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

Abstract

An embodiment of the present invention relates to a glass substrate having a specific mother composition, and having, on at least one of main surfaces, an etched surface that has 400-2000 protrusions, obtained by using image processing software SPIP manufactured by Image Metrology to shape-analyze XYZ data on the surface shape obtained by measuring a region of 285.12 μm × 213.77 μm by means of a laser microscope.

Description

[Technical field]

[0001] The present invention relates to a glass substrate for use in a display device or the like, which has reduced glare and excellent cleanability, a display device including the glass substrate, and a method for manufacturing the glass substrate.

[0002] 2. Description of the Related Art In recent years, a cover made of glass has been placed 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, when such a glass plate is installed on a display device, objects placed nearby are often reflected on the glass plate when a viewer tries to view an image displayed on the display device through the glass plate. When such reflection occurs on the glass plate, it becomes difficult for a viewer to view the displayed image, and the viewer is given an unpleasant impression.

[0004] In order to suppress such reflections, for example, anti-glare treatment has been attempted to form an uneven shape on the surface of the glass plate. Examples of anti-glare treatment include etching the surface of the glass plate (see, for example, Patent Document 1) and forming a film having an uneven shape on the surface of the glass plate (see, for example, Patent Document 2).

[0005] On the other hand, in such display devices, there are many opportunities for a person's finger or the like to touch the surface of the glass substrate that forms the cover, and when the person's finger or the like touches the surface of the glass substrate, grease or the like is likely to adhere to the surface of the glass substrate. Since the adhesion of grease or the like affects visibility, conventionally, a glass substrate that has been subjected to an anti-glare treatment and then subjected to an anti-soiling treatment has been used. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 119453 [Patent Document 2] U.S. Patent No. 8,003,194 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, the anti-glare treatment suppresses reflection, reduces reflection, and provides an anti-fouling effect, but it may also have disadvantages such as glare and reduced washability. If glare occurs on the glass substrate, it becomes difficult for a viewer to view the displayed image, and the viewer will have an unpleasant impression.

[0008] Glare becomes prominent when the roughness of the anti-glare treated surface of the glass substrate is greater than the pitch between pixels of the display device, or when the size of the surface irregularities of the glass substrate is not uniform, or when the depth of the irregularities is not uniform. As the resolution of display devices increases, the pixel size and pixel pitch are also becoming smaller, so it is expected that the glare problem of glass substrates will become more and more prominent in the future. As described above, grease and the like are easily attached to the surface of the glass substrate in display devices, and there is a problem that the anti-glare treatment tends to reduce the cleanability of grease and the like.

[0009] Therefore, an object of the present invention is to provide a glass substrate including an etched surface that suppresses glare and has excellent cleanability. [Means for solving the problem]

[0010] Means for Solving the Problems The present inventors have discovered that by etching glass having a specific composition, a glass substrate including an etched surface that suppresses glare and has excellent cleanability can be obtained, and have thus completed the present invention.

[0011] That is, the gist of the present invention is as follows. 1. The parent composition is expressed as mole percentage based on oxide. SiO2: 50-75% Al2O3: 0.1-25% B2O3: 0-10% Y2O3: 0-5% MgO: 0-20% CaO: 0-15% Li2O: 0~15% Na2O: 1-25% K2O: 0.1-20% TiO2: 0-1% ZrO2: 0-2% and A glass substrate comprising, on at least one of its main surfaces, an etched surface having 400 or more and 2,000 or less protrusions as determined by the following method: Method: A 285.12μm x 213.77μm area is measured with a laser microscope to obtain XYZ data of the surface shape. In the shape analysis of the XYZ data using the image processing software SPIP manufactured by Image Metrology, after leveling the entire surface, Particle The number of protrusions is determined when the detection threshold level is set to 50.0000 nm. 2. The average irregularity spacing RSm on the etched surface is 30 μm 2. The glass substrate according to claim 1, wherein 3. The arithmetic mean tilt angle RΔa on the etched surface is 1.50 under the condition of no cutoff value. ° 3. The glass substrate according to 1 or 2 above. 4. The glass substrate according to any one of 1 to 3 above, wherein the haze ratio of transmitted light on the etched surface is from 0.2 to 75%, as measured by a method in accordance with JIS K 7136 (2000). 5. Glare S on the etched surface, quantified by the following method: a 5. The glass substrate according to any one of 1 to 4 above, wherein the value of Method: A glass plate is placed on the display surface of a display device with a resolution of 264 ppi so that the etched surface is in contact with the display surface. A green monochrome image composed of RGB (0, 255, 0) is displayed on the display device. The sparkle value obtained by image analysis using a DM&S SMS-1000 installed above the glass plate is used as the glare S value. aThe distance d between the fixed image sensor and the glass plate is 568 mm, and the camera lens is a 23FM50SP lens with a focal length of 50 mm and an aperture of 16. The measurement is performed using the Difference Image Method (DIM), with 0 entered as the Pixel Ratio value, and the glare S a get. 6. The glass substrate according to any one of 1 to 5 above, wherein the base composition has a total content of Na2O, K2O and Li2O of less than 30% in terms of mole percentage based on oxides. 7. A display device comprising the glass substrate according to any one of 1 to 6 above. 8. A method for producing a glass substrate, comprising: at least one of the main surfaces including an etched surface having a number of protrusions of 400 or more and 2,000 or less, as determined by the following method, the number being expressed in mole percentage based on oxides: SiO2: 50-75% Al2O3: 0.1-25% B2O3: 0-10% Y2O3: 0-5% MgO: 0-20% CaO: 0-15% Li2O: 0~15% Na2O: 1-25% K2O: 0.1-20% TiO2: 0-1% ZrO2: 0-2% 13. A method for producing a glass substrate, comprising: subjecting a glass substrate containing the above compound to a frost treatment. Method: A 285.12μm x 213.77μm area is measured with a laser microscope to obtain XYZ data of the surface shape. In the shape analysis of the XYZ data using the image processing software SPIP manufactured by Image Metrology, after leveling the entire surface, Particle The number of protrusions is determined when the detection threshold level is set to 50.0000 nm. Effect of the Invention

[0012] The glass substrate according to the embodiment of the present invention has a glass matrix composition within a specific range and has surface properties within specific ranges, thereby effectively suppressing glare and exhibiting excellent cleanability. [Brief description of the drawings]

[0013]

Figure 1

Figure 2

[0014] The following describes a form for carrying out the present invention. However, the present invention is not limited to the following embodiment, and various modifications and substitutions can be made to the following embodiment without departing from the scope of the present invention.

[0015] <Glass base composition> The composition of glass can be determined simply by semi-quantitative analysis using X-ray fluorescence, but more accurately, it can be measured by wet analysis such as ICP emission spectrometry. The content of each component is expressed as mole percentage based on oxide, unless otherwise specified.

[0016] The glass substrate according to the embodiment of the present invention has a base composition, expressed in mole percentage on an oxide basis, of: SiO2: 50-75% Al2O3: 0.1-25% B2O3: 0-10% Y2O3: 0-5% MgO: 0-20% CaO: 0-15% Li2O: 0~15% Na2O: 1-25% K2O: 0.1-20% TiO2: 0-1% ZrO2: 0-2% The present invention is characterized in that it contains:

[0017] SiO2 is a component that constitutes the skeleton of glass. It also increases chemical durability and reduces the occurrence of cracks when the glass surface is scratched (indented).

[0018] The SiO2 content in the glass substrate of this embodiment is 50% or more. The SiO2 content is preferably 54% or more, 58% or more, 60% or more, 63% or more, 66% or more, and 68% or more in the following stepwise order.

[0019] On the other hand, if the SiO2 content exceeds 75%, the melting property is significantly reduced. Therefore, the SiO2 content in the glass substrate of this embodiment is 75% or less, preferably 74% or less, more preferably 73% or less, further preferably 72% or less, particularly preferably 71% or less, and most preferably 70% or less.

[0020] The glass substrate of this embodiment contains Al2O3, which increases the number of protrusions on the etched surface, suppresses glare, and improves cleaning properties. In order to improve the characteristics of the etched surface, such as increasing the number of protrusions, the content of Al2O3 is 0.1% or more, and preferably, in the following stepwise order, 0.3% or more, 0.5% or more, 0.7% or more, 0.8% or more, 0.9% or more, 1% or more, and 5% or more.

[0021] On the other hand, if the content of Al2O3 exceeds 25%, the acid resistance of the glass decreases or the devitrification temperature increases. Also, the viscosity of the glass increases and the melting property decreases. Therefore, the content of Al2O3 in the glass substrate of this embodiment is 25% or less, preferably 20% or less, more preferably 18% or less, further preferably 16% or less, and particularly preferably 14% or less.

[0022] Y2O3 is a component that improves the crushability of chemically strengthened glass and may be contained. When Y2O3 is contained in the glass substrate of the present embodiment, the content is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, particularly preferably 2% or more, and most preferably 2.5% or more.

[0023] If the Y2O3 content exceeds 5%, the glass may easily devitrify during melting, resulting in a deterioration in quality. Therefore, the Y2O3 content in the glass substrate of this embodiment is 5% or less, preferably 4% or less, and more preferably 3% or less.

[0024] MgO is a component that increases the surface compressive stress of chemically strengthened glass during chemical strengthening and improves crushability, and may be contained. When MgO is contained in the glass substrate of this embodiment, the content is preferably 3% or more, and more preferably 4% or more, 5% or more, 6% or more, 7% or more, and 8% or more in the following stepwise order.

[0025] On the other hand, if the MgO content exceeds 20%, the glass is likely to devitrify when melted. Therefore, the MgO content in the glass substrate of the present embodiment is 20% or less, preferably 15% or less, and more preferably 14% or less, 13% or less, 12% or less, 11% or less, and 10% or less in a stepwise manner.

[0026] CaO is a component that improves the melting property of glass and is used chemically in strengthening. Reinforcement CaO is a component that improves the crushability of glass and may be contained. When CaO is contained in the glass substrate of the present embodiment, the content is preferably 0.5% or more, more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more.

[0027] On the other hand, if the CaO content exceeds 15%, the ion exchange performance is reduced, so the CaO content in the glass substrate of this embodiment is set to 15% or less. The CaO content is preferably 10% or less, more preferably 9% or less, and further preferably 8% or less.

[0028] Li2O is also a component that forms surface compressive stress by ion exchange and improves the crushability of chemically strengthened glass. When performing a chemical strengthening treatment to exchange Li ions on the glass surface with Na ions, the content of Li2O in the glass substrate of this embodiment is preferably 3% or more, more preferably 4% or more, even more preferably 5% or more, particularly preferably 6% or more, and typically 7% or more.

[0029] On the other hand, if the Li2O content in the glass substrate of this embodiment exceeds 15%, the acid resistance of the glass is significantly reduced. The Li2O content is 15% or less, preferably 14% or less, more preferably 13% or less, further preferably 12% or less, and particularly preferably 11% or less.

[0030] On the other hand, when a chemical strengthening treatment is performed to exchange Na ions on the glass surface for K ions, if the Li2O content in the glass substrate of this embodiment exceeds 3%, the magnitude of the compressive stress may decrease. In this case, the Li2O content is preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, particularly preferably 0.5% or less, and most preferably substantially no Li2O is contained.

[0031] In this specification, the term "substantially free" means that the substance is not contained except for unavoidable impurities contained in raw materials, etc., that is, that the substance is not intentionally contained. Specifically, the content in the glass composition is less than 0.1 mol%.

[0032] By including Na2O, the number of protrusions on the etched surface can be increased, glare can be suppressed, and cleaning properties can be improved. It is also a component that improves the melting properties of glass, and forms a surface compressive stress layer when ion-exchanged.

[0033] From the viewpoint of improving the characteristics of the etched surface, such as increasing the number of protrusions, the Na2O content in the glass substrate of this embodiment is 1% or more, preferably 2% or more, and more preferably 3% or more.

[0034] On the other hand, if the Na2O content in the glass substrate of this embodiment exceeds 25%, the acid resistance of the glass is significantly reduced. From the viewpoint of acid resistance, the Na2O content is 25% or less, preferably 20% or less, more preferably 18% or less, further preferably 16% or less, and particularly preferably 14% or less.

[0035] The inclusion of K2O increases the number of protrusions on the etched surface, suppresses glare, and improves cleaning properties. In addition, the inclusion of K2O improves ion exchange performance.

[0036] From the viewpoint of improving the characteristics of the etched surface, such as increasing the number of protrusions, the content of K2O in the glass substrate of the present embodiment is 0.1% or more, preferably 0.5% or more, more preferably 1% or more, further preferably 2% or more, and particularly preferably 3% or more.

[0037] On the other hand, if the content of K2O exceeds 20%, the characteristics of the etched surface, such as a decrease in the number of protrusions, deteriorate, so the content of K2O in the glass substrate of this embodiment is 20% or less. The content of K2O is preferably 15% or less, more preferably 12% or less, even more preferably 10% or less, particularly preferably 8% or less, and most preferably 6% or less.

[0038] If the content of K2O exceeds the content of Na2O, the number of protrusions on the etched surface becomes insufficient, so the content of K2O in the glass substrate of this embodiment is preferably less than the content of Na2O. For example, the ratio of the content of Na2O / the content of K2O is preferably 1.1 or more, more preferably 1.5 or more, even more preferably 2 or more, particularly preferably 2.5 or more, and most preferably 3 or more.

[0039] The total content of Na2O, K2O and Li2O in the glass substrate of this embodiment (Na2O+K2O+Li2O) is preferably 30% or less, more preferably 28% or less, further preferably 26% or less, and particularly preferably 25% or less. By making Na2O+K2O+Li2O 30% or less, it is possible to suppress a decrease in RSm and improve cleaning properties.

[0040] TiO2 is a component that improves the crushability of chemically strengthened glass during chemical strengthening, and may be contained. When TiO2 is contained in the glass substrate of the present embodiment, the content is preferably 0.1% or more, more preferably 0.15% or more, and further preferably 0.2% or more.

[0041] On the other hand, if the TiO2 content exceeds 1%, the glass substrate is likely to be devitrified during melting, and the quality of the chemically strengthened glass may be deteriorated. The TiO2 content in the glass substrate of the present embodiment is 1% or less, preferably 0.8% or less, more preferably 0.5% or less, and further preferably 0.25% or less.

[0042] ZrO2 is a component that increases the surface compressive stress due to ion exchange, and has the effect of improving the crushability of glass, so it may be contained. When ZrO2 is contained in the glass substrate of this embodiment, the content is preferably 0.5% or more, and more preferably 1% or more.

[0043] On the other hand, if the ZrO2 content exceeds 2%, the glass substrate is likely to be devitrified during melting, and the quality may be deteriorated. The ZrO2 content in the glass substrate of this embodiment is 2% or less, preferably 1.8% or less, more preferably 1.6% or less, further preferably 1.4% or less, and particularly preferably 1.2% or less.

[0044] B2O3 is a component that improves the chipping resistance of glass and improves melting property. B2O3 is not essential. In the glass substrate of the present embodiment, the content of B2O3 when it is contained is preferably 0.5% or more, more preferably 1% or more, and further preferably 2% or more in order to improve melting property.

[0045] On the other hand, the content of B2O3 in the glass substrate of this embodiment is 10% or less. By making it 10% or less, the generation of striae during melting is suppressed, and the quality of the glass is less likely to deteriorate. The content of B2O3 is preferably 5% or less, more preferably 4% or less, further preferably 3% or less, and particularly preferably 1% or less. In order to increase the acid resistance, it is preferable that it is not contained.

[0046] P2O5 is a component that improves ion exchange performance and chipping resistance. The glass substrate of this embodiment does not necessarily contain P2O5, but when P2O5 is contained, the content is preferably 0.5% or more, more preferably 1% or more, and further preferably 2% or more.

[0047] On the other hand, by making the P2O5 content in the glass substrate of this embodiment 4% or less, the crushability and acid resistance of the chemically strengthened glass are improved. Therefore, the P2O5 content is preferably 4% or less, more preferably 3% or less, further preferably 2% or less, and particularly preferably 1% or less. In order to increase the acid resistance, it is preferable that no P2O5 is contained.

[0048] SrO is a component that improves the meltability of the chemically strengthened glass and improves the crushability of the chemically strengthened glass, and may be contained. When SrO is contained in the glass substrate of the present embodiment, the content is preferably 0.5% or more, more preferably 1% or more, even more preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more.

[0049] On the other hand, if the SrO content in the glass substrate of the present embodiment exceeds 20%, the ion exchange performance is significantly reduced, so that the SrO content is preferably 20% or less. The SrO content is more preferably 14% or less, and further preferably 10% or less, 8% or less, 6% or less, 3% or less, and 1% or less in the following stepwise order.

[0050] BaO is a component that improves the meltability of the chemically strengthened glass and improves the crushability of the chemically strengthened glass, and may be contained. When BaO is contained in the glass substrate of the present embodiment, the content is preferably 0.5% or more, more preferably 1% or more, even more preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more.

[0051] On the other hand, if the BaO content exceeds 15%, the ion exchange performance is significantly reduced. The BaO content in the glass substrate of the present embodiment is preferably 15% or less, and more preferably 10% or less, 8% or less, 6% or less, 3% or less, and 1% or less in a stepwise manner.

[0052] ZnO is a component that improves the melting property of glass and may be contained. When ZnO is contained in the glass substrate of the present embodiment, the content of ZnO is preferably 0.25% or more, and more preferably 0.5% or more.

[0053] On the other hand, if the ZnO content exceeds 10%, the weather resistance of the glass is significantly reduced. The ZnO content in the glass substrate of this embodiment is preferably 10% or less, more preferably 7% or less, further preferably 5% or less, particularly preferably 2% or less, and most preferably 1% or less.

[0054] La2O3 and Nb2O5 are components that improve the crushability of glass and may be contained. In the glass substrate of this embodiment, the content of each of these components when contained is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, particularly preferably 2% or more, and most preferably 2.5% or more.

[0055] On the other hand, if the content of La2O3 and Nb2O5 each exceeds 8%, the glass is likely to devitrify during melting, and the quality of the glass may deteriorate. The content of La2O3 and Nb2O5 in the glass substrate of this embodiment is preferably 8% or less, more preferably 6% or less, further preferably 5% or less, particularly preferably 4% or less, and most preferably 3% or less.

[0056] In the glass substrate of this embodiment, Ta2O5 and Gd2O3 may be contained in a small amount in order to improve the crushability of the glass. However, since the refractive index and reflectance increase, the amount is preferably 1% or less, more preferably 0.5% or less, and further preferably none is contained.

[0057] Furthermore, when the glass is colored and used, a coloring component may be added to the glass as long as it does not impede the achievement of the desired chemical strengthening properties. Suitable examples of the coloring component include Co3O4, MnO2, Fe2O3, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, TiO2, CeO2, Er2O3, and Nd2O3.

[0058] In the glass substrate of this embodiment, the content of the coloring components is preferably in the range of 7% or less in total, expressed as a mole percentage based on oxides. If it exceeds 7%, the glass is prone to devitrification, which is undesirable. This content is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less. When the visible light transmittance of the glass is prioritized, it is preferable that these components are not substantially contained.

[0059] In the glass substrate of this embodiment, SO3, chlorides, fluorides, etc. may be appropriately contained as a fining agent when melting the glass. It is preferable that As2O3 is not contained. When Sb2O3 is contained, it is preferably 0.3% or less, more preferably 0.1% or less, and most preferably not contained.

[0060] Furthermore, the glass substrate of this embodiment can be endowed with antibacterial properties by having silver ions on the surface.

[0061] Examples of the base composition of the glass substrate of the present embodiment include the following glass compositions. A glass composition containing 55-72% SiO2, 0.1-18% Al2O3, 0-4% B2O3, 0-1% Y2O3, 2-12% MgO, 0-10% CaO, 0-11% Li2O, 3-20% Na2O, 0.1-10% K2O, 0-0.2% TiO2, and 0-1.5% ZrO2.

[0062] The glass substrate of this embodiment includes an etched surface on at least one of its major surfaces. In the present invention, the term "etched surface" refers to a surface where a certain amount of glass material has been removed by a chemical method (i.e., acid etching) to obtain a specific surface texture / roughness. The etched surface of the glass substrate is characterized by its surface and optical properties.

[0063] <Surface characteristics> The surface characteristics of the etched surface of the glass substrate of this embodiment will be described below.

[0064] (Shape Count) The etched surface of the glass substrate of this embodiment has 400 or more protrusions as determined by the following method. Method: An area of ​​285.12 μm × 213.77 μm is measured with a laser microscope to obtain XYZ data of the surface shape. In a shape analysis of the XYZ data using image processing software SPIP manufactured by Image Metrology, after leveling the entire surface, Particle The number of protrusions is determined when the detection threshold level is set to 50.0000 nm.

[0065] The number of protrusions is preferably 500 or more, more preferably 600 or more, even more preferably 700 or more, and particularly preferably 800 or more. The number of protrusions is 2000 or less, preferably 1600 or less, more preferably 1400 or less, and even more preferably 1200 or less.

[0066] When the number of protrusions is 400 or more, glare can be suppressed and visibility can be improved. When the number of protrusions is 2000 or less, a decrease in RSm, which will be described later, can be suppressed and cleanability can be improved.

[0067] (RSm) The glass substrate of this embodiment has a mean irregularity spacing (RSm) value of 30 μm Preferably less than 28 μm More preferably, 26 μm The following is particularly preferably 25 μm RSm is 30 or less. μm If it is less than this, the glare S described below will occur. a This can reduce glare.

[0068] The lower limit of RSm is preferably 5 μm More than 8, more preferably μm More preferably, 12 μm More preferably, 15 μm RSm is 5 or more. μm If the amount is more than this, the cleaning properties can be improved.

[0069] The mean irregularity spacing (RSm) generally refers to the average value of the irregularity period in the roughness curve formed on the cross section of the measurement object. The mean irregularity spacing (RSm) can be calculated using a formula based on JIS-B0601 (2013).

[0070] (RΔa) The glass substrate of this embodiment has an arithmetic mean tilt angle (RΔa) of 1.50 on the etched surface without a cutoff value. ° More preferably, it is 1.60 or more. ° More preferably, 1.70 ° More preferably, 1.80 or more. ° RΔa is 1.50 or more. ° If the thickness is more than this, glare can be suppressed and visibility can be improved.

[0071] In the glass substrate of this embodiment, RΔa is preferably 15 °Less than 12, more preferably ° More preferably, 10 ° RΔa is 15 or less. ° When it is equal to or less than this, the cleaning property can be improved.

[0072] The arithmetic mean slope angle (RΔa) refers to the absolute value of the slope (angle) of the line segment connecting the start and end points of the profile curve in each section, which is divided horizontally at a constant interval ΔX, and the average of these values. RΔa is measured and calculated using a laser microscope. The measurement is performed at multiple locations, at least 10 locations, and preferably 12 locations or more.

[0073] As the measurement procedure, select line roughness analysis and perform analysis at any position. Data analysis can be performed in the horizontal or vertical direction of the measurement data. Data analysis does not include the cutoff value λs, the phase compensation high-pass filter λc, and the phase compensation low-pass filter λf.

[0074] (Ra) The glass substrate of this embodiment has an arithmetic mean roughness (Ra) of 0.02 on the etched surface. μm More preferably, it is 0.04 or more. μm More preferably, 0.06 μm That's all.

[0075] In the glass substrate of this embodiment, Ra is 0.50 μm Preferably less than or equal to 0.40 μm Less than or equal to 0.30, more preferably μm The following is the result.

[0076] In the glass substrate of this embodiment, Ra is 0.02 μm If the Ra is 0.50 or more, glare can be reduced. μm When it is equal to or less than this, the cleaning property can be improved. Ra can be calculated using the formula in accordance with JIS-B0601 (2013).

[0077] (Rz) The glass substrate of this embodiment has a maximum height (Rz) of surface roughness on the etched surface of 0.10 μm More preferably, it is 0.20 or more. μm More preferably, 0.30 μm That's all.

[0078] In the glass substrate of this embodiment, Rz is 2.50 μm Preferably less than or equal to 2.40 μm Less than 2.30, more preferably μm The following is the result.

[0079] Rz is 0.10 μm If Rz is 2.50 or more, glare can be reduced. μm If it is less than this, the cleaning ability can be improved. Rz can be calculated using the formula based on JIS-B0601 (2013).

[0080] <Optical properties> (Haze ratio) The haze ratio of the transmitted light in the visible light region of the etched surface of the glass substrate of this embodiment, measured according to JIS K 7136 (2000), is preferably 0.2% or more, more preferably 0.5% or more, and even more preferably 1% or more. The haze ratio is preferably 75% or less, more preferably 70% or less, and even more preferably 65% ​​or less. When the haze ratio is within the above range, the reflection of light can be significantly suppressed.

[0081] (Glitter S a ) In the present specification, the glare S measured by the following procedure is used as an index of glare. a Use the glare S a The glare S indicates the degree to which the light (image) from the displayed image is scattered by the surface of the glass plate when it passes through the glass plate, and the unevenness of the bright spots caused by the mutual interference of the scattered light is detected, and it has been confirmed that it shows a good correlation with the result of the observer's visual judgment of glare. For example, the glare S a Glass plates with large diameters have noticeable glare, while glass plates with large diameters have small glare.a Glass sheets with smaller diameters tend to reduce glare.

[0082] The glass substrate of this embodiment has a glare S measured on the etched surface by the following method. a is preferably 8 or less, more preferably 7 or less, further preferably 6 or less, and particularly preferably 5 or less.

[0083] Refer to Figure 1 for glare S a The measurement method for glare S is explained below. a When measuring, first prepare a display device 54 [iPad (registered trademark)-Air2; resolution 264 ppi]. The display surface of the display device may be provided with a cover for the purpose of preventing damage, etc.

[0084] Next, the sample to be measured, i.e., glass substrate 50, is placed on the display surface side of the display device. When first main surface 52, which is one of the main surfaces of glass substrate 50, includes an etched surface, glass substrate 50 is placed on the display surface side of the display device such that first main surface 52 is on the opposite side (surface luminance measuring device 75 side) of display device 54. In other words, second main surface 53, which is the other main surface, is placed on display device 54.

[0085] Next, with the display device turned on to display an image, an analyzer (SMS-1000; manufactured by Display-Messtechnik & Systeme [DM&S]) is used to perform image analysis of the degree of glare on the glass substrate 50. This results in a value of the glare S a is required.

[0086] During the measurement, it is preferable that a green monochromatic image composed of RGB (0, 255, 0) is displayed on the entire display screen of the display device 54. This is to minimize the effects of differences in appearance due to differences in display colors. The distance d between the tip of the imaging camera lens of the device and the transparent substrate having an anti-glare function is 568 mm. The Pixel Ratio value measured at this time (a value indicating how many times the pitch of one pixel of the display device corresponds to the pixel pitch of the imaging camera) is 2.45. The camera lens is a 23FM50SP lens with a focal length of 50 mm and an aperture of 16. The evaluation area ROI is set to 200 x 200. The measurement is performed using the Difference Image Method (DIM), with 0 entered as the Pixel Ratio value, and the glare S a The same measurement can also be performed using the Single Image Method (SIM), but the glare S a The absolute values ​​of are different and must be distinguished.

[0087] This glare S a It has been confirmed that the glare S has a good correlation with the observer's visual judgment of glare. a A transparent substrate with a large S a A transparent substrate with a small reflectance tends to suppress glare.

[0088] (G60) In the glass substrate of this embodiment, the specular gloss GS(60°) (hereinafter abbreviated as G60) of the 60-degree specular gloss defined in JIS Z 8741 (1997) on the etched surface is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more. G60 is preferably 140 or less, more preferably 135 or less, and even more preferably 130 or less. G60 is preferably 10 or more and 140 or less, more preferably 15 or more and 135 or less, and even more preferably 20 or more and 130 or less. By having G60 in the above range, light reflection is suppressed.

[0089] (Reflection image diffusion index value R) In this specification, the reflection image diffusiveness index value R, measured by the following procedure, is used as an index of anti-glare properties. The reflection image diffusiveness index value indicates the degree to which the reflected image of an object (e.g., lighting) placed around a glass plate matches the original object, and it has been confirmed that it shows a good correlation with the anti-glare properties judged visually by an observer. For example, a glass plate having a small reflection image diffusiveness index value R (close to 0) has poor anti-glare properties, and conversely, a glass plate having a large reflection image diffusiveness index value R (closer to 1) has good anti-glare properties.

[0090] In the glass substrate of this embodiment, the reflected image diffusion index value R on the etched surface is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more. When the reflected image diffusion index value R is in the above range, sufficient antiglare properties can be obtained.

[0091] A method for measuring the reflected image diffuseness index value R of the glass substrate 50 will be described with reference to Fig. 2. Fig. 2 shows a schematic diagram of an example of a measuring device used for measuring the reflected image diffuseness index value R.

[0092] As shown in FIG. 2, measuring device 70 has a linear light source device 71 and a surface luminance measuring instrument 75, and a sample to be measured, i.e., a glass substrate 50 having an anti-glare function (transparent substrate (or transparent substrate having an anti-glare function and having been subjected to an anti-glare treatment) 50) is placed in measuring device 70. Linear light source device 71 is composed of a light source 711 and a black flat plate 712, and light source 711 is provided in a slit-shaped opening in black flat plate 712. Glass substrate 50 has a first main surface 52 including an etched surface, and a second main surface 53. Linear light source device 71 faces glass substrate 50 and is placed in a direction perpendicular to the paper surface in FIG. 2. The surface luminance measuring device 75 is arranged in a vertical plane passing through the center in the width direction of the linear light source device 71.The focal point of surface luminance measuring instrument 75 is adjusted to the image of linear light source device 71 reflected by glass substrate 50. In other words, the surface on which the image is focused is made to coincide with black flat plate 712. Here, among the light incident from linear light source device 71, reflected by glass substrate 50, and incident on surface luminance measuring instrument 75, focusing on the light rays with equal incident angle θi and reflection angle θr (hereinafter referred to as first incident light 731 and first reflected light 732), θi=θr=5.7°.

[0093] Glass substrate 50 is disposed so that first main surface 52 faces linear light source device 71 and surface luminance measuring instrument 75. A black plate is disposed on second main surface 53 side of glass substrate 50. Therefore, light detected by surface luminance measuring instrument 75 is light reflected by glass substrate 50.

[0094] Next, the measurement method will be described. For example, when focusing on the light beams 733 and 734 with the difference between the incident angle θi and the reflection angle θr being θr-θi=0.5°, the light beam 734 represents a component scattered by the glass substrate 50 in a direction shifted by 0.5° from the regular reflection. The light beam coming from this direction is observed by the surface luminance measuring device 75 as an image of the portion where the black flat plate 712 and the virtual incident light 733-2 (a light beam incident at an angle equal to the reflection angle of the light beam 734) intersect. In other words, when the surface luminance is acquired by the surface luminance measuring device 75, an image is obtained in which the light scattered by the first main surface 52 of the glass substrate 50 spreads to the left and right of the bright line centered on the bright line corresponding to the regular reflection of the linear light source device 71. A luminance cross-sectional profile in a direction perpendicular to this bright line is extracted. Note that data may be accumulated in a direction parallel to the bright line in order to improve the measurement accuracy.

[0095] First, the luminance of the first reflected light 732 that is specularly reflected out of the light incident on the first main surface 52 of the glass substrate 50 is R1. The incident angle θi of the first incident light 731 is 5.7°, and the reflection angle θr of the first reflected light 732 is 5.7°. The angle at which the light changes due to reflection by the glass substrate 50 (transparent base 50) can be written as θr-θi, which is 0°. Since there is an error in the actual measurement, θr-θi is in the range of 0°±0.1°.

[0096] Next, the luminance of the light beams 733 and 734, whose difference between the incident angle θi and the reflection angle θr is θr-θi=0.5°, is defined as R2. This light beam represents a component scattered in a direction shifted by 0.5° from the regular reflection by the glass substrate 50 (transparent base 50). In reality, there is an error, so θr-θi=0.5°±0.1°. Similarly, the luminance of light rays 735 and 736 for which θr-θi=-0.5° is taken as R3. This light ray represents a component scattered in a direction shifted by -0.5° from the regular reflection by the glass substrate 50 (transparent base 50). In reality, there is an error, so θr-θi=-0.5°±0.1°.

[0097] Using the obtained luminance values ​​R1, R2, and R3, the reflected image diffuseness index value R of the glass substrate 50 is calculated according to the following formula (I). Reflection image diffusion index value R=(R2+R3) / (2×R1) Formula (I)

[0098] It has been confirmed that the reflected image diffusion index value R shows a good correlation with the result of visual judgment of the anti-glare property by an observer. For example, a glass substrate 50 having a small reflected image diffusion index value R (close to 0) has poor anti-glare property, and conversely, a glass substrate 50 having a large reflected image diffusion index value R (closer to 1) has good anti-glare property.

[0099] Such measurements can be performed, for example, by using an apparatus SMS-1000 manufactured by DM&S. When using this apparatus, a C1614A lens with a focal length of 16 mm and an aperture of 5.6 is used. The distance from the first main surface 52 of the transparent base 50 constituting the glass substrate 50 to the camera lens is about 300 mm, and the imaging scale is set in the range of 0.0276 to 0.0278. The slit-shaped opening formed by the black flat plate 712 of the linear light source device 71 is 101 mm x 1 mm.

[0100] <Manufacturing method> The method for manufacturing a glass substrate according to the present embodiment includes a step of forming an etching surface by frosting a glass substrate having the above-mentioned base composition. The frosting can be performed, for example, by immersing the glass substrate, which is the object to be treated, in a mixed solution of hydrofluoric acid and ammonium fluoride, and chemically treating the immersed surface.

[0101] As an example of the surface treatment carried out for the above purpose, there is a method of carrying out a frost treatment on the first main surface of a glass substrate. The frost treatment can be carried out by, for example, immersing the first main surface of the glass substrate, which is the object to be treated, in a mixed solution of hydrofluoric acid and ammonium fluoride, or a mixed solution of hydrofluoric acid and potassium fluoride, and chemically surface-treating the immersed surface. In particular, a method of carrying out a frost treatment in which the surface is chemically treated using a chemical solution such as hydrofluoric acid is preferred because microcracks are unlikely to occur on the treated surface and the mechanical strength is unlikely to decrease.

[0102] After creating the unevenness in this way, it is preferable to chemically etch the glass surface to smooth the surface shape, which can remove cracks caused by sandblasting or other processes and effectively suppress glare.

[0103] As an etching method, for example, a method of immersing a glass plate as a processing object in a processing solution mainly composed of hydrogen fluoride can be mentioned. Examples of components other than hydrogen fluoride include hydrochloric acid, nitric acid, citric acid, and sulfuric acid, among which hydrochloric acid and sulfuric acid are particularly preferable. By containing these, it is possible to suppress the alkaline component in the glass from reacting with hydrogen fluoride and causing a precipitation reaction locally, and to allow etching to proceed uniformly within the surface.

[0104] The glass plate is a glass plate formed by a float method, a down-draw method, or the like. In addition, not only a flat glass plate but also a curved glass plate may be used. The thickness of the glass plate is not particularly limited, and for example, a glass plate having a thickness of 10 mm or less can be used. The thinner the thickness, the lower the light absorption can be suppressed, which is preferable for applications where the purpose is to improve the transmittance.

[0105] The glass substrate may be a tempered glass plate. The tempered glass plate is a glass plate that has been subjected to a tempering treatment. The tempering treatment improves the strength of the glass, and for example, makes it possible to reduce the plate thickness while maintaining the strength. As a tempering treatment, a treatment for forming a compressive stress layer on the surface of the glass plate is generally known. Examples of means for forming a compressive stress layer on the surface of the glass plate include an air-cooling tempering method (physical tempering method) and a chemical tempering method.

[0106] The thickness of the glass plate to be chemically strengthened is preferably 0.1 to 3.0 mm, particularly preferably 0.3 to 1.5 mm. The physical and chemical strengthening treatments of the glass may be performed before or after forming an etched surface on the main surface of the glass plate. EXAMPLES

[0107] The present invention will be described below with reference to specific examples, but is not limited to these examples.

[0108] <Sample preparation> [Examples 1-14] The glass plate of this embodiment was manufactured by the following procedure: An unreinforced glass plate (size: 300 mm×300 mm, thickness: 1.0 mm) having the composition shown in Table 1 was used as the glass substrate.

[0109] First, an acid-resistant protective film was attached to the main surface of the glass plate on the side on which no etching surface was to be formed, and then a frost treatment was performed in the following manner to form an etching surface on the glass plate.

[0110] The glass plate was immersed in an aqueous solution of hydrofluoric acid to remove dirt adhering to the main surface of the glass plate on which the protective film was not attached, and the thickness of the glass plate was adjusted as a pre-processing step. Furthermore, the glass plate was immersed in a mixed solution of hydrofluoric acid and ammonium fluoride to perform a frost treatment on the main surface of the glass plate on which the protective film was not attached, thereby forming a large number of fine recesses on the main surface of the glass plate.

[0111] <Evaluation method> The properties of the glass plates produced in Examples 1 to 14 above were evaluated by the following methods. The results are shown in Table 1. Example 1 , example 7 to 11 are examples. 2~ Example 6 is a reference example, and Examples 12 to 14 are comparative examples. In addition, "1" in Table 1 indicates that the measurement was not performed.

[0112] (Shape Count) The surface shape of the main surface of the glass plate having an etched surface was measured with a laser microscope (Keyence Corporation, product name VK-X250) in an area of ​​285.12 μm × 213.77 μm observed with a 50x objective lens to obtain XYZ data. In the shape analysis of the XYZ data using image processing software SPIP6.4.3 manufactured by Image Metrology, after leveling the entire surface, Particle The number of protrusions detected when the detection threshold level was set at 50.0000 nm was measured.

[0113] (RSm, RΔa, Ra, Rz) The surface shape of the main surface of the glass plate having an etched surface was analyzed using a laser microscope (Keyence Corporation, product name VK-X250) with a 50x objective lens. RSm, RΔa, Ra, and Rz were obtained by analysis using a Keyence Corporation multi-file analysis application. Measurements of Ra, RSm, and Rz were calculated using a formula in accordance with JIS B 0601 (2013). Data analysis was performed without using the cutoff value λs, phase compensation type high-pass filter λc, and phase compensation type low-pass filter λf.

[0114] (Haze ratio) The haze ratio (%) of the etched surface of the glass plate was measured using a haze meter (manufactured by Suga Test Instruments Co., Ltd., product name: HZ-V3) in accordance with JIS K 7136 (2000).

[0115] (Reflection image diffusion index value R) A glass plate (100 mm x 100 mm x 1.3 mmt) was placed with the first main surface facing up, and a 101 mm-wide slit-shaped light was emitted from above it, and the brightness of the reflected light obtained was measured using a DM&S SMS-1000. At this time, a matte black plate was placed on the second main surface side to eliminate reflected light from the second main surface (backside reflection). A C1614A lens with a focal length of 16 mm was used as the camera lens with an aperture of 5.6, the distance from the first main surface of the glass plate to the camera lens was 300 mm, and the Imaging Scale was set to a range of 0.0276 to 0.0278. When the direction parallel to the thickness direction of the glass plate is set to angle φ=0°, the light is emitted from an angle φ=5.7°±0.1°, and the angle φ=-5.7° at the time of total reflection is set to the reference angle (angle α=0°). When the average luminance of the reflected light in the range of angle α=0°±0.1° is R1, the average luminance of the reflected light in the range of angle α=0.5°±0.1° is R2, and the average luminance of the reflected light in the range of angle α=-0.5°±0.1° is R3, the value calculated by the following formula (1) was taken as the reflected image diffuseness index value R. Reflection image diffusion index value R = (R2 + R3) / (2 × R1) Formula (1)

[0116] (Glitter S a ) The second main surface of the glass plate (100 mm x 100 mm x 1.6 mmt) was placed in contact with the display surface of a display device [iPad (registered trademark)-Air, manufactured by Apple Inc.] with a resolution of 264 ppi. With a green monochromatic image composed of RGB (0, 255, 0) displayed on the display device, the sparkle value obtained by image analysis using an SMS-1000 manufactured by DM&S Co., Ltd. placed above the glass plate was used as the glare S value. a The distance d between the fixed imaging element and the glass plate was 540 mm, and a 23FM50SP lens with a focal length of 50 mm and an aperture of 16 was used as the camera lens.

[0117] (G60) The specular gloss GS(60°) of the etched surface of the glass plate was measured according to JIS Z 8741 (1997). The measurement was performed using a Konica Minolta Rhopoint IQ-S.

[0118] [Table 1]

[0119] As shown in Table 1, in Examples 1 to 11, which are the embodiments of the present invention, the glass matrix composition is within the specified range, and therefore the shape count, glare S a and RSm were good, glare was effectively suppressed, and cleaning properties were excellent.

[0120] On the other hand, in Example 12, which is a comparative example, the K2O content was not within the specified range, the shape count value was outside the specified range, and the glare S a In addition, RSm was slightly higher than that of the embodiment. In addition, in Example 13, which is a comparative example, the content of Al2O3 is not within the specified range, the shape count value is outside the specified range, and the glare S a and RSm was not preferred. Furthermore, in Example 14, which is a comparative example, the total content of Na2O, K2O, and Li2O was 30% or more, and the shape count value was outside the specified range. In addition, the RSm was also lower than that of the examples, suggesting that the cleaning ability was inferior.

[0121] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. Furthermore, the components in the above-mentioned embodiments may be arbitrarily combined within the scope of the invention.

[0122] This application is based on a Japanese patent application (Patent Application No. 2020-013695) filed on January 30, 2020, the contents of which are incorporated by reference into this application. [Explanation of symbols]

[0123] 50 Glass substrate (transparent substrate) 52 First main surface 53 Second main surface 54 Display device 70 Measuring Equipment 71 Linear light source device 75 Surface Luminance Measuring Instrument 711 Light source 712 Black flat plate 731 First incident light 732 First Reflection 733, 734, 735, 736 rays 733-2 Virtual incident light θi incident angle θr Reflection angle

Claims

1. The parent composition is expressed as mole percentage based on oxides: Yes ２ :5~75% <h2 style=";text-align:left;direction:ltr">Al<h2 style=";text-align:left;direction:ltr"> ２ <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> ３ <h2 style=";text-align:left;direction:ltr"> :5~255% B ２ O ３ :0~10% Y ２ O ３ :0~5% MgO: 0 to 20% CaO: 0 to 15% Li ２ O: 0~15% Na ２ O:1~25% K ２ O: 0.1~20% TO ２ :0~1% ZrO ２ :0~2% and Na 2 O / K 2 O is 2 or more; A glass substrate comprising, on at least one of its main surfaces, an etched surface having 400 to 2,000 protrusions as determined by the following method: Method: A region of 285.12 μm × 213.77 μm is measured with a laser microscope to obtain XYZ data of the surface shape. In shape analysis of the XYZ data using image processing software SPIP manufactured by Image Metrology, after leveling the entire surface, the number of protrusions is determined when the particle detection threshold level is set to 50.0000 nm.

2. 2. The glass substrate according to claim 1, wherein a value of a mean irregularity spacing RSm on the etched surface is 30 μm or less.

3. 3. The glass substrate according to claim 1, wherein the etched surface has an arithmetic mean tilt angle R.DELTA.a of 1.50.degree. or more without a cutoff value.

4. The glass substrate as described in claim 3, wherein the arithmetic mean inclination angle RΔa on the etched surface is 1.50° or more and 12° or less, without a cutoff value.

5. 5. The glass substrate according to claim 1, wherein the haze ratio of transmitted light on the etched surface is from 0.2 to 75%, as measured by a method in accordance with JIS K 7136 (2000).

6. The glare S on the etched surface is quantified by the following method: ａ The glass substrate according to any one of claims 1 to 5, wherein the glass substrate has a refractive index of 8 or less. Method: A glass plate is placed on the display surface of a display device with a resolution of 264 ppi so that the etched surface is in contact with the display surface. A green monochrome image composed of RGB (0, 255, 0) is displayed on the display device. The sparkle value obtained by image analysis using an SMS-1000 manufactured by DM&S Co., Ltd., placed above the glass plate, is used as the glare S value. ａ The distance d between the fixed imaging element and the glass plate is 568 mm, and the camera lens is a 23FM50SP lens with a focal length of 50 mm and an aperture of 16. The measurement is performed using the Difference Image Method (DIM), 0 is input as the Pixel Ratio value, and the glare S ａ get.

7. The base composition is expressed as mole percentage on an oxide basis, and is ２ O.K. ２ O and Li ２ 7. The glass substrate according to claim 1, wherein the total content of O is less than 30%.

8. A display device comprising the glass substrate according to any one of claims 1 to 7.

9. A method for producing a glass substrate, comprising the steps of: (a) forming a glass substrate on at least one of its main surfaces with an etched surface having a number of protrusions of 400 to 2,000, both inclusive, as determined by the following method, the number being expressed in terms of mole percentage based on oxides: Yes ２ :5~75% <h2 style=";text-align:left;direction:ltr">Al<h2 style=";text-align:left;direction:ltr"> ２ <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> ３ <h2 style=";text-align:left;direction:ltr"> :5~255% B ２ O ３ :0~10% Y ２ O ３ :0~5% MgO: 0 to 20% CaO: 0 to 15% Li ２ O: 0~15% Na ２ O:1~25% K ２ O: 0.1~20% TO ２ :0~1% ZrO ２ :0~2% and A method for producing a glass substrate, comprising a step of subjecting a glass substrate having an Na 2 O / K 2 O ratio of 2 or more to a frost treatment. Method: A region of 285.12 μm × 213.77 μm is measured with a laser microscope to obtain XYZ data of the surface shape. In shape analysis of the XYZ data using image processing software SPIP manufactured by Image Metrology, after leveling the entire surface, the number of protrusions is determined when the particle detection threshold level is set to 50.0000 nm.

Images