Anti-glare glass plate

Abstract

To provide an anti-glare glass plate that achieves excellent visibility on the display surface, by simultaneously suppressing external light reflection and glare on the display surface, when used in a display device.SOLUTION: Provided is a glass plate 1 having anti-glare functionality, comprising an uneven portion 2 on at least part of a main surface 1a of the glass plate 1, wherein the uneven portion 2 has unevenness in which the arithmetic average height Sa of the contour curved surface is 15 nm or more and 300 nm or less, and the ratio (Sdq / RSm1) of the root mean square slope Sdq of the contour curved surface to the average length RSm1 of roughness curve elements is 0.05 or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an antiglare glass plate. [Background technology]

[0002] Conventionally, in display devices such as displays, attempts have been made to improve the visibility of the display surface by roughening the surface of a cover member constituting the display device and suppressing the reflection of the background on the display surface, etc. However, since roughening the surface of the cover member can cause the color to become whitish and cause glare called sparkle, methods for solving these problems have been studied.

[0003] The following Patent Document 1 discloses a transparent glass plate having at least one antiglare surface. In Patent Document 1, the antiglare surface has a first RMS surface roughness R of up to 300 nm measured in a lateral spatial periodicity range of 40 μm to 640 μm. 長 , the second RMS surface roughness R measured with a lateral spatial period of less than 20 μm 短 , and the third RMS surface roughness R in the range of 60 nm to 600 nm measured without surface wavelength filtering. 全 and the ratio (R 長 / R 短 ) is less than 3.9. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6013378 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the higher the resolution of the display device, the more prominent the sparkle caused by roughening the display surface of the cover member becomes, and the visibility of the display surface is likely to deteriorate. Of course, reducing the degree of roughening on the display surface of the cover member is effective in suppressing sparkle, but on the other hand, there is a problem that external light is likely to be reflected on the display surface and the antiglare property deteriorates.

[0006] An object of the present invention is to provide an antiglare glass plate that can achieve both suppression of reflection of external light and suppression of glare on the display surface when used in a display device, and has excellent visibility of the display surface.

Means for Solving the Problems

[0007] Each aspect of the antiglare glass plate for solving the above problems will be described.

[0008] The antiglare glass plate according to Aspect 1 of the present invention is a glass plate having antiglare properties, and at least a part of the main surface of the glass plate has uneven portions. The uneven portions have an arithmetic mean height Sa of the contour surface of 15 nm or more and 300 nm or less, and a ratio (Sdq / RSm1) of the root mean square gradient Sdq of the contour surface to the average length RSm1 of the roughness curve elements of 0.05 or more. It is characterized by having unevenness.

[0009] The antiglare glass plate of Aspect 2 preferably has, in Aspect 1, the unevenness having a skewness Ssk of the contour surface having a negative value and a kurtosis Sku of the contour surface of 3.6 or more.

[0010] The antiglare glass plate of Aspect 3 preferably has, in Aspect 1 or Aspect 2, the unevenness satisfying the relationship of Sp < Sv between the maximum peak height Sp of the contour surface and the maximum valley depth Sv of the contour surface.

[0011] The antiglare glass plate of Aspect 4 preferably has, in any one of Aspects 1 to 3, the unevenness having a root mean square gradient Sdq of the contour surface of 0.25 or more.

[0012] In the anti-glare glass plate of aspect 5, in any one of aspects 1 to 4, the unevenness preferably has a mean length RSm1 of roughness curve elements of 8.5 μm or less.

[0013] The anti-glare glass plate of aspect 6 is preferably any one of aspects 1 to 5, in which when the irregularities are first irregularities, the irregular portion further has second irregularities having an average length of roughness curve elements longer than the average length RSm1 of the roughness curve elements of the first irregularities, and the average length RSm2 of the roughness curve elements of the second irregularities is 10 μm or more. Effect of the Invention

[0014] Effects of the Invention According to the present invention, it is possible to provide an antiglare glass plate which, when used in a display device, can simultaneously suppress both reflection of external light and glare on the display surface, thereby providing excellent visibility on the display surface. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view showing an antiglare glass plate according to one embodiment of the present invention. [Diagram 2] FIG. 11 is a schematic cross-sectional view showing a modified antiglare glass plate. [Diagram 3] 13 is a diagram for explaining a measured cross-sectional curve in a modified example of the concave-convex portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0017] (Anti-glare glass plate) FIG. 1 is a schematic cross-sectional view showing an antiglare glass plate according to one embodiment of the present invention.

[0018] The anti-glare glass plate 1 is a glass plate provided with so-called anti-glare properties that suppresses reflection of external light, etc. In this embodiment, the anti-glare glass plate 1 has a flat rectangular shape. However, the shape of the anti-glare glass plate 1 is not particularly limited, and may be a flat plate having a circular or polygonal outline, a flat plate having a generally curved shape, or a spherical or aspherical lens shape. It is preferable that the thickness of the anti-glare glass plate 1 is uniform, but the anti-glare glass plate 1 may have a shape in which the thickness varies depending on the location.

[0019] The material of the antiglare glass plate 1 is not particularly limited, but examples thereof include silicate-based glasses such as aluminosilicate glass, alkali-containing aluminosilicate glass, borosilicate glass, lithium silicate glass, and soda-lime silicate glass. Here, silicate-based glass refers to glass containing 10 mass % or more of SiO2 as a glass composition.

[0020] The anti-glare glass plate 1 has a first main surface 1a and a second main surface 1b which face each other. The first main surface 1a and the second main surface 1b are the surfaces of the anti-glare glass plate 1. In this embodiment, an uneven portion 2 is provided on a part of the first main surface 1a of the anti-glare glass plate 1. The uneven portion 2 is, for example, a display surface of a display device such as a display.

[0021] The first main surface 1a of the anti-glare glass plate 1 also has an unprocessed portion 3 that has not been processed to provide the uneven portion 2. In this embodiment, the entire second main surface 1b of the anti-glare glass plate 1 also constitutes the unprocessed portion 3 that has not been processed to provide the uneven portion 2. However, in the present invention, the uneven portion 2 may also be provided on the second main surface 1b of the anti-glare glass plate 1. That is, the uneven portion 2 may be provided on both main surfaces 1a, 1b of the anti-glare glass plate 1.

[0022] In the present invention, it is sufficient that the uneven portion 2 is provided on at least a part of the first main surface 1a of the anti-glare glass plate 1. The uneven portion 2 is provided over preferably 1% or more of the area of ​​the first main surface 1a of the anti-glare glass plate 1, more preferably 30% or more, and even more preferably 50% or more.

[0023] Fig. 2 is a schematic cross-sectional view showing a modified anti-glare glass plate. As in the anti-glare glass plate 10 shown in Fig. 2, the uneven portion 2 may be provided on the entire first main surface 1a of the anti-glare glass plate 10. Hereinafter, the modified anti-glare glass plate 10 will also be collectively referred to as the anti-glare glass plate 1.

[0024] The thickness of the antiglare glass plate 1 is not particularly limited and can be, for example, 30 μm or more and 5 mm or less.

[0025] In this embodiment, the uneven portion 2 of the anti-glare glass plate 1 has unevenness in which the arithmetic mean height Sa of the contour surface is 15 nm or more and 300 nm or less, and the ratio (Sdq / RSm1) of the root mean square gradient Sdq of the contour surface to the average length RSm1 of the roughness curve elements is 0.05 or more.

[0026] The "arithmetic mean height Sa of a contour surface" is a parameter defined by ISO 25178, which is a parameter obtained by expanding a measured cross-sectional curve showing the cross-sectional shape of the unevenness into a surface. Specifically, the arithmetic mean height Sa of a contour surface can be calculated from the average of the absolute values ​​of the heights Zn of each point relative to the average plane of the surface in a specified three-dimensional region (Sa=(Σ|Zn|) / n). Hereinafter, the "arithmetic mean height Sa of a contour surface" may be simply referred to as the "arithmetic mean height Sa."

[0027] The "root-mean-square gradient Sdq of a contour surface" is a parameter defined by ISO 25178, which is a parameter obtained by expanding a measured cross-sectional curve that indicates the cross-sectional shape of a concave or convex surface into a surface. Specifically, the root-mean-square gradient Sdq of a contour surface is a parameter calculated by the root-mean-square of the inclination at all points in a defined region. Hereinafter, the "root-mean-square gradient Sdq of a contour surface" may be simply referred to as the "root-mean-square gradient Sdq."

[0028] The "average length RSm1 of roughness curve elements" refers to the "average length RSm of roughness curve elements" defined by JIS B0601:2013, and is referred to as the "average length RSm1 of roughness curve elements" to distinguish it from the "average length RSm2 of roughness curve elements" of the second irregularity described below. Therefore, the "average length RSm1 of roughness curve elements" is a parameter that represents the average pitch between adjacent concave and convex portions in a contour curve that shows the cross-sectional shape of the irregularities. Note that hereinafter, the "average length RSm1 of roughness curve elements" may be simply referred to as the "average length RSm1".

[0029] The anti-glare glass plate 1 of the present embodiment has the above-mentioned configuration, and therefore when used in a display device such as a display, it is possible to suppress both reflection of external light and glare on the display surface, thereby improving the visibility of the display surface.

[0030] Conventionally, the higher the resolution of a display device, the more noticeable the sparkle caused by roughening the display surface of the glass plate, which is the cover member, becomes, and the visibility of the display surface is easily reduced. Although reducing the degree of roughening of the display surface of the glass plate, which is the cover member, is effective in suppressing sparkle, there is a problem in that reflection of external light on the display surface is easily caused, and the anti-glare properties are reduced.

[0031] In response to this, the inventors focused on the arithmetic mean height Sa of the uneven portion of a glass plate used in a cover member of a display device and the above-mentioned ratio (Sdq / RSm1), and discovered that by setting the arithmetic mean height Sa of the uneven portion of the glass plate and the above-mentioned ratio (Sdq / RSm1) within specific ranges, it is possible to suppress both the reflection of external light and glare on the display surface, thereby improving the visibility of the display surface.

[0032] More specifically, the anti-glare glass plate 1 of this embodiment can have a shape with a fine unevenness pitch and a large unevenness gradient by making the unevenness constituting the uneven portion 2 have an arithmetic mean height Sa of 15 nm or more and the above-mentioned ratio (Sdq / RSm1) of 0.05 or more. Therefore, when the anti-glare glass plate 1 of this embodiment is used in a display device, it can simultaneously suppress both reflection of external light and glare on the display surface, thereby improving the visibility of the display surface.

[0033] Furthermore, the anti-glare glass plate 1 of this embodiment can reduce haze by setting the arithmetic mean height Sa of the concaves and convexes constituting the concave-convex portion 2 to 300 nm or less. Therefore, the anti-glare glass plate 1 of this embodiment can improve the visibility of the display surface from this point of view as well.

[0034] The arithmetic mean height Sa of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is 15 nm or more, preferably 18 nm or more, more preferably 22 nm or more, and 300 nm or less, preferably 200 nm or less, more preferably 150 nm or less.

[0035] When the arithmetic mean height Sa of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is equal to or greater than the above lower limit, reflection of external light on the display surface can be further suppressed and visibility of the display surface can be further improved when the anti-glare glass plate 1 is used in a display device. When the arithmetic mean height Sa of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is equal to or less than the above upper limit, the haze of the anti-glare glass plate 1 can be further reduced and visibility of the display surface can be further improved when the anti-glare glass plate 1 is used in a display device.

[0036] The ratio (Sdq / RSm1) of the root-mean-square gradient Sdq of the unevenness to the average length RSm1 of the unevenness portion 2 of the anti-glare glass plate 1 is 0.05 or more, preferably 0.07 or more, more preferably 0.08 or more, and is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.30 or less.

[0037] When the ratio (Sdq / RSm1) of the concave-convex portion 2 of the anti-glare glass plate 1 is equal to or greater than the lower limit, the display surface can be simultaneously suppressed to a higher level to suppress both reflection of external light and glare when the anti-glare glass plate 1 is used in a display device, and the visibility of the display surface can be further improved. The upper limit of the ratio (Sdq / RSm1) of the concave-convex portion 2 of the anti-glare glass plate 1 is not particularly limited, but from the viewpoint of preventing wear and adhesion of dirt from occurring in the concave-convex portion 2 of the anti-glare glass plate 1 and making the anti-glare glass plate 1 easier to manufacture, it is desirable that the ratio be equal to or less than the upper limit.

[0038] The root mean square gradient Sdq of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is preferably 0.25 or more, more preferably 0.28 or more, further preferably 0.30 or more, and is preferably 1.00 or less.

[0039] When the root-mean-square gradient Sdq of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is equal to or greater than the above lower limit, when the anti-glare glass plate 1 is used in a display device, it is possible to achieve a higher level of both suppression of reflection of external light and suppression of glare on the display surface, and the visibility of the display surface can be further improved. The upper limit of the root-mean-square gradient Sdq of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 is not particularly limited, but from the viewpoints of making it more difficult for wear and adhesion of dirt to occur in the uneven portion 2 of the anti-glare glass plate 1 and making it even easier to manufacture the anti-glare glass plate 1, it is desirable for it to be equal to or less than the above upper limit.

[0040] The average length RSm1 of the irregularities in the irregularity portion 2 of the anti-glare glass plate 1 is preferably 1.0 or more, more preferably 2.0 μm or more, and preferably 8.5 μm or less, more preferably 8.0 μm or less, and further preferably 7.0 μm or less.

[0041] When the average length RSm1 of the concave-convex portions 2 of the anti-glare glass plate 1 is equal to or less than the upper limit, glare on the display surface can be further suppressed and visibility of the display surface can be further improved when the anti-glare glass plate 1 is used in a display device. The lower limit of the average length RSm1 of the concave-convex portions 2 of the anti-glare glass plate 1 is not particularly limited, but from the viewpoint of making the anti-glare glass plate 1 easier to manufacture, it is desirably equal to or more than the lower limit.

[0042] In this embodiment, it is preferable that the skewness Ssk (hereinafter may be simply referred to as "skewness Ssk") of the contour curved surface of the concave-convex portion 2 of the anti-glare glass plate 1 has a negative value, and the kurtosis Sku (hereinafter may be simply referred to as "kurtosis Sku") of the contour curved surface is 3.6 or more. In this case, when the anti-glare glass plate 1 is used in a display device, it is possible to achieve a higher level of both suppression of reflection of external light and suppression of glare on the display surface, and the visibility of the display surface can be further improved.

[0043] The skew Ssk of the unevenness in the uneven portion 2 of the antiglare glass plate 1 is preferably -10 or more, more preferably -5 or more, preferably less than 0, and more preferably -0.1 or less. Further, the kurtosis Sku of the unevenness in the uneven portion 2 of the antiglare glass plate 1 is preferably 3.6 or more, more preferably 4 or more, preferably 25 or less, and more preferably 20 or less.

[0044] In the present embodiment, it is preferable that the maximum peak height Sp of the contour surface of the unevenness in the uneven portion 2 of the antiglare glass plate 1 (hereinafter, may be simply referred to as "maximum peak height Sp") and the maximum valley depth Sv of the contour surface (hereinafter, may be simply referred to as "maximum valley depth Sv") satisfy the relationship of Sp < Sv. In this case, when the antiglare glass plate 1 is used for a display device, it is possible to achieve both suppression of reflection of external light and suppression of flicker at a higher level on the display surface, and the visibility of the display surface can be further improved.

[0045] The maximum peak height Sp of the unevenness in the uneven portion 2 of the antiglare glass plate 1 is preferably 50 nm or more, more preferably 100 nm or more, preferably 1500 nm or less, and more preferably 1000 nm or less. Further, the maximum valley depth Sv of the unevenness in the uneven portion 2 of the antiglare glass plate 1 is preferably 100 nm or more, more preferably 200 nm or more, preferably 2000 nm or less, and more preferably 1500 nm or less.

[0046] The maximum height Sz of the contour surface of the unevenness in the uneven portion 2 of the antiglare glass plate 1 (hereinafter, may be simply referred to as "maximum height Sz") is preferably 150 nm or more, more preferably 250 nm or more, further preferably 400 nm or more, and even more preferably 1000 nm or more, preferably 3500 nm or less, and more preferably 2500 nm or less. In this case, when the antiglare glass plate 1 is used for a display device, it is possible to achieve both suppression of reflection of external light and suppression of flicker at a higher level on the display surface, and the visibility of the display surface can be further improved.

[0047] The skewness Ssk, kurtosis Sku, maximum peak height Sp, maximum valley depth Sv, and maximum height Sz of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 can be measured in accordance with ISO 25178.

[0048] In addition, when the unevenness having the above-mentioned average length RSm1 is defined as the first unevenness, the unevenness portion 2 of the anti-glare glass plate 1 may further have a second unevenness having a larger average length RSm of roughness curve elements than the first unevenness. More specifically, as shown in Fig. 3, the measured cross-sectional curve of the unevenness portion 2 may have a first unevenness which is a minute unevenness and a second unevenness which is a large unevenness. In this case, the touch of the unevenness portion 2 of the anti-glare glass plate 1 and the writing comfort with a pen when the anti-glare glass plate 1 is used in a pen input device described later can be further improved.

[0049] The average length RSm2 of the roughness curve elements of the second irregularity is preferably 10 μm or more, more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 300 μm or more, and preferably 3000 μm or less, more preferably 2000 μm or less, even more preferably 1000 μm or less.

[0050] The "average length RSm2 of the roughness curve element" is a value obtained when the cutoff value of the high-pass filter λc for cutting off long wavelength components from the contour curve showing the cross-sectional shape of the uneven portion 2 is set to a value five times the average length RSm1 of the first unevenness, and the cutoff value of the low-pass filter λs for cutting off short wavelength components from the contour curve showing the cross-sectional shape of the uneven portion 2 is set to 27 μm. The cutoff value of the high-pass filter λc of the second unevenness can be a value five times the value of the provisional average length RSm of the roughness curve element obtained when the uneven portion 2 is provisionally measured without a filter. The "average length RSm2 of the roughness curve element" can be measured in accordance with JIS B0601:2013, similar to the average length RSm1 of the first unevenness. Hereinafter, the "average length RSm2 of the roughness curve element" may be simply referred to as the "average length RSm2".

[0051] The maximum height roughness Rz of the second irregularities is preferably 5 nm or more, more preferably 15 nm or more, and preferably 1500 nm or less, more preferably 1000 nm or less. The maximum height roughness Rz of the second irregularities can be measured in accordance with JIS B0601:2013 under the same conditions as those for the average length RSm2.

[0052] The haze of the anti-glare glass plate 1 in the wavelength range of 380 nm to 780 nm is preferably 3% or more, more preferably 8% or more, and even more preferably 15% or more, and is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. In this case, when the anti-glare glass plate 1 is used in a display device, the visibility of the display surface can be further improved.

[0053] (Method of manufacturing anti-glare glass plate) Next, an example of a method for producing the anti-glare glass plate 1 will be described.

[0054] The unevenness (first unevenness) in the uneven portion 2 of the anti-glare glass plate 1 can be formed, for example, by carrying out a surface treatment such as a wet blasting treatment.

[0055] Wet blasting is a process in which abrasive grains made of solid particles such as alumina are uniformly mixed with a liquid such as water to form a slurry, which is then sprayed at high speed from a spray nozzle (such as a round nozzle) using compressed air onto a workpiece (such as an original glass plate) to create fine irregularities on the workpiece.

[0056] In wet blasting, when the slurry is sprayed at high speed and collides with the workpiece, the abrasive particles in the slurry scrape, hit, and rub the surface of the workpiece, forming fine irregularities on the surface of the workpiece.

[0057] In this case, the abrasive grains sprayed onto the workpiece and the pieces of the workpiece scraped off by the abrasive grains are washed away by the liquid sprayed onto the workpiece, so that fewer particles remain on the workpiece.

[0058] In wet blasting, when the slurry is sprayed onto the workpiece, the liquid carries the abrasive grains to the workpiece, making it easier to use finer abrasive grains than in dry sandblasting, and the impact when the abrasive grains collide with the workpiece is smaller, making it possible to perform precise processing. Wet blasting also has the characteristic that it is easy to form unevenness such that the maximum peak height Sp is less than the maximum valley depth Sv.

[0059] In the wet blasting process, the grain size of the abrasive grains can be, for example, an average grain size of 0.5 μm or more and 50 μm or less. The scanning pitch (scanning interval) of the nozzle can be, for example, 10 μm or more and 3000 μm or less. The number of scanning times of the nozzle (the number of times the same place is scanned) can be, for example, 1 time or more and 5 times or less. The ejection pressure (processing pressure) of the slurry can be, for example, 0.1 MPa or more and 0.35 MPa or less. In addition, the scanning speed (movement speed) of the nozzle can be, for example, 0.1 mm / s or more and 80 mm / s or less.

[0060] In addition, the arithmetic mean height Sa, maximum peak height Sp, maximum valley depth Sv, and maximum height Sz of the unevenness in the uneven portion 2 of the anti-glare glass plate 1 can be increased by increasing the grain size of the abrasive grains in the wet blasting process, increasing the processing pressure, decreasing the nozzle scanning speed, and increasing the number of nozzle scans. Regarding the root-mean-square gradient Sdq of the unevenness (ratio (Sdq / RSm1)), the behavior of the root-mean-square gradient Sdq of the unevenness and the average length RSm1 of the unevenness are in a trade-off relationship with the grain size of the abrasive grains, processing pressure, nozzle scanning speed, and number of nozzle scans. Therefore, the magnitude of the root-mean-square gradient Sdq of the unevenness (ratio (Sdq / RSm1)) can be adjusted by balancing each of them.

[0061] In addition, by reducing the grain size of the abrasive grains in the wet blasting process, by reducing the processing pressure, or by increasing the nozzle scanning speed, the average length RSm1 of the irregularities in the irregular portion 2 of the anti-glare glass plate 1 and the root-mean-square gradient Sdq of the irregularities can be reduced.

[0062] In addition, the ratio (Sdq / RSm1) can be increased by increasing the processing pressure in the wet blasting process while decreasing the grain size of the abrasive grains, or by increasing the grain size of the abrasive grains while increasing the nozzle scanning speed.

[0063] When the second unevenness described above is provided on the uneven portion 2, the second unevenness can be formed, for example, by increasing the scanning pitch (scanning interval) of a nozzle such as a round nozzle in the wet blasting process for forming the first unevenness. In this case, an area is created where the processing marks from the nozzle do not interfere, and in addition to the minute first unevenness, a second unevenness with a large interval that matches the scanning interval of the nozzle is formed.

[0064] When both the first and second irregularities are formed in the irregular portion 2, the scanning interval of the nozzle can be, for example, 10 μm or more and 3000 μm or less. On the other hand, when only the first irregularities are formed, the scanning interval of the nozzle can be, for example, 1 μm or more and 300 μm or less, the nozzle aperture can be made larger than 1 mm, and the nozzle jetting interval can be made wider than 3 mm.

[0065] The maximum height roughness Rz of the second irregularities can be increased by increasing the processing pressure in the wet blasting process or by increasing the grain size of the abrasive grains.

[0066] Moreover, by increasing the scanning interval of the nozzle in the wet blasting process, the average length RSm2 of the roughness curve elements can be increased.

[0067] (Other embodiments) An anti-reflection film may be provided on the first main surface 1a of the anti-glare glass plate 1. The anti-reflection film may be provided on the second main surface 1b of the anti-glare glass plate 1, or may be provided on both the first main surface 1a and the second main surface 1b of the anti-glare glass plate 1.

[0068] The anti-reflection film is preferably a dielectric multilayer film. In this case, when the anti-glare glass plate 1 is used in a display device, the image clarity on the display surface can be further improved. As the dielectric multilayer film, for example, a multilayer film including a high refractive index film having a relatively high refractive index and a low refractive index film having a relatively low refractive index can be used. The dielectric multilayer film is preferably a multilayer film in which a high refractive index film having a relatively high refractive index and a low refractive index film having a relatively low refractive index are alternately laminated.

[0069] Examples of materials for the high refractive index film include niobium oxide, titanium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silicon nitride, aluminum oxide, and aluminum nitride.

[0070] Examples of materials for the low refractive index film include silicon oxide, aluminum oxide, and magnesium fluoride.

[0071] The thickness of each layer constituting the antireflection film can be, for example, 1 nm or more and 500 nm or less, preferably 2 nm or more, more preferably 5 nm or more, and preferably 300 nm or less, more preferably 200 nm or less.

[0072] The total number of layers constituting the anti-reflection film is not particularly limited. The total number of layers constituting the anti-reflection film is preferably 2 layers or more, and preferably 8 layers or less. By keeping the number within this range, it is possible to obtain an effective and easily formable film.

[0073] The total film thickness of the antireflection film is not particularly limited, but can be, for example, 50 nm or more and 1000 nm or less, preferably 75 nm or more, more preferably 100 nm or more, and preferably 750 nm or less, more preferably 500 nm or less.

[0074] The anti-reflection film can be formed by, for example, a sputtering method, a CVD method, a vacuum deposition method, or the like.

[0075] Other films, such as an antifouling film, a decorative film, or a decorative coating, may be provided on the first main surface 1a of the antiglare glass plate 1. The other films may be provided on the second main surface 1b of the antiglare glass plate 1, or may be provided on both the first main surface 1a and the second main surface 1b of the antiglare glass plate 1.

[0076] The antifouling film is a film for preventing fingerprints from adhering and imparting water repellency and oil repellency. The antifouling film preferably contains a fluorine-containing polymer containing silicon in the main chain. As the fluorine-containing polymer, for example, a polymer having a -Si-O-Si- unit in the main chain and a water-repellent functional group containing fluorine in the side chain can be used. The fluorine-containing polymer can be synthesized, for example, by dehydration condensation of silanol.

[0077] Examples of decorative films and decorative coatings include resins such as polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polypropylene (PP), polyethylene terephthalate (PET), acrylic, urethane, and fluorine-based resins, metal foils, and laminates thereof.

[0078] The anti-glare glass plate 1 of this embodiment can be suitably used as a cover member provided on the front surface of a display device such as a display of an electronic device. In this case, the anti-glare glass plate 1 may be used in a pen input device that allows input operation (pointing operation) of characters, figures, etc., to be performed using an input means such as an input pen or a fingertip. Alternatively, the anti-glare glass plate 1 may be used in a medical display, a display for a game device, digital signage, lighting, etc.

[0079] The present invention will be described in more detail below with reference to specific examples. The present invention is not limited to the following examples, and can be modified as appropriate within the scope of the present invention.

[0080] (Examples 1 to 8) First, an alkali-containing aluminosilicate glass plate having a thickness of 0.55 mm was prepared as a glass plate. Next, one main surface of the prepared glass plate was subjected to a wet blasting treatment to form projections and recesses, thereby obtaining an antiglare glass plate (glass plate).

[0081] In the wet blasting process, first, 3 wt% of abrasive grains made of alumina with a grain size of #4000 to #8000, 96.8 wt% of water, and 0.2 wt% of dispersant were uniformly mixed to prepare a slurry. Next, the glass plate was placed in a substantially vertical position, and the round nozzle was moved and scanned over the entire main surface of one side of the glass plate at a scanning speed of 0.5 mm / s to 30.0 mm / s, and the prepared slurry was sprayed from the round nozzle using air with a processing pressure of 0.20 MPa to 0.35 MPa, thereby subjecting the glass plate to wet blasting. The round nozzle is a nozzle that narrows the cross-sectional area of ​​the slurry spray port to a small area relative to the surface area of ​​the glass plate, and sprays the slurry partially onto the surface of the glass plate. In addition, in Examples 1 to 5, the scanning interval of the round nozzle was set to 350 μm, so that the overlap of the processed areas became large, and therefore the second unevenness was not formed. On the other hand, in Examples 6 to 8, the scanning interval of the round nozzle was set to 500 μm to 2000 μm to form the first and second irregularities. The conditions of the wet blasting (WB) treatment in Examples 1 to 8 are as shown in Table 1 below.

[0082] [Table 1]

[0083] (Comparative Examples 1 to 7) First, a slurry was prepared by uniformly mixing 10 vol% to 13 vol% abrasive grains made of alumina with a grain size of #320 to #8000 and pure water. Next, a nozzle was moved and scanned at a scanning speed of 5.0 mm / s to 50.0 mm / s over the entire main surface of one side of a glass plate (an alkali-containing aluminosilicate glass plate with a thickness of 0.55 mm), and the prepared slurry was sprayed from the nozzle using air with a processing pressure of 0.10 MPa to 0.32 MPa, thereby performing a wet blasting treatment on the main surface of one side of the glass plate. As a result, preliminary irregularities were formed on the main surface of one side of the glass plate.

[0084] The glass plate with the preliminary irregularities formed on one main surface of the glass plate was immersed in an etching solution consisting of 2.0 wt% hydrofluoric acid (hydrofluoric acid), 0 wt% to 50.0 wt% sulfuric acid, and 48.0 wt% to 98.0 wt% pure water, and was left at a liquid temperature of 30°C for 10 to 30 minutes, thereby performing an etching treatment. As a result, the final irregularities were formed from the preliminary irregularities, and a glass plate was obtained. The conditions for the wet blasting (WB) treatment and the etching treatment in Comparative Examples 1 to 7 are as shown in Table 2 below.

[0085] [Table 2]

[0086] Comparative Example 8 An alkali-containing aluminosilicate glass plate having a thickness of 0.55 mm was used as it was as a glass plate without being subjected to any treatment.

[0087] [Evaluation method] (Surface roughness evaluation) The surface roughness parameters of one main surface that had been subjected to each treatment were measured for the glass plates obtained in Examples 1 to 8 and Comparative Examples 1 to 7. In addition, the surface roughness parameters of one main surface (untreated) for the glass plate of Comparative Example 8 were measured.

[0088] For the unevenness (first unevenness) of Examples 1 to 8 and Comparative Examples 1 to 8, the arithmetic mean height Sa, maximum height Sz, skewness Ssk, kurtosis Sku, maximum peak height Sp, maximum valley depth Sv, root mean square gradient Sdq, and average length RSm1 were measured as surface roughness parameters to be measured using a laser microscope (manufactured by Keyence Corporation, "VK-X250"). The average length RSm1 was measured in accordance with JIS B0601:2013. The other surface roughness parameters were measured in accordance with ISO 25178. In addition, the measurement of each surface roughness parameter was performed in a region of a measurement area of ​​32 μm × 24 μm, the number of acquired data was 1024 × 768 pixels, and the reference length was 1 / 5 of the measurement area.

[0089] For the second irregularities of Examples 6 to 8, the average length RSm2 and maximum height roughness Rz were measured as parameters of the surface roughness to be measured using a white light interference microscope (Zygo, "New View 7300"). The average length RSm2 and maximum height roughness Rz were measured in accordance with JIS B0601:2013. In addition, the measurement of each surface roughness parameter in the second irregularities was performed using a 2.5x objective lens and a 0.5x zoom lens, for a measurement area of ​​5664 μm×4248 μm, with the camera pixel count set to 640×480 and the number of integrations set to 1. In addition, when measuring each surface roughness parameter in the second irregularities, the cutoff value λc1 of the high-pass filter λc was set to 5 times the interval of the average length RSm1, and the cutoff value λs1 of the low-pass filter λs was set to 27 μm.

[0090] (Hayes's rating) The haze was evaluated for the glass plates of Examples 1 to 8 and Comparative Examples 1 to 8. The haze was measured in the wavelength range of 380 nm to 780 nm. The haze was measured using an ultraviolet-visible-near infrared analytical photometer (manufactured by Shimadzu Corporation, product number "UV-3100PC") in accordance with JIS K7361-1-1997.

[0091] (Reflectance evaluation) The glass plates of Examples 1 to 8 and Comparative Examples 1 to 8 were evaluated for reflectance. In evaluating the reflectance, in the glass plates of Examples 1 to 8 and Comparative Examples 1 to 7, a mending tape (manufactured by 3M Japan, product number "810-3-24") was applied to the main surface opposite to the main surface on one side on which each treatment was performed, so as not to trap air bubbles, and the reflectance of the main surface on which the mending tape was not applied (the main surface on one side on which each treatment was performed) was measured. In addition, in the glass plate of Comparative Example 8, a mending tape (manufactured by 3M Japan, product number "810-3-24") was applied to the main surface on one side on which each treatment was performed, so as not to trap air bubbles, and the reflectance of the main surface on which the mending tape was not applied (the main surface on the other side) was measured. The reflectance was calculated from the average of the wavelength range of 380 nm to 780 nm. The reflectance was also measured using an ultraviolet-visible-near infrared spectrophotometer (manufactured by JASCO Corporation, product number "V-780").

[0092] (Glare evaluation) The glass plates of Examples 1 to 8 and Comparative Examples 1 to 8 were evaluated for glare (sparkle). The evaluation of glare was performed by placing the glass plates of Examples 1 to 8 and Comparative Examples 1 to 8 on a smartphone (iPhone (registered trademark) 13, manufactured by Apple Inc.), visually checking the glare on the glass plate when a green image was displayed on the smartphone, and evaluating it according to the following evaluation criteria. The glass plates of Examples 1 to 8 and Comparative Examples 1 to 7 were placed so that the main surface on one side that had been subjected to each treatment was the front side. On the other hand, the glass plate of Comparative Example 8 was placed so that the main surface on one side (untreated) was the front side. The smaller the value of the evaluation criteria for glare, the better the results.

[0093] <Glare evaluation criteria> 1: No glare observed 2: Glare is slightly noticeable 3: Glare is slightly noticeable 4: Glare is visible to some extent 5: Glare is clearly visible

[0094] (Evaluation of visibility) The glass plates of Examples 1 to 8 and Comparative Examples 1 to 8 were evaluated for visibility. The visibility was evaluated by placing the glass plates of Examples 1 to 8 and Comparative Examples 1 to 8 on a smartphone (iPhone (registered trademark) 13, manufactured by Apple Inc.) and evaluating whether the glass plates had excellent visibility based on the degree of glare, reflection, etc., according to the following evaluation criteria. The smaller the value of the visibility evaluation criteria, the better the results.

[0095] <Visibility evaluation criteria> 1: Excellent visibility so that you can clearly read the text displayed on the screen 2: There is a slight amount of glare and reflection, but visibility is fairly good. 3: Glare and reflections are a bit bothersome, and visibility is somewhat insufficient. 4: Glare, reflections, etc. interfere with viewing the image, making visibility insufficient 5: Visibility is poor due to glare and reflections that have a large impact on viewing images.

[0096] [Evaluation Results] The evaluation results are shown in Tables 3 and 4 below.

[0097] [Table 3]

[0098] [Table 4]

[0099] (Surface roughness evaluation results) As shown in Tables 3 and 4, the arithmetic mean height Sa of one main surface (treated surface) of the glass plate was within a range of 18.5 nm to 110.4 nm in Examples 1 to 8. In contrast, the arithmetic mean height Sa of one main surface (treated surface) of the glass plate was within a range of 51.1 nm to 540.9 nm in Comparative Examples 1 to 7, and the arithmetic mean height Sa of one main surface (untreated surface) of the glass plate in Comparative Example 8 was as small as 3.4 nm.

[0100] In addition, the maximum height Sz of one main surface (treated surface) of the glass plate was within a range of 1039.0 nm to 2392.9 nm in Examples 1 to 8. In contrast, the maximum height Sz of one main surface (treated surface) of the glass plate was within a range of 403.4 nm to 3961.1 nm in Comparative Examples 1 to 7, and the maximum height Sz of one main surface (untreated surface) of the glass plate in Comparative Example 8 was as small as 34.5 nm.

[0101] In addition, the skewness Ssk of one main surface (treated surface) of the glass plate was within a range of -2.0 to -0.1 in Examples 1 to 8. In contrast, the skewness Ssk of one main surface (treated surface) of the glass plate was within a range of -0.8 to 0.3 in Comparative Examples 1 to 7, and the skewness Ssk of one main surface (untreated surface) of the glass plate in Comparative Example 8 was 0, which was not a negative value.

[0102] In addition, the kurtosis Sku of one main surface (treated surface) of the glass plate was within a range of 5.9 to 19.8 in Examples 1 to 8. In contrast, the kurtosis Sku of one main surface (treated surface) of the glass plate was within a range of 2.6 to 3.5 in Comparative Examples 1 to 7, and the kurtosis Sku of one main surface (untreated surface) of the glass plate in Comparative Example 8 was as small as 2.7.

[0103] Also, in Examples 1 to 8, the maximum peak height Sp of the main surface (processed surface) on one side of the glass plate was in the range of 403.9 nm to 1083.2 nm. On the other hand, in Comparative Examples 1 to 7, the maximum peak height Sp of the main surface (processed surface) on one side of the glass plate was in the range of 166.8 nm to 2341.4 nm, and the maximum peak height Sp of the main surface (unprocessed surface) on one side of the glass plate in Comparative Example 8 was as small as 18.1 nm.

[0104] Also, in Examples 1 to 8, the maximum valley depth Sv of the main surface (processed surface) on one side of the glass plate was in the range of 635.1 nm to 1309.7 nm. On the other hand, in Comparative Examples 1 to 7, the maximum valley depth Sv of the main surface (processed surface) on one side of the glass plate was in the range of 236.5 nm to 2144.1 nm, and the maximum valley depth Sv of the main surface (unprocessed surface) on one side of the glass plate in Comparative Example 8 was as small as 16.6 nm.

[0105] In Examples 1 to 8, the maximum peak height Sp and the maximum valley depth Sv of the main surface (processed surface) on one side of the glass plate were both in the relationship of Sp < Sv. In contrast, for the glass plates of Comparative Examples 1 to 3 and 5, the relationship was Sp < Sv, but for the glass plates of Comparative Examples 4, 6, and 7, the relationship was Sp > Sv. Also, for the glass plate of Comparative Example 8, the relationship was Sp > Sv.

[0106] Also, in Examples 1 to 8, the root mean square gradient Sdq of the main surface (processed surface) on one side of the glass plate was in the range of 0.26 to 0.91. On the other hand, in Comparative Examples 1 to 7, the root mean square gradient Sdq of the main surface (processed surface) on one side of the glass plate was in the range of 0.05 to 0.24, and the root mean square gradient Sdq of the main surface (unprocessed surface) on one side of the glass plate in Comparative Example 8 was as small as 0.03.

[0107] In addition, the average length RSm1 of one main surface (treated surface) of the glass plate was within a range of 3.2 μm to 6.3 μm in Examples 1 to 8. In contrast, the average length RSm1 of one main surface (treated surface) of the glass plate was within a range of 8.9 μm to 24.1 μm in Comparative Examples 1 to 7, and the average length RSm1 of one main surface (untreated surface) of the glass plate in Comparative Example 8 was 3.1 μm.

[0108] Furthermore, in Examples 1 to 8, the ratio Sdq / RSm1 calculated from the root-mean-square gradient Sdq and the average length RSm1 of one main surface (treated surface) of the glass plate was within a range of 0.081 to 0.243. In contrast, the glass plates of Comparative Examples 1 to 7 had a ratio Sdq / RSm1 within a range of 0.003 to 0.018, and the glass plate of Comparative Example 8 had a ratio Sdq / RSm1 of 0.008.

[0109] In Examples 1 to 5 and Comparative Examples 1 to 7, the second irregularities were not formed on one main surface (treated surface) of the glass plate. In Comparative Example 8, the second irregularities were not formed on one main surface (untreated surface) of the glass plate. On the other hand, in Examples 6 to 8, the second irregularities were formed on one main surface (treated surface) of the glass plate. The maximum heights Rz of the second irregularities on one main surface (treated surface) of the glass plate in Examples 6 to 8 were within a range of 15 nm to 1000 nm. In addition, the average length RSm2 of the roughness curve elements of the second irregularities on one main surface (treated surface) of the glass plate in Examples 6 to 8 was within a range of 500 μm to 2000 μm.

[0110] (Haze measurement results) As shown in Tables 3 and 4, the haze of the glass plates of Examples 1 to 8 was within the range of 3.2% to 28.5%. In contrast, the haze of the glass plates of Comparative Examples 1 to 7 was within the range of 3.5% to 87.2%. The haze of the glass plate of Comparative Example 8 (untreated) was quite low, at 0.1%.

[0111] (Reflectance measurement results) As shown in Tables 3 and 4, the reflectances of the glass plates of Examples 1 to 8 were in the range of 0.60% to 2.80%. In contrast, the reflectances of the glass plates of Comparative Examples 1 to 7 were in the range of 0.16% to 3.94%. Moreover, the reflectance of the glass plate of Comparative Example 8 (untreated) was 4.30%.

[0112] (Glare evaluation results) As shown in Tables 3 and 4, the evaluation results for glare in the glass plates of Examples 1 to 8 were good, within the range of 1 to 2. In contrast, the evaluation results for glare in the glass plates of Comparative Examples 1 to 4 and 6 were within the range of 3 to 5, and the evaluation result for glare in the glass plates of Comparative Examples 5 and 7 was 2. Furthermore, the evaluation result for glare in the glass plate of Comparative Example 8 (untreated) was 1.

[0113] (Visibility evaluation results) As shown in Tables 3 and 4, the visibility evaluation results of the glass plates of Examples 1 to 8 were good, within a range of 1 to 2. In contrast to this, the visibility evaluation results of the glass plates of Comparative Examples 1 to 3 were within a range of 4 to 5. Moreover, the visibility evaluation result of the glass plates of Comparative Examples 4 to 7 was 3, which was inferior to Examples 1 to 8. Moreover, the visibility evaluation result of the glass plate of Comparative Example 8 (untreated) was 3.

[0114] (comprehensive evaluation) From the above results, it was confirmed that, for Examples 1 to 8, the suitable uneven shape formed on one main surface of the glass plate can suppress an increase in haze while keeping the effects of glare low, and that good results can be obtained in which discomfort is not felt even when viewing images.

[0115] On the other hand, in Comparative Examples 1 to 4 and 6, the ratio Sdq / RSm1 was small in the uneven shape formed by etching on one main surface of the glass plate, so the effect of glare was large and it was easy to feel uncomfortable when viewing the image.

[0116] In Comparative Examples 5 and 7, in the uneven shape formed by etching on one principal surface of the glass plate, the arithmetic mean height Sa was large, and the effect of glare was reduced due to the very high haze. However, the visibility of the image was reduced due to the excessively high haze, making it easy to feel discomfort.

[0117] In Comparative Example 8, the glass plate was not treated, and therefore the glare was good, but the reflectance was high, and the anti-glare performance and visibility were insufficient. [Explanation of symbols]

[0118] 1,10...Anti-glare glass plate 1a...First main surface 1b…Second main surface 2...Uneven part 3…Unprocessed part

Claims

1. A glass plate having antiglare properties, The glass plate has an uneven portion on at least a part of a main surface thereof, The uneven portion has an arithmetic mean height Sa of a contour curved surface of 15 nm or more and 300 nm or less, and a ratio (Sdq / RSm1) of a root mean square gradient Sdq of the contour curved surface to an average length RSm1 of a roughness curve element is 0.05 or more.

2. 2. The antiglare glass plate according to claim 1, wherein the irregularities have a contour curved surface with a skewness Ssk of a negative value and a contour curved surface with a kurtosis Sku of 3.6 or more.

3. 3. The anti-glare glass plate according to claim 1, wherein the irregularities have a maximum peak height Sp of the contoured curved surface and a maximum valley depth Sv of the contoured curved surface that satisfy the relationship Sp<Sv.

4. 3. The anti-glare glass plate according to claim 1, wherein the irregularities have a root-mean-square gradient Sdq of a contour curved surface of 0.25 or more.

5. 3. The anti-glare glass plate according to claim 1, wherein the irregularities have an average length RSm1 of roughness curve elements of 8.5 μm or less.

6. When the concave-convex is a first concave-convex, The uneven portion further includes a second unevenness having an average length of roughness curve elements longer than an average length RSm1 of the roughness curve elements of the first unevenness, 3. The antiglare glass plate according to claim 1, wherein the average length RSm2 of the roughness curve elements of the second irregularities is 10 μm or more.

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