JP2021070590A - Cover glass and in-cell liquid-crystal display device - Google Patents

Abstract

To provide: a cover glass which can be prevented from becoming cloudy, without an increase in the thickness thereof and the number of steps for production thereof, and which also has superior impact resistance; and an in-cell liquid crystal display device.SOLUTION: The present invention pertains to a cover glass comprising: a chemically strengthened glass including a first main surface and a second main surface; and a fingerprint-resistant treatment layer provided on the first main surface, wherein of all alkali metals contained in a tensile stress layer of the chemically strengthened glass, the number of moles of Li is the largest, the depth DOL of a compressive stress layer is 60μ m or more, and the surface of the fingerprint-resistant treatment layer has a triboelectric charge amount of -1.5 to 0 kV.SELECTED DRAWING: Figure 1

Description

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

An electronic device having a liquid crystal display device such as a smartphone may be equipped with a touch function. The touch function referred to here is a function of inputting information by an operator touching or bringing a finger close to or in contact with a cover glass provided on the surface of the display device.
As a structure that realizes the touch function, there is an external type (out-cell type) in which a touch panel is attached to a liquid crystal display device.
The external type is excellent in yield because even if one of the liquid crystal display device and the touch panel is defective, the other can be used, but there is also a problem that the thickness and weight increase.
Therefore, an on-cell type liquid crystal display device in which a touch panel is sandwiched between a liquid crystal element of the liquid crystal display device and a polarizing plate has appeared.
Further, an in-cell type liquid crystal display device in which an element having a touch function is embedded in a liquid crystal element has been developed as a structure thinner and lighter than the on-cell type.

On the other hand, the in-cell type liquid crystal display device (particularly the IPS liquid crystal display device) has a problem that the liquid crystal screen is partially clouded due to charging when the cover glass is touched with a finger. This is because, in the external type and the on-cell type, the touch panel located on the operator side of the liquid crystal element contributes to static electricity elimination, while in the in-cell type liquid crystal display device, the touch panel is not arranged on the operator side of the liquid crystal element. Therefore, the liquid crystal element is easily charged by static electricity. In particular, layers for enhancing impact resistance and antifouling property may be formed on the surface of the cover glass, and if these layers are easily charged, white turbidity is more likely to occur.

Therefore, in an in-cell type liquid crystal display device, a structure has been proposed in which a conductive layer is provided on the operator side of the liquid crystal display device to release static electricity to prevent white turbidity (Patent Document 1).

International Publication No. 2014/069377

However, the structure of Patent Document 1 has a problem that the thickness is increased by providing the conductive layer. There is also a problem that the man-hours for manufacturing the display device increase.

The present invention has been made in view of the above problems, and is a cover glass that can prevent white turbidity without increasing the thickness and man-hours for manufacturing, and has excellent impact resistance, and an in-cell liquid crystal display device (in-cell type liquid crystal display device). In particular, the purpose is to provide an IPS liquid crystal display device).

The cover glass of the present invention includes a chemically strengthened glass having a first main surface and a second main surface, and an anti-fingerprint treatment layer provided on the first main surface of the chemically strengthened glass. Among all alkali metals contained in the tensile stress layer, the chemically strengthened glass has the largest number of moles of Li, the depth DOL of the compressive stress layer is 60 μm or more, and the amount of frictional charge on the surface of the anti-fingerprint layer is large. , JIS L1094: 2014, characterized in that it is 0 kV or less and −1.5 kV or more by the D method.

According to the present invention, since the amount of triboelectric charge on the surface of the anti-fingerprint treatment layer is 0 kV or less and -1.5 kV or more, it is difficult for triboelectric charge even if a user's finger or the like comes into contact with the surface, and the display device can be used. When incorporated, it is possible to prevent white turbidity due to static electricity.
Further, according to the present invention, since triboelectric charging is suppressed by the physical characteristics of the cover glass, it is not necessary to provide a conductive layer, and white turbidity can be prevented without increasing the thickness and man-hours.
Further, according to the present invention, the chemically strengthened glass has the largest number of moles of Li among all alkali metals contained in the tensile stress layer. Therefore, the compressive stress layer can contain a larger amount of K and Na having a larger ionic radius than Li at the time of chemical strengthening, and the surface compressive stress of the compressive stress layer can be increased.
According to 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, the deformation due to the impact is not easily transmitted to the tensile stress layer, and the impact resistance Can be enhanced.

In the present invention, in the chemically strengthened glass, _{the total concentration of Li 2} O, Na ₂ O, and K ₂ O among the oxide components constituting the tensile stress layer is A mol%, and the concentration of Al ₂ O ₃ is B. In terms of mol%, it is preferable that A is 14.5 or more and A × B is 120 or more.
Alternatively, when the total concentration of _{Li 2} O, Na ₂ O, and K ₂ O among the oxide components constituting the tensile stress layer is _{C mass% and the concentration of Al 2} O ₃ is D mass%, C is It is preferable that the value is 11 or more and C × D is 140 or more.
_{According to the present invention, since Li 2} O, Na ₂ O, and K ₂ O, which do not contribute to the formation of the skeleton of glass and have high mobility and perform static electricity elimination in combination with static electricity, are contained in a certain amount or more, the user's finger is on the surface. It is more difficult to be triboelectrically charged even if they come into contact with each other.
Further, according to the present invention, since _{Al 2} O ₃ which contributes to skeleton formation and tends to be close to _{Li 2} O, Na ₂ O and K ₂ O is also contained in a certain amount or more, Li ₂ O and Na ₂ O are contained. , K ₂ O penetrates between the skeletons formed by _{Al 2} O _{3 to extend the distance.} Therefore, Li ₂ O, Na ₂ O, and K ₂ O are more easily moved, and even if the user's finger or the like comes into contact with the surface, triboelectric charging is less likely to occur.

In the present invention, the chemically strengthened glass has _{a total concentration of SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer of 81 mol% or less. Is preferable.
Alternatively, it is preferable that the total concentration of _{SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer is 82% by mass or less.
In the present invention, since it contributes to the formation of the skeleton of glass, the concentrations of _{SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O _{5 which} have low mobility and have a weak action of removing static electricity in combination with static electricity. Is suppressed below a certain level. Therefore, even if the user's finger or the like comes into contact with the surface, triboelectric charging is less likely to occur.

In the present invention, the cover glass preferably includes at least one of an antiglare function layer and an antireflection layer provided between the chemically strengthened glass and the anti-fingerprint treatment layer.
In the present invention, when the cover glass is provided with the antiglare function layer, the incident light can be scattered and the reflection due to the incident light can be blurred. When the antireflection layer is provided, the reflection of the incident light can be prevented, and the reflection due to the incident light can be prevented.

In the present invention, it is preferable to provide a light-shielding layer provided on the second main surface.
According to the present invention, since the light-shielding layer is provided on the second main surface, when the cover glass is incorporated into the display device, the wiring on the display device side is concealed or the illumination light of the backlight is concealed. , It is possible to prevent the illumination light from leaking from the surroundings of the display device.

In the present invention, the light-shielding layer preferably has an opening, and the opening is preferably provided with an infrared-transmitting layer having an infrared transmittance higher than that of the light-shielding layer.
According to the present invention, since the light-shielding layer is provided with the infrared-transmitting layer, the infrared sensor can be provided on the back side of the light-shielding layer when the cover glass is incorporated in the display device having the infrared sensor, and the infrared-transmitting is transmitted. You can make the layers inconspicuous.

In the present invention, the chemically strengthened glass is preferably bent glass.
According to the present invention, since the chemically strengthened glass is bent glass, there is no possibility that the mounting accuracy will be lowered even if the mating member to which the cover glass is attached has a bent shape.

In the present invention, when the antiglare layer is provided, the surface roughness measured on the surface of the anti-fingerprint treatment layer on the outermost surface is preferably 0.01 μm to 0.5 μm in Ra.
According to the present invention, in the case of a cover glass having an antiglare layer, the surface roughness measured on the surface of the anti-fingerprint treatment layer is 0.01 μm to 0.5 μm in Ra, so that while preventing charging. , Visibility can be ensured.
In the present specification, "a to b" represent a lower limit value a and an upper limit value b, and are interpreted to include "lower limit value a and upper limit value b", respectively.

The in-cell liquid crystal display device of the present invention is characterized by including any of the above-mentioned cover glasses.
According to the present invention, an in-cell liquid crystal display device protected by a cover glass can be obtained.

Sectional drawing of the cover glass which concerns on one Embodiment of this invention. Sectional drawing of the cover glass which concerns on a modification. Sectional drawing of the cover glass which concerns on a modification. (A) is a perspective view of the cover glass according to the modified example, and (B) is a sectional view taken along line BB of (A). Sectional drawing of the cover glass which concerns on a modification. FIG. 3 is a partial cross-sectional view of a display device including a cover glass according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Composition of cover glass]
First, the configuration of the cover glass will be described.
The cover glass 1 shown in FIG. 1 includes a chemically strengthened glass 2 and an anti-fingerprint processing layer 81.

The chemically strengthened glass 2 is rectangular in a plan view and transmits visible light. The chemically strengthened glass 2 includes a first main surface 21, a second main surface 22, and an end surface 23. A chamfered portion 24 is provided on the end surface 23.

The chemically strengthened glass 2 includes compressive stress layers 25 and 32 and tensile stress layers 27. The compressive stress layers 25 and 32 are layers on which compressive stress acts (layers having a compressive stress of 0 MPa 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 is also provided on the end face 23, but description thereof will be omitted here.
The tensile stress layer 27 is a layer on which tensile stress acts (a layer having a compressive stress of less than 0 MPa). The tensile stress layer 27 is provided between the compressive stress layer 25 and the compressive stress layer 32.

The chemically strengthened glass 2 has the largest number of moles of Li among all the alkali metals contained in the tensile stress layer 27. Since the composition has the largest number of moles of Li, the compressive stress layers 25 and 32 can contain a larger amount of K and Na having an ionic radius larger than that of Li at the time of chemical strengthening. The number of moles of Li is more preferably 0.5 times or more, still more preferably 0.8 or more with respect to the number of moles of Na.

The chemically strengthened glass 2 has a depth DOL (Depth of Layer) of 60 μm or more at the compressive stress layers 25 and 32. When the DOL is 60 μm or more, when an impact is applied from the outside, the 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.
More preferably, the DOL is 80 μm to 250 μm.
The DOL theoretically means the depth from the surface to the position where the compressive stress is 0 MPa in the plate thickness direction, but is alkali in the depth direction of the glass by EPMA (electron probe microanalyzer, electron probe microanalyzer). Ion concentration analysis (in this example, concentration analysis of ions diffused by chemical strengthening) can be performed, and the ion diffusion depth obtained by the measurement can be regarded as DOL. DOL can also be measured using a surface stress meter (for example, FSM-6000 manufactured by Orihara Seisakusho) or the like.

_{In the chemically strengthened glass 2, the total concentration of Li 2} O, Na ₂ O, and K ₂ O among the oxide components constituting the tensile stress layer was A mol%, and the concentration of Al ₂ O ₃ was B mol%. At that time, it is preferable that A is 14.5 or more and A × B is 120 or more. More preferably, A is 15 to 20 and A × B is 170 to 300.

When A is expressed by mass (C mass%), it is preferably 11 or more, preferably 12 to 20, although it _{depends on the molar ratio of each component to the total of Li 2} O, Na ₂ O, and K _{2 O.} More preferred.
When A × B is expressed by mass (C mass% × D mass%), 140 or more is preferable, although it depends on the molar ratio of each component to the total of _{Li 2} O, Na ₂ O, and K _{2 O.} 150-400 is more preferable.
The reason is as follows.

The components that make up glass can be broadly divided into components that contribute to the formation of the skeleton of glass (also called network formers) and components that do not contribute to the formation of the skeleton.
Of these, from the viewpoint of preventing charging, it is preferable that there are many components that do not contribute to skeleton formation. This is because the components that do not contribute to skeleton formation have higher mobility than the components that contribute to skeleton formation, and are therefore considered to be combined with static electricity to eliminate static electricity. Since Li ₂ O, Na ₂ O, and K ₂ O are components that do not contribute to skeleton formation in glass, a large amount is preferable. This is the basis for defining A.
In addition, Al ₂ O ₃ behaves as a component that contributes to skeleton formation or as a component that does not contribute to skeleton formation. When contributing to skeleton formation, it tends to be close to _{Li 2} O, Na ₂ O, and K _{2 O.} In close proximity, Li ₂ O, Na ₂ O, and K ₂ O enter between the components that form the skeleton, increasing the distance between the skeletons. Increasing the distance between skeletons is preferable because components that do not contribute to skeleton formation can easily move between skeletons and the mobility increases. This is the reason for defining AxB.

Triboelectric charging is a phenomenon that occurs on the surface of the compressive stress layer 25, and the reason for defining a preferable composition of the tensile stress layer 27 is as follows.
Since it is the skeleton of the glass that affects triboelectric charging, it is desirable to define the structure of the glass. However, since glass is amorphous and it may be difficult to specify the structure, it is preferable to specify the composition. On the other hand, since the compressive stress layer 25 is ion-exchanged by chemical strengthening, the composition is different from that of the tensile stress layer 27, but the glass network structure 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 will be different, so that it is difficult to specify the structure of the compressive stress layer 25 by the composition of the compressive stress layer 25. Therefore, by specifying the composition of the tensile stress layer 27, the structure of the tensile stress layer 27 is specified, and the structures of the tensile stress layer 27 and the compressive stress layer 25 do not change even if they are chemically strengthened. The structure of the compressive stress layer 25 is specified from the composition of the stress layer 27.

_{In the chemically strengthened glass 2, the total concentration of SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer 27 is preferably 81 mol% or less. .. This is because these elements are components that contribute to the formation of the skeleton of glass, and the smaller the content, the greater the components that contribute to static elimination. Further, the smaller the content, the wider the distance between the components forming the skeleton, and the higher the mobility of the components that do not contribute to the skeleton formation.
Triboelectric charging is a phenomenon that occurs on the surface of the compressive stress layer 25, but the reason for defining the preferable composition of the tensile stress layer is the same as the reason for defining A and B.

When _{the total concentration of SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ is expressed in mass%, it is 82% by mass or less, although it depends on the molar ratio of each component to the total. It is preferably 70% by mass to 81% by mass, more preferably.

As a more specific composition of the tensile stress layer 27, in terms of mass percentage display based on oxide, SiO ₂ is 55% to 68%, Al ₂ O ₃ is 10% to 25%, and B ₂ O ₃ is 0% to 0%. 5%, P ₂ O ₅ 0% -15%, Li ₂ O 0% -8%, Na ₂ O 1% -20%, K ₂ O 0.1% -10%, Mg O 0% 10%, CaO 0% -5%, SrO 0% -5%, BaO 0% -5%, ZnO 0% -5%, TiO ₂ 0% -1%, ZrO ₂ 0% A glass composition containing ~ 5% and 0.005% to 0.1% of _{Fe 2} O _{3 is preferable.}
The composition of the tensile stress layer 27 can be quantified by a known composition analysis method such as chemical analysis, absorptiometry, atomic absorption spectroscopy, and fluorescent X-ray analysis. The measurement position is an arbitrary position of the tensile stress layer 27, but a center position in the thickness direction of the glass substrate and a position of the center of gravity on a plane are preferable.

Each component in the preferable glass composition of the above-mentioned tensile stress layer 27 is exemplified below.

SiO ₂ is a component that constitutes the skeleton of glass. In addition, it is a component that increases chemical durability and reduces the occurrence of cracks when the glass surface is scratched (indented). In order to suppress the occurrence of cracks, the SiO ₂ content is preferably 55% or more, more preferably 56% or more, further preferably 56.5% or more, and particularly preferably 58% or more. On the other hand, in order to improve the mobility of the element contributing to static elimination in the glass and to improve the meltability in the glass manufacturing process, the SiO ₂ content is preferably 68% or less, more preferably 65% or less. It is more preferably 63% or less, and particularly preferably 61% or less.

Al ₂ O ₃ is an effective component for improving the ion exchange performance during the chemical strengthening treatment and increasing the surface compressive stress CS after the chemical strengthening. It also has the effect of improving the fracture toughness value of glass. It is also a component that increases the Tg of glass and is also a component that increases Young's modulus. It also has the effect of improving the mobility of elements that contribute to static elimination in glass. In order to enhance these properties, the Al ₂ O ₃ content is preferably 10% or more, more preferably 12% or more. Further, in order to increase the fracture toughness value, 14% or more is more preferable. On the other hand, from the viewpoint of increasing the content of elements contributing to static elimination in the glass and from the viewpoint of maintaining the acid resistance of the glass and lowering the devitrification temperature, _{the content of Al 2} O ₃ is preferably 25. % Or less, more preferably 23% or less.

Al ₂ O ₃ is a constituent of lithium aluminosilicate crystals. In order to suppress crystal precipitation during bending, _{the content of Al 2} O ₃ is preferably 22% or less, more preferably 20% or less, still more preferably 19% or less.

B ₂ O ₃ is a component that improves the meltability of glass. It is also a component that improves the chipping resistance of glass. B ₂ O ₃ is not essential, but the content when it is contained is preferably 0.1% or more, more preferably 0.5% or more, still more preferably 1% or more in order to improve the meltability. is there. On the other hand, from the viewpoint of improving the mobility of the elements that contribute to static elimination in the glass and from the viewpoint of preventing the occurrence of veins during melting, _{the content of B 2} O ₃ is preferably 5% or less. It is preferably 4% or less, more preferably 3% or less, and particularly preferably 2.5% or less.

P ₂ O ₅ is a component that improves ion exchange performance and chipping resistance during chemical strengthening treatment. Although P ₂ O ₅ is not essential, the content when it is contained is preferably 0.1% or more, more preferably 1% or more, still more preferably 2% or more. On the other hand, in order to secure acid resistance and prevent charging, it is preferably 15% or less, more preferably 10% or less, further preferably 8% or less, further preferably 6% or less, and particularly preferably 4% or less. is there.

Li ₂ O is a component that forms a surface compressive stress layer by chemical strengthening treatment with a sodium salt such as sodium nitrate. It is also a substance that contributes to static elimination in glass.
The content of Li ₂ O is preferably 0.1% or more, more preferably 1% or more, still more preferably 2% or more in order to obtain the effect of containing it. On the other hand, from the viewpoint of ensuring weather resistance, 8% or less is preferable. Further, in order to suppress crystal precipitation during bending molding, 7% or less is preferable, and 6% or less is more preferable.

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. It is also a substance that contributes to static elimination in glass.
In order to obtain the effect, _{the content of Na 2} O is preferably 1% or more, more preferably 1.5% or more, still more preferably 2% or more. On the other hand, in order to improve the surface compressive stress CS, 20% or less is preferable, 16% or less is more preferable, 14% or less is further preferable, and 8% or less is particularly preferable.

K ₂ O is a substance that improves the meltability of glass. It is also a substance that contributes to static elimination in glass. When K ₂ O is contained, the content is preferably 0.1% or more, more preferably 0.5% or more. On the other hand, from the viewpoint of ensuring the crushability of the chemically strengthened glass, the K ₂ O content is preferably 8% or less, more preferably 5% or less, still more preferably 3% or less.

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

CaO is not essential, but it is a component that improves the meltability of glass and may be contained. When CaO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more, still more preferably 0.15% or more. On the other hand, from the viewpoint of ensuring the ion exchange performance during the chemical strengthening treatment, 5% or less is preferable, 2% or less is more preferable, and 1.5% or less is further preferable.

Although SrO is not essential, it is a component that improves the meltability of glass and may be contained. The content when contained is preferably 0.05% or more, more preferably 0.1% or more, still more preferably 0.5% or more. On the other hand, in order to improve the ion exchange performance during the chemical strengthening treatment, the SrO content is preferably 5% or less, more preferably 3.5% or less, further preferably 2% or less, and substantially not contained. Especially preferable.

BaO is a component that improves the meltability of glass, although it is not essential, and may be contained. The content when contained is preferably 0.1% or more, more preferably 0.5% or more, still more preferably 1% or more. On the other hand, in order to improve the ion exchange performance during the chemical strengthening treatment, the BaO content is preferably 5% or less, more preferably 3% or less, further preferably 2% or less, and further preferably substantially not contained. ..

ZnO is a component that improves 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 increased, which is preferable. The content of ZnO is more preferably 3% or less, further preferably 1% or less, and it is particularly preferable that the ZnO content is substantially not contained.

TiO ₂ is a component that suppresses a change in the color tone of glass due to solarization, and may be contained. When TiO ₂ is contained, the content is preferably 0.01% or more, more 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, it is preferably 1% or less, more preferably 0.5% or less, still more preferably 0.2% or less.

ZrO ₂ is a component that increases the surface compressive stress CS due to ion exchange during the chemical strengthening treatment, and may be contained. When these are contained, the content is preferably 0.1% or more, more preferably 0.5% or more, still more preferably 1% or more. On the other hand, in order to suppress devitrification during melting and improve the quality of the chemically strengthened glass, it is preferably 5% or less, more preferably 3% or less, and particularly preferably 2.5% or less.

Since Fe ₂ O ₃ absorbs heat rays, it has the effect of improving the solubility of glass, and is preferably contained when glass is mass-produced using a large melting kiln. In that case, the content is preferably 0.005% or more, more preferably 0.006% or more, still more preferably 0.007% or more. On the other hand, if it is contained in an excessive amount, coloring occurs. Therefore, in order to increase the transparency of the glass, 0.1% or less is preferable, 0.05% or less is more preferable, 0.02% or less is more preferable, and 0 is particularly preferable. It is less than .015%.
Although all the iron oxides in the glass _{have been described as Fe 2} O ₃ here, in reality, Fe (III) in the oxidized state and Fe (II) in the reduced state are usually mixed. .. Of these, Fe (III) produces yellow coloring, Fe (II) produces blue coloring, and the balance between the two produces green coloring in the glass.

Y ₂ O ₃ , La ₂ O ₃ , and Nb ₂ O ₅ may be contained. When these components are contained, the total content is preferably 0.01% or more, more preferably 0.05% or more, still more preferably 0.1% or more, and particularly preferably 0.15. % Or more, most preferably 1% or more. On the other hand, _{if the contents of Y 2} O ₃ , La ₂ O ₃ , and Nb ₂ O ₅ are too large, the glass tends to be devitrified at the time of melting, and the quality of the chemically strengthened glass may deteriorate. The total amount is preferably 7% or less. The total content of Y ₂ O ₃ , La ₂ O ₃ , and Nb ₂ O ₅ is more preferably 6% or less, further preferably 5% or less, particularly preferably 4% or less, and most preferably 3.5. % Or less.

Ta ₂ O ₅ and Gd ₂ O ₃ may be contained in a small amount in order to improve the crushability of the chemically strengthened glass, but 5% or less is preferable and 2% or less is more preferable because the refractive index and reflectance are high. It is preferable, and it is more preferable that it is not contained.

Further, when coloring the glass, a coloring component may be added as long as the achievement of the desired chemical strengthening property is not hindered. Examples of the coloring component include 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. Is mentioned as a suitable one.
It is preferable that the total content of the coloring components is 7% or less because problems such as devitrification are unlikely to occur. This content is preferably 5% or less, more preferably 3% or less, still more preferably 2% or less. When giving priority to the visible light transmittance of glass, it is preferable that these components are not substantially contained.

_{SO 3} , chloride, fluoride and the like may be appropriately contained as a fining agent when melting glass. As ₂ O ₃ has a large environmental load, so it is preferable not to contain it. When Sb ₂ O ₃ is contained, it is preferably 1% or less, more preferably 0.5% or less, and most preferably not contained.

The chemically strengthened glass 2 preferably has a surface compressive stress CS of 300 MPa to 1500 MPa.
When it is 300 MPa or more, the bending strength required for the cover glass can be maintained. When it is 1500 MPa or less, it is possible to prevent it from being scattered into pieces when it is cracked. More preferably, it is 800 MPa to 1200 MPa.
The surface compressive stress CS here means the compressive stress on the outermost surface of the glass. The surface compressive stress CS can be measured using a surface stress meter (for example, FSM-6000 manufactured by Orihara Seisakusho) or the like.

The chemically strengthened glass 2 preferably has an internal tensile stress CT of 20 MPa to 100 MPa.
When it is 20 MPa or more, it is possible to achieve a state in which the compressive stress existing as a reaction has an appropriate stress value and depth. When it is 100 MPa or less, it can be prevented from being scattered into pieces when it is cracked. More preferably, it is 40 MPa to 85 MPa.
The internal tensile stress CT is approximately obtained by the relational expression CT = (CS × DOL) / (t-2 × DOL), where t is the thickness of the cover glass 1.

The anti-fingerprint processing layer 81 is a layer that reduces the adhesion of stains due to fingerprints, sebum, sweat, etc. when a human finger touches the second main surface 22.

The constituent material of the fingerprint prevention treatment layer 81 can be appropriately selected from a fluorine-containing organic compound and the like that can impart antifouling property, water repellency, and oil repellency. Specific examples thereof include a fluorine-containing organosilicon compound and a fluorine-containing hydrolyzable compound. The fluorine-containing organic compound can be used without particular limitation as long as it can impart antifouling property, water repellency and oil repellency.
The fluorine-containing organic compound originally has a property of being easily charged when touched with a finger when formed on chemically strengthened glass, but in the present embodiment, the triboelectric amount on the surface of the fingerprint prevention treatment layer 81 is 0 kV. Hereinafter, since it is −1.5 kV or more, charging can be suppressed.

The fluorine-containing organosilicon compound coating forming the anti-fingerprint treatment layer 81 is formed on the surface of the antireflection layer when the antireflection layer is formed on the main surface of the transparent substrate or the treatment surface of the antiglare layer. Is preferable. Further, when a glass substrate that has been subjected to surface treatment such as antiglare treatment or chemical strengthening treatment as the transparent substrate and does not form an antireflection layer is used, the fluorine-containing organosilicon compound coating is the surface to which these surface treatments have been applied. It is preferably formed directly on.

In the anti-fingerprint treatment layer 81, the fluorine-containing organosilicon compound film used for forming the fluorine-containing organosilicon compound film is such that the obtained fluorine-containing organosilicon compound film has antifouling properties such as water repellency and oil repellency. If there is, there is no particular limitation. Specific examples thereof include a fluorine-containing hydrolyzable silicon compound having one or more groups selected from the group consisting of a perfluoropolyether group, a perfluoroalkylene group, and a perfluoroalkyl group.

The layer thickness of the anti-fingerprint treatment layer 81 is not particularly limited, but is preferably 2 nm to 20 nm, more preferably 2 nm to 15 nm, and even more preferably 3 nm to 10 nm. When the layer thickness is 2 nm or more, the surface of the antireflection layer is uniformly covered by the anti-fingerprint treatment layer 81, and the anti-fingerprint property and the anti-scratch property can be put into practical use. Further, when the layer thickness is 20 nm or less, the optical characteristics such as the visual reflectance and the haze value in the state where the fingerprint prevention processing layer 81 is laminated are good.

The cover glass 1 has a triboelectric charge amount of 0 kV or less and −1.5 kV or more on the surface of the anti-fingerprint treatment layer 81. The triboelectric charge amount referred to here means the triboelectric charge amount obtained by the D method (triboelectric attenuation measurement method) described in JIS L1094: 2014. The fluorine-based anti-fingerprint treatment layer is negatively charged in the above evaluation method, but can be prevented from being charged when it is −1.5 kV or higher.
More preferably, it is 0 kV to -1 kV.
The above is the description of the configuration of the cover glass 1.

[Manufacturing method of cover glass 1]
Next, an example of a method for manufacturing the cover glass 1 will be described.

First, the chemically strengthened glass 2 is manufactured.
The chemically strengthened glass 2 is produced by chemically strengthening glass for chemically strengthening produced by a general glass manufacturing method.
The chemical strengthening treatment is a treatment in which the surface of glass is subjected to an ion exchange treatment to form a surface layer having compressive stress. Specifically, the ion exchange treatment is performed at a temperature below the glass transition point of the chemically strengthened glass, and metal ions (typically Li ions or Na ions) having a small ionic radius existing near the surface of the glass plate are transferred. Substitute with ions having a larger ionic radius (typically Na or K ions for Li ions and K ions for Na ions).

The present tempered glass can be produced, for example, by chemically strengthening the chemically strengthened glass having the composition of the above-mentioned tensile stress layer 27.
The following manufacturing method is an example of manufacturing a plate-shaped chemically strengthened glass.

First, the glass raw material is prepared and heated and melted in a glass melting kiln. Then, the glass is homogenized by bubbling, stirring, addition of a fining agent, etc., molded into a glass plate having a predetermined thickness by a conventionally known molding method, and slowly cooled. Alternatively, it may be formed into a plate shape by a method of forming it into a block shape, slowly cooling it, and then cutting it.

Examples of the method for forming into a plate shape include a float method, a press method, a fusion method and a down draw method. In particular, when producing a large glass plate, the float method is preferable. Further, continuous molding methods other than the float method, for example, the fusion method and the down draw method are also preferable.

Then, the formed glass is cut into a predetermined size and chamfered. It is preferable to perform chamfering so that the size of the chamfered portion 24 in a plan view is 0.05 mm or more and 0.5 mm or less.

Next, the glass plate is chemically strengthened by ion exchange treatment about once or twice (about one or two steps) to form compressive stress layers 25 and 32 and tensile stress layers 27.
In the chemical strengthening step, the glass to be treated is subjected to a molten salt (for example, potassium salt, etc.) containing an alkali metal ion having an ionic radius larger than that of the alkali metal ion (for example, sodium ion or lithium ion) contained in the glass. Alternatively, the sodium salt) is brought into contact with the glass in a temperature range not exceeding the transition temperature of the glass.

The alkali metal ions in the glass and the alkali metal salt having a large ionic radius of the alkali metal salt are ion-exchanged to generate compressive stress on the glass surface due to the difference in the occupied area of the alkali metal ions to form a compressive stress layer. To do. The temperature range in which the glass is brought into contact with the molten salt may be a temperature range that does not exceed the transition temperature of the glass, but is preferably 50 ° C. or lower from the glass transition point. This prevents stress relaxation of the glass.

In the chemical strengthening treatment, the treatment temperature and the treatment time for bringing the glass into contact with the molten salt containing alkali metal ions can be appropriately adjusted according to the composition of the glass and the molten salt. The heating temperature of the molten salt is usually preferably 350 ° C. or higher, more preferably 370 ° C. or higher. Further, usually 500 ° C. or lower is preferable, and 450 ° C. or lower is more preferable.

By setting the heating temperature of the molten salt to 350 ° C. or higher, it is possible to prevent chemical fortification from becoming difficult due to a decrease in the ion exchange rate. Further, the decomposition / deterioration of the molten salt can be suppressed by setting the temperature to 500 ° C. or lower.

The treatment time for bringing the glass into contact with the molten salt is usually preferably 10 minutes or more, and more preferably 15 minutes or more in order to apply sufficient compressive stress. Further, in ion exchange for a long time, the productivity is lowered and the compressive stress value is lowered due to relaxation. Therefore, it is usually 20 hours or less, preferably 16 hours or less.

The number of times of chemical strengthening is exemplified once or twice, 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. It may be strengthened three times or more. In addition, a heat treatment step may be performed between the two strengthenings. In the following description, the case where the chemical strengthening is performed three times and the case where the heat treatment step is performed between the two times of strengthening are referred to as three-step strengthening.
In the case of three stages, it can be produced by using, for example, the strengthening treatment method 1 or the strengthening treatment method 2 described below.

(Strengthening processing method 1)
In the strengthening treatment method 1, first, a metal salt containing sodium (Na) ions (first metal salt) is brought into contact with a chemically strengthening glass containing _{Li 2 O to obtain Na ions in the metal salt.} Causes ion exchange with Li ions in the glass. Hereinafter, this ion exchange treatment may be referred to as "first stage treatment".
In the first-stage treatment, for example, chemically strengthened glass is immersed in a metal salt containing Na ions (for example, sodium nitrate) at about 350 ° C. to 500 ° C. for about 0.1 to 24 hours. In order to improve the productivity, the treatment time of the first stage is preferably 12 hours or less, more preferably 6 hours or less.

By the first-stage treatment, a deep compressive stress layer is formed on the glass surface, and a stress profile can be formed such that the CS is 200 MPa or more and the compressive stress depth DOL is 1/8 or more of the plate thickness. Further, the glass at the stage where the first stage treatment is completed has a large internal tensile stress CT, and therefore has a high crushability. However, it is rather preferable that the CT at this stage is large, because the crushability is improved by the subsequent treatment. The internal tensile stress CT of the glass after the first-stage treatment is preferably 90 MPa or more, more preferably 100 MPa or more, still more preferably 110 MPa or more. This is because the surface compressive stress CS of the compressive stress layer 25 becomes large.

The first metal salt is an alkali metal salt, and the alkali metal ion contains the largest amount of Na ion. Although Li ions may be contained, Li ions are preferably 2% or less, more preferably 1% or less, still more preferably 0.2% or less, based on 100% of the number of moles of alkaline ions. It may also contain K ions. With respect to 100% of the number of moles of alkaline ions contained in the first metal salt, K ions are preferably 20% or less, more preferably 5% or less.

Next, the metal salt containing lithium (Li) ions (second metal salt) is brought into contact with the glass after the first stage treatment, and the Li ions in the metal salt and the Na ions in the glass are ionized. The exchange reduces the compressive stress value near the surface layer. This process may be referred to as "second stage process".
Specifically, for example, it is immersed in a metal salt containing Na and Li at about 350 ° C. to 500 ° C. (for example, a mixed salt of sodium nitrate and lithium nitrate) for about 0.1 to 24 hours. In order to improve the productivity, the treatment time of the second stage is preferably 12 hours or less, more preferably 6 hours or less.

The glass after the second stage treatment can reduce the internal tensile stress, and when it breaks, it does not break violently.

The second metal salt is an alkali metal salt, and preferably contains Na ion and Li ion as alkali metal ions. Also, nitrates are preferred. The total number of moles of Na ion and Li ion is preferably 50% or more, more preferably 70% or more, and further 80% or more, based on 100% of the number of moles of alkali metal ions contained in the second metal salt. preferable. By adjusting the Na / Li molar ratio, the stress profile 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, but is preferably 0.3 or more, more preferably 0.5 or more, and more preferably 1 or more. In order to increase the compressive stress value of the compressive stress layer while reducing the CT, it is preferably 100 or less, more preferably 60 or less, and further preferably 40 or less.

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

Next, the metal salt containing potassium (K) ions (third metal salt) is brought into contact with the glass after the second stage treatment, and ion exchange between K ions in the metal salt and Na ions in the glass is performed. Causes a large compressive stress to be generated on the glass surface. This ion exchange treatment may be referred to as a "third stage treatment".
Specifically, for example, it is immersed in a metal salt (for example, potassium nitrate) containing K ions at about 350 ° C. to 500 ° C. for about 0.1 to 10 hours. By this process, a large compressive stress can be formed in a region of about 0 μm to 10 μm on the glass surface layer.

Since the third-stage treatment increases only the compressive stress of the shallow portion of the glass surface and has almost no effect on the inside, a large compressive stress can be formed on the surface layer while suppressing the tensile stress inside.
The third metal salt is an alkali metal salt and may contain Li ions as alkali metal ions, but Li ions are preferably 2% or less, more preferably 1% or less, based on 100% of the number of atoms of the alkali metal. , 0.2% or less is more preferable. 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 treatment time of the first to third stages can be set to 24 hours or less, which is preferable because of high productivity. The total processing time is more preferably 15 hours or less, further preferably 10 hours or less.

(Strengthening processing method 2)
In the strengthening treatment method 2, first, the first metal salt containing sodium (Na) ions is brought into contact with a chemically strengthening glass containing _{Li 2 O, and Na ions in the metal salt and Li in the glass are brought into contact with each other.} The first step of processing is performed to cause ion exchange with ions.
Since the first-stage processing is the same as in the case of the strengthening processing method 1, the description thereof will be omitted.

Next, the glass after the first stage treatment is heat-treated without being brought into contact with the metal salt. This is called the second stage processing.
The second-stage treatment is performed, for example, by holding the glass after the first-stage treatment at a temperature of 350 ° C. or higher for a certain period of time in the atmosphere. The holding temperature is a temperature equal to or lower than the strain point of the chemically strengthened glass, preferably a temperature 10 ° C. higher than the treatment temperature of the first stage, and more preferably the same temperature as the treatment temperature of the first stage.
According to this treatment, it is considered that the alkaline ions introduced into the glass surface in the first-stage treatment are thermally diffused to lower the CT.

Next, the glass after the second stage treatment is brought into contact with the third metal salt containing potassium (K) ions, and the glass surface is exchanged between K ions in the metal salt and Na ions in the glass. Generates a large compressive stress. This ion exchange treatment may be referred to as a "third stage treatment".
Since the third-stage processing is the same as in the case of the strengthening processing method 1, the description thereof will be omitted.

In the strengthening treatment method 2, the total treatment time of the first to third stages can be set to 24 hours or less, which is preferable because of high productivity. The total processing time is more preferably 15 hours or less, further preferably 10 hours or less.

According to the strengthening treatment method 1, the stress profile can be precisely controlled by adjusting the composition of the second metal salt used in the second-stage treatment and the treatment temperature.
According to the tempered treatment method 2, a chemically strengthened glass having excellent properties can be obtained at low cost by a relatively simple treatment.

As the treatment conditions for the chemical strengthening treatment, the time, temperature, etc. may be appropriately selected in consideration of the characteristics and composition of the glass, the type of molten salt, and the like.
The chemically strengthened glass 2 is manufactured by the above procedure.

Next, the anti-fingerprint treatment layer 81 is formed on the first main surface 21 of the chemically strengthened glass 2.
As a forming method, a vacuum vapor deposition method (dry method) in which a fluorine-containing organic compound or the like is evaporated in a vacuum chamber and adhered to the surface of the antireflection layer, or a fluorine-containing organic compound or the like is dissolved in an organic solvent to form a predetermined method. A method of adjusting the concentration to a concentration and applying it to the surface of the antireflection layer (wet method) or the like can be used.

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

As a method for forming a fluorine-containing organosilicon compound film, a composition of a silane coupling agent having a fluoroalkyl group such as a fluoroalkyl group containing a perfluoroalkyl group; a perfluoro (polyoxyalkylene) chain is spin-coated. Examples include a method of applying by a method, a dip coating method, a casting method, a slit coating method, a spray coating method, etc. and then heat-treating, or a vacuum vapor deposition method in which a fluorine-containing organosilicon compound is vapor-deposited and then heat-treated. Be done.
The formation of the fluorine-containing organosilicon compound film is preferably carried out using a film-containing composition containing a fluorine-containing hydrolyzable silicon compound.
The above is the description of the example of the manufacturing method of the cover glass 1.

[Action and effect of cover glass 1]
Since the amount of triboelectric charge on the surface of the fingerprint prevention treatment layer 81 of the cover glass 1 is 0 kV or less and −1.5 kV or more, it is difficult for the cover glass 1 to be triboelectricly charged even if the user's finger or the like comes into contact with the surface, and the display device When incorporated, it is possible to prevent white turbidity due to static electricity.
Since the cover glass 1 suppresses triboelectric charging due to the physical characteristics of the chemically strengthened glass, it is not necessary to provide a conductive layer, and white turbidity can be prevented without increasing the thickness and man-hours.
The cover glass 1 has a depth DOL of 60 μm or more in the compressive stress layers 25 and 32 of the chemically strengthened glass 2. Therefore, when an impact is applied from the outside, the 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.

Cover glass 1 is chemically tempered glass 2, of the oxide components constituting the tensile stress layer, without contributing to skeletal formation of the glass, Li ₂ O performing neutralization combines with high mobility static, Na ₂ O When _{the total concentration of K 2} O is A mol% and _{the concentration of Al 2} O ₃ is B mol%, A is 14.5 or more and A × B is 120 or more. Alternatively, when the total concentration of _{Li 2} O, Na ₂ O, and K ₂ O among the oxide components constituting the tensile stress layer is _{C mass% and the concentration of Al 2} O ₃ is D mass%, C is 11 or more and C × D is 140 or more.
_{Therefore, since it contains a certain amount or more of Li 2} O, Na ₂ O, and K ₂ O that do not contribute to the formation of the skeleton of the glass and have high mobility and perform static electricity elimination in combination with static electricity, the user's finger or the like comes into contact with the surface. However, it is more difficult to be triboelectrically charged.
Furthermore, contributes to skeletal formation, and Li ₂ O, for containing Na ₂ O, Al ₂ close to the K ₂ O O ₃ also a certain amount or _{more, Li 2 O, Na 2 O} , K 2 O is entered into between the networks Extend the distance with. Therefore, Li ₂ O, Na ₂ O, and K ₂ O are more easily moved, and even if the user's finger or the like comes into contact with the surface, triboelectric charging is less likely to occur.

_{In the chemically strengthened glass 2, the total concentration of SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer is 81 mol% or less (or 82% by mass or less). ), Therefore, the concentrations of _{SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ , which contribute to the formation of the skeleton of glass and have high mobility and weak action to eliminate static electricity in combination with static electricity, are high. It is suppressed below a certain level.
Therefore, even if the user's finger or the like comes into contact with the surface, triboelectric charging is less likely to occur.

[Modification example]
The present invention is not limited to the above-described embodiment, and various improvements and design changes can be made without departing from the gist of the present invention. The specific procedure, structure, and the like for carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

The shape of the chemically strengthened glass 2 may be not only a plate having only a flat surface, but also a plate having a curved surface at least partially or a plate having a concave portion. For example, as shown in FIG. 2, the chemically strengthened glass 2 may be bent glass. By using the bent glass, even if the mating member to which the cover glass 1 is attached has a bent shape, there is no possibility that the accuracy of attachment is lowered.
The thickness of the chemically strengthened glass 2 is preferably 0.5 mm or more. If the glass has a thickness of 0.5 mm or more, there is an advantage that the cover glass 1 having both high strength and good texture can be obtained. The thickness is more preferably 0.7 mm or more. When used in an in-vehicle display device, it is preferably 1.1 mm or more in order to ensure impact resistance that can withstand a head impact test. From the viewpoint of weight reduction and ensuring the transmittance, 5 mm or less is preferable, and 3 mm or less is more preferable.
The planar shape of the chemically strengthened glass 2 is not particularly limited. It does not limit the area in particular of the first major surface 21 and second major surface 22 but, for example 5000 mm ² ～50000Mm ² about.

As shown in FIG. 3, at least one of the first main surface 21 and the second main surface 22 of the chemically strengthened glass 2 is subjected to antiglare treatment (AG treatment) as the functional layer 3. At least one of a glare layer and an antireflection layer subjected to an antireflection treatment (AR treatment) may be provided.
When the anti-glare layer or the anti-reflection layer is provided on the main surface on the side where the anti-fingerprint treatment layer 81 is provided, the anti-glare functional layer or the anti-reflection layer is provided between the chemically strengthened glass 2 and the anti-fingerprint treatment layer 81.
By providing the antiglare layer as the functional layer 3, the light incident from the second main surface 22 side can be scattered and the reflection by the incident light can be blurred.
Examples of the method of imparting antiglare property include a method of forming an uneven shape on the second main surface 22 of the chemically strengthened glass 2. Either the antiglare layer is provided after the chemical strengthening, or the chemical strengthening treatment is performed after the antiglare layer is provided.

As a method for forming the uneven shape, a known method can be applied. A method of chemically or physically surface-treating the second main surface 22 of the chemically strengthened glass 2 to form an etching layer to form an uneven shape having a desired surface roughness, or coating with an antiglare film or the like. A method of pasting layers is available.
When the antiglare layer is an etching layer, it is advantageous in that it is not necessary to separately coat the antiglare material. When the antiglare layer is a coating layer, it is advantageous in that the antiglare property can be easily controlled by selecting the material.

Frost treatment can be mentioned as a method of chemically performing antiglare treatment. The frost treatment can be realized, for example, by immersing a glass substrate as an object to be treated in a mixed solution of hydrogen fluoride and ammonium fluoride. Examples of the method of physically performing the antiglare treatment include sandblasting in which crystalline silicon dioxide powder, silicon carbide powder, etc. are sprayed onto the main surface of the glass substrate with pressurized air, crystalline silicon dioxide powder, silicon carbide powder, etc. A method of rubbing a brush to which the powder is attached with a water-moistened one can be used.

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) is more preferably 0.01 μm to 0.3 μm, and even more preferably 0.02 μm to 0.2 μm. By setting the surface roughness (RMS) in the above range, the haze value of the transparent substrate having the antiglare layer can be adjusted to 1% to 30%. The haze value is a value defined by JIS K 7136 (2000).

By providing the antireflection layer as the functional layer 3, since the antireflection layer is provided on the first main surface 21 side, it is possible to prevent the reflection of the light incident from the first main surface 21 side, and the reflection by the incident light can be prevented. Can prevent crowding. Examples of the antireflection layer include the following.
(1) An antireflection layer having a multi-layer 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 made of a low refractive index layer having a lower refractive index than the chemically strengthened glass 2.

The antireflection layer (1) 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 550 nm and a low refractive index layer having a refractive index of 1.6 or less for light having a wavelength of 550 nm are laminated. It is preferable to provide. 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 more reliably prevented.

The number of layers of the high refractive index layer and the low refractive index layer in the antireflection layer may be a form including one layer each, or may include two or more layers each. In the case of a configuration including one high refractive index layer and one low refractive index layer, it is preferable that the high refractive index layer and the low refractive index layer are laminated in this order on the first main surface 21 of the chemically strengthened glass 2. Further, in the case of a configuration including two or more layers each having a high refractive index layer and a low refractive index layer, a laminated body in which high refractive index layers and low refractive index layers are alternately laminated is preferable. From the viewpoint of productivity, the laminate is preferably two or more and eight or less layers as a whole, and more preferably two or more and six or less layers. Further, the layer may be added within a range that does not impair the optical characteristics. For example, in order to prevent Na diffusion from the glass plate, a SiO ₂ film may be inserted between the glass and the first layer.

The materials constituting the high refractive index layer and the low refractive index layer are not particularly limited, and can be selected in consideration of the required degree of antireflection and productivity. 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 ), and silicon nitride (SiN). And so on. One or more selected from these materials can be preferably used. Materials constituting the low refractive index layer include silicon oxide (particularly silicon dioxide SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), magnesium fluoride (MgF ₂ ), and 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 can be preferably used.

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

The antireflection layer can be obtained by a method of directly forming an inorganic thin film on the surface, a method of surface treatment by a method such as etching, or a dry method, for example, a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, particularly a physical vapor deposition method. It can be suitably formed by a kind of vacuum deposition method or sputter method.

The thickness of the antireflection layer is preferably 90 nm to 500 nm. It is preferable that the thickness of the antireflection layer is 90 nm or more because the reflection of external light can be effectively suppressed.

In the CIE (International Commission on Illumination) color difference formula, the antireflection layer preferably has a reflection color of a ^* of 6-1 and b ^* of -8 to 1 of the cover glass with a film.
When a ^{* of the} antireflection layer is -6 to 1 and b ^* is -8 to 1, there is no risk that the antireflection layer will be colored as a dangerous color (warning color), and the color of the antireflection layer will be conspicuous. Can be prevented.
When the antireflection layer and the antifingerprint treatment layer 81 are formed directly on the glass without forming the antiglare layer, the cover glass 1 reflects after removing the antifingerprint treatment layer 81 by corona treatment or plasma treatment. The surface roughness measured on the surface of the prevention treatment layer is preferably less than 1 nm in Ra. If the contact angle of water on the surface is about 20 ° or less, it can be determined that the antifouling film has been removed. When the surface roughness Ra after removing the outermost surface anti-fingerprint treatment layer 81 is less than 1 nm, high scratch resistance can be realized. It is more preferably 0.3 nm to 0.6 nm, and particularly preferably 0.3 nm to 0.5 nm.
The surface roughness Ra can be measured, for example, in the DFM mode of the scanning probe microscope SPI3800N manufactured by Seiko Instruments Inc.

As shown in FIG. 4, the cover glass 1 may include 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, a layer having a visible transmittance of light having a wavelength of 380 nm to 780 nm of 50% or less. By providing the light-shielding layer 31, it is possible to conceal the wiring on the display device side or conceal the illumination light of the backlight to prevent the illumination light from leaking from the periphery of the display device.
The first main surface 21 and the chamfered portion 24 on which the light-shielding layer 31 is provided may be subjected to a primer treatment, an etching treatment, or the like in order to improve the adhesion with the light-shielding layer 31.

The method of providing the light-shielding layer 31 is not particularly limited, and examples thereof include a method of providing the light-shielding layer 31 by printing ink by a barcode method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, a screen method, an inkjet method, or the like. The screen method is preferable in consideration of the easy difference in thickness control.
The ink used for the light-shielding layer 31 may be inorganic or organic. Examples of the inorganic ink include one or more selected from _{SiO 2} , ZnO, B ₂ O ₃ , Bi ₂ O ₃ , Li ₂ O, Na ₂ O and K _{2 O, CuO, Al 2} O ₃ , and the like. The composition may consist of one or more selected from _{ZrO 2} , SnO ₂ and CeO _{2 , Fe 2} O ₃ and TiO _2.

As the organic ink, various printing materials in which a resin is dissolved in a solvent can be used. For example, as the resin, acrylic resin, urethane resin, epoxy resin, polyester resin, polyamide resin, vinyl acetate resin, phenol resin, olefin, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, natural rubber, styrene-butadiene co-weight. At least one selected from the group consisting of resins such as coalescing, acrylic nitrile-butadiene copolymer, polyester polyol, and polyether polyurethane polyol may be selected and used. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents may be used. For example, isopropyl alcohol, methanol, ethanol and the like can be used as the alcohols, ethyl acetate can be used as the esters, and methyl ethyl ketone can be used as the ketones. Toluene, xylene, Solbesso (registered trademark) 100, Solbesso (registered trademark) 150 and the like can be used as the aromatic hydrocarbon solvent, and hexane and the like can be used as the aliphatic hydrocarbon solvent. These are given as examples, and various other printing materials can be used. The organic printing material can be applied to the chemically strengthened glass 2 and then the solvent is evaporated to form the light-shielding layer 31 of the resin. It may be a thermosetting ink that can be cured by heating, or a UV curable ink, and there is no particular limitation.

The ink used for the light-shielding layer 31 may contain a colorant. As the colorant, for example, when the light-shielding layer 31 is black, a black colorant such as carbon black can be used. In addition, a colorant of an appropriate color can be used according to the desired color.
The light-shielding layer 31 may be laminated as many times as desired, and the ink used for printing may be different for each layer. Further, the light-shielding layer 31 may be printed not only on one main surface but also on the other main surface, and may be printed on the end surface.
When the light-shielding layers 31 are laminated a desired number of times, different inks may be used for each layer. For example, if the user wants the light-shielding layer 31 to appear white when the cover glass 1 is viewed from the first main surface 21 side, the first layer is printed in white, and then the second layer is printed in black. Just print it. As a result, when the user sees the light-shielding layer 31 from the first main surface 21 side, the white light-shielding layer 31 that suppresses the so-called "transparency" related to the visibility of the back surface of the light-shielding layer 31 can be formed.

The planar shape of the light-shielding layer 31 is a frame shape in FIG. 4, and the inside of the frame constitutes the display area 4, but it is not a frame shape but a linear shape along one side of the second main surface 22 and two continuous sides. It may be an L-shape along the line, or two straight lines along the two opposite sides. When the second main surface 22 is a polygon other than a quadrangle, a circle, or a variant, the light-shielding layer 31 has a frame shape corresponding to these shapes, a straight line along one side of the polygon, and an arc shape along a part of the circle. But it may be.
When the cover glass 1 is used as a display device, the light-shielding layer 31 preferably has a color corresponding to the color when the display device is not displayed. For example, when the color when not displayed is black, it is desirable that the light-shielding layer 31 is also black.

When the cover glass 1 includes the light-shielding layer 31, the light-shielding layer 31 may have an opening 33 as shown in FIG. 5, and the opening 33 has an infrared-transmitting layer having a higher infrared transmittance than the light-shielding layer 31. It is preferable to include 35. By providing the opening 33 in a part of the light-shielding layer 31 and providing the infrared-transmitting layer 35, the infrared sensor can be provided on the back side of the light-shielding layer 31, and the infrared-transmitting layer 35 can be made inconspicuous.
The ink forming the infrared transmissive layer 35 may be inorganic or organic. Examples of the pigment contained in the inorganic ink include one or more selected from _{SiO 2} , ZnO, B ₂ O ₃ , Bi ₂ O ₃ , Li ₂ O, Na ₂ O and K _{2 O, CuO, Al 2} The composition may consist of one or more selected from _{O 3} , ZrO ₂ , SnO ₂ and CeO _{2 , Fe 2} O ₃ and TiO _2.

As the organic ink, various printing materials in which a resin and a pigment are dissolved in a solvent can be used. For example, as the resin, acrylic resin, urethane resin, epoxy resin, polyester resin, polyamide resin, vinyl acetate resin, phenol resin, olefin, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, natural rubber, styrene-butadiene co-weight. At least one selected from the group consisting of resins such as coalescing, acrylic nitrile-butadiene copolymer, polyester polyol, and polyether polyurethane polyol may be selected and used. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents may be used. For example, isopropyl alcohol, methanol, ethanol and the like can be used as the alcohols, ethyl acetate can be used as the esters, and methyl ethyl ketone can be used as the ketones. Toluene, xylene, Solbesso (registered trademark) 100, Solbesso (registered trademark) 150 and the like can be used as the aromatic hydrocarbon solvent, and hexane and the like can be used as the aliphatic hydrocarbon solvent. These are given as examples, and various other printing materials can be used. The organic printing material can be applied to the chemically strengthened glass 2 and then the solvent is evaporated to form the infrared transmissive layer 35 of the resin. It may be a thermosetting ink that can be cured by heating, or a UV curable ink, and there is no particular limitation.

The ink used for the infrared transmissive layer 35 may contain a pigment. As the pigment, for example, when the infrared transmissive layer 35 is black, a black pigment such as carbon black can be used. In addition, a pigment having an appropriate color can be used according to the desired color.

The content ratio of the pigment in the infrared transmissive layer 35 can be freely changed according to the desired optical characteristics. The content ratio, which is the ratio of the content of the pigment to the total mass of the infrared transmissive layer 35, is preferably 0.01% by mass to 10% by mass. The content ratio can be realized by adjusting the content ratio of the infrared transmissive material with respect to the total mass of the ink.

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

The method for forming the infrared transmissive layer 35 is not particularly limited, and examples thereof include a barcode method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, a screen method, and an inkjet method. Considering the continuity of the production method, the same forming method as that of the light-shielding layer 31 is preferable.

The cover glass 1 of the present invention can be used, for example, as a cover member for a panel display such as a liquid crystal display, a cover member for a display device such as a cover glass for an in-vehicle information device or a portable device. By using the cover glass 1 of the present invention as a cover for a display device, it is possible to protect an object and prevent white turbidity when using a touch sensor.
Further, the cover glass 1 of the present invention is applied to the surface of the cover glass when, for example, a panel display such as a liquid crystal display or an organic EL display, an in-vehicle information device, or a portable device is manufactured, or when the panel and the cover glass are bonded to each other. Since the charge on the cover glass generated when the laminate to be attached is peeled off is suppressed, it is possible to suppress the adsorption of foreign substances due to the charge.

Here, an example of a display device including the cover glass 1 will be described with reference to FIG. Here, an in-cell type IPS (In Plane Switching) liquid crystal display device will be illustrated.
The display device 10 shown in FIG. 6 includes a frame 5. The frame 5 includes a bottom portion 51, a side wall portion 52 that intersects the bottom portion 51, and an opening 53 that faces the bottom portion 51. The liquid crystal module 6 is arranged in the space surrounded by the bottom portion 51 and the side wall portion 52. The liquid crystal module 6 includes a backlight 61 arranged on the bottom 51 side and a liquid crystal panel 62 (display panel) arranged on the backlight 61. The liquid crystal panel 62 is an in-cell type that includes an IPS liquid crystal and has an element having a touch function embedded in the liquid crystal element.
A cover glass 1 is provided at the upper end of the frame 5 so that the second main surface 22 faces the liquid crystal module 6 side. The cover glass 1 is attached 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 portion 52.

It is preferable that the adhesive layer 7 is transparent and has a small difference in refractive index from the chemically strengthened glass 2.
Examples of the adhesive layer 7 include a layer made of 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. Among them, a photocurable resin composition containing a curable compound and a photopolymerization initiator is preferable. The curable resin composition is applied by a method such as a die coater or a roll coater 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 attached 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, and more preferably 50 μm or more and 200 μm or less. The storage shear elastic modulus of the adhesive layer 7 is preferably 5 kPa or more and 5 MPa or less, and more preferably 1 MPa or more and 5 MPa or less.

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

Next, examples of the present invention will be described. The present invention is not limited to the following examples.
Cover glasses having various characteristics were prepared, and the amount of charge and the degree of white turbidity when incorporated into the apparatus were determined. The specific procedure is as follows. Example 1 is an example, and Examples 2 to 6 are comparative examples.

(Example 1)
First, as the glass before chemical strengthening, the raw materials are mixed and melted so as to obtain the glass having the composition shown in Example 1 in Table 1, and the glass is poured out to form a block of about 110 mm square, and then slowly cooled. I went and got a glass body. Then, it was cut and cut so as to form a plate having a length of 100 mm, a width of 100 mm, and a thickness of 0.7 mm.
The glass was then chemically strengthened. The conditions for chemical strengthening were as follows: immersion in a 100 wt% sodium nitrate solution at a temperature of 450 ° C. for 3 hours, and then immersing in a 100 wt% potassium nitrate solution at a temperature of 450 ° C. for 3 hours for chemical enhancement.
After cleaning the strengthened glass, a solution obtained by diluting Afluid S-550 manufactured by Asahi Glass Co., Ltd. with Asahi Clean AC6000, a fluorine solvent manufactured by Asahi Glass Co., Ltd. to 0.1 wt% as an anti-fingerprint treatment layer 81 on the surface is formed by a spray coating method. And used as a cover glass. The film thickness was 5 nm.
The total composition (mol%, mass%) of each glass of Examples 1 to 6 in Table 1 may not be 100, but it is the result of rounding off each value and is described in the claim. It has no particular effect on the calculation of concentration.
The following evaluation was performed on the produced cover glass.
<CS, DOL>
Using the glass surface stress meter (FSM-6000LE) manufactured by Orihara Seisakusho and the measuring machine SLP1000 manufactured by Orihara Seisakusho, which applies scattered photoelasticity, the stress distribution in the thickness direction of the glass is measured, and the stress distribution on the outermost surface is measured. The stress value was defined as the surface compressive stress CS. The glass depth at which the stress value becomes 0 MPa inside the glass was defined as the compressive stress depth DOL.
<CT>
It was approximately calculated by the relational expression CT = (CS × DOL) / (t-2 × DOL).
<Triboelectric charge>
The triboelectric charge amount was determined by the D method (triboelectric attenuation measurement method) described in JIS L1094: 2014 using a friction band voltage attenuation measuring device manufactured by INTEC Inc.
<Whitening>
The obtained cover glass is incorporated into an in-cell type IPS liquid crystal display device, and with the power turned on, the surface of the cover glass is touched with a finger, and the finger touches the surface of the cover glass at a speed of 1 reciprocation per second for 10 reciprocations. It moved and visually confirmed the presence or absence of clouding. Those that became cloudy were judged to be "yes", and those that did not become cloudy were judged to be "absent".

(Example 2)
As the glass before chemical strengthening, the glass having the composition shown in Example 2 in Table 1 was produced by the float method to obtain a 0.7 mm glass plate, and the glass was immersed in a 100 wt% potassium nitrate solution at 420 ° C. for 8 hours. The cover glass was manufactured under the same conditions as in Example 1 except that the cover glass was chemically strengthened.

(Example 3)
Example 1 except that the glass having the composition shown in Example 3 in Table 1 was used as the glass before chemical strengthening, and the glass was chemically strengthened by immersing it in a 100 wt% potassium nitrate solution at 425 ° C. for 6 hours. The cover glass was manufactured under the same conditions as above.

(Example 4)
As the glass before chemical strengthening, the glass having the composition shown in Example 4 in Table 1 was used, and the glass was chemically strengthened by immersing it in a 100 wt% potassium nitrate solution at a temperature of 425 ° C. for 6 hours. The cover glass was manufactured under the same conditions.

(Example 5)
As the glass before chemical strengthening, the raw materials were mixed and melted so as to obtain the glass having the composition shown in Example 5 in Table 1 to obtain a glass block, and the glass was prepared in a 100 wt% sodium nitrate solution at a temperature of 450 ° C. A cover glass was produced under the same conditions as in Example 1 except that the glass was immersed for 2 hours and then chemically strengthened by being immersed in a 100 wt% potassium nitrate solution at a temperature of 425 ° C. for 1.5 hours.

(Example 6)
As the chemically strengthened glass, a cover glass was produced under the same conditions as in Example 1 except that the glass having the composition shown in Example 6 in Table 1 was used.
The above results are shown in Table 1.

As shown in Table 1, in Example 1, the triboelectric charge amount is 0 kV or less, -1.5 kV or more, the depth DOL of the compressive stress layer is 60 μm or more, and among all the alkali metals contained in the tensile stress layer. , The number of moles of Li was the largest, and white turbidity did not occur.
In Examples 2 to 4, since the DOL was less than 60 μm, the impact resistance of the glass surface was inferior, and it was not suitable as a cover glass.
In Examples 4 to 6, the triboelectric charge amount was less than −1.5 kV, and white turbidity occurred.
In Example 1, CS was about 800 to 1000 MPa and CT was about 60 MPa.
In Example 1, A was 14.5 mol or more and A × B was 120 or more.
In Example 1, _{the total concentration of SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ was 81 mol% or less.

From the above results, the triboelectric charge amount is 0 kV or less, -1.5 kV or more, the depth DOL of the compressive stress layer is 60 μm or more, and the number of moles of Li among all the alkali metals contained in the tensile stress layer is It was found that by using the largest composition, a cover glass that can prevent white turbidity and has excellent impact resistance can be obtained.

1 ... Cover glass, 2 ... Chemically tempered glass, 3 ... Functional layer, 4 ... Display area, 5 ... Frame, 6 ... Liquid crystal module, 7 ... Adhesive layer, 10 ... Display device, 21 ... First main surface, 22 ... Second main surface, 23 ... end face, 24 ... chamfered portion, 25 ... compressive stress layer, 27 ... tensile stress layer, 31 ... light-shielding layer, 32 ... compressive stress layer, 33 ... opening, 35 ... infrared transmissive layer, 51 ... bottom, 52 ... side wall, 53 ... opening, 61 ... backlight, 62 ... liquid crystal panel, 81 ... anti-fingerprint layer

Claims (11)

Chemically tempered glass with a first and second main surface,
An anti-fingerprint treatment layer provided on the first main surface of the chemically strengthened glass,
With
The chemically strengthened glass is
Among all alkali metals contained in the tensile stress layer, the number of moles of Li is the largest,
The depth DOL of the compressive stress layer is 60 μm or more,
A cover glass characterized in that the amount of triboelectric charge on the surface of the anti-fingerprint treatment layer is 0 kV or less and −1.5 kV or more by the D method described in JIS L1094: 2014. The chemically strengthened glass is
_{When the total concentration of Li 2} O, Na ₂ O, and K ₂ O among the oxide components constituting the tensile stress layer is A mol%, and the concentration of Al ₂ O ₃ is B mol%, A is 14. The cover glass according to claim 1, wherein the cover glass is 5 or more and A × B is 120 or more. The chemically strengthened glass is
Of the oxide components constituting the tensile stress layer, when _{the total concentration of Li 2} O, Na ₂ O, and K ₂ O is C mass% and _{the concentration of Al 2} O ₃ is D mass%, C is 11 or more. The cover glass according to claim 1, wherein C × D is 140 or more. The chemically strengthened glass is
The cover according to claim 1 or 2, wherein the total concentration of _{SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer is 81 mol% or less. Glass. The chemically strengthened glass is
The cover according to claim 1 or 2, wherein the total concentration of _{SiO 2} , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ among the oxide components constituting the tensile stress layer is 82% by mass or less. Glass. The cover glass according to any one of claims 1 to 5, further comprising at least one of an antiglare function layer and an antireflection layer provided between the chemically strengthened glass and the anti-fingerprint treatment layer. The cover glass according to any one of claims 1 to 6, further comprising a light-shielding layer provided on the second main surface.
Shading layer The light-shielding layer has an opening and
The cover glass according to claim 7, wherein an infrared transmitting layer having an infrared transmittance higher than that of the light shielding layer is provided at the opening. The cover glass according to any one of claims 1 to 8, wherein the chemically strengthened glass is bent glass. The cover glass according to any one of claims 1 to 9, wherein the surface roughness measured on the surface of the anti-fingerprint treatment layer when having an antiglare layer is 0.01 μm to 0.5 μm in Ra. An in-cell type IPS liquid crystal display device including the cover glass according to any one of claims 1 to 10.

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