Cover glass for a touch panel, touch panel, and method for manufacturing the cover glass for a touch panel

Abstract

This technology improves the writing experience with a pen on touch panels where pen input is performed, while also suppressing white blurring. [Solution] The cover glass of the touch panel is used for pen input. The cover glass comprises a glass plate having an uneven surface on the side facing the pen used for pen input, and a water-repellent layer formed along the uneven surface of the glass plate. The uneven surface of the glass plate has an arithmetic mean inclination angle RΔa of 5.0° or less and a core space volume Vvc of 0.6 mL / m 2 ~2.6 mL / m² 2 The water-repellent layer has a water contact angle of 90° or more.

Description

Technical Field

[0001] The present disclosure relates to a cover glass for a touch panel, a touch panel, and a method for manufacturing a cover glass for a touch panel.

Background Art

[0002] A touch panel has a display and a cover for protecting the screen of the display. The cover may have a fine uneven surface on its surface to suppress the reflection of surrounding objects (including illumination) (see, for example, Patent Document 1). The cover is a resin cover or a glass cover. The resin cover is excellent in terms of light weight and impact resistance. On the other hand, the glass cover is excellent in terms of weather resistance and abrasion resistance. When pen input is performed on the touch panel, it is preferable to use a glass cover to suppress the wear of the uneven surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The uneven surface of Patent Document 1 has a fine structure and a too smooth surface, causing the pen to slip and resulting in insufficient writing feel. The fact that the structure of the uneven surface is fine can also be understood from the fact that RSm is 6000 nm or less. RSm represents the average pitch of convex or concave.

[0005] In addition, when input is performed with a finger instead of a pen and fingerprints adhere to the uneven surface, the writing feel with a pen may change. Furthermore, the uneven surface may scatter light, resulting in so-called white blurring. White blurring refers to a phenomenon in which the display (especially a black display) becomes blurred and appears white.

[0006] One embodiment of this disclosure provides a technology for a touch panel where pen input is performed, which improves the writing feel with a pen and suppresses white blurring. [Means for solving the problem]

[0007] A cover glass for a touch panel according to one embodiment of the present disclosure is used for pen input. The cover glass comprises a glass plate having an uneven surface on the surface facing the pen used for pen input, and a water-repellent layer formed along the uneven surface of the glass plate. The uneven surface of the glass plate has an arithmetic mean inclination angle RΔa of 5.0° or less, obtained by dividing the contour curve horizontally at regular intervals ΔX, calculating the absolute value of the inclination (angle) of the line segment connecting the start and end points of the contour curve within each section, and averaging these values, and a core space volume Vvc as defined in JIS B0681-3:2019 of 0.6 mL / m 2 ~2.6 mL / m² 2 The water-repellent layer has a water contact angle (WCA) of 90° or more, as defined in JIS R3257:1999. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, in a touch panel where pen input is performed, it is possible to improve the writing feel with a pen and suppress white blurring. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of a touch panel according to one embodiment. [Figure 2] Figure 2 is a flowchart showing a method for manufacturing a cover glass according to one embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an example of a concave surface formed starting from a microcrack. [Figure 4] Figure 4 shows an example of how fingerprint stains change due to increases in WCA and Vvc. [Figure 5]Figure 5 shows an example of a combination of RΔa and Haze shown in Tables 1 to 3. [Figure 6] Figure 6 shows an example of a combination of Vvc and RΔa shown in Tables 1 to 3. [Figure 7] Figure 7 shows an example of a Vvc and WCA combination as shown in Tables 1 to 3. [Figure 8] Figure 8 shows an example of a combination of Vvc and (Vvc + Vmc) as shown in Tables 1 to 3. [Figure 9] Figure 9 shows an example of RSm and Ra combinations shown in Tables 1 to 3. [Modes for carrying out the invention]

[0010] The embodiments for implementing this disclosure will be described below with reference to the drawings. In each drawing, identical or similar components will be denoted by the same reference numeral, and their descriptions may be omitted. In the specification, the "~" indicating a numerical range means that the numbers written before and after it are included as the lower and upper limits. The numerical range includes the rounded range.

[0011] Referring to Figure 1, a touch panel 1 according to one embodiment will be described. The touch panel 1 is incorporated into portable or fixed electronic devices. Portable electronic devices include, for example, mobile phones, smartphones, e-readers, or notebook personal computers. Fixed electronic devices include, for example, desktop personal computers, digital signage, in-car displays, televisions, or interactive flat panels (IFPs).

[0012] The touch panel 1 includes, for example, a display 2 and a cover glass 3. The display 2 and the cover glass 3 are bonded together with an adhesive layer (not shown), such as OCA (Optical Clear Adhesive). The display 2 is not particularly limited, but may be, for example, a liquid crystal display, an organic EL display, or electronic paper. The display 2 has a screen protected by the cover glass 3.

[0013] The display 2 includes a touch sensor 21 inside. The touch sensor 21 detects the proximity of the pen 5 to the screen of the display 2. The touch sensor 21 may also detect the proximity of a finger instead of the pen 5. If the touch panel 1 is for in-vehicle use, the touch sensor 21 accepts input from the vehicle's occupants.

[0014] The cover glass 3 includes a glass plate 30. The glass plate 30 may be flat or curved. The thickness of the glass plate 30 is preferably 5 mm or less, and more preferably 3 mm or less. Furthermore, the thickness of the glass plate 30 is preferably 0.2 mm or more, and more preferably 0.3 mm or more.

[0015] The glass of the glass plate 30 is, for example, aluminosilicate glass, alkali aluminosilicate glass, soda-lime glass, borosilicate glass, phosphate silicate glass, alkali aluminoborosilicate glass, lead glass, alkali barium glass, or aluminoborosilicate glass. Specifically, the following glasses (i) to (v) are examples.

[0016] (i) Glass containing, in mole percent based on oxides, 50% to 80% SiO2, 0% to 26% Al2O3, 1% to 25% Na2O, 0% to 10% B2O3, 0% to 20% K2O, 0% to 20% MgO, and 0% to 15% CaO.

[0017] (ii) Glass containing, in mole percent based on oxides, 50% to 80% SiO2, 2% to 25% Al2O3, 0% to 10% Li2O, 0% to 18% Na2O, 0% to 10% K2O, 0% to 15% MgO, 0% to 5% CaO, and 0% to 5% ZrO2.

[0018] (iii) Glass containing 50% to 74% SiO2, 1% to 10% Al2O3, 6% to 14% Na2O, 3% to 11% K2O, 2% to 15% MgO, 0% to 6% CaO, and 0% to 5% ZrO2, with the total content of SiO2 and Al2O3 being 75% or less, the total content of Na2O and K2O being 12% to 25%, and the total content of MgO and CaO being 7% to 15%.

[0019] (iv) Glass containing 68% to 80% SiO2, 4% to 10% Al2O3, 5% to 15% Na2O, 0% to 1% K2O, 4% to 15% MgO, and 0% to 1% ZrO2, expressed in mole percent based on oxides.

[0020] (v) Glass containing 67% to 75% SiO2, 0% to 4% Al2O3, 7% to 15% Na2O, 1% to 9% K2O, 6% to 14% MgO, and 0% to 1.5% ZrO2, with a total content of 71% to 75% SiO2 and Al2O3, a total content of 12% to 20% Na2O and K2O, and if CaO is present, its content is less than 1%.

[0021] The glass plate 30 includes a first main surface 31 and a second main surface 32 facing the opposite direction from the first main surface 31, and is laminated on the display 2 with the second main surface 32 facing the display 2. The first main surface 31 is the surface facing the pen 5. The cover glass 3 has an uneven surface 31a on the first main surface 31. The uneven surface 31a only needs to be formed in the area where input by the pen 5 is performed, and only needs to be formed on at least a part of the first main surface 31.

[0022] The uneven surface 31a is formed by, for example, at least one of the following processes selected from frosting, etching, and blasting of the surface of the glass plate 30. The uneven surface 31a can disperse the direction of light reflection and suppress reflections of surrounding objects (including lighting). Preferably, the uneven surface 31a is formed on the first main surface 31 but not on the second main surface 32. Preferably, the second main surface 32 is protected by a mask when forming the uneven surface 31a on the first main surface 31.

[0023] For the uneven surface 31a, it is preferable that the arithmetic mean slope angle RΔa, obtained by dividing the contour curve horizontally at regular intervals ΔX, calculating the absolute value of the slope (angle) of the line segment connecting the start and end points of the contour curve within each section, and averaging these values, is 5.0° or less. The line segment slope (angle) is measured at at least 20 locations. As for the measurement procedure, line roughness analysis is selected, and data analysis is performed at arbitrary positions. In the data analysis, the cutoff value λs, phase-compensated high-pass filter λc, and phase-compensated low-pass filter λf are not used.

[0024] If the arithmetic mean tilt angle RΔa of the uneven surface 31a is 5.0° or less, light scattering hardly occurs, and therefore, blurring is hardly produced. The RΔa of the uneven surface 31a is more preferably 4.0° or less. Furthermore, the RΔa of the uneven surface 31a is 1.0° or more. The RΔa of the uneven surface 31a is correlated with the haze value of the cover glass 3, which will be described later. The smaller the RΔa of the uneven surface 31a, the smaller the haze value of the cover glass 3.

[0025] The cover glass 3 preferably has a haze value of 45% or less as specified in JIS K7136:2000. The haze value is measured using a commercially available measuring device. For example, the Suga Test Instruments HZ-V3 haze meter is used. The haze value is measured using a C light source. The haze value is determined as the percentage of transmitted light that is deflected by 2.5° or more from the incident light due to forward scattering, among the transmitted light that passes through the cover glass 3 in the thickness direction.

[0026] The haze value of the cover glass 3 is preferably 0% or more and 45% or less. If the haze value of the cover glass 3 is 45% or less, the clarity of the transmitted image is good. The haze value of the cover glass 3 is more preferably 35% or less. The haze value of the cover glass 3 may be 0% or more, but is more preferably 5% or more, and even more preferably 10% or more.

[0027] The uneven surface 31a has a core space volume Vvc of 0.6 mL / m² as defined in JIS B0681-3:2019. 2 ~2.6 mL / m² 2 It is preferable that the Vvc of the uneven surface 31a is 0.6 mL / m². 2 If the above conditions are met, the effect of the water-repellent layer 33, described later, can be maintained for a long period of time.

[0028] The water-repellent layer 33 is formed along the uneven surface 31a. Therefore, the water-repellent layer 33 has a surface roughness similar to that of the uneven surface 31a of the glass plate 30. The water-repellent layer 33 forms the contact surface 33a of the cover glass 3 with the pen 5 and the finger. Hereinafter, the contact surface 33a of the cover glass 3 with the pen 5 and the finger may be simply referred to as the touch surface.

[0029] The water-repellent layer 33 preferably has a water contact angle (WCA) of 90° or more, as specified in JIS R3257:1999. The WCA of the water-repellent layer 33 is determined by measuring the contact angle of approximately 2 μL of pure water placed on the touch surface of the water-repellent layer 33. For measuring the contact angle of pure water, for example, a contact angle measuring device (DMo-702, manufactured by Kyowa Interface Science Co., Ltd.) is used. The contact angle of pure water is measured at five locations, and the average value is determined as the WCA.

[0030] As shown in Figure 4, if the water contact angle WCA of the water-repellent layer 33 is large (specifically, for example, 90° or more), fingerprint smudges 40 are more easily repelled, the convex parts of the touch surface are more easily exposed, and the cover glass 3 can provide appropriate dynamic friction and vibration to the pen 5. It is more preferable that the WCA of the water-repellent layer 33 be 100° or more. However, the WCA of the water-repellent layer 33 may be 130° or less.

[0031] As shown in Fig. 4, if the Vvc of the uneven surface 31a is large (specifically, for example, 0.6 mL / m 2 or more), the concave part of the touch surface is wide and deep, and even if fingerprint smudges 40 accumulate, the convex part of the touch surface is likely to be exposed. Therefore, over a long period of time, the cover glass 3 can apply appropriate dynamic friction and appropriate vibration to the pen 5. The Vvc of the uneven surface 31a is preferably 0.6 mL / m 2 ~2.6 mL / m 2 , and more preferably 0.8 mL / m 2 ~2.4 mL / m 2 .

[0032] Incidentally, the larger the Vvc of the uneven surface 31a, the more difficult it is for the pen 5 to slip. Also, when there is a water-repellent layer 33, the pen 5 is easier to slide than when there is no water-repellent layer 33. If the Vvc of the uneven surface 31a is 0.6 mL / m 2 ~2.6 mL / m 2 and there is a water-repellent layer 33, an appropriate ease of sliding of the pen 5 can be ensured, and the writing feel with the pen 5 is good.

[0033] The uneven surface 31a preferably has a sum (Vvc + Vmc) of the core part space volume Vvc and the core part solid volume Vmc defined in JIS B0681-3:2019 of 1.2 mL / m 2 ~4.9 mL / m 2 . If the (Vvc + Vmc) of the uneven surface 31a is 1.2 mL / m 2 or more, the concave part of the touch surface is wide and deep, and even if fingerprint smudges 40 accumulate, the convex part of the touch surface is likely to be exposed. Therefore, over a long period of time, the cover glass 3 can apply appropriate dynamic friction and appropriate vibration to the pen 5. The (Vvc + Vmc) of the uneven surface 31a is more preferably 1.7 mL / m 2 ~4.2 mL / m 2 .

[0034] The uneven surface 31a preferably has an average length RSm of roughness curve elements specified in JIS B0601:2001 of 80 μm to 210 μm. RSm represents the average pitch of the convex or concave areas. The larger the RSm, the larger the average pitch of the convex or concave areas. If the RSm of the uneven surface 31a is 80 μm or more, the concave areas of the touch surface are wide, and even if fingerprint stains 40 accumulate, the convex areas of the touch surface are easily exposed. The RSm of the uneven surface 31a is more preferably 100 μm to 190 μm.

[0035] The uneven surface 31a preferably has an arithmetic mean roughness Ra of 0.4 μm to 2.0 μm as defined in JIS B0601:2001. Ra represents the average height difference between the convex and concave surfaces. The larger the Ra, the greater the average height difference between the convex and concave surfaces. If the Ra of the uneven surface 31a is 0.4 μm or more, the concave parts of the touch surface are deep, and even if fingerprint stains 40 accumulate, the convex parts of the touch surface are easily exposed. The Ra of the uneven surface 31a is more preferably 0.6 μm to 1.6 μm.

[0036] The uneven surface 31a has a (RSm / √Ra) of 90 μm. 0.5 ~180μm 0.5 And (RSm × √Ra) is 50 μm 1.5 ~250μm 1.5 It is preferable that (RSm / √Ra) is the value obtained by dividing RSm by the square root of Ra. (RSm×√Ra) is the value obtained by multiplying RSm by the square root of Ra.

[0037] The (RSm / √Ra) of the uneven surface 31a is 90 μm 0.5 ~180μm 0.5 Furthermore, the (RSm × √Ra) of the uneven surface 31a is 50 μm 1.5 ~250μm 1.5 Therefore, the cover glass 3 can provide the pen 5 with appropriate dynamic friction and vibration. The (RSm / √Ra) of the uneven surface 31a is 90 μm. 0.5 ~160μm 0.5 It is more preferable that the (RSm × √Ra) of the uneven surface 31a is 110 μm. 1.5 ~250μm 1.5 It is preferable that it be so.

[0038] The cover glass 3 includes a water-repellent layer 33. The water-repellent layer 33 is formed along the uneven surface 31a of the glass plate 30. Therefore, the water-repellent layer 33 has a surface roughness similar to that of the uneven surface 31a of the glass plate 30. The water-repellent layer 33 forms the contact surface 33a (touch surface) of the cover glass 3 with the pen 5 and the finger. The touch surface preferably satisfies at least the requirements of (1), (2), and (3). (1) The arithmetic mean slope angle RΔa is 5.0° or less. (2) The water contact angle WCA is 90° or greater. (3) Core space volume Vvc is 0.6 mL / m 2 ~2.6 mL / m² 2 That is the case.

[0039] If the touch surface satisfies requirement (1), there will be almost no light scattering, and therefore almost no white blurring. If the touch surface satisfies requirement (2), fingerprints 40 will be easily repelled, the raised parts of the touch surface will be easily exposed, and the cover glass 3 will be able to provide appropriate dynamic friction and appropriate vibration to the pen 5. If the touch surface satisfies requirement (3), the cover glass 3 will be able to provide appropriate dynamic friction and appropriate vibration to the pen 5 over a long period of time.

[0040] The RΔa of the touch surface is more preferably 4.0° or less. However, it is preferable that the RΔa of the touch surface is 1.0° or more. Furthermore, the Vvc of the touch surface is 0.8 mL / m². 2 ~2.4 mL / m² 2 It is more preferable that the WCA of the touch surface is 100° or more. However, the WCA of the touch surface may be 130° or less.

[0041] The (Vvc + Vmc) ratio of the touch surface is 1.2 mL / m². 2 ~4.9 mL / m² 2 It is preferable that the (Vvc + Vmc) of the touch surface be 1.2 mL / m². 2As a result, the recesses on the touch surface are wide and deep, and even if fingerprints 40 accumulate, the raised parts of the touch surface are easily exposed. Therefore, the cover glass 3 can provide appropriate dynamic friction and vibration to the pen 5 over a long period of time. The (Vvc + Vmc) of the touch surface is 1.7 mL / m². 2 ~4.2 mL / m² 2 It is preferable that it be so.

[0042] The RSm of the touch surface is preferably 80 μm to 210 μm. RSm represents the average pitch of the convex or concave areas. The larger the RSm, the larger the average pitch of the convex or concave areas. If the RSm of the touch surface is 80 μm or more, the concave areas of the touch surface are wide, and even if fingerprint stains 40 accumulate, the convex areas of the touch surface are easily exposed. The RSm of the touch surface is more preferably 100 μm to 190 μm.

[0043] The Ra of the touch surface is preferably 0.4 μm to 2.0 μm. Ra represents the average height difference between convex and concave areas. The larger the Ra, the greater the average height difference between convex and concave areas. If the Ra of the touch surface is 0.4 μm or more, the concave areas of the touch surface are deep, and even if fingerprint smudges 40 accumulate, the convex areas of the touch surface are easily exposed. The Ra of the touch surface is more preferably 0.6 μm to 1.6 μm.

[0044] The touch surface has an (RSm / √Ra) of 90 μm. 0.5 ~180μm 0.5 And (RSm × √Ra) is 50 μm 1.5 ~250μm 1.5 It is preferable that the cover glass 3 can provide the pen 5 with appropriate dynamic friction and appropriate vibration. The (RSm / √Ra) of the touch surface is 90 μm. 0.5 ~160μm 0.5 It is more preferable that the (RSm × √Ra) of the touch surface be 110 μm. 1.5 ~250μm 1.5 It is preferable that it be so.

[0045] From the perspective of water repellency, the water-repellent layer 33 has the chemical formula Rf 4-n SiX nIt is preferable that the compound is represented by (n is an integer from 1 to 3). Rf has 4 or more carbon atoms and Rf includes at least one selected from perfluoroalkyl groups, fluorine-containing ether groups, alkyl groups, and silicones. X includes a hydrolyzable group. Hydrolyzable groups include, for example, alkoxy groups, acyloxy groups, ketoxime groups, alkenyloxy groups, aminooxy groups, amide groups, isocyanate groups, or halogen atoms. From the viewpoint of balancing the chemical stability of the compound and the ease of hydrolysis, alkoxy groups, isocyanate groups, or halogen atoms are preferred. As for alkoxy groups, alkoxy groups with 1 to 4 carbon atoms are preferred, and methoxy groups or ethoxy groups are more preferred. As for halogen atoms, chlorine atoms are preferred. When multiple Xs are present in the formula, the multiple Xs may be the same or different, but it is preferable that they be the same from the viewpoint of the availability of raw materials.

[0046] The thickness of the water-repellent layer 33 is not particularly limited as long as it is a thickness that can impart good water repellency to the water-repellent film. From an economic standpoint, the thickness of the water-repellent layer 33 is preferably 50 nm or less. The lower limit of the thickness of the water-repellent layer 33 is the thickness of the monolayer.

[0047] Although not shown in the figures, the cover glass 3 may have an anti-reflective coating. The anti-reflective coating is formed, for example, between the glass plate 30 and the water-repellent layer 33. The anti-reflective coating is not particularly limited, but it is preferably made up of alternating layers of low refractive index and high refractive index, and the outermost layer is preferably an SiO2 layer.

[0048] Referring to Figure 2, a method for manufacturing a cover glass 3 according to one embodiment will be described. The method for manufacturing the cover glass 3 includes obtaining an uneven surface 31a by performing a blast treatment (step S101) and a wet etching treatment (step S102) in that order on at least a portion of the first main surface 31 of the glass plate 30.

[0049] Step S101 preferably includes wet blasting on at least a portion of the first main surface 31 of the glass plate 30. Wet blasting is a process in which a slurry containing particles is ejected from a nozzle by gas pressure and impacts the object, thereby forming minute cracks (microcracks) in the object. Alternatively, dry blasting may be performed instead of wet blasting.

[0050] The slurry contains particles, as described later, and a dispersion medium. Examples of the dispersion medium include water, a water-soluble organic solvent, or a mixture of water and a water-soluble organic solvent. Examples of water-soluble organic solvents include lower alcohols or ketones. Specific examples of lower alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, or tert-butanol. An example of a ketone is acetone.

[0051] Furthermore, the slurry may contain a dispersion aid. Examples of dispersion aids include carboxymethylcellulose, polyacrylic acid derivatives or salts thereof, polycarboxylic acid derivatives or salts thereof, or polyurea urethane. Specific examples of polyacrylic acid derivatives or salts thereof include polyacrylic acid, ammonium polyacrylate salt, sodium polyacrylate salt, polyacrylamide, acrylic acid ester / acrylate copolymer, acrylamide / acrylate copolymer, or copolymer of acrylic acid ester / acrylamide / acrylate. Specific examples of polycarboxylic acid derivatives or salts thereof include ammonium polycarboxylate salt or sodium polycarboxylate salt. The proportion of the dispersion aid in the slurry is preferably 0.03% by mass or more and 2.0% by mass or less.

[0052] From the viewpoint of processability, the particles contained in the slurry are preferably inorganic particles that have a higher Mohs hardness than glass and are not spherical. The material of the inorganic particles may be metal (including alloys) or inorganic compounds. The inorganic compounds may be metallic compounds or non-metallic compounds. Examples of metals include stainless steel, zinc, or copper. Examples of inorganic compounds include silica, glass, garnet, zirconia, alumina, silicon carbide, boron carbide, or CO2 (dry ice). Among these, alumina is preferred. Commercially available particles can be used for the slurry. An example of a commercially available product is white alumina manufactured by Fujimi Incorporated.

[0053] From the viewpoint of productivity, the particle concentration in the slurry is preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. On the other hand, from the viewpoint of slurry fluidity, the particle concentration in the slurry is preferably 30% by mass or less, and more preferably 10% by mass or less.

[0054] As shown in Figure 3, the wet blasting process forms microcracks 311 on at least a portion of the first main surface 31. Subsequently, in step S102, described later, a concave curved surface 312 can be formed by isotropically etching the glass starting from the microcracks 311, as shown in Figure 3. In Figure 3, the multiple dashed lines indicate the change in the surface shape of the glass over time. When the glass is etched isotropically, the depth H of the concave curved surface 312 becomes approximately the same as the depth of the microcracks 311.

[0055] The depth of the microcracks 311 varies depending on the particle size d, etc. The larger the particle size d, the greater the impact on the particle, and the deeper the microcracks 311 become. The greater the depth of the microcracks 311, the larger the area S of the concave surface 312 in a plan view. Also, the greater the depth of the microcracks 311, the larger the depth H of the concave surface 312 becomes.

[0056] The particles contained in the slurry have an average value of particle size d.AVE (Hereafter, average particle diameter d AVE Also called.) Preferably, the particle size is 13 μm or larger. Average particle size d AVE If the average particle size is 13 μm or larger, Vvc, RSm, and Ra can be adjusted to an appropriate range. AVE The average particle size d is more preferably 18 μm or larger, and even more preferably 24 μm or larger. AVE The particle size is preferably 60 μm or less.

[0057] The particle size distribution of particles contained in the slurry is measured, for example, using the Multisizer 4e, an electrical resistance particle size distribution analyzer manufactured by Beckman Coulter. The particle size distribution obtained using the above particle size distribution analyzer is based on the so-called "Coulter principle," which directly detects the change in impedance caused by the passage of individual particles in the electrolyte solution to the measurement site, measures the particle size of each individual particle as a spherical equivalent particle size, and then organizes the number distribution as an integrated histogram (or integrated frequency curve) with particle size on the x-axis and number (frequency) on the y-axis. Average particle size d AVE This is calculated as the so-called arithmetic mean diameter, according to the distribution of the number of elements.

[0058] Step S102 includes performing a wet etching treatment on at least a portion of the first main surface 31 of the glass plate 30. The wet etching treatment is a process in which an etching solution containing an acid or alkali is supplied to the first main surface 31 of the glass plate 30 to form a concave curved surface 312 starting from microcracks 311. The method of supplying the etching solution may be a dip method in which the glass plate is immersed in the etching solution, or a spray method in which the etching solution is applied to the glass plate. Compared to dry etching, the wet etching treatment can etch the glass isotropically.

[0059] The etching solution is, for example, a solution containing an acid. The acid concentration in the etching solution is preferably 1 to 15% by mass, and particularly preferably 3 to 10% by mass. As the acid, for example, hydrogen fluoride is used. A combination of hydrogen fluoride and hydrogen chloride may also be used.

[0060] If the etching solution is an acid-containing solution, it is preferable to etch at a temperature of 10°C to 40°C, preferably 15°C to 35°C, for 2 minutes to 1 hour.

[0061] When the etching solution is an acid-containing solution, the etching rate is preferably 0.5 μm / min or more, more preferably 1.0 μm / min or more, and even more preferably 2.0 μm / min or more, from the viewpoint of ensuring a sufficient anti-glare effect. The etching rate is preferably 20 μm / min or less.

[0062] The etching solution may be a solution containing alkali. The alkali concentration in the etching solution is preferably 1% to 50% by mass, and more preferably 3% to 50% by mass. As the alkali, at least one base selected from sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate can be used. These bases may be used individually or in combination.

[0063] The etching solution preferably contains a chelating agent in addition to the alkali. The chelating agent suppresses the recrystallization of the glass by forming a chelate complex with the metal ions of the glass dissolved in the etching solution. The chelating agent content in the etching solution is preferably 0.1 mol / L or more and 0.5 mol / L or less. Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA), citric acid, gluconic acid, succinic acid, oxalic acid, tartaric acid, or hydroxyethylidene diphosphinic acid (HEDP).

[0064] If the etching solution is an alkaline solution, it is preferable to etch at a temperature of 65°C to 150°C, preferably 80°C to 150°C, for 20 minutes to 40 hours.

[0065] When the etching solution is an alkali-containing solution, the etching rate is preferably 0.05 μm / min or more, more preferably 0.10 μm / min or more, and even more preferably 0.15 μm / min or more, from the viewpoint of ensuring a sufficient anti-glare effect. The etching rate is preferably 1.50 μm / min or less.

[0066] The method for manufacturing the cover glass 3 includes obtaining a water-repellent layer 33 by performing a water-repellent treatment (step S103) on at least a portion of the uneven surface 31a of the glass plate 30. The water-repellent treatment may be performed by a dry method or a wet method. In the dry method, a silane coupling agent is formed by a film formation process such as vapor deposition. Before this treatment, the glass plate 30 may be pre-treated as needed. Heat treatment and humidification treatment may also be performed to improve the adhesion of the coating. On the other hand, in the wet method, the silane coupling agent can be coated by applying a solution containing the silane coupling agent to the glass plate 30 and then drying the solution. Before this treatment, the glass plate 30 may be pre-treated as needed. Heat treatment and humidification treatment may also be performed to improve the adhesion of the coating.

[0067] The method for manufacturing the cover glass 3 may include processes other than steps S101 to S103. For example, after step S102 and before step S103, the glass plate 30 may be chemically strengthened. Chemical strengthening is a process that forms a compressive stress layer on the glass surface by ion exchange at a temperature below the glass transition temperature. The compressive stress layer is formed by exchanging alkali metal ions with small ionic radii contained in the glass for alkali ions with larger ionic radii. [Examples]

[0068] The experimental data is described below. Examples 1 to 6 below are comparative examples, and Examples 7 to 20 are examples. The method for manufacturing the cover glass, mainly for Example 8, will be described below. In Examples 1 to 7 and Examples 9 to 20, the cover glass was manufactured under the same conditions as in Example 8, except for the conditions listed in Tables 1 to 3, so the explanation of the method for manufacturing the cover glass will be omitted. In Example 20, dry blasting was performed instead of wet blasting. The conditions for dry blasting in Example 20 will be described later.

[0069] [Example 8] In Example 8, a cover glass was fabricated by applying wet blasting, wet etching, and water-repellent treatment to the first main surface of a glass plate in that order. The glass plate used was AGC Inc., product name: DragonTrail (registered trademark). The glass plate dimensions were 100mm x 100mm and its thickness was 0.55mm.

[0070] For the wet blasting process, a wet blasting apparatus (manufactured by Macoh Corporation, apparatus name: Jr.TypeII) was used. The slurry was prepared by mixing ceramic particles, a dispersion aid, and water as the dispersion medium. The ceramic particle content (slurry concentration) in the entire slurry was 0.10% by weight. The ceramic particles had an average particle size of d AVE The particles were 26.4 μm white alumina particles. The slurry injection pressure (gas pressure) was 0.30 MPa, the projection distance (distance between the nozzle and the glass plate) was 30 mm, the nozzle scanning speed was 200 mm / sec, and the number of nozzle scans was 12. The slurry was injected together with compressed air. Gas pressure refers to the pressure of the compressed air. After the wet blasting treatment and before the wet etching treatment, the surface was washed with pure water and dried.

[0071] In the wet etching process, the glass plate was immersed in an etching solution at 36°C for 1110 seconds to etch the first main surface of the glass plate to a depth of 120.0 μm. The second main surface of the glass plate was protected with a pre-laid acid-resistant protective film. The etching solution was an aqueous solution containing 5% by mass of hydrogen fluoride and 5% by mass of hydrogen chloride. After the wet etching process, the protective film was removed. No chemical strengthening treatment was performed before the water-repellent treatment.

[0072] In the water-repellent treatment, a water-repellent agent was applied to the glass plate and dried. Water-repellent agent D was used. Water-repellent agent D is manufactured by Nikka Chemical Co., Ltd. and its trade name is SOILNON AF-800 (Rf has 4 or more carbon atoms and Rf contains a fluorine-containing ether group). In Tables 1 to 3, the other water-repellent agents A to C and E to G are as follows. Also, as shown in Table 3, in Examples 16 and 17, a mixture of water-repellent agent E and water-repellent agent G was used. The ratios shown in Table 3 are the ratio of the number of Si atoms contained in water-repellent agent E and water-repellent agent G, respectively.

[0073] Water repellent A is trimethoxymethylsilane manufactured by Junsei Chemical Co., Ltd. (Rf has fewer than 4 carbon atoms and Rf contains an alkyl group). Water repellent B is trimethoxy(3,3,3-trifluoropropyl)silane manufactured by Tokyo Chemical Industry Co., Ltd. (Rf has fewer than 4 carbon atoms and Rf contains a perfluoroalkyl group). Water repellent C is product name: Afluid S-550 manufactured by AGC Inc. (Rf has 4 or more carbon atoms and Rf contains a fluorine-containing ether group). Water repellent E is octadecyltrimethoxysilane manufactured by Tokyo Chemical Industry Co., Ltd. (Rf has 4 or more carbon atoms and Rf contains an alkyl group). Water repellent F is trichloro(1H,1H,2H,2H-tridecafluoro-n-octyl)silane manufactured by Tokyo Chemical Industry Co., Ltd. (Rf has 4 or more carbon atoms and Rf contains a perfluoroalkyl group). Water repellent agent G is manufactured by Shin-Etsu Chemical Co., Ltd. and its product name is X-22-1968 (Rf has 4 or more carbon atoms and Rf contains silicone).

[0074] In Example 20, dry blasting was performed instead of wet blasting. The ceramic particles had an average particle size of d AVE The material used was 30.9 μm white alumina. The spray pressure (gas pressure) was 0.50 MPa, the projection distance (distance between the nozzle and the glass plate) was 60 mm, and the surface damage rate after blasting was approximately 50%. The ceramic particles were sprayed together with compressed air. Gas pressure refers to the pressure of the compressed air. After dry blasting and before wet etching, the surface was washed with pure water and dried.

[0075] [summary] Tables 1 to 3 and Figures 5 to 9 show the evaluation results for Examples 1 to 20. In Figures 5 to 9, the range indicated by the thick dashed line is the preferred range, and the range indicated by the thick solid line is the more preferred range.

[0076] [Table 1]

[0077] [Table 2]

[0078] [Table 3]

[0079] Vvc, Vmc, RSm, Ra, and RΔa were measured using a laser microscope (VK-X250, Keyence Corporation) after wet etching and before water-repellent treatment. The number of acquired data points was 1024 × 768 pixels, the measurement area was 285 μm × 214 μm, ΔX was 278 nm / pixel, and line roughness was measured at more than 20 locations in the measurement area. Furthermore, when Vvc, Vmc, RSm, and Ra were measured after water-repellent treatment, the values ​​were almost the same as those measured before water-repellent treatment.

[0080] "White blur" was classified into three stages based on the haze value of cover glass 3 (labeled "Haze" in Tables 1 to 3). Specifically, a haze value of 35% or less was marked "○", a haze value greater than 35% but 45% or less was marked "△", and a haze value greater than 45% was marked "×".

[0081] "Writing feel" refers to the writing experience when using a pen without fingerprints on the touch surface. It was classified into three levels based on the results of a sensitivity test in which all evaluators (10 people) evaluated it on a three-point scale (Good, Fair, Poor). Specifically, if 80% or more of the evaluators rated it as "Good," it was rated as "○." If 80% or more of the evaluators did not rated it as "Good," but 80% or more of the evaluators rated it as either "Good" or "Fair," it was rated as "△." All other cases were rated as "×."

[0082] "Change in writing feel" refers to the change in writing feel between a state where no fingerprints are present on the touch surface and a state where fingerprints are present on the touch surface. This was classified into three stages based on the results of a sensitivity test in which all evaluators (10 people) evaluated it on a three-point scale (present, slight, absent). Specifically, if 80% or more of the evaluators evaluated it as "absent," it was classified as "○," if 80% or more of the evaluators did not evaluate it as "absent," but 80% or more of the evaluators evaluated it as either "absent" or "slight," it was classified as "△," and all other cases were classified as "×."

[0083] As shown in Tables 1 to 3, according to Examples 7 to 20, unlike Examples 1 to 6, (1) RΔa is 5.0° or less, (2) WCA is 90° or more, and (3) Vvc is 0.6 mL / m². 2 ~2.6 mL / m² 2 Therefore, according to Examples 7 to 20, the evaluations for "white blur," "writing feel," and "change in writing feel" were all "△" or "〇."

[0084] In Example 1, Vvc is 0.6 mL / m². 2Since the value was less than 90° and the WCA was less than 90°, the evaluation of "writing feel" was "○", but the evaluation of "change in writing feel" was "×". In Example 2, Vvc was 0.6 mL / m² 2 ~2.6 mL / m² 2 Furthermore, since the WCA was less than 90°, pen 5 was not slippery, resulting in a "writing feel" rating of "×" and a "change in writing feel" rating of "×". In Examples 3 and 4, Vvc was 0.6 mL / m². 2 ~2.6 mL / m² 2 Furthermore, since the WCA was less than 90°, the evaluation of "writing feel" was "○", but the evaluation of "change in writing feel" was "×". In Example 5, Vvc was 0.6 mL / m² 2 Since the value was less than 90° and the WCA was 90° or greater, Pen 5 was slippery, resulting in a "×" rating for "writing feel" and a "△" rating for "change in writing feel".

[0085] The following additional information is disclosed regarding the above embodiments, etc. [Note 1] A cover glass for a touch panel where pen input is performed, A glass plate having an uneven surface on the side facing the pen used for pen input, A water-repellent layer formed along the uneven surface of the glass plate, It has, The uneven surface of the glass plate is such that the contour curve is divided horizontally at regular intervals ΔX, the absolute value of the slope (angle) of the line segment connecting the start and end points of the contour curve within each section is determined, and the arithmetic mean slope angle RΔa obtained by averaging these values ​​is 5.0° or less, and the core space volume Vvc as defined in JIS B0681-3:2019 is 0.6 mL / m². 2 ~2.6 mL / m² 2 And, The water-repellent layer is a cover glass for a touch panel, having a water contact angle (WCA) of 90° or more as defined in JIS R3257:1999. [Note 2] The uneven surface of the glass plate has a core volume of 1.2 mL / m², where the sum of the core spatial volume Vvc and the core physical volume Vmc is 1.2 mL / m², as defined in JIS B0681-3:2019. 2 ~4.9 mL / m²2 This refers to the cover glass of the touch panel as described in Appendix 1. [Note 3] The uneven surface of the glass plate is a cover glass for a touch panel as described in Appendix 1 or 2, wherein the average length RSm of the roughness curve elements specified in JIS B0601:2001 is 80 μm to 210 μm, and the arithmetic mean roughness Ra specified in JIS B0601:2001 is 0.4 μm to 2.0 μm. [Note 4] The water-repellent layer has the chemical formula Rf 4-n SiX n A cover glass for a touch panel according to any one of the appendices 1 to 3, comprising a compound represented by (n is an integer from 1 to 3), wherein Rf has 4 or more carbon atoms and Rf comprises at least one selected from perfluoroalkyl groups, fluorine-containing ether groups, alkyl groups, and silicones, and X comprises at least one selected from halogens and hydrolyzable groups. [Note 5] A display comprising a cover glass as described in any one of the appendices 1 to 4, and a screen protected by the cover glass, The display is a touch panel having a touch sensor that detects the proximity of a pen to the screen of the display. [Note 6] A method for manufacturing the cover glass of a touch panel on which pen input is performed, A process to form an uneven surface on the surface of the glass plate facing the pen used for pen input by performing blast treatment and wet etching treatment in this order, A step of forming a water-repellent layer along the uneven surface of the glass plate, It has, The uneven surface of the glass plate is such that the contour curve is divided horizontally at regular intervals ΔX, the absolute value of the slope (angle) of the line segment connecting the start and end points of the contour curve within each section is determined, and the arithmetic mean slope angle RΔa obtained by averaging these values ​​is 5.0° or less, and the core space volume Vvc as defined in JIS B0681-3:2019 is 0.6 mL / m². 2 ~2.6 mL / m² 2 And, The water-repellent layer has a water contact angle (WCA) of 90° or more as defined in JIS R3257:1999, as a method for manufacturing a cover glass for a touch panel.

[0086] The above describes the cover glass for a touch panel, the touch panel, and the method for manufacturing the cover glass for a touch panel according to this disclosure. However, this disclosure is not limited to the embodiments described above. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These also naturally fall within the technical scope of this disclosure. [Explanation of symbols]

[0087] 1 Touch panel 3. Cover glass 30 glass plates 31a Uneven surface 33 Water-repellent layer

Claims

1. A cover glass for a touch panel where pen input is performed, A glass plate having an uneven surface on the side facing the pen used for pen input, A water-repellent layer formed along the uneven surface of the glass plate, It has, The uneven surface of the glass plate is such that the contour curve is divided horizontally at regular intervals ΔX, the absolute value of the slope (angle) of the line segment connecting the start and end points of the contour curve within each section is determined, and the arithmetic mean slope angle RΔa obtained by averaging these values ​​is 5.0° or less, and the core space volume Vvc as defined in JIS B0681-3:2019 is 0.6 mL / m³. ２ ~2.6 mL / m² ２ And, The water-repellent layer is a cover glass for a touch panel, having a water contact angle (WCA) of 90° or more as defined in JIS R3257:1999.

2. The uneven surface of the glass plate has a core spatial volume Vvc and core physical volume Vmc as defined in JIS B0681-3:2019, where the sum of these volumes is 1.2 mL / m². ２ ~4.9 mL / m² ２ The cover glass for the touch panel according to claim 1.

3. The cover glass for a touch panel according to claim 1, wherein the uneven surface of the glass plate has an average length RSm of roughness curve elements defined in JIS B0601:2001 of 80 μm to 210 μm, and an arithmetic mean roughness Ra defined in JIS B0601:2001 of 0.4 μm to 2.0 μm.

4. The water-repellent layer has the chemical formula Rf ４－ｎ Six ｎ The cover glass for a touch panel according to claim 1, comprising a compound represented by (n is an integer from 1 to 3), wherein Rf has 4 or more carbon atoms and Rf comprises at least one selected from perfluoroalkyl groups, fluorine-containing ether groups, alkyl groups, and silicones, and X comprises at least one selected from halogens and hydrolyzable groups.

5. A display comprising a cover glass according to any one of claims 1 to 4, and a screen protected by the cover glass, The display is a touch panel having a touch sensor that detects the proximity of a pen to the screen of the display.

6. A method for manufacturing the cover glass of a touch panel on which pen input is performed, A process to form an uneven surface on the surface of the glass plate facing the pen used for pen input by performing blast treatment and wet etching treatment in this order, A step of forming a water-repellent layer along the uneven surface of the glass plate, It has, The uneven surface of the glass plate is such that the contour curve is divided horizontally at regular intervals ΔX, the absolute value of the slope (angle) of the line segment connecting the start and end points of the contour curve within each section is determined, and the arithmetic mean slope angle RΔa obtained by averaging these values ​​is 5.0° or less, and the core space volume Vvc as defined in JIS B0681-3:2019 is 0.6 mL / m³. ２ ~2.6 mL / m² ２ And, The water-repellent layer has a water contact angle (WCA) of 90° or more as defined in JIS R3257:1999, as a method for manufacturing a cover glass for a touch panel.

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