Tempered glass article

Abstract

A tempered glass article according to the present invention comprises: a tempered glass substrate subjected to a chemical strengthening treatment and having a first main surface which is a viewing surface, a second main surface, and an end surface orthogonal to the first and second main surfaces; and a protective layer provided on the end surface. The protective layer has, in a cross-sectional view orthogonal to the first main surface, a bottom edge part extending along the end surface from a first end part on the first main surface side to a second end part on the second main surface side, and an arc portion connecting the first end part and the second end part, and satisfies the following relational expressions (1) to (3).　(1): C1 / C2 ≥ 1.1 (C1: Potassium concentration of the first end part or the second end part, C2: potassium concentration of a central part in the thickness direction of the tempered glass substrate at the end surface) (2): 0.18 ≤ H / L ≤ 1.21 (H: Length from the apex of the arc portion to the end surface, L: length of the bottom edge part) (3): 40° ≤ θ1 ≤ 135° (θ1: First contact angle at the first end part side in the arc portion)

Description

tempered glass articles

[0001] The present invention relates to a tempered glass article.

[0002] For example, in fields such as cover glass for electronic devices, high strength is sometimes required for glass articles used. As a configuration applicable to such cases, Patent Document 1 discloses a tempered glass article that has been subjected to a chemical tempering treatment. Also, Patent Document 2 discloses a tempered glass article in which a protective layer is provided on the edge surface of a tempered glass substrate whose outer periphery is chamfered.

[0003] International Publication No. WO 2017 / 038853 International Publication No. WO 2013 / 154034

[0004] However, when the tempered glass articles described in Patent Documents 1 and 2 are used as cover glass, if an object collides with the edge of the tempered glass article, the impacted portion may be chipped.

[0005] An object of the present invention is to provide a tempered glass article having increased edge strength.

[0006] A tempered glass article according to one aspect of the present invention includes a chemically strengthened tempered glass substrate having a first main surface that is a viewing surface, a second main surface opposite the first main surface, and an end surface perpendicular to the first main surface and the second main surface, and a protective layer provided on the end surface, wherein the protective layer, in a cross-sectional view perpendicular to the first main surface, has a base portion extending along the end surface from a first end portion on the first main surface side of the end surface to a second end portion on the second main surface side, and an arc portion connecting the first end portion and the second end portion, and satisfies the following formulas (1), (2), and (3): C1 / C2≧1.1 (1) C1: potassium concentration at the first end or the second end at the end face C2: potassium concentration at the center in the thickness direction of the strengthened glass substrate at the end face 0.18≦H / L≦1.21 (2) H: length from the apex of the arc portion to the end face L: length of the base 40°≦θ1≦135° (3) θ1: first contact angle on the first end side of the arc portion

[0007] According to the present invention, a tempered glass article having increased edge strength can be provided.

[0008] FIG. 1 is a plan view of a tempered glass article according to first to fourth embodiments. FIG. 2 is a cross-sectional view of the tempered glass article according to the first embodiment taken along line A-A in FIG. 1. FIG. 3 is an explanatory diagram of a manufacturing method of a tempered glass article according to first to fourth embodiments. FIG. 4 is a cross-sectional view of a tempered glass article according to a second embodiment taken along line A-A in FIG. 1. FIG. 5 is a cross-sectional view of a tempered glass article according to a third embodiment taken along line A-A in FIG. 1. FIG. 6 is a cross-sectional view of a tempered glass article according to a fourth embodiment taken along line A-A in FIG. 1. FIG. 7 is a schematic side view of an impact tester used in the examples. FIG. 8 is a schematic plan view of an impact tester used in the examples. FIG. 9 is a schematic side view of a sharpness evaluation tester. FIG. 10 is a schematic front view of a sharpness evaluation tester. FIG. 11 is a schematic view showing the positional relationship between a light source and a detector in an appearance evaluation test.

[0009] First Embodiment A first embodiment of the present invention will now be described. Note that in order to facilitate understanding of the present invention, the various components may be exaggerated in the drawings described below.

[0010] <Configuration of the tempered glass article> First, the configuration of the tempered glass article will be described. Fig. 1 is a plan view of the tempered glass article. Fig. 2 is a cross-sectional view of the tempered glass article taken along line AA in Fig. 1.

[0011] The tempered glass article 1A shown in Fig. 1 includes a tempered glass substrate 2, and a low-reflection film 3 and a protective layer 4A provided on the tempered glass substrate 2. Applications of the tempered glass article 1A are not particularly limited, and examples thereof include a cover glass for an in-vehicle or portable display and a combiner for projecting an image in a head-up display. In this embodiment, as shown in Fig. 2 , a configuration is exemplified in which the tempered glass article 1A is used as a cover glass provided on the display surface 91 side of a display 9.

[0012] The strengthened glass substrate 2 is formed, for example, in the shape of a rectangular plate, and has a first main surface 21, a second main surface 22 opposite the first main surface 21, and an end surface 23 perpendicular to the first main surface 21 and the second main surface 22. Here, "the end surface 23 being perpendicular to the first main surface 21 and the second main surface 22" means that the ridge portion at the boundary between the end surface 23 and the first main surface 21 and the ridge portion at the boundary between the end surface 23 and the second main surface 22 are not chamfered, and does not only mean the case where the angle between the end surface 23 and the first main surface 21 or the second main surface 22 is 90°, but also includes the case where the angle is within 90°±5°. In the strengthened glass article 1A including the strengthened glass substrate 2, the second main surface 22 is bonded to the display surface 91. When tempered glass article 1A is used in this manner, first main surface 21 serves as a viewing surface that is viewed by a user. Furthermore, if a housing of display 9 or the like is not present in a position facing end surface 23, protective layer 4A is entirely exposed.

[0013] The glass composition of the tempered glass substrate 2 is not particularly limited as long as it is a composition that can be chemically strengthened. The tempered glass substrate 2 may be, for example, soda-lime glass, aluminosilicate glass, or alkali aluminosilicate glass. The thickness of the tempered glass substrate 2 is not particularly limited, but is typically preferably 5 mm or less, more preferably 3 mm or less, to ensure effective chemical strengthening. Furthermore, when used as a cover glass for an in-vehicle display such as a car navigation system, the thickness of the tempered glass substrate 2 is preferably 0.2 mm or more, more preferably 0.8 mm or more, and even more preferably 1 mm or more, from the viewpoint of strength. The arithmetic mean roughness Ra of the end surface 23 is preferably 0.1 μm or more, more preferably 0.3 μm or more. Furthermore, the arithmetic mean roughness Ra of the end surface 23 is preferably 2.0 μm or less, more preferably 1.0 μm or less. In this embodiment, the upper and lower limits can be appropriately combined.

[0014] The strengthened glass substrate 2 is manufactured by a chemical strengthening process using potassium nitrate molten salt. Potassium ions are introduced into the entire end surface 23 of the strengthened glass substrate 2 through the chemical strengthening process. The end surface 23 is configured to satisfy the following formula (1): C1 / C2≧1.1 (1) where C1 is the potassium concentration at the first end 231 on the first main surface 21 side of the end surface 23 or the second end 232 on the second main surface 22 side of the end surface 23. C2 is the potassium concentration at the thickness direction center 233 of the strengthened glass substrate 2 on the end surface 23. Formula (1) is satisfied at all positions around the periphery of the strengthened glass substrate 2 on the end surface 23. The potassium concentrations represented by C1 and C2 in formula (1) do not include the potassium concentration in the bulk portion of the strengthened glass substrate 2 other than the end surface 23, i.e., the bulk concentration outside the end surface 23. The bulk concentration is approximately the same as the arithmetic average potassium ion concentration relative to the volume of the strengthened glass substrate 2 before chemical strengthening. The potassium concentration can be calculated, for example, by the method described in Patent Document 1. First, line analysis is performed on the end surface 23 using EDX (energy dispersive X-ray spectrometry). The potassium ion concentration (atomic ratio) normalized by silicon ions is then calculated as the potassium concentration represented by C1 and C2. Because ion exchange is more likely to occur at the first end 231 or the second end 232 of the end surface 23 than at the thickness direction center 233, C1 / C2 in the above formula (1) is 1.1 or greater, preferably 1.2 or greater, more preferably 1.3 or greater, and even more preferably 1.4 or greater. In this embodiment, the upper and lower limits of C1 / C2 in the above formula (1) can be appropriately combined. The potassium concentration C1 is preferably 0.25 or greater, more preferably 0.27 or greater, and even more preferably 0.29 or greater. The potassium concentration C1 is preferably 0.40 or less, more preferably 0.35 or less, and even more preferably 0.32 or less. The potassium concentration C2 is preferably 0.15 or more, more preferably 0.17 or more, and even more preferably 0.19 or more. The potassium concentration C2 is preferably 0.25 or less, more preferably 0.23 or less, and even more preferably 0.21 or less.In this embodiment, the upper and lower limits of the potassium concentrations C1 and C2 can be combined as appropriate.

[0015] In the first embodiment and the second to fourth embodiments described later, the strengthened glass substrate 2 is a flat plate. However, the strengthened glass substrate 2 may have a curved portion that is curved so that the strengthened glass substrate 2 is concave or convex when attached to the display surface 91 side of the display 9. The radius of curvature of the curved portion is preferably 50 mm or more, more preferably 100 mm or more, and even more preferably 200 mm or more. The radius of curvature of the curved portion is, for example, 10,000 mm or less, preferably 5,000 mm or less, and more preferably 3,000 mm or less. In this embodiment, the upper and lower limits of the radius of curvature of the curved portion can be appropriately combined. In this application, "curved" refers to a radius of curvature of 10,000 mm or less, and a radius of curvature greater than 10,000 mm is considered to be a flat plate. The shape of the curved portion of the strengthened glass substrate 2 may be a curved shape curved in only a single direction, a curved shape curved in two orthogonal directions, or a curved shape curved in three or more directions. In the first to fourth embodiments, the strengthened glass substrate 2 has an end face 23 that is perpendicular to the first main surface 21 and the second main surface 22. However, when the strengthened glass substrate 2 has a curved portion near the end face 23, this means that the tangent to the first main surface 21 at the first end 231 is perpendicular to the end face 23.

[0016] The low-reflection film 3 is provided on the first main surface 21, which is the viewing surface. In the first to fourth embodiments, the low-reflection film 3 is provided on the first main surface 21 except for the outer periphery, but it may be provided on the entire surface. The configuration of the low-reflection film 3 is not particularly limited as long as it is capable of suppressing light reflection. For example, it may be configured by stacking a high-refractive index layer having a refractive index of 1.9 or more at a wavelength of 550 nm and a low-refractive index layer having a refractive index of 1.6 or less at a wavelength of 550 nm. It may also be configured with only one low-refractive index layer. The low-reflection film 3 may be configured to include one high-refractive index layer and one low-refractive index layer, or may be configured to include two or more of each. When two or more high-refractive index layers and two or more low-refractive index layers are included, it is preferable that the high-refractive index layers and the low-refractive index layers are alternately stacked. The low-reflection film 3 may not be provided. In addition, at least one layer selected from an anti-reflection layer, an anti-glare layer, and an anti-fouling layer may be provided on the first main surface 21, and at least one layer selected from a decorative layer and a light-blocking layer may be provided on the second main surface 22.

[0017] The protective layer 4A is formed by curing a UV-curable resin. The protective layer 4A may be formed from a photocurable resin that cures with light of a wavelength other than UV, or a thermosetting resin. The protective layer 4A may be a cured product of one or more curable resin compositions selected from, for example, ene-thiol resins, silicone resins, epoxy resins, polyester resins, acrylic resins, and urethane resins. The curable resin composition may be a two-component curable resin composition comprising a curing agent and a curing agent. The use of a two-component curable resin composition allows curing at room temperature without UV irradiation or heating. Examples of two-component curable resin compositions include curable resin compositions of epoxy resins, polyester resins, polyurethane resins, and silicone resins. In terms of the appearance of the tempered glass article 1A, it is preferable to design the refractive index of the protective layer 4A so that the difference between the refractive index of the tempered glass substrate 2 is 0.2 or less. As shown in FIG. 1 , the protective layer 4A is provided so as to entirely cover each end face 23 corresponding to the four sides of the tempered glass substrate 2 in a plan view, but may be provided so as to cover only a portion of the edge face 23 in the circumferential direction. For example, when the tempered glass article 1A is attached to a display 9, the protective layer 4A may be provided on the end faces 23 facing upward and both left and right, and the protective layer 4A may not be provided on the end face 23 facing downward. As shown in FIG. 2 , in a cross-sectional view perpendicular to the first main surface 21, the protective layer 4A has a base portion 41A extending along the end face 23 from a first end 231 to a second end 232 of the end face 23, and an arc portion 42A connecting the first end 231 and the second end 232. The protective layer 4A is composed of the base portion 41A and the arc portion 42A described above and is provided so as not to be present on the first main surface 21 or the second main surface 22.

[0018] The protective layer 4A is formed into a shape that satisfies the following formula (2): 0.18≦H / L≦1.21 (2) H: length from the vertex 421A of the arc portion 42A to the end face 23 (bottom portion 41A) L: length of the bottom portion 41A The vertex 421A is the position of the arc portion 42A that is farthest from the bottom portion 41A in the plane direction of the first main surface 21. The length from the vertex 421A to the end face 23 is the shortest length along the plane direction of the first main surface 21. Note that H in the above formula (2) is sometimes referred to as the "maximum height of the protective layer." H / L in formula (2) is 0.18 or more, preferably 0.22 or more, more preferably 0.26 or more, and even more preferably 0.30 or more. Furthermore, H / L in formula (2) is 1.21 or less, preferably 1.00 or less, more preferably 0.80 or less, and even more preferably 0.60 or less. In this embodiment, the upper and lower limits of H / L in formula (2) can be appropriately combined. Furthermore, the maximum height H of the protective layer is preferably 50 μm or more, more preferably 60 μm or more, and most preferably 72 μm or more. Furthermore, the maximum height H of the protective layer is preferably 1500 μm or less, more preferably 1000 μm or less, and most preferably 600 μm or less. In this embodiment, the upper and lower limits of the maximum height H of the protective layer can be appropriately combined. Furthermore, in order to further increase the strength of the end portion of the tempered glass article 1A, the length L of the base portion 41A is preferably 500 μm or more, more preferably 700 μm or more, and most preferably 1100 μm or more. Furthermore, from the viewpoint of reducing the weight when an in-vehicle display such as a car navigation system is mounted on a vehicle, the length L of the base 41A is preferably 3000 μm or less, more preferably 2000 μm or less, and most preferably 1300 μm or less. In this embodiment, the upper and lower limits of the length L of the base 41A can be combined as appropriate.

[0019] The protective layer 4A is formed so that the vertex 421A is located on a virtual center line C that passes through the thickness direction center 233 of the end face 23 and is parallel to the first main surface 21, i.e., is located at the center of the tempered glass substrate 2 in the thickness direction. Hereinafter, the thickness direction center of the tempered glass substrate 2 may be referred to as the "center in the substrate thickness direction." Furthermore, the direction in which the virtual center line C extends may be referred to as the "height direction of the protective layer." Note that "the vertex 421A is located at the center in the substrate thickness direction" means both a case in which the vertex 421A is located exactly at the center in the substrate thickness direction and a case in which the vertex 421A is located 1 μm or less away from the center in the substrate thickness direction toward the first main surface 21 or the second main surface 22.

[0020] The protective layer 4A is formed into a shape that satisfies the following formula (3): 40°≦θ1≦135° (3) θ1: First contact angle of the arc portion 42A on the first end 231 side. The first contact angle θ1 and the second contact angle θ2 on the second end 232 side of the arc portion 42A are angles calculated using the θ / 2 method. The first contact angle θ1 is calculated based on the assumption that the arc from the first end 231 to the vertex 421A is part of a circle. The second contact angle θ2 is calculated based on the assumption that the arc from the second end 232 to the vertex 421A is part of a circle. In the first embodiment, the vertex 421A is located at the center of the substrate thickness direction, so the first contact angle θ1 and the second contact angle θ2 are the same. The first contact angle θ1 is 40° or greater in order to reduce the sharpness of the first end 231. The first contact angle θ1 is preferably 45° or more, more preferably 65° or more, and most preferably 75° or more. From the viewpoint of improving the appearance of the strengthened glass article 1A, the first contact angle θ1 is 135° or less, preferably 90° or less, more preferably 77° or less, and most preferably 75° or less. In this embodiment, the upper and lower limits of the first contact angle θ1 can be appropriately combined.

[0021] At least one bubble B is present inside the protective layer 4A, but no bubbles are required. The shape of the bubble B is often close to an ellipsoid. The size of the bubble B is preferably such that the length of the largest diameter is 10 μm or more and 8000 μm or less.

[0022] The protective layer 4A is preferably configured to satisfy the following condition: 0≦L ＊ ≦95 (CIE1976L ＊ a ＊ b ＊ chromaticity coordinate) L ＊ L refers to the brightness of reflected light in the CIE-Lab color system when standard illuminant D65 is used as the illumination light. ＊ is calculated based on JIS Z 8781-4 using the spectral reflectance measured based on JIS R3106. ＊ is the L measured based on light reflected from the outer periphery of a tempered glass article including a protective layer, according to the method described in the Examples. ＊ The above L of the protective layer 4A ＊ is preferably 0 or more, more preferably 5 or more, and even more preferably 10 or more, and is preferably 95 or less, more preferably 80 or less, and even more preferably 50 or less, and most preferably 25 or less. ＊ When the thickness is within the above range, the appearance of the tempered glass article 1A is improved.

[0023] <Method of manufacturing a strengthened glass article> Next, a method of manufacturing the strengthened glass article 1A will be described. Fig. 3 is an explanatory diagram of a method of manufacturing a strengthened glass article.

[0024] As shown in FIG. 3 , the method for manufacturing the strengthened glass article 1A of the first embodiment includes a raw plate preparation step, a laser irradiation step, a chemical strengthening step, a low-reflection film formation step, a separation step, and a protective layer formation step.

[0025] In the raw substrate preparation step, a raw substrate 10 having a size from which at least one strengthened glass substrate 2 can be obtained is prepared.

[0026] In the laser irradiation process, a plurality of void regions 11 are formed by irradiating one of the main surfaces of the raw sheet 10 with laser light from a direction perpendicular to the one main surface. The one main surface irradiated with the laser light may be the main surface corresponding to the first main surface 21 or the second main surface 22 of the strengthened glass substrate 2. The void region 11 includes an in-plane void region and an internal void row. The in-plane void region is formed on the one main surface of the raw sheet 10 irradiated with the laser light. The in-plane void region is a linear region formed by a plurality of voids aligned in one direction at a predetermined interval. The internal void row is formed on the other main surface side of the in-plane void region. The internal void row is a linear region formed by a plurality of voids aligned in the thickness direction of the raw sheet 10 at a predetermined interval on the other main surface side of each void constituting the in-plane void region. FIG. 3 shows a case where three void regions 11 extending in the longitudinal direction of a rectangular raw plate 10 and four void regions 11 extending in the lateral direction are formed.

[0027] In the chemical strengthening process, the base plate 10 having the void region 11 formed therein is chemically strengthened using potassium nitrate molten salt. The chemical strengthening process is performed under conditions where the edge surface 23 of the strengthened glass substrate 2 obtained from the base plate 10 satisfies the above formula (1). The reason why potassium ions are introduced into the edge surface 23, which is not exposed in the state of the base plate 10, is presumably because the molten salt is introduced into the interior of the base plate 10 through each void that constitutes the void region 11, and a substitution reaction occurs between the introduced molten salt and the portion corresponding to the edge surface 23.

[0028] In the low-reflection film forming step, the low-reflection film 3 is formed on the main surface of the raw plate 10 corresponding to the first main surface 21 of the strengthened glass substrate 2 by a known method.

[0029] In the separation process, the base plate 10 is divided along the void regions 11 to separate the tempered glass substrates 2. In the separation process, the voids constituting the void regions 11 function like perforations formed on the main surface and inside of the base plate 10, thereby facilitating separation of the tempered glass substrates 2. The method for separating the tempered glass substrates 2 is not particularly limited, but the method shown in FIG. 9 or 10 of Patent Document 1 may be used. FIG. 3 shows a case where six tempered glass substrates 2 can be separated from the base plate 10. As described above, the arithmetic mean roughness Ra of the end surface 23 of the tempered glass substrate 2 obtained in this manner is 0.1 μm or more and 2.0 μm or less.

[0030] In the protective layer forming step, a protective layer 4A is formed on the end surface 23 of the strengthened glass substrate 2. The method for forming the protective layer 4A on the end surface 23 is not particularly limited, but may include the following method including an ultraviolet curable resin preparing step, a coating preparation step, a coating step, a curing preparation step, and a curing step.

[0031] In the UV-curable resin preparation step, for example, the UV-curable resin is stirred to incorporate air bubbles into the UV-curable resin. In the coating preparation step, the tempered glass substrate 2 is fixed so that one end face 23 faces upward, for example, so that the end face 23 is perpendicular to the vertical direction. Note that the coating preparation step may be performed before, after, or simultaneously with the UV-curable resin preparation step. In the coating step, after the coating preparation step, the UV-curable resin is applied to the entire end face 23 while moving a coating nozzle above the upward-facing end face 23. At this time, the UV-curable resin is applied so as not to adhere to the first main surface 21 and the second main surface 22. Furthermore, the above-described coating preparation step and coating step are performed on the remaining three end faces 23, and the UV-curable resin is applied with the end faces 23 to be coated facing upward. In addition, the ultraviolet curable resin may not contain bubbles in the ultraviolet curable resin preparation step, and the ultraviolet curable resin containing bubbles may be applied by adjusting the application state in the application step. Furthermore, the application step only needs to be performed on the portion where the protective layer 4A needs to be provided. For example, the application step may be performed on the entire one to three end faces 23, or may be performed on only a portion of one end face 23 in the outer circumferential direction.

[0032] In the curing preparation step, after the application of the ultraviolet-curable resin to all of the end faces 23 that require application is completed, the strengthened glass substrate 2 is rotated so that the end faces 23 are parallel to the vertical direction, that is, so that the first main surface 21 or the second main surface 22 faces upward and the end faces 23 face sideways. In the curing step, after the curing preparation step is performed, ultraviolet rays are irradiated onto the ultraviolet-curable resin to form the protective layer 4A having the above-mentioned properties.

[0033] In the above-described method for forming the protective layer 4A, in the coating process, the UV-curable resin is applied in a manner that, due to surface tension, the UV-curable resin has an arc-shaped portion connecting the first end 231 and the second end 232, with the apex of the arc-shaped portion positioned at the center of the substrate thickness direction. Then, in the pre-curing process, the end surface 23 to which the UV-curable resin is applied faces sideways. When the end surface 23 faces sideways, the uncured UV-curable resin may deform due to gravity, causing the apex of the arc-shaped portion to shift downward from the center of the substrate thickness direction. In the first embodiment, at least one of the viscosity of the UV-curable resin and the time from the pre-curing process to the curing process is adjusted to prevent the UV-curable resin from deforming due to gravity when the end surface 23 to which the UV-curable resin is applied faces sideways. By the above-described method for forming the protective layer 4A, a protective layer 4A is formed in which the apex 421A is positioned at the center of the substrate thickness direction and which contains bubbles B therein. The protective layer formation process may also be performed to form a protective layer 4A that does not contain bubbles B therein.

[0034] Effect of First Embodiment The tempered glass article 1A includes a chemically strengthened tempered glass substrate 2 having a first main surface 21 and a second main surface 22 that are viewing surfaces, and an end surface 23 perpendicular to the first main surface 21 and the second main surface 22. The tempered glass article 1A includes a protective layer 4A provided on the end surface 23. The protective layer 4A has a base portion 41A and an arc portion 42A. The potassium concentration at the end surface 23 satisfies the above formula (1). The protective layer 4A satisfies the above formulas (2) and (3). By providing the protective layer 4A having such a configuration on the end surface 23, as shown in FIG. 2 , when the tempered glass article 1A is attached to the display 9 and an object P approaches the first end 231, the object P collides with the protective layer 4A before colliding with the first end 231. This collision between the protective layer 4A and the object P reduces the impact on the first end 231. Furthermore, because the distribution of the potassium concentration on end face 23 satisfies formula (1) above, the strength of the portions on the first and second end faces 231, 232 sides is increased compared to when formula (1) above is not satisfied, that is, when the potassium concentration on end face 23 is constant in the thickness direction of strengthened glass substrate 2. Therefore, even in the case of strengthened glass article 1A in which the ridge portions at the boundaries between end face 23 and first and second main surfaces 21, 22 are not chamfered and these ridge portions have a shape that makes them prone to chipping, the strength of the end portions can be increased.

[0035] Furthermore, when the protective layer 4A having the above configuration is provided on the edge surface 23, when a person's finger Q (not shown) approaches the edge surface 23, the person's finger Q does not come into contact with the edge surface 23 but comes into contact with the protective layer 4A. If the ridge portions at the boundaries between the first main surface 21, the second main surface 22, and the edge surface 23 of the tempered glass article 1A are sharp, there is a risk that the person's finger Q will come into contact with the edge surface 23 of the tempered glass article 1A and be injured when the person carries the tempered glass article 1A. However, by providing the protective layer 4A having the above configuration on the edge surface 23, the sharpness of the ridge portions at the boundaries between the first main surface 21, the second main surface 22, and the edge surface 23 of the tempered glass article 1A can be reduced, thereby preventing injury to the person's finger Q.

[0036] 2 , when tempered glass article 1A is used so that the outer periphery of first main surface 21 is not hidden by the housing of display 9 or the like and the entire first main surface 21 is visible, the appearance of tempered glass article 1A is impaired if an extended portion in which part of the protective layer extends onto the outer periphery of first main surface 21 is present, as described in Patent Document 2. Protective layer 4A of tempered glass article 1A is provided so as not to be present on first main surface 21 or second main surface 22, and this can prevent the appearance of tempered glass article 1A from being impaired.

[0037] Protective layer 4A contains bubbles B. Therefore, when protective layer 4A is formed using the same amount of ultraviolet-curable resin, the volume of protective layer 4A can be increased compared to a case where protective layer 4A does not contain bubbles B, and the impact absorption capacity of protective layer 4A can be increased. Therefore, the strength of the edge of tempered glass article 1A can be further increased.

[0038] [Second embodiment] Next, a second embodiment of the present invention will be described. Figure 4 is a cross-sectional view of the strengthened glass article taken along line A-A in Figure 1. Note that the same components as those in the first embodiment are given the same names and symbols, and descriptions thereof will be simplified or omitted.

[0039] 1 and 4 includes a tempered glass substrate 2, a low-reflection film 3, and a protective layer 4B. The configuration of the protective layer 4B is the same as that of the protective layer 4A except for the shape. The shape of the protective layer 4B will be described below.

[0040] The protective layer 4B has a base portion 41B extending along the end surface 23 from the first end 231 to the second end 232 on the end surface 23, and an arc portion 42B connecting the first end 231 and the second end 232. The protective layer 4B is provided so as not to be present on the first main surface 21 or the second main surface 22. The protective layer 4B is formed into a shape that satisfies the above formulas (2) and (3). The protective layer 4B is formed so that the apex 421B is located closer to the second main surface 22 than the center in the substrate thickness direction. Therefore, the first contact angle θ1 is smaller than the second contact angle θ2. At least one bubble B may be present inside the protective layer 4B, or no bubbles may be present.

[0041] The protective layer 4B is preferably configured to satisfy the following condition: 0≦L ＊ ≦95 (CIE1976L ＊ a ＊ b ＊ chromaticity coordinates) L of protective layer 4B ＊ is preferably 0 or more, more preferably 5 or more, and even more preferably 10 or more, and is preferably 95 or less, more preferably 80 or less, even more preferably 50 or less, and most preferably 25 or less. ＊ When the thickness is within the above range, the appearance of the tempered glass article 1B is improved.

[0042] <Method for manufacturing tempered glass article> Next, a method for manufacturing tempered glass article 1B will be described with reference to Fig. 3. As shown in Fig. 3, the method for manufacturing tempered glass article 1B of the second embodiment includes the same steps as the method for manufacturing tempered glass article 1A of the first embodiment. The steps other than the protective layer forming step are the same as those of the first embodiment. The protective layer forming step will be described in detail below.

[0043] In the protective layer forming step, the method for forming the protective layer 4B on the end surface 23 is not particularly limited, but a method including the same steps as in the first embodiment may be used. In the method for forming the protective layer 4B, similar to the first embodiment, an ultraviolet-curable resin preparing step, an application preparing step, and an application step are performed, so that the ultraviolet-curable resin is applied with the apex of the arc portion positioned at the center in the substrate thickness direction. In the curing preparing step, the strengthened glass substrate 2 is rotated so that the first main surface 21 faces upward and the end surface 23 faces sideways. In the curing step, after the curing preparing step, ultraviolet light is irradiated onto the ultraviolet-curable resin to form the protective layer 4B containing bubbles B therein. Note that the protective layer forming step may be performed so as to form the protective layer 4B without bubbles B therein.

[0044] In the second embodiment, at least one of the viscosity of the UV-curable resin and the time from the pre-curing step to the curing step is adjusted so that the uncured UV-curable resin deforms due to gravity, displacing the apex of the arc portion below the center of the substrate thickness direction. Because the uncured UV-curable resin deforms with the first main surface 21 facing upward, a protective layer 4B is formed in which the apex 421B is located closer to the second main surface 22 than the center of the substrate thickness direction. To displace the apex of the arc portion below the center of the substrate thickness direction, air force may be applied to the uncured UV-curable resin, or the viscosity of the UV-curable resin may be reduced by heating it. Furthermore, the tempered glass substrate 2 may be moved upward, and the resulting inertial force may displace the apex of the arc portion below the center of the substrate thickness direction.

[0045] Advantages of the Second Embodiment According to the second embodiment, by providing the tempered glass article 1B with the protective layer 4B having the above-described configuration, the strength of the end portion of the tempered glass article 1B can be further increased, as in the first embodiment. Furthermore, as in the first embodiment, injury to a person's finger Q by the end surface 23 can be prevented.

[0046] As shown in FIG. 4 , when the tempered glass article 1B is attached to the display 9, the boundary line K of the range within which the user can view the tempered glass article 1B is a straight line including the user's eyes and the first end 231 of the tempered glass article 1B. As shown by the dashed-two-dot line, in the case of the protective layer 4A in which the vertex 421A is located at the center of the substrate thickness direction, when the user looks at the tempered glass article 1A, the portion of the protective layer 4A closer to the first main surface 21 than the center of the substrate thickness direction is located closer to the user than the boundary line K and is not hidden by the tempered glass substrate 2. This reduces the appearance of the tempered glass article 1A. On the other hand, in the case of the protective layer 4B in which the vertex 421B is located closer to the second main surface 22 than the center of the substrate thickness direction as shown by the solid line, when the user looks at the tempered glass article 1B, the portion of the protective layer 4B closer to the first main surface 21 than the center of the substrate thickness direction is located on the opposite side of the boundary line K from the user and is hidden by the tempered glass substrate 2. Furthermore, when the angle between boundary line K and first main surface 21 is equal to or smaller than a certain angle, a linear region of protective layer 4B along the outer edge of first main surface 21 appears black, making it difficult to identify protective layer 4B. This prevents deterioration in the appearance of tempered glass article 1B.

[0047] FIG. 4 illustrates a state in which the protective layer 4B, whose apex 421B is located closer to the second main surface 22 than the center in the substrate thickness direction, is completely hidden by the tempered glass substrate 2 when the user views the tempered glass article 1B. However, depending on the magnitude of the first contact angle θ1, the protective layer 4B may not be completely hidden by the tempered glass substrate 2. However, the size of this unhidden area is smaller than that of the protective layer 4A, and the appearance of the tempered glass article 1B is better than that of the tempered glass article 1A. In particular, when the apex 421B is located closer to the second main surface 22 than the center in the substrate thickness direction, the smaller the first contact angle θ1, the more easily the protective layer 4B is hidden by the tempered glass substrate 2, thereby suppressing a deterioration in the appearance of the tempered glass article 1B. From this perspective, the first contact angle θ1 of the protective layer 4B is preferably 77° or less, and more preferably 75° or less. Furthermore, the first contact angle θ1 of the protective layer 4B is preferably 40° or more, and more preferably 65° or more. In this embodiment, the upper limit and lower limit of the first contact angle θ1 can be combined as appropriate.

[0048] From the viewpoint that a smaller first contact angle θ1 can suppress deterioration in appearance, it is conceivable to reduce the first contact angle θ1 by positioning the apex of the protective layer at the center in the substrate thickness direction and reducing the maximum height H. However, in this case, the volume of the protective layer is reduced, which reduces the impact absorption capacity and the strength of the end of the tempered glass article. Therefore, it is not possible to simultaneously improve the strength of the end of the tempered glass article and suppress deterioration in appearance. On the other hand, as in the case of protective layer 4B, by increasing the maximum height H to a certain extent and positioning apex 421B closer to the second main surface 22 than the center in the substrate thickness direction, the first contact angle θ1 can be reduced, thereby suppressing a reduction in the volume of protective layer 4B and a reduction in impact absorption capacity. Therefore, it is possible to simultaneously improve the strength of the end of tempered glass article 1B and suppress deterioration in appearance.

[0049] [Third embodiment] Next, a third embodiment of the present invention will be described. Fig. 5 is a cross-sectional view of the strengthened glass article taken along line A-A in Fig. 1. Note that the same components as those in the second embodiment are given the same names and symbols, and descriptions thereof will be simplified or omitted.

[0050] 1 and 5 includes a tempered glass substrate 2, a low-reflection film 3, and a protective layer 4C. The configuration of the protective layer 4C is the same as that of the protective layer 4A except for the shape. The shape of the protective layer 4C will be described below.

[0051] The protective layer 4C has a base portion 41C extending along the end surface 23 from the first end 231 to the second end 232 on the end surface 23, and an arc portion 42C connecting the first end 231 and the second end 232. The protective layer 4C is provided so as not to be present on the first main surface 21 or the second main surface 22. The protective layer 4C is formed into a shape that satisfies the above formulas (2) and (3). The protective layer 4C is formed so that the apex 421C is located closer to the first main surface 21 than the center in the substrate thickness direction. Therefore, the first contact angle θ1 is larger than the second contact angle θ2. At least one bubble B may be present inside the protective layer 4C, or no bubbles may be present.

[0052] The protective layer 4C is preferably configured to satisfy the following condition: 0≦L ＊ ≦95 (CIE1976L ＊ a ＊ b ＊ chromaticity coordinates) L of protective layer 4C ＊ is preferably 0 or more, more preferably 5 or more, and even more preferably 10 or more, and is preferably 95 or less, more preferably 80 or less, and even more preferably 50 or less, and most preferably 25 or less. ＊ When is within the above range, the appearance of the tempered glass article 1C is improved.

[0053] <Method for manufacturing tempered glass article> Next, a method for manufacturing tempered glass article 1C will be described with reference to Fig. 3. As shown in Fig. 3, the method for manufacturing tempered glass article 1C of the third embodiment includes the same steps as the method for manufacturing tempered glass article 1A of the first embodiment. The steps other than the protective layer forming step are the same as those of the first embodiment. The protective layer forming step will be described in detail below.

[0054] In the protective layer forming step, the method for forming the protective layer 4C on the end surface 23 is not particularly limited, but a method including the same steps as in the first embodiment may be used. In the method for forming the protective layer 4C, similar to the first embodiment, an ultraviolet-curable resin preparing step, an application preparing step, and an application step are performed, so that the ultraviolet-curable resin is applied with the apex of the arc portion positioned on the virtual central line C. In the curing preparing step, the strengthened glass substrate 2 is rotated so that the second main surface 22 faces upward and the end surface 23 faces sideways. In the curing step, after the curing preparing step, ultraviolet light is irradiated onto the ultraviolet-curable resin to form the protective layer 4C containing bubbles B therein. Note that the protective layer forming step may be performed so as to form the protective layer 4C without bubbles B therein.

[0055] In the third embodiment, similarly to the second embodiment, at least one of the viscosity of the ultraviolet curable resin and the time from the pre-curing step to the curing step is adjusted so that the uncured ultraviolet curable resin deforms due to gravity. With the second main surface 22 facing upward, the uncured ultraviolet curable resin deforms, forming a protective layer 4C whose vertex 421C is located closer to the first main surface 21 than the center of the substrate in the thickness direction.

[0056] Advantages of the Third Embodiment According to the third embodiment, by providing the tempered glass article 1C with the protective layer 4C having the above-described configuration, the strength of the end portion of the tempered glass article 1C can be further increased, as in the first embodiment. Furthermore, as in the first embodiment, injury to a person's finger Q by the end surface 23 can be prevented.

[0057] As shown in Figure 5, when the tempered glass article 1C is attached to the display 9 and an object P approaches the first end 231, the object P collides with a portion of the protective layer 4C closer to the first main surface 21 than the center of the substrate in the thickness direction before colliding with the first end 231. Because the apex 421C is located closer to the first main surface 21 than the center of the substrate in the thickness direction, the portion of the protective layer 4C closer to the first main surface 21 is farther from the thickness direction center 233 than the same portion of the protective layer 4A, where the apex 421A indicated by the two-dot chain line is located at the center of the substrate in the thickness direction. Therefore, the position of the protective layer 4C that first collides with the object P is farther from the tempered glass substrate 2 than the position of the protective layer 4A that first collides with the object P. Therefore, the impact absorption capacity of the protective layer 4C is greater than that of the protective layer 4A, further increasing the strength of the end of the tempered glass article 1C.

[0058] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described. Fig. 6 is a cross-sectional view of the strengthened glass article taken along line A-A in Fig. 1. Note that the same components as those in the first embodiment are given the same names and symbols, and descriptions thereof will be simplified or omitted.

[0059] 1 and 6 includes a tempered glass substrate 2, a low-reflection film 3, and a protective layer 4D. The configuration of the protective layer 4D is the same as that of the protective layer 4A except for the shape, material, and physical properties. The shape, material, and physical properties of the protective layer 4D will be described below.

[0060] The protective layer 4D has a base portion 41D extending along the end surface 23 from the first end 231 to the second end 232 on the end surface 23, and an arc portion 42D connecting the first end 231 and the second end 232. The protective layer 4D is provided so as not to be present on the first main surface 21 or the second main surface 22. The protective layer 4D is formed into a shape that satisfies the above formulas (2) and (3). Note that, similar to the first embodiment, the protective layer 4D may be formed so that the vertex 421D is located at the center of the substrate thickness direction. Alternatively, similar to the second embodiment, the protective layer 4D may be formed so that the vertex 421D is located closer to the second main surface 22 than the center of the substrate thickness direction. Similarly to the third embodiment, the protective layer 4D may be formed so that the vertex 421D is located closer to the first main surface 21 than the center of the substrate thickness direction. At least one bubble B may be present inside the protective layer 4D, or no bubbles may be present.

[0061] The protective layer 4D is configured to satisfy the following condition: 0≦L ＊ ≦80 (CIE1976L ＊ a ＊ b ＊ chromaticity coordinates) L of protective layer 4D ＊ is 0 or more, preferably 5 or more, and more preferably 10 or more, from the viewpoint of imparting light-shielding properties to the end surface 23 of the tempered glass article 1D and improving the appearance of the tempered glass article 1D. ＊ is 80 or less, preferably 50 or less, more preferably 25 or less, and even more preferably 20 or less, from the viewpoint of imparting light-shielding properties to the end surface 23 of the tempered glass article 1D and improving the appearance of the tempered glass article 1D. ＊The upper and lower limit values ​​can be combined as appropriate. Furthermore, from the viewpoint of improving the appearance of the strengthened glass article 1D, the difference between the refractive index of the protective layer 4D and the refractive index of the strengthened glass substrate 2 is preferably 0.2 or less, more preferably 0.05 or less, and most preferably 0.02 or less. The difference between the refractive index of the protective layer 4D and the refractive index of the strengthened glass substrate 2 is preferably 0.001 or more, and more preferably 0 or more. In this embodiment, the upper and lower limit values ​​can be combined as appropriate.

[0062] The protective layer 4D preferably has a black, gold, silver, blue, or red pigment dispersed in a resin. ＊ ≦80, which can impart light-blocking properties to the end surface 23 of the tempered glass article 1D. As a result, the appearance of the tempered glass article 1D is improved. In particular, if a black pigment is dispersed in the resin, the boundary between the tempered glass substrate 2 and the protective layer 4D becomes difficult to distinguish, making the tempered glass substrate 2 and the protective layer 4D appear to be integrated, which is preferable from the viewpoint of improving the appearance of the tempered glass article 1D. As the pigment, for example, an organic pigment such as carbon black or an inorganic pigment such as titanium black is preferably used. In particular, an inorganic pigment is preferred because it can provide excellent durability, for example, even in an environment exposed to ultraviolet light.

[0063] <Method for manufacturing tempered glass article> Next, a method for manufacturing a tempered glass article 1D will be described with reference to Fig. 3. As shown in Fig. 3, the method for manufacturing the tempered glass article 1D of the fourth embodiment includes the same steps as the method for manufacturing the tempered glass article 1A of the first embodiment. The steps other than the protective layer forming step are the same as those of the first embodiment. The protective layer forming step will be described in detail below.

[0064] In the protective layer forming step, the method for forming the protective layer 4D on the end surface 23 is not particularly limited, but a method including the same steps as in the first embodiment may be used. In the method for forming the protective layer 4D, similar to the first embodiment, the UV-curable resin preparation step, the application preparation step, and the application step are performed, so that the UV-curable resin is applied with the apex of the arc portion positioned at the center of the substrate thickness direction. In the curing preparation step, the tempered glass substrate 2 is rotated so that the first main surface 21 or the second main surface 22 faces upward and the end surface 23 faces sideways. In the curing step, after the curing preparation step, UV light is irradiated onto the UV-curable resin to form the protective layer 4D containing bubbles B therein. Here, the protective layer 4D may be heated after irradiating the UV-curable resin with UV light. Heating the protective layer 4D improves adhesion between the glass and the resin and promotes curing of the UV-curable resin. The heating temperature is preferably 40°C or higher, more preferably 60°C or higher. The heating time is preferably 5 minutes or longer, more preferably 10 minutes or longer. The protective layer forming step may be performed so as to form a protective layer 4D that does not contain bubbles B. The strengthened glass article 1D may be manufactured by the same process as the manufacturing method for the strengthened glass article 1B of the second embodiment or the strengthened glass article 1C of the third embodiment.

[0065] Advantages of the Fourth Embodiment According to the fourth embodiment, by providing the tempered glass article 1D with the protective layer 4D having the above-described configuration, the strength of the end portion of the tempered glass article 1D can be further increased, as in the first embodiment. Furthermore, as in the first embodiment, injury to a person's finger Q by the end surface 23 can be prevented.

[0066] In addition, the L of the protective layer 4D ＊ is equal to or greater than 0 and equal to or less than 80, the protective layer 4D has light-blocking properties. Therefore, by providing the protective layer 4D having the above-described configuration on the strengthened glass article 1D, the appearance of the strengthened glass article 1D is improved.

[0067] As described above, this specification discloses the following configuration: [1] A tempered glass article comprising: a tempered glass substrate having a first main surface that is a viewing surface, a second main surface opposite the first main surface, and an end surface orthogonal to the first main surface and the second main surface, the tempered glass substrate having been subjected to a chemical strengthening treatment; and a protective layer provided on the end surface, wherein the protective layer has, in a cross-sectional view orthogonal to the first main surface, a base portion extending along the end surface from a first end portion on the first main surface side to a second end portion on the second main surface side, and an arc portion connecting the first end portion and the second end portion, and which satisfies the following formulas (1), (2), and (3): C1 / C2≧1.1 (1) C1: potassium concentration at the first end or the second end at the end face C2: potassium concentration at the end face in the thickness direction center of the strengthened glass substrate 0.18≦H / L≦1.21 (2) H: length from the apex of the arc portion to the end face L: length of the base 40°≦θ1≦135° (3) θ1: first contact angle on the first end side of the arc portion [2] The strengthened glass article according to [1], wherein the protective layer contains bubbles. [3] The strengthened glass article according to [1] or [2], wherein the apex of the arc portion is located closer to the second main surface than the center of the strengthened glass substrate in the thickness direction. [4] The strengthened glass article according to [3], wherein the first contact angle θ1 is 77° or less. [5] The tempered glass article according to [1] or [2], wherein the vertex of the arc portion is located closer to the first main surface than the center of the thickness direction of the tempered glass substrate. [6] The tempered glass article according to [1] or [2], wherein the lightness L ＊ A tempered glass article having a modulus of elasticity of 0 or greater and 80 or less.

[0068] Next, examples of the present invention will be described. Examples 1 and 2 and Examples 12 and 13 are comparative examples, and Examples 3 to 11 and Examples 14 to 22 are working examples. However, the present invention is not limited to these examples.

[0069] [Method for manufacturing tempered glass article and characteristics of protective layer] Example 1 A soda lime glass substrate having a thickness of 1.1 mm was prepared as a base plate. This base plate was subjected to the laser irradiation process shown in FIG. 2. In each in-plane void region, the center-to-center distance between adjacent voids was set to 5 μm. Next, a chemical tempering process was performed using potassium nitrate molten salt. Furthermore, the base plate subjected to the chemical tempering process was subjected to a separation process to obtain multiple tempered glass substrates. The tempered glass substrates were rectangular plates with long sides of 80 mm and short sides of 50 mm.

[0070] A protective layer forming step was performed on one end face of a tempered glass substrate under conditions in which the apex of the protective layer was positioned at the center of the substrate thickness direction, thereby obtaining a tempered glass article 1 of Example 1 having a protective layer. In the protective layer forming step, "PHOTOBOND 200" (hereinafter referred to as "transparent resin 1") manufactured by Sunrise Co., Ltd. was used as the ultraviolet curable resin. Note that no treatment was performed to incorporate air bubbles into the ultraviolet curable resin. The viscosity of the ultraviolet curable resin was 350 mPa s, the elastic modulus was 6 MPa, and the hardness (Shore D) was 55. The ultraviolet intensity in the curing step was 6000 mJ / cm ２ It was.

[0071] The characteristics of the protective layer were evaluated, including the first contact angle θ1, the maximum height H, the length L of the bottom edge portion in the thickness direction of the tempered glass substrate, and H / L. As shown in Table 1, the values ​​of θ1, H, L, and H / L were 15°, 72 μm, 1100 μm, and 0.07, respectively. The deviation E of the apex from the center of the substrate in the thickness direction was also evaluated. The value of E was 1 μm or less. In other words, the apex was located at the center of the substrate in the thickness direction. The potassium concentration of the tempered glass substrate was also evaluated using the method exemplified in the first embodiment. C1 / C2 was 1.2.

[0072] In the following Examples 2 to 22, the value of C1 / C2 is the same as that in Example 1.

[0073] <Example 2> A tempered glass article 1 of Example 2 was obtained by forming a protective layer on multiple tempered glass substrates manufactured under the same conditions as Example 1. The conditions for forming the protective layer were the same as those of Example 1, except that the amount of ultraviolet-curable resin used was greater than in Example 1, and the time from the curing preparation step to the curing step in the protective layer formation step was extended so that the apex of the protective layer was located closer to the second main surface than the center of the substrate thickness direction, i.e., on the side opposite the first main surface (the viewing surface). As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the characteristics of the protective layer, were 20°, 98 μm, 1100 μm, and 0.09, respectively. The apex was located closer to the second main surface than the center of the substrate thickness direction. The value of E was 3 μm.

[0074] <Example 3> A tempered glass article 1 of Example 3 was obtained by forming protective layers on multiple tempered glass substrates manufactured under the same conditions as in Example 1. The conditions for forming the protective layers were the same as those in Example 2, except that the amount of ultraviolet-curable resin used was greater than in Example 2. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 40°, 202 μm, 1100 μm, and 0.18, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 5 μm.

[0075] <Example 4> A tempered glass article 1 of Example 4 was obtained by forming protective layers on multiple tempered glass substrates manufactured under the same conditions as in Example 1. The conditions for forming the protective layers were the same as those in Example 3, except that the amount of ultraviolet-curable resin used was greater than in Example 3. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 62°, 333 μm, 1100 μm, and 0.30, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 5 μm.

[0076] <Example 5> A protective layer was formed on a plurality of tempered glass substrates manufactured under the same conditions as in Example 1, thereby obtaining the tempered glass article 1 of Example 5. The conditions for forming the protective layer were the same as those in Example 4, except that the amount of ultraviolet-curable resin used was greater than that in Example 4. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 75°, 450 μm, 1100 μm, and 0.41, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 37 μm.

[0077] <Example 6> A tempered glass article 1 of Example 6 was obtained by forming protective layers on multiple tempered glass substrates manufactured under the same conditions as in Example 1. The conditions for forming the protective layers were the same as those in Example 5, except that the amount of ultraviolet-curable resin used was greater than in Example 5. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 77°, 476 μm, 1100 μm, and 0.43, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 48 μm.

[0078] <Example 7> A protective layer was formed on a plurality of tempered glass substrates manufactured under the same conditions as in Example 1, thereby obtaining the tempered glass article 1 of Example 7. The conditions for forming the protective layer were the same as those in Example 6, except that the apex of the protective layer was positioned closer to the first main surface than the center in the substrate thickness direction. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 83°, 446 μm, 1100 μm, and 0.41, respectively. The apex was also positioned closer to the first main surface than the center in the substrate thickness direction. The value of E was 46 μm.

[0079] <Example 8> Protective layers were formed on multiple tempered glass substrates manufactured under the same conditions as in Example 1, thereby obtaining tempered glass article 1 of Example 8. The conditions for forming the protective layers were the same as those in Example 1, except that the amount of ultraviolet-curable resin used was greater than in Example 1. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 83°, 487 μm, 1100 μm, and 0.44, respectively. The value of E was 1 μm or less, and the apex was located at the center of the substrate in the thickness direction.

[0080] <Example 9> A tempered glass article 1 of Example 9 was obtained by forming protective layers on multiple tempered glass substrates manufactured under the same conditions as in Example 1. The conditions for forming the protective layers were the same as in Example 6, except that the amount of ultraviolet-curable resin used was greater than in Example 6. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 87°, 578 μm, 1100 μm, and 0.53, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 60 μm.

[0081] <Example 10> A protective layer was formed on a plurality of tempered glass substrates manufactured under the same conditions as in Example 1, thereby obtaining a tempered glass article 1 of Example 10. The conditions for forming the protective layer were the same as those in Example 9, except that the amount of ultraviolet curable resin used was greater than that in Example 9. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 110°, 943 μm, 1300 μm, and 0.73, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 10 μm.

[0082] <Example 11> Protective layers were formed on multiple tempered glass substrates manufactured under the same conditions as in Example 1, thereby obtaining tempered glass article 1 of Example 11. The conditions for forming the protective layers were the same as those in Example 8, except that the amount of ultraviolet-curable resin used was greater than that in Example 8. As shown in Table 1, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 135°, 1328 μm, 1100 μm, and 1.21, respectively. The value of E was 1 μm or less, and the apex was located at the center of the substrate in the thickness direction.

[0083] Example 12 A tempered glass article 1 of Example 12 was obtained under the same conditions as in Example 1, except that in the protective layer formation step, a black pigment-containing ultraviolet-curable resin (manufactured by Sekisui Material Solutions Co., Ltd., product name: PHOTOLEC-A-785-60BK-T-300, hereinafter referred to as "black resin 1") was used instead of transparent resin 1. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were each the same as in Example 1. Furthermore, the value of E was 1 μm or less, and the apex was located at the center of the substrate in the thickness direction.

[0084] <Example 13> Tempered glass article 1 of Example 13 was obtained under the same conditions as Example 2, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 20°, 98 μm, 1100 μm, and 0.09, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 3 μm.

[0085] Example 14 Tempered glass article 1 of Example 14 was obtained under the same conditions as Example 3, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 40°, 202 μm, 1100 μm, and 0.18, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 5 μm.

[0086] <Example 15> Tempered glass article 1 of Example 15 was obtained under the same conditions as Example 4, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 62°, 333 μm, 1100 μm, and 0.30, respectively. In addition, the apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 5 μm.

[0087] <Example 16> Tempered glass article 1 of Example 16 was obtained under the same conditions as Example 5, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 75°, 450 μm, 1100 μm, and 0.41, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 37 μm.

[0088] <Example 17> Tempered glass article 1 of Example 17 was obtained under the same conditions as Example 6, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 77°, 476 μm, 1100 μm, and 0.43, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 48 μm.

[0089] Example 18 Tempered glass article 1 of Example 18 was obtained under the same conditions as Example 7, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 83°, 446 μm, 1100 μm, and 0.41, respectively. The apex was located closer to the first main surface than the center in the substrate thickness direction. The value of E was 46 μm.

[0090] Example 19 Tempered glass article 1 of Example 19 was obtained under the same conditions as Example 8, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 83°, 487 μm, 1100 μm, and 0.44, respectively. The value of E was 1 μm or less, and the apex was located at the center of the substrate in the thickness direction.

[0091] <Example 20> Tempered glass article 1 of Example 20 was obtained under the same conditions as Example 9, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 87°, 578 μm, 1100 μm, and 0.53, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 60 μm.

[0092] Example 21 Tempered glass article 1 of Example 21 was obtained under the same conditions as Example 10, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 110°, 943 μm, 1300 μm, and 0.73, respectively. The apex was located closer to the second main surface than the center in the substrate thickness direction. The value of E was 10 μm.

[0093] Example 22 Tempered glass article 1 of Example 22 was obtained under the same conditions as Example 11, except that black resin 1 was used instead of transparent resin 1 in the protective layer formation step. As shown in Table 2, the values ​​of θ1, H, L, and H / L, which represent the properties of the protective layer, were 135°, 1328 μm, 1100 μm, and 1.21, respectively. The value of E was 1 μm or less, and the apex was located at the center of the substrate in the thickness direction.

[0094]

[0095]

[0096] The impact resistance and sharpness of the end face of the tempered glass article were evaluated by the following methods.

[0097] [Evaluation of Impact Resistance of Tempered Glass Article] <Configuration of Impact Tester> First, an impact tester 8 shown in Figures 7 and 8 was prepared. Note that in the following description, the direction of each component may be described based on the XYZ coordinate axes shown in Figures 7 and 8. The X-axis and Y-axis are axes that are perpendicular to each other and parallel to the horizontal plane. The Z-axis is an axis that is perpendicular to the X-axis and Y-axis and parallel to the vertical direction. Here, Figure 8 is a plan view of the impact tester of Figure 7 as viewed from the Z-axis direction. The impact tester 8 includes a base 81, a sample holder 82 that holds the tempered glass article 1 to be evaluated, and an impact applying unit 83 that applies an impact to the tempered glass article 1.

[0098] The base 81 is formed in the shape of a right-angled isosceles triangular prism with a base angle of 45° and is placed on a mounting table (not shown) so that the surface corresponding to one of the equal sides abuts against the mounting table (not shown). The sample holding unit 82 includes a holding member 821 made of a metal plate fixed to the surface corresponding to the base of the base 81, and a clamping unit (not shown). The strengthened glass article 1 is placed on the holding member 821 so that the first main surface 21 of the strengthened glass article 1 is inclined at 45° with respect to the horizontal plane. The sample holding unit 82 removably holds the strengthened glass article 1 placed on the holding member 821 by the clamping unit so that the inclined surface 821A facing diagonally downward of the holding member 821 and the end surface 23 are located on the same plane.

[0099] The impact applying unit 83 includes a bearing 831 through which a cylindrical shaft 84 extending in the X-axis direction is inserted, a rod 832 extending in a rod-like shape from the outer circumferential surface of the bearing, and an impactor 833 fixed to the tip of the rod 832. The impactor 833 includes a rectangular parallelepiped fixed body 834 and a triangular prism-shaped angled pin 835 fixed to one surface of the fixed body 834. The angled pin 835 was made of cemented carbide and had a tip 835A angled at 100°. The impactor 833 weighed 152.8 g. The impact applying unit 83 is configured so that the tip 835A of the angled pin 835 first comes into contact with the protective layer 4 of the tempered glass article 1 when the rod 832 becomes horizontal with respect to the Z-axis direction, as shown by the solid lines in Figures 7 and 8. Although the reference numeral 4 is omitted in FIG. 8, the tip 835 A of the impactor 833 is in contact with the protective layer 4 rather than the first end 231 .

[0100] <Evaluation of Impact Resistance> First, ten tempered glass articles 1 of Example 1 were prepared. Next, the rod 832 was rotated as shown by the two-dot chain lines in Figures 7 and 8 and stopped at a position where the impactor 833's impact energy was 0.5 mJ. One tempered glass article 1 was then held in the sample holder 82 so that the end surface 23 on which the protective layer 4 was provided was located flush with the inclined surface 821A. The force holding the impactor 833 at rest was then released, allowing the impactor 833 to freely rotate and collide with the tempered glass article 1 with a collision energy of 0.5 mJ. The impactor 833 was then moved in the X-axis direction to shift the collision position in the X-axis direction, and the impactor 833 was then collided with the tempered glass article 1 with a collision energy of 1.0 mJ. A similar test was performed on the remaining nine tempered glass articles 1, and the impactor 833 was collided with two collision positions aligned in the X-axis direction with collision energies of 0.5 mJ and 1.0 mJ. Ten tempered glass articles 1 for each of Examples 2 to 22 were prepared, and impactors 833 were collided with each tempered glass article 1 at two collision positions aligned in the X-axis direction with collision energies of 0.5 mJ and 1.0 mJ.

[0101] The impact positions of each of the 10 tempered glass articles 1 in Examples 1 to 22 were examined under a microscope to determine whether or not chipping of a predetermined size or larger occurred at each impact energy. In this determination, scratches with a length in the X-axis direction of 1.5 mm or more, a length in the Y-axis direction of 0.1 mm or more, or a length in the substrate thickness direction of 0.1 mm or more were determined to be chips. Next, for each of Examples 1 to 22, if the number of tempered glass articles 1 with chipping occurred at each impact energy was three or less, the glass was determined to meet the standard. If the number was four or more, the glass was determined to not meet the standard. That is, if the chipping incidence rate at each impact energy was 30% or less, the glass was determined to meet the standard. If the chipping incidence rate exceeded 30%, the glass was determined to not meet the standard. Furthermore, if the standard was not met at impact energies of 0.5 mJ or 1.0 mJ or more, the impact resistance was rated "C." If the standard was met when the impact energy was 0.5 mJ but not when it was 1.0 mJ, the impact resistance was rated as "B." If the standard was met when the impact energy was both 0.5 mJ and 1.0 mJ, the impact resistance was rated as "A."

[0102] <Impact Resistance Evaluation Results> The impact resistance evaluation results for Examples 1 to 11 are shown in Table 1. Examples 1 and 2, in which the protective layer 4 did not satisfy formulas (2) and (3), were evaluated as "C." On the other hand, Examples 3 to 11, in which the protective layer 4 satisfied formulas (2) and (3), were evaluated as either "B" or "A." The impact resistance evaluation results for Examples 12 to 22 are shown in Table 2. Examples 12 to 13, in which the protective layer 4 did not satisfy formulas (2) and (3), were evaluated as "C." On the other hand, Examples 14 to 22, in which the protective layer 4 satisfied formulas (2) and (3), were evaluated as either "B" or "A."

[0103] In Examples 1 to 2 and 12 to 13, the first contact angle θ1 was less than the lower limit of the condition for satisfying formula (3), and the portion of protective layer 4 on the first main surface 21 side was closer to thickness direction center 233 of end face 23 than the same portion in Examples 3 to 11 and 14 to 22 in which the first contact angle θ1 satisfied formula (3). Therefore, the position in protective layer 4 in Example 1 that was first struck by impactor 833 was closer to the tempered glass substrate than the corresponding position in protective layer 4 in Examples 3 to 11 and 14 to 22. As a result, the impact absorption capacity of protective layer 4 in Example 1 was smaller than that of protective layer 4 in Examples 3 to 11 and 14 to 22, which is thought to be why Examples 1 to 2 and 12 to 13 were evaluated as "C," while Examples 3 to 11 and 14 to 22 were evaluated as "B" or "A."

[0104] Furthermore, the evaluations of Examples 3 and 14, in which the first contact angle θ1 was 40°, and Examples 4 and 15, in which the first contact angle θ1 was 62°, were lower than those of Examples 5 to 11 and 16 to 22, in which the first contact angle θ1 was 75° or greater. For the same reasons as those described for Examples 1 and 2 and Examples 12 to 13, the portions of the protective layer 4 of Examples 3 to 4 and 14 to 15 on the first main surface 21 side are not sufficiently far from the thickness direction center 233 of the end face 23, as are the same portions of Examples 5 to 11 and 16 to 22. As a result, it is thought that the impact absorption capacity of the protective layer 4 of Examples 3 to 4 and 14 to 15 is not sufficiently large, and therefore Examples 3 to 4 and 14 to 15 were evaluated as "B," while Examples 5 to 11 and 16 to 22 were evaluated as "A."

[0105] From the above, it was confirmed that the strength of the end portion of the tempered glass article 1 can be increased by forming a protective layer 4 that satisfies formulas (2) and (3). In particular, it was confirmed that the strength of the end portion of the tempered glass article 1 can be further increased by forming a protective layer 4 that satisfies formulas (2) and (3) and has a first contact angle θ1 of 75° or more.

[0106] [Evaluation of Sharpness of Tempered Glass Article] <Configuration of Sharpness Evaluation Tester> First, a sharpness evaluation tester 90 shown in FIGS. 9 and 10 was prepared. In the following description, the direction of each component may be described based on the XYZ coordinate axes shown in FIGS. 9 and 10 . The X and Y axes are perpendicular to each other and parallel to the horizontal plane. The Z axis is perpendicular to the X and Y axes and parallel to the vertical direction. FIG. 10 is a front view of the sharpness evaluation tester of FIG. 9 as viewed from point D in FIG. 9 in the negative direction of the Y axis. The sharpness evaluation tester 90 includes a measurement base 92, a sharpness sample holder 93 that holds the tempered glass article 1 to be evaluated, and a sharpness evaluation unit 94 that applies an impact to the tempered glass article 1 by contact.

[0107] The measurement base 92 is formed in the shape of a right-angled isosceles triangular prism with a base angle of 45°, and a surface corresponding to one of the equal sides is placed on a mounting base (not shown). The sharpness sample holder 93 includes a base holding member 98 made of a metal plate fixed to the surface corresponding to the bottom side of the measurement base 92, a clamping portion (not shown), and a glass pedestal 99 located adjacent to the strengthened glass article 1 and the measurement base 92. As shown in Figure 9, the strengthened glass article 1 is placed on the base holding member 98 along one main surface of the glass pedestal 99 so that the first main surface 21 of the strengthened glass article 1 is inclined at 45° with respect to the horizontal plane. The sharpness sample holder 93 removably holds the strengthened glass article 1 placed on the base holding member 98 by the clamping portion.

[0108] The sharpness evaluation unit 94 includes a tester unit 96 extending in the Y-axis direction and a tape kit unit 97 fixed to the tip of the tester unit 96. The tape kit unit 97 includes three layers of tape 971 to 973 that simulate the softness of the fingerprint surface of an index finger. The layers are defined as a first layer 973, a second layer 972, and a third layer 971, starting from the outermost layer of the tape. A sharp edge tester (manufactured by Excel Corporation, product number: SET-50, hereinafter referred to as "SET-50") was used as the tester unit 96, and a tape kit TC-3 (hereinafter referred to as "TC-3") also manufactured by Excel Corporation was used as the tape kit unit 97. As shown in FIG. 10, TC-3 is a tape kit consisting of three layers of tape 971 to 973 that simulate the softness of the fingerprint surface of an index finger, stacked on a head 974 with a diameter of 12.7 mm, and SET-50 has the function of pressing TC-3 against the end face of the sample with a constant load.

[0109] <Evaluation of Sharpness> First, one tempered glass article 1 of Example 1 was prepared. Next, the tempered glass article 1 was fixed in a state inclined at 45 degrees relative to the horizontal plane. TC-3 attached to SET-50 was brought into contact with the protective layer 4 under a constant load (6.7 N in the direction of arrow F in FIG. 10 ). While maintaining the load, TC-3 was moved back and forth along the protective layer 4D for a distance of 100 mm (50 mm one way). The movement was performed for a total of 20 times over a period of 20 seconds. The state of TC-3 after the movement was confirmed, and if the tape of the first layer 973 of TC-3 was not cut, the sharpness was evaluated as "A." If the tape of the first layer 973 of the tape kit TC-3 was cut, the sharpness was evaluated as "B." One tempered glass article 1 each of Examples 2 to 22 was prepared, and the same evaluation as in Example 1 was performed.

[0110] <Sharpness Evaluation Results> The evaluation results of sharpness for Examples 1 to 11 are shown in Table 1. Example 1 was evaluated as "B". On the other hand, Examples 2 to 11 were evaluated as "A". The evaluation results of sharpness for Examples 12 to 22 are shown in Table 2. Example 12 was evaluated as "B". On the other hand, Examples 13 to 22 were evaluated as "A".

[0111] In Examples 1 and 12, the first contact angle θ1 is small, at 15°. The first end 231 in Examples 1 and 12 has a smaller first contact angle θ1 value and is sharper than the first end 231 in Examples 2 to 11 and Examples 13 to 22. As a result, it is believed that the sharpness evaluation of Examples 1 and 12 was "B," while the sharpness evaluation of Examples 2 to 11 and Examples 13 to 22 was "A."

[0112] From the above, it was confirmed that by forming a protective layer 4 that satisfies formula (3), the first contact angle θ1 can be made sufficiently large and the sharpness of the edge of the strengthened glass article 1 can be reduced.

[0113] [Evaluation of Appearance of Tempered Glass Article] <Method of Evaluating Appearance> Using the device shown in FIG. 11, the area of ​​the tempered glass article 1 on which the protective layer 4 was formed was evaluated for L of the CIE-Lab color system. ＊ The values ​​were determined and the appearance of the tempered glass article was evaluated. First, a light source 701 was installed above a workbench (not shown) so that the light irradiation direction was downward. A detector 702 was installed above the workbench so that the measurement range was located at the center of the irradiation range of the light source 701. As the light source 701, lighting sensitive to the visible light range was used. Specifically, a white LED lighting (OPF-S100X100W-DF, manufactured by Optex FA) was used. Note that, since the intensity of each wavelength in the visible range of a white LED is not constant, spectral data was obtained using a white calibration plate to create correction values, and by using the correction values, the L of the CIE-Lab color system was calculated. ＊The values ​​were calculated. A spectroradiometer (SR-5000 manufactured by Topcon Technohouse Corporation) was used as detector 702. Furthermore, a sheet member 703, "Multi-Paper Super White (A4 size, whiteness approximately 92%)," a copy paper manufactured by ASKUL Corporation, was placed in the measurement range on the workbench. Then, tempered glass article 1 was placed on sheet member 703 so that first main surface 21 faced upward and the center of the protective layer 4 in the circumferential direction (length direction) was located in the center of the imaging range of detector 702 when viewed from above. At this time, as shown in FIG. 11 , the angle θ3 between light 711 irradiated from light source 701 to protective layer 4 and light 712 reflected by protective layer 4 and detected by detector 702 was 45°. Furthermore, as shown in FIG. 11 , light source 701 was positioned so that the distance d1 between light source 701 and protective layer 4 was 90 mm. The detector 702 was positioned so that the distance d2 between the detector 702 and the protective layer 4 was 280 mm. For each tempered glass article 1, the protective layer 4 was irradiated with light 711 from the light source 701, while the detector 702 was used to detect and image light 712 reflected from the outer periphery of the tempered glass article 1 including the protective layer 4. Of the image data obtained by the detector 702, an arbitrary point in the outer periphery of the tempered glass article 1 including the protective layer 4, where the protective layer 4 was exposed, was designated as a measurement point P1, and the lightness L of the CIE-Lab color system was measured for a total of 9 pixels (348.9 μm square) in a 3×3 array around the measurement point P1. ＊ The average value is calculated as the brightness L ＊Ｐ１ Measurement points P2, P3, P4, and P5, which are different from the measurement point P1, were selected from the outer peripheral region of the strengthened glass article 1 including the protective layer 4, and the lightness L ＊Ｐ２ , P3 ＊Ｐ３ , P4 ＊Ｐ４ , P5 ＊Ｐ５ The lightness L ＊Ｐ１ ~Lightness L ＊Ｐ５ The median value of the protective layer 4 is taken. ＊ It was decided.

[0114] When a user visually checks the tempered glass article 1, depending on the shape of the protective layer 4, a linear region along the outer edge of the first main surface 21 of the protective layer 4 may appear black, making it difficult to identify the protective layer 4. ＊ It is believed that the smaller the value of L , the darker the protective layer 4 appears, making it more difficult to distinguish the boundary between the protective layer 4 and the tempered glass substrate 2, improving the appearance of the tempered glass article 1. From this perspective, the L of the protective layer 4 in each of the tempered glass articles 1 in Examples 1 to 22 was ＊ The above measurements were carried out for each tempered glass article 1, and L ＊ If the value was 25 or less, the appearance was rated as "A". ＊ If the value was greater than 25 and less than or equal to 80, the appearance was rated as "B". ＊ If the value was greater than 80, the appearance was rated as "C."

[0115] <Appearance Evaluation Results> The appearance evaluation results for Examples 1 to 11 are shown in Table 1. Examples 7 to 11 were rated "C." The protective layer 4 of Example 7 had its apex located closer to the first main surface 21 than the center of the substrate thickness direction, and the first contact angle θ1 was 83°. The protective layers 4 of Examples 8 and 11 had their apex located closer to the center of the substrate thickness direction, and the first contact angle θ1 was 83° or greater. The protective layers 4 of Examples 9 and 10 had their apex located closer to the second main surface 22 than the center of the substrate thickness direction, but the first contact angle θ1 was 87° or greater. Thus, the protective layers 4 of Examples 7 to 11 had a first contact angle θ1 of 83° or greater, and had a large area that reflected irradiated light toward the detector 702. This is thought to be why the protective layers 4 of Examples 7 to 11 had a larger width ratio of the area that appeared white and a smaller proportion of the black area. Hereinafter, the area in the protective layer 4 that reflects the irradiated light toward the detector 702 may be referred to as a "return reflection area."

[0116] The evaluations of Examples 2 to 6 were "A" or "B." The apex of the protective layer 4 in Examples 2 to 6 was located closer to the second main surface 22 than the center in the substrate thickness direction, and the first contact angle θ1 was 77° or less. Thus, the protective layer 4 in Examples 2 to 6 had a smaller first contact angle θ1 and a smaller back-reflection region than the protective layer 4 in Examples 7 to 11. Therefore, it is believed that the protective layer 4 in Examples 2 to 6 had a smaller width ratio of the region that appeared white and a larger proportion of black compared to the protective layer 4 in Examples 7 to 11. Furthermore, the evaluation of Example 6, in which the first contact angle θ1 was 77°, was lower than that of Examples 2 to 5, in which the first contact angle θ1 was 75° or less. Furthermore, when comparing Example 6 and Example 7, despite the fact that Example 6 had a larger maximum height H of the resin, Example 6 was evaluated as "B," which was higher than the evaluation of Example 7, "C." The reason for this is thought to be that in Example 6, the apex of the protective layer 4 is shifted toward the second main surface 22, and the first contact angle θ1 is smaller than in Example 7, in which the apex is shifted toward the first main surface 21.

[0117] The evaluation of Example 1 was "A." In protective layer 4 of Example 1, the apex was located at the center in the substrate thickness direction, but the first contact angle θ1 was 15° and the back-reflection region was small, which is thought to have reduced the proportion of the width of the region that appeared white and increased the proportion of black.

[0118] From the above, it was confirmed that in Examples 1 to 11, by forming a protective layer 4 with a small first contact angle θ1, deterioration in the appearance of the tempered glass article 1 can be suppressed. In such a protective layer 4, it was confirmed that, from the viewpoint of appearance, the first contact angle θ1 is preferably 77° or less, and more preferably 75° or less. Next, the evaluation results of the appearance of Examples 12 to 22 are shown in Table 2. All of Examples 12 to 22 were evaluated as "A." In Examples 12 to 22, by forming the protective layer 4 using the black resin 1, it was possible to suppress deterioration in the appearance of the tempered glass article 1. ＊ As a result of being able to achieve a value of ≦25, reflection of the irradiated light toward the detector 702 side is suppressed, and the strengthened glass article 1 and the protective layer 4 appear to be the same color, thereby improving the appearance.

[0119] Although the present invention has been described in detail 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. 2024-015431) filed on February 5, 2024, the contents of which are incorporated herein by reference.

[0120] 1, 1A, 1B, 1C, 1D... tempered glass article, 2... tempered glass substrate, 4, 4A, 4B, 4C, 4D... protective layer, 21... first main surface, 22... second main surface, 23... end surface, 41A, 41B, 41C, 41D... base portion, 42A, 42B, 42C, 42D... arc portion, 231... first end portion, 232... second end portion, 233... center portion in thickness direction, 421A, 421B, 421C, 421D... apex, B... air bubble, θ1... first contact angle.

Claims

1. A tempered glass substrate having a first main surface that is a viewing surface, a second main surface opposite the first main surface, and an end surface orthogonal to the first main surface and the second main surface, and having been subjected to a chemical strengthening treatment; and a protective layer provided on the end surface, wherein the protective layer has, in a cross-sectional view orthogonal to the first main surface, a base portion extending along the end surface from a first end on the first main surface side of the end surface to a second end on the second main surface side, and an arc portion connecting the first end and the second end, and the tempered glass article satisfies the following formulas (1), (2), and (3): C1 / C2≧1.1 (1) C1: potassium concentration at the first end or the second end at the end face C2: potassium concentration at the center in the thickness direction of the strengthened glass substrate at the end face 0.18≦H / L≦1.21 (2) H: length from the apex of the arc portion to the end face L: length of the base 40°≦θ1≦135° (3) θ1: first contact angle on the first end side of the arc portion 2. The tempered glass article according to claim 1, wherein the protective layer contains bubbles.

3. A tempered glass article according to claim 1, wherein the apex of the arc portion is located closer to the second main surface than the center of the tempered glass substrate in the thickness direction.

4. A tempered glass article according to claim 3, wherein the first contact angle θ1 is 77° or less.

5. A tempered glass article according to claim 1, wherein the apex of the arc portion is located closer to the first main surface than the center of the tempered glass substrate in the thickness direction.

6. The tempered glass article according to claim 1, wherein the lightness L of the protective layer is ＊ A tempered glass article having a modulus of elasticity of 0 or greater and 80 or less.

Images