Glass plate, method for manufacturing same, in-vehicle display device, and method for selecting glass plate

Abstract

The present invention relates to a glass plate having a first main surface and a second main surface facing the first main surface, the first main surface having an uneven structure in at least a portion thereof, the visibility index value (T) of the outermost surface of a region having the uneven structure on the first main surface side being 0.85 or more, and the glare index value (S) being 0.80 or more, the average coefficient of dynamic friction (COF) is 0.50 or less, the amount of friction change (delta) exceeds-0.210, and the lightness (L *) value is 4.7 or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a glass sheet and a method for manufacturing the same, a display device for vehicle, and a method for selecting a glass sheet. BACKGROUND

[0002] Conventionally, a cover composed of a transparent base such as a glass sheet is provided on the display surface side of a display device such as an LCD (Liquid Crystal Display) device in order to protect the display device.

[0003] However, in the case where such a transparent base is provided on a display device, there is a case where an article provided on the periphery is reflected when visually recognizing a display image of the display device through the transparent base. If the transparent base is reflected in this way, the visual recognizer of the display image has difficulty in visually recognizing the display image, and an unpleasant impression is left. In particular, in the case of a cover glass in a display device for vehicle, the distance from the driver to the display device is fixed. Therefore, when a strong light source such as sunlight is reflected, the visual recognition of the display image becomes very difficult, the necessary information cannot be read, and the possibility of hindering the driving is high.

[0004] Therefore, in order to suppress such reflection, for example, a method of performing an anti-glare treatment of forming a concave-convex shape on the surface of the transparent base is adopted.

[0005] In this regard, Patent Literature 1 discloses a method of evaluating the reflection on a display device using a special device. However, the optical characteristics required for a cover glass and the like in a display device for vehicle are not limited to reducing reflection. That is, in the case of a cover glass in a display device for vehicle, it is required to have optical characteristics of each prescribed level in resolution or visual recognition, reflection image diffusion, and glare, and the like. Therefore, when selecting a transparent base such as a glass sheet, it is not enough to consider only one kind of optical characteristics, and it is often necessary to consider a plurality of optical characteristics at the same time.

[0006] Therefore, Patent Literature 2 discloses that when evaluated using three index values of a resolution index value T, a reflection image diffusion index value R, and a glare index value S, a glass sheet having appropriate resolution, reflection image diffusion, and glare prevention properties as a display device for vehicle can be obtained when these index values satisfy a specific range.

[0007] In addition, Patent Literature 3 discloses that a glass sheet having excellent color reproducibility can be obtained when, in addition to the visual recognition index value T, the reflection image diffusion index value R, and the glare index value S, the transmission haze also satisfies a specific range.

[0008] PRIOR ART DOCUMENTS

[0009] PATENT LITERATURE

[0010] Patent Literature 1: Japanese Patent Application Laid-Open No. 2007-147343

[0011] Patent Literature 2: Japanese Patent No. 5867649

[0012] Patent Literature 3: Japanese Patent No. 7067077 SUMMARY

[0013] For the above, the cover glass and the like in the display device for vehicle is not only for visual recognition, but also sometimes touched as a touch panel, and it is expected that such opportunities will increase in the future.

[0014] As an index for evaluating the touch feeling of the touch panel, for example, as disclosed in Non-Patent Literature 1, arithmetic average roughness and dynamic friction coefficient are used.

[0015] However, it was found by the present inventors and the like that the index of the actual touch feeling is not enough only by the arithmetic average roughness and the dynamic friction coefficient described above. Therefore, the present inventors and the like focused on the sliding motion in particular, and researched a new method for quantitatively evaluating the touch feeling.

[0016] Therefore, an object of the present application is to provide a glass sheet which maintains appropriate visual recognition and has excellent touch feeling at the time of sliding motion, and a manufacturing method thereof. In addition, an object is also to provide a display device for vehicle using the glass sheet described above and a method for selecting the glass sheet described above.

[0017] The present inventors and the like conducted intensive research on the above problem, and as a result, it was found that, at the time of sliding motion, in addition to the dynamic friction coefficient, the change in friction at the terminal portion at the time of stopping sliding is also important, and thus the present application was completed. In addition, in order to achieve the desired change in friction, the shape of the surface of the glass sheet is important, and a method for achieving the shape was also found.

[0018] That is, the present application relates to the following [1] to

[19] .

[0019] [1] A glass sheet having a first main surface and a second main surface opposite to the first main surface,

[0020] the first main surface has a concavo-convex structure at least in a part thereof,

[0021] a value T of a visual recognition index of the surface of the region having the concavo-convex structure on the first main surface side is 0.85 or more, a value S of a glare index is 0.80 or more, an average dynamic friction coefficient COF is 0.50 or less, and a change in friction delta exceeds -0.210,

[0022] the glass sheet has a lightness L in a specular component elimination (SCE) mode measured by a method according to ASTM E313-73 standard＊ a value of 4.7 or less,

[0023] The above visual recognition index value T, the above glare index value S, the above average dynamic coefficient of friction COF, and the above friction variation delta are each quantified by the following method.

[0024] Visual recognition index value T: Using SMS-1000 manufactured by DM&S Co., Ltd., a glass sheet is disposed above a slit-shaped white light source having a length of 40 mm and a width of 0.1 mm at a position 30 mm above the light source, with the above first main surface side being the light source side. The brightness of the surface of the region having the above irregular structure is measured from the above second main surface side of the glass sheet. A camera lens is used with an aperture of 5.6 and a lens having a focal length of 16 mm, and the distance from the surface of the above first main surface side of the glass sheet to the above camera lens is set to 550 mm. The direction parallel to the thickness direction of the glass sheet is set to an angle θ = 0°, the average value of the brightness in the range of an angle θ = 0° ± 0.1° is set to T1, the average value of the brightness in the range of an angle θ = 0.7° ± 0.1° is set to T2, and the average value of the brightness in the range of an angle θ = -0.7° ± 0.1° is set to T3, and the value calculated by the following equation (1) is set to the visual recognition index value T.

[0025] Visual recognition index value T = 1 - (T2 + T3) / (2 x T1) Equation (1)

[0026] Glare index value S: The glass sheet is disposed with the above second main surface in contact with the display surface side of a display device having a resolution of 264 ppi. In a state in which the display device displays an image of a single color of green composed of RGB (0, 255, 0), image analysis is performed using SMS-1000 manufactured by DM&S Co., Ltd. disposed on the above first main surface side of the glass sheet, and the Sparkle value of the surface of the region having the above irregular structure calculated is set to the glare S a . The distance d between the above first main surface side of the glass sheet and the above SMS-1000 manufactured by DM&S Co., Ltd. is 540 mm, and a camera lens is used with an aperture of 5.6 and a lens having a focal length of 50 mm. In addition, image analysis is also performed under the same conditions for a glass substrate (VRD140 glass; manufactured by AGC Glass Europe Co., Ltd.) having the same thickness as the glass sheet, and the Sparkle value calculated is set to the glare S s . The value of S a and S s is calculated by the following equation (2) and is set to the glare index value S.

[0027] Glare index value S = 1 - (S a / Ss ) Equation (2)

[0028] Average dynamic friction coefficient COF, friction variation delta: In a static-dynamic friction measuring machine, in an environment of room temperature 23°C, humidity 21%, on the surface of the region having the concavo-convex structure on the first main surface side of the glass plate, a simulated finger was made to slide at a scanning distance of 50 mm, a load of 100 g, and a scanning speed of 100 mm / sec. The data acquisition frequency was 1 kHz. The simulated finger was made of polyurethane, and the contact portion with the surface had linear convex portions formed at an interval of 0.5 mm in a direction at right angles to the sliding direction in an area of 10 x 15 mm. Here, from the time when the dynamic friction coefficient became the maximum, the time when the dynamic friction coefficient first became 0 or less was set as the motion start time, and the time when the dynamic friction coefficient first became 5 or less after the time represented by {(the motion start time) + (0.75 x the scanning distance / the scanning speed)} was set as the motion end time, the value calculated by the following Equation (3) was set as the average dynamic friction coefficient COF, and the value calculated by the following Equation (4) was set as the friction variation delta.

[0029] Average dynamic friction coefficient COF = average value of the dynamic friction coefficient at the time of (the middle time of the motion start time to the motion end time) ± 0.2 seconds Equation (3)

[0030] Friction variation delta = (the maximum dynamic friction coefficient after the motion end time) - (the average dynamic friction coefficient COF) Equation (4)

[0031] [2] The glass plate according to the above [1], wherein the first main surface further has an antireflection film at least in part,

[0032] the antireflection film covers at least a part of the concavo-convex structure,

[0033] the light transmittance measured on the surface of the region having the antireflection film in the glass plate on the first main surface side is 20 to 85%,

[0034] the b value of the transmission color under D65 light source measured according to JIS Z 8729 (2004) for the region having the antireflection film in the glass plate is 5 or less, ＊

[0035] the light reflectance measured on the surface of the region having the antireflection film covering the concavo-convex structure in the glass plate on the first main surface side is 1% or less,

[0036] the sheet resistance of the antireflection film is 10 4 Ω / D or more. ​

[0037] [3] The glass sheet according to the above [2], wherein a transmittance haze of a surface layer of a region having the concavo-convex structure and the antireflection film on the first main surface side is 15% or more as measured by a method according to JIS K 7136 (2000).

[0038] [4] The glass sheet according to the above [2] or [3], wherein the antireflection film is a stacked structure in which dielectric layers having different refractive indexes are alternately stacked two or more layers,

[0039] a main component of the dielectric layers in the stacked structure is an oxide of at least one selected from Si, Nb, Ti, Zr, Ta, Al, Sn, and In, or a nitride of at least one of Si and Al,

[0040] at least one of the dielectric layers has dispersed therein at least one kind of fine particles selected from Ag, Mo, W, Cu, Au, Pd, Pt, Ir, Ni, Co, Fe, Cr, C, TiC, SiC, TiN, and CrN.

[0041] [5] The glass sheet according to any one of the above [2] to [4], wherein the antireflection film is a stacked structure in which layers having different refractive indexes are alternately stacked two or more layers,

[0042] a main component of at least one of the layers in the stacked structure is an oxide of Si,

[0043] a main component of at least one other of the layers in the stacked structure is a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In,

[0044] a content ratio of the element of the Group B in the mixed oxide with respect to a total of the element of the Group A and the element of the Group B is less than 50 mass%.

[0045] [6] The glass sheet according to any one of the above [2] to [5], wherein a surface roughness curve of a surface layer of a region having the concavo-convex structure and the antireflection film on the first main surface side has an element average length Rsm of a roughness curve of less than 26 μm, an arithmetic average roughness Ra of 0.12 μm or more, a skewness Rsk of -1 to 1, and a kurtosis Rku of 2 to 4.

[0046] [7] The glass sheet according to the above [1], wherein a transmittance haze of a surface layer of a region having the concavo-convex structure on the first main surface side is less than 15% as measured by a method according to JIS K 7136 (2000).

[0047] [8] The glass sheet according to any one of the above [1] to [7], wherein the element average length Rsm of the roughness curve in the surface roughness of the uppermost surface of the region of the first main surface side having the concavo-convex structure is 26 μm or more, the skewness Rsk is -4 to -1.5, and the kurtosis Rku is 5 to 20.

[0048] [9] The glass sheet according to any one of the above [1], [7], or [8], wherein the first main surface further has an antireflection film at least in part thereof,

[0049] the antireflection film covers at least a part of the concavo-convex structure,

[0050] the antireflection film is a stacked structure in which a low-refractive-index layer and a high-refractive-index layer are alternately stacked two or more times,

[0051] the main component of the high-refractive-index layer is at least one selected from the group consisting of SiN, Ti02, Nb205, Ta205, and Zr02.

[0052]

[10] The glass sheet according to any one of the above [1] to [9], wherein a print layer is provided at least in part on the second main surface.

[0053]

[11] The glass sheet according to any one of the above [1] to

[10] , wherein the glass sheet is a chemically strengthened glass.

[0054]

[12] The glass sheet according to any one of the above [1] to

[11] , which is used as a cover glass for a display device for a vehicle.

[0055]

[13] A display device for a vehicle, comprising a cover glass made of the glass sheet according to the above

[12] and a display panel.

[0056]

[14] A method for manufacturing a glass sheet, which is the method for manufacturing the glass sheet according to any one of the above [1] to

[12] ,

[0057] the glass sheet has a first main surface and a second main surface opposite to the first main surface,

[0058] the method for manufacturing the glass sheet includes forming a concavo-convex structure at least in part on the first main surface.

[0059]

[15] The method for manufacturing a glass sheet according to the above

[14] , wherein the forming of the concavo-convex structure includes: immersing the glass sheet in a solution containing potassium fluoride and hydrogen fluoride; and then immersing the glass sheet in a solution containing hydrogen fluoride;

[0060] Further comprising forming an anti-reflection film in a manner to cover at least a part of the concavo-convex structure.

[0061]

[16] The glass sheet manufacturing method according to the above

[14] , wherein the forming of the concavo-convex structure includes: roughening the first main surface of the glass sheet by jetting a slurry thereon; and then etching the glass sheet by immersing it in a solution containing hydrogen fluoride.

[0062]

[17] The glass sheet manufacturing method according to the above

[16] , wherein the jetting angle of the slurry is 70° or less with respect to the first main surface.

[0063]

[18] The glass sheet manufacturing method according to the above

[16] or

[17] , wherein the forming of the concavo-convex structure includes: immersing the glass sheet in a solution containing potassium fluoride and hydrogen fluoride; and then immersing the glass sheet in a solution containing hydrogen fluoride; further comprising forming an anti-reflection film in a manner to cover at least a part of the concavo-convex structure.

[0064]

[19] A method of selecting the glass sheet according to any one of the above [1] to

[12] .

[0065] According to the present application, it is possible to provide a glass sheet which maintains appropriate visual recognition and has excellent tactile sensation during sliding action, and a manufacturing method thereof. It is also possible to provide a display device for vehicle using the above glass sheet and a method of selecting the above glass sheet. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 is a schematic view showing an example of a measuring device used when measuring a visual recognition index value T.

[0067] Figure 2 is a schematic view showing an example of a measuring device used when measuring a glare index value S.

[0068] Figure 3 is a schematic view showing an example of a measuring device used when measuring a reflection image diffusion index value R. DETAILED DESCRIPTION

[0069] The present application will be described in detail below. Note that in the present specification, "~" indicating a numerical range is used in the meaning that the numerical values recited before and after it are included as lower limit values and upper limit values.

[0070] GLASS SHEET

[0071] The glass sheet of the present application has a first main surface and a second main surface opposite to the first main surface, and the first main surface has a concavo-convex structure at least in a part thereof.

[0072] The visual recognition index value T of the surface of the region having the uneven structure on the first main surface side is 0.85 or greater, and the glare index value S is 0.80 or greater. In addition, the average dynamic friction coefficient COF of the surface is 0.50 or less, and the friction variation delta exceeds -0.210.

[0073] Further, the glass sheet has a lightness L ＊ value of 4.7 or less.

[0074] 〈Average dynamic friction coefficient COF, friction variation delta〉

[0075] The average dynamic friction coefficient COF of the surface of the region having the uneven structure on the first main surface side of the glass sheet of the present embodiment is 0.50 or less, and the friction variation delta exceeds -0.210.

[0076] Here, the average dynamic friction coefficient COF and the friction variation delta are values derived by the following measurement method. Note that the average dynamic friction coefficient COF and the friction variation delta in the present specification preferably use the average value of measurements at any 3 points on the diagonal. Among these, as the arbitrary measurement points, sites at which extreme deviation values are obtained are excluded.

[0077] (Measurement method)

[0078] In a static-dynamic friction measurement machine, in an environment of room temperature 23°C and humidity 21%, the dynamic friction coefficient was measured by sliding the simulation finger at a scan distance of 50 mm, a load of 100 g, and a speed of 100 mm / sec on the surface of the region having the uneven structure on the first main surface side of the glass sheet. The data acquisition frequency was 1 kHz.

[0079] The simulation finger was made of polyurethane, and the contact portion with the surface of the glass sheet was formed with linear protrusions at 0.5 mm intervals in a direction at right angles to the sliding direction in an area of 10 x 15 mm.

[0080] Here, from the time at which the dynamic friction coefficient became the maximum, the time at which the dynamic friction coefficient first became 0 or less was set as the movement start time, and after the time represented by {(the movement start time) + (0.75 x the scan distance / the scan speed)}, the time at which the dynamic friction coefficient first became 5 or less was set as the movement end time. Furthermore, the value calculated by the following equation (3) was set as the average dynamic friction coefficient COF, and the value calculated by the following equation (4) was set as the friction variation delta.

[0081] Average dynamic friction coefficient COF = average value of dynamic friction coefficient at ± 0.2 seconds from the middle of the time from the start of the movement to the end of the movement

[0082] Friction variation delta = (maximum dynamic friction coefficient after the end of the movement) - (average dynamic friction coefficient COF)

[0083] Note that the scan distance and scan speed in the equation for finding the end of the movement are 50 mm and 100 mm / sec, respectively, as described as the sliding conditions for the simulated finger.

[0084] The average dynamic friction coefficient COF is effective as an evaluation of the finger sliding when sliding on the surface of the glass plate, i.e., the smoothness.

[0085] The average dynamic friction coefficient COF is 0.50 or less, preferably 0.10 to 0.50. Here, from the viewpoint of making the finger sliding when sliding smooth, the average dynamic friction coefficient COF is 0.50 or less, preferably 0.45 or less, more preferably 0.40 or less, and further preferably 0.35 or less. On the other hand, the lower limit of the average dynamic friction coefficient COF is not particularly limited, but from the viewpoint of imparting a sliding operation feeling to the user, it is preferably 0.10 or more, more preferably 0.15 or more, and further preferably 0.20 or more.

[0086] In addition, it was found through the research by the present inventors and others that at the end of the sliding operation on the surface of the glass plate, the so-called floating feeling in which the feeling of the finger stopping is weak is related to the friction variation delta, and it is effective for the value of the friction variation delta to be a certain value or more.

[0087] The friction variation delta is more than -0.210, preferably more than -0.210 and 0.01 or less. Here, from the viewpoint of suppressing the feeling of the finger sticking at the end of the sliding operation and achieving a smooth finger release feeling, the friction variation delta is more than -0.210, preferably -0.205 or more, more preferably -0.200 or more, further preferably -0.15 or more, and still further preferably -0.10 or more. On the other hand, the upper limit of the friction variation delta is not particularly limited, but from the viewpoint of imparting an operation feeling of ending the sliding to the user, it is preferably -0.01 or less, more preferably -0.02 or less, and further preferably -0.03 or less.

[0088] More specifically, the average dynamic friction coefficient COF and the friction variation delta are preferably in the following combinations.

[0089] (i) the average dynamic friction coefficient COF is 0.35 or less, and the friction variation delta is -0.200 or more.

[0090] (ii) the average dynamic friction coefficient COF is 0.40 or less, and the friction variation delta is -0.100 or more.

[0091] Further preferable modes of the above combination can adopt the respective preferable upper and lower limits of the average dynamic friction coefficient COF and the friction variation delta.

[0092] In order for the average dynamic friction coefficient COF and the friction variation delta to satisfy the above ranges, for example, the shape of the concavo-convex structure on the first main surface side of the glass sheet is set to a prescribed range.

[0093] For example, when the convex portions in the concavo-convex structure of the above surface are sharp, the contact with the user's finger becomes contact in a dispersed plurality of points, and thus the dynamic friction coefficient becomes low, and the smooth feeling during sliding action is good.

[0094] On the other hand, by refining the concavo-convex structure of the above surface, the period of the concavo-convex is shortened, and more convex portions are formed, and thus the friction variation at the end of the sliding action can be increased, and a smooth feeling of finger release can be achieved.

[0095] Note that even in the case where an antireflection film, a stain-proof film, or the like is formed in a manner of covering the concavo-convex structure, the surface structure of the antireflection film, the stain-proof film, or the like becomes a structure imitating the above concavo-convex structure. Thus, by setting the shape of the concavo-convex structure to a prescribed range, the concavo-convex shape of the topmost surface of the glass sheet can be suppressed.

[0096] One example of the specific concavo-convex shape in the topmost surface of the glass sheet for satisfying the desired ranges of the average dynamic friction coefficient COF and the friction variation delta will be described later.

[0097] 〈Visual Discriminability Index Value T〉

[0098] The visual discriminability (Clarity) in the present embodiment indicates that when a display image is visually discriminated through the glass sheet, an image can be obtained that is consistent with the display image to what extent. This is related to the judgment result of the visual discriminability (resolution) obtained by the visual observation of an observer, and it is confirmed that behavior close to human vision is exhibited.

[0099] For example, the visual discriminability of the glass sheet exhibiting a small (close to 0) value of the visual discriminability index value T is poor, and, on the contrary, the visual discriminability of the glass sheet exhibiting a large value of the visual discriminability index value T is good. Thus, this visual discriminability index value T can be used as a quantitative index when judging the visual discriminability of the glass sheet.

[0100] The visual discrimination index value T in the present embodiment is quantified by the following method. Note that the visual discrimination index value T in the present specification preferably uses the average value of measurements at any 3 points on the diagonal line. Among these, as the arbitrary measurement points, sites that yield extreme deviation values are excluded.

[0101] The SMS-1000 manufactured by Display-Messtechnik & Systeme was used as the analysis device, and a glass plate was disposed above the slit-shaped white light source having a length of 40 mm and a width of 0.1 mm at a position of 30 mm, with the first main surface side being the light source side. Then, the luminance of the surface of the region having the concavo-convex structure was measured from the second main surface side of the glass plate.

[0102] The camera lens was used at an aperture of 5.6, and a lens having a focal length of 16 mm was used, and the distance from the surface of the first main surface side of the glass plate to the camera lens was set to 550 mm.

[0103] The direction parallel to the thickness direction of the glass plate was set to an angle θ = 0°, the average value of the luminance in the range of an angle θ = 0° ± 0.1° was set to T1, the average value of the luminance in the range of an angle θ = 0.7° ± 0.1° was set to T2, and the average value of the luminance in the range of an angle θ = -0.7° ± 0.1° was set to T3, and the value calculated by the following formula (1) was set to the visual discrimination index value T.

[0104] Visual discrimination index value T = 1 - (T2 + T3) / (2 x T1) Formula (1)

[0105] More specifically, reference is made to Figure 1 One mode of the measurement method of the visual discrimination index value T of the glass plate 50 will be described.

[0106] The measurement device 70A has a light source 71 and a detector (analysis device) 75, and the sample to be measured, i.e., the glass plate 50, is disposed in the measurement device 70A. The glass plate 50 has a first main surface 52 and a second main surface 53 having a concavo-convex structure.

[0107] The light source 71 irradiates the first light in a direction parallel to the thickness direction of the glass plate 50 from the first main surface 52 side of the glass plate 50, and the detector (analysis device) 75 on the second main surface 53 side of the glass plate 50 detects and analyzes the luminance of the transmitted light of the first light that has transmitted through the glass plate 50.

[0108] The direction parallel to the thickness direction of the glass sheet 50 is set to an angle θ = 0°, and the visual recognition index value T of the glass sheet 50 is calculated by the above formula (1) using the average value (T1) of the luminance detected within the range of the angle θ = 0° ± 0.1°, the average value (T2) of the luminance detected within the range of the angle θ = 0.7° ± 0.1°, and the average value (T3) of the luminance detected within the range of the angle θ = -0.7° ± 0.1°.

[0109] Note that the negative (-) sign in the angle θ indicates an inclination counterclockwise with respect to the incident first light, and the positive (+) sign indicates an inclination clockwise with respect to the incident first light.

[0110] Note that, as the analysis device, the above SMS-1000 manufactured by DM&S Co., Ltd. (Display-Messtechnik & Systeme Co., Ltd.) is used, but in the case where a subsequent device of DM&S Co., Ltd. according to JIS C1006:2019 appears, the above subsequent device can be used.

[0111] In addition, as the camera lens, for example, a C1614A lens (manufactured by Ricoh Co., Ltd.) can be used.

[0112] As one of the optical properties of the glass sheet of the present embodiment, the above visual recognition index value T of the surface of the region having the concavo-convex structure is 0.85 or greater, preferably 0.86 or greater, more preferably 0.87 or greater, and is more preferably higher. The upper limit of the visual recognition index value T is 1.0.

[0113] The visual recognition index value T can be set to a desired range by, for example, the shape and density of the concavo-convex structure.

[0114] 〈Glare Index Value S〉

[0115] The glare (Anti-Sparkle) in the present embodiment indicates how much the unevenness of the bright spots generated due to the light (image) from the display image being scattered by the glass sheet surface when the light passes through the glass sheet and the scattered light interfering with each other can be observed. This is related to the judgment result of the glare by the visual observation of the observer, and confirms that the behavior close to the human vision is exhibited. For example, the glare of the glass sheet having a small glare index value S is significant, and, on the contrary, the glass sheet having a large glare index value S has a tendency to suppress the glare.

[0116] The glare index value S in the present embodiment is quantified by the following method. Note that the glare index value S in the present specification preferably uses the average value measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, the sites where extreme deviation values are obtained are excluded.

[0117] The glass plate was arranged so as to contact the second major surface side of the display surface side of the display device. In a state in which the display device displayed an image of a green monochrome color composed of RGB (0, 255, 0), image analysis was performed using the SMS-1000 manufactured by DM&S Co., Ltd. provided on the first major surface side of the glass plate, and a Sparkle value of the surface of the region having the uneven structure calculated was set as the glare S a .

[0118] The distance d between the SMS-1000 manufactured by DM&S Co., Ltd. and the surface of the first major surface side of the glass plate was 540 mm, and a lens having a focal length of 50 mm was used with an aperture of 5.6.

[0119] Image analysis was performed under the same conditions for a glass substrate (VRD140 glass; manufactured by AGC Glass Europe Co., Ltd.) of the same size as the glass plate, and a Sparkle value calculated was set as the glare S s .

[0120] A value calculated by the following formula (2) from the value of S a and S s was set as the glare index value S.

[0121] Glare index value S = 1 - (S a / S s ) Formula (2)

[0122] Note that, in a case where it is difficult to obtain the VRD140 glass as the glass substrate of the above-described reference sample, a glass substrate having a Sparkle value of 0.270 to 0.290 was used as the reference sample.

[0123] Here, the reason why the display device displays an image of a green monochrome color composed of RGB (0, 255, 0) is that it is a color having high visual acuity and is easily visually recognized.

[0124] In addition, when the distance d between the SMS-1000 manufactured by DM&S Co., Ltd. as the solid-state imaging device and the surface of the first major surface side of the glass plate was 540 mm, it corresponded to r = 10.8. The distance index r was represented by the following formula (2-1) using the focal length f of the solid-state imaging device and the distance d between the solid-state imaging device and the glass plate.

[0125] Distance index r = (distance d between the solid-state imaging device and the glass plate) / (focal length f of the solid-state imaging device) Formula (2-1)

[0126] More specifically, with reference to Figure 2 One mode of the measurement method of the glare index value S of the glass plate 50 will be described.

[0127] In the measurement device 70C, the measured sample, that is, the glass sheet 50 and a display device 54 having a resolution of 264 ppi are provided, and a detector 75 is disposed on the first main face 52 side of the glass sheet 50, which display device 54 is in contact with the second main face 53 of the glass sheet 50. As the display device 54, for example, an LCD panel can be cited. The display device 54 is caused to display an image of a green monochrome color composed of RGB (0, 255, 0), and the image is analyzed by the detector (analysis device) 75 with the glass sheet 50 interposed therebetween. A Sparkle value calculated from the result of the image analysis is set as the glare S a .

[0128] The value of the glare S a calculated under the same conditions for a glass substrate (VRD140 glass; manufactured by Asahi Glass Europe) of the same thickness as the glass sheet 50 as a reference sample is calculated as the glare index value S of the glass sheet by the above-described equation (2). s

[0129] Note that, as the solid-state imaging device, the SMS-1000 manufactured by DM&S (Display-Messtechnik & Systeme) was used, but in the case where a subsequent device of DM&S in accordance with JIS C1006:2019 appears, the subsequent device can be used for the analysis device.

[0130] In addition, as the camera lens, for example, the 23FM50SP lens (manufactured by TAMRON) can be used.

[0131] As one of the optical properties of the glass sheet of the present embodiment, the above-described glare index value S of the surface of the region having the concavo-convex structure is 0.80 or greater, preferably 0.81 or greater, and more preferably 0.82 or greater, and it is more preferable to be higher in order to improve the visual recognition of the information displayed by the display body. The upper limit of the glare index value S is 1.0.

[0132] The glare index value S can be set to a desired range depending on, for example, the shape and density of the concavo-convex structure.

[0133] 〈Reflection image diffusivity index value R〉

[0134] ​As an index of the optical properties of the glass sheet of the present embodiment, the reflection image diffusiveness (Reflection image diffusiveness index value) can be cited. The reflection image diffusiveness indicates to what extent the reflected image of an object (for example, illumination) placed at the periphery of the glass sheet coincides with the original object. This is related to the result of the judgment of the anti-glare property by the visual observation by the observer, and it is confirmed that the behavior close to the human vision is exhibited.

[0135] For example, the anti-glare property of the glass sheet in which the reflection image diffusiveness index value R exhibits a small (close to 0) value is poor, and, on the contrary, the anti-glare property of the glass sheet in which the reflection image diffusiveness index value R exhibits a large value (the larger the value is, the closer to 1) is good.

[0136] The reflection image diffusiveness index value R is quantified by the following method. Note that the reflection image diffusiveness index value R in the present specification preferably uses the average value measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, the sites at which extreme deviated values are obtained are excluded.

[0137] The brightness of the reflected light of the glass sheet is measured by using the SMS-1000 manufactured by DM&S Co., Ltd. to irradiate the glass sheet with light in the form of a slit having a width of 101 mm from the first main surface side. The camera lens uses a lens having a focal length of 16 mm with an aperture of 5.6, the distance from the surface of the glass sheet on the first main surface side to the camera lens is set to 300 mm, and the imaging scale is set to a range of 0.0276 to 0.0278.

[0138] When the direction parallel to the thickness direction of the glass sheet is set to an angle φ = 0°, the light is irradiated from an angle φ = 5.7° ± 0.1°, and the angle φ = -5.7° at which the total reflection occurs is set as the reference (angle α = 0°). When the average value of the brightness of the reflected light in the range of the angle α = 0° ± 0.1° is set to R1, the average value of the brightness of the reflected light in the range of the angle α = 0.5° ± 0.1° is set to R2, and the average value of the brightness of the reflected light in the range of the angle α = -0.5° ± 0.1° is set to R3, the value calculated by the following formula (5) is set as the reflection image diffusiveness index value R.

[0139] Reflection image diffusiveness index value R = (R2 + R3) / (2 x R1) Formula (5)

[0140] More specifically, reference is made to Figure 3 One mode of the measurement method of the reflection image diffusiveness index value R of the glass sheet 50 is described.

[0141] The measuring device 70B has a light source 71 and a detector (analysis device) 75, and a sample to be measured, i.e., the glass plate 50 is disposed in the measuring device 70B with the first main face 52 facing the light source 71 and the detector 75. A black plate 51 is provided on the side of the second main face 53 of the glass plate 50. The light source 71 irradiates the glass plate 50 with a slit-shaped second light 731 having a width of 101 mm. The detector (analysis device) 75 receives reflected light reflected at a prescribed angle from the first main face 52, and analyzes the brightness thereof.

[0142] At the time of measurement, the second light 731 is irradiated from the light source 71 of the measuring device 70B toward the glass plate 50. When a direction parallel to the direction of the normal line L of the glass plate 50 (the thickness direction of the glass plate) is taken as an angle φ = 0°, the second light 731 is irradiated toward the glass plate 50 at an angle of 5.7° inclined in the clockwise direction (φ = 5.7°) (indicated by φ in FIG. 8). Figure 3 Note that, since the actual measurement includes an error, the angle φ more accurately includes a range of 5.7° ± 0.1°.

[0143] Next, the detector (analysis device) 75 detects the normally reflected light (hereinafter referred to as "first reflected light 733") of the light incident on the first main face 52 of the glass plate 50, and analyzes and calculates the average value Rl of the brightness thereof.

[0144] Note that, in reality, since the angle of the first reflected light 733 with respect to the normal line L is - (the angle of incidence) °, the angle is -5.7° ± 0.1° (indicated by αl in FIG. 9). The negative (-) sign indicates that the angle is inclined counterclockwise with respect to the above-mentioned normal line L, and the positive (+) sign indicates that the angle is inclined clockwise with respect to the above-mentioned normal line. Figure 3

[0145] Here, when the direction inclined at -5.7° with respect to the normal line L is taken as a reference (angle α = 0°), the first reflected light 733 is in a range of an angle α = 0° ± 0.1° (= αl).

[0146] Similarly, taking the direction in which the first main face 52 of the glass plate 50 is inclined at -5.7° with respect to the normal line L as a reference (angle α = 0°), the average value R2 of the brightness of the reflected light (hereinafter referred to as "second reflected light 735") reflected at an angle α = 0.5° ± 0.1° and the average value R3 of the brightness of the reflected light (hereinafter referred to as "third reflected light 737") reflected at an angle α = -0.5° ± 0.1° are measured.

[0147] Using the respective brightnesses Rl, R2, and R3 obtained, the reflection image diffusivity index value R of the glass plate 50 is calculated by the above-mentioned formula (5).

[0148] ​Note that, as the analysis device, the above-described SMS-1000 manufactured by DM&S (Display-Messtechnik & Systeme) was used, but in the case where a subsequent device of DM&S in accordance with JIS C1006:2019 appears, the above-described subsequent device can be used.

[0149] In addition, as the camera lens, for example, a C1614A lens (manufactured by Ricoh Co., Ltd.) can be used.

[0150] As one of the optical properties of the glass sheet of the present embodiment, from the viewpoint of grasping the information displayed by the display body even in the presence of external light, the above-described reflection image diffusion index value R of the surface of the region having the concavo-convex structure is preferably 0.01 or greater, more preferably 0.012 or greater, and further preferably 0.015 or greater. On the other hand, from the viewpoint of suppressing "whiteout" in which the entire surface cannot be visually recognized due to scattered light in the case where very strong external light is irradiated, the reflection image diffusion index value R is preferably 0.95 or less, more preferably 0.8 or less, and further preferably 0.6 or less.

[0151] The reflection image diffusion index value R can be set to the desired range by, for example, the shape and density of the concavo-convex structure.

[0152] 〈Luminance L ＊ value〉

[0153] Even in the case where the glass sheet satisfies the optical properties of the above-described visual recognition index value T and the glare index value S, if the glass sheet itself is whitened, the visual recognition is affected. Therefore, the luminance L ＊ value of the glass sheet of the present embodiment in the SCE (Specular Component Excluded) mode measured by the method in accordance with ASTM E313-73 is 4.7 or less. Note that, the luminance L ＊ value in the present specification preferably uses the average value measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, sites where extreme deviation values are obtained are excluded.

[0154] If the luminance L ＊ value of the glass sheet of the present embodiment is 4.7 or less, the glass sheet itself is not whitened, and good visual recognition can be achieved. From the viewpoint of ensuring the transparency of the glass sheet, the above-described luminance L ＊ value is 4.7 or less, preferably 4.5 or less, and more preferably 4.3 or less. In addition, the lower limit is not particularly limited, but is generally 0.01 or greater.

[0155] The luminance L ＊The value is a value measured in a specular excluded (SCE) manner according to the method of ASTM E313-73, excluding specular reflected light and measuring only diffused reflected light. The results when the user visually evaluates the whiteness of the glass sheet in terms of the lightness L ＊ values are in good agreement. Therefore, the L ＊ a ＊ b ＊ The lightness L ＊ in the color specification system is considered to be an index of the whiteness of the glass sheet.

[0156] The above lightness L ＊ value of the glass sheet of the present embodiment can be reduced by reducing the value of the transmittance haze of the glass sheet. In addition, it has been newly found that it can be reduced by forming a specific absorption-type antireflection film in a manner of covering the concavo-convex structure provided on the first main surface side.

[0157] <First Embodiment • Second Embodiment>

[0158] The first main surface of the glass sheet of the present embodiment has a concavo-convex structure in at least a part thereof. The concavo-convex structure functions as an antiglare (AG) function, and imparts antiglare properties to the glass sheet.

[0159] It has been conceived through the research of the present inventors that, as one mode of the glass sheet of the present embodiment, for example, the following first embodiment and second embodiment can be cited.

[0160] • First Embodiment

[0161] In the first embodiment, the first main surface of the glass sheet further has an antireflection film covering at least a part of the concavo-convex structure in at least a part thereof. Here, the light transmittance measured at the outermost surface on the first main surface side of the region of the glass sheet having the above antireflection film is 20 to 85%, and the b ＊ value of the transmission color measured according to JIS Z 8729 (2004) under D65 light source is 5 or less in the above region. In addition, the light reflectance measured at the outermost surface on the first main surface side of the region of the glass sheet having the antireflection film covering the concavo-convex structure is 1% or less, and the sheet resistance of the antireflection film is 10 4 Ω / D or more.

[0162] • Antireflection Film

[0163] In the first embodiment, the antireflection film can cover at least a part of the concavo-convex structure, and it is preferable to cover the region of the glass sheet that is visually recognized and touched for sliding action or the like. In the case where the concavo-convex structure is formed in all regions that are visually recognized and touched, it is preferable that the antireflection film is formed in all of these regions.

[0164] Generally, by providing the glass sheet with an antireflection film, a reduction in reflectance can be achieved, and glare caused by the reflection of light can be reduced. In addition, in the case where the glass sheet having the antireflection film is used for a display device, the transmittance of light from the display device can be increased, and the visual recognition of the image display device can be improved.

[0165] As is apparent from the above, by providing the antireflection film described below in the present embodiment, even in the case where the transmittance haze described later is high, the lightness L of the glass sheet can be reduced ＊ It should be noted that the influence of the provision of the antireflection film on the visual recognition index value T and the glare index value S is extremely small. Therefore, even in the case where the antireflection film is formed, the values of the visual recognition index value T and the glare index value S of the surface of the region having the concave-convex structure of the glass sheet after the formation of the antireflection film can be considered to be the same as the above-mentioned visual recognition index value T and the glare index value S before the formation of the antireflection film, respectively.

[0166] The antireflection film is a laminated structure in which dielectric layers having different refractive indexes from each other are alternately laminated two or more layers. By laminating the dielectric layers having different refractive indexes from each other, the reflection of light can be suppressed.

[0167] The antireflection film can be laminated in the order of a high-refractive-index layer, a low-refractive-index layer from the first main surface of the glass sheet, or can be laminated in the order of a low-refractive-index layer, a high-refractive-index layer. In addition, in the case where the number of layers is three or more, the refractive indexes of all the layers need not be different.

[0168] For example, in the case of a three-layer laminated structure, the layers can be laminated in the order of a low-refractive-index layer, a high-refractive-index layer, a low-refractive-index layer from the first main surface of the glass sheet, or can be laminated in the order of a high-refractive-index layer, a low-refractive-index layer, a high-refractive-index layer. Here, in the former case, the two low-refractive-index layers can have the same refractive index, respectively, and in the latter case, the two high-refractive-index layers can have the same refractive index, respectively. The same applies to the case where the number of layers is four or more.

[0169] It should be noted that, in the present specification, the high-refractive-index layer is, for example, a layer having a refractive index of 1.9 or more at a wavelength of 550 nm, and the low-refractive-index layer is a layer having a refractive index of 1.6 or less at a wavelength of 550 nm. In addition, it can be configured to be a layer having a refractive index of 1.2 to 1.4 at a wavelength of 550 nm, which contains hollow particles or voids mixed in the matrix of the layer.

[0170] As a preferable one of the antireflection film, fine particles having light-absorbing ability can be dispersed in the dielectric layer. As the fine particles having light-absorbing ability, fine particles having a high light-absorbing ability in the entire wavelength region of visible light are used.

[0171] In the present embodiment, by using a fine particle having a high light absorption ability in the entire wavelength region of visible light as the fine particle dispersed in the dielectric layer, yellowing of transmitted light can be more effectively prevented.

[0172] Specifically, at least one selected from the group consisting of Ag, Mo, W, Cu, Au, Pd, Pt, Ir, Ni, Co, Fe, Cr, C, TiC, SiC, TiN and CrN is preferable as the fine particle.

[0173] The above group is high in redox potential and has a low possibility of forming an oxide fine particle by reacting with the surrounding oxide. In addition, the light absorption ability is strong, and sufficient light absorption is produced by adding a small amount of the fine particle, so the possibility of the fine particles being adsorbed to each other and macroscopically producing electrical conductivity is also low. In addition, there is an advantage that it is relatively easy to obtain. Therefore, at least one fine particle selected from the above group is preferable.

[0174] Note that the fine particle dispersed in the dielectric layer can be only one of the above, or two or more.

[0175] In addition, the example exemplified as the option of the fine particle is high in electrical conductivity, but since the fine particle is dispersed in the dielectric layer, the absorption-type anti-reflection film is insulating.

[0176] The fine particle can be dispersed in the high refractive index layer, can be dispersed in the low refractive index layer, or can be dispersed in both. The number of layers of the dielectric layer in which the fine particle is dispersed is not particularly limited, and can be one layer or two or more layers.

[0177] It is preferable that the fine particle be dispersed in the dielectric layer other than the outermost dielectric layer constituting the absorption-type anti-reflection film. Note that the dielectric layer in which the fine particle is dispersed affects the light transmittance and light reflectance measured at the outermost surface of the glass sheet of the present embodiment and the sheet resistance of the absorption-type anti-reflection film.

[0178] The dielectric layer is preferably mainly composed of an oxide of at least one selected from the group consisting of Si, Nb, Ti, Zr, Ta, Al, Sn and In, or a nitride of at least one selected from the group consisting of Si and Al, and from the viewpoint of productivity and refractive index, it is more preferable that the high refractive index layer be composed of one selected from the group consisting of niobium oxide, tantalum oxide and silicon nitride and the low refractive index layer be composed of silicon oxide.

[0179] The reason is as described below.

[0180] The dielectric layer itself preferably has no light absorbing ability, and thus a substance having a small absorption ability in the entire visible wavelength region is preferable. In addition, in order to form a film having an antireflection property, if it is a low refractive index layer, the refractive index at a wavelength of 550 nm is preferably 1.5 or less, and if it is a high refractive index layer, the refractive index is preferably 1.8 or more. If selected from the above group, this condition is satisfied.

[0181] Note that, in the present specification, "mainly" means that the above oxide or nitride is included in the dielectric layer at a rate of 70% by mass or more.

[0182] The dielectric layer is appropriately selected in terms of the material of the oxide or nitride so as to be the desired refractive index layer (high refractive index layer, low refractive index layer). Note that the dielectric layer is appropriately selected in terms of the material so as to be the desired refractive index layer (high refractive index layer, low refractive index layer) including the refractive index of the fine particles.

[0183] Note that the dielectric layer can be composed of only one of the above oxides or nitrides, or can be composed of two or more.

[0184] Based on the above, as a preferable embodiment of the absorption-type antireflection film, the main component of the dielectric layer in the stacked structure is an oxide selected from at least one of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, or a nitride of at least one of Si and Al. Furthermore, fine particles selected from at least one of Ag, Mo, W, Cu, Au, Pd, Pt, Ir, Ni, Co, Fe, Cr, C, TiC, SiC, TiN, and CrN are dispersed in at least one of the above dielectric layers.

[0185] As another mode of the absorption-type antireflection film, one layer constituting the stacked structure is composed of a mixed oxide of at least one selected from Group A composed of Mo and W and at least one selected from Group B composed of Si, Nb, Ti, Zr, Ta, Al, Sn, and In. Here, the mixed oxide preferably has a content ratio (hereinafter referred to as Group B content ratio) of the element of Group B included in the mixed oxide with respect to the total of the element of Group A included in the mixed oxide and the element of Group B included in the mixed oxide of less than 50% by mass.

[0186] The main component of the other layer constituting the stacked structure is an oxide of Si, i.e., composed of SiO2.

[0187] As a light-transmitting film having light absorbing ability and insulating property, a half-tone mask used in the field of semiconductor production is known. As the half-tone mask, a Mo-SiO xAn oxygen-deficient film like a film. In addition, as a light-transmitting film having light-absorbing ability and insulating property, there is a narrow band gap film used in the field of semiconductor manufacturing.

[0188] However, these films have high light-absorbing ability in the short wavelength side of visible light, and thus the transmitted light is yellowish. Therefore, they are not suitable for cover glasses of image display devices.

[0189] In the present embodiment, by forming a layered structure of a layer in which the content of Mo is increased and a layer composed of SiO2, a glass sheet having light-absorbing ability, insulating property, and transmitted light which is not yellowish can be obtained.

[0190] Note that the main component in the present specification means a mixed oxide of at least one selected from Group A consisting of Mo and W and at least one selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, and the ratio of the mixed oxide in the material of the layer is 70% by mass or more. It also means that the ratio of the oxide of Si in the material of the layer is 70% by mass or more.

[0191] When the layer in which the above-described main component is a mixed oxide of Group A and Group B is referred to as layer (A-B-O), and the layer in which the main component is an oxide of Si is referred to as layer (SiO2), the content of B group in layer (A-B-O) is preferably less than 50% by mass, more preferably 45% by mass or less, further preferably 40% by mass or less, and particularly preferably 35% by mass or less, from the viewpoint of reducing the b ＊ value of the transmission color of the glass sheet under D65 light source.

[0192] The above-described absorption-type antireflection film can have layer (SiO2) and layer (A-B-O) stacked in this order from the first main surface side of the glass sheet, or layer (A-B-O) and layer (SiO2) stacked in this order. In addition, it can be a stacked structure in which layers having different refractive indexes are stacked in three or more layers. In this case, as long as at least one layer is layer (SiO2) and at least one other layer is layer (A-B-O), it can include layers other than these, or it can not include them. In addition, in the case where there are a plurality of layer (SiO2) and a plurality of layer (A-B-O), these layer (SiO2) can be the same as each other, or different from each other, and the same applies to layer (A-B-O). The same applies to the case where the number of layers is four or more.

[0193] The outermost layer of the absorption-type antireflection film is preferably layer (SiO2). This is because, in order to obtain low reflectivity, it can be easily produced if the outermost layer is layer (SiO2). In addition, in the case where a stain-proof film is further formed, from the viewpoint of the adhesion related to the durability of the stain-proof film, it is preferably formed on layer (SiO2). From this reason, the outermost layer of the absorption-type antireflection film is also preferably layer (SiO2).

[0194] In any of the above-described absorption-type antireflection films, the light reflectance measured at the surface on the first main surface side of the region where the absorption-type antireflection film covers the concavo-convex structure is preferably 1% or less, more preferably 0.8% or less, and further preferably 0.6% or less, from the viewpoint of preventing the reflection of external light into the glass sheet. The lower limit of the above-described light reflectance is not particularly limited, but is generally 0.1% or more.

[0195] Note that the above-described light reflectance in the present specification is a value measured in accordance with JIS Z 8701 (1999). Note that the light reflectance preferably uses an average value measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, sites where extremely deviated values are obtained are excluded.

[0196] In any of the above-described absorption-type antireflection films, the sheet resistance of the absorption-type antireflection film is preferably 10 6 Ω / D or more, more preferably 10 7 Ω / D or more, and further preferably 10 8 Ω / D or more. The upper limit of the sheet resistance of the absorption-type antireflection film is not particularly limited, but is generally 10 10 Ω / D or less.

[0197] Note that the sheet resistance of the absorption-type antireflection film in the present specification is a value measured in accordance with ASTM D257 or JIS K6271-6 (2008). Note that the sheet resistance of the antireflection film in the present specification preferably uses an average value measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, sites where extremely deviated values are obtained are excluded.

[0198] In order to set the sheet resistance of the absorption-type antireflection film, the light reflectance measured at the surface on the first main surface side of the region where the above-described absorption-type antireflection film is formed, the light transmittance, and the b ＊ value to the desired range, a suitable combination of the dielectric layer in the absorption-type antireflection film and the microparticles dispersed in the dielectric layer is preferably selected.

[0199] The sheet resistance when the dielectric layer in which the microparticles are dispersed is set to the dielectric layer in which the microparticles are not dispersed is preferably 10 8 Ω / D or more, more preferably 10 9 Ω / D or more.

[0200] On the other hand, the volume resistivity of the microparticles as a single substance is preferably 10 －5 Ωm or less.

[0201] The extinction coefficient of the dielectric layer in which the fine particles are dispersed is preferably in the range of 0.005 to 3, and more preferably in the range of 0.01 to 1 at a wavelength of 550 nm.

[0202] From the viewpoint of obtaining good absorption characteristics with a reasonable film thickness and achieving an appropriate light transmittance, the extinction coefficient is preferably 0.005 or more, and more preferably 0.01 or more. On the other hand, from the viewpoint of suppressing excessively strong absorption and excessively low light transmittance, the extinction coefficient is preferably 3 or less, and more preferably 1 or less. Thus, the transmitted light does not become yellow, and the b ＊ value of the glass sheet can also be in an appropriate range.

[0203] In addition, the dielectric layer formed on the dielectric layer in which the fine particles are dispersed preferably has a dielectric constant of 1.3 to 1.5 and a thickness of 30 to 150 nm.

[0204] As the glass sheet in which the above light transmittance, b ＊ value, light reflectance, and sheet resistance satisfy an appropriate range, for example, the following configurations can be cited.

[0205] An absorption-type antireflection film is formed on one main surface of a glass sheet, and a dielectric layer in which fine particles having light-absorbing ability are dispersed is formed on the other main surface.

[0206] The fine particles having light-absorbing ability include, for example, oxides such as chromium oxide and iron oxide, carbides such as chromium carbide and tungsten carbide, carbon black, and mica.

[0207] As the dielectric layer in which the fine particles having light-absorbing ability are dispersed, an epoxy-based resin, an acrylic-based resin, polyethylene terephthalate, polyether sulfone, polyarylate, polycarbonate, transparent ABS resin, phenol resin, acrylonitrile-butadiene-styrene resin, polyurethane, polymethyl methacrylate, polyethylene, polyvinyl butyral, polyether ether ketone, polyester, polypropylene, polyamide, polyimide, and a resin layer composed of a copolymer of monomers of these resins and copolymerizable monomers can be cited.

[0208] The light transmittance of the glass sheet

[0209] The light transmittance measured at the surface of the first main surface side of the region of the glass sheet in the first embodiment in which the above antireflection film is provided is preferably in the range of 20 to 85%. Here, in the case where the glass sheet having appropriate light-absorbing ability is used as a cover glass of a display device, from the viewpoint of improving the highlight contrast of the display device by suppressing reflection from the interface between the display device and the adhesive layer, the light transmittance is preferably 20% or more, more preferably 30% or more, and further preferably 40% or more, and is preferably 85% or less, more preferably 80% or less, and further preferably 75% or less.

[0210] It should be noted that the light transmittance values ​​described above in this specification are measured according to JIS Z 8701 (1999). Furthermore, the light transmittance values ​​described in this specification are preferably the average of measurements taken at any three points along the diagonal. These arbitrary measurement points exclude locations where extreme deviations in value were obtained.

[0211] ...the glass plate b ＊ value

[0212] From the viewpoint that the transmitted light does not yellow and can be appropriately used as a cover glass for a display device, b was measured on the area of ​​the glass plate in the first embodiment that has the aforementioned anti-reflective film. ＊ The value is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less. ＊ There is no specific lower limit to the value; it can be 0.

[0213] It should be noted that the glass plate described above (b) in this specification... ＊ The value is based on the transmitted color value measured under a D65 light source according to JIS Z 8729 (2004). Additionally, the b value in this specification... ＊ The preferred value is the average of measurements taken at any three points along the diagonal. These points are chosen as arbitrary measurement points, excluding those where extreme deviations are observed.

[0214] Transmitted Haze

[0215] Generally, the higher the transmitted haze value measured on the outermost surface of the region with the uneven structure and non-absorbent anti-reflective coating on the first main surface of the glass plate, the more light is scattered, and the stronger the whiteness of the glass plate's appearance. Therefore, regarding the whiteness of the glass plate's appearance, in order to measure the brightness L of the glass plate under the SCE method... ＊ The value is set below 4.7 to ensure that the above-mentioned transmission haze is less than 15%.

[0216] However, through the research of the inventors, it has been found that when the above-mentioned absorptive antireflective film is formed by covering an uneven structure, even if the transmission haze is 15% or more, the brightness L of the glass plate under the SCE method can be reduced. ＊ A value below 4.7 can suppress the whiteness of the glass plate.

[0217] Therefore, the transmission haze in the first embodiment can be 15% or more, 17% or more, or 20% or more. Furthermore, by reducing the brightness L of the glass plate... ＊ From a value perspective, the aforementioned transmission haze is preferably 35% or less, more preferably 32% or less, and even more preferably 30% or less.

[0218] Note that the transmission haze in the present specification indicates a loss of transmittance due to surface reflection (Fresnel reflection) caused by a difference in refractive index from air when light is incident on a glass sheet, and is measured by a method according to JIS K 7136 (2000). Note that the transmission haze in the present specification preferably uses an average value measured at any 3 points on a diagonal line. Among them, as the arbitrary measurement points, sites where extreme deviation values are obtained are excluded.

[0219] Specifically, the transmission haze is quantified by the following method.

[0220] Using a haze meter HZ-1 manufactured by SUGA Test Machine Co., a glass sheet is set on a light source with the first major surface side of the glass sheet as the light source side, and the transmitted light is measured from above the glass sheet.

[0221] When a direction parallel to the thickness direction of the glass sheet is set as an angle of 0°, light detected within ±2.5° is regarded as the transmitted light, and light detected in a range of less than -2.5° or more than +2.5° is regarded as the scattered light (loss of transmitted light). Then, a proportion of the scattered light with respect to a sum of the transmitted light and the scattered light, i.e., the total amount of light transmitted, is regarded as the transmission haze (%).

[0222] ·Rough structure-1

[0223] In the first embodiment, at least a part of one mode of the rough structure on the first major surface side of the glass sheet is covered with an absorption-type antireflection film. As for the surface roughness, the surface of the rough structure preferably satisfies one or more of the following (1) to (4), more preferably two or more, further preferably three or more, and particularly preferably all four. In addition, in a case where an absorption-type antireflection film, a stain-proof film, or the like is formed so as to cover the rough structure, the surface of the glass sheet after the absorption-type antireflection film, the stain-proof film, or the like is formed preferably satisfies one or more of the following (1) to (4), more preferably two or more, further preferably three or more, and particularly preferably all four. Note that since the absorption-type antireflection film or the like is formed so as to imitate the rough structure, the rough structure formed and the rough shape of the surface of the glass sheet on which the absorption-type antireflection film or the like is formed are substantially the same.

[0224] (1) The element average length Rsm of the roughness curve is less than 26 μm.

[0225] (2) The arithmetic average roughness Ra is 0.12 μm or more.

[0226] (3) The skewness Rsk is -1 to 1.

[0227] (4) The kurtosis Rku is 2 to 4.

[0228] The element average length Rsm of the roughness curve is the average of the lengths of the elements of the profile curve in the reference length, and is a value measured in accordance with JIS B 0601 (2013) (ISO 4287: 1997). The element average length Rsm of the roughness curve is preferably less than 26 μm, more preferably 24 μm or less, and further preferably 22 μm or less, from the viewpoint of reducing the interference of light due to the concavo-convex structure and increasing the glare index value S. On the other hand, the element average length Rsm of the roughness curve is preferably 5 μm or more, more preferably 7 μm or more, and further preferably 9 μm or more, from the viewpoint of increasing the reflection image diffusion index value R.

[0229] The arithmetic average roughness Ra is the average of the absolute values of Z(x) in the reference length, and is a value measured in accordance with JIS B 0601 (2013) (ISO 4287: 1997). The arithmetic average roughness Ra is preferably 0.12 μm or more, more preferably 0.13 μm or more, and further preferably 0.14 μm or more, from the viewpoint of increasing the reflection image diffusion index value R. On the other hand, the arithmetic average roughness Ra is preferably 0.3 μm or less, more preferably 0.28 μm or less, and further preferably 0.26 μm or less, from the viewpoint of ensuring the stability of the concavo-convex structure.

[0230] The skewness Rsk is the average of the cube of Z(x) in the reference length, which is made dimensionless by the cube of the root mean square height (Zq), and is a value measured in accordance with JIS B 0601 (2013). The skewness Rsk is preferably -1 to 1. Here, from the viewpoint of regulating the structure of the leading end portion of the concavo-convex structure and reducing the dynamic frictional resistance, the skewness Rsk is preferably -1 or more, more preferably -0.9 or more, and further preferably -0.8 or more, and on the other hand, is preferably 1 or less, more preferably 0.9 or less, and further preferably 0.8 or less.

[0231] The kurtosis Rku is the average of the fourth power of Z(x) in the reference length, which is made dimensionless by the fourth power of the root mean square height (Zq), and is a value measured in accordance with JIS B 0601 (2013). The kurtosis Rku is preferably 2 to 4. Here, from the viewpoint of regulating the sharpness of the leading end portion of the concavo-convex structure and reducing the dynamic frictional resistance, the kurtosis Rku is preferably 2 or more, more preferably 2.2 or more, and further preferably 2.4 or more, and on the other hand, is preferably 4 or less, more preferably 3.8 or less, and further preferably 3.6 or less.

[0232] Note that the element average length Rsm of the roughness curve, the arithmetic average roughness Ra, the skewness Rsk, and the kurtosis Rku in the present specification are preferably the average values measured at any 3 points on the diagonal line. Among them, as the arbitrary measurement points, sites at which extreme deviation values are obtained are excluded.

[0233] The glass sheet satisfying the above-described concavo-convex structure in the present embodiment is obtained, for example, by a frosted method, details of which will be described later.

[0234] In addition, in the manner of obtaining the above-described concavo-convex structure-1 in the first embodiment, the arithmetic average roughness Ra is large, and the element average length Rsm of the roughness curve, that is, the width of the concavo-convex is small. In addition, the skewness Rsk and the kurtosis Rku are close to the normal distribution. That is, the crack of the first embodiment is not deep, and thus, in order to maintain the visual discriminability index value T and the glare index value S to be values of at least a certain value, achieve the desired average dynamic friction coefficient COF and the friction variation amount delta, and also make the tactile sensation at the time of sliding good, the tip of the concavo-convex has to be sharp. Thus, there is a tendency that the transmission haze becomes high.

[0235] However, it has been found by the present inventors and the like that by covering at least a part of the concavo-convex structure with the above-described absorption-type anti-reflection film, even if the transmission haze is high, the whiteness of the substrate can be suppressed, and the luminance L ＊ value is set to 4.7 or less.

[0236] Concavo-convex structure-2

[0237] In the first embodiment, at least a part of one manner of the concavo-convex structure on the first main surface side of the glass sheet is covered with an absorption-type anti-reflection film. With respect to the surface roughness, the surface of the above-described concavo-convex structure preferably satisfies one or more of the following (1) to (3), more preferably two or more, and particularly preferably all three. In addition, in the case where an absorption-type anti-reflection film, a stain-proof film, or the like is formed so as to cover the concavo-convex structure, the surface of the most surface after the formation thereof preferably satisfies one or more of the following (1) to (3), more preferably two or more, and further preferably all three. Note that since the absorption-type anti-reflection film or the like is formed along the concavo-convex structure formed, the concavo-convex structure formed and the concavo-convex shape of the most surface where the absorption-type anti-reflection film or the like is formed are substantially the same.

[0238] (1) The element average length Rsm of the roughness curve is 26 μm or more.

[0239] (2) The skewness Rsk is -4 to -1.5.

[0240] (3) The kurtosis Rku is 5 to 20.

[0241] The element average length Rsm of the roughness curve is preferably 26 μm or more, more preferably 27 μm or more, further preferably 28 μm or more, still further preferably 30 μm or more, and most preferably 32 μm or more. On the other hand, from the viewpoint of avoiding the finger from touching the concave portion, the element average length Rsm of the roughness curve is preferably 50 μm or less, more preferably 48 μm or less, and further preferably 46 μm or less.

[0242] The skewness Rsk is preferably -4 to -1.5. Here, from the viewpoint of regulating the structure of the leading end portion of the concave-convex structure and reducing the dynamic frictional resistance, the skewness Rsk is preferably -4 or more, more preferably -3.8 or more, further preferably -3.6 or more, and on the other hand, is preferably -1.5 or less, more preferably -1.7 or less, further preferably -1.9 or less, and still further preferably -2.5 or less.

[0243] The kurtosis Rku is preferably 5 to 20. Here, from the viewpoint of regulating the sharpness of the leading end portion of the concave-convex structure and reducing the dynamic frictional resistance, the kurtosis Rku is preferably 5 or more, more preferably 6 or more, further preferably 7 or more, and still further preferably 11 or more, and on the other hand, is preferably 20 or less, more preferably 18 or less, and further preferably 16 or less.

[0244] As the shape of the concave-convex structure, the arithmetic average roughness Ra can be further considered. The arithmetic average roughness Ra is preferably 0.01 μm or more, more preferably 0.02 μm or more, and further preferably 0.03 μm or more. On the other hand, from the viewpoint of ensuring the stability of the concave-convex structure, the arithmetic average roughness Ra is preferably 0.30 μm or less, more preferably 0.28 μm or less, and further preferably 0.26 μm or less.

[0245] The glass sheet satisfying the above concave-convex structure-2 in the present embodiment is obtained, for example, by using a wet blasting method, the details of which are described later.

[0246] In the method of obtaining the above concave-convex structure-2 in the first embodiment, the element average length Rsm of the roughness curve, i.e., the width of the concave-convex is large. In addition, the skewness Rsk is large in the negative direction, i.e., the leading end of the concave portion that becomes a valley is sharp, and the leading end of the convex portion that becomes a hill is rounded. Furthermore, the kurtosis Rku is large, the symmetry of the shape of the concave portion and the convex portion deviates from the normal distribution, and the leading end of the convex portion is rounded.

[0247] By being configured in this way, while maintaining the visual discriminability index value T and the glare index value S to a value or more, the desired average dynamic coefficient of friction COF and the friction variation amount delta are achieved, the tactile sensation at the time of sliding is also good, and it is easy to maintain a low transmission haze. However, sometimes the transmission haze is 15% or more due to the optical properties, tactile sensation, etc. that are the object. Even in this case, by covering at least a portion of the concavo-convex structure with the above-described absorption-type anti-reflection film, it is possible to suppress the whiteness of the substrate, and it is possible to set the lightness L ＊ value in the SCE method to 4.7 or less.

[0248] • Second Embodiment

[0249] In the second embodiment, the transmission haze of the outermost surface of the region having the concavo-convex structure on the first main surface side of the glass sheet is less than 15% as measured by the method according to JIS K 7136 (2000).

[0250] • Transmission Haze

[0251] The transmission haze measured at the outermost surface of the region having the concavo-convex structure and an optional anti-reflection film on the first main surface side of the glass sheet is the greater the value, the stronger the light scattering, and the whiteness of the appearance of the glass sheet becomes stronger. Therefore, with respect to the whiteness of the appearance of the glass sheet, from the viewpoint of reducing the lightness L ＊ value of the glass sheet in the SCE method, the above-described transmission haze is preferably less than 15%, more preferably 14% or less, and further preferably 13% or less. The upper limit of the transmission haze is not particularly limited, but is generally 0.1% or more.

[0252] • Concavo-Convex Structure

[0253] In the second embodiment, with respect to the surface roughness, the surface of the concavo-convex structure on the first main surface side of the glass sheet preferably satisfies one or more of the following (1) to (3), more preferably two or more, and further preferably all three. Whether or not the above-described concavo-convex structure further has an anti-reflection film, a stain-proof film, etc. on at least a portion thereof is arbitrary as described above, but in the case where they are formed, the outermost surface after film formation preferably satisfies one or more of the following (1) to (3), more preferably two or more, and further preferably all three. Note that since the anti-reflection film, etc. is formed along the formed concavo-convex structure, the concavo-convex shape of the formed concavo-convex structure and the outermost surface of the formed anti-reflection film, etc. are substantially the same.

[0254] (1) The element average length Rsm of the roughness curve is 26 μm or more.

[0255] (2) The skewness Rsk is -4 to -1.5.

[0256] (3) The kurtosis Rku is 5 to 20.

[0257] The element average length Rsm of the roughness curve is the average of the lengths of the elements of the profile curve in the reference length, and is a value measured in accordance with JIS B 0601 (2013). The element average length Rsm of the roughness curve is preferably 26 μm or more, more preferably 27 μm or more, further preferably 28 μm or more, still further preferably 30 μm or more, and most preferably 32 μm or more. On the other hand, from the viewpoint of avoiding the finger from touching the concave portion, the element average length Rsm of the roughness curve is preferably 50 μm or less, more preferably 48 μm or less, and further preferably 46 μm or less.

[0258] The skewness Rsk is the average of the cube of Z(x) in the reference length, which is made dimensionless by the cube of the root mean square height (Zq), and is a value measured in accordance with JIS B 0601 (2013). The skewness Rsk is preferably -4 to -1.5. Here, from the viewpoint of regulating the structure of the front end portion of the concave-convex structure and reducing the dynamic frictional resistance, the skewness Rsk is preferably -4 or more, more preferably -3.8 or more, further preferably -3.6 or more, and on the other hand, is preferably -1.5 or less, more preferably -1.7 or less, further preferably -1.9 or less, and still further preferably -2.5 or less.

[0259] The kurtosis Rku is the average of the fourth power of Z(x) in the reference length, which is made dimensionless by the fourth power of the root mean square height (Zq), and is a value measured in accordance with JIS B 0601 (2013). The kurtosis Rku is preferably 5 to 20. Here, from the viewpoint of regulating the sharpness of the front end portion of the concave-convex structure and reducing the dynamic frictional resistance, the kurtosis Rku is preferably 5 or more, more preferably 6 or more, further preferably 7 or more, and still further preferably 11 or more, and on the other hand, is preferably 20 or less, more preferably 18 or less, and further preferably 16 or less.

[0260] As the shape of the concave-convex structure, the arithmetic average roughness Ra can be further considered. It is the average of the absolute value of Z(x) in the reference length, and is a value measured in accordance with JIS B 0601 (2013). The arithmetic average roughness Ra is preferably 0.01 μm or more, more preferably 0.02 μm or more, and further preferably 0.03 μm or more. On the other hand, from the viewpoint of ensuring the stability of the concave-convex structure, the arithmetic average roughness Ra is preferably 0.30 μm or less, more preferably 0.28 μm or less, and further preferably 0.26 μm or less.

[0261] The glass sheet of the second embodiment is obtained, for example, by employing a wet blasting method and setting the spray angle of the slurry to be within an appropriate range, the details of which are described later.

[0262] In addition, in the second embodiment, the element average length Rsm of the roughness curve, that is, the width of the concave-convex is large. In addition, the skewness Rsk is large in the negative direction, that is, the tip of the concave portion that is a valley is sharp, and the tip of the convex portion that is a hill is rounded. Furthermore, the kurtosis Rku is large, and the symmetry of the shape of the concave portion and the convex portion deviates from the normal distribution, and the tip of the convex portion is rounded. In this way, by deepening the cracks, that is, deepening the concave portion and the convex portion in the second embodiment, it is possible to maintain a low transmission haze, and achieve the desired average dynamic coefficient of friction COF and the friction variation amount delta. As a result, it is also possible to suppress the whiteness of the substrate, and it is possible to maintain the lightness L ＊ value low in the SCE method.

[0263] Anti-reflection film

[0264] In the second embodiment, the anti-reflection film is arbitrary.

[0265] For example, when an anti-reflection film that is the same as the absorption type anti-reflection film in the first embodiment is formed so as to cover at least a part of the concave-convex structure, it is possible to suppress the whiteness of the substrate and further reduce the lightness L ＊ value as in the first embodiment. The preferred form of the anti-reflection film at this time is the same as that of the absorption type anti-reflection film in the first embodiment.

[0266] In addition to the above, in the second embodiment, since the transmission haze is less than 15%, in addition to the anti-reflection film in the first embodiment, other anti-reflection films that have been widely used in the past can also be used.

[0267] For example, for an anti-reflection film of a laminated structure in which a low refractive index layer and a high refractive index layer are alternately laminated two or more layers, the main component of the high refractive index layer is preferably selected from at least one of silicon nitride, titanium oxide, niobium oxide, tantalum oxide, and zirconium oxide.

[0268] The more the number of laminations of the above-described laminated structure, the more it is possible to perform optical design of a layer configuration that exhibits lower reflectivity in a wider wavelength range. For example, the number of laminations in the laminated structure of the above-described anti-reflection film is preferably 2 to 8 layers in total, and more preferably 2 to 6 layers from the viewpoints of reflectivity reduction effect and mass productivity.

[0269] The materials of the high refractive index layer and the low refractive index layer are each not particularly limited, and can be appropriately selected in consideration of the degree of anti-reflectivity required, productivity, and the like, and the main component of the high refractive index layer is, for example, preferably selected from at least one of silicon nitride, titanium oxide, niobium oxide, tantalum oxide, and zirconium oxide as described above, and more preferably selected from at least one of silicon nitride, niobium oxide, and tantalum oxide from the viewpoints of productivity and refractive index.

[0270] As the material constituting the low refractive index layer, at least one selected from the group consisting of a silicon oxide, a mixed oxide containing Si and Sn, a mixed oxide containing Si and Zr, and a mixed oxide containing Si and Al is preferable, and a layer composed of a silicon oxide is more preferable from the viewpoints of productivity and refractive index.

[0271] Further, the preferable ranges of the light reflectance measured at the outermost surface on the first main surface side of the glass sheet having the antireflection film and the sheet resistance of the antireflection film are the same as the preferable ranges of the light reflectance and the sheet resistance in the first embodiment, respectively.

[0272] The preferable ranges of the light transmittance and b ＊ value

[0273] The preferable ranges of the light transmittance and b ＊ value measured at the outermost surface on the first main surface side of the glass sheet of the second embodiment are the same as the preferable ranges of the light transmittance and b ＊ value measured at the outermost surface on the first main surface side of the glass sheet of the first embodiment, respectively.

[0274] 〈Composition of Glass Sheet〉

[0275] The refractive index of the parent glass of the glass sheet of the present embodiment is preferably 1.4 to 1.7 from the viewpoint of sufficiently suppressing reflection in the bonding surface at the time of optical bonding of a display, a touch panel, or the like.

[0276] Specifically, a glass of various compositions can be used, and for example, an alkali-free glass, a soda-lime glass, a soda-lime silicate glass, an alumino-silicate glass, a borate glass, a lithium-alumino-silicate glass, a lead glass, an alkali-barium glass, an alumino-boro-silicate glass, a boro-silicate glass, or the like can be used. Among them, a soda-lime glass and an alumino-silicate glass are more preferable from the viewpoint that ion exchange in the chemical strengthening treatment described later can be easily performed.

[0277] Further, the glass composition preferably contains sodium, and a composition that can be subjected to strengthening in the forming and chemical strengthening treatment is preferable.

[0278] As a more specific glass composition, a glass containing, for example, 50 to 80% of SiO2, 0.1 to 25% of Al2O3, 3 to 30% of Li2O + Na2O + K2O, 0 to 25% of MgO, 0 to 25% of CaO, and 0 to 5% of ZrO2, expressed in terms of mol% on an oxide basis, can be given, but is not particularly limited.

[0279] Further, specifically, the following (i) to (v) can be given as the glass composition. Note that, for example, "containing 0 to 25% of MgO" means that MgO is not essential but can be contained up to 25%.

[0280] (i) a glass containing, in terms of mol% on an oxide basis, 63 to 73% of SiO2, 0.1 to 5.2% of Al2O3, 10 to 16% of Na2O, 0 to 1.5% of K2O, 0 to 5.0% of Li2O, 5 to 13% of MgO, and 4 to 10% of CaO,

[0281] (ii) a glass containing, in terms of mol% on an oxide basis, 50 to 74% of SiO2, 1 to 10% of Al2O3, 6 to 14% of Na2O, 3 to 11% of K2O, 0 to 5.0% of Li2O, 2 to 15% of MgO, 0 to 6% of CaO, and 0 to 5% of ZrO2, the total content of SiO2and Al2O3being 75% or less, the total content of Na2O and K2O being 12 to 25%, and the total content of MgO and CaO being 7 to 15%,

[0282] (iii) a glass containing, in terms of mol% on an oxide basis, 68 to 80% of SiO2, 4 to 10% of Al2O3, 5 to 15% of Na2O, 0 to 1% of K2O, 0 to 5.0% of Li2O, 4 to 15% of MgO, and 0 to 1% of ZrO2,

[0283] (iv) a glass containing, in terms of mol% on an oxide basis, 67 to 75% of SiO2, 0 to 4% of Al2O3, 7 to 15% of Na2O, 1 to 9% of K2O, 0 to 5.0% of Li2O, 6 to 14% of MgO, and 0 to 1.5% of ZrO2, the total content of SiO2and Al2O3being 71 to 75%, the total content of Na2O and K2O being 12 to 20%, and the content of CaO being less than 1% when CaO is contained,

[0284] (v) a glass containing, in terms of mol% on an oxide basis, 56 to 73% of SiO2, 7 to 24% of Al2O3, 0 to 6% of B2O3, 0 to 6% of P2O5, 2 to 12% of Li2O, 2 to 11% of Na2O, 0 to 5% of K2O, 0 to 8% of MgO, 0 to 2% of CaO, 0 to 5% of SrO, 0 to 5% of BaO, 0 to 5% of ZnO, 0 to 2% of TiO2, and 0 to 4% of ZrO2.

[0285] (vi) a glass containing, in terms of mole% on an oxide basis, 58 to 80% of Si02, 13 to 18% of Al203, 0 to 5% of B203, 0.5 to 4% of P205, 3 to 10% of Li20, 5 to 20% of Na20, 0 to 2% of K20, 0 to 11% of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 15% of BaO, 0 to 10% of ZnO, 0 to 1% of Ti02, 0 to 2% of Zr02.

[0286] 〈Chemical strengthening treatment〉

[0287] From the viewpoint of improving strength and preventing breakage when stress is applied from the outside, the glass sheet of the present embodiment preferably has a compressive stress layer introduced to the surface of the glass sheet, and more preferably is a chemically strengthened glass sheet that has been subjected to chemical strengthening treatment by ion exchange treatment.

[0288] In the case where the glass sheet is subjected to chemical strengthening treatment, the total content of Li20 and Na20 in the glass composition is preferably 12 mole% or more in order to properly perform the chemical strengthening treatment.

[0289] Further, in order to increase the surface compressive stress (CS) and the depth of layer (DOL) of the compressive stress layer, the glass composition of the glass sheet preferably contains 60 mole% or more of Si02and 8 mole% or more of Al203.

[0290] 〈Anti-fouling film〉

[0291] The glass sheet of the present embodiment can further have an anti-fouling (AFP) film on the above-described anti-reflection film or in a manner of covering the above-described concavo-convex structure formed on the first main surface.

[0292] The anti-fouling film is a film that suppresses the adhesion of organic matter and inorganic matter on the surface, or is a film that brings about an effect of easily removing adhered matter by cleaning such as wiping even in a case where organic matter and inorganic matter are adhered to the surface.

[0293] The anti-fouling film is not particularly limited as long as it imparts anti-fouling properties, and although not particularly limited, preferably contains a fluorine-containing compound, and for example, a fluorine-containing silicone compound film obtained by curing a fluorine-containing silicone compound through a hydrolysis condensation reaction can be cited.

[0294] The fluorine-containing organosilicon compound is not particularly limited as long as it imparts stain repellency, water repellency, and oil repellency. For example, a fluorine-containing organosilicon compound having one or more groups selected from the group consisting of a polyfluoro polyether group, a polyfluoro alkylene group, and a polyfluoro alkyl group can be mentioned. Note that the polyfluoro polyether group refers to a divalent group having a structure in which a polyfluoro alkylene group and an etheric oxygen atom are alternately bonded.

[0295] In addition, as the fluorine-containing organosilicon compound commercially available, for example, KP-801 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY178 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-130 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-185 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), OPTOOL (registered trademark) DSX, and OPTOOL AES (both trade names, manufactured by Daikin Industries, Ltd.) can be mentioned.

[0296] The thickness of the stain repellent film is not particularly limited, but when the stain repellent film is composed of a fluorine-containing organosilicon compound coating, the thickness is preferably 2 to 20 nm. From the viewpoint of forming a uniform covering state by the stain repellent film and obtaining good scratch resistance, the thickness is preferably 2 nm or more. In addition, from the viewpoint of maintaining good optical properties, the thickness is preferably 20 nm or less, more preferably 15 nm or less, and further preferably 10 nm or less.

[0297] 〈Size, Shape〉

[0298] The thickness of the glass sheet of the present embodiment is not particularly limited, but in the case where chemical strengthening treatment is performed, it is generally preferable to be 5 mm or less from the viewpoint of efficiently performing the treatment. In addition, in addition to the above viewpoint, in the case where the glass sheet is used as a cover glass for a display device for a vehicle, the thickness of the glass sheet is more preferably 3 mm or less from the viewpoint of lightening the vehicle body, and in addition, from the viewpoint of strength, the thickness of the glass sheet is preferably 0.2 mm or more, more preferably 0.8 mm or more, and further preferably 1 mm or more.

[0299] The size of the glass of the present embodiment is also not particularly limited and can be appropriately determined depending on the use.

[0300] The glass sheet of the present embodiment can have a curved portion on at least one of the first main surface and the second main surface. The curved portion refers to a portion in which the average curvature is not zero. In this case, it is preferable that the glass sheet be shaped into a predetermined shape from a flat plate.

[0301] From the viewpoint of finger slidability when a person's finger touches the curved portion, the dynamic friction coefficient of the curved portion is preferably 0.02 or less, more preferably 0.015 or less, and further preferably 0.01 or less.

[0302] Note that the dynamic friction coefficient of the curved portion in the present specification is a value obtained by the same method as the average dynamic friction coefficient COF of the surface of the region having the concavo-convex structure of the glass sheet.

[0303] <Second main surface>

[0304] The glass sheet of the present embodiment can have a printed layer on at least a part of the second main surface. In the case where the glass sheet is used for a cover glass of a display device, by providing the printed layer, an effect of improving operability by indicating the position of a button to a user, and an effect of improving designability by hiding a wiring for a touch panel are obtained.

[0305] The printed layer is preferably provided on at least a part of the second main surface, and is provided using a publicly known method and conditions.

[0306] In addition to the above, the glass sheet of the present embodiment can have other functional layers provided on at least one of the first main surface and the second main surface within a range not impairing the effects of the present application. As the other functional layers, for example, an infrared ray cut layer, an ultraviolet ray cut layer, a water repellent layer, an antistatic layer, a primer layer, an adhesion improving layer, a protective layer, and the like can be given. These other functional layers can be provided using a publicly known method and a publicly known substance.

[0307] <Display device for vehicle>

[0308] The use of the glass sheet of the present embodiment is not particularly limited, and for example, the glass sheet can be used for a cover glass of a display (notebook, monitor, LCD, PDP, ELD, CRT, PDA, and the like).

[0309] Among them, since it can also be well used for a use in which the distance of a person visually recognizing the glass sheet from the glass sheet is fixed, and a touch when operating a touch panel is required, it is preferable to be used for a cover glass of a display device for a vehicle.

[0310] The display device for a vehicle can be, for example, an instrument panel of a cluster called an instrument cluster, a car navigation device, a CID (Center Information Display) that displays audio, an RSE (Rear Seat Entertainment), and the like.

[0311] That is, the present application also relates to a display device for a vehicle provided with a cover glass composed of the above glass sheet and a display panel. The display panel is provided with a light emitting body, and as the light emitting body, for example, an organic EL, an OLED (Organic Light Emitting Diode), a light source for a liquid crystal display (LCD), a micro LED, a phosphor, and the like can be given. That is, as the display device, an organic EL display, an OLED display, an LCD, a micro LED display, a plasma display, and the like can be given.

[0312] The glass sheet in the display device for vehicle is configured so that the first major surface side of the glass sheet becomes the visually recognized side. The display device for vehicle of the present embodiment is excellent in both the visual recognition and the tactile sensation at the time of sliding operation in addition to the good visual recognition.

[0313] <Selection method>

[0314] The present application also relates to a method for selecting the glass sheet of the present embodiment described above when a glass sheet excellent in both the visual recognition and the tactile sensation at the time of sliding operation while maintaining appropriate visual recognition is obtained.

[0315] The glass sheet of the present embodiment described above refers to a glass sheet having a first major surface and a second major surface opposite to the first major surface, and the first major surface has a relief structure at least in part. The visual recognition index value T of the surface of the region having the relief structure on the first major surface side is 0.85 or greater, the glare index value S is 0.80 or greater, the average dynamic coefficient of friction COF is 0.50 or less, and the friction variation delta exceeds -0.210. In addition, the lightness L of the glass sheet is 4.7 or less. ＊

[0316] The preferable mode of the glass sheet in the selection method of the present embodiment is the same as that of the glass sheet described above.

[0317] <Manufacturing method of glass sheet>

[0318] The manufacturing method of the glass sheet of the present embodiment includes the following steps (i) and (ii).

[0319] (i) a step of preparing a glass sheet having a first major surface and a second major surface opposite to the first major surface,

[0320] (ii) a step of forming a relief structure on at least a part of the first major surface.

[0321] A step of strengthening the glass sheet can be further included as a step (iii) between the step (i) and the step (ii) or after the step (ii), and the step of strengthening is preferably performed after the step (ii).

[0322] In addition, a step of forming an antireflection film so as to cover at least a part of the relief structure can be further included as a step (iv). The step (iv) can be performed after the step (ii), but in the case where the strengthening treatment of the step (iii) is performed, the step (iv) is preferably performed after the step (iii).

[0323] <Step (i): Step of preparing glass sheet>

[0324] The glass sheet of the step (i) can be used as a commercially available glass sheet or can be manufactured.​

[0325] In the case of manufacturing a glass sheet, a conventionally known method can be employed.

[0326] For example, raw materials of respective components are prepared in such a manner as to become a desired composition, and are subjected to heating and melting in a glass melting furnace. The glass is homogenized by bubbling, stirring, addition of a fining agent, or the like, and is formed into a glass sheet of a prescribed thickness by a conventionally known forming method, and is subjected to slow cooling.

[0327] The forming method of the glass can be, for example, a float method, a press method, a fusion method, a down-draw method, and a roll press method. Among these, in the case of mass production, the float method is preferred. In addition, as a continuous forming method other than the float method, the fusion method and the down-draw method are also preferred.

[0328] The glass member formed into a flat plate shape by an arbitrary forming method is cut into a desired size after slow cooling. Note that, in the case where more accurate dimensional accuracy or the like is required, the glass member after cutting can be subjected to polishing processing or end face processing described later. Thereby, in the operation of the forming step or the like, breakage or defects of the glass sheet can be reduced, and the yield can be improved.

[0329] In the case where a curved portion is provided in at least either of the first main face and the second main face of the glass sheet, the glass sheet in a flat plate shape can be formed into a prescribed shape.

[0330] The forming can be performed while heating the glass, and the forming method can use, for example, a self-weight forming method, a vacuum forming method, a press forming method, or the like.

[0331] Note that the forming of the glass can be performed before the step (ii), or after the step (ii). In particular, in the case where the frosting method or the wet-type sand blasting method is performed in the step (ii), the forming of the glass is preferably performed after the step (ii).

[0332] In the case where the polishing processing is performed on at least one main face of the glass sheet, the polishing processing can be performed, for example, by moving a polishing processing portion of a rotary polishing tool at a constant speed while contacting the polishing processing portion at a constant pressure. By performing the polishing under the conditions of the constant pressure and the constant speed, the polishing can be uniformly performed on the polishing surface at a constant polishing rate.

[0333] The end face of the glass sheet can be subjected to end face processing such as chamfering processing.

[0334] The chamfering processing is preferably processing generally called R-chamfering or C-chamfering, which is performed by mechanical grinding, and can also be processing performed by etching or the like, and is not particularly limited.

[0335] <Step (ii): Step of forming concave-convex structure>

[0336] In the process (ii), at least a part of the first main surface is formed with the region having the uneven structure, either of chemical treatment and physical treatment can be employed.

[0337] As the method of chemical treatment, a method of providing the unevenness to the first main surface itself by a grinding method or the like can be given.

[0338] As the method of physical treatment, a method of forming the region having the uneven structure on the first main surface by a two-fluid spray method, an electrostatic spray method or the like can be given.

[0339] As the method of combining the physical treatment and the chemical treatment, a wet sand blasting method of performing etching after performing wet sand blasting processing or the like can be given.

[0340] In the present embodiment, the grinding method and the wet sand blasting method are particularly preferable.

[0341] • Grinding method

[0342] In a case where the uneven structure is formed by the grinding method, generally, the processes of pre-washing, cleaning, chemical liquid immersion and cleaning are performed in this order. The pre-washing and the two cleanings in the above can be performed by a conventionally known method.

[0343] In the chemical liquid immersion in the above, it is preferable to include a process of immersing the glass plate in a solution containing potassium fluoride (KF) and hydrogen fluoride (HF) and a process of subsequently immersing the glass plate in a solution containing hydrogen fluoride. Between the immersion in the two kinds of solutions, cleaning and drying can be appropriately performed.

[0344] The grinding processing is performed by the process of immersing in the solution containing potassium fluoride and hydrogen fluoride, and the uneven structure is formed on the surface of the glass plate. Subsequently, the etching is performed by the process of immersing the glass plate in the solution containing hydrogen fluoride, and the transmission haze of the surface of the glass plate is adjusted.

[0345] The solution used for the grinding processing uses a mixed solution containing potassium fluoride and hydrogen fluoride, and the concentration of the potassium fluoride in the mixed solution is preferably 0.5 to 5.0 mass%. Here, from the viewpoint of sufficiently performing the grinding processing, the above concentration is preferably 0.5 mass% or more, more preferably 0.7 mass% or more, and further preferably 1.0 mass% or more. In addition, from the viewpoint of not excessively refining the surface structure of the glass plate, moderately roughening the surface structure, and securing the appearance quality, the above concentration is preferably 5.0 mass% or less, more preferably 4.5 mass% or less, and further preferably 4.0 mass% or less.

[0346] The concentration of hydrogen fluoride in the mixed solution is preferably 0.5 to 4.0 mass%. Here, from the viewpoint of sufficiently etching the substrate in the frosted processing, the concentration is preferably 0.5 mass% or more, more preferably 0.7 mass% or more, and further preferably 1.0 mass% or more. In addition, from the viewpoint of not excessively etching and peeling off the masking component generated on the surface of the substrate, the concentration is preferably 4.0 mass% or less, more preferably 3.5 mass% or less, and further preferably 3.0 mass% or less.

[0347] In addition, in the mixed solution, the ratio of the concentration of potassium fluoride to the concentration of hydrogen fluoride (KF / HF) is preferably 0.33 to 3.0. Here, from the viewpoint of precipitating and fixing the masking component on the surface of the substrate, the ratio is preferably 0.33 or more, more preferably 0.5 or more, and further preferably 0.75 or more. In addition, from the viewpoint of not excessively refining the surface structure of the glass plate, moderately roughening the surface structure, and ensuring the appearance quality, the ratio is preferably 3.0 or less, more preferably 2.0 or less, and further preferably 1.33 or less.

[0348] The mixed solution can further contain other compounds, in which case, for example, a fluoride, such as ammonium fluoride, potassium phosphate, or the like, is preferable. The concentration of the other compounds is preferably 15 mass% or less.

[0349] Note that the mixed solution is an aqueous solution.

[0350] The temperature at which the glass plate is immersed in the solution used in the frosted processing is preferably 10 to 50°C, and more preferably 15 to 40°C. In addition, the time of immersion is preferably 60 to 360 seconds, and more preferably 120 to 240 seconds.

[0351] The solution used in the etching processing uses a solution containing hydrogen fluoride, and the concentration of hydrogen fluoride in the solution is preferably 0.5 to 20 mass%. Here, from the viewpoint of uniformly and efficiently obtaining a proper shape of the leading end of the concave-convex structure formed by the frosted processing, the concentration is preferably 0.5 mass% or more, more preferably 1.0 mass% or more, and further preferably 2.0 mass% or more. In addition, in order to prevent the formation of a coating on the surface of the substrate due to the bonding of ions generated when the substrate is melted with fluorine ions, the concentration is preferably 20 mass% or less, more preferably 17 mass% or less, and further preferably 15 mass% or less.

[0352] The solution can further contain other compounds, in which, from the viewpoint of preventing the melting of the crystal generated on the surface of the substrate due to the bonding of ions generated when the substrate is melted with fluorine ions, a mixed solution with other acids is preferable. As the other acids, hydrochloric acid, nitric acid, sulfuric acid, and the like are preferable.

[0353] In the case of a mixed solution with other acids, the ratio of the concentration of hydrogen fluoride to the total concentration of the other acids is preferably 0.3 to 3.0, more preferably 0.5 or more, and still more preferably 2.0 or less.

[0354] Note that the above solution is an aqueous solution.

[0355] The post-etching amount of the etching processing is not particularly limited, but is preferably, for example, 0.5 to 15 μm. Here, from the viewpoint of sufficiently removing contaminant components adhering to the surface of the substrate, the post-etching amount is preferably 0.5 μm or more, and more preferably 1.0 μm or more. In addition, from the viewpoint of not significantly changing the thickness of the substrate, the post-etching amount is preferably 15 μm or less, more preferably 10 μm or less, and still more preferably 7.0 μm or less.

[0356] By using the frosting method as described above, a glass sheet can be obtained in which the most surface of the area having the concavo-convex structure maintains the visual recognition index value T of 0.85 or more and the glare index value S of 0.80 or more, and also achieves the average dynamic friction coefficient COF of 0.50 or less and the friction variation amount delta exceeding -0.210.

[0357] In addition, by using the frosting method as described above, a glass sheet can be obtained in which, with respect to the surface roughness of the above most surface, the element average length Rsm of the roughness curve is less than 26 μm, the arithmetic average roughness Ra is 0.12 μm or more, the skewness Rsk is -1 to 1, and the kurtosis Rku is 2 to 4.

[0358] The most surface of the area having the concavo-convex structure of the above obtained glass sheet has a transmission haze of 15% or more, but by forming an absorption-type anti-reflection film in a manner of covering the concavo-convex structure, the whiteness of the substrate can be suppressed, and the lightness L ＊ value is set to 4.7 or less.

[0359] • Wet sand blasting method

[0360] In the case of forming the concavo-convex structure by the wet sand blasting method, generally, a glass sheet, preferably a glass sheet that has been subjected to polishing processing, is subjected to wet sand blasting processing, followed by processes such as cleaning, etching treatment, and cleaning.

[0361] In the wet sand blasting processing in the above, it is preferable to include a process of jetting slurry to the first main surface of the glass sheet to perform roughening, and a process of immersing the glass sheet in a solution containing hydrogen fluoride to perform etching. Between the process of performing roughening and the process of performing etching, cleaning and drying can be appropriately performed.

[0362] In the roughening process, a slurry of a liquid such as water and particles (abrasive grains) as an abrasive material is delivered to a spray gun by a pump, accelerated by compressed air, and then sprayed to the first main surface of the glass sheet, thereby performing surface roughening or processing, cleaning, shot blasting, or the like.

[0363] By appropriately changing the abrasive grain particle diameter, abrasive grain distribution, abrasive grain type, abrasive grain concentration, spray pressure, spray time, scanning speed, scanning number, scanning pitch, spray angle, spray distance, or the like of the particles (abrasive grains) used in the roughening process, preferred conditions for maintaining optical properties for proper visual recognition and achieving good tactile sensation are determined.

[0364] It is found in the above conditions that, in particular, by making the spray angle of the slurry flatter than ever, the generation of lateral cracks can be suppressed, and central cracks are dominant.

[0365] By making central cracks dominant, when etching processing is subsequently performed, a concave-convex structure with a large aspect ratio can be formed, and a glass sheet with a small average dynamic friction coefficient COF and a small lightness L ＊ value can be obtained.

[0366] From the above viewpoint, the spray angle of the slurry with respect to the first main surface is preferably less than 90°, more preferably 70° or less, and further preferably 65° or less. In addition, from the viewpoint of sufficiently introducing cracks, the above spray angle is preferably 45° or more, and more preferably 50° or more.

[0367] It is found that, in addition to or on the basis of the above spray angle, conditions such as the abrasive grain particle diameter and the spray pressure are also very effective in suppressing the generation of lateral cracks.

[0368] The abrasive grain type can use a substance known in the art, and for example, alumina, silicon carbide can be cited.

[0369] The abrasive grain particle diameter differs depending on the abrasive grain type, and for example, in the case of using alumina, the average particle diameter according to JIS R 6001 (1987) is preferably #1500 or less (a larger number of particle sizes), and more preferably #2000 or less (a larger number of particle sizes). The lower limit of the particle size is not particularly limited, but the above particle size is preferably #6000 or more.

[0370] The spray pressure is preferably 0.1 to 0.6 MPa. Here, from the viewpoint of introducing cracks sufficiently deep into the surface of the substrate, the spray pressure is preferably 0.1 MPa or more, more preferably 0.15 MPa or more, and further preferably 2.0 MPa or more. In addition, from the viewpoint of preventing edge collapse or damage to the discharge portion, the spray pressure is preferably 0.6 MPa or less, more preferably 0.5 MPa or less, and further preferably 0.4 MPa or less.

[0371] The abrasive particle concentration is preferably 5 to 20% by volume. Here, from the viewpoint of introducing a sufficient amount of cracks into the surface of the substrate, the abrasive particle concentration is preferably 5% by volume or more, more preferably 7% by volume or more, and further preferably 10% by volume or more. In addition, from the viewpoint of sufficiently dispersing the abrasive particles in the liquid, the abrasive particle concentration is preferably 20% by volume or less, more preferably 17% by volume or less, and further preferably 15% by volume or less.

[0372] The number of scans is preferably 2 to 64. Here, from the viewpoint of eliminating unevenness in the scan of wet blasting, the number of scans is preferably 2 or more, more preferably 4 or more, and further preferably 8 or more. In addition, from the viewpoint of controlling the processing time to a practical range, the number of scans is preferably 64 or less, more preferably 48 or less, and further preferably 32 or less.

[0373] In the process of performing etching, a solution containing hydrogen fluoride is used, and the concentration of hydrogen fluoride in the solution is preferably 0.5 to 20% by mass. Here, from the viewpoint of amplifying the cracks introduced by wet blasting processing and obtaining an appropriate shape, the concentration is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and further preferably 1.5% by mass or more. In addition, from the viewpoint of preventing the formation of crystals that are difficult to etch due to the bonding of ions generated when the substrate melts at the front end of the cracks and fluoride ions, which hinders etching and changes the shape of the cracks, the concentration is preferably 20% by mass or less, more preferably 17% by mass or less, and further preferably 15% by mass or less.

[0374] The above solution can further contain other compounds, in which case, for example, hydrochloric acid, sulfuric acid, and the like can be given. The concentration of the other compounds is preferably 15% by mass or less.

[0375] Note that the above solution is an aqueous solution.

[0376] The etching amount in the process of performing etching is not generally specified, but is preferably, for example, 1.0 to 30 μm, and more preferably 2.0 to 20 μm.

[0377] By using the wet blasting method as described above, a glass sheet having excellent optical properties in which the visual recognition index value T is 0.85 or more, the glare index value S is 0.80 or more, and the lightness L value is 4.7 or less on the surface of the region having the concavo-convex structure, and also having excellent tactile sensation during sliding in which the average dynamic friction coefficient COF is 0.50 or less and the friction variation amount delta exceeds -0.210 can be obtained. ＊

[0378] ​Further, by using the wet blasting method as described above, a glass sheet can be obtained in which the element average length Rsm of the roughness curve is 26 μm or more, the skewness Rsk is -4 to -1.5, and the kurtosis Rku is 5 to 20 with respect to the surface roughness of the uppermost surface.

[0379] Further, in the case where the concavo-convex structure is formed by the wet blasting method, for example, by setting the spray angle of the slurry to 70° or less with respect to the first main surface, it is possible to set the transmission haze to 15% or less while achieving good optical properties and tactile sensation as described above.

[0380] On the other hand, even if the wet blasting method is used, in the case where the transmission haze of the uppermost surface of the region having the concavo-convex structure exceeds 15%, as in the case where the concavo-convex structure is formed by the grinding method, by forming the above-described absorption-type anti-reflection film in a manner to cover the concavo-convex structure, it is possible to suppress the whiteness of the substrate and set the lightness L ＊ value to 4.7 or less.

[0381] <Process (iii): Process of performing strengthening treatment>

[0382] In the case where the glass sheet is subjected to the process (iii) as the strengthening treatment, the process (iii) can be performed between the above-described processes (i) and (ii), but is preferably performed after the process (ii).

[0383] The glass sheet is subjected to the strengthening treatment on at least either of the first main surface and the second main surface, and a compressive stress layer is formed on the surface, and the strength and the scratch resistance are improved.

[0384] The strengthening treatment can apply any one of a physical strengthening treatment and a chemical strengthening treatment, and a larger compressive stress can be introduced even in a glass sheet having a small thickness, and thus the chemical strengthening treatment is preferred.

[0385] In the chemical strengthening treatment, alkali metal ions having a small ionic radius existing on the surface of the glass sheet are exchanged for alkali metal ions having a large ionic radius by immersing the glass sheet in a molten alkali metal salt at a temperature below the glass transition temperature. Specifically, Li ions on the surface of the glass sheet are exchanged for Na ions, or Na ions on the surface of the glass sheet are exchanged for K ions. Thereby, a compressive stress layer can be formed on the surface of the glass sheet.

[0386] The molten salt and the treatment conditions used in the chemical strengthening treatment can use the molten salt and the treatment conditions conventionally known.

[0387] <Process (iv): Process of forming anti-reflection film>

[0388] In the process (iv), an antireflection film is formed on the glass sheet on which the concavo-convex structure is formed on the surface, or the glass sheet on which the concavo-convex structure is formed on the surface and further subjected to chemical strengthening treatment.

[0389] In forming the antireflection film, it is only necessary to form in a manner to cover at least a part of the concavo-convex structure, and it is preferable to form in a manner to cover the area of the glass sheet which is visually recognized and touched by sliding action or the like.

[0390] Even in the case where the transmission haze of the surface of the area of the glass sheet having the concavo-convex structure is high, by forming the above-described absorption type antireflection film described in the first embodiment of the above-described 〈First Embodiment·Second Embodiment〉, the brightness L ＊ value can be reduced, and good visual recognition can be achieved.

[0391] The antireflection film can be formed by a publicly known method. For example, a publicly known film forming method such as sputtering method, vacuum evaporation method, coating method, chemical vapor deposition method (CVD method), physical vapor deposition method (PVD method) such as PLD method is used, and a dielectric layer or layers are sequentially formed and laminated on the surface of the first principal surface of the glass sheet, whereby the antireflection film is obtained. In addition, the antireflection film can also be formed on the surface of the second principal surface of the glass sheet.

[0392] As the sputtering method, there are, for example, magnetron sputtering, pulse sputtering, AC sputtering, digital sputtering, and the like.

[0393] Among the above, for example, the magnetron sputtering method is a method in which a magnetic field is generated by providing a magnet on the back surface of a material which is a mother body of a dielectric layer or layers, and gas ion atoms collide with the surface of the material to be sputtered, thereby performing sputtering film formation in a thickness of several nm. A continuous film of a dielectric of an oxide or nitride of the material can be formed.

[0394] Among the above, for example, the digital sputtering method is a method in which, after forming an ultrathin film of a metal by sputtering, oxidation is performed by irradiating oxygen plasma, oxygen ions, or oxygen radicals, and the above-described process is repeated in the same chamber, thereby forming a thin film of a metal oxide. In this case, the film forming molecule is a metal at the time of being coated on the substrate, and thus it is presumed to have ductility compared to the case of being coated with a metal oxide. Therefore, it is considered that rearrangement of the film forming molecule is easily caused even at the same energy, and as a result, a dense and smooth film is formed.

[0395] In the coating method, for example, after coating a precursor composition which constitutes a layer of the antireflection film by a spin coating method, dip coating method, casting method, slit coating method, spray coating method, electrostatic spray deposition method (ESD method), or the like, heat treatment is performed as necessary, and the above-described method is repeated, whereby a laminated structure can be formed.

[0396] In addition to the above-mentioned processes (i) to (iv), in the case where an antifouling film (AFP film) is further formed, a publicly known method can be employed. For example, a method in which a composition of a silane coupling agent having a fluoroalkyl group such as a perfluoroalkyl group, a fluoroalkyl group containing a perfluoro(polyoxyalkylene) chain, or the like is coated by a spin coating method, a dip coating method, a casting method, a slit coating method, a spray coating method, or the like, and then heat treatment is performed as necessary, or a vacuum evaporation method in which a fluorine-containing organosilicon compound is vapor-deposited on the surface of the close-contact layer, and then heat treatment is performed as necessary, or the like can be mentioned.

[0397] The composition that becomes the precursor of the antifouling film is not particularly limited as long as it is a composition containing a fluorine-containing hydrolyzable silicon compound and is capable of forming a film. The above-mentioned composition can contain any component other than the fluorine-containing hydrolyzable silicon compound.

[0398] The above-mentioned any component is not particularly limited as long as it does not hinder the effects of the present application, and for example, a hydrolyzable silicon compound not having a fluorine atom (hereinafter referred to as "non-fluorine hydrolyzable silicon compound"), a catalyst, or the like can be mentioned.

[0399] Example

[0400] Hereinafter, the present application will be described in detail with reference to examples. However, the present application is not limited by the following description.

[0401] Examples 1 to 6 and 10 are examples, and Examples 7 to 9 and 11 to 16 are comparative examples.

[0402] < Evaluation Method >

[0403] The following evaluations were measured for each example. As the respective physical property values, measurement was performed at any 3 points on the diagonal line of the glass plate, and the average value thereof was used.

[0404] < Average Dynamic Friction Coefficient COF, Friction Change Amount Delta >

[0405] In a static and dynamic friction measuring machine (manufactured by Trinity-Lab Co., multifunctional static and dynamic friction measuring machine TL201), the dynamic friction coefficient was measured by sliding a simulated finger at a scan distance of 50 mm, a load of 100 g, and a scan speed of 100 mm / sec on the surface of the region having a concave-convex structure on the first main surface side of the glass plate in an environment of room temperature 23°C and humidity 21%. The data acquisition frequency was 1 kHz, and the number of samples was 5.

[0406] The simulated finger was made of polyurethane (manufactured by Trinity-Lab Co., polyurethane simulated finger), and the contact portion with the surface of the glass plate was formed with linear convex portions at 0.5 mm intervals in a direction at right angles to the sliding direction in an area of 10 x 15 mm.

[0407] Here, the time when the kinetic friction coefficient first becomes 0 or less is set as the motion start time, and the time after {(motion start time) + (0.75 x scan distance / scan speed)} is set as the motion end time. Further, a value calculated by the following equation (3) is set as the average kinetic friction coefficient COF, and a value calculated by the following equation (4) is set as the friction variation delta.

[0408] Average kinetic friction coefficient COF = average value of kinetic friction coefficient at (time halfway between motion start time and motion end time) ± 0.2 seconds Equation (3)

[0409] Friction variation delta = (maximum kinetic friction coefficient after motion end time) - (average kinetic friction coefficient COF) Equation (4)

[0410] <Visual discriminability index value T>

[0411] A glass plate (100 mm x 100 mm x 1.3 mm t) was disposed with the first main surface side as the light source side at a position 30 mm above a slit-shaped white light source having a length of 40 mm and a width of 0.1 mm. Then, the luminance of the surface of each region having a concave-convex structure was measured using an SMS-1000 (analysis device) manufactured by DM & S Co. (Display-Messtechnik & Systeme Co.) to detect the light transmitted through the glass plate and the angle θ from the second main surface side of the glass plate.

[0412] A C1614A lens having a focal length of 16 mm was used with an aperture of 5.6, and the distance from the surface of the glass plate to the lens was set to 550 mm.

[0413] When the direction parallel to the thickness direction of the glass plate was set as the angle θ = 0°, the average value of the luminance in the range of the angle θ = 0° ± 0.1° was set as Tl, the average value of the luminance in the range of the angle θ = 0.7° ± 0.1° was set as T2, and the average value of the luminance in the range of the angle θ = -0.7° ± 0.1° was set as T3, a value calculated by the following equation (1) was set as the visual discriminability index value T.

[0414] Visual discriminability index value T = 1 - (T2 + T3) / (2 x Tl) Equation (1)

[0415] <Glare index value S>

[0416] A glass plate (100 mm x 100 mm x 1.6 mmt) was disposed with the second major face side of the display device (iPad-Air (registered trademark), manufactured by Apple Inc.) abutting. In a state in which the display device displayed an image of a green monochrome color composed of RGB (0, 255, 0), the Sparkle value of the surface of the region having the uneven structure, which was calculated by image analysis using SMS-1000 manufactured by DM&S Co., Ltd., disposed on the first major face side of the glass plate, was set as the glare S a .

[0417] The distance d between SMS-1000 manufactured by DM&S Co., Ltd. and the surface of the first major face side of the glass plate was 540 mm, and a 23 FM50SP lens having a focal length of 50 mm was used with an aperture of 5.6.

[0418] Image analysis was performed under the same conditions for a glass substrate (VRD140 glass; manufactured by AGC Glass Europe Co., Ltd.) of the same size (100 mm x 100 mm x 1.6 mmt) as the reference sample, and the calculated Sparkle value was set as the glare S s .

[0419] The value calculated from the value of S a and the value of S s by the following formula (2) was set as the glare index value S.

[0420] Glare index value S = 1 - (S a / S s ) Formula (2)

[0421] 〈Reflection image diffusivity index value R〉

[0422] A glass plate (100 mm x 100 mm x 1.3 mmt) was disposed with the first major face side facing upward, and the brightness of the reflected light obtained by irradiating a slit-shaped light having a width of 101 mm from above the glass plate was measured using SMS-1000 manufactured by DM&S Co., Ltd. At this time, in order to eliminate the reflected light from the second major face side (back surface reflection), a black plate that extinguishes light was disposed on the second major face side. The camera lens used was a C1614A lens having a focal length of 16 mm with an aperture of 5.6, the distance from the surface of the first major face of the glass plate to the camera lens was set to 300 mm, and the Imaging Scale was set to a range of 0.0276 to 0.0278.

[0423] When the direction parallel to the thickness direction of the glass plate is set as the angle φ = 0°, light is irradiated from an angle of φ = 5.7° ± 0.1°, and the angle φ = -5.7° during total internal reflection is taken as the reference (angle α = 0°). The average brightness of the reflected light in the range of angle α = 0° ± 0.1° is set as R1, the average brightness of the reflected light in the range of angle α = 0.5° ± 0.1° is set as R2, and the average brightness of the reflected light in the range of angle α = -0.5° ± 0.1° is set as R3. The value calculated by the following formula (5) is set as the reflective image diffusion index value R.

[0424] The reflectance image diffusion index value R = (R2 + R3) / (2 × R1) Equation (5)

[0425] <Brightness L ＊ value>

[0426] As an evaluation of the whiteness of the glass plate, the lightness L under the excluded specular reflection (SCE) method was measured using a CM-26d manufactured by Konica Minolta Corporation, according to the method of ASTM E313-73. ＊ value.

[0427] Specifically, the measuring port of the measuring machine is brought into contact with a glass plate to prevent external light from entering, allowing light from a specified light source to strike the glass plate. A photodetector is used to detect the spectrum of the reflected light from the glass plate, and L is calculated from the obtained spectrum. ＊ a ＊ b ＊ Color system, from which lightness L is obtained ＊ value.

[0428] Surface roughness

[0429] On the outermost surface of the region with an uneven structure in the glass plate, the element mean length Rsm, arithmetic mean roughness Ra, skewness Rsk, kurtosis Rku and maximum cross-sectional height Rt of the roughness curve, which are indicators of surface roughness, were measured according to JIS B 0601 (2013).

[0430] Specifically, using a Keyence Corporation VK-X3000 with a 50x objective lens, a 280μm × 200μm field of view was captured on the substrate after the formation of the uneven structure and before the formation of the anti-reflective coating. The resulting image was obtained by applying a plane tilt correction to the entire image without using a cutoff value.

[0431] For the image, 21 straight lines of the total width of the image in the horizontal direction of the Y axis at 10 μm intervals of the image were defined, and 21 Rsm, Ra, Rsk, Rku, Rt were calculated from the cross-sectional profiles thereof, respectively, and the average value thereof was set as the value of Rsm, Ra, Rsk, Rku, Rt of the surface of the glass sheet. As described above, the measurement was performed on any 3 places on the diagonal line of the glass sheet by the same operation, and the average value thereof was set as the value of Rsm, Ra, Rsk, Rku, Rt. Note that the measurement was performed before the formation of the antireflection film, but since the antireflection film is formed along the unevenness of the glass sheet, it does not greatly affect each parameter of the surface roughness, and thus it can be regarded as the value measured after the formation of the antireflection film.

[0432] 〈Transmission haze〉

[0433] The transmission haze of the surface of the region of the glass sheet having the antireflection film covering the uneven structure was measured by the method according to JIS K7136 (2000).

[0434] Specifically, the light source was disposed on the first main surface side of the glass sheet as the light source side, and the transmission light was measured from above the glass sheet using a haze meter HZ-1 manufactured by SUGA Test Machine Co., Ltd.

[0435] When the direction parallel to the thickness direction of the glass sheet was set as the angle of 0°, the light detected within ±2.5° was regarded as the transmission light, and the light detected in the range of less than -2.5° or more than +2.5° was regarded as the scattered light (transmission light loss). Then, the proportion of the above-mentioned scattered light with respect to the sum of the above-mentioned transmission light and the scattered light, i.e., the total light transmittance was set as the transmission haze (%).

[0436] 〈Surface light transmittance〉

[0437] The surface light transmittance measured on the surface of the first main surface side of the region of the glass sheet having the antireflection film covering the uneven structure was measured by the method according to JIS Z 8701 (1999).

[0438] Specifically, the spectrophotometer (manufactured by Shimadzu Corporation, trade name: SolidSpec-3700) was used to measure the spectral transmittance, and the light transmittance, i.e., the stimulus value Y defined in JIS Z 8701 (1999) was calculated and set as the above-mentioned light transmittance.

[0439] 〈b ＊ value of the glass sheet〉

[0440] The b ＊ value of the glass sheet was measured by the method according to JIS Z 8729 (2004).

[0441] Specifically, the color index (b ＊ value) prescribed in JIS Z 8729 (2004) was calculated from the transmission spectrum obtained from the above-described spectrophotometric transmittance. The light source used was a D65 light source.

[0442] 〈Light reflectance of the most surface〉

[0443] The light reflectance of the most surface on the first main surface side of the region of the glass sheet having the antireflection film covering the concavo-convex structure was measured by the method according to JIS Z 8701 (1999).

[0444] Specifically, the spectrophotometric reflectance of the most surface on the first main surface side of the region having the antireflection film covering the concavo-convex structure was measured using a spectrophotometer (manufactured by Shimadzu Corporation, trade name: SolidSpec-3700), and the light reflectance, i.e., the reflected stimulus value Y prescribed in JIS Z 8701 (1999) was calculated. Note that the second main surface side of the glass sheet was painted black, and the measurement was performed in a state in which the back surface reflection was eliminated.

[0445] 〈Sheet resistance of the antireflection film〉

[0446] The sheet resistance of the antireflection film provided on the first main surface side of the glass sheet was measured by the method according to JIS K 6271-6 (2008).

[0447] Specifically, a probe was placed at the center of the antireflection film using a measuring device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., device name: Hiresta UP (MCP-HT450 type)), and the sheet resistance of the antireflection film was measured at 10 V for 10 seconds.

[0448] 〈60° specular gloss (%)〉

[0449] The 60° specular gloss (%) of the most surface on the first main surface side of the glass sheet was measured by the method according to JIS Z 8741 (1997).

[0450] Specifically, the 60° specular gloss was measured at the substantially central portion of the plane of the region of the glass sheet having the concavo-convex structure formed on the surface of the first main surface side and the antireflection film using an integrated gloss meter (manufactured by Rhopoint Instruments, Rhopoint IQ). At this time, the back surface reflection of the glass sheet was eliminated by laying a black felt on the second main surface side of the glass sheet.

[0451] 〈Tactile sensation〉

[0452] The tactile sensation of the sliding action of the surface of the region having the concavo-convex structure and the anti-reflection film of the glass plate was evaluated.

[0453] Specifically, the sliding action of one finger was performed on the surface, and pinch-in and pinch-out as the sliding action of two fingers were performed. Then, the feeling of the sliding of the finger in the sliding action of one finger and the feeling of the stop of the finger at the end of the sliding action of two fingers were evaluated. The number of panelists was set to 174, and each of the panelists evaluated the tactile sensation of each glass plate as pass / fail and gave a score of 0 to 10 points, and the average of the scores was used as the tactile sensation level.

[0454] The result of the sensory evaluation was that if the tactile sensation level was 2 points or more, it was judged to be pass, and the higher the tactile sensation level, the more preferable it was.

[0455] <Experiment>

[0456] <Examples 1 to 9>

[0457] A glass plate (Dragontrail (registered trademark), manufactured by AGC Inc.) having a thickness of 1.3 mm was divided into a size of 500 mm x 400 mm using a diamond cutter. The sharp end portion generated by the division was ground to a C chamfer shape using a diamond grindstone having a particle size of No. 400 according to JIS R 6001 (1987).

[0458] Next, the one main surface (first main surface) of the glass plate was subjected to anti-glare treatment based on a wet sandblasting method according to the following procedure.

[0459] A slurry in which abrasive grains were dispersed in water at an abrasive grain concentration (concentration of alumina particles) of 12 vol% was prepared using alumina particles as the abrasive grains. The particle size of the alumina particles according to JIS R 6001 (1987) is shown in Table 1.

[0460] The slurry was delivered to a spray gun using a pump and sprayed to the first main surface of the glass plate in a state of being accelerated using compressed air, and the surface was roughened using wet sandblasting processing.

[0461] The spray pressure, the spray angle of the slurry to the first main surface, and the number of scans in the roughening are shown in Table 1, respectively. In addition, in any of the examples, the projection distance was 70 mm and the delivery speed was 20 mm / s.

[0462] After the wet sandblasting processing, the glass plate was washed with water, and then subjected to etching treatment and washing using hydrofluoric acid, whereby a glass plate having a concavo-convex structure on the surface of the first main surface was obtained. Note that the concentration of hydrogen fluoride in the hydrofluoric acid was 5.0 mass%, and the immersion time was adjusted so that the etching amount of the hydrofluoric acid was the value shown in Table 1.

[0463] Next, an antireflection film is formed on the entire surface of the first main surface having the concavo-convex structure formed thereon.

[0464] For Examples 1 and 9, an antireflection film is provided by alternately forming the low refractive index layer and the high refractive index layer shown below, a total of four layers, using a magnetron sputtering method. The outermost layer is a SiO2layer.

[0465] • Low refractive index layer: SiO2layer, refractive index 1.47 at a wavelength of 550 nm

[0466] • High refractive index layer: Nb2O5layer, refractive index 2.3 at a wavelength of 550 nm

[0467] Specifically, the antireflection film of Examples 1 and 9 is formed according to the following procedure.

[0468] Each layer is formed by sputtering. The conditions are adjusted in the order of a Nb2O5layer having a thickness of 14 nm, a SiO2layer having a thickness of 38 nm, a Nb2O5layer having a thickness of 119 nm, and a SiO2layer having a thickness of 87 nm.

[0469] Each layer is laminated by the flow method. When the film is formed, each layer is formed by introducing a mixed gas in which 10% by volume of oxygen is mixed with argon into the chamber while performing magnetron sputtering at a pressure of 0.3 Pa, a frequency of 20 kHz, a film formation power of 3.8 W / cm2, and a reverse pulse width of 5 μsec, and laminating each layer on the entire surface of the first main surface having the concavo-convex structure. 2

[0470] For Examples 2 to 8, an antireflection film is formed by sequentially forming the high refractive index layer (1), the low refractive index layer (1), the high refractive index layer (2), and the low refractive index layer (2) shown below, a total of four layers, on the concavo-convex structure formed thereon, using a pulse sputtering method. The outermost layer is the low refractive index layer (1).

[0471] • High refractive index layer (1): Mo-Nb-O layer, thickness 14 nm, refractive index 2.1 at a wavelength of 550 nm

[0472] • Low refractive index layer (1): SiO2layer, thickness 35 nm, refractive index 1.47 at a wavelength of 550 nm

[0473] • High refractive index layer (2): Mo-Nb-O layer, thickness 120 nm, refractive index 2.1 at a wavelength of 550 nm

[0474] • Low refractive index layer (2): SiO2layer, thickness 90 nm, refractive index 1.47 at a wavelength of 550 nm

[0475] ​Specifically, the antireflection film of Examples 2 to 9 was formed according to the following procedure.

[0476] While introducing a mixed gas of 39% by volume of oxygen in argon, pulse sputtering was performed using a target in which niobium and molybdenum were mixed at a weight ratio of 80:20 and sintered. The sputtering conditions were a pressure of 0.3 Pa, a frequency of 20 kHz, a power density of 4.0 W / cm 2 , and a reverse pulse width of 5 μsec. Thus, a Mo-Nb-O layer of 14 nm was formed so as to cover the uneven structure of the glass plate. The composition ratio of Mo to Nb in the obtained Mo-Nb-O layer was Mo:Nb = 80:20 (mass %).

[0477] Next, while introducing a mixed gas of 40% by volume of oxygen in argon, pulse sputtering was performed using a silicon target. The sputtering conditions were a pressure of 0.3 Pa, a frequency of 20 kHz, a power density of 3.8 W / cm 2 , and a reverse pulse width of 5 μsec. Thus, a layer composed of silicon oxide (silicon dioxide (SiO2)) of 35 nm in thickness was formed.

[0478] Next, while introducing a mixed gas of 10% by volume of oxygen in argon, pulse sputtering was performed using a target in which niobium and molybdenum were mixed at a weight ratio of 80:20 and sintered, while the pressure was maintained at 0.3 Pa. The sputtering conditions were a frequency of 20 kHz, a power density of 4.0 W / cm 2 , and a reverse pulse width of 5 μsec. Thus, a Mo-Nb-O layer of 120 nm was formed. The composition ratio of Mo to Nb in the obtained Mo-Nb-O layer was Mo:Nb = 80:20 (mass %).

[0479] Next, while introducing a mixed gas of 39% by volume of oxygen in argon, pulse sputtering was performed using a silicon target. The sputtering conditions were a pressure of 0.3 Pa, a frequency of 20 kHz, a power density of 3.8 W / cm 2 , and a reverse pulse width of 5 μsec. Thus, a layer composed of silicon oxide (silicon dioxide (SiO2)) of 90 nm in thickness was formed.

[0480] For Examples 1 to 9, a stain-proof film was further formed on the glass plate on which the antireflection film was formed, so as to cover the entire surface of the antireflection film. The stain-proof film was formed according to the following procedure.

[0481] As the material of the stain-proof layer, a forming material of a fluorine-containing organosilicon compound film was introduced into a heating container of a stain-proof layer forming chamber. As the composition for forming the stain-proof layer, S-550 (manufactured by AGC Inc.) was used.

[0482] Next, the glass plate on which the antireflection film was formed was set in the vacuum chamber, and the antifouling layer-forming composition was supplied to the first main surface to form a film having a thickness of 4 nm.

[0483] Through the above steps, the glass plates of Examples 1 to 9 were obtained.

[0484] Examples 10 to 16

[0485] For Examples 10 to 15, one main surface (first main surface) of the glass plate was subjected to the antiglare treatment based on the frosted method according to the following steps. For Example 16, no antiglare treatment was performed.

[0486] In the antiglare treatment based on the frosted method, first, the glass plate was subjected to a pre-washing treatment by immersing it in 5 mass% hydrofluoric acid for 180 seconds. Next, the glass plate was subjected to washing with pure water and drying, and subjected to frosted processing.

[0487] The frosted processing was performed by immersing the glass plate in a mixed solution of potassium fluoride and hydrogen fluoride at 15°C for 180 seconds. The concentrations of potassium fluoride and hydrogen fluoride in the mixed solution were as described in Table 2.

[0488] Next, the glass plate was subjected to washing with pure water and drying, and subjected to etching processing.

[0489] The etching processing was performed by immersing the glass plate in a mixed solution of hydrogen fluoride and hydrochloric acid at 15°C. The concentration of hydrogen fluoride in the mixed solution was 10 mass%, and the concentration of hydrochloric acid was 4 mass%. The immersion time was adjusted so that the post-etching amount of the etching processing became the value described in Table 2.

[0490] Then, the glass plate was subjected to washing with pure water and drying, and a glass plate having a concavo-convex structure on the surface of the first main surface was obtained.

[0491] Next, for Examples 10 to 15, an antireflection film was formed on the entire surface of the first main surface having the above-described formed concavo-convex structure, and for Example 16, an antireflection film was formed on the entire surface of one main surface. Specifically, for Examples 10 to 12, an antireflection film was formed in the same manner as in Examples 2 to 8, and for Examples 13 to 16, an antireflection film was formed in the same manner as in Example 1 and Example 9.

[0492] Next, for the glass plate on which the antireflection film was formed, an antifouling film was formed in the same manner as in Examples 1 to 9 so as to cover the entire surface of the antireflection film, and the glass plates of Examples 10 to 16 were obtained.

[0493] The results of the evaluation of the obtained glass plates are shown in Tables 1 and 2. In addition, the sheet resistance of the antireflection film of the glass of Examples 1 to 16 was 10 4 Ω / □ or more.

[0494]

[0495]

[0496] From the above results, it is known that even if the value of the average dynamic friction coefficient COF is within an appropriate range, the glass sheet having a small friction variation delta also has insufficient tactile sensation at the time of sliding operation. In addition, it is known that by setting the visual recognition index value T, the glare index value S, and the luminance L ＊ value within an appropriate range, appropriate visual recognition can also be maintained.

[0497] The glass sheet satisfying this characteristic has a correlation with the value of the surface roughness and the transmission haze.

[0498] In the conventional glass sheet manufacturing method, when excellent tactile sensation is to be obtained, the transmission haze becomes large, and it is not possible to achieve a sufficiently low luminance L ＊ value. However, it is known through the research by the present inventors and others that when the wet blasting method is used to form the concavo-convex structure, by reducing the blasting angle of the slurry, it is possible to achieve both excellent tactile sensation and a small transmission haze.

[0499] In addition, it is known that the transmission haze has a correlation with the luminance L ＊ value, and when the transmission haze is large, the luminance L ＊ value also becomes large and the substrate whitens, but by forming the above-described absorption-type anti-reflection film, even if the transmission haze becomes large, it is possible to suppress the whitening of the substrate and achieve a sufficiently low luminance L ＊ value.

[0500] The above describes the preferred embodiments of the present application in detail, but the present application is not limited to the above-described specific embodiments, and various modifications and changes can be made within the scope of the gist of the present application described in the scope of the patent claims.

[0501] This application is based on Japanese Patent Application (Tokugan 2023-106110) filed on June 28, 2023, the content of which is incorporated herein by reference.

[0502] Industrial applicability

[0503] By applying the glass sheet of the present application to a display device, it is possible to maintain excellent visual recognition, and the tactile sensation is also excellent, and thus it is also possible to be favorably used for a display device having a touch panel function.

[0504] Explanation of symbols

[0505] 50 glass sheet

[0506] 51 black plate

[0507] 52 first main surface

[0508] 53 second main surface

[0509] 54 display device

[0510] 70A, 70B, 70C measuring device

[0511] 71 light source

[0512] 75 detector (analysis device)

[0513] 731 second light

[0514] 733 first reflected light

[0515] 735 second reflected light

[0516] 737 third reflected light

Claims

1. A glass sheet having a first main face and a second main face opposite to the first main face, the first main face has a concavo-convex structure at least in a part thereof, a visual recognition index value T of a surface of a region having the concavo-convex structure on the first main face side is 0.85 or more, a glare index value S is 0.80 or more, an average dynamic friction coefficient COF is 0.50 or less, and a friction variation delta exceeds -0.210, The glass sheet has a lightness L in the SCE mode, measured by the method according to ASTM E313-73 standard, of 4.7 or less ＊ value of 4.7 or less, the visual recognition index value T, the glare index value S, the average dynamic friction coefficient COF, and the friction variation delta are quantified by the following methods, respectively; Visual discrimination index value T: Using SMS-1000 manufactured by DM & S Co., Ltd., a glass sheet was set with the first main surface side as the light source side above a slit-shaped white light source of 40 mm in length and 0.1 mm in width at a position of 30 mm, and the brightness of the outermost surface of the area having the concavo-convex structure was measured from the second main surface side of the glass sheet; a camera lens is used with a focal length of 16 mm at an aperture of 5.6, a distance from a surface of the glass sheet on the first main face side to the camera lens is set to 550 mm, a direction parallel to a thickness direction of the glass sheet is set to an angle θ = 0°, an average value of luminance in a range of an angle θ = 0° ± 0.1° is set to Tl, an average value of luminance in a range of an angle θ = 0.7° ± 0.1° is set to T2, an average value of luminance in a range of an angle θ = -0.7° ± 0.1° is set to T3, and a value calculated by the following equation (1) is set to the visual recognition index value T, Visual recognition index value T = 1 - (T2 + T3) / (2 x Tl) Equation (1); S: The glass plate was arranged so as to contact the second major surface side of a display device having a resolution of 264 ppi; in a state in which the display device displayed an image of a green monochrome composed of RGB (0, 255, 0), image analysis was performed using SMS-1000 manufactured by DM&S Co., Ltd. provided on the first major surface side of the glass plate, and the Sparkle value of the surface of the region having the concave-convex structure calculated was set as the glare S a ; the distance d between the SMS-1000 manufactured by DM&S Co., Ltd. and the surface of the first major surface side of the glass plate was 540 mm, the camera lens was a lens having a focal length of 50 mm used at an aperture of 5.6, and, in addition, image analysis was performed under the same conditions for a glass substrate of the same thickness as the glass plate, which was VRD140 glass manufactured by AGC Glass Europe Co., Ltd., and the Sparkle value calculated was set as the glare S s ; the value calculated by the following equation (2) from the values of S a and S s was set as the glare index value S, The glare index value S = 1 - (S a / S s ) Equation (2) the average dynamic friction coefficient COF and the friction variation delta are measured in a static-dynamic friction tester in an environment of room temperature 23°C and humidity 21%, on a surface of a region having the concavo-convex structure on the first main face side of the glass sheet, with a simulated finger sliding at a scan distance 50 mm, a load 100 g, and a scan speed 100 mm / sec, a data acquisition frequency is 1 kHz, the simulated finger is made of polyurethane, and a contact portion with the surface is formed with linear projections in a direction at right angles to a sliding direction at intervals of 0.5 mm in an area of 10 x 15 mm; here, a time when the dynamic friction coefficient becomes the maximum is traced back in time, a time when the dynamic friction coefficient first becomes 0 or less is set to a motion start time, a time after {(the motion start time) + (0.75 x the scan distance / the scan speed)} is set to a motion end time, a time when the dynamic friction coefficient first becomes 5 or less is set to a motion end time, a value calculated by the following equation (3) is set to the average dynamic friction coefficient COF, and a value calculated by the following equation (4) is set to the friction variation delta, Average dynamic friction coefficient COF = an average value of the dynamic friction coefficient at a time of (the motion start time to the motion end time) ± 0.2 seconds Equation (3), Friction variation delta = (the maximum dynamic friction coefficient after the motion end time) - (the average dynamic friction coefficient COF) Equation (4).

2. The glass sheet of claim 1, wherein, the first main face further has an anti-reflection film at least in a part thereof, the anti-reflection film covers at least a part of the concavo-convex structure, The light transmittance measured at the surface on the first main surface side of the region of the glass sheet having the antireflection film is 20 to 85%, The b value of the transmission color under D65 light source measured in accordance with JIS Z 8729 (2004) is 5 or less ＊ value is 5 or less, The light reflectance measured at the surface on the first main surface side of the region of the glass sheet having the antireflection film covering the concavo-convex structure is 1% or less, The anti-reflection film has a sheet resistance of 10 4 Ω / □ or more.

3. The glass sheet of claim 2, wherein, The surface on the first main surface side of the region having the concavo-convex structure and the antireflection film has a transmission haze of 15% or more as measured by the method according to JIS K 7136 (2000).

4. The glass sheet of claim 2, wherein, The antireflection film is a stacked structure in which layers having different refractive indexes are alternately stacked two or more layers, The main component of the dielectric layer in the stacked structure is an oxide of at least one selected from Si, Nb, Ti, Zr, Ta, Al, Sn, and In, or a nitride of at least one of Si and Al, At least one of the dielectric layers has dispersed therein fine particles of at least one selected from Ag, Mo, W, Cu, Au, Pd, Pt, Ir, Ni, Co, Fe, Cr, C, TiC, SiC, TiN, and CrN.

5. The glass sheet of claim 2, wherein, The antireflection film is a stacked structure in which layers having different refractive indexes are alternately stacked two or more layers, The main component of at least one of the layers in the stacked structure is an oxide of Si, The main component of at least one other of the layers in the stacked structure is a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, The content of the element of the Group B with respect to the total of the element of the Group A and the element of the Group B in the mixed oxide is less than 50 mass%.

6. The glass sheet of claim 2, wherein, The surface on the first main surface side of the region having the concavo-convex structure and the antireflection film has a surface roughness in which the element average length Rsm of the roughness curve is less than 26 μm, the arithmetic average roughness Ra is 0.12 μm or more, the skewness Rsk is from -1 to 1, and the kurtosis Rku is from 2 to 4.

7. The glass sheet of claim 1, wherein, The surface on the first main surface side of the region having the concavo-convex structure has a transmission haze of less than 15% as measured by the method according to JIS K 7136 (2000).

8. The glass sheet of claim 7, wherein, The surface on the first main surface side of the region having the concavo-convex structure has a surface roughness in which the element average length Rsm of the roughness curve is 26 μm or more, the skewness Rsk is from -4 to -1.5, and the kurtosis Rku is from 5 to 20.

9. The glass sheet of claim 7, wherein, The first main surface further has an antireflection film at least in part, The antireflection film covers at least a part of the concavo-convex structure, The antireflection film is a stacked structure in which a low-refractive-index layer and a high-refractive-index layer are alternately stacked two or more layers, The main component of the high-refractive-index layer is at least one selected from SiN, TiO2, Nb2O5, Ta2O5, and ZrO2.

10. The glass sheet according to any one of claims 1-9, wherein, At least a part on the second main surface has a printed layer.

11. The glass sheet according to any one of claims 1-9, wherein, The glass sheet is chemically strengthened glass.

12. The glass sheet according to any one of claims 1 to 9, which is used for a cover glass of a display device for a vehicle.

13. A display device for a vehicle, comprising a cover glass made of the glass sheet according to claim 12 and a display panel.

14. A method for manufacturing a glass sheet, the method being the method for manufacturing the glass sheet according to any one of claims 1 to 9, the glass sheet has a first main surface and a second main surface opposite to the first main surface, the method for manufacturing the glass sheet includes forming a concavo-convex structure on at least a part of the first main surface.

15. The method of making a glass sheet according to claim 14, wherein, the forming of the concavo-convex structure includes: immersing the glass sheet in a solution containing potassium fluoride and hydrogen fluoride; and then immersing the glass sheet in a solution containing hydrogen fluoride; the method further includes forming an anti-reflection film in a manner to cover at least a part of the concavo-convex structure.

16. The method of making a glass sheet according to claim 14, wherein, the forming of the concavo-convex structure includes: roughening the first main surface of the glass sheet by spraying a slurry thereon; and then etching the glass sheet by immersing the glass sheet in a solution containing hydrogen fluoride.

17. The method of making a glass sheet according to claim 16, wherein, the slurry is sprayed at an angle of 70° or less with respect to the first main surface.

18. The method of making a glass sheet according to claim 16, wherein, the forming of the concavo-convex structure includes: immersing the glass sheet in a solution containing potassium fluoride and hydrogen fluoride; and then immersing the glass sheet in a solution containing hydrogen fluoride; the method further includes forming an anti-reflection film in a manner to cover at least a part of the concavo-convex structure.

19. A method for selecting a glass sheet according to any one of claims 1 to 9.

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