JPH10206602A - Conductive anti-reflection film - Google Patents

Abstract

(57) Abstract: An antireflection film having excellent antireflection performance for visible light, good adhesion between layers in the antireflection layer, low stress on a hard coat layer serving as a base, and electromagnetic waves. To provide a conductive antireflection film having a shielding function. An anti-reflection film in which a hard coat layer, an anti-reflection layer in which at least one or more conductive inorganic compounds having different refractive indices are sequentially laminated, and a water-repellent layer are sequentially laminated on a film. In the optical film thickness of each inorganic compound layer (∫ndx (integral section is between both surfaces of the film)),
An antireflection film, wherein the value of n in the thickness direction of the inorganic compound layer other than the layer of the conductive inorganic compound is non-uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive antireflection film applied on a polarizing film or the like provided on the surface of a display screen of a display. The present invention relates to an anti-reflection film having good adhesion between layers in the anti-reflection layer, having a small stress on a hard coat layer serving as a base, and having a function of shielding electromagnetic waves.

[0002]

2. Description of the Related Art Many displays, indoors and outdoors,
Used in an environment where external light is incident, the incident light is specularly reflected inside the display to reproduce a virtual image of the light source on the surface or to mix with display light to lower display quality.

In order to prevent these, irregularities are provided on the display screen to cause irregular reflection, or high-refractive-index and low-refractive-index materials as in the present invention are alternately and uniformly stacked in n × d. Used anti-reflection film.

[0004] In recent years, the penetration of electromagnetic waves from a drive circuit for a display screen or into the circuit through the display screen has become a problem, causing an effect on the human body or a malfunction of a machine.

[0005]

However, the method of irregularly reflecting the light may cause an image on the display to be blurred, which is not sufficient compared with the antireflection film. Further, in a laminate having a uniform value of n with respect to a normal thickness direction, a material having a high refractive index, which is a strong material even at the interface, must be used. Not only in the layer but also in the adhesion to the film substrate and the resistance difference due to the difference in stress with the hard coat layer provided for relaxing the hardness, cracks may occur, and quality may be reduced. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and it is an object of the present invention to provide excellent antireflection performance for visible light and good adhesion between layers in the antireflection layer. Another object of the present invention is to provide a conductive anti-reflection film which is an anti-reflection film having a small stress on a hard coat layer serving as a base and has an electromagnetic wave shielding function.

[0007]

According to the first aspect of the present invention,
On the film, a hard coat layer, an antireflection layer in which a refractive index is different, and an antireflection layer in which at least one or more conductive inorganic compounds are laminated, and an antireflection film in which an antifouling layer is laminated, The optical film thickness of the compound layer (a value defined as n (refractive index) × d (shape film thickness) when the refractive index and the shape film thickness are constant, 但 ndx (however, the integral section is between both surfaces of the film (x = 0 to d)), wherein the value of n in the thickness direction of the inorganic compound layer other than the conductive inorganic compound layer is non-uniform.

The invention according to claim 2 is based on the premise of the invention according to claim 1, and has a high refractive index (n) other than a layer made of a conductive inorganic compound in an antireflection layer in which an inorganic compound is laminated.
> 1.9) An electrically conductive antireflection film, wherein the material is any one of titanium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, hafnium oxide, cerium oxide, and tin oxide.

According to a third aspect of the present invention, based on the premise of the first aspect, a low refractive index of a layer other than a layer made of an inorganic compound having a conductive inorganic compound in an antireflection layer in which an inorganic compound is laminated is provided. Rate (n <1.6) material is silicon oxide,
A conductive anti-reflection film characterized by being one of magnesium fluoride and calcium fluoride.

The invention according to claim 4 is based on the premise of claim 1, wherein the conductive inorganic compound is a transparent conductive material mainly containing indium oxide or a transparent conductive material mainly containing tin oxide. The conductive anti-reflection film is a conductive material or a transparent conductive material mainly composed of zinc oxide.

The invention described in claim 5 is the first and fourth aspects of the present invention.
A conductive anti-reflection film, characterized in that a conductive inorganic compound is formed by sputtering on the premise of the described invention.

According to a sixth aspect of the present invention, there is provided the conductive antireflection film according to the first aspect, wherein the hard coat layer has a light scattering property.

According to a seventh aspect of the present invention, there is provided the conductive anti-reflection film according to the first aspect, wherein the number of the anti-reflection layers formed by laminating the inorganic compound is two or more. .

According to an eighth aspect of the present invention, based on the first aspect, the layer made of an inorganic compound having conductivity in the antireflection layer in which the inorganic compound is laminated has a value of n in the thickness direction. It is a conductive antireflection film characterized by being low at an interface in contact with another layer.

[0015]

FIG. 1 shows an example of the conductive anti-reflection film of the present invention, which will be described in detail.

The antireflection film according to this embodiment comprises a substrate 2, a hard coat layer 3, an antireflection layer 4, and an antifouling layer 5, as shown in FIG. Further, 41 is a high refractive index material layer, 42 is a low refractive index material layer, and 43 is a transparent conductive material layer.

Incidentally, the refractive indices of 41 and 42 are non-uniform as shown in FIG. 2, and are defined as Δndx (however, the integration interval is between both surfaces of the film (x = 0 to d)). The optical film thickness is designed to take a constant value.
Regarding the refractive index of 43, it is preferable that the refractive index is uniform in order to have an electromagnetic wave shielding function. Regarding the adhesiveness, which is the main feature of the present invention, even if the transparent conductivity is uniform, there is no effect since the material layer is composed of a non-uniform layer on both sides.

It is desirable that the hard coat layer 3 in the present invention has transparency and the refractive index of the substrate is equal to the refractive index. However, the layer need not be a layer having a thickness of 5 μm or more. As the material, any material may be used as long as it satisfies the required properties such as adhesion and hardness, and any curing method may be used. Examples of the material include ultraviolet-curable acrylic resins and silicone resins. Can be

Further, the material for scattering light is preferably a transparent powder for a hard coat agent. As the transparent material, for example, a transparent pigment can be used. Examples of such a transparent pigment include titanium oxide and silicon oxide. , Zinc oxide, inorganic compounds such as aluminum oxide, inorganic salts such as barium sulfate,
And fluorides such as magnesium fluoride and calcium fluoride. Examples of the transparent powder include resin powders such as polydivinylbenzene, polystyrene, and polytetrafluoroethylene, hollow beads composed of these resins, and powders obtained by subjecting the surfaces of these resins or the hollow beads to surface treatment. Can also be used. Such a transparent powder resin may be any one having an average particle diameter of an appropriate size in the transparent resin layer, and is preferably ~
About 3 μm is desirable. These are smooth to the substrate,
In addition, it is applied uniformly, and the method may be any method.

The substrate 2 in the present invention may be any transparent plastic film, and is appropriately selected according to the purpose. If used on the surface of a display, a material having no birefringence is required, and examples thereof include polycarbonate, triacetyl cellulose, polyether sulfone, and polymethyl acrylate. It does not matter. The thickness is selected according to the application.

The antifouling layer 5 in the present invention protects the antireflection layer 4 of the present invention and enhances the antifouling performance, and may be made of any material as long as it meets performance requirements. I do not care. Further, the layer may be formed by any method. The thickness must be set so as not to impair the function of the antireflection layer 4, and is preferably 20 nm or less, more preferably 10 nm or less. As the material, a compound having a hydrophobic group is preferable, and examples thereof include perfluorosilane and fluorocarbon. Depending on the material, physical vapor deposition such as vapor deposition and sputtering, CV
A chemical vapor deposition method such as D can be used.

In the present invention, the antireflection layer 4 exhibits its function by alternately laminating high-refractive-index materials 41 and low-refractive-index materials 42 with a predetermined optical film thickness. Note that, in a general definition, the value is defined as n (refractive index) × d (shape film thickness) when the refractive index and the shape film thickness are assumed to be constant. , ∫ndx
(However, the integration interval is a value defined as the distance between both surfaces of the film (x = 0 to d)). The high refractive index material 41 is defined as n> 1.
9 and the low-refractive-index material 42 has n <1.6. The number of layers is not limited as long as one layer satisfies the necessary conditions. However, the wavelength in the visible region where the reflectance is 0.5% is narrow, and a wavelength region having a reflectance prevention effect is obtained by stacking two or more layers. It can be spread, and 4-5 layers are preferred. Although the material is limited in claim 2 or claim 3, any other material may be used as long as the adhesion between the materials, that is, the stress between the layers can be relaxed (canceled).

As a film forming method for carrying out the present invention, that is, for making n non-uniform, a method in which film-forming particles can be obliquely incident on a substrate is preferable. A method capable of forming a film by utilizing is preferred. Further, n can be changed depending on the amount of the introduced gas. That is, the vapor deposition method is more preferable than the sputtering method. At this time, reactive vapor deposition or assist vapor deposition using plasma, ion beam, or the like may be performed as appropriate. Furthermore, a CVD method in which the gas composition is appropriately changed may be used, without damaging the film base material.
Any film formation method may be used as long as the desired performance can be achieved.

The transparent conductive material layer in the present invention is a transparent conductive material mainly composed of indium oxide, tin oxide and zinc oxide, and is obtained by adding a small amount of metal or semiconductor to these. So-called ITO doped with tin is known for indium oxide, antimony is known for tin oxide, and aluminum is known for zinc oxide. As for the electromagnetic wave shielding function, there is a relationship between the resistance value of the layer of the transparent conductive material and the shielding function as shown in the following equation. Electromagnetic wave shielding effect (dB) = 20 × log (Ei / Et) (1) where Ei is the electric field intensity of the electromagnetic wave incident on the electromagnetic wave shielding material, and Et is the electric field transmitted through the electromagnetic wave shielding material. Strength. Therefore, the resistance value in the present invention is 1
It is desirable that the resistance is not more than 00Ω / □. More preferably, it is desirably 50Ω / □ or less.

In the present invention, the reason why the sputtering method is used for forming the transparent conductive material layer is to reduce the particle size and the interface between the particles to reduce the resistance value. Other than the sputtering method, the CVD method is also suitable, but there is a problem in the method of controlling the thickness of the film. Furthermore, in the vapor deposition method, the substrate cannot be exposed to a high temperature because it is plastic, and the resistance can be reduced. Have difficulty. In the sputtering method, any method may be used, and reactive sputtering, ordinary sputtering, magnetron use, direct current, and alternating current may be used.

[0026]

EXAMPLE Titanium dioxide was used as the high refractive index material 41, silicon dioxide was used as the low refractive index material 42, and ITO (5% by weight of tin oxide) was used as the conductive material 43.
41 and 42 were prepared by vapor deposition, and 43 was prepared by DC magnetron sputtering.
Micro-gravure coating was performed using triacetyl cellulose as the substrate 2 and an ultraviolet-curable acrylic resin as the hard coat layer 3. Titanium dioxide, IT
One layer of O and two layers of silicon dioxide were formed at the following nd values. SiO ₂ / ITO / SiO ₂ / TiO ₂ // hard coat layer λ / 4 λ / 4 λ / 8 λ / 8 Optical film thickness = 140 140 70 70 (nm) λ = 550 nm Regarding SiO ₂ and TiO ₂ , FIG. N
Was adjusted to be non-uniform. These films were made non-uniform by changing the angle of incidence of the particles on the substrate when formed by the plasma-assisted vapor deposition method. As an antifouling layer, perfluorosilane was formed to a thickness of about 5 nm by a CVD method.

FIG. 3 shows the visible spectrum of the conductive anti-reflection film. The reflectance at 550 nm is 0.5
%Met. Further, when left in an atmosphere of 60 ° C. and a relative humidity of 90%, not only changes in appearance and performance,
No cracking was observed. Furthermore, the resistance value of the ITO prepared in the present invention was 80Ω / □, and the electromagnetic wave shielding effect was measured to be −20 dB.

For comparison, when a film was formed with a constant incident angle, cracks occurred when the film was left in the same manner.

[0029]

According to the present invention, the value of n in the thickness direction of the conductive anti-reflection film in the thickness direction of each inorganic compound layer having a different refractive index is obliquely incident or gas. As a result of devising the supply amount or the film forming method, the non-uniformity results in excellent resistance and stress relaxation. The interface portion with other layers in FIGS. 2 and 3 acts to relieve stress and strengthen adhesion, thereby increasing the effect.

By providing a layer of a transparent conductive material having a low resistance value, an electromagnetic wave shielding effect can also be imparted, which has an anti-reflection effect and an electromagnetic wave shielding effect, and has an unprecedented conductive reflection characteristic having the above characteristics. It is a prevention film.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conductive anti-reflection film according to an embodiment of the present invention.

FIG. 2 is a sectional view of a portion according to the embodiment of the present invention.

FIG. 3 shows a spectrum according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Conductive antireflection film 2 ... Base material 3 ... Hard coat layer 4 ... Conductive antireflection layer 41 ... High refractive index material layer 42 ...
Low refractive index material layer 43: transparent conductive material layer 5: antifouling layer

Claims (8)

[Claims] 1. An anti-reflection film in which a hard coat layer, an antireflection layer in which at least one layer of an inorganic compound having a different refractive index and a conductivity is laminated, and an antifouling layer are sequentially laminated on a film. And the optical film thickness of each inorganic compound layer (n (refractive index) × d when the refractive index and the shape film thickness are constant)
(Shape film thickness), n and d in a minute section
Wherein the value of n in the thickness direction of the inorganic compound layer other than the inorganic compound layer having conductivity is non-uniform. 2. A material having a high refractive index (n> 1.9) other than a layer made of an inorganic compound having conductivity in the antireflection layer formed by laminating the above inorganic compound is titanium dioxide, zirconium oxide, tantalum oxide, zinc oxide. The conductive anti-reflection film according to claim 1, wherein the conductive anti-reflection film is selected from the group consisting of indium oxide, hafnium oxide, cerium oxide, and tin oxide. 3. A low-refractive-index (n <1.6) material other than a layer made of an inorganic compound having a conductive inorganic compound in an antireflection layer in which the inorganic compound is laminated is made of silicon dioxide or fluorine. The conductive anti-reflective film according to claim 1, wherein the conductive anti-reflective film is any one of magnesium fluoride and calcium fluoride. 4. The conductive inorganic compound is a transparent conductive material mainly containing indium oxide, a transparent conductive material mainly containing tin oxide, or a transparent conductive material mainly containing zinc oxide. 2. The anti-reflection film according to claim 1, wherein: 5. The method according to claim 1, wherein said inorganic compound having conductivity is formed by sputtering.
5. The conductive anti-reflection film according to any one of items 4 and 4. 6. The conductive anti-reflection film according to claim 1, wherein said hard coat layer has a light scattering property. 7. The conductive anti-reflection film according to claim 1, wherein the number of layers of the anti-reflection layer formed by laminating the inorganic compound is two or more. 8. A layer comprising an inorganic compound having conductivity in an anti-reflection layer formed by laminating the above-mentioned inorganic compound, wherein n in the thickness direction is
2. The conductive anti-reflection film according to claim 1, wherein the value of is lower at an interface in contact with another layer.