JP3751922B2 - Antireflection film, and display device and liquid crystal display device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an antireflection film.And display device using the sameAbout.
[0002]
[Prior art]
Various displays used for computers such as liquid crystal displays, plasma displays, CRTs, word processors, televisions, display boards, display bodies such as instruments, rearview mirrors, goggles, window glass, etc. A substrate is used. And since characters, figures, and other information are read through these transparent substrates, there is a drawback that when the light is reflected on the surface of the transparent substrate, the information becomes difficult to read.
[0003]
At present, in order to solve the above disadvantages, an antireflection film comprising a base material, a hard coat layer, and a laminate formed by laminating a plurality of thin layers having different refractive indexes from each other is used, The reflection of light is prevented by sticking an antireflection film on the surface of the transparent substrate.
[0004]
As a method of forming a laminate in such an antireflection film, a method of forming by a sputtering method or a vapor deposition method is conventionally known.
[0005]
However, when a laminated body is formed by sputtering, the layer formation accuracy is good, but there is a problem that productivity is poor because the formation speed is very slow. In addition, when the laminate is formed by the vapor deposition method, there is no problem in the speed of layer formation, but the formation accuracy is poor, and thus the yield is poor, which leads to high cost of the antireflection film. .
[0006]
In order to solve the above problems, a method of forming a laminated body by a plasma CVD method has been developed at present. By forming the stacked body by the plasma CVD method, the formation speed can be dramatically increased as compared with the case of forming by a sputtering method or the like.
[0007]
[Problems to be solved by the invention]
However, when a laminated body is formed by the plasma CVD method, the following problems are newly generated.
[0008]
First, as a first problem, the adhesion between the thin layers forming the laminate is worse than when formed using a sputtering method or a vapor deposition method.
[0009]
In addition, as a second problem, when a titanium oxide layer that functions as a high refractive index layer is formed by a plasma CVD method among the thin layers forming the laminated body, the titanium oxide layer has moisture and heat resistance. It is bad and the refractive index may not be stable.
[0010]
The present invention has been made in view of the above problems, and in an antireflection film having a laminate, each thin layer constituting the laminate has good heat and heat resistance, and thus the refractive index of each thin layer is stable. Anti-reflection film with excellent optical properties, high formation speed, and excellent adhesion of each thin layerAnd display device using the sameThe main purpose is to provide
[0011]
[Means for Solving the Problems]
The invention according to claim 1 is an antireflection film comprising: a base material; a hard coat layer located on the base material; and a laminate formed by laminating a plurality of thin layers on the hard coat layer. The laminate is characterized in that it is formed by laminating a thin layer formed by a plasma CVD method and a thin layer formed by a sputtering method or a vapor deposition method.
[0012]
According to the antireflection film of the present invention, the laminate constituting the antireflection film of the present invention is formed by laminating a thin layer formed by a plasma CVD method and a thin layer formed by a sputtering method or a vapor deposition method. Therefore, productivity can be improved compared to the case where all the thin layers forming the laminate are formed by sputtering or vapor deposition, while all the thin layers are formed by plasma CVD. Compared with the formation of the film, the moisture and heat resistance of each thin layer can be improved, and the adhesion between the thin layers can be improved.
[0013]
In the invention according to claim 2, the thin layer formed by the plasma CVD method among the thin layers forming the laminate is a low refractive index layer or a medium refractive index layer, and is formed by a sputtering method or a vapor deposition method. It is characterized in that the formed thin layer is a high refractive index layer.
[0014]
According to the antireflection film of the present invention, of the thin layers forming the laminate, the thin layer formed by the plasma CVD method is a low refractive index layer or a medium refractive index layer, and is formed by a sputtering method or a vapor deposition method. Since the thin layer is a high refractive index layer, there is no particular problem even if it is formed by the plasma CVD method (that is, there is no problem in wet heat resistance). The formation rate can be increased by forming by the CVD method. On the other hand, when formed by the plasma CVD method, the refractive index may not be stable due to poor heat and humidity resistance. By forming by vapor deposition, the refractive index of the high refractive index layer can be stabilized.
[0015]
Furthermore, the invention according to claim 3 is the invention according to claim 2, wherein the low refractive index layer formed by the plasma CVD method has a refractive index of 1.40 to 1.46 (λ = 550 nm). Yes, 2800-3000cm^-1Absorption by C-H stretching vibration at 1,200 to 1400 cm^-1Si-CH at_ThreeInfrared absorption due to stretching vibration is 0.1cm each^-1It is characterized by the following silica layer.
[0016]
  According to this invention, since the refractive index of the silica layer used as the low refractive index layer of the laminate is 1.40 to 1.46 (λ = 550 nm), the silica layer has excellent adhesion and the formation speed is also high. fast. In addition, the silica layer is excellent in optical properties, can efficiently prevent light reflection, and can be used as a low refractive index layer in a laminate of antireflection films. 2800-3000cm^-1Absorption by C-H stretching vibration at 1,200 to 1400 cm^-1Si-CH at_ThreeInfrared absorption due to stretching vibration is 0.1cm each^-1Below, that is, below the detection sensitivity, it is clear that the organic layer is hardly contained in the silica layer, and as a result, it is excellent in chemical resistance while being a silica layer formed by the plasma CVD method. It is thought that there is. Since the low refractive index layer is often used as the outermost surface layer of the laminate, it may be dissolved in an alkaline solution when subjected to an alkali treatment after the production of the antireflection film, but according to the present invention, the aboveLow refractive index layerSince the silica layer is excellent in chemical resistance, it does not dissolve.
[0017]
Furthermore, the invention according to claim 4 is the invention according to claim 2 or claim 3, wherein the layer structure of the laminate is a medium refractive index layer formed by a plasma CVD method from the hard coat layer side, It is characterized by being a high refractive index layer formed by sputtering or vapor deposition and a low refractive index layer formed by plasma CVD.
[0018]
According to the antireflection film of the present invention, the layer structure of the laminate is from the hard coat layer side, a medium refractive index layer formed by a plasma CVD method, a high refractive index layer formed by a sputtering method or a vapor deposition method, Since it is a low refractive index layer formed by the plasma CVD method, reflection can be efficiently prevented by the layer structure, and a low refractive index layer and a middle refractive index layer are formed by the plasma CVD method, thereby achieving high refraction. Since the rate layer is formed by the sputtering method or the vapor deposition method, the same effects as those of the inventions described in the first and second aspects can be obtained.
[0019]
The invention according to claim 5 is the invention according to claim 2 or claim 3, wherein the layer structure of the laminate is formed from the hard coat layer side by a sputtering method or a vapor deposition method. And a low refractive index layer formed by a plasma CVD method, a high refractive index layer formed by a sputtering method or an evaporation method, and a low refractive index layer formed by a plasma CVD method.
[0020]
According to the antireflection film of the present invention, the layer structure of the laminate is a high refractive index layer formed by sputtering or vapor deposition from the hard coat layer side, a low refractive index layer formed by plasma CVD, Since it is a high refractive index layer formed by a sputtering method or a vapor deposition method, and a low refractive index layer formed by a plasma CVD method, reflection can be efficiently prevented by the layer configuration, and a low refractive index layer can be formed. Since it is formed by the plasma CVD method and the high refractive index layer is formed by the sputtering method or the vapor deposition method, the same effect as the invention described in the first and second aspects can be obtained.
[0021]
The invention according to claim 6 is the invention according to any one of claims 2 to 6, wherein the low refractive index layer or the middle refractive index layer formed by the plasma CVD method is a silicon oxide layer. The high refractive index layer formed by sputtering or vapor deposition is a titanium oxide layer or an ITO layer exhibiting high resistance.
[0022]
According to the antireflection film of the present invention, first, since the low refractive index layer or the middle refractive index layer formed by the plasma CVD method is a silicon oxide layer, the refractive index suitable for the low refractive index layer or the middle refractive index layer. It is possible to form a thin layer having a rate. In addition, since the high refractive index layer formed by sputtering or vapor deposition is a titanium oxide layer or an ITO layer exhibiting high resistance, a thin layer having a refractive index layer suitable for the high refractive index layer can be formed. Even when an ITO layer is used as a high refractive index layer, since the ITO layer has high resistance, a low refractive index layer can be formed on the ITO layer by plasma CVD. It is.
The invention according to claim 7 is a display device, characterized in that the antireflection film according to any one of claims 1 to 6 is used. The invention described in claim 8 is a liquid crystal display device, wherein the antireflection film according to any one of claims 1 to 6 is used.
[0023]
Embodiment
The antireflection film of the present invention will be specifically described below with reference to the drawings.
[0024]
FIG. 1 is a schematic cross-sectional view of the antireflection film of the present invention.
[0025]
As shown in FIG. 1, the antireflection film 1 of the present invention includes a base material 2, a hard coat layer 3 located on the base material 2, a hard coat layer 3, and a plurality of thin layers (5 to 5). 7) is formed from the laminated body 4 formed by laminating. The laminate 4 is characterized by being formed of a thin layer (5, 7) formed by a plasma CVD method and a thin layer (6) formed by a sputtering method or a vapor deposition method. Yes.
[0026]
As described above, not all of the thin layers forming the stacked body 4 are formed only by the plasma CVD method, or only by the sputtering method or the vapor deposition method, but depending on the thin layer to be formed, the plasma CVD method, the sputtering method, or By selectively using the vapor deposition method, the advantages of the plasma CVD method (thin layer formation speed is fast) and the advantages of the sputtering method and the vapor deposition method (when the thin layer has good adhesion and a high refractive index layer is formed). Even if the said layer has the heat-and-moisture resistance and a refractive index is stabilized, it can be combined, and it can be set as the antireflection film excellent in the antireflection function.
[0027]
Below, each of the thin layers (low refractive index layer 7, medium refractive index layer 5, high refractive index layer 6) constituting the base material 2, the hard coat layer 3, and the laminate 4 constituting the antireflection film 1 of the present invention. ) And the structure of the laminate 4 will be described.
[1] Base material
First, the substrate 2 will be described. In the antireflection film 1 of the present invention, the base material 2 is a portion that becomes a base of the antireflection film 1. The substrate 2 is not particularly limited as long as it is a polymer film that is transparent in the visible light region. Examples of the polymer film include triacetyl cellulose film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic film, polyurethane film, polyester film, polycarbonate film, polysulfone film, and polyether. Examples thereof include a film, a trimethylpentene film, a polyether ketone film, an acrylonitrile film, and a methacrylonitrile film. Furthermore, a colorless film can be used more preferably. Among them, a uniaxial or biaxially stretched polyester film is preferably used because it is excellent in transparency and heat resistance, and a polyethylene terephthalate (PET) film is particularly preferable. Triacetylcellulose is also preferably used in that it has no optical anisotropy. The thickness of the polymer film is preferably about 6 μm to 188 μm.
[2] Hard coat layer
Next, the hard coat layer 3 will be described. In the antireflection film 1 of the present invention, the hard coat layer 3 is a layer formed for the purpose of giving the antireflection film 1 strength.
[0028]
As a material for forming the hard coat layer 3 in the antireflection film 1 according to the present invention, it is a transparent material in the visible light region as in the case of the substrate 2, and the antireflection film 1 can be provided with strength. It is necessary to be a thing, and as the intensity | strength, it is preferable to show the height above H by the pencil height test shown by JISK5400.
[0029]
Specifically, it is preferable to use a thermosetting resin and / or an ionizing radiation type resin (these may be collectively referred to as a reaction curable resin in the present invention), and more specifically, an acrylate type. Polyfunctional compounds such as polyesters, polyethers, acrylic resins, epoxy resins, polyurethanes, alkyd resins, spiroacetal resins, polybutadienes, polythiol polyene resins, polyhydric alcohols, etc. (Meth) acrylate (hereinafter, acrylate and methacrylate are referred to as (meth) acrylate) and other oligomers or prepolymers and reactive diluents such as ethyl (meth) acrylate and ethylhexyl (meth) Acrylate, styrene, vinyl toluene, N-vinyl pyrrole Monofunctional monomers such as ethylene, and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri Those containing a relatively large amount of (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate and the like are used.
[0030]
Further, when the ionizing radiation curable resin is used as an ultraviolet curable resin, examples of the photopolymerization initiator include acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, thioxanthone. It is preferable to use n-butylamine, triethylamine, tri-n-butylphosphine or the like as a photosensitizer.
[0031]
The ionizing radiation curable resin includes a reactive organosilicon compound represented by the general formula RmSi (OR ′) n (wherein R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m + n = 4 And m and n are each integers). Examples of such silicon compounds include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert- Butoxysilane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltrimethoxysilane Ethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, di Chill propoxysilane, dimethyl-butoxy silane, methyl dimethoxy silane, methyl diethoxy silane, hexyl trimethoxy silane, and the like to.
[0032]
The layer thickness of such a hard coat layer 3 is usually in the range of 1 to 30 μm, and the production method thereof can use a normal coating method, and is not particularly limited.
[3] Laminate
The laminate 4 in the antireflection film 1 of the present invention is formed by laminating thin layers having different optical characteristics, and the entire laminate 4 depends on the optical properties (particularly the refractive index) and the layer configuration of each thin layer. It is configured to effectively prevent reflection.
[0033]
Usually, the thin layer which comprises the laminated body 4 is divided roughly into a low refractive index layer, a medium refractive index layer, and a high refractive index layer according to the refractive index. Here, in the present invention, the low refractive index layer, the middle refractive index layer, and the high refractive index layer are, in the case where the thin layers constituting the laminate 4 are relatively compared with each other by the respective refractive indexes, It is a name for distinguishing each thin layer, a layer having a relatively high refractive index is a high refractive index layer, a layer having a relatively low refractive index is a low refractive index layer, and the high refractive index layer and the low refractive index layer. A layer having an intermediate refractive index is defined as a middle refractive index layer. In general, the refractive index is often 1.80 or more as a high refractive index layer, 1.55 or more and less than 1.80 as a medium refractive index layer, and less than 1.55 as a low refractive index layer. The refractive index is 1.80 or more as a high refractive index layer, 1.55 or more and less than 1.80 as a medium refractive index layer, and less than 1.55 as a low refractive index layer.
[0034]
Below, each thin layer is demonstrated concretely.
[0035]
(3-1) Low refractive index layer
In the antireflection film 1 of the present invention, the low refractive index layer (7) is one of the thin layers forming the laminate 3, and its refractive index is less than 1.55 (λ = 550 nm). It is a thin layer. Thus, by using a layer having a relatively low refractive index as a thin layer in the stacked body 4, it is possible to efficiently prevent reflection as the entire stacked body 4. In the antireflection film 1 of the present invention, the position of the low refractive index layer (7) in the laminate 4 is not particularly limited, but the normal low refractive index layer (7) is shown in FIG. Thus, it is preferable to use for the outermost layer (opposite side of the hard-coat layer 3) of the laminated body 4.
[0036]
In the present invention, the thin layer that can be used as the low refractive index layer (7) is particularly limited as long as it is transparent and has a refractive index of less than 1.55 (λ = 550 nm). However, in the present invention, a thin layer that can be formed by a plasma CVD method is particularly preferable.
[0037]
Specific examples of such a low refractive index layer (7) include a silicon oxide layer, a magnesium fluoride layer, a silicon oxyfluoride layer, and the like. It is preferable to use it as a layer.
[0038]
The silicon oxide layer is relatively easy to have a refractive index of less than 1.55 (λ = 550 nm), and even if it is formed by plasma CVD, it is a thin film with excellent heat and moisture resistance and a stable refractive index. This is because a layer can be obtained, and the plasma CVD method has a high formation rate of a thin layer. Note that the composition of the silicon oxide layer does not need to be simply SiOx, and may be a silicon oxide layer (SiOxCy) containing carbon. This is because, by containing carbon in the silicon oxide layer, the refractive index of the silicon oxide layer can be more easily set to a desired refractive index.
[0039]
The layer thickness of such a low refractive index layer is not particularly limited, but is preferably 10 to 1000 nm, and particularly preferably in the range of 50 to 150 nm. If the layer thickness is thinner than the above range, the antireflection effect may not be achieved, and if the layer thickness is thicker than the above range, the entire layer may become brittle and may lack moldability. .
[0040]
Here, the plasma CVD method used when forming the low refractive index layer (7) in the antireflection film 1 of the present invention will be specifically described.
[0041]
In the present invention, the plasma CVD method means that an atomic or molecular radical species is generated by plasma generation in a reaction chamber into which a predetermined gas is introduced and adheres to a solid surface. It is a stratification method that utilizes the phenomenon that is released into the solid surface. By forming the antireflection film of the present invention using the plasma CVD method, a plurality of layers can be efficiently formed at once. In addition, the plasma CVD method includes two types, that is, a capacitively coupled plasma CVD method and an inductively coupled plasma CVD method depending on a method of applying electric power used to generate plasma. Either plasma CVD method can be used.
[0042]
Here, in the present invention, among the plasma CVD methods as described above, it is particularly preferable to use a plasma CVD apparatus as shown in FIG. This is because the antireflection film of the present invention can be continuously produced by the plasma CVD apparatus, and the temperature control of the polymer film as the substrate can be accurately performed.
[0043]
A plasma CVD apparatus 20 shown in FIG. 2 is a capacitively coupled plasma CVD apparatus, and a web-like polymer film 21 is unwound from a substrate unwinding section 22 to be reacted in a reaction chamber (a, b, c). Then, a predetermined layer is formed on the stratification drum 24 in the reaction chamber, and is wound up by the substrate winding unit 26.
[0044]
The plasma CVD apparatus 20 is characterized in that it has a plurality (three) of reaction chambers, and each reaction chamber (a, b, c) is formed by being isolated by an isolation wall 25. ing. Here, for convenience of the following description, the three reaction chambers are referred to as a reaction chamber a, a reaction chamber b, and a reaction chamber c from the right side. In each reaction chamber, electrode plates a1, b1, c1 and source gas inlets a2, b2, c2 are installed, respectively. Each reaction chamber (a, b, c) is installed along the outer periphery of the stratification drum 24. This is because the polymer film on which the antireflection laminate is formed is inserted into the reaction chamber in synchronization with the stratification drum 24 and forms the antireflection laminate on the stratification drum. It is because each layer can be laminated | stacked continuously by arrange | positioning in this way.
[0045]
According to the plasma CVD apparatus as described above, it is possible to form layers independently in each reaction chamber by changing the source gas introduced into each reaction chamber.
[0046]
In the present invention, when the silicon oxide layer as the low refractive index layer (7) is formed using the plasma CVD apparatus (for example, the reaction chamber a) as described above, it is preferable to use organic silicone as the source gas. Specifically, hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), methyltrimethoxysilane (MTMOS), methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, tetramethoxysilane, octa Methylcyclotetrasiloxane, octamethylcyclotetrasiloxane, tetraethoxysilane, or the like can be used.
[0047]
In the present invention, among the low refractive index layers formed by the plasma CVD method as described above, the refractive index is 1.40 to 1.46 (λ = 550 nm) and 2800 to 3000 cm.^-1Absorption by C-H stretching vibration at 1,200 to 1400 cm^-1Si-CH at_ThreeInfrared absorption due to stretching vibration is 0.1cm each^-1The following silica layer is preferably used as the low refractive index layer.
[0048]
In the antireflection film, the smaller the refractive index of the low refractive index layer in the laminate, the better. If the refractive index is within this range, it is suitable as the low refractive index layer.
[0049]
The silica layer is 2800 to 3000 cm.^-1Absorption by C-H stretching vibration at 1,200 to 1400 cm^-1Si-CH at_ThreeInfrared absorption by stretching vibration is 0.1cm^-1It is characterized by the following, that is, below the detection sensitivity.
[0050]
2800-3000cm^-1Absorption by C-H stretching vibration at 1,200 to 1400 cm^-1Si-CH at_ThreeInfrared absorption by stretching vibration is 0.1cm^-1The following means that there are almost no C—H bonds or Si—CH 3 bonds in the silica layer. That is, it is considered that the silica layer of the present invention does not contain a carbon compound (organic substance), and therefore, it is considered that the chemical resistance is excellent.
[0051]
Here, the absorption of infrared rays is measured by a known IR spectrum transmission method, and the value of ∫ (α / f) df in infrared absorption of each stretching vibration is calculated (α: absorption coefficient, f: frequency).
[0052]
(3-2) Medium refractive index layer
Next, the middle refractive index layer will be described.
[0053]
In the antireflection film 1 of the present invention, the middle refractive index layer (5) is one of the thin layers forming the laminate 3, and has a refractive index of 1.55 or more and less than 1.80. Is a layer. The medium refractive index layer (5) having such a refractive index is a thin layer used for enhancing the antireflection function, and is not necessarily a necessary thin layer in the laminate 4. The position where the intermediate refractive index layer is provided is not particularly limited, and any position can be used as long as the antireflection function is improved as a whole of the laminate 4. However, since the low refractive index layer (7) and the high refractive index layer (6) are in contact with each other, light reflection can be efficiently prevented (see FIG. 1). (5) is preferably provided at a portion other than between the low refractive index layer and the high refractive index layer, for example, below the high refractive index layer as shown in FIG.
[0054]
In the present invention, the thin layer that can be used as the middle refractive index layer (5) has transparency in the visible light region, and has a refractive index of 1.55 or more and less than 1.80 (λ = 550 nm). Although it is not particularly limited as long as it is a certain thin layer, in the present invention, it is particularly preferable that it is a thin layer that can be formed by a plasma CVD method as in the case of the low refractive index layer.
[0055]
Examples of such a medium refractive index layer (5) include a carbon-containing silicon oxide layer and Al.₂O_Three, SiN, SiON, ZrO₂, SiO₂ZnO₂The fine particles dispersed in the silicon oxide layer are preferably used. By mixing the fine particles in the silicon oxide layer, it is relatively easy to set the refractive index to 1.55 or more and less than 1.80 (λ = 550 nm). The silicon oxide layer is formed by a plasma CVD method. This is because a thin layer having excellent moisture and heat resistance and a stable refractive index can be obtained. Since the plasma CVD method has a high formation rate of a thin layer, the yield of manufacturing an antireflection film can be improved.
[0056]
The thickness of such a medium refractive index layer is not particularly limited, but is preferably 5 to 300 nm, and particularly preferably 10 to 150 nm. If the layer thickness is less than 5 nm, the antireflection effect can hardly be expected. Conversely, if the layer thickness is more than 300 nm, the base material may be deformed or peeled off due to the layer stress. Because.
[0057]
Here, since the plasma CVD method used when forming the middle refractive index layer (5) in the antireflection film 1 of the present invention is the same as that in the case of the low refractive index layer (7), the description thereof is omitted. . In the case where the plasma CVD apparatus shown in FIG. 2 is used, for example, the reaction chamber b is used to form the intermediate refractive index layer (5). Different (different refractive indices) thin layers can be formed.
[0058]
(3-3) High refractive index layer
Next, the high refractive index layer will be described.
[0059]
In the antireflection film 1 of the present invention, the high refractive index layer (6) is one of the thin layers forming the laminate 3, and has a refractive index of 1.80 or more (λ = 550 nm). Is a layer. In combination with the low refractive index layer described above, a thin layer having a refractive index of 1.80 or more (λ = 550 nm) is provided in the laminated body 4 to efficiently prevent light reflection due to the difference in refractive index. be able to. In the antireflection film 1 of the present invention, the position occupied by the high refractive index layer (6) in the laminate 4 is not particularly limited. However, as described above, the low refractive index layer (7) and the high refractive index layer are highly refractive. Since it is possible to efficiently prevent reflection of light when they are in contact with the refractive index layer (6), it is preferably provided under the low refractive index layer.
[0060]
In the present invention, the thin layer that can be used as the high refractive index layer (6) is a thin layer having transparency in the visible light region and a refractive index of 1.80 or more (λ = 550 nm). Although there is no particular limitation as long as it is present, a thin layer formed by sputtering or vapor deposition is particularly preferred in the present invention. Thus, by forming the high refractive index layer (6) by sputtering or vapor deposition, the formation speed is inferior to that by the plasma CVD method, but it has excellent resistance to moist heat and therefore stable refractive index. This is because a high refractive index layer having excellent adhesion to other thin layers can be obtained.
[0061]
As such a high refractive index layer (7), specifically, a titanium oxide layer, an ITO (indium / tin oxide) layer, Y₂O_ThreeLayer, In₂O_ThreeLayer, Si_ThreeN_FourLayer, SnO₂Layer, ZrO₂Layer, HfO₂Layer, Sb₂O_ThreeLayer, Ta₂O_FiveLayer, ZnO layer, WO_ThreeAmong them, a titanium oxide layer or an ITO layer exhibiting high resistance is particularly preferably used as the high refractive index layer.
[0062]
Conventionally, a titanium oxide layer has been used as a high refractive index layer of a laminate in an antireflection film, but the titanium oxide layer was formed by a plasma CVD method in the same manner as the low refractive index layer and the medium refractive index layer described above. In this case, since the formed titanium oxide layer has poor heat and heat resistance, there has been a problem that the refractive index changes due to moisture in the air. Since this titanium oxide layer is formed by sputtering or vapor deposition, such a problem does not occur. Further, by forming by sputtering or vapor deposition, adhesion to other thin layers (low refractive index layer or medium refractive index layer) or hard coat layer can also be improved.
[0063]
In addition, since the ITO layer usually has conductivity, it is difficult to form a thin layer by plasma CVD on the ITO layer formed by sputtering or vapor deposition. Since the ITO layer used as the rate layer is an ITO layer exhibiting high resistance, it is possible to form a thin layer thereon by plasma CVD. As described above, the ITO layer used as the high refractive index layer in the present invention exhibits a high resistance when the ITO layer is formed under oxygen-excess conditions when the ITO layer is formed by sputtering or vapor deposition. This is because the oxygen filling rate of the layer is increased. Here, in the present invention, “high resistance” means that the sheet resistance is 1 × 10.^Four~ 1x10¹⁴Say Ω / sq.
[0064]
The layer thickness of such a high refractive index layer is not particularly limited, but is preferably 5 to 300 nm, and particularly preferably 10 to 150 nm. If the layer thickness is less than 5 nm, the antireflection effect can hardly be expected. Conversely, if the layer thickness is more than 300 nm, the base material may be deformed or peeled off due to the layer stress. Because.
[0065]
Here, the sputtering method and vapor deposition method used when forming the high refractive index layer (6) in the antireflection film 1 of the present invention will be specifically described.
[0066]
In the present invention, the sputtering method means that high-energy particles are struck against a solid, which is a thin base material called a target, and the constituent atoms of the base material are released from the surface of the solid. In this method, a thin layer is formed by deposition. A method of depositing a thin layer by repelling atoms from the surface by accelerating a cation generated by glow discharge of an inert gas such as argon with a cathode fall voltage and colliding with a negatively biased target. It is common.
[0067]
As the sputtering method used for forming the high refractive index layer (6) in the antireflection film 1 of the present invention, all of the conventionally used sputtering methods can be used. A sputtering method, a high frequency sputtering method, a direct current sputtering method, an ECR sputtering method, a magnetron sputtering method, a reactive sputtering method, or the like can be used, and is not particularly limited.
[0068]
FIG. 3 is a schematic view of a DC sputtering apparatus for performing DC sputtering among the various sputtering methods. In the present invention, it is possible to form a high refractive index layer using such an apparatus.
[0069]
In the DC sputtering apparatus 30 shown in FIG. 3, a web-shaped polymer film 31 as a base material is unwound from the base material unwinding portion 32 and introduced into the reaction chamber 33. Then, a predetermined layer is formed on the stratification drum 34 in the reaction chamber 33 and is taken up by the substrate take-up unit 36.
[0070]
In the reaction chamber 33 of the DC sputtering apparatus 30, a target 35 is placed against the stratification drum 34, and the stratification drum 34 is an anode and the target 35 is a cathode. The inside of the reaction chamber 33 is in a vacuum state (10^-3Then, an inert gas such as argon or oxygen gas is added at 1 to 10 Pa. By applying a DC high voltage between the stratification drum 34 and the target 35, positive ions collide with the cathode (target 35), whereby the target is repelled and deposited on the polymer resin on the stratification drum 34. .
[0071]
In the present invention, when the titanium oxide layer as the high refractive index layer (6) is formed by sputtering, the target is Ti, Ti₂O_ThreeTiO₂It is preferable to use TiO. Moreover, when forming the ITO layer as a high refractive index layer (6), it is preferable to use ITO or an indium / tin alloy as a target.
[0072]
In the present invention, the vapor deposition method mainly means 10^-6-10^-11This is a method for forming a thin layer by superheating a solid in a Torr vacuum and cooling and condensing the vapor on a substrate maintained at a constant temperature. In the present invention, all of the conventionally used vapor deposition methods can be used and are not particularly limited. In the vapor deposition method, when the titanium oxide layer as the high refractive index layer (6) is formed, the raw materials thereof are Ti, Ti₂O_ThreeTiO₂It is preferable to use TiO. Moreover, when forming the ITO layer as a high refractive index layer (6), it is preferable to use ITO or an indium / tin alloy as a raw material.
[0073]
Thus, in the antireflection film 1 of the present invention, each thin layer constituting the laminate 4 is not formed only by the plasma CVD method or the sputtering method, but specifically, according to each thin layer, The low refractive index layer and the middle refractive index layer use a plasma CVD method in which the formation speed of the thin layer is high, and the high refractive index layer can form a thin layer having excellent heat and moisture resistance and a stable refractive index. By using an appropriate sputtering method or vapor deposition method, it is possible to provide an antireflection film having a good yield and an excellent antireflection function when producing the antireflection film.
[0074]
(3-4) Layer structure
Next, the layer structure of the laminate 4 in the antireflection film 1 of the present invention will be specifically described with reference to the drawings.
[0075]
In the antireflection film 1 of the present invention, the layer structure of the laminate 4 is not particularly limited. The layer structure is formed by a thin layer formed by a plasma CVD method and a sputtering method or a vapor deposition method. The thin layer is included, and it is only necessary that the entire laminate can exhibit the antireflection function.
[0076]
However, as shown in FIG. 1, the laminated body 4 includes, from the hard coat layer 3 side, a medium refractive index layer 5 formed by a plasma CVD method, a high refractive index layer 6 formed by a sputtering method or an evaporation method, It is preferable that the low refractive index layers 7 formed by the plasma CVD method are stacked in this order. By laminating in this way, reflection of light can be effectively prevented from the difference in refractive index of each thin layer, and the high refractive index layer 6 is formed by sputtering or vapor deposition, This is because it is excellent in wet heat resistance and has good adhesion to the middle refractive index layer 5 that is the lower layer of the high refractive index layer 6 and the low refractive index layer 7 that is the upper layer.
[0077]
A laminate 4 'as shown in FIG. 4 is also preferable as the antireflection film of the present invention. As shown in FIG. 4, a high refractive index layer 6 ′ formed by sputtering or vapor deposition and a low refractive index layer 7 ′ formed by plasma CVD are alternately laminated twice from the hard coat layer 3 side. This is because the antireflection effect can be improved.
[0078]
In addition, this invention is not limited to the antireflection film and its manufacturing method which have been mentioned above. The above-described embodiment is an exemplification, and any structure that has substantially the same configuration as the technical scope described in the claims of the present invention and has the same operational effects can be used. It is included in the technical scope of the present invention.
The antireflection film of the present invention can be suitably used for a display device, for example, a liquid crystal display device.
[0079]
【Example】
The present invention will be described in more detail with reference to examples.
(Example 1)
Using the sputtering apparatus shown in FIG. 3, an ITO layer was formed on a 75 μm thick polyethylene terephthalate (PET) film, which is a plastic film as a base material. The feed rate of the base polymer film during continuous stratification in this example was 0.1 m / min. Other conditions are as follows.
<Stratification conditions>
Applied power 1.0 kW
Oxygen gas flow rate 27sccm
Drum surface temperature (stratification temperature) 30 ℃
The gas flow unit sccm is a standard cubic cm permit.
[0080]
The measurement results of the ITO layer formed on the polyethylene terephthalate film under the above conditions are shown below.
[0081]
<ITO layer measurement result>
Layer thickness 55nm
Layering speed 5.5nm ・ m / min
Refractive index (λ = 550 nm) 2.0
Sheet resistance 10¹¹Ω / sq
<Apparatus used for ITO layer measurement>
Layer thickness measurement: Ellipsometer (model number: UVISELTM, manufacturer: JOBINYVON)
Sheet resistance measurement: MCP-HT450 (Manufacturer: Mitsubishi Chemical Corporation)
Refractive index measurement: Ellipsometer (model number: UVISELTM, manufacturer: JOBIN YVON)
As shown in the above ITO layer formation results, a homogeneous and highly insulating titanium oxide layer having a refractive index of 2.0 is formed on a polyethylene terephthalate film at a deposition rate of 5.5 nm · m / min at a deposition temperature of 30 ° C. Was able to be formed. Further, this ITO layer was a highly transparent thin layer having an extinction coefficient of 0.003 at λ = 550 nm from an ellipsometer measurement result. In addition, the polyethylene terephthalate film after formation of the ITO layer was in a good state with little elongation and no deformation.
(Example 2)
Using the sputtering apparatus shown in FIG. 3, an ITO layer was formed on a 75 μm thick polyethylene terephthalate (PET) film, which is a plastic film as a base material. The feed rate of the base polymer film during continuous stratification in this example was 0.1 m / min. Other conditions are as follows.
<Stratification conditions>
Applied power 1.0 kW
Oxygen gas flow rate 90sccm
Drum surface temperature (stratification temperature) 30 ℃
The measurement results of the ITO layer formed on the polyethylene terephthalate film under the above conditions are shown below.
[0082]
<ITO layer measurement result>
Layer thickness 14nm
Layering speed 1.4nm ・ m / min
Refractive index (λ = 550 nm) 2.0
Sheet resistance 10¹¹Ω / sq or more
<Apparatus used for ITO layer measurement>
Layer thickness measurement: Ellipsometer (model number: UVISELTM, manufacturer: JOBINYVON)
Sheet resistance measurement: MCP-HT450 (Manufacturer: Mitsubishi Chemical Corporation)
Refractive index measurement: Ellipsometer (model number: UVISELTM, manufacturer: JOBIN YVON)
As shown in the above ITO layer formation results, at a stratification temperature of 30 ° C., a homogeneous and highly insulating titanium oxide layer having a refractive index of 2.0 is formed on a polyethylene terephthalate film at a stratification rate of 1.4 nm · m / min. Was able to be formed. Further, this ITO layer was a highly transparent thin layer having an extinction coefficient of 0.003 at λ = 550 nm from an ellipsometer measurement result. In addition, the polyethylene terephthalate film after formation of the ITO layer was in a good state with little elongation and no deformation.
[0083]
From the above Examples 1 and 2, it became clear that a thin layer (ITO layer) suitable for the laminate in the antireflection film can be formed on the base material using the sputtering method.
(Example 3)
As shown in FIG. 1, a hard coat layer 3, a medium refractive index layer 5 formed by a plasma CVD method, a high refractive index layer 6 formed by a sputtering method, and a plasma CVD method are formed on a polymer film 2 as a substrate. The laminated body 4 composed of the low refractive index layer 7 was formed to produce an antireflection film. The conditions for forming each layer are described below.
<Polymer film (2)>
Triacetylcellulose thickness 80μm
<Hard coat layer (3)>
UV curable resin PET-D31 (Daiichi Seika Kogyo Co., Ltd.)
Formed by coating
UV curing condition 480mJ
Thickness 6μm
<Medium refractive index layer (5)>
A carbon-containing silicon oxide layer was formed by the plasma CVD apparatus shown in FIG.
<High refractive index layer (6)>
The same ITO layer as in Example 1 was formed under the same conditions.
<Low refractive index layer (7)>
A silicon oxide layer was formed by the plasma CVD apparatus shown in FIG.
[0084]
The antireflection film formed under the above conditions was in a good state with no slight elongation or deformation of the polymer film. The reflection spectral characteristics of the antireflection film prepared under the above conditions are shown in FIG. From FIG. 5, the reflectance near 550 nm, which is easy for humans to sense, was low, and the antireflection effect was good. The visibility reflectance at this time was a good value of 0.3%.
[0085]
Spectral reflectance was measured with the following apparatus.
Spectral reflectance measurement: spectrophotometer (model number: UV-3100PC, manufacturer: Shimadzu Corporation)
Note that the film thickness of the laminated film formed in the above example was set so that the visibility reflectance was minimized in consideration of the optical characteristics of each layer. For example, in the medium refractive index layer, the high refractive index layer, and the low refractive index layer shown in Example 2, when forming each thin layer using each device for forming the desired layer, the film feeding speed is adjusted to adjust the film thickness. The film thickness is obtained.
[0086]
【The invention's effect】
According to the antireflection film of the present invention, the laminate constituting the antireflection film of the present invention is formed by laminating a thin layer formed by a plasma CVD method and a thin layer formed by a sputtering method or a vapor deposition method. Therefore, the formation speed can be increased compared to the case where all the thin layers forming the laminate are formed by sputtering or vapor deposition, while all the thin layers are formed by plasma CVD. Compared with the formation, adhesion between the thin layers can be improved.
[0087]
Further, among the thin layers forming the laminate, the thin layer formed by the plasma CVD method is a low refractive index layer or the middle refractive index layer, and the thin layer formed by the sputtering method or the vapor deposition method is a high refractive index layer. Therefore, a low refractive index layer or a middle refractive index layer that does not cause any particular problems even if formed by the plasma CVD method (does not cause a problem in the resistance to moist heat) is formed by the plasma CVD method to increase the formation speed. On the other hand, when formed by the plasma CVD method, the refractive index may not be stable due to poor moisture and heat resistance. Only the high refractive index layer is formed by the sputtering method or the vapor deposition method. The refractive index of the refractive index layer can be stabilized.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of an antireflection film of the present invention.
FIG. 2 is a schematic view of a plasma CVD apparatus.
FIG. 3 is a schematic view of a sputtering apparatus.
FIG. 4 is a schematic cross-sectional view showing an example of the antireflection film of the present invention.
5 is a graph showing the reflection spectral characteristics of the antireflection film of Example 3. FIG.
[Explanation of symbols]
1, 1 '... Antireflection film
2, 2 '... substrate
3, 3 '... hard coat layer
4, 4 '... laminate
5 ... Middle refractive index layer
6, 6 '... high refractive index layer
7, 7 '... low refractive index layer
20 ... Plasma CVD apparatus
30 ... DC sputtering equipment

Claims (6)

In an antireflection film having a base material, a hard coat layer located on the base material, and a laminate formed by laminating a plurality of thin layers located on the hard coat layer,
Of the thin layers forming the laminate, the thin layer formed by plasma CVD is a low refractive index layer or medium refractive index layer made of silicon oxide , and the thin layer formed by sputtering or vapor deposition is used. An antireflection film, which is a high refractive index layer made of ITO having a sheet resistance of 1 × 10 ⁴ to 1 × 10 ¹⁴ Ω / sq . The low refractive index layer formed by the plasma CVD method has a refractive index of 1.40 to 1.46 (λ = 550 nm) and infrared absorption by C—H stretching vibration at 2800 to 3000 cm ⁻¹ . the antireflection film according to claim 1 and infrared absorption by Si-CH ₃ stretching vibration at 1200～1400Cm ^-1, characterized in 0.1 cm ^-1 or less of the silica layer, respectively.   The layer structure of the laminate is, from the hard coat layer side, a medium refractive index layer formed by plasma CVD, a high refractive index layer formed by sputtering or vapor deposition, and a low refractive index formed by plasma CVD. The antireflection film according to claim 1, wherein the antireflection film is a layer.   The layer structure of the laminate is, from the hard coat layer side, a high refractive index layer formed by a sputtering method or a vapor deposition method, a low refractive index layer formed by a plasma CVD method, a high refractive layer formed by a sputtering method or a vapor deposition method. The antireflective film according to claim 1, wherein the antireflective film is a refractive index layer or a low refractive index layer formed by a plasma CVD method. A display device, wherein the antireflection film according to any one of claims 1 to 4 is used.   A liquid crystal display device, wherein the antireflection film according to any one of claims 1 to 4 is used.

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