curved portions 20 are extended outward from the main surface 12A.

[0078] 16 and 17 show examples of schematic diagrams of a cover glass 12 in which the bending axes of multiple curved portions 20 are different. In the example of FIG. 16 , curved portion 20A is connected to the X2-oriented side of flat portion 22, and curved portion 20B is connected to the X1-oriented side of flat portion 22. Curved portion 20A is bent around bending axis YA from side surface 12C1, which is the edge on the X2-oriented side, to edge 20P on the X1-oriented side. That is, curved portion 20A is a region bent around bending axis YA such that the change in curvature radius at each position in the X direction from side surface 12C1 to edge 20P is 5% or less. Curved portion 20B is bent around bending axis YB from edge 20Q on the X2-oriented side to edge 12C2, which is the edge on the X1-oriented side. That is, the curved portion 20B is a region that is bent around the bending axis YB so that the change in the radius of curvature at each position in the X direction from the end edge 20Q to the side surface 12C2 is 5% or less. The flat portion 22 is a flat region in the X direction from the end edge 20P to the end edge 20Q. The bending axis YA of the curved portion 20A and the bending axis YB of the curved portion 20B extend in different directions, but do not intersect on the main surface 12A of the cover glass 12. Instead, they intersect at a point where the bending axes YA and YB extend outward from the main surface 12A. Note that, for convenience of explanation, FIG. 16 illustrates the curved portion 20A as being in the Y direction, i.e., the bending axes YA and YB are in the same direction. However, in reality, the bending axes YA and YB of the curved portions 20A and 20B extend in different directions.

[0079] When a flat portion 22 is connected to multiple bending portions 20 having different bending axis directions, in applying formulas (1) and (2), one bending portion 20 and the flat portion 22 connected to that bending portion 20 are treated as one bending portion 20a. In the example of FIG. 17 , a flat portion 22 is connected to the X1-direction side of bending portion 20A, and a flat portion 22 is connected to the X2-direction side of bending portion 20B. In this case, the bending portion 20A and the flat portion 22 are treated as one bending portion 20a, and the bending portion 20B and the flat portion 22 are treated as another bending portion 20a. The method of calculating the area B for the bending portion 20a is the same as when a flat portion 22 is connected to one bending portion 20, and therefore description thereof will be omitted.

[0080] A method for calculating the length L of multiple curved portions 20 having different bending axis directions will be described with reference to FIG. 18 . For convenience of explanation, FIG. 18 illustrates a curved portion 20a including a curved portion 20A and a flat portion 22. In the example of FIG. 18 , the end point of the side surface 12C1 closest to the X2 direction is position 20C of the curved portion 20a, and the end point of the end edge 20P closest to the X1 direction is position 20D of the curved portion 20a. In the example of FIG. 20 , since the positions of position 20C and position 20D are not aligned in the Y direction, the length of the line extending in the X direction along the main surface 12B connecting position 20D', which is obtained by shifting position 20D in the Y direction, to position 20C is defined as the length L of the curved portion 20a. That is, in the example of FIG. 20 , the length of the curve connecting position 20C and position 20D' and having a radius of curvature R is defined as the length L. The length L of the curved portion 20a including the curved portion 20B and the flat portion 22 can be calculated in the same manner, but the explanation will be omitted.

[0081] Next, examples will be described. The embodiment may be modified as long as the effects of the invention are achieved. Simulation tests were conducted for each example.

[0082] (Simulation) Impact and collision analysis software using the finite element method (PAM-CRASH manufactured by Japan ESI Co., Ltd.) was used for the simulation. In the simulation, COS3D (Material Type 305), which allows the adhesive fracture energy to be set for the adhesive layer, was used, and the adhesive fracture energy EFRSn was set to match the actual test. In the simulation, first, bending elastic energy (accumulated as glass stress) was applied to the glass plate. At this time, the glass plate with an initial shape simulating the amount of bending generated by actual thermal bending was elastically corrected to an ideal shape. This allows elastic energy equivalent to the amount of bending to be accumulated as glass stress. Next, a frame was attached to the glass plate with accumulated elastic energy via the adhesive layer. The glass, adhesive layer, and frame were deformed by the elastic energy of the glass, and equilibrated in a predetermined state. The maximum difference in vertical distance between the shape in this balanced predetermined state and the ideal shape was calculated as the value PV. Note that the initial shape in the simulation could be set based on the desired elastic energy to be imparted to the glass plate, and the desired elastic energy was set to the same value in each example. Furthermore, elements in the adhesive layer whose adhesive energy exceeds the adhesive fracture energy disappear, making it possible to simulate the phenomenon of glass peeling off from the frame. It has been confirmed that there is no discrepancy between the simulation results and the results of actual tests.

[0083] (Simulation Conditions) Table 1 lists the conditions of the simulation model for each example. For example, in Example 1, a model was prepared by bonding the cover glass and the frame with one adhesive layer (first adhesive layer) so that the radius of curvature R of the cover glass was the value listed in Table 1. Similarly, in Examples 16 and 17, two types of adhesive layers (first adhesive layer and second adhesive layer) were used to bond the cover glass and the frame. The thickness t of the cover glass １ , Young's modulus E １ , the second moment of area of ​​the frame I ２ , Young's modulus E ２ , the elastic modulus E of the first adhesive layer ３ , and the elastic modulus E of the second adhesive layer ３The value W was set to the value shown in Table 1. Furthermore, the parameter A was calculated for each example. The value of the parameter A is shown in Table 1.

[0084]

[0085] (Evaluation) In the evaluation, a value PV, which is the amount of deviation of the cover glass from the desired shape, was calculated in a simulation. The value PV was calculated as described above. In the evaluation, a value PV of 0.5 or less was considered to be pass, and a value PV of more than 0.5 was considered to be fail. In Examples 1 to 3 and 5 to 18, which are working examples in which the parameter A is 0.5 or less, the value PV passed, indicating that deviation of the cover glass from the desired shape can be suppressed. On the other hand, in Examples 4 and 19, which are comparative examples in which the parameter A is more than 0.5, the value PV failed, indicating that deviation of the cover glass from the desired shape cannot be suppressed.

[0086] Although the embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0087] According to the present invention, deviation of the cover glass from the desired shape can be suppressed.

[0088] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2022-123808) filed on August 3, 2022, the contents of which are incorporated herein by reference.

[0089] REFERENCE SIGNS LIST 1 steering shaft 2 display device 3 display 4 housing 10 glass article 12 cover glass 12A, 12B main surfaces 12C1, 12C2, 12C3, 12C4 side surfaces 14 frame 16 adhesive layer 20, 20A, 20B curved portion 20a curved portion 20C, 20D, 20D', 20N position 20J, 20K, 20L, 20M end points 20P, 20Q end edges 20R arc 22 flat portion

Claims

1. a heat-formed cover glass including a curved portion; A frame provided on a main surface of the cover glass; an adhesive layer provided between a main surface of the cover glass and the frame to bond the cover glass to the frame; having A glass article, wherein a parameter A defined by the following formula (1) is greater than 0 and less than 0.

5. [0010] Where: E １ is the Young's modulus of the cover glass (GPa), t １ is the thickness of the cover glass (mm), E ２ is the Young's modulus of the frame (GPa), I ２ is the second moment of area of ​​the frame (mm ４ ) and E ３ is the elastic modulus of the adhesive layer (MPa); W is the area of ​​the adhesive layer (cm ２ ) divided by the length (cm) along the main surface in a direction perpendicular to the bending axis of the curved portion.

2. 2. The glass article according to claim 1, wherein an absolute value of a difference between a radius of curvature R1 of the curved portion of the cover glass when the cover glass is removed from the frame and a radius of curvature R of the curved portion of the cover glass when the cover glass is attached to the frame is 10% or less of the radius of curvature R.

3. 3. The glass article according to claim 1, wherein the radius of curvature R of the curved portion of the cover glass is 100 mm or more and 8000 mm or less.

4. The thickness t of the cover glass １ The glass article according to claim 1 or claim 2, wherein the thickness is greater than 1 mm.

5. 3. The glass article according to claim 1, wherein a radius of curvature R1 of the curved portion of the cover glass when the cover glass is removed from the frame is 50 mm or more and 10,000 mm or less.

6. The Young's modulus E of the cover glass １ is 60 GPa or more and 90 GPa or less, The Young's modulus E of the frame ２ is 1 GPa or more and 400 GPa or less, The elastic modulus E of the adhesive layer ３ is 0.2 MPa or more and 100 MPa or less, The second moment of area of ​​the frame I ２ is 0.1 mm ４ 1250mm or more ４ 3. The glass article according to claim 1 or 2, wherein:

7. The glass article of claim 1 or 2, wherein the cover glass is chemically strengthened.

8. A glass article as described in claim 1 or claim 2, wherein the absolute value of the difference between the radius of curvature R1 of the curved portion and the radius of curvature R of the curved portion is greater than 0.0%.

9. A glass article as described in claim 8, wherein the absolute value of the difference between the radius of curvature R1 of the curved portion and the radius of curvature R of the curved portion is 0.2% or more.

10. A display and the glass article according to claim 1 or 2 provided on a surface of the display. Display device.

11. A step of heating and curving a glass plate to form a cover glass including a curved portion; and adhering the main surface of the cover glass to a frame via an adhesive layer to produce a glass article. A method for manufacturing a glass article.

12. The method for manufacturing a glass article according to claim 11 , wherein the cover glass, the frame, and the adhesive layer are used such that a parameter A defined by the following formula (1) is 0.5 or less. [0025] Where: E １ is the Young's modulus of the cover glass (GPa), t １ is the thickness of the cover glass (mm), E ２ is the Young's modulus of the frame (GPa), I ２ is the second moment of area of ​​the frame (mm ４ ) and E ３ is the elastic modulus of the adhesive layer (MPa); W is the area of ​​the adhesive layer (cm ２ ) divided by the length (cm) along the main surface in a direction perpendicular to the bending axis of the curved portion.

13. The method for producing a glass article according to claim 11 or 12, further comprising a step of chemically strengthening the cover glass after the step of forming the cover glass.

14. The method includes the step of attaching the glass article manufactured by the method for manufacturing a glass article according to claim 11 or 12 to a display to manufacture a display device. A method for manufacturing a display device.

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