CN111727177B - Cover glass and embedded liquid crystal display device - Google Patents

Abstract

The invention aims to provide a protective glass and an In-cell type liquid crystal display device which can prevent white turbidity and have excellent impact resistance without increasing the thickness and the number of steps for manufacturing. The present invention relates to a protective glass, which has: a chemically strengthened glass having a first major face and a second major face; and an anti-fingerprint treatment layer provided on the first main surface, wherein the molar number of Li in all alkali metals contained in the chemically strengthened glass tensile stress layer is at most, DOL is at least 60 [ mu ] m, and the frictional charge amount on the surface of the anti-fingerprint treatment layer is at most 0kV and at least-1.5 kV.

Description

Cover glass and embedded liquid crystal display device

Technical Field

The present invention relates to a cover glass and an In-cell type liquid crystal display device.

Background

In some electronic devices such as smartphones having a liquid crystal display device, a touch function is mounted. The touch function is a function in which an operator inputs information by touching or approaching a finger to a cover glass provided on the surface of the display device.

As a structure for realizing the touch function, there is an external (out cell) type structure in which a touch panel is mounted on a liquid crystal display device.

In the case of the external type, even if one of the liquid crystal display device and the touch panel fails, the other can be used, and thus the yield is excellent, but there is a problem that the thickness and the weight are increased.

Accordingly, an in-cell (On-cell) type liquid crystal display device has appeared in which a touch panel is sandwiched between a liquid crystal element and a polarizing plate of the liquid crystal display device.

In addition, as a structure of a thinner and lighter weight than an external embedded type, an embedded type liquid crystal display device in which an element having a touch function is embedded in a liquid crystal element has been developed.

On the other hand, in-cell liquid crystal display devices (particularly IPS liquid crystal display devices) have the following problems: when the protective glass is touched with a finger, white turbidity is generated in the liquid crystal screen portion due to electrification. This is because: in the external and external embedded type, the touch panel located on the operator side of the liquid crystal element contributes to the removal of electricity, while in the embedded type liquid crystal display device, the touch panel is not disposed on the operator side of the liquid crystal element, and therefore the liquid crystal element is easily charged by static electricity. In particular, a layer for improving impact resistance and stain resistance may be formed on the surface of the protective glass, and when these layers are easily charged, white turbidity is more likely to occur.

Therefore, the following structure is proposed: in an in-cell liquid crystal display device, a conductive layer is provided on an operator side of the liquid crystal display device to discharge static electricity, thereby preventing white turbidity (patent document 1).

Prior art literature

Patent literature

Patent document 1: international publication No. 2014/069377

Disclosure of Invention

Problems to be solved by the invention

However, the structure of patent document 1 has a problem in that the thickness increases due to the provision of the conductive layer. In addition, there is a problem in that the number of steps for manufacturing the display device increases.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a cover glass and an in-cell liquid crystal display device (particularly an IPS liquid crystal display device) which can prevent white turbidity and have excellent impact resistance without increasing the thickness and the number of steps for manufacturing.

Means for solving the problems

The protective glass of the present invention is characterized by comprising: a chemically strengthened glass having a first major face and a second major face; and an anti-fingerprint treatment layer provided on the first main surface of the chemically strengthened glass, wherein the chemically strengthened glass has a maximum number of moles of Li among all alkali metals contained in the tensile stress layer, and the depth DOL of the compressive stress layer is 60 [ mu ] m or more and is formed by JIS L1094: the amount of frictional charge (frictional band) of the surface of the anti-fingerprint treatment layer, as determined by the method D described in 2014, is 0kV or less and-1.5 kV or more.

Since the frictional electrification amount of the surface of the anti-fingerprint treatment layer of the cover glass of the present invention is 0kV or less and-1.5 kV or more, even if the contact surface of a user's finger or the like is hard to be frictionally electrified, white turbidity due to static electricity can be prevented when the cover glass is assembled in a display device.

Further, since frictional electrification is suppressed by the physical properties of the protective glass, the protective glass of the present invention can prevent white turbidity without increasing the thickness and the number of steps without providing a conductive layer.

In the cover glass of the present invention, li is present in the largest molar amount of all alkali metals contained in the tensile stress layer of the chemically strengthened glass. Therefore, the compressive stress layer may contain more K, na having a larger ionic radius than Li at the time of chemical strengthening, and the surface compressive stress of the compressive stress layer is improved.

In the cover glass of the present invention, since the depth DOL of the compressive stress layer of the chemically strengthened glass is 60 μm or more, when an impact is applied from the outside, deformation due to the impact is less likely to be transmitted to the tensile stress layer, and impact resistance can be improved.

In the cover glass of the present invention, it is preferable that: li is contained in the oxide component constituting the tensile stress layer of the chemically strengthened glass ₂ O、Na ₂ O、K ₂ The total of the O concentration was A mol%, al ₂ O ₃ When the concentration of (a) is set to B mol%, a is 14.5 or more, and a×b is 120 or more.

Or preferably: in the oxide component constituting the tensile stress layer of the chemically strengthened glassLi is taken as ₂ O、Na ₂ O、K ₂ The total of the O concentrations is C mass%, al ₂ O ₃ When the concentration of (C) is set to D mass%, C is 11 or more, and C×D is 140 or more.

In this case, li is contained in an amount not contributing to the formation of a skeleton of the glass, has high mobility, and is combined with static electricity to perform charge removal ₂ O、Na ₂ O、K ₂ O, therefore, frictional electrification hardly occurs even in the contact surface of the user's finger or the like.

In this case, the material also contains a certain amount or more of Li which contributes to the formation of the skeleton ₂ O、Na ₂ O、K ₂ Al with tendency of O to approach ₂ O ₃ Thus Li ₂ O、Na ₂ O、K ₂ O enters from Al ₂ O ₃ The distance between the formed skeletons is expanded. Thus Li ₂ O、Na ₂ O、K ₂ O becomes easier to move, and frictional electrification hardly occurs even in the contact surface of the user's finger or the like.

In the cover glass of the present invention, it is preferable that: in the oxide component constituting the tensile stress layer of the chemically strengthened glass, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is 81 mol% or less.

Or preferably: in the oxide component constituting the tensile stress layer of the chemically strengthened glass, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is 82 mass% or less.

In this case, siO, which is a component contributing to the skeleton formation of glass and thus having low mobility and weak effect of removing electricity in combination with static electricity, is to be used ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The concentration of (2) is kept below a certain level, and frictional electrification is hardly generated even on the contact surface of the user's finger or the like.

The cover glass of the present invention preferably has at least one of an antiglare functional layer or an antireflection layer provided between the chemically strengthened glass and the fingerprint-resistant treatment layer.

When the cover glass of the present invention has an antiglare function layer, incident light can be scattered, and a map due to the incident light can be blurred. In the case where the cover glass of the present invention has an antireflection layer, reflection of incident light can be prevented, and mapping due to the incident light can be prevented.

The cover glass of the present invention preferably has a light shielding layer provided on the second main surface.

When the light shielding layer is provided on the second main surface, the circuit on the display device side or the illumination light of the backlight can be hidden when the protective glass is incorporated in the display device, and thus the leakage of the illumination light from the periphery of the display device can be prevented.

In the case where the protective glass of the present invention has the light shielding layer provided on the second main surface, the light shielding layer preferably has an opening, and the opening is preferably provided with an infrared transmitting layer having higher infrared transmittance than the light shielding layer.

In the case where the light shielding layer is provided with the infrared transmission layer, when the cover glass is assembled in the display device having the infrared sensor, the infrared sensor may be provided on the back side of the light shielding layer, and the infrared transmission layer may be made inconspicuous.

In the cover glass of the present invention, the chemically strengthened glass is preferably a bent glass.

In the case where the chemically strengthened glass is a bent glass, there is no concern about degradation in the accuracy of the attachment even if the object side member to which the protective glass is attached has a bent shape.

The protective glass of the present invention is preferably: an antiglare layer is provided between the first main surface and the fingerprint-preventing treatment layer, and the antiglare layer has a surface roughness expressed as Ra of 0.01 μm to 0.5 μm.

In this case, visibility can be ensured while preventing electrification.

The in-cell IPS liquid crystal display device of the present invention is characterized by having any one of the protective glasses described above.

According to the present invention, an in-cell IPS liquid crystal display device protected by a protective glass can be obtained.

Drawings

Fig. 1 is a cross-sectional view of a cover glass according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of a modified cover glass.

Fig. 3 is a cross-sectional view of a modified cover glass.

Fig. 4 (a) is a perspective view of a modified cover glass, and fig. 4 (B) is a B-B cross-sectional view of fig. 4 (a).

Fig. 5 is a cross-sectional view of a modified cover glass.

Fig. 6 is a partial cross-sectional view of a display device having a cover glass according to an embodiment of the present invention.

Detailed Description

An embodiment of the present invention will be described below with reference to the drawings.

In the present specification, when the ranges are expressed as "a to b", the ranges a to b are defined as the ranges a to b, and the ranges include the lower limit value a and the upper limit value b, respectively.

[ constitution of protective glass ]

First, the structure of the cover glass will be described.

The cover glass 1 shown in fig. 1 has a chemically strengthened glass 2 and an anti-fingerprint treatment layer 81.

The chemically strengthened glass 2 is rectangular in plan view and transmits visible light. The chemically strengthened glass 2 has a first main surface 21, a second main surface 22, and an end surface 23. A chamfer 24 is provided at the end face 23.

The chemically strengthened glass 2 has compressive stress layers 25, 32 and a tensile stress layer 27. The compressive stress layers 25 and 32 are layers in which compressive stress acts (layers in which compressive stress is 0MPa or more). The compressive stress layer 25 is provided on the surface on the first main surface 21 side, and the compressive stress layer 32 is provided on the surface on the second main surface 22 side. The compressive stress layer may be provided on the end face 23, and the description thereof is omitted here.

The tensile stress layer 27 is a layer in which tensile stress acts (a layer in which compressive stress is less than 0 MPa). The tensile stress layer 27 is disposed between the compressive stress layer 25 and the compressive stress layer 32.

The molar number of Li is the largest among all alkali metals contained in the tensile stress layer 27 of the chemically strengthened glass 2. By having a composition with the largest number of moles of Li, the compressive stress layers 25, 32 may contain more K, na having a larger ionic radius than Li during chemical strengthening. The molar number of Li is more preferably 0.5 times or more, and still more preferably 0.8 times or more, the molar number of Na.

The depth DOL (Depth of Layer) of the compressive stress layers 25, 32 of the chemically strengthened glass 2 is 60 μm or more. When the DOL is 60 μm or more, deformation due to impact is less likely to be transmitted to the tensile stress layer when impact is applied from the outside, and impact resistance of the glass surface can be improved.

The DOL is more preferably 80 μm to 250. Mu.m.

DOL theoretically refers to the depth from the surface to the position where the compressive stress is 0MPa in the plate thickness direction, and alkali ion concentration analysis (concentration analysis of ions after diffusion by chemical strengthening in this example) in the depth direction of glass can be performed by EPMA (electron probe micro analyzer ), and the ion diffusion depth obtained by measurement is regarded as DOL. DOL may also be measured using a surface stress meter (e.g., FSM-6000 manufactured by the manufacturing of folding elements).

Li is added to the oxide component constituting the tensile stress layer of the chemically strengthened glass 2 ₂ O、Na ₂ O、K ₂ The total of the O concentration was A mol%, al ₂ O ₃ When the concentration of (a) is set to B mol%, a is preferably 14.5 or more and a×b is preferably 120 or more. More preferably, A is 15 to 20 and A.times.B is 170 to 300.

In the case where a is represented by mass (Li is contained in the oxide component constituting the tensile stress layer ₂ O、Na ₂ O、K ₂ When the total of the O concentration is C mass%, the total content depends on the content of each component with respect to Li ₂ O、Na ₂ O、K ₂ The total molar ratio of O is preferably 11 or more, more preferably 12 to 20.

In the case of A.times.B by mass (Li in the oxide component constituting the tensile stress layer ₂ O、Na ₂ O、K ₂ The total of the O concentrations is C mass%, al ₂ O ₃ The concentration of (C) is represented by C X D, although it depends on the relative Li of each component ₂ O、Na ₂ O、K ₂ The total molar ratio of O is preferably 140 or more, more preferably 150 to 400.

The reason is as follows.

The components constituting the glass are basically classified into components contributing to the formation of the skeleton of the glass (also referred to as network formers) and components not contributing to the formation of the skeleton.

Among them, from the viewpoint of preventing electrification, a component which does not contribute to the formation of a skeleton is preferably more. This is thought to be because: the mobility of the component that does not contribute to the formation of the skeleton is high as compared with the component that contributes to the formation of the skeleton, and thus the neutralization is performed in combination with static electricity. Li (Li) ₂ O、Na ₂ O、K ₂ O is a component that does not contribute to the formation of the skeleton in the glass, and therefore the content of these components is preferably larger, that is, it is preferable that A and C described above are larger. This is the basis for the provision of a.

In addition, al ₂ O ₃ As both components contributing to the formation of the skeleton and as components not contributing to the formation of the skeleton. At Al ₂ O ₃ Contributing to the formation of the skeleton, has a structure similar to Li ₂ O、Na ₂ O、K ₂ O tends to approach. Al (Al) ₂ O ₃ With Li ₂ O、Na ₂ O、K ₂ When O approaches, li ₂ O、Na ₂ O、K ₂ O enters between components forming the framework, so that the distance between the frameworks is expanded. When the distance between the frames is expanded, components which do not contribute to the formation of the frames are easily moved between the frames, and mobility is increased, so that it is preferable. This is why a×b is defined.

The triboelectric charging is a phenomenon that occurs on the surface of the compressive stress layer 25, and the reason why the preferable composition of the tensile stress layer 27 is defined is as follows.

Since it is the skeleton of glass that affects the triboelectric charging, it is originally desired to define the structure of the glass. However, since glass is amorphous and it is sometimes difficult to specify a (specific) structure, it is preferable to specify the composition. On the other hand, the compressive stress layer 25 is ion-exchanged by chemical strengthening, and therefore has a composition different from that of the tensile stress layer 27, but the network structure of the glass is the same. If glass having the same composition as that of the compressive stress layer 25 is manufactured without chemical strengthening, the network structure is different, and therefore it is difficult to specify (specifically prescribe) the structure of the compressive stress layer 25 by using the composition of the compressive stress layer 25. Therefore, the structure of the (specific) tensile stress layer 27 is specified by specifying the composition of the (specific) tensile stress layer 27, and even if chemical strengthening is performed, the structures of the tensile stress layer 27 and the compressive stress layer 25 are not changed, and the structure of the (specific) compressive stress layer 25 is specified by using this point in accordance with the composition of the tensile stress layer 27.

Of the oxide components constituting the tensile stress layer 27 of the chemically strengthened glass 2, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is preferably 81 mol% or less. This is because these elements are components contributing to the formation of the skeleton of the glass, and therefore, the smaller the content is, the more components contributing to the removal of electricity are. In addition, because the smaller the content of these components is, the wider the distance between the components forming the skeleton is, and the higher the mobility of the components not contributing to the skeleton formation is.

The triboelectric charging is a phenomenon occurring on the surface of the compressive stress layer 25, and the reason for defining the preferable composition of the tensile stress layer is the same as the reason for defining A, A ×b.

SiO is expressed as mass percent ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ In the case of the total concentration of (2), the total content of the components is preferably 82 mass% or less, more preferably 70 to 81 mass%, although the molar ratio of the components to the total is also determined.

More specifically, the composition of the tensile stress layer 27 is preferably the following glass composition: based on the mass percent of the oxideThe rate represents that the SiO content is 55 to 68 percent ₂ 10 to 25 percent of Al ₂ O ₃ 0 to 5 percent of B ₂ O ₃ 0 to 15 percent of P ₂ O ₅ 0 to 8 percent of Li ₂ O, 1-20% Na ₂ O, 0.1-10% K ₂ O, mgO 0-10%, caO 0-5%, srO 0-5%, baO 0-5%, znO 0-5% and TiO 0-1% ₂ ZrO 0-5% ₂ And 0.005% -0.1% Fe ₂ O ₃ 。

The composition of the tensile stress layer 27 can be quantified by a known composition analysis method such as chemical analysis, absorbance analysis, atomic absorbance analysis, and fluorescent X-ray analysis. The measurement position may be any position of the tensile stress layer 27, and is preferably a center position in the thickness direction of the glass substrate and a center position on a plane.

The following describes each component in the preferred glass composition of the tensile stress layer 27. In the following description of the glass composition, unless otherwise specified, the content expressed in% means the content expressed in mass percent based on the oxide.

SiO ₂ Is a component constituting the skeleton of glass. In addition, siO ₂ Is a component for improving chemical durability, and is a component for reducing occurrence of cracks when flaws (indentations) are formed on the surface of glass. To suppress the generation of cracks, siO ₂ The content is preferably 55% or more, more preferably 56% or more, further preferably 56.5% or more, particularly preferably 58% or more. On the other hand, in order to improve the mobility of an element contributing to the removal of electricity in glass and to improve the meltability in the glass manufacturing process, siO ₂ The content is preferably 68% or less, more preferably 65% or less, further preferably 63% or less, particularly preferably 61% or less.

Al ₂ O ₃ Is effective for improving ion exchange performance in chemical strengthening treatment and increasing surface compressive stress CS after chemical strengthening. In addition, al ₂ O ₃ Has the effect of improving the fracture toughness value of the glass. In addition, al ₂ O ₃ Is a component that increases Tg of glass, and also a component that increases Young's modulus. In addition, al ₂ O ₃ Also has the effect of improving the mobility of the element contributing to the charge removal in the glass. To improve these characteristics, al ₂ O ₃ The content is preferably 10% or more, more preferably 12% or more. In addition, to increase the fracture toughness value, al ₂ O ₃ The content is more preferably 14% or more. On the other hand, from the viewpoint of increasing the content of an element contributing to removal of electricity in the glass, and from the viewpoint of maintaining the acid resistance of the glass and reducing the devitrification temperature, al ₂ O ₃ The content of (2) is preferably 25% or less, more preferably 23% or less.

In addition, al ₂ O ₃ Is a constituent of lithium aluminosilicate crystals. To suppress crystal precipitation during bending, al ₂ O ₃ The content of (2) is preferably 22% or less, more preferably 20% or less, and still more preferably 19% or less.

B ₂ O ₃ Is a component for improving the meltability of glass. In addition, B ₂ O ₃ Is also a component for improving chipping resistance of glass. B (B) ₂ O ₃ Not essential components, but in the presence of B ₂ O ₃ In order to improve the meltability, the content thereof is preferably 0.1% or more, more preferably 0.5% or more, and still more preferably 1% or more. On the other hand, from the viewpoint of improving the mobility of the element contributing to the charge removal in the glass and the viewpoint of preventing the generation of striae at the time of melting, B ₂ O ₃ The content of (2) is preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, and particularly preferably 2.5% or less.

P ₂ O ₅ Is a component for improving ion exchange performance and chipping resistance during chemical strengthening treatment. P (P) ₂ O ₅ Not essential components, but in the presence of P ₂ O ₅ In the case of (2), the content is preferably 0.1% or more, more preferably 1% or more, and even more preferably 2% or more. On the other hand, P for securing acid resistance and preventing electrification ₂ O ₅ The content of (2) is preferably 15% or less, more preferably 10% or lessFurther, the content is preferably 8% or less, more preferably 6% or less, and particularly preferably 4% or less.

Li ₂ O is a component for forming a surface compressive stress layer by chemical strengthening treatment with sodium salts such as sodium nitrate. In addition, li ₂ O is a substance in the glass that contributes to the removal of electricity.

To obtain Li-containing ₂ Effect of O, li ₂ The content of O is preferably 0.1% or more, more preferably 1% or more, and still more preferably 2% or more. On the other hand, from the viewpoint of ensuring weather resistance, li ₂ The content of O is preferably 8% or less. In addition, in order to suppress crystal precipitation during bending, li ₂ The content of O is preferably 7% or less, more preferably 6% or less.

Na ₂ O is a component that forms a surface compressive stress layer in a chemical strengthening treatment using a potassium salt, and is a component that can improve the meltability of glass. In addition, na ₂ O is a substance in the glass that contributes to the removal of electricity.

To obtain this effect, na ₂ The content of O is preferably 1% or more, more preferably 1.5% or more, and still more preferably 2% or more. On the other hand, in order to increase the surface compressive stress CS, na ₂ The content of O is preferably 20% or less, more preferably 16% or less, further preferably 14% or less, particularly preferably 8% or less.

K ₂ O is a substance that improves the meltability of the glass. In addition, K ₂ O is a substance in the glass that contributes to the removal of electricity. In the presence of K ₂ In the case of O, the content is preferably 0.1% or more, more preferably 0.5% or more. On the other hand, from the viewpoint of securing the breakage of the chemically strengthened glass, K ₂ The content of O is preferably 8% or less, more preferably 5% or less, and still more preferably 3% or less.

MgO is not an essential component, but is preferably contained in order to increase the surface compressive stress CS of the chemically strengthened glass. In addition, mgO has an effect of improving fracture toughness value. Therefore, the content of MgO is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 2% or more. On the other hand, in order to suppress devitrification in glass melting, the MgO content is preferably 10% or less, more preferably 8% or less, and still more preferably 6% or less.

CaO is not an essential component, but may be a component for improving the meltability of the glass. When CaO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more, and still more preferably 0.15% or more. On the other hand, from the viewpoint of securing ion exchange performance at the time of the chemical strengthening treatment, the content of CaO is preferably 3.5% or less, more preferably 2.0% or less, and still more preferably 1.5% or less.

SrO is not an essential component, but SrO is a component for improving the meltability of glass and may be contained. When SrO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more, and still more preferably 0.5% or more. On the other hand, in order to improve the ion exchange performance in the chemical strengthening treatment, the content of SrO is preferably 5% or less, more preferably 3.5% or less, further preferably 2% or less, and particularly preferably substantially no SrO is contained.

BaO is not an essential component, but BaO is a component for improving the meltability of glass and may be contained. When BaO is contained, the content is preferably 0.1% or more, more preferably 0.5% or more, and still more preferably 1% or more. On the other hand, in order to improve the ion exchange performance in the chemical strengthening treatment, the content of BaO is preferably 5% or less, more preferably 3% or less, further preferably 2% or less, and further preferably substantially no BaO.

ZnO is a component for improving the meltability of glass, and may be contained. When ZnO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more. On the other hand, when the ZnO content is 5% or less, the weather resistance of the glass can be improved, and thus it is preferable. The ZnO content is more preferably 3% or less, still more preferably 1% or less, and particularly preferably substantially no ZnO.

TiO ₂ Is a component for inhibiting change in glass color due to sun exposure, and may contain TiO ₂ . Containing TiO ₂ In the case of (C), the content thereof is preferably 0.01% or more, more preferablyMore preferably 0.03% or more, still more preferably 0.05% or more, and particularly preferably 0.1% or more. On the other hand, in order to suppress devitrification at the time of melting, tiO ₂ The content of (2) is preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.2% or less.

ZrO ₂ Is a component for increasing the surface compressive stress CS formed by ion exchange during the chemical strengthening treatment, and may contain ZrO ₂ . Containing ZrO ₂ In the case of (2), the content is preferably 0.1% or more, more preferably 0.5% or more, and still more preferably 1% or more. On the other hand, zrO may be used to improve the quality of chemically strengthened glass by suppressing devitrification during melting ₂ The content of (2) is preferably 5% or less, more preferably 3% or less, and particularly preferably 2.5% or less.

Fe ₂ O ₃ Absorbing heat rays, thereby having an effect of improving the meltability of glass, and preferably containing Fe in the case of mass-producing glass using a large-scale melting furnace ₂ O ₃ . In this case Fe ₂ O ₃ The content of (2) is preferably 0.005% or more, more preferably 0.006% or more, and even more preferably 0.007% or more. On the other hand, the Fe is contained in excess ₂ O ₃ In this case, coloring occurs, so that Fe is added to improve transparency of the glass ₂ O ₃ The content of (2) is preferably 0.1% or less, more preferably 0.05% or less, still more preferably 0.02% or less, particularly preferably 0.015% or less.

In this case, all of the iron oxide in the glass is represented by Fe ₂ O ₃ Although the form of (c) is illustrated, in practice, fe (III) in the oxidized state and Fe (II) in the reduced state are usually mixed. Wherein Fe (III) produces a yellow coloration, fe (II) produces a blue coloration, and in the balance of both, the glass produces a green coloration.

The chemically strengthened glass 2 may contain Y ₂ O ₃ 、La ₂ O ₃ 、Nb ₂ O ₅ . When these components are contained, the total content thereof is preferably 0.01% or more, more preferably 0.05% or more, still more preferably 0.1% or more, particularly preferably 0.15% or more, and most preferablyMore than 1 percent. On the other hand, Y ₂ O ₃ 、La ₂ O ₃ 、Nb ₂ O ₅ If the content of (b) is too large, devitrification of the glass tends to occur during melting, and the quality of the chemically strengthened glass may be lowered, so that the total content of these is preferably set to 7% or less. Y is Y ₂ O ₃ 、La ₂ O ₃ 、Nb ₂ O ₅ The total content of (2) is more preferably 6% or less, still more preferably 5% or less, particularly preferably 4% or less, and most preferably 3.5% or less.

In order to improve the crushability of the chemically strengthened glass, a small amount of Ta may be contained ₂ O ₅ 、Gd ₂ O ₃ However, since the refractive index and the reflectance are improved, the total content thereof is preferably 5% or less, more preferably 2% or less, and even more preferably not containing Ta ₂ O ₅ 、Gd ₂ O ₃ 。

In addition, in the case where the glass is colored, a coloring component may be added in a range that does not inhibit the achievement of desired chemical strengthening characteristics. Examples of the coloring component include: co (Co) ₃ O ₄ 、MnO ₂ 、NiO、CuO、Cr ₂ O ₃ 、V ₂ O ₅ 、Bi ₂ O ₃ 、SeO ₂ 、CeO ₂ 、Er ₂ O ₃ 、Nd ₃ O ₃ And the like as suitable coloring components.

When the total content of the coloring components is 7% or less, problems such as devitrification are less likely to occur, and thus it is preferable. The content is preferably 5% or less, more preferably 3% or less, and even more preferably 2% or less. In the case where the visible light transmittance of the glass is prioritized, these components are preferably substantially not contained.

Can properly contain SO ₃ Chlorides, fluorides, etc. act as fining agents when the glass is melted. As As ₂ O ₃ It is preferable that the composition is not contained because it is heavy in environmental load. In the presence of Sb ₂ O ₃ In the case of (2), it is preferably 1% or less, more preferably 0.5% or less, and most preferably no Sb is contained ₂ O ₃ 。

The surface compressive stress CS of the chemically strengthened glass 2 is preferably 300MPa to 1500MPa.

By setting CS to 300MPa or more, bending strength required for the protective glass can be maintained. When CS is 1500MPa or less, scattering of fragments at the time of fracture can be prevented. CS is more preferably 800MPa to 1200MPa.

The surface compressive stress CS herein refers to the compressive stress of the outermost surface of the glass. The surface compressive stress CS may be measured using a surface stress meter (e.g., FSM-6000 manufactured by the manufacturing of folding elements) or the like.

The internal tensile stress CT of the chemically strengthened glass 2 is preferably 20MPa to 100MPa.

By setting CT to 20MPa or more, a state in which the compressive stress existing as a reaction is an appropriate stress value and depth can be achieved. By setting CT to 100MPa or less, scattering of fragments at the time of fracture can be prevented. CT is more preferably 40MPa to 85MPa.

The internal tensile stress CT is approximately obtained by the relation ct= (cs×dol)/(t-2×dol) assuming that the thickness of the cover glass 1 is t.

The anti-fingerprint treatment layer 81 is a layer that reduces the adhesion of stains caused by fingerprints, sebum, sweat, etc. when a human finger touches the first main surface 21.

The constituent material of the fingerprint-preventing layer 81 may be appropriately selected from fluorine-containing organic compounds and the like capable of imparting antifouling property, water repellency, and oil repellency. Specifically, a fluorine-containing organosilicon compound and a fluorine-containing hydrolyzable silicon compound are exemplified. The fluorine-containing organic compound may be used without particular limitation as long as it imparts antifouling property, water repellency and oil repellency.

In the present embodiment, the fluorine-containing organic compound originally has a characteristic of being easily charged when it is formed on chemically strengthened glass by finger touch, and the frictional charge amount of the surface of the anti-fingerprint treatment layer 81 is 0kV or less and-1.5 kV or more, so that charging can be suppressed.

A fluorine-containing organosilicon compound coating film forming the anti-fingerprint treatment layer 81 is formed on the first main surface 21 of the chemically strengthened glass 2. Or in the case where an antiglare layer is formed on the first main surface 21 and an antireflection layer is formed on the surface thereof, it is preferable to form the fingerprint-preventing treatment layer 81 on the surface of the antireflection layer. In the case of using a glass substrate in which the first main surface 21 of the chemically strengthened glass 2 is subjected to a surface treatment such as antiglare treatment without forming an antireflection layer, the fluorine-containing organosilicon compound coating is preferably directly formed on the surface subjected to the surface treatment.

The fluorine-containing hydrolyzable silicon compound used for forming the fluorine-containing organosilicon compound coating film is not particularly limited as long as the resulting fluorine-containing organosilicon compound coating film has antifouling properties such as water repellency and oil repellency. Specifically, fluorine-containing hydrolyzable silicon compounds having one or more groups selected from the group consisting of perfluoropolyether groups, perfluoroalkylene groups and perfluoroalkyl groups are exemplified.

As a material for forming the fingerprint-preventing layer 81, for example, commercially available "KP-801" (trade name, manufactured by Xinshi chemical Co., ltd.), "X-71" (trade name, manufactured by Xinshi chemical Co., ltd.), "KY-130" (trade name, manufactured by Xinshi chemical Co., ltd.), "KY-178" (trade name, manufactured by Xinshi chemical Co., ltd.), "KY-185" (trade name, manufactured by Xinshi chemical Co., ltd.), "KY-195" (trade name, manufactured by Xinshi chemical Co., ltd.), "OPTOOL" (registered trade name), DSX (trade name, manufactured by Dain chemical Co., ltd.) and the like can be used. In addition, oil and antistatic agents may be added to these commercial products for use.

The thickness of the anti-fingerprint treatment layer 81 is not particularly limited, but is preferably 2nm to 20nm, more preferably 2nm to 15nm, and still more preferably 3nm to 10nm. If the layer thickness is 2nm or more, the surface of the antireflection layer is uniformly covered with the anti-fingerprint treatment layer 81, and the anti-fingerprint property and scratch resistance can be subjected to practical use. If the layer thickness is 20nm or less, the optical properties such as visual reflectance (viewing reflectance) and haze value in the state of the laminated anti-fingerprint treatment layer 81 are good.

The frictional charge amount at the surface of the fingerprint-preventing treated layer 81 of the cover glass 1 is 0kV or less and-1.5 kV or more. The frictional charge amount referred to herein means a charge amount obtained by JIS L1094:2014 (triboelectric damping method). The fluorine-based fingerprint-preventing layer is negatively charged in the above-described evaluation method, and by setting it to-1.5 kV or more, electrification can be prevented.

The frictional electrification amount is more preferably 0kV to-1 kV.

The above is a description of the structure of the cover glass 1.

[ method for producing protective glass 1 ]

Next, an example of a method for producing the cover glass 1 will be described.

First, chemically strengthened glass 2 is produced.

The chemically strengthened glass 2 is produced by subjecting a glass for chemical strengthening produced by a usual glass production method to a chemical strengthening treatment.

The chemical strengthening treatment is a treatment of forming a surface layer having compressive stress by subjecting the surface of glass to ion exchange treatment. Specifically, ion exchange treatment is performed at a temperature equal to or lower than the glass transition temperature of the glass for chemical strengthening, and metal ions (typically Li ions or Na ions) having a small ion radius, which are present near the surface of the glass sheet, are replaced with ions having a large ion radius (typically Na ions or K ions for Li ions and K ions for Na ions).

The chemically strengthened glass 2 can be produced by, for example, subjecting a chemically strengthened glass having the composition of the tensile stress layer 27 to a chemical strengthening treatment.

The following manufacturing method is an example in the case of manufacturing a plate-shaped chemically strengthened glass.

First, glass raw materials are prepared, and heated and melted in a glass melting furnace. Then, the glass is homogenized by bubbling, stirring, adding a fining agent, etc., and a glass plate having a predetermined thickness is formed by a conventionally known forming method, and is gradually cooled. Alternatively, the sheet may be formed into a sheet by a method of forming the sheet into a block, gradually cooling the block, and then cutting the block.

Examples of the method for forming the sheet-like material include: float, press, fusion and downdraw processes. Particularly in the case of manufacturing a large glass sheet, a float method is preferable. In addition, continuous forming methods other than the float method, such as a fusion method and a downdraw method, are also preferable.

Then, the formed glass is cut into a predetermined size and chamfered. The chamfering is preferably performed so that the dimension of the chamfering portion 24 in a plan view is 0.05mm or more and 0.5mm or less.

Next, the glass sheet is subjected to about one or about two (about one stage or about two stages) ion exchange treatments, thereby performing chemical strengthening, forming the compressive stress layers 25, 32 and the tensile stress layer 27.

In the chemical strengthening step, the glass to be treated is brought into contact with a molten salt (e.g., potassium salt or sodium salt) containing an alkali metal ion having an ion radius larger than that of the alkali metal ion (e.g., sodium ion or lithium ion) contained in the glass in a temperature range not exceeding the glass transition temperature.

The alkali metal ions in the glass are ion-exchanged with alkali metal ions having a large ionic radius of the alkali metal salt, and compressive stress is generated on the surface of the glass by the difference in the occupied volume of the alkali metal ions, thereby forming a compressive stress layer. The temperature range in which the glass is brought into contact with the molten salt may be a temperature range not exceeding the glass transition temperature, and is preferably 50 ℃ or lower than the glass transition temperature. Thereby preventing stress relaxation of the glass.

In the chemical strengthening treatment, the treatment temperature and treatment time at which the glass is brought into contact with the molten salt containing alkali metal ions may be appropriately adjusted depending on the compositions of the glass and the molten salt. The temperature of the molten salt is usually preferably 350 ℃ or higher, more preferably 370 ℃ or higher, and further usually 500 ℃ or lower, more preferably 450 ℃ or lower.

By setting the temperature of the molten salt to 350 ℃ or higher, chemical strengthening is prevented from being difficult to be performed due to a decrease in the ion exchange rate. In addition, by setting the temperature of the molten salt to 500 ℃ or lower, decomposition and degradation of the molten salt can be suppressed.

In order to impart sufficient compressive stress, the time for bringing the glass into contact with the molten salt is usually preferably 10 minutes or more, more preferably 15 minutes or more each time. In addition, in the case of long-time ion exchange, since the productivity is lowered and the compressive stress value is lowered by relaxation, the time for bringing the glass into contact with the molten salt is usually 20 hours or less, preferably 16 hours or less at a time.

The number of times of chemical strengthening is exemplified as one time or two times, but the number of times is not particularly limited as long as the physical properties (DOL, CS, CT) of the target compressive stress layer and tensile stress layer can be obtained. The reinforcement may be performed three or more times. In addition, a heat treatment step may be performed between the two strengthening steps. In the following description, the case of performing chemical strengthening three times and the case of performing a heat treatment process between the two strengthening are referred to as three-stage strengthening.

The three-stage strengthening may be performed by, for example, strengthening treatment method 1 or strengthening treatment method 2 described below.

(strengthening treatment method 1)

In the strengthening treatment method 1, first, li is contained ₂ The glass for chemical strengthening of O is contacted with a metal salt (first metal salt) containing sodium (Na) ions, so that the Na ions in the metal salt are ion-exchanged with Li ions in the glass. Hereinafter, this ion exchange treatment may be referred to as "first-stage treatment".

In the first treatment, for example, the chemically strengthened glass is immersed in a metal salt containing Na ions (e.g., sodium nitrate) at a temperature of about 350 ℃ to about 500 ℃ for about 0.1 hour to about 24 hours. In order to improve productivity, the treatment time in the first step is preferably 12 hours or less, more preferably 6 hours or less.

By the first step treatment, a deep compressive stress layer is formed on the surface of the glass, and a stress distribution in which CS is 200MPa or more and a compressive stress depth DOL is 1/8 or more of the plate thickness can be formed. In addition, the glass subjected to the first step has a large internal tensile stress CT and thus has a large breakage. However, since the crushability can be improved by the subsequent treatment, it is preferable that the CT at this stage is large. The internal tensile stress CT of the glass subjected to the first treatment is preferably 90MPa or more, more preferably 100MPa or more, and still more preferably 110MPa or more. This is because the surface compressive stress CS of the compressive stress layer 25 increases.

The first metal salt is an alkali metal salt, and as an alkali metal ion, na ion is contained in the largest amount. The first metal salt may contain Li ions, but the Li ions are preferably 2% or less, more preferably 1% or less, and still more preferably 0.2% or less, based on 100% by mol of the alkali ions. In addition, the first metal salt may contain K ions. The K ion is preferably 20% or less, more preferably 5% or less, based on 100% by mole of the alkali ion contained in the first metal salt.

Next, the glass after the first treatment is brought into contact with a metal salt (second metal salt) containing lithium (Li) ions, and the value of compressive stress in the vicinity of the surface layer is reduced by ion exchange between Li ions in the metal salt and Na ions in the glass. This process is sometimes referred to as a "second-step process".

Specifically, for example, the glass having undergone the first-step treatment is immersed in a metal salt containing Na and Li (for example, a mixed salt of sodium nitrate and lithium nitrate) at a temperature of about 350 to about 500 ℃ for about 0.1 to about 24 hours. In order to improve productivity, the second-step treatment time is preferably 12 hours or less, more preferably 6 hours or less.

The glass treated in the second step can reduce the internal tensile stress, and can not be broken severely during the breaking process.

The second metal salt is an alkali metal salt, and preferably contains Na ion and Li ion as alkali metal ions. In addition, the second metal salt is preferably a nitrate. The total mole number of Na ions and Li ions is preferably 50% or more, more preferably 70% or more, and still more preferably 80% or more, based on 100% by mole number of alkali metal ions contained in the second metal salt. By adjusting the Na/Li molar ratio, the stress distribution in DOL/4 to DOL/2 can be controlled.

The optimum value of the Na/Li molar ratio of the second metal salt varies depending on the glass composition, and is preferably 0.3 or more, more preferably 0.5 or more, and still more preferably 1 or more. In order to increase the compressive stress value of the compressive stress layer while reducing CT, it is preferably 100 or less, more preferably 60 or less, and further preferably 40 or less.

In the case where the second metal salt is a sodium nitrate-lithium nitrate mixed salt, the mass ratio of sodium nitrate to lithium nitrate is, for example, preferably 25: 75-99: 1, more preferably 50: 50-98: 2, more preferably 70: 30-97: 3.

next, the glass after the second treatment is brought into contact with a metal salt (third metal salt) containing potassium (K) ions, and a large compressive stress is generated on the surface of the glass by ion exchange between K ions in the metal salt and Na ions in the glass. This ion exchange treatment is sometimes referred to as "third step treatment".

Specifically, for example, the glass after the second treatment is immersed in a metal salt containing K ions (for example, potassium nitrate) at a temperature of about 350 to about 500℃for about 0.1 to about 10 hours. By this process, a large compressive stress can be formed in the region of about 0 μm to about 10 μm of the glass surface layer.

The third step of treatment increases only the compressive stress at a shallow portion of the glass surface and has little effect on the inside, so that a large compressive stress can be formed in the surface layer while suppressing the tensile stress in the inside.

The third metal salt is an alkali metal salt, and may contain Li ions as alkali metal ions, but the Li ions are preferably 2% or less, more preferably 1% or less, and still more preferably 0.2% or less based on 100% by mole of the alkali metal ions contained in the third metal salt. The Na ion content is preferably 2% or less, more preferably 1% or less, and even more preferably 0.2% or less.

In the strengthening treatment method 1, the total of the treatment time of the first to third steps can be 24 hours or less, and therefore, the productivity is preferably high. The total treatment time is more preferably 15 hours or less, and still more preferably 10 hours or less.

(strengthening treatment method 2)

In the strengthening treatment method 2, first, li is contained ₂ The glass for chemical strengthening of O is contacted with a first metal salt containing sodium (Na) ions, and the Na ions in the metal salt are ion-exchanged with Li ions in the glass, and the first treatment is performed.

The first step is the same as in the case of the reinforcement processing method 1, and therefore, the description thereof is omitted.

Next, the heat treatment is performed without contacting the glass, which has been subjected to the first step treatment, with a metal salt. This is referred to as the second step process.

For example, the glass after the first treatment is kept in the atmosphere at a temperature of 350 ℃ or higher for a certain period of time, and then subjected to the second treatment. The holding temperature is a temperature equal to or lower than the strain point of the glass for chemical strengthening, preferably equal to or lower than a temperature 10 ℃ higher than the first-stage treatment temperature, and more preferably equal to the first-stage treatment temperature.

Consider that: according to this treatment, thermal diffusion of alkali ions introduced into the glass surface by the first-step treatment occurs, whereby CT is reduced.

Then, the glass after the second treatment is brought into contact with a third metal salt containing potassium (K) ions, and a large compressive stress is generated on the surface of the glass by ion exchange between K ions in the metal salt and Na ions in the glass. This ion exchange treatment is sometimes referred to as "third step treatment".

The third step is the same as in the case of the reinforcement processing method 1, and therefore, the explanation thereof is omitted.

In the strengthening treatment method 2, the total of the treatment time of the first to third steps may be 24 hours or less, and therefore, it is preferable that the productivity is high. The total treatment time is more preferably 15 hours or less, and still more preferably 10 hours or less.

According to the strengthening treatment method 1, the stress distribution can be precisely controlled by adjusting the composition of the second metal salt used in the second treatment and the treatment temperature.

According to the strengthening treatment method 2, chemically strengthened glass excellent in characteristics can be obtained at low cost by relatively simple treatment.

The treatment conditions of the chemical strengthening treatment may be appropriately selected in consideration of the characteristics and composition of the glass, the type of molten salt, and the like, and the time, temperature, and the like.

The chemically strengthened glass 2 is produced by the above steps.

Next, an anti-fingerprint treatment layer 81 is formed on the first main surface 21 of the chemically strengthened glass 2.

As a method for forming the fingerprint-preventing layer 81, the following method can be used: a vacuum vapor deposition method (dry method) in which a fluorine-containing organic compound or the like is evaporated in a vacuum tank and then adhered to the surface of the antireflection layer; and a method (wet method) in which an organic compound containing fluorine or the like is dissolved in an organic solvent so as to be adjusted to a predetermined concentration and applied to the surface of the antireflection layer.

The dry method may be appropriately selected from an ion beam assisted vapor deposition method, an ion plate method, a sputtering method, a plasma CVD method, and the like, and the wet method may be appropriately selected from a spin coating method, a dip coating method, a casting method, a slit coating method, a spray coating method, and the like. Either a dry method or a wet method may be used.

Examples of the method for forming the fluorine-containing organosilicon compound coating film include coating a film having a perfluoroalkyl group by spin coating, dip coating, casting, slit coating, spraying, or the like; a method of heat-treating a composition of a fluoroalkyl group-containing silane coupling agent such as a fluoroalkyl group containing a perfluoro (polyoxyalkylene) chain, or a vacuum vapor deposition method of vapor-depositing a fluorine-containing organosilicon compound and then heat-treating the same. The concentration of the solution in the case of applying by the spray method is preferably 0.15 mass% or less, and more preferably 0.1 mass% or less.

The formation of the fluorine-containing organosilicon compound coating is preferably carried out using a coating-forming composition containing a fluorine-containing hydrolyzable silicon compound.

The above description is about an example of the method for producing the cover glass 1.

[ effect of protective glass 1 ]

Since the frictional electrification amount of the surface of the anti-fingerprint treatment layer 81 of the cover glass 1 is 0kV or less and-1.5 kV or more, even if the contact surface of a user's finger or the like is hard to be frictionally electrified, white turbidity due to static electricity can be prevented when the cover glass is assembled in a display device.

Since frictional electrification is suppressed by the physical properties of the chemically strengthened glass 2, the cover glass 1 can prevent white turbidity without providing a conductive layer and without increasing the thickness and the number of steps.

The depth DOL of the compressive stress layers 25, 32 of the chemically strengthened glass 2 of the protective glass 1 is 60 μm or more. Therefore, when an impact is applied from the outside, deformation due to the impact is less likely to be transmitted to the tensile stress layer, and the impact resistance of the glass surface can be improved.

Among the oxide components constituting the tensile stress layer of the cover glass 1, li, which does not contribute to the formation of the skeleton of the glass, has high mobility, and is combined with static electricity to perform charge removal ₂ O、Na ₂ O、K ₂ The total of the O concentrations was A mol%, and Al was used ₂ O ₃ When the concentration of (a) is set to B mol%, a is preferably 14.5 or more and a×b is preferably 120 or more. Or Li is added to the oxide component constituting the tensile stress layer ₂ O、Na ₂ O、K ₂ The total of the O concentrations was C mass%, and Al was used as the catalyst ₂ O ₃ When the concentration of (C) is D mass%, C is preferably 11 or more and c×d is preferably 140 or more.

In such a case, li is contained in an amount not contributing to the formation of a skeleton of the glass, has high mobility, and is combined with static electricity to perform charge removal ₂ O、Na ₂ O、K ₂ O, it is therefore more difficult to triboelectrically charge even the contact surface of the user's finger or the like.

In addition, since it also contains a certain amount or more of a compound which contributes to the formation of a skeleton and is bonded with Li ₂ O、Na ₂ O、K ₂ Al close to O ₂ O ₃ Thus Li ₂ O、Na ₂ O、K ₂ O enters between networks to expand the distance. Thus Li ₂ O、Na ₂ O、K ₂ O becomes easier to move and even the contact surface of the user's finger or the like becomes more difficult to triboelectrically charge.

Among oxide components constituting the tensile stress layer of the chemically strengthened glass 2, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ When the total concentration of (a) is 81 mol% or less (or 82 mass%) of SiO, which is a component contributing to the formation of a skeleton of glass, having high mobility and having a weak effect of removing electricity by electrostatic bonding ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ Is inhibited to a concentration ofAnd not more than a certain level, it is more difficult to triboelectrically charge even the contact surface of the user's finger or the like.

Modification example

The present invention is not limited to the above embodiments, and various modifications, design changes, and the like can be made without departing from the spirit of the present invention. The specific steps, structures, and the like in the practice of the present invention may be other structures, and the like, as long as the objects of the present invention can be achieved.

The chemically strengthened glass 2 may be a plate having not only a flat surface but also a plate having at least a curved surface or a concave portion. For example, as shown in fig. 2, the chemically strengthened glass 2 may be a bent glass. By using the bent glass, there is no fear of degradation in the accuracy of mounting even if the object side member to which the cover glass 1 is mounted has a bent shape.

The thickness of the chemically strengthened glass 2 is preferably 0.5mm or more. The glass having a thickness of 0.5mm or more has the advantage of providing a protective glass 1 having both high strength and good texture. The thickness is more preferably 0.7mm or more. In the case of using the composition for a vehicle-mounted display device, it is preferably 1.1mm or more in order to secure the impact resistance against the head impact test. From the viewpoint of weight reduction and ensuring transmittance, it is preferably 5mm or less, more preferably 3mm or less.

The planar shape of the chemically strengthened glass 2 is not particularly limited. The areas of the first main surface 21 and the second main surface 22 are also not particularly limited, and are, for example, about 5000mm ² About 50000mm ² 。

As shown in fig. 3, at least one of an antiglare layer subjected to an antiglare treatment (AG treatment) or an antireflection layer subjected to an antireflection treatment (AR treatment) may be provided as the functional layer 3 on at least one of the first main surface 21 and the second main surface 22 of the chemically strengthened glass 2.

In the case where the antiglare layer or the antireflection layer is provided on the first main surface 21, an antiglare function layer or an antireflection layer is provided between the chemically strengthened glass 2 and the fingerprint-treating layer 81.

By providing the antiglare layer as the functional layer 3, light incident from the first main surface 21 side can be scattered, and the mapping by the incident light can be blurred.

As a method for imparting antiglare properties, a method of forming a concave-convex shape on the first main surface 21 of the chemically strengthened glass 2 is exemplified. The antiglare layer may be provided after the chemical strengthening or the chemical strengthening treatment may be performed after the antiglare layer is provided.

As a method for forming the concave-convex shape, a known method can be applied. A method of forming an etched layer by subjecting the first main surface 21 of the chemically strengthened glass 2 to chemical or physical surface treatment to form a desired roughness of the surface, or a method of adhering a coating layer such as an antiglare film, may be used.

When the antiglare layer is an etching layer, it is advantageous in that it is not necessary to coat an antiglare material. When the antiglare layer is a coating layer, it is advantageous in that the antiglare property can be easily controlled by selection of materials.

As a method for performing the chemical antiglare treatment, a frosted treatment can be exemplified. The polishing treatment can be performed, for example, by immersing a glass substrate as an object to be treated in a mixed solution of hydrogen fluoride and ammonium fluoride. As a method of performing the physical antiglare treatment, for example, blasting treatment in which crystalline silica powder, silicon carbide powder, or the like is sprayed onto the main surface of the glass substrate with compressed air; a method in which a brush to which crystalline silica powder, silicon carbide powder or the like is attached is wetted with water and wiped with the tool, and the like.

The surface of the antiglare layer preferably has a surface roughness (root mean square roughness, RMS) of 0.01 μm to 0.5 μm. The surface Roughness (RMS) of the surface of the antiglare layer is more preferably 0.01 μm to 0.3 μm, still more preferably 0.02 μm to 0.2 μm. By setting the surface Roughness (RMS) of the surface of the antiglare layer to the above range, the haze value of the protective glass 1 can be adjusted to 1% to 30%. The haze value was a value defined in JIS K7136 (2000).

By having an antireflection layer as the functional layer 3, reflection of light incident from the first main surface 21 side can be prevented, and mapping due to incident light can be prevented. As the antireflection layer, for example, the following antireflection layer can be cited.

(1) And an antireflection layer having a multilayer structure in which low refractive index layers having a relatively low refractive index and high refractive index layers having a relatively high refractive index are alternately laminated.

(2) An antireflection layer including a low refractive index layer having a refractive index lower than that of the chemically strengthened glass 2.

(1) The antireflection layer (a) preferably has a structure in which a high refractive index layer having a refractive index of 1.9 or more for light having a wavelength of 550nm and a low refractive index layer having a refractive index of 1.6 or less for light having a wavelength of 550nm are laminated. By providing the antireflection layer with a structure in which a high refractive index layer and a low refractive index layer are laminated, reflection of visible light can be prevented more reliably.

(1) The number of layers of the high refractive index layer and the low refractive index layer in the antireflection layer of (a) may be one, but may be two or more. When the chemically strengthened glass 2 includes one high refractive index layer and one low refractive index layer, the antireflection layer is preferably formed by sequentially laminating the high refractive index layer and the low refractive index layer on the first main surface 21 of the chemically strengthened glass. In the case where two or more high refractive index layers and two or more low refractive index layers are included, the antireflection layer is preferably a laminate in which the high refractive index layers and the low refractive index layers are alternately laminated. From the viewpoint of productivity, the laminate is preferably a laminate of two or more and eight or less layers as a whole, and more preferably a laminate of two or more and six or less layers. The layer may be added within a range that does not impair the optical characteristics. For example, to prevent Na diffusion from the glass plate, siO may be interposed between the glass and the first layer ₂ And (3) a film.

The material constituting the high refractive index layer and the low refractive index layer is not particularly limited, and may be selected in consideration of the degree of antireflection and productivity required. Examples of the material constituting the high refractive index layer include: niobium oxide (Nb) ₂ O ₅ ) Titanium oxide (TiO) ₂ ) Zirconium oxide (ZrO) ₂ ) Tantalum oxide (Ta) ₂ O ₅ ) Silicon nitride (SiN), etc. One or more selected from these materials may be preferably used. Examples of the material constituting the low refractive index layer include a material containing silicon oxide (particularly silicon dioxide SiO ₂ )、Alumina (Al) ₂ O ₃ ) Magnesium fluoride (MgF) ₂ ) And a material containing a mixed oxide of Si and Sn, a material containing a mixed oxide of Si and Zr, a material containing a mixed oxide of Si and Al, and the like. One or more selected from these materials may be preferably used.

In the antireflection layer of (2), the refractive index of the low refractive index layer is set according to the refractive index of the chemically strengthened glass 2, and is preferably 1.1 to 1.5, more preferably 1.1 to 1.4.

(2) The antireflection layer of (c) may be suitably formed by a method of directly forming an inorganic thin film on the surface, a method of performing surface treatment by etching or the like, a dry method, for example, a Chemical Vapor Deposition (CVD) method, a Physical Vapor Deposition (PVD) method, and particularly a vacuum vapor deposition method or a sputtering method which is one of the physical vapor deposition methods.

The thickness of the antireflection layer is preferably 90nm to 500nm. The thickness of the antireflection layer is preferably 90nm or more, since reflection of external light can be effectively suppressed.

The antireflection layer is preferably a of the reflection color of the protective glass with film in the CIE (International Commission on illumination) color difference formula ^* Is-6 to 1, b ^* Is-8 to 1.

When a of the antireflection layer ^* Is-6 to 1, b ^* In the case of-8 to 1, there is no fear that the antireflection layer is colored in a dangerous color (warning color), and the color of the antireflection layer can be prevented from becoming conspicuous.

In the case where the antireflection layer and the anti-fingerprint treatment layer 81 are directly formed on the glass without forming the antiglare layer, the surface roughness of the cover glass 1 measured on the surface of the antireflection treatment layer after the anti-fingerprint treatment layer 81 is removed by corona treatment or plasma treatment is preferably less than 1nm in terms of Ra. If the contact angle of water on the surface is about 20 ° or less, it can be judged that the fingerprint-preventing treatment layer is removed. By making the surface roughness Ra of the outermost surface from which the fingerprint-resistant treatment layer 81 is removed less than 1nm, high scratch resistance can be achieved. More preferably from 0.3nm to 0.6nm, particularly preferably from 0.3nm to 0.5nm.

The surface roughness Ra can be measured, for example, by using the DFM mode of the scanning probe microscope SPI3800N manufactured by Seiko Instruments.

As shown in fig. 4 (B), the cover glass 1 may have a light shielding layer 31 provided on the second main surface 22. The light shielding layer 31 is a layer that shields visible light, and specifically, for example, is a layer having a visual transmittance of 50% or less for light having a wavelength of 380nm to 780 nm. By providing the light shielding layer 31, the line on the display device side or the illumination light of the backlight can be hidden, and thus the leakage of the illumination light from the periphery of the display device can be prevented.

In order to improve the adhesion to the light shielding layer 31, the second main surface 22 provided with the light shielding layer 31 and the chamfer 24 may be subjected to a primer treatment, an etching treatment, or the like.

The method of providing the light shielding layer 31 is not particularly limited, and examples thereof include a method of providing a printing ink by a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, a screen coating method, an inkjet method, and the like. In view of the ease of controlling the difference in thickness, the screen coating method is preferable.

The ink used for the light shielding layer 31 may be inorganic or organic. The inorganic ink may be, for example, an ink containing a material selected from SiO ₂ 、ZnO、B ₂ O ₃ 、Bi ₂ O ₃ 、Li ₂ O、Na ₂ O and K ₂ One or more of O, cuO, al ₂ O ₃ 、ZrO ₂ 、SnO ₂ And CeO ₂ More than one kind of Fe ₂ O ₃ And TiO ₂ Is a composition of (a).

As the organic ink, various printing materials obtained by dissolving a resin in a solvent can be used. For example, at least one or more resins selected from the group consisting of acrylic resins, urethane resins, epoxy resins, polyester resins, polyamide resins, vinyl acetate resins, phenolic resins, olefins, ethylene-vinyl acetate copolymer resins, polyvinyl acetal resins, natural rubber, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, polyester polyols, polyether urethane polyols, and the like can be used as the resin. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents can be used. For example, alcohols such as isopropyl alcohol, methanol and ethanol may be used, esters such as ethyl acetate may be used, and ketones such as methyl ethyl ketone may be used. As the aromatic hydrocarbon solvent, toluene, xylene, solvosiso (registered trademark) 100, solvosiso (registered trademark) 150, and the like can be used, and as the aliphatic hydrocarbon solvent, hexane, and the like can be used. These are exemplified as examples, and various other printing materials may be used. The light shielding layer 31 of the resin can be formed by applying the organic printing material described above to the chemically strengthened glass 2 and then evaporating the solvent. The ink used for the light shielding layer 31 may be a thermosetting ink that can be cured by heating, or may be a UV curable ink, and is not particularly limited.

The ink used in the light shielding layer 31 may contain a colorant. As the colorant, for example, when the light shielding layer 31 is set to black, a black colorant such as carbon black may be used. Further, a colorant of an appropriate color may be used according to a desired color.

The light shielding layer 31 may be laminated only a desired number of times, and different inks may be used for each layer for the ink used in printing. The light shielding layer 31 may be printed not only on the second main surface 22 but also on the first main surface 21 and also on the end surface.

When the light shielding layer 31 is laminated only a desired number of times, each layer may use a different ink. For example, when the user views the cover glass 1 from the first main surface 21 side, if the light shielding layer 31 is to be seen as white, the first layer may be printed with white, and then the second layer may be printed with black. Thus, when the user views the light shielding layer 31 from the first main surface 21 side, the white light shielding layer 31 in which the so-called "transparent feeling" associated with the visibility of the rear surface of the light shielding layer 31 is suppressed can be formed.

The planar shape of the light shielding layer 31 is a frame shape in fig. 4, and the inner side of the frame may constitute the display area 4, but may be a line shape along one side of the second main surface 22, an L-shape along two consecutive sides, or two straight lines along two opposite sides. When the second main surface 22 has a polygonal shape other than a quadrangle, a circular shape, or an irregular shape, the light shielding layer 31 may have a frame shape corresponding to these shapes, a straight line shape along one side of the polygon, or an arc shape along a part of the circular shape.

In the case where the cover glass 1 is used for a display device, the light shielding layer 31 preferably has a color corresponding to a color in the case where the display device is not displaying. For example, when the color is black in the case of non-display, the light shielding layer 31 is preferably black.

In the case where the cover glass 1 has the light shielding layer 31, as shown in fig. 5, the light shielding layer 31 may have the opening portion 33, and the opening portion 33 preferably has the infrared ray transmitting layer 35 having higher infrared ray transmittance than the light shielding layer 31. By providing the opening 33 in a part of the light shielding layer 31 and providing the infrared ray transmitting layer 35, an infrared ray sensor can be provided on the back side of the light shielding layer 31, and the infrared ray transmitting layer 35 can be made inconspicuous.

The ink forming the infrared ray transmitting layer 35 may be inorganic or organic. The pigment contained in the inorganic ink may contain, for example, a pigment selected from SiO ₂ 、ZnO、B ₂ O ₃ 、Bi ₂ O ₃ 、Li ₂ O、Na ₂ O and K ₂ One or more of O, cuO, al ₂ O ₃ 、ZrO ₂ 、SnO ₂ And CeO ₂ More than one kind of Fe ₂ O ₃ And TiO ₂ Is a composition of (a).

As the organic ink, various printing materials obtained by dissolving a resin and a pigment in a solvent can be used. For example, at least one or more resins selected from the group consisting of acrylic resins, urethane resins, epoxy resins, polyester resins, polyamide resins, vinyl acetate resins, phenolic resins, olefins, ethylene-vinyl acetate copolymer resins, polyvinyl acetal resins, natural rubber, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, polyester polyols, polyether urethane polyols, and the like can be used as the resin. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents can be used. For example, alcohols such as isopropyl alcohol, methanol and ethanol may be used, esters such as ethyl acetate may be used, and ketones such as methyl ethyl ketone may be used. As the aromatic hydrocarbon solvent, toluene, xylene, solvosiso (registered trademark) 100, solvosiso (registered trademark) 150, and the like can be used, and as the aliphatic hydrocarbon solvent, hexane, and the like can be used. These are exemplified as examples, and various other printing materials may be used. The organic printing material is coated on the chemically strengthened glass 2, and then the solvent is evaporated, whereby the infrared ray transmitting layer 35 of the resin can be formed. The heat curable ink that can be cured by heating may be a UV curable ink, and is not particularly limited.

The ink used in the infrared ray transmitting layer 35 may contain a pigment. As the pigment, for example, in the case where the infrared ray transmitting layer 35 is set to black, a black pigment such as carbon black may be used. In addition, pigments of appropriate colors may be used according to the desired colors.

The content ratio of the pigment in the infrared ray transmitting layer 35 can be freely changed according to desired optical characteristics. The content ratio of the pigment to the total mass of the infrared ray transmitting layer 35 is preferably 0.01 to 10 mass%. The content ratio can be achieved by adjusting the content ratio of the infrared transmitting material to the entire mass of the ink.

The ink forming the infrared ray transmitting layer 35 contains a pigment having infrared ray transmitting ability in a photocurable resin or a thermosetting resin. As the pigment, any one of an inorganic pigment and an organic pigment can be used. Examples of the inorganic pigment include iron oxide, titanium oxide, and complex oxides. Examples of the organic pigment include metal complex pigments such as phthalocyanine pigments, anthraquinone pigments, and azo pigments. The color of the infrared ray transmitting layer 35 is preferably the same as that of the light shielding layer 31. In the case where the light shielding layer 31 is black, the infrared ray transmitting layer 35 is preferably black.

The method of forming the infrared ray transmitting layer 35 is not particularly limited, and examples thereof include: bar coating, reverse coating, gravure coating, die coating, roll coating, screen coating, inkjet. In consideration of the continuity of the production process, the same formation method as that of the light shielding layer 31 is preferable.

The cover glass 1 of the present invention can be used as a cover member for a display device such as a panel display, an in-vehicle information device, or a portable device, for example, such as a liquid crystal display. By using the cover glass 1 of the present invention for a display device cover, white turbidity when a touch sensor is used can be prevented while protecting a target object.

In addition, the cover glass 1 of the present invention can suppress electrification of the cover glass generated when peeling a laminate attached to the surface of the cover glass at the time of attaching a panel to the cover glass or the like, for example, in the case of manufacturing a panel display such as a liquid crystal display or an organic Electroluminescence (EL) display, an in-vehicle information device, or a portable device, and therefore can suppress foreign matter adsorption due to electrification.

An example of a display device having a cover glass 1 will be described with reference to fig. 6. Here, an in-cell IPS (In Plane Switching in-plane switching) liquid crystal display device is exemplified.

The display device 10 shown in fig. 6 has a frame 5. The frame 5 has a bottom portion 51, a side wall portion 52 intersecting the bottom portion 51, and an opening portion 53 facing the bottom portion 51. The liquid crystal module 6 is disposed in a space surrounded by the bottom portion 51 and the side wall portion 52. The liquid crystal module 6 includes a backlight 61 disposed on the bottom 51 side and a liquid crystal panel 62 (display panel) disposed on the backlight 61. The liquid crystal panel 62 has IPS liquid crystal, and is embedded in a liquid crystal element having a touch function.

In addition, the cover glass 1 is provided at the upper end of the frame 5 in such a manner that the second main surface 22 faces the liquid crystal module 6 side. The cover glass 1 is bonded to the frame 5 and the liquid crystal module 6 via an adhesive layer 7 provided on the upper end surfaces of the opening 53 and the side wall 52.

The adhesive layer 7 is preferably transparent and has a small refractive index difference from the chemically strengthened glass 2.

The adhesive layer 7 may be, for example, a layer containing a transparent resin obtained by curing a liquid curable resin composition. Examples of the curable resin composition include a photocurable resin composition and a thermosetting resin composition, and among them, a photocurable resin composition containing a curable compound and a photopolymerization initiator is preferable. The curable resin composition is applied by, for example, a die coating method, a roll coating method, or the like, to form a curable resin composition film.

The adhesive layer 7 may be an OCA film (OCA tape). In this case, the OCA film may be bonded to the second main surface 22 side of the cover glass 1.

The thickness of the adhesive layer 7 is preferably 5 μm or more and 400 μm or less, more preferably 50 μm or more and 200 μm or less. The storage shear elastic modulus of the adhesive layer 7 is preferably 5kPa to 5MPa, more preferably 1MPa to 5 MPa.

The order of assembly is not particularly limited in manufacturing the display device 10. For example, a structure in which the adhesive layer 7 is disposed on the cover glass 1 may be prepared in advance, disposed on the frame 5, and then the liquid crystal module 6 may be attached.

Examples

Next, an embodiment of the present invention will be described. The present invention is not limited to the following examples.

Protective glass having various characteristics was produced, and the charge amount and the degree of white turbidity when incorporated into the device were determined. The specific steps are as follows. Example 1 is an example, and examples 2 to 6 are comparative examples.

Example 1

First, raw materials were prepared as glass before chemical strengthening so as to form glass having a composition shown in example 1 in table 1, and melted to form a square block of about 110mm, followed by slow cooling to obtain a glass body. Then, cutting and cutting were performed so as to form a plate shape having a longitudinal direction of 100mm, a transverse direction of 100mm and a thickness of 0.7 mm.

Then, the glass is chemically strengthened. The conditions for chemical strengthening are as follows: the chemical strengthening was performed by immersing in 100 wt% sodium nitrate molten salt at 450 ℃ for 3 hours, and then immersing in 100 wt% potassium nitrate molten salt at 450 ℃ for 3 hours.

The reinforced glass was washed, and then a liquid obtained by diluting Afluid S-550 manufactured by Asahi Klin AC6000 manufactured by Asahi corporation to 0.1 mass% with a fluorine-containing solvent manufactured by Asahi Klin AC6000 manufactured by Asahi corporation was applied to the surface by a spray method to form an anti-fingerprint treatment layer as the anti-fingerprint treatment layer 81, thereby obtaining a cover glass of example 1. The film thickness of the anti-fingerprint treatment layer was 5nm.

The sum of the compositions (mol%) of the glasses in examples 1 to 6 in table 1 may be not 100, and this is the result of rounding the respective values, and has no particular influence on the calculation of the concentration described in the claims.

The following evaluation was performed on the produced cover glass of example 1.

<CS、DOL>

The stress distribution in the thickness direction of the glass was measured using a glass surface stress meter device (FSM-6000 LE) manufactured by the manufacturing company of the folded-back sheet and a measuring machine SLP1000 manufactured by the manufacturing company of the folded-back sheet to which scattered photoelastic was applied, and the stress value of the outermost surface was defined as the surface compressive stress CS. The depth of glass having a stress value of 0MPa in the interior of the glass was taken as the depth of compressive stress DOL.

<CT>

CT is approximately obtained by the relation ct= (cs×dol)/(t-2×dol).

< Friction Charge amount >

The frictional charge amount was measured by JIS L1094 using a frictional charge attenuation measuring device manufactured by intel corporation: 2014 (triboelectric damping method).

< white turbidity >

The obtained cover glass was assembled in an in-cell IPS liquid crystal display device, and the surface of the cover glass was touched with a finger in a state where the power was turned on, and the finger was moved back and forth 10 times at a distance of 10cm at a speed of 1 second back and forth, and the presence or absence of white turbidity was visually confirmed. The sample that developed white turbidity was judged as "present", and the sample that did not develop white turbidity was judged as "absent".

Example 2

A cover glass of example 2 was produced under the same conditions as in example 1 except that a glass having a composition shown in example 2 of table 1 was produced as a glass before chemical strengthening by a float method to obtain a glass plate of 0.7mm, and the glass plate was immersed in a molten salt of 100 wt% potassium nitrate at 420 ℃ for 8 hours to perform chemical strengthening.

Example 3

A cover glass of example 3 was produced under the same conditions as in example 1 except that the glass having the composition shown in example 3 of table 1 was used as the glass before chemical strengthening, and the glass was immersed in 100 wt% potassium nitrate molten salt at 425 ℃ for 6 hours to perform chemical strengthening.

Example 4

A cover glass of example 4 was produced under the same conditions as in example 1 except that the glass having the composition shown in example 4 of table 1 was used as the glass before chemical strengthening, and the glass was immersed in 100 wt% potassium nitrate molten salt at 425 ℃ for 6 hours to perform chemical strengthening.

Example 5

A protective glass of example 5 was produced under the same conditions as in example 1, except that the glass before chemical strengthening was prepared by preparing raw materials so as to form a glass having the composition shown in example 5 of table 1, melting the raw materials, immersing the glass in a 100 wt% sodium nitrate molten salt at 450 ℃ for 2 hours, and immersing the glass in a 100 wt% potassium nitrate molten salt at 425 ℃ for 1.5 hours, to thereby chemically strengthen the glass.

Example 6

A protective glass of example 6 was produced under the same conditions as in example 1 except that a glass having the composition shown in example 6 of table 1 was used as the chemically strengthened glass.

The above results are shown in table 1.

TABLE 1

As shown in Table 1, in example 1, the frictional charge was 0kV or less and-1.5 kV or more, the depth DOL of the compressive stress layer was 60 μm or more, and the molar number of Li was the largest among all the alkali metals contained in the tensile stress layer, and white turbidity was not generated.

In examples 2 to 4, DOL was less than 60. Mu.m, and therefore the impact resistance of the glass surface was poor, and the glass was not suitable as a cover glass.

In examples 4 to 6, the frictional electrification was less than-1.5 kV, and white turbidity was generated.

In example 1, CS was 800MPa to 1000MPa and CT was about 60MPa.

In example 1, a was 14.5 mol or more and a×b was 120 or more.

In example 1, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is 81 mol% or less.

From the above results, it was found that a protective glass having excellent impact resistance and capable of preventing white turbidity can be obtained by setting the frictional charge to 0kV or less and-1.5 kV or more, the depth DOL of the compressive stress layer to 60 μm or more, and the composition to be the maximum mole number of Li in all alkali metals contained in the tensile stress layer.

The invention has been described in detail with reference to specific modes, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The present application is based on japanese patent application filed on 2.16.2018 (japanese patent application publication No. 2018-26236), the entire contents of which are incorporated by reference. In addition, all references cited herein are incorporated herein by reference in their entirety.

Description of the reference numerals

1 … cover glass, 2 … chemically strengthened glass, 3 … functional layer, 4 … display area, 5 … frame, 6 … liquid crystal component, 7 … adhesive layer, 10 … display device, 21 … first major surface, 22 … second major surface, 23 … end face, 24 … chamfer portion, 25 … compressive stress layer, 27 … tensile stress layer, 31 … light shielding layer, 32 … compressive stress layer, 33 … opening portion, 35 … infrared transmission layer, 51 … bottom, 52 … side wall portion, 53 … opening portion, 61 … backlight source, 62 … liquid crystal panel, 81 … fingerprint preventing treatment layer.

Claims (10)

1. A protective glass is characterized in that,

the protective glass has:

a chemically strengthened glass having a first major face and a second major face; and

an anti-fingerprint treatment layer disposed on the first major face, and

in the chemically strengthened glass:

the molar number of Li is the largest among all alkali metals contained in the tensile stress layer,

the depth DOL of the compressive stress layer is 60 μm or more,

the thickness of the anti-fingerprint treatment layer is 2 nm-20 nm,

by JIS L1094:2014, wherein the frictional charge on the surface of the anti-fingerprint treatment layer is 0kV or less and-1.5 kV or more,

In the chemically strengthened glass:

li is added to the oxide component constituting the tensile stress layer ₂ O、Na ₂ O、K ₂ The total of the O concentrations is C mass%, al ₂ O ₃ When the concentration of (C) is set to D mass%, C is 11 or more, C×D is 140 or more, and

among oxide components constituting the tensile stress layer, al ₂ O ₃ The content of K is more than 10 mass percent ₂ The content of O is 0.1 mass% or more and 3 mass% or less, zrO ₂ The content of (2) is 3 mass% or less.

2. The cover glass according to claim 1, wherein,

in the chemically strengthened glass:

li is added to the oxide component constituting the tensile stress layer ₂ O、Na ₂ O、K ₂ The total of the O concentration was A mol%, al ₂ O ₃ When the concentration of (B) is set to B mol%, A is 14.5 or more, and A×B is 120 or moreAnd (3) upper part.

3. The cover glass according to claim 1 or 2, wherein,

in the chemically strengthened glass:

among the oxide components constituting the tensile stress layer, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is 81 mol% or less.

4. The cover glass according to claim 1 or 2, wherein,

in the chemically strengthened glass:

among the oxide components constituting the tensile stress layer, siO ₂ 、Al ₂ O ₃ 、B ₂ O ₃ 、P ₂ O ₅ The total concentration of (2) is 82 mass% or less.

5. The cover glass according to claim 1 or 2, wherein the cover glass has at least one of an antiglare functional layer or an antireflection layer provided between the chemically strengthened glass and the fingerprint-resistant treatment layer.

6. The cover glass according to claim 1 or 2, wherein the cover glass has a light shielding layer provided on the second main surface.

7. The protective glass according to claim 6, wherein,

the light shielding layer has an opening and

the opening portion is provided with an infrared ray transmitting layer having higher infrared ray transmittance than the light shielding layer.

8. The cover glass of claim 1 or 2, wherein the chemically strengthened glass is a bent glass.

9. The cover glass according to claim 1 or 2, wherein an antiglare layer is provided between the first main surface and the fingerprint-resistant treatment layer, and a surface roughness of the antiglare layer is represented by Ra of 0.01 μm to 0.5 μm.

10. An in-cell IPS liquid crystal display device, wherein the in-cell IPS liquid crystal display device has the protective glass according to any one of claims 1 to 9.

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