JP3732451B2 - Method for producing transparent laminated film, transparent laminated film and antireflection film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a transparent laminated film in which a silicon oxide layer is formed on a substrate made of a plastic film by a plasma CVD method, and a transparent laminated film obtained by the production method. The present invention relates to an antireflection film provided with a film.
[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]
On the other hand, at present, in order to solve the above-described drawbacks, 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 provided. It has been practiced to prevent reflection of light by using the antireflection film on the surface of the transparent substrate. A typical configuration of the antireflection film is an indium tin oxide (indium doped with tin) for preventing static electricity on a transparent substrate film.₂O_ThreeA thin film having a lower refractive index than that of the transparent conductive thin film, for example, SiO, for preventing reflection.₂The thing which formed the thin film of this is mentioned.
[0004]
[Problems to be solved by the invention]
When a silicon oxide layer (silica layer) is formed as a thin film on a plastic film, it is possible to dramatically improve the film formation speed by using the plasma CVD method compared to the sputtering method. , Productivity has increased.
However, in the above plasma CVD method, when a silicon oxide layer is formed on a substrate in a reaction chamber, the source gas (silicon compound) and oxygen are combined to form a silicon oxide thin film, which is why There is a problem that a uniform thin film cannot be obtained and the refractive index is not stable.
[0005]
Therefore, in order to solve the above-mentioned problems, the present invention is uniform by preventing the silicon oxide layer from being formed into fine particles when the silicon oxide layer is formed on the substrate made of a plastic film by the plasma CVD method. , Method for producing transparent laminated film capable of forming silicon oxide thin film having stable refractive index, and transparent laminated film obtained therebyAnd antireflection filmIs intended to provide.
[0006]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the method for producing a transparent laminated film of the present invention is the transparent laminated film according to claim 1, wherein a transparent oxide thin film is formed on a substrate made of a plastic film by a plasma CVD method. In the manufacturing method, in the reaction chamber in the plasma CVD methodSilicon compound gasOxygen gas, inert gas, and the oxygen gasSilicon compound gasFlow rate ratio (oxygen gas /Silicon compound gas) Is 0.5 to 10, and the flow rate ratio of inert gas to oxygen gas (inert gas / oxygen gas) is 0.05 to 0.7,Silicon compound gasMean free path of the gas molecules of the whole gas mixed with (λ = kT / πpd²√2) under the condition of 0.7 cm to 5 cm,Silicon oxide layerOn the substrate,Silicon oxide layerThe refractive index is 1.4 to 1.55 (wavelength λ = 550 nm), and the surface roughness Ra is 3 nm or more and 30 nm or less. According to a second aspect of the present invention, the transparent laminated film of the present invention is characterized in that a transparent oxide thin film is provided on a plastic film substrate by the method for producing a transparent laminated film according to the first aspect.
[0007]
As a third aspect, a silicon oxide layer having a refractive index of 1.55 to 1.8 (wavelength λ = 550 nm) and a film thickness of 10 to 200 nm on a substrate, a refractive index of 1.8 or more (wavelength λ = 550 nm) The high-refractive index layer and the oxide thin film according to claim 2 are laminated in this order.
The oxide thin film according to claim 2, wherein the oxide thin film has a high refractive index layer, a refractive index of 1.4 to 1.55 (wavelength λ = 550 nm), and a film thickness of 10 to 200 nm on the substrate. The high refractive index layer, the oxide thin film, the high refractive index layer, and the oxide thin film are laminated in this order on the base material.
[0008]
As a fifth aspect, a hard coat layer is formed between the base material according to any one of the second to fourth aspects and a layer provided on the base material, that is, an antireflection film. Features.
According to a sixth aspect of the present invention, an antifouling layer is formed on the outermost surface of the antireflection film of the transparent laminated film according to any one of the first to fifth aspects.
Furthermore, as a seventh aspect, the substrate according to any one of the first to sixth aspects is a uniaxial or biaxially stretched polyester film or a triacetyl cellulose film.
The antireflection film of the present invention is characterized in that, as claim 8, the transparent laminated film described in any one of claims 1 to 7 is an antireflection film.
[0009]
  The transparent laminated film obtained by the above production method is
When a transparent oxide thin film is formed by plasma CVD on a substrate made of plastic film, the reaction chamber in plasma CVD is used.Silicon compound gasOxygen gas, inert gas, and the oxygen gasSilicon compound gasFlow rate ratio (oxygen gas /Silicon compound gas) Is 0.5 to 10, and the flow rate ratio of inert gas to oxygen gas (inert gas / oxygen gas) is 0.05 to 0.7,Silicon compound gasMean free path of the gas molecules of the whole gas mixed with (λ = kT / πpd²√2) If the condition is 0.7 cm or more and 5 cm or less, the inert gas isSilicon compound gasImproves the uniformity of the gas mixture in the reaction of oxygen with oxygen gas, resulting in a stable discharge voltage and a thin oxide filmIs a silicon oxide layerCan be prevented from becoming fine particles. This makes it possible to form an oxide thin film that is uniform and has a stable low refractive index on a substrate, and is laminated with a high refractive index layer to provide a transparent laminate with an antireflection function that sufficiently reduces external light reflection. A film, that is, an antireflection film can be produced while maintaining stable quality.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
FIG. 1 shows one embodiment which is a transparent laminated film 1 of the present invention. On a substrate 2 made of a plastic film, the refractive index is 1.4 to 1.55 (wavelength λ = 550 nm), the surface roughness. A transparent oxide thin film 3 having Ra of 3 nm or more and 30 nm or less is provided. This oxide thin film 3 is a low refractive index layer.
Moreover, FIG. 2 shows other embodiment which is the transparent laminated film 1 of this invention, and refractive index is 1.55-1.8 (wavelength (lambda) = 550nm) and film thickness on the base material 2 which consists of a plastic film. Silicon oxide layer 4 having a thickness of 10 to 200 nm, high refractive index layer 5 having a refractive index of 1.8 or more (wavelength λ = 550 nm), refractive index of 1.4 to 1.55 (wavelength λ = 550 nm), surface roughness An oxide thin film 3 having a thickness Ra of 3 nm or more and 30 nm or less is laminated in this order. The silicon oxide layer 4 is a medium refractive index layer.
In FIG. 1, the transparent laminated film 6 including only the oxide thin film 3 is formed on the substrate 2, but in FIG. 2, the silicon oxide layer 4, the high refractive index layer 5, and the oxide thin film are formed on the substrate 2. A transparent laminated film 6 made of 3 is provided.
[0011]
  The low refractive index layer, the medium refractive index layer, and the high refractive index layer are named by distinguishing them from the difference in relative refractive index in the thin film constituting the transparent laminated film. In the present invention, the low refractive index layer is a layer having a relatively low refractive index,Less than 1.55The refractive index is The high refractive index layer is a relatively high layer and has a refractive index of 1.8 or more. The medium refractive index layer has an intermediate refractive index between the low refractive index layer and the high refractive index layer, and has a refractive index of 1.55 or more and less than 1.8. However, all the refractive indexes of the present invention are measured with light having a wavelength of 550 nm. Moreover, FIG. 3 shows other embodiment which is the transparent laminated film 1 of this invention, on the base material 2 which consists of a plastic film, the high refractive index layer 5, refractive index is 1.4-1.55 (wavelength (lambda)). = 550 nm) and an oxide thin film 3 having a film thickness of 10 to 200 nm are laminated in this order, and a transparent laminated film (antireflection film) 6 comprising a high refractive index layer 5 and an oxide thin film 3 on a substrate 2. Is provided.
[0012]
FIG. 4 shows another embodiment which is the transparent laminated film 1 of the present invention, and a high refractive index layer 5, an oxide thin film 3, a high refractive index layer 5, and an oxide thin film on a substrate 2 made of a plastic film. 3, the unit of the high refractive index layer 5 and the oxide thin film 3 is repeatedly formed twice. In this case, a transparent laminated film (antireflection film) 6 comprising four layers of a high refractive index layer 5, an oxide thin film 3, a high refractive index layer 5, and an oxide thin film 3 is provided on the substrate 2.
[0013]
FIG. 5 shows another embodiment of the transparent laminated film 1 according to the present invention, in which a hard coat layer 7, a high refractive index layer 5, and an oxide thin film 3 are sequentially formed on a substrate 2 made of a plastic film. In other words, it is the transparent laminated film 1 in which the antireflective film 6 composed of the high refractive index layer 5 and the oxide thin film 3 is provided on the base material 2 via the hard coat layer 7.
FIG. 6 shows another embodiment which is the transparent laminated film 1 of the present invention. A silicon oxide layer 4, a high refractive index layer 5, an oxide thin film 3, and an antifouling layer 8 are formed on a substrate 2 made of a plastic film. The antireflection film 6 and the antifouling layer 8 comprising the silicon oxide layer 4, the high refractive index layer 5, and the oxide thin film 3 are sequentially provided on the substrate 2.
[0014]
First, each layer which comprises the transparent laminated film of this invention is demonstrated.
(Base material)
As the substrate 2 of the transparent laminated film of the present invention, a plastic film is used and transparency is required. For example, a triacetyl cellulose film, a diacetyl cellulose film, an acetate butyrate cellulose film, a polyether sulfone film, a poly Examples include acrylic films, polyurethane films, polyester films, polycarbonate films, polysulfone films, polyether films, trimethylpentene films, polyetherketone films, acrylonitrile films, and methacrylonitrile films. Furthermore, a colorless and transparent film can be used more preferably. Among them, a uniaxial or biaxially stretched polyester film is excellent in transparency and heat resistance and is preferably used, and triacetyl cellulose is also preferably used in terms of no optical anisotropy. A plastic film having a thickness of about 6 μm to 188 μm is preferably used.
[0015]
(Oxide thin film)
In the transparent laminated film of the present invention, a transparent oxide thin film 3 is provided on a substrate made of a plastic film by a plasma CVD method, and this oxide thin film has a refractive index of 1.4 to 1.55 ( Wavelength λ = 550 nm) and surface roughness Ra is 3 nm or more and 30 nm or less. Therefore, this oxide thin film is a low refractive index layer, and suppresses the point that the raw material gas (silicon compound) and oxygen are combined when forming a film by the plasma CVD method, and the oxide thin film tends to be finely divided, Formed. The raw material gas for forming the silica film in the present invention includes silane, disilane, hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), methyltrimethoxysilane (MTMOS), methylsilane, dimethylsilane, and trimethylsilane. Si-based compounds such as diethylsilane, propylsilane, phenylsilane, tetramethoxysilane, octamethylcyclotetrasiloxane, and tetraethoxysilane can be used.
A method for forming the oxide thin film will be described later. Examples of the oxide thin film that can be used include a silicon oxide layer, a magnesium fluoride layer, and a silicon oxyfluoride layer. In addition, the oxide thin film is not necessarily a single layer, and a plurality of different layers are laminated to form a layer structure having a refractive index of 1.4 to 1.55 as a whole. It is also possible to use a thin film.
[0016]
The oxide thin film used in the present invention is preferably a silicon oxide layer for the following reasons. The silicon oxide layer has a relatively easy refractive index of 1.4 to 1.55, and is excellent in moisture resistance and heat resistance even under conditions by plasma CVD, and a thin film with a stable refractive index is productive. It is because it can be formed well.
The composition of the silicon oxide layer does not have to be simply SiOx, and may be a silicon oxide layer (SiOxCy) containing carbon. This is because the refractive index can be more easily adjusted to a desired range by containing carbon in the silicon oxide layer.
[0017]
The thickness of the oxide thin film is about 10 to 1000 nm, preferably in the range of 10 to 200 nm. If the film thickness is too small, the antireflection effect cannot be exerted by laminating with layers having different refractive indexes, and if the film thickness is too large, deformation of the substrate or peeling of the layer may occur due to the pressure of the layer. Absent.
In general, when the transparent laminated film of the present invention is used as an antireflection film, it is desirable that the oxide thin film is the uppermost layer and laminated with a layer having a refractive index different from that of the oxide thin film.
[0018]
(Silicon oxide layer)
The transparent laminated film of the present invention can form an antireflection film in combination with a high refractive index layer or a low refractive index layer using a silicon oxide layer 4 as a middle refractive index layer on a substrate. . However, it is preferable to stack the silicon oxide layer, the high refractive index layer, and the low refractive index layer in this order on the base material because reflection of light can be efficiently prevented.
As this silicon oxide layer, a silicon oxide layer with few impurities, a carbon-containing silicon oxide layer, Al₂O_Three, SiN, SiON, ZrO₂, SiO₂ZnO₂And the like in which the fine particles are dispersed in a silicon oxide layer. In addition, the silicon oxide layer is not necessarily a single layer, and a plurality of different layers are laminated to form a layer structure having a refractive index of 1.5 to 1.8 as a whole. It can also be a silicon layer.
[0019]
The silicon oxide layer can be formed by a plasma CVD method, a vapor deposition method, a sputtering method, or the like. The thickness of the silicon oxide layer is about 10 to 1000 nm, and preferably in the range of 10 to 200 nm. If the film thickness is too small, the antireflection effect can hardly be expected by laminating with layers having different refractive indexes, and if the film thickness is too large, base material deformation or layer peeling may occur due to the layer pressure. It is not preferable.
The silicon oxide layer of the middle refractive index layer used in the present invention preferably has a refractive index of 1.55 to 1.8 (wavelength λ = 550 nm) and a film thickness of 10 to 200 nm.
[0020]
(High refractive index layer)
In the transparent laminated film of the present invention, the high refractive index layer 5 can be used as a constituent element of the transparent laminated film (antireflection film) provided on the substrate, and is combined with the oxide thin film that is the low refractive index layer described above. Therefore, reflection of light can be efficiently prevented due to the difference in refractive index. The position of the high refractive index layer in the transparent laminated film is not particularly limited, but the low refractive index layer and the high refractive index layer can more efficiently prevent light reflection if they are in contact with each other. It is preferable to provide it under the low refractive index layer.
[0021]
The thin film that can be used as the high refractive index layer is not particularly limited as long as it is transparent in the visible light range and has a refractive index of 1.80 or more (λ = 550 nm). . Specifically, as the high refractive index layer, titanium oxide, ITO (indium / tin oxide) layer, Y₂O_ThreeLayer, In₂O_ThreeLayer, Si_ThreeN_FourLayer, SnO₂Layer, ZrO₂Layer, HfO₂Layer, Sb₂O_ThreeLayer, Ta₂O_FiveLayer, ZnO layer, WO_ThreeAmong them, titanium oxide or an ITO layer exhibiting high resistance is particularly preferable.
The high refractive index layer can be formed by plasma CVD, vapor deposition, sputtering, or the like. The thickness of the high refractive index layer is about 5 to 300 nm, preferably in the range of 10 to 150 nm. If the film thickness is too small, the antireflection effect can hardly be expected by laminating with layers having different refractive indexes, and if the film thickness is too large, base material deformation or layer peeling may occur due to the layer pressure. It is not preferable.
[0022]
(Hard coat layer)
The hard coat layer 7 is formed for the purpose of imparting strength to the transparent laminated film of the present invention. The material for forming the hard coat layer is a material that is transparent in the visible light region in the same manner as the plastic film substrate, and a material that can give strength to the transparent laminated film is required. It is preferable to show a hardness of “H” or higher in the pencil hardness test shown in JIS K5400.
[0023]
Specifically, it is preferable to use a thermosetting resin and / or an ionizing radiation curable resin, and more specifically, those having an acrylate-based functional group, for example, a relatively low molecular weight polyester, polyether, (Meth) acrylates of polyfunctional compounds such as acrylic resins, epoxy resins, polyurethanes, alkyd resins, spiroacetal resins, polybutadienes, polythiol polyene resins, polyhydric alcohols (hereinafter, acrylates and methacrylates are referred to as (meth) acrylates) A monofunctional monomer such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, vinyltoluene, N-vinylpyrrolidone, and a polyfunctional monomer. For example, trimethylol pro N-tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6 -Those containing a relatively large amount of hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. are used.
[0024]
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.
[0025]
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.
[0026]
The film thickness of the hard coat layer as described above is usually in the range of 1 to 30 μm, and the formation method is not particularly limited, and a normal coating method can be used. If the thickness of the hard coat layer is too thin, it will not be possible to maintain the hardness of each layer formed on it, and if it is too thick, the flexibility of the entire transparent laminated film will be reduced, and it will take time to cure, etc. Lead to a decline.
[0027]
(Anti-fouling layer)
The transparent laminated film of the present invention may be provided with an antifouling layer 8 for preventing contamination of the upper surface of the antireflection film as the uppermost layer. The antifouling layer is formed in order to prevent dust or dirt from adhering to the antireflection film disposed on the front surface of the display panel, or to facilitate removal even if adhering. Specifically, within a range that does not reduce the antireflection function, apply a very thin coating such as a surfactant such as a fluorosurfactant, a paint containing a fluororesin, a release agent such as silicone oil, or wax, and the excess amount. Wipe away. Although the antifouling layer may be formed as a permanent layer, it may be formed by application whenever necessary. The thickness of the antifouling layer is preferably about 1 to 10 nm.
The formation method can use a normal coating method, and is not particularly limited.
[0028]
(Method for producing transparent laminated film)
  The method for producing a transparent laminated film in the present invention is a method in which a transparent oxide thin film is formed on a base material made of a plastic film by a plasma CVD method.Silicon compound gasOxygen gas, inert gas, and the oxygen gasSilicon compound gasFlow rate ratio (oxygen gas /Silicon compound gas) Is 0.5 to 10, and the flow rate ratio of inert gas to oxygen gas (inert gas / oxygen gas) is 0.05 to 0.7,Silicon compound gasMean free path of the gas molecules of the whole gas mixed with (λ = kT / πpd²√2) under the condition of 0.7 cm to 5 cm,Silicon oxide layerOn the substrate,Silicon oxide layerIs made to have a refractive index of 1.4 to 1.55 (wavelength λ = 550 nm) and a surface roughness Ra of 3 nm or more and 30 nm or less. Mean free path of gas molecules as defined above (λ = kT / πpd)²In the formula (2), λ represents the mean free path, k represents the Boltzmann constant, T represents the gas temperature, p represents the gas pressure, and d represents the gas molecular diameter (diameter).
[0029]
One embodiment of the method for producing the transparent laminated film will be described with reference to FIG.
First, the web-shaped transfer target (base material) 2 is unwound from the unwinding section 10 and introduced into the plasma CVD reaction chamber 13 in the vacuum vessel 12. The entire reaction vessel 12 is evacuated by a vacuum pump 14. At the same time, the reaction chamber 13 is supplied with a gas obtained by gasifying a raw material such as a silicon compound of an oxide thin film at a predetermined flow rate from a gas inlet 15, an oxygen gas, and a raw material gas of the oxide thin film such as helium, neon, and argon. Inert gas is supplied, and the inside of the reaction chamber 13 is always filled with these mixed gases at a constant pressure.
[0030]
Next, the transfer target 2 unwound from the substrate unwinding section 10 and introduced into the reaction chamber 13 is wound around the film-forming drum 18 through the reverse roll 16 and is synchronized with the rotation of the film-forming drum 18. While being sent in the direction of the reversing roll 17. At this time, the temperature of the film-forming drum 18 can be controlled. At this time, the surface temperature of the transfer target 2 and the surface temperature of the film-forming drum 18 are substantially equal. Therefore, it is possible to arbitrarily control the surface temperature of the transfer object 2 on which the oxide thin film is deposited during plasma CVD, that is, the film formation temperature of plasma CVD. In this example, the film forming temperature when the oxide thin film 3 is formed on the transfer target 2 by plasma CVD is displayed by the surface temperature of the film forming drum 18 at that time. The surface temperature of the transfer object 2, that is, the film formation temperature of plasma CVD is desirably controlled to a temperature within the range of −10 to 150 ° C.
[0031]
An RF voltage is applied between the electrode 19 and the film forming drum 18 by a power source 20. At this time, the frequency of the power source is not limited to a radio wave, and an appropriate frequency from a direct current to a microwave can be used. Then, by applying an RF voltage between the electrode 19 and the film-forming drum 18, a plasma 21 is generated around these electrodes. Then, a raw material gas such as a silicon compound of an oxide thin film and an oxygen gas react in the plasma 21 while being mixed with an inert gas, and the raw material such as a silicon compound is wound around the film-forming drum 18. Depositing on the body 2 forms an oxide thin film 3. Thereafter, the transfer object 2 having the oxide thin film 3 formed on the surface thereof is wound up by the substrate winding unit 11 through the reverse roll 17.
[0032]
  When an oxide thin film is formed on a transfer target (plastic film substrate), the source gas and oxygen are combined in the reaction chamber, and the silicon oxide thin film tends to become fine particles. Since the inert gas is introduced, the inert gas improves the uniformity of the mixed gas in the reaction between the raw material gas and the oxygen gas, thereby stabilizing the discharge voltage and preventing the oxide thin film from becoming fine particles. Can do. And in that case, by adjusting each ratio in the mixed gas of source gas, oxygen gas, inert gas, etc.,Source gas, oxygen gas, and inert gas are introduced into the reaction chamber, the flow rate ratio of oxygen gas to source gas (oxygen gas / source gas) is set to 0.5 to 10, and the flow rate ratio of inert gas to oxygen gas (Inert gas / oxygen gas) under the condition of 0.05 to 0.7,Mean free path of gas molecules in the whole gas in the reaction chamber (λ = kT / πpd²√2) is within the range of 0.7 cm to 5 cm, the refractive index is 1.4 to 1.55 (wavelength λ = 550 nm) and the surface roughness Ra is 3 nm to 30 nm on the substrate. A certain oxide thin film can be easily formed.
[0033]
As described above, the transferred material 2 in which the oxide produced by the chemical reaction of the source gas and the oxygen gas in the presence of the inert gas by the plasma 21 is cooled to an appropriate temperature by the film-forming drum 18. Since the oxide thin film is deposited thereon, the transfer target 2 is exposed to a high temperature, and the oxide thin film 3 can be formed without being stretched, deformed, or curled.
Further, in the above plasma CVD method, the refractive index and film thickness of the oxide thin film 3 to be formed can be controlled over a wide range by controlling the material gas flow rate / pressure, the discharge conditions, and the feed speed of the transfer target 2. Therefore, a film having desired optical characteristics can be obtained without changing the material.
The plasma CVD apparatus 9 used in the present invention is not particularly limited as long as the temperature of the transfer target can be controlled, and the power supply frequency and the plasma generation method are not particularly limited.
[0034]
  The raw material for the oxide thin film is evaporated by a liquid vaporizer and introduced into the reaction chamber in the form of a raw material gas. Oxygen gas and inert gas are also introduced into the reaction chamber. This oxygen gas plays a role as a reaction gas for reacting with the raw material gas to produce an oxide thin film. Further, the inert gas improves the uniformity of the mixed gas in the reaction between the source gas and the oxygen gas, and as a result, stabilizes the discharge voltage and prevents the oxide thin film from becoming fine particles. The flow rate ratio of oxygen gas to source gas (oxygen gas / source gas) is 0.5 to 10It is.When the ratio of oxygen gas is smaller than this range, it is difficult to obtain an oxide thin film having a low refractive index. Moreover, when the flow ratio of oxygen gas is large, fine particles of the oxide thin film are likely to be generated. Examples of the inert gas introduced into the reaction chamber include gases such as helium, neon, and argon, which have no activity with the raw material gas for the oxide thin film. The flow rate ratio of inert gas to oxygen gas (inert gas / oxygen gas) is 0.05 to 0.7.It is.When the ratio of the inert gas is smaller than this range, the function of improving the uniformity of the mixed gas by the inert gas, stabilizing the discharge voltage, and preventing the oxide thin film from becoming fine particles becomes insufficient. Further, when the flow rate ratio of the inert gas is large, the oxygen gas concentration is relatively lowered, the reactivity between the source gas and the oxygen gas is lowered, and it is difficult to form a CVD thin film.
[0035]
A suitable pressure in the reaction chamber is 1 Torr or less. This is because when the pressure is higher than 1 Torr, there is a problem that the mechanical strength of the formed oxide thin film is lowered. The partial pressure of the source gas is 10^-1It is preferably less than or equal to Torr. The partial pressure of the source gas is 10^-1When it becomes larger than Torr, there arises a problem that the raw material of the oxide thin film is liquefied in the reaction chamber.
Since the temperature of the film formation drum can be controlled, it is possible to arbitrarily control the surface temperature of the transfer target on which the oxide thin film is deposited during plasma CVD, that is, the film formation temperature of plasma CVD. The film forming temperature is preferably -10 to 150 ° C. If this temperature is lower than −10 ° C., the refractive index of the oxide thin film formed is not preferable. In addition, if the film forming temperature exceeds 150 ° C., problems such as elongation, deformation, curl, etc. at the time of film formation because it becomes higher than the heat deformation temperature of the plastic film of the base material that can be used in the present invention are not preferable. .
Furthermore, even when the anti-reflection film is required to have a high quality that does not allow slight swell, deformation, or elongation, or when the plastic film of the substrate is less than 10 μm and is easily stretched and deformed by heat, it is −10 ° C. It is particularly desirable to perform plasma CVD film formation of an oxide thin film at a temperature not higher than Tg of the plastic film.
[0036]
In the example shown in FIG. 7, the temperature of the transfer medium is controlled by bringing the transfer medium into close contact with the film formation drum and controlling the temperature of the film formation drum. However, the present invention is not limited to this. If it is a method that can control the temperature of the transferred object when a film is formed by plasma CVD, for example, a method of controlling the temperature of the transferred object by controlling the atmospheric temperature in the reaction chamber, There is no particular limitation on the method of bringing the transfer body into a reaction chamber after the temperature of the transfer medium is set to a predetermined temperature in advance.
The transparent laminated film of the present invention forms an oxide thin film that is a low refractive index layer by the plasma CVD method described above. A hard coat layer can be formed on a substrate in advance by coating or the like. In addition, a medium refractive index layer and a high refractive index layer are formed on the substrate as other layers by a plasma CVD method, a vapor deposition method, a sputtering method, or the like, if necessary. Furthermore, an antifouling layer can be formed on the outermost surface of the transparent laminated film by coating or the like.
[0037]
【Example】
The present invention will be described in more detail with reference to examples.
Example 1
Using the apparatus shown in FIG. 7, an oxide thin film as a silicon oxide layer was formed on a polyethylene terephthalate (PET) film having a thickness of 75 μm as a base plastic film. As the source gas, HMDSO vaporized at 150 ° C. using a liquid vaporizer was used, and oxygen gas and helium gas were mixed and introduced into the reaction chamber from the source gas inlet. The flow rates of HMDSO, oxygen gas, and helium gas are as follows, and the mean free path of the gas molecules in the entire gas in the reaction chamber (λ = kT / πpd)²√2) was 0.7 cm or more and 5 cm or less. Specifically, the mean free path of gas molecules in the entire gas was 3 cm. The plasma CVD apparatus of FIG. 7 used this time is a capacitive coupling type, and a 13.56 MHz RF power source was used as a high frequency power source. Further, the feeding speed of the plastic film as the base material during continuous film formation is 1 m / min. Other conditions are described below.
[0038]
<Film formation conditions>
Applied power 2kW
HMDSO (source gas) 1 slm
Oxygen gas flow rate 1 slm
Helium gas flow rate 0.4 slm
Deposition drum surface temperature (deposition temperature) 30 ° C
[0039]
  Above gas flow unitslmIs a standard cubic litterper minute. Various measurement results such as the film thickness, refractive index, and surface roughness of the silicon oxide thin film that is an oxide thin film formed on the polyethylene terephthalate film under the above conditions are shown below.
[0040]
<Oxide thin film measurement results>
Film thickness 240nm
Deposition rate 240nm ・ m / min
Refractive index (λ = 550 nm) 1.45
Surface roughness Ra 10nm
[0041]
<Apparatus used for oxide thin film measurement>
Film thickness measurement Ellipsometer
Model number UVISEL^TM  Manufacturer JOBIN YVON
Refractive index measurement Ellipsometer
Model number UVISEL^TM  Manufacturer JOBIN YVON
Surface roughness measurement Nanopics
Manufacturer Seiko Instruments
[0042]
As shown in the measurement results of the oxide thin film by the plasma CVD method described above, at a film formation temperature of 30 ° C., a homogeneous film having a refractive index of 1.45 does not become fine particles at a film formation speed of 240 nm · m / min. It could be formed on a polyethylene terephthalate film. Further, the polyethylene terephthalate film was in a good state with little elongation and no deformation.
[0043]
(Example 2)
Using the apparatus shown in FIG. 7, an oxide thin film as a silicon oxide layer was formed on a polyethylene terephthalate (PET) film having a thickness of 75 μm as a base plastic film. As source gas, HMDSO vaporized at 150 ° C. using a liquid vaporizer was used, oxygen gas and argon gas were mixed and introduced into the reaction chamber from the source gas inlet. The flow rates of HMDSO, oxygen gas, and argon gas are as follows, and the mean free path of the gas molecules in the entire gas in the reaction chamber (λ = kT / πpd)²√2) was 0.7 cm or more and 5 cm or less. Specifically, the mean free path of gas molecules in the entire gas was 4 cm. Further, the feeding speed of the plastic film as the base material during continuous film formation is 1 m / min. Other conditions are described below.
[0044]
<Film formation conditions>
Applied power 1.0 kW
HMDSO (source gas) 1 slm
Oxygen gas flow rate 1 slm
Argon gas flow rate 0.4 slm
Deposition drum surface temperature (deposition temperature) 30 ° C
[0045]
  Above gas flow unitslmIs a standard cubic litterper minute. Various measurement results such as the film thickness, refractive index, and surface roughness of the silicon oxide thin film that is an oxide thin film formed on the polyethylene terephthalate film under the above conditions are shown below.
[0046]
<Oxide thin film measurement results>
Film thickness 220nm
Deposition rate 220nm ・ m / min
Refractive index (λ = 550 nm) 1.46
Surface roughness Ra 10nm
[0047]
<Apparatus used for oxide thin film measurement>
Film thickness measurement Ellipsometer
Model number UVISEL^TM  Manufacturer JOBIN YVON
Refractive index measurement Ellipsometer
Model number UVISEL^TM  Manufacturer JOBIN YVON
Surface roughness measurement Nanopics
Manufacturer Seiko Instruments
[0048]
As shown in the measurement results of the oxide thin film by the plasma CVD method described above, at a film formation temperature of 30 ° C., a homogeneous film having a refractive index of 1.46 is formed into a fine particle at a film formation speed of 220 nm · m / min. It could be formed on a polyethylene terephthalate film. Further, the polyethylene terephthalate film was in a good state with little elongation and no deformation.
[0049]
(Example 3)
A hard coat layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer were formed on the following plastic film substrate to prepare a transparent laminated film, that is, an antireflection film. The conditions for forming each layer are as follows.
[0050]
<Plastic film>
Triacetylcellulose thickness 80μm
[0051]
<Hard coat layer>
UV curable resin PET-D31 (manufactured by Dainichi Seika Kogyo Co., Ltd.)
Formed by coating.
UV curing condition 480mJ
Thickness 6μm
[0052]
<Medium refractive index layer>
A carbon-containing silicon oxide layer was formed by a plasma CVD method.
Refractive index is 1.55 to 1.8 (wavelength λ = 550 nm)
[0053]
<High refractive index layer>
An ITO layer was formed by sputtering.
Refractive index 1.85 (wavelength λ = 550 nm)
[0054]
<Low refractive index layer>
The silicon oxide layer was formed by the plasma CVD method in the same manner as the formation of the oxide thin film in Example 1.
[0055]
The transparent laminated film formed under the above conditions had no slight elongation or deformation of the plastic film. The reflection spectral characteristics of the transparent laminated film prepared under the above conditions are shown in FIGS. From FIG. 8, 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 0.3%, which was a sufficient value as an antireflection film. Further, as shown in FIG. 9, the transmittance near 550 nm, which is easy for humans to detect, was high, and no white turbidity was visually observed.
[0056]
Spectral reflectance and transmittance were measured with the following apparatus.
Spectral reflectance measurement Spectrophotometer
Model number UV-3100PC Manufacturer Shimadzu
[0057]
In addition, the film thickness of the laminated film formed in the above embodiment was set so that the visibility reflectance was minimized in consideration of the optical characteristics of each layer. For example, in the high refractive index layer and the low refractive index layer shown in Example 3, a desired film thickness is obtained by adjusting the film feed speed when forming each layer.
[0058]
【The invention's effect】
  The transparent laminated film of the present invention is formed in a reaction chamber in a plasma CVD method when a transparent oxide thin film is formed on a substrate made of a plastic film by a plasma CVD method.Silicon compound gas,Oxygen gas and inert gas are introduced, and the oxygen gas andSilicon compound gasFlow rate ratio (oxygen gas /Silicon compound gas) Is 0.5 to 10, and the flow rate ratio of inert gas to oxygen gas (inert gas / oxygen gas) is 0.05 to 0.7,Silicon compound gasMean free path of the gas molecules of the whole gas mixed with (λ = kT / πpd²√2) When the condition is 0.7 cm or more and 5 cm or less, the inert gas is reduced.Silicon compound gasImproves the uniformity of the gas mixture in the reaction of oxygen with oxygen gas, resulting in a stable discharge voltage and a thin oxide filmIs a silicon oxide layerIt was possible to prevent the formation of fine particles. This makes it possible to form an oxide thin film that is uniform and has a stable low refractive index on a substrate, and is laminated with a high refractive index layer to provide a transparent laminate with an antireflection function that sufficiently reduces external light reflection. A film, that is, an antireflection film can be produced while maintaining stable quality.
[Brief description of the drawings]
FIG. 1 is a schematic view showing one embodiment which is a transparent laminated film of the present invention.
FIG. 2 is a schematic view showing another embodiment of the transparent laminated film of the present invention.
FIG. 3 is a schematic view showing another embodiment which is a transparent laminated film of the present invention.
FIG. 4 is a schematic view showing another embodiment which is a transparent laminated film of the present invention.
FIG. 5 is a schematic view showing another embodiment which is a transparent laminated film of the present invention.
FIG. 6 is a schematic view showing another embodiment which is a transparent laminated film of the present invention.
FIG. 7 is a schematic view of a plasma CVD apparatus.
8 is a reflection spectral characteristic of Example 3. FIG.
9 is a transmission spectral characteristic of Example 3. FIG.
[Explanation of symbols]
1 Transparent laminated film
2 Plastic film substrate
3 Transparent oxide thin film
4 Silicon oxide layer
5 High refractive index layer
6 Antireflection film or transparent laminated film
7 Hard coat layer
8 Antifouling layer
9 Plasma CVD equipment
10 Substrate unwinding part
11 Base material winding part
12 Vacuum container
13 Reaction chamber
14 Vacuum pump
15 Gas inlet
16 Reverse roll
17 Reverse roll
18 Drum for film formation
19 electrodes
20 Power supply
21 Plasma

Claims (8)

In a method for producing a transparent laminated film in which a transparent oxide thin film is formed by a plasma CVD method on a substrate made of a plastic film, a silicon compound gas , an oxygen gas, and an inert gas are introduced into a reaction chamber in the plasma CVD method, flow ratio of the oxygen gas and the silicon compound gas (oxygen gas / silicon compound gas) is 0.5 to 10, also the flow rate of the inert gas and oxygen gas (inert gas / oxygen gas) is 0. Under the condition of 05 to 0.7, the silicon oxide layer is formed under the condition that the mean free path (λ = kT / πpd ² √2) of the gas molecules of the whole gas mixed with the silicon compound gas is 0.7 cm or more and 5 cm or less. the provided on a substrate, the refractive index of 1.4 to 1.55 (wavelength lambda = 550 nm) of the silicon oxide layer, the surface roughness Ra 3 nm or more, transparency, characterized by the 30nm or less Method of manufacturing a layer film.   A transparent laminated film comprising a transparent oxide thin film provided on a plastic film substrate by the method for producing a transparent laminated film according to claim 1.   A silicon oxide layer having a refractive index of 1.55 to 1.8 (wavelength λ = 550 nm) and a film thickness of 10 to 200 nm on the substrate, and a high refractive index having a refractive index of 1.8 or more (wavelength λ = 550 nm). A transparent laminated film in which the oxide layer according to claim 2 is laminated in this order.   A high refractive index layer, a refractive index of 1.4 to 1.55 (wavelength λ = 550 nm) and a film thickness of 10 to 200 nm are laminated on the substrate in the order of the oxide thin films, or A transparent laminated film, wherein the high refractive index layer, the oxide thin film, the high refractive index layer, and the oxide thin film are laminated in this order on a substrate.   The transparent laminated film according to any one of claims 2 to 4, wherein a hard coat layer is formed between the substrate and a layer provided on the substrate, that is, an antireflection film. .   The transparent laminated film according to any one of claims 1 to 5, wherein an antifouling layer is formed on the outermost surface of the antireflection film of the transparent laminated film.   The transparent laminated film according to any one of claims 1 to 6, wherein the substrate is a uniaxial or biaxially stretched polyester film or a triacetyl cellulose film.   The transparent laminated film as described in any one of Claims 1-7 is an antireflection film, The antireflection film characterized by the above-mentioned.

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