JP2001290005A - cover glass - Google Patents

Abstract

(57) [Problem] To provide a cover glass that can reduce the reflection of external light, improve the light transmittance, and improve the visibility of a display device in a portable device. SOLUTION: An anti-reflection film (4, 5) is provided on at least the outer surface side of a cover glass substrate (2), preferably on both the outer surface side and the inner surface side. Further, the hard coat film 3 is interposed between the cover glass substrate 2 and the antireflection film 4. An anti-reflection film 7 is used as an anti-reflection film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover glass fixed to a window of a housing of a portable device and used for seeing through the inside of the housing.

[0002]

2. Description of the Related Art In a portable device having a liquid crystal display device such as a cellular phone, the display surface of the liquid crystal display device is made of a thin inorganic glass, so that the liquid crystal display device is exposed on the outer surface of the portable device. The liquid crystal may be broken by an external force or impact during use. For this reason, the liquid crystal display device is housed in a slightly recessed position inside the housing, a window is provided in the housing so that the display surface can be viewed, and a transparent cover glass is fixed so as to close this window. A configuration for protecting the display surface of the display device is employed.

[0003] The cover glass is made of an injection molded article of a transparent resin such as an acrylic resin or a polycarbonate resin which is lightweight, has a low processing cost, and is excellent in impact resistance, and is generally used to prevent scratches on the outer surface. Is applied.

[0004] In order to cover and protect the display surface of the liquid crystal display device with such a cover glass, the display surface of the liquid crystal display device is visible through the cover glass. Therefore, the optical performance of the cover glass has a great effect on the visibility of the display surface.

[0005]

However, the conventional cover glass has poor optical performance, so that the display visibility of the liquid crystal display device is not sufficient.

That is, since the power supply of a portable device is a battery,
In order to prolong the battery life, liquid crystal display devices are mainly of a reflection type using reflection of external light from the surface side, and are turned off in a short time even with a built-in backlight.

[0007] Therefore, in portable equipment used in various environments such as indoor, outdoor, day and night, the external light and the illumination change, and the external light is reflected on the surface of the cover glass, causing the display to flicker or the illumination to change. There is a problem that the image is reflected on the cover glass and the display is difficult to see.

Further, when the cover glass is interposed, there is a problem that the light transmittance is reduced and the reading of the display of the reflection type liquid crystal display device is adversely affected. In particular, in the case of a recent color liquid crystal display device, the amount of display light is further reduced by absorption of a color filter, and therefore, there is a problem that a reduction in light transmittance due to a cover glass is greatly affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a cover glass capable of reducing the reflection of external light, improving the light transmittance, and improving the visibility of a display device in a portable device. The purpose is to provide.

[0010]

In order to achieve the above object, the present invention provides an antireflection film on at least the outer surface side of a transparent cover glass substrate, preferably on both the outer surface side and the inner surface side. The present invention has succeeded in remarkably suppressing the reflection of external light on the cover glass, improving the light transmittance, and dramatically improving the visibility of the display device in the portable device.

That is, by providing an antireflection film on the outer surface side of the cover glass, reflection on the outer surface of the cover glass can be suppressed, and the visibility of the display device can be improved.

Further, when the display device is protected by the cover glass, there is a gap (air layer) between the cover glass and the display surface of the display device. Therefore, light incident on the cover glass from the outside passes through the cover glass, reaches the display device, is reflected by the display device, passes through the cover glass again, and enters the eye. At this time, a part of the light is reflected on the surface of the cover glass, and a part of the light reflected from the display device is reflected on the surface of the cover glass. The rate is decreasing.

Therefore, by providing an antireflection film not only on the outer surface side but also on the inner surface side of the cover glass, the light transmittance of the cover glass can be greatly improved, and the visibility of the display device can be improved. it can.

By using an inexpensive anti-reflection film as the anti-reflection film, the cost of providing the anti-reflection film can be reduced, and the production cost of the cover glass can be reduced.

Further, an antireflection film formed by vapor deposition generally has poor adhesion to a cover glass substrate.
By interposing a hard coat film between the cover glass substrate and the anti-reflection film, it is possible to prevent the cover glass from being damaged and to improve the adhesion of the anti-reflection film.

When an antireflection film is provided on both the outer surface and the inner surface of the cover glass, the antireflection film on the inner surface does not need to have strong adhesion to the cover glass substrate. It is preferable that a hard coat film is interposed only in the film.

Since the anti-reflection film is relatively hard and difficult to stick on a curved surface, an anti-reflection film formed by vapor deposition is provided on the outer surface side of the cover glass which is often formed into a curved surface, and is formed in a planar shape. It is preferable to stick an antireflection film on the inner surface side of the cover glass to be formed.

It is advantageous in terms of cost to provide the hard coat film by hot stamping.

In order to improve the adhesion to the antireflection film, it is preferable to use a hard coat film obtained by applying and curing a coating composition containing metal oxide fine particles.

The provision of the decorative portion on the antireflection film simplifies the manufacturing process as compared with the case where a decorative portion is separately formed, and is advantageous in terms of cost.

When a hard coat film is provided, the impact resistance of the cover glass can be improved by interposing a primer layer between the hard coat film and the cover glass substrate.

Further, in a portable device, the cover glass is easily stained by touching the cover glass with a hand, but the dirt can be easily wiped off by applying a water and oil repellent treatment, and the anti-reflection film Can be improved in durability.

Therefore, the invention according to claim 1 is a cover glass fixed to a window of a housing of a portable device and used for seeing through the inside of the housing, wherein an outer surface side of a transparent cover glass substrate is provided. Or an antireflection film provided on both the outer surface side and the inner surface side.

According to a second aspect of the present invention, in the cover glass of the first aspect, the anti-reflection film is provided on the cover glass substrate via a base film of the anti-reflection film. To provide a cover glass.

According to a third aspect of the present invention, in the cover glass according to the first or second aspect, a hard coat film is interposed between the cover glass substrate and the antireflection film. Provide glass.

According to a fourth aspect of the present invention, in the cover glass according to the third aspect, the anti-reflection film is provided on an outer surface side of the cover glass substrate with the hard coat film interposed therebetween. Provided is a cover glass, wherein the antireflection film is provided on the inner surface side without interposing the hard coat film.

According to a fifth aspect of the present invention, in the cover glass according to the fourth aspect, the anti-reflection film on the inner surface side of the cover glass substrate is attached to the cover glass substrate via a base film of the anti-reflection film. Provided is a cover glass, which is provided.

According to a sixth aspect of the present invention, there is provided the cover glass according to the third aspect, wherein the hard coat film is provided by hot stamping.

According to a seventh aspect of the present invention, in the cover glass according to the third aspect, the hard coat film has the following components (A) and (B), (A) having a particle diameter of 1 to 100 millimicrons. , Sn, Sb, Ce, Zr, and at least one metal oxide fine particle selected from Ti and / or Si, A
1, Sn, Sb, Ta, Ce, La, Fe, Zn, W,
Composite fine particles composed of two or more metal oxides selected from Zr, In, and Ti, and (B) coating and curing a coating composition mainly containing a silane compound having a polymerizable group and a hydrolyzable group. A cover glass is provided.

According to an eighth aspect of the present invention, there is provided a cover glass according to the second aspect, wherein a decorative portion is provided on the antireflection film.

According to a ninth aspect of the present invention, there is provided a cover glass according to the third aspect, wherein a primer layer is interposed between the cover glass substrate and the hard coat film. I do.

According to a tenth aspect of the present invention, in the cover glass according to any one of the first to ninth aspects, the surface of the antireflection film provided on the outer surface side of the cover glass substrate is subjected to a water / oil repellent treatment. Provided is a cover glass characterized by being provided with a cover glass.

The eleventh aspect of the present invention relates to the first to tenth aspects.
The cover glass according to any one of the claims, wherein the cover glass is used to cover and protect a display surface of a liquid crystal display device housed in a housing of the portable device, and to be used for visually recognizing the display surface. I do.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the cover glass of the present invention will be described, but the present invention is not limited to the following embodiments.

The cover glass of the present invention is used for the purpose of being fixed to the window of the housing of the portable device and seeing through the inside of the housing, and does not directly hit the display surface of the display device of the portable device. As described above, a typical use is to cover the display surface of a liquid crystal display device housed inside a housing to protect the display surface and to visually recognize the display surface. As other uses, it can also be used for applications such as viewing windows inside portable devices.

The cover glass of the present invention can be used, for example, for mobile phones, portable game machines, digital cameras, portable wireless communication devices,
It can be used to protect the display surface of a display device such as a portable radio, a wristwatch, and a portable audio device. As the display device, a liquid crystal display device is typical, and it is particularly effective for a color reflection type liquid crystal display device using external light.

FIG. 1 shows an example of a cover glass 1 used for protecting a liquid crystal display device 30 housed inside a housing 20 of a mobile phone 100. A decorative portion 11 that does not transmit light by plating, printing, or the like is often formed on the peripheral portion of the cover glass 1.

FIG. 2 is a cross-sectional view of the periphery of the cover glass 1 taken along line AA ′ of FIG.
An example of a structure in which the liquid crystal display device 30 of FIG. As shown in FIG. 2, the housing 20 corresponding to the display surface 31 of the liquid crystal display device 30 which is disposed slightly inside the housing 20 of the portable device has a window 21 through which the display surface 31 can be visually recognized from the outside. It is open. Cover glass 1
Is fixed to a frame portion 22 protruding from the window portion 21 and closes the window portion 21. The inner surface of the cover glass 1 is arranged so as to form a gap 23 with the display surface 31 so that the cover glass 1 does not directly hit the display surface 31 of the liquid crystal display device 30 even if the cover glass 1 is deformed inward by an external force. Have been.

External light L incident on the cover glass 1 from outside
1 is transmitted through the cover glass 1 and reaches the liquid crystal display device 30, reflected by the liquid crystal display device 30, again transmitted through the cover glass 1 and becomes reflected light L <b> 2 to reach the eyes, and the display of the liquid crystal display device 30 is performed. The surface 31 can be visually recognized. At this time, a part of the external light L1 is reflected by the outer surface 12 of the cover glass 1, and the light reflected by the liquid crystal display device 30 is partially reflected by the inner surface 13 of the cover glass 1.

As described above, since the gap (air layer) 23 exists between the cover glass 1 and the liquid crystal display device 30,
Before the external light L1 is reflected from the liquid crystal display device 30,
This means that the light passes through the cover glass 1 twice and is reflected twice. Therefore, the optical performance of the cover glass 1 greatly affects the visibility of the liquid crystal display device 30.

The shape of the cover glass 1 is the same as that of the outer surface 1.
2 from the appearance requirement to unify the design with the housing 20,
Often, it has a curved shape that matches the outer surface of the housing 20. On the other hand, the inner surface 13 of the cover glass 1
, It is composed of a flat or slightly curved surface.

FIG. 3 shows a sectional structure of a first embodiment of the cover glass of the present invention. In the cover glass 1, a hard coat film 3 is provided on the outer surface side of a cover glass substrate 2 formed in the shape of a cover glass, and an anti-reflection film 4 on the outer surface side is provided on the hard coat film 3. ing. On the other hand, an antireflection film 5 is directly provided on the inner surface side of the cover glass substrate 2.

As the cover glass substrate 2, a transparent resin or inorganic glass which is lightweight, has excellent impact resistance and is thermoplastic is selected. As the transparent resin, for example, a poly (methyl) methacrylate resin, a polycarbonate resin, a polyolefin resin such as polyethylene and polypropylene, or the like is used. The method of forming the cover glass substrate 2 is generally injection molding, but it may be cut from a thin plate into a cover glass shape.

In order to protect the display surface 31 and the cover glass substrate 2 itself from ultraviolet rays, the cover glass substrate 2 is mixed with an ultraviolet absorber in a raw material resin or dissolved in water or an organic solvent. The ultraviolet absorber can be absorbed on the surface of the cover glass substrate 2.

As the ultraviolet absorber, there are cyanoacrylate, salicylic acid, benzophenone, benzotriazole and the like. Examples of the cyanoacrylate-based ultraviolet absorber include ethyl-2-cyano-3,3-diphenylacrylate. Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate and 4-te
Examples thereof include rt-butylphenyl salicylate and p-octylphenyl salicylate. As the benzophenone-based ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,
2-hydroxy-4-octoxybenzophenone, 2,
2'-dihydroxy-4-methoxybenzophenone,
2,2'-dihydroxy-4,4'-dimethoxybenzophenone and the like can be exemplified. Examples of the benzotriazole-based ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2- Hydroxy-
3,5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert)
-Amylphenyl) benzotriazole, 5-chloro-
2- (3,5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3-t
tert-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H-benzotriazole, 2-
(3,5-di-tert-pentyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3,5-
Di-tert-butyl-2-hydroxyphenyl) -2
H-benzotriazole, 2- (2-hydroxy-5-
tert-octylphenyl) -2H-benzotriazole and the like.

Among these ultraviolet absorbers, the benzotriazole-based compounds have good solubility in the raw material monomers, have a high ultraviolet absorption capacity, and the color of the compound alone is pale or white and the cover glass is hardly colored. It is preferable because it has the feature of:

When the ultraviolet absorber is incorporated into the resin, the amount is 0.5 to 5 parts by weight per 100 parts by weight of the raw material monomer.
Parts by weight, preferably 1 to 3 parts by weight. If the blending amount of the ultraviolet absorber is too large, it may be difficult to dissolve the monomer in the raw material, and the ultraviolet absorber may precipitate on the resin surface during molding.

The hard coat film 3 is formed of the cover glass substrate 2
In addition to imparting abrasion resistance to the cover glass substrate 2 and generally having poor adhesion of the antireflection film 4 to the cover glass substrate 2, the antireflection film 4 is interposed between the cover glass substrate 2 and the antireflection film 4. Has the function of improving adhesion and preventing peeling. Since the inner anti-reflection film 5 does not require much adhesion, a hard coat film is not provided in the present embodiment, but, of course, a hard coat film is formed between the anti-reflection film 5 and the cover glass substrate 2. It may be interposed. In addition,
Depending on the type of the cover glass substrate 2 and the type of the anti-reflection film 4, the anti-reflection film 4 may have good adhesion to the cover glass substrate 2, for example, when the cover glass substrate 2 is made of inorganic glass, the hard coat film 3 May be omitted.

The method for forming the hard coat film 3 is generally a method in which a curable composition capable of forming a hard coat film is applied to the surface of the cover glass substrate 2 and the coating film is cured. When the cover glass substrate 2 is made of a thermoplastic resin, a material that is cured by ionizing radiation such as an electromagnetic wave such as ultraviolet rays or an electron beam is preferably used rather than a thermosetting resin. For example, a photo-curable silicone composition containing, as main components, a silicone compound that generates a silanol group upon irradiation with ultraviolet light and an organopolysiloxane having a reactive group such as a halogen atom or an amino group that undergoes a condensation reaction with the silanol group, Mitsubishi Rayon ( Acrylic UV-curable monomer compositions such as UK-6074 manufactured by K.K. In addition, a thermosetting type curable composition can also be used, and a polymerizable group such as a vinyl group, an allyl group, an acrylic group, or a methacryl group and a hydrolyzable group such as an alkoxy group in one molecule. A thermosetting composition containing a silane compound or a silane coupling agent as a main component can be exemplified.

Examples of the silane compound constituting the thermosetting composition include vinyltrialkoxysilane, vinyltrichlorosilane, vinyltri (β-methoxy-ethoxy) silane, allyltrialkoxysilane, acryloxypropyltrialkoxysilane, and methacryl. Oxypropyl trialkoxysilane, methacryloxypropyl dialkoxymethylsilane, γ-glycidoxypropyl trialkoxysilane, β- (3,4-epoxycyclohexyl) -ethyl trialkoxysilane, mercaptopropyl trialkoxysilane, γ-aminopropyl Trialkoxysilane, N-β (aminoethyl)-
γ-aminopropylmethyldialkoxysilane and the like can be exemplified. This silane compound may be used as a mixture of two or more kinds. It is also useful to add a disilane compound represented by the following general formula.

[0051]

Embedded image (Wherein, R ¹ and R ² are a hydrocarbon group having 1 to 6 carbon atoms).
X ¹ and X ² are hydrolyzable groups. Y is an organic group containing a carbonate group or an epoxy group;
Or 1. These disilane compounds can be synthesized by various conventionally known methods. For example, it can be obtained by performing an addition reaction between diallyl carbonate and trichlorosilane or the like, followed by alkoxylation. Alternatively, the compound can be obtained by adding a trichlorosilane or the like to a compound having an addable substituent at both ends and further containing an epoxy group or an epoxidizable functional group therein, followed by alkoxylation. It is more effective to use either of these disilane compounds after hydrolysis or to perform an acid treatment on the cured film.

Further, for the purpose of enhancing the adhesion to the antireflection film 4 composed of an inorganic film, and further for adjusting the refractive index,
To form a hard coat film 3 having a refractive index matching the refractive index of the cover glass substrate 2 and the antireflection film 4 to prevent the occurrence of buffer stripes and improve the appearance, It is preferable to mix it with the curable composition.

The inorganic fine particles may have a particle size of 1 to 100 μm.
Selected from Si, Sn, Sb, Ce, Zr, and Ti
Fine particles comprising at least one kind of metal oxide and / or Si, A
1, Sn, Sb, Ta, Ce, La, Fe, Zn, W,
Composite fine particles composed of two or more metal oxides selected from Zr, In, and Ti can be exemplified.

As a specific example of the inorganic fine particles, Si
O ₂ , SnO ₂ , Sb ₂ O ₅ , CeO ₂ , ZrO ₂ , TiO ₂
Are colloidally dispersed in a dispersion medium such as water, alcohol, or other organic solvents.
Or Si, A1, Sn, Sb, Ta, Ce, La,
Composite fine particles composed of two or more types of inorganic oxides of Fe, Zn, W, Zr, In, and Ti are colloidally dispersed in water, an alcohol, or another organic solvent.

In this case, in order to enhance the dispersion stability of the inorganic fine particles in the curable composition, those obtained by treating the surfaces of these fine particles with an organosilicon compound or an amine compound can be used.

The organosilicon compound used at this time includes monofunctional silane, difunctional silane, trifunctional silane, tetrafunctional silane and the like. In the treatment, the hydrolyzable group may be untreated or hydrolyzed. After the treatment, the hydrolyzable group is-
A state in which it has reacted with an OH group is preferable, but there is no problem in stability even in a state where a part remains.

Examples of the amine compound include ammonium or alkylamines such as ethylamine, triethylamine, isopropylamine and n-propylamine, aralkylamines such as benzylamine, alicyclic amines such as piperidine, monoethanolamine, triethanolamine and the like. Alkanolamines.

It is preferable to add the organic silicon compound and the amine compound in an amount of about 1 to 15% based on the weight of the inorganic fine particles.

The ratio of the inorganic fine particles to the solid content in the coating composition is preferably 0 to 65% by weight, particularly preferably 55% by weight or less. If it exceeds 65% by weight,
The hard coat film may become cloudy and the appearance may deteriorate.

As a method for preparing the thermosetting composition, for example, inorganic fine particles dispersed in a solvent such as an alcohol and an organic solvent such as an alcohol and a silane compound having a polymerizable group and a hydrolyzable group are added, and hydrolyzed with hydrochloric acid or the like. Is adopted.

The curable composition may contain general additives such as an ultraviolet absorber, a flow control agent, a surfactant,
An antistatic agent or the like can be added.

As a method for forming a hard coat film, a dipping method, a spin coating method, a spray method, a flow method, a doctor blade method, or the like can be employed.

Before forming the coating film, it is preferable to subject the surface of the cover glass substrate 2 to high-voltage discharge such as corona discharge or microwave treatment in order to improve the adhesion.

The hard coat film 3 can be obtained by curing the formed coating film with heat, ultraviolet light, electron beam or the like.

Although the method of forming the hard coat film 3 described above is a method of forming a coating film, the hard coat film 3 can be formed by hot stamping.
The hot stamping is a method of transferring the decorating material from the transfer foil (film) coated with the decorating material to the cover glass substrate 2 by heating and pressing. As a decorating material, a transfer foil coated with a curable composition capable of forming a hard coat film composed of an organic thin film by ultraviolet irradiation is commercially available. The hot stamping is excellent in productivity of the hard coat film 3 and can be transferred onto a curved surface, so that a hard coat film can be formed on the outer surface side of the cover glass.

As one method of hot stamping, there is an in-mold molding method. This in-mold molding method
A roll-shaped transfer foil on which a decorating material is preliminarily printed is intermittently passed through an injection molding die for molding the cover glass base material 2 in accordance with a molding cycle, and the decorating material is simultaneously injected with the injection molding. This is a method of transferring to a molded cover glass substrate 2 using pressure and heat. Since hot stamping can be performed simultaneously in the molding cycle of the cover glass substrate 2, the secondary step of hot stamping can be reduced, and the efficiency is good. Also, it can be transferred onto a curved surface. After the molding, the curable film is transferred to the cover glass substrate 2 from the transfer foil. The hard coat film 3 can be obtained by curing the curable film with, for example, an ultraviolet ray or an electron beam. As a technique for transferring a film on which such a hard coat film is formed in advance, the IMD method of Nissha Printing Co., Ltd. can be exemplified.

The thickness of the hard coat film 3 is 0.05
The range is preferably about 30 μm. If it is too thin, basic performance may not be exhibited, while if it is too thick, optical distortion may occur.

In order to improve the adhesion between the hard coat film 3 and the antireflection film 4, it is desirable that the surface of the hard coat film 3 is surface-treated. Examples of the surface treatment method include an acid treatment, an alkali treatment, an ultraviolet irradiation treatment, a plasma treatment by a high-frequency discharge in an argon or oxygen atmosphere, and an ion beam irradiation treatment with argon, oxygen or nitrogen.

The antireflection films 4 and 5 are composed of a single layer or a multilayer of an inorganic film and an organic film. Antireflection film 4 on the outer surface
The antireflection film 5 on the inner surface side may have the same configuration or a different configuration. For example, the anti-reflection film 4 on the outer surface may have a multilayer structure, and the anti-reflection film 5 on the inner surface may be simplified to have a single-layer structure.

As the material of the inorganic coating, SiO ₂ , Si
O, ZrO ₂ , TiO ₂ , TiO, Ti ₂ O ₃ , Ti ₂ O ₅ ,
Al ₂ O ₃ , Ta ₂ O ₅ , CeO ₂ , MgO, Y ₂ O ₃ , Sn
Inorganic substances such as O ₂ , MgF ₂ and WO ₃ can be mentioned, and these can be used alone or in combination of two or more.
Among them, SiO ₂ , Z which can be vacuum-deposited at low temperature,
rO ₂ , TiO ₂ and Ta ₂ O ₅ are preferred. In the case of a multilayer structure, the outermost layer is preferably made of SiO ₂ .

As the multilayer film of the inorganic film, the total optical film thickness of the ZrO ₂ layer and the SiO ₂ layer from the cover glass substrate 2 side is λ.
/ 4, the optical thickness of the ZrO ₂ layer is λ / 4, and the uppermost layer is Si.
An example is a four-layer structure in which the O ₂ layer has an optical thickness of λ / 4. Here, λ is a design wavelength, usually 520n
m is used.

Examples of the method for forming the inorganic film include a vacuum deposition method, an ion plating method, a sputtering method, and a CV method.
Method D, a method of precipitating by a chemical reaction in a saturated solution, and the like can be adopted.

The material of the organic film is, for example, FFP (tetrafluoroethylene-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), ET
FE (ethylene-tetrafluoroethylene copolymer) and the like can be cited, and are selected in consideration of the refractive index of the cover glass substrate and the hard coat film. The film can be formed by a coating method excellent in mass productivity such as a spin coating method and a dip coating method, in addition to a vacuum evaporation method.

Further, the hard coat film 3 and the antireflection film 4 can be simultaneously formed by in-mold molding. That is, using a transfer foil on which a hard coat film capable of forming a hard coat film by curing and an antireflection film 4 are formed, the transferred hardenable film is cured to form the antireflection film 4 and the hard coat film 3. Cover glass can be obtained. Thereby, simultaneously with the formation of the cover glass substrate 2,
The coating on which the hard coat film 3 can be formed and the antireflection film 4 can be transferred, and the manufacturing process can be shortened.

It is desirable that at least the surface of the antireflection film 4 provided on the outer surface side be subjected to a water / oil repellent treatment. By performing the water / oil repellent treatment, properties such as antifouling property, water repellency, and oil repellency can be imparted to the surface of the antireflection film 4, and the durability of the antireflection film 4 can be increased.

The water / oil repellent treatment method is to coat the surface of the antireflection film using an organic compound having a hydrophobic group and a reactive group which undergoes a condensation reaction with a SiOH group in one molecule, or to form a film by vacuum evaporation or the like. And processing. In this case, the outermost layer of the antireflection film 4 is preferably made of SiO ₂ .

[0077] As the organic compound having a reactive group with the hydrophobic group, for example _{Rf a -Si-X 4-a} ( wherein, Rf
Is a polyfluoroalkyl group or a polyfluoroether group or an organic group containing these groups, X is an alkoxy group, a halogen atom or an amino group, and a is an integer of 1 to 3). Can be exemplified.

When the decorative portion 11 that does not transmit light is provided on the peripheral portion of the cover glass or the like, it may be provided on either the outer surface side or the inner surface side. The decorative part 11 can be formed by, for example, a plating method, hot stamping, silk printing, or in-mold molding.

The cover glass 1 of the first embodiment shown in FIG. 3 is provided with an anti-reflection film 4 on the outer surface of a cover glass substrate 2 and an anti-reflection film 5 on the inner surface. The antireflection film 4 provided on the outer surface side solves the problem that the external light is reflected on the surface 12 of the cover glass 1 and the display flickers, and the illumination is reflected on the cover glass and the display is difficult to see.
By improving the transmittance of external light, the visibility of the display of the liquid crystal display device can be improved. Further, the antireflection film 5 provided on the inner surface side allows the reflected light reflected from the liquid crystal display device to pass through the cover glass with almost no attenuation, thereby improving the reflectance of the liquid crystal display device. The same effect can be obtained, and the display of the liquid crystal display device can be made bright and easy to see. For example, when no antireflection film is provided, the light transmittance is about 92%, but when the antireflection film is provided on both surfaces of the cover glass, the light transmittance can be 98% or more. Further, since the hard coat film 3 is interposed between the outer surface side anti-reflection film 4 and the cover glass substrate 2, the adhesion of the anti-reflection film 4 is improved, and the anti-reflection film 4 is hardly peeled off. Moreover, the hard coat film 3 makes it difficult for the cover glass 1 to be damaged.

FIG. 4 is a sectional view showing the sectional structure of each of the second and third embodiments of the cover glass of the present invention.

The cover glass 1b according to the second embodiment shown in FIG. 4A has a primer layer 6 on the outer surface of a cover glass substrate 2 made of a transparent resin and formed in the shape of a cover glass.
Is provided, the hard coat film 3 is provided on the primer layer 6, the antireflection film 4 is provided on the hard coat film 3, and the antireflection film 5 is provided directly on the inner surface side of the cover glass substrate 2. It has a structure. The difference from the cover glass 1 of the first embodiment is that the primer layer 6 is interposed between the cover glass substrate 2 and the hard coat film 3.

The cover glass 1b of the second embodiment is
By providing the primer layer 6, the hard coat film 3
The adhesion of the anti-reflection film 4 to the transparent resin cover glass substrate 2 can be improved, and the impact resistance of the cover glass 1 can be improved.

The primer layer 6 is preferably made of a polyurethane resin. The polyurethane resin primer layer 6 is a coating film using a two-component primer composition containing an active hydrogen-containing compound and a polyfunctional isocyanate compound or a primer composition of an aqueous solution in which an aqueous polyurethane resin is dispersed in water. Can be formed.

Examples of the active hydrogen-containing compound include acrylic polyols, (poly) alkylene glycols, poly (alkylene adipates) and the like.

The acrylic polyol is a copolymerized acrylic resin of an acrylic monomer having a hydroxyl group and a monomer copolymerizable with the acrylic monomer having a hydroxyl group.

Examples of the acrylic monomer having a hydroxyl group as a raw material of the acrylic polyol include 2-hydroxyethyl acrylate, 3-chloro-2-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, and 2-hydroxyethyl methacrylate. , 2-hydroxypropyl methacrylate, 6-hydroxyhexyl methacrylate, 5,6-
Dihydroxyhexyl methacrylate and the like,
These may be used alone or in combination of two or more.

The monomers copolymerizable with the acrylic monomer having a hydroxyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth)
Acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, isoamyl (meth) acrylate, trifluoroethyl (meth) Acrylate, benzyl (meth)
Acrylate, 2-n-butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, cinnamyl (meth) acrylate , Cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, furfuryl (meth)
Acrylate, hexafluoroisopropyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-
Methoxybutyl (meth) acrylate, 2-nitro-2-
Methylpropyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2-phenylethyl (meth) acrylate, phenyl (meth) acrylate, tetrahydrofurfuryl (Meth) acrylate, tetrapyranyl (meth) acrylate, acrylic acid,
Examples include acrylic monomers such as methacrylic acid, and ethylenic monomers such as acrylonitrile, vinyl acetate, vinylpyridine, vinylpyrrolidone, methylcrotonate, maleic anhydride, styrene, and α-methylstyrene. In addition, (meth) acrylate means acrylate or methacrylate.

The acrylic polyol can be obtained by polymerizing the acrylic monomer having a hydroxyl group and a monomer copolymerizable therewith with a known polymerization method such as a bulk polymerization method, a solution polymerization method, and an emulsion polymerization method. .

Examples of the (poly) alkylene glycols include ethylene glycol, propylene glycol, butanediol, polyethylene glycol and polypropylene glycol.

Examples of the poly (alkylene adipates) include poly (diethylene adipate) and poly (hexamethylene adipate).

On the other hand, as the polyfunctional isocyanate compound, an aliphatic diisocyanate compound and an alicyclic diisocyanate are preferable from the viewpoint of weather resistance. For example, isophorone diisocyanate, dicyclohexylmethane diisocyanate, norborane diisocyanate, and hexamethylene diisocyanate are preferable.

The two-pack primer composition is prepared by dissolving an active hydrogen-containing compound and a polyfunctional isocyanate compound in an aprotic solvent.

On the other hand, the aqueous polyurethane resin is, for example, an acrylic polyol, another polyol as required, a compound having a carboxyl group and at least two active hydrogens, a polyfunctional isocyanate compound and a catalyst.
After reacting in an organic solvent using a stoichiometric excess of a polyfunctional isocyanate compound with respect to active hydrogen to produce an acrylic-modified urethane prepolymer having a carboxyl group and a terminal isocyanate group, neutralization The aqueous urethane prepolymer is dispersed in water and neutralized with an agent, and then dispersed in water, and further polymerized with a chain extender to produce a self-emulsifying aqueous acryl-urethane copolymer composition.

Also, without using a compound having a carboxyl group and at least two active hydrogens, an acrylic polyol, if necessary, other polyols, a polyfunctional isocyanate compound and a catalyst are stoichiometrically excess with respect to the active hydrogens. After producing an acrylic-modified urethane prepolymer having an isocyanate group at a terminal by reacting in an organic solvent using the polyfunctional isocyanate compound of the above, the urethane prepolymer is dispersed in water using a surfactant, and further chain extension. Water-based acrylic of forced emulsification type by polymerizing with an agent
There is a method for obtaining a urethane copolymer composition.

Further, as another method for obtaining a water-based polyurethane resin, an acrylic polyol containing a compound having a carboxyl group and at least two active hydrogens and a polyfunctional isocyanate compound may be used in an equivalent ratio of isocyanate groups to active hydrogen groups. Is reacted at a ratio of 0.8 / 1 to 1.2 / 1, a carboxyl group is neutralized with a neutralizing agent, and then the polyurethane is dispersed in water.

Furthermore, for example, an acrylic monomer is emulsion-polymerized in the presence of an aqueous polyurethane resin to form a core.
There is a method of obtaining a composite emulsion which is a composite of an acrylic polyol having a shell structure and an aqueous polyurethane resin.

In this method, for example, a polyol containing a compound having a carboxyl group and at least two active hydrogens and a polyfunctional isocyanate compound are prepared by adjusting the equivalent ratio of isocyanate groups to active hydrogen groups to 0.8 / 1 to 1.2. / 1 and neutralize the carboxyl groups with a neutralizing agent.
The polyurethane is dispersed in water. Acrylic monomer is mixed in the aqueous medium in which the water-dispersed polyurethane is present,
The aqueous polyurethane resin having a core-shell structure can be obtained by polymerization with a polymerization initiator.

Examples of polyols other than acrylic polyols include polyester polyols, polycarbonate polyols and polyether polyols, and one of these polyols can be used alone or in combination of two or more. .

Compounds having a carboxyl group and at least two active hydrogens in the molecule include, for example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid,
2,2-dimethylolvaleric acid, dioxymaleic acid,
2-dimethylolbutanoic acid and the like can be mentioned.

The compounding amount of the compound having a carboxyl group and at least two active hydrogens is such that the content of the carboxyl group in the resin is from 0.3 to 5% by weight, particularly from 0.5 to 1.5% by weight. A range is preferred.

As the catalyst, one or more of dibutyltin dilaurate, stannasoctoate, dibutyltin-2-ethylhexoate, triethylamine, triethylenediamine, N-methylmorpholine and the like can be used.

Examples of the neutralizing agent include amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine and triethanolamine, potassium hydroxide, sodium hydroxide and ammonia.

Examples of the chain extender include low molecular weight polyfunctional alcohols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol and sorbitol;
Furthermore, ethylenediamine, propylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, low molecular weight polyamines such as triethylenetetramine, and the like, and these alone or in combination of two or more. They can be used in combination.

The structure other than the primer layer 6 of the cover glass 1b of the second embodiment shown in FIG. 4A is the same as that of the first embodiment, and a description thereof will be omitted.

A cover glass 1c according to the third embodiment shown in FIG. 4B has a hard coat film 3 provided on the outer surface side of a cover glass substrate 2, and an antireflection film 4 provided on the hard coat film 3. It has a structure in which an antireflection film is not provided on the inner surface side of the cover glass substrate 2. Compared with the cover glass 1 of the first embodiment, the structure is such that the antireflection film 5 on the inner surface side is omitted and the cover glass 1 can be manufactured at low cost.

Since the antireflection film on the inner surface side is not provided, the light transmittance of the cover glass 1c is slightly inferior to that of the cover glass 1 of the first embodiment, but the display flickers and the illumination is reflected on the cover glass. The problem that the display is difficult to see because the antireflection film 4 on the outer surface side has been eliminated is excellent in the visibility of the display device.

In the above description, the cover glass in which the anti-reflection film is formed directly on the cover glass substrate 2 or the hard coat film 3 is shown. Use is more cost effective.

FIG. 5 shows a cross-sectional structure of a cover glass using an anti-reflection film. FIG. 5 (a) shows the cover glass of the fourth embodiment, and FIG. 5 (b) shows the cover glass of the fifth embodiment. Show.

A cover glass 1d according to the fourth embodiment shown in FIG. 5A has a hard coat film 3 provided on the outer surface side of a cover glass substrate 2 formed in the shape of a cover glass. An anti-reflection film 4 is formed on 3. On the other hand, an antireflection film 7 is adhered to the inner surface side of the cover glass substrate 2. It has a structure in which the antireflection film 5 on the inner surface side of the cover glass 1 of the first embodiment is replaced with an antireflection film 7.

The anti-reflection film 7 includes a base film 71
An adhesive layer 72 is provided on one surface side, and an antireflection film 73 is provided on the other surface side, and is adhered to the inner surface side of the cover glass substrate 2 via the adhesive layer 72. Therefore, the antireflection film 73 is provided on the cover glass substrate 2 via the base film 71 of the antireflection film 7.

The antireflection film 7 is relatively hard and poor in flexibility, and at present it is difficult to stick it on a curved surface, and there is a limitation in use that it can be applied only to a flat surface or a cylindrical surface.

Therefore, if the outer surface of the cover glass substrate 2 has a curved shape, it is difficult to adhere to the outer surface side, so that the antireflection film 7 is flat or almost flat. It is preferable to adopt a structure shown in FIG. 5A in which the antireflection film 4 is provided on the outer surface side of the cover glass substrate 2 by vacuum evaporation or the like.

Examples of the material of the base film 71 constituting the antireflection film 7 include polyester, polyethylene terephthalate (PET), polybutylene terephthalate, polymethyl methacrylate (PMMA), acrylic, polycarbonate, polystyrene, triacetate, and polyvinyl alcohol. And transparent films of polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyurethane and cellophane. The thickness of the base film 71 is 1 μm to 10
A range of 0 μm is usual.

The antireflection film 73 provided on the base film 71 can have a single-layer or multilayer structure of an organic film or an inorganic film. In the case of a multilayer structure, it is desirable to alternately form high-refractive-index films and low-refractive-index films from the base film 71 side.

As the high refractive index film, for example, ITO (tin indium oxide), ZnO, and Zn doped with Al are used.
O, TiO ₂ , SnO ₂ , and ZrO can be used.

As the low refractive index film, SiO ₂ , MgF ₂ ,
Examples include inorganic films such as Al ₂ O ₃ and organic films such as FFP (tetrafluoroethylene-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), and ETFE (ethylene-tetrafluoroethylene copolymer). Can be.

As a method of forming such an antireflection film 73 on the base film 71, a method of cutting out a large-area sheet or winding it up on a roll while depositing, sputtering, ion plating, or a CVD method is used. It can be formed by a dry method such as, for example, or a wet method by coating a film containing an organic substance as a main component.

Examples of a commercially available anti-reflection film include, for example, a product name AR using a fluororesin as the anti-reflection film 73.
CTOP (manufactured by Asahi Glass Co., Ltd.) is available. AR-PET (trade name) having an antireflection film 73 formed by a vacuum evaporation method
75 (manufactured by Sumitomo Chemical Co., Ltd.).

The anti-reflection film 7 is advantageous in terms of productivity and cost as compared with the case where an anti-reflection film is formed directly on a cover glass because the anti-reflection processing can be performed efficiently. In addition, it is possible to provide a hard coat film on the antireflection film 7 in advance, or to perform a water / oil repellent treatment at a low cost. In addition, the step of attaching the antireflection film 7 to the cover glass substrate 2 can be efficiently performed by an automated machine. Therefore, the production cost can be reduced by attaching the antireflection film 7 instead of providing the antireflection film directly on the inner surface of the cover glass 1. In addition, unlike the case of sticking to the outer surface side, by sticking to the inner surface side of the cover glass substrate 2, the appearance of the antireflection film 7 does not matter so much. There is also an advantage that can be simplified.

The cover glass 1e of the fifth embodiment shown in FIG. 5 (b) can be applied to both the outer surface and the inner surface of the cover glass substrate 2 when the outer surface of the cover glass substrate 2 is flat or cylindrical. An example in which antireflection films 7, 7 'are provided is shown. These antireflection films 7 and 7 ′ also have an adhesive layer 72 provided on one side of the base film 71 and an antireflection film 73 provided on the other side. The anti-reflection film 7 'on the outer surface is provided with an anti-reflection film 7 for imparting abrasion resistance.
3 and a base film 71 with a hard coat film 74 interposed therebetween. This hard coat film 74 can be omitted as in the embodiment.

It is recommended that the base film 71 be made of a hard and hardly scratchable material so that the antireflection film 7 'on the outer surface side is hardly scratched.

Further, when the antireflection film 7 'is adhered to the outer surface, a step of hiding the outer peripheral end surface of the cover glass 1e or a step of performing an end surface treatment of the antireflective film 7' to finish the end surface neatly is required. May be.

As shown in FIG. 1, the cover glass 1 of the portable device is often provided with a decorative portion 11 such as a border decoration or a character. In the cover glass having a structure to which the antireflection film 7 of the present invention is adhered, by providing the decorative portion 11 on the antireflection film in advance, the step of separately providing a decorative portion is omitted, and the antireflection function is provided at low cost. Decoration part 11
Can be produced.

FIGS. 6A and 6B show an example of an antireflection film provided with such a decorative portion, wherein FIG. 6A is a plan view and FIG. 6B is a cross-sectional view along the line BB '. FIG.
As shown in (a), a decorative portion 11 is provided on the outer peripheral portion of the antireflection film 7a. As shown in FIG. 6B, a decorative portion 11 formed by means such as printing is provided on one surface side of the base film 71.
1, an adhesive layer 72 is provided, and an antireflection film 73 is provided on the other surface side. In addition to these layer configurations, a hard coat film may be interposed between the base film 71 and the antireflection film 73.

Next, the manufacturing process of the cover glass to which the antireflection film of the present invention is adhered will be described. The antireflection films 7 and 7 ′ are supplied in a state where a protective film is stuck on the antireflection film 73 side and a release film is stuck on the adhesive layer 72 side. For this reason, it is more advantageous to perform antireflection processing on curved surfaces such as vapor deposition later with the protective film attached to the antireflection film after performing the antireflection film sticking step first. is there. However, when there is a step of applying heat such as vapor deposition and the heat resistance of the antireflection film is low and there is a possibility that cracks or the like may occur, the step of applying heat is performed before attaching the antireflection film. When the antireflection film is formed on the cover glass substrate 2, for example, when the surface on which the antireflection film is formed is subjected to, for example, acid cleaning or alkali cleaning, the antireflection film is formed. It is desirable to attach an antireflection film later. It is desirable that the protective film of the anti-reflection film be left attached during transportation and storage, and that the protective film be peeled off when assembled to a portable device.

The general manufacturing process of the cover glass 1d shown in FIG. 5A in which the antireflection film 7 is adhered on the inner surface side and the hard coat film 3 and the antireflection film 4 are formed on the outer surface side is as follows. For example, the cover glass substrate 2 provided with an uncured hard coat film on the outer surface side is formed by in-mold molding, and the hard coat film 3 cured by irradiating the cover glass substrate 2 with radiation such as ultraviolet rays. obtain. After that, the release film is peeled off from the antireflection film 7 and attached to the inner surface of the cover glass substrate 2. Further, an anti-reflection film 4 is formed by vacuum evaporation or the like while a protective film (not shown) is stuck to the anti-reflection film 7, and finally, the anti-reflection film 4 is subjected to a water-repellent treatment to cover the cover glass 1d. Get.

In the case of the cover glass 1e in which the anti-reflection film shown in FIG. 5B is adhered to both sides, the cover glass substrate 2 is formed by a usual forming method, and then, if necessary, the cover glass base 2 is formed. After the surface treatment of the material 2, an antireflection film 7 ′ having a hard coat film 74 is attached to the outer surface of the cover glass substrate 2,
Can be manufactured by sticking an antireflection film 7 to the inner surface of the substrate.

[0128]

<Example 1> A resin film having a base coated with an ultraviolet-curable organic hard coat film was subjected to injection molding by an in-mold molding method in which injection molding was performed inside a mold, and a hard surface was formed on the outer surface side. A cover glass to which the coat film was transferred was formed. The base material is acrylic resin (PM
MA). After peeling off the resin film, the hard coat film was cured by irradiating ultraviolet rays.

The obtained cover glass with a hard coat was subjected to antireflection processing on both sides by a vacuum evaporation method. The film configuration of the antireflection processing is such that the total optical film thickness of the ZrO ₂ layer and the SiO ₂ layer from the substrate side is λ / 4, the ZrO ₂ layer is λ / 4, and the uppermost layer is S
The iO ₂ layer was set to λ / 4. (Λ = 520 nm)
-(Perfluorooctyl) ethyltriaminosilane was deposited by heating under vacuum.

Example 2 Acrylic resin (PMMA) was formed into a cover glass by ordinary injection molding. Hard coat processing is carried out using a commercially available acrylic ultraviolet curing hard coat liquid (Diabeam UK-6 manufactured by Mitsubishi Rayon Co., Ltd.).
074), a cover glass was immersed and pulled up to form a coating, and the coating was cured by irradiation with ultraviolet rays. Then, antireflection processing and water rubbing processing were performed in the same manner as in Example 1.

Example 3 Example 2 was repeated except that the coating agent for the hard coat process was changed to a silicon-based UV-curable hard coat liquid (UVHC8553 manufactured by Toshiba Silicone Co., Ltd.).
A cover glass was prepared and surface-treated in the same manner as described above.

Example 4 Acrylic resin (PMMA) was formed into a cover glass by ordinary injection molding. The hard coat processing was performed by applying a hard coat liquid in which a metal oxide was dispersed in a silane compound having a polymerizable group and a hydrolyzable group by a spin coating method, and then baked at 125 ° C. for 30 minutes. The hard coat liquid was prepared by the following method.

In a reaction vessel equipped with a stirrer, 300 g of 2-ethoxyethanol, 470 g of colloidal silica dispersed with 2-methoxyethanol (trade name: Oscar 1832, manufactured by Catalyst Chemical Industry Co., Ltd.), α-glycidoxypropyltrimethoxysilane 185 g, 0.03 g of a flow control agent and 50 g of a 0.05N hydrochloric acid aqueous solution were added, and the mixture was stirred at room temperature for 2 hours to obtain a coating liquid. Thereafter, antireflection processing and water rubbing processing were performed in the same manner as in Example 1.

Example 5 Acrylic resin (PMMA) was formed into a cover glass by ordinary injection molding. After that, the same anti-reflection processing and water-repellent and oil-repelling processing as in Example 1 were directly performed on the molded product without performing the hard coating processing.

<Comparative Example 1> In the same manner as in Example 1, a resin film having a base coated with an ultraviolet-curable organic hard coat film was subjected to injection molding by an in-mold molding method for performing injection molding inside a mold. Then, a cover glass having a hard coat film transferred to the outer surface side was prepared. The material of the base material was acrylic resin (PMMA). After peeling off the resin film, the hard coat film was cured by irradiating ultraviolet rays. No anti-reflection processing or water rubbing processing was performed.

Each of the cover glasses obtained in Examples 1 to 6 was tested by the following method. Table 1 shows the results. (A) Abrasion resistance A 1 kg load was applied to Bonstar # 0000 steel wool (manufactured by Nippon Steel Wool Co., Ltd.), the surface was rubbed for 10 reciprocations, and the degree of damage was visually evaluated in the following stages. : There is no scratch in the area of 1 cm × 3 cm. B: 1 to 10 scratches are made in the above range. C: 10 to 100 scratches are made in the above range. D: 100 or more scratches are made. (B) Adhesion A cross-cut tape test according to JIS D-0202 was performed, and a sheet with no surface treatment film peeled was rated as good. (C) Spectral Reflectance The average reflectance in the visible light wavelength band was measured with a spectrophotometer (U-3500, manufactured by Hitachi, Ltd.).

[0137]

[Table 1]

According to the results shown in Table 1, in Comparative Example 1 in which the antireflection film was not provided, the reflectance was as large as 4.0%, the reflection on the cover glass was large, and the light transmittance was poor. On the other hand, in Examples 1 to 5 in which the antireflection films were provided on both surfaces of the cover substrate, the reflectance was reduced to 1/8, and the light transmittance was significantly improved.
Further, when a hard coat film is provided between the antireflection film on the outer surface side and the cover glass substrate (Examples 1 to 4), the abrasion resistance and adhesion are higher than when no hard coat film is provided (Example 5). It was recognized that it became better.

Example 6 Injection molding was performed by an in-mold molding method in which a resin film in which a base film was coated with an ultraviolet-curable organic hard coat film was placed inside a mold and injection molding was performed. Then, a cover glass substrate on which the hard coat film was transferred was prepared. The material of the base material was acrylic resin (PMMA). The shape of the cover glass substrate is a convex lens shape in which the outer surface is spherical and the inner surface is flat. After peeling off the resin film, the hard coat film was cured by irradiating ultraviolet rays.

A commercially available film with an anti-reflection film (AR-PET75: manufactured by Sumitomo Chemical Co., Ltd.) cut out to a size larger than the cover glass base material was adhered to the inner surface of the cover glass base material without gaps, and the portion protruding into the periphery Was cut off.

The outer surface side of the cover glass substrate was subjected to antireflection processing by a vacuum evaporation method. The film configuration of the antireflection processing is such that the total thickness of the ZrO ₂ layer and the SiO ₂ layer from the substrate side is λ / 4, Zr
The O ₂ layer was λ / 4, and the uppermost SiO ₂ layer was λ / 4 (λ
= 520 nm).

The water-repellent treatment was performed by heating and vapor-depositing 2- (perfluorooctyl) ethyltriaminosilane as a fluorine-containing organosilicon coating agent.

The luminous transmittance of the thus obtained cover glass having an antireflection film formed on the outer surface and an antireflection film attached on the inner surface was 98.5%.

Example 7 A cover glass substrate of acrylic resin (PMMA) having a cylindrical outer surface and a flat inner surface was manufactured by injection molding. A commercially available film with an anti-reflection film (ARCTOP PFO3; manufactured by Asahi Glass Co., Ltd.) cut out to a size larger than the cover glass base material was attached to the inner surface of the cover glass base material, and the portion of the film protruding to the periphery was cut off. Subsequently, the same film was similarly attached to the outer surface, and the portion of the film protruding to the periphery was cut off.

The luminous transmittance of the thus obtained cover glass having an antireflection film adhered to both the outer surface and the inner surface was 98.5%.

<Example 8> A cover glass substrate having a flat plate shape was prepared by injection molding with an acrylic resin (PMMA), and a film with an antireflection film was attached to both sides of the cover glass substrate in the same manner as in Example 7. Was.

The luminous transmittance of the thus obtained cover glass having an antireflection film adhered to both the outer surface and the inner surface was 98.5%.

<Comparative Example 2> In the same manner as in Example 6, a resin film in which a base film was coated with an ultraviolet-curable organic hard coat film was placed inside a mold and injection molding was performed. Injection molding was performed to prepare a cover glass substrate having a hard coat film transferred to the outer surface side. The material of the base material was acrylic resin (PMMA). The shape of the cover glass substrate is a convex lens shape in which the outer surface is spherical and the inner surface is flat. After peeling off the resin film, the hard coat film was cured by irradiating ultraviolet rays.

The anti-reflection processing and the water-repellent processing were not performed. The luminous transmittance of the thus obtained cover glass not subjected to anti-reflection processing was 92%.

When the cover glasses obtained in Examples 1 to 8 and Comparative Examples 1 and 2 were incorporated into a display device and the display was compared, the cover glass of the example showed a larger display than that of the comparative example. However, it was bright, with little flicker, and easy to see.

[0151]

The cover glass of the present invention can reduce the reflection of external light, improve the light transmittance, and improve the visibility of the display device in portable equipment.

[Brief description of the drawings]

FIG. 1 is a front view of an example of a mobile phone using a cover glass.

FIG. 2 is a cross-sectional view of the cover glass of FIG. 1 taken along line AA ′.

FIG. 3 is a sectional view showing a first embodiment of the cover glass of the present invention.

FIG. 4 shows another embodiment of the cover glass of the present invention, wherein (a) shows the second embodiment and (b) shows the third embodiment.

5A and 5B are cross-sectional views showing another embodiment of the cover glass of the present invention, wherein FIG. 5A is a fourth embodiment in which an antireflection film is used on the inner surface side, and FIG. A fifth embodiment is shown.

6A and 6B show an antireflection film provided with a decorative portion, wherein FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view taken along line BB ′ of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cover glass 11 Decorative part 12 Outer surface 13 Inner surface 2 Cover glass base material 3 Hard coat film 4 Antireflection film (outer surface side) 5 Antireflection film (inner surface side) 6 Primer layer 7 Antireflection film 71 Base film 72 Adhesion Agent layer 73 Anti-reflection film 74 Hard coat film 20 Housing 21 Window 22 Frame 23 Void 30 Liquid crystal display 31 Display surface 100 Mobile phone

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H042 BA02 BA20 2H091 FA37X FB02 FB04 FC12 FC25 GA16 LA02 LA03 2K009 AA04 AA05 AA07 AA15 BB14 BB24 CC03 CC09 CC14 CC26 CC42 DD03 DD06 DD07 DD17 EE02 5G435 AA01 BB00 FF07

Claims (11)

[Claims] 1. A cover glass fixed to a window of a housing of a portable device and used for seeing through the inside of the housing, wherein the cover glass is provided on an outer surface side or on an outer surface side and an inner surface side of a transparent cover glass base material. A cover glass having an antireflection film provided on both sides. 2. The cover glass according to claim 1, wherein the anti-reflection film is provided on the cover glass substrate via a base film of the anti-reflection film. 3. The cover glass according to claim 1, wherein a hard coat film is interposed between the cover glass substrate and the antireflection film. 4. The cover glass according to claim 3, wherein the antireflection film is provided on an outer surface side of the cover glass substrate via the hard coat film, and the antireflection film is provided on an inner surface side of the cover glass substrate. A cover glass, wherein the film is provided without interposing the hard coat film. 5. The cover glass according to claim 4, wherein the anti-reflection film on the inner surface side of the cover glass base is provided on the cover glass base via a base film of the anti-reflection film. Features cover glass. 6. The cover glass according to claim 3, wherein the hard coat film is provided by hot stamping. 7. The cover glass according to claim 3, wherein the hard coat film comprises the following components (A) and (B), (A) Si and S having a particle diameter of 1 to 100 millimicrons.
one or more metal oxide fine particles selected from n, Sb, Ce, Zr, Ti and / or Si, Al, Sn, Sb, T
a, fine particles composed of two or more metal oxides selected from Ce, La, Fe, Zn, W, Zr, In and Ti, (B) a silane compound having a polymerizable group and a hydrolyzable group A cover glass obtained by applying and curing a coating composition containing, as a main component. 8. The cover glass according to claim 2, wherein
A cover glass, wherein a decorative portion is provided on the antireflection film. 9. The cover glass according to claim 3, wherein a primer layer is interposed between the cover glass substrate and the hard coat film. 10. The cover glass according to claim 1, wherein a surface of the antireflection film provided on an outer surface side of the cover glass substrate is subjected to a water / oil repellent treatment. A cover glass characterized by: 11. The cover glass according to claim 1, wherein the cover glass covers and protects a display surface of a liquid crystal display device housed in a housing of the portable device, and is used for visually recognizing the display surface. Cover glass characterized by being able to be used.