JP2004258394A - Optical functional film, anti-reflection film, polarizing plate, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical functional film and an anti-reflection film which can be used for surfaces of not only various display devices such as a liquid crystal display device, an organic EL display device, and an inorganic EL display device for normal use but also various flexible display devices because being able to maintain optical characteristics (anti-reflection function) even in such a state that stress is applied. <P>SOLUTION: The optical functional film has at least one layer of a light-transmissive film formed on a flexible substrate directly or another layer between them, is free from film cracks or peeling and also maintains optical functionality when subjected to the cylindrical mandrel bend test based on JIS K 5600-5-1 and has such flexibility that the change rate of a maximum height difference of the light-transmissive film is ≤30%, and the anti-reflection film, a polarizing plate, and a display device use the optical functional film. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical functional film, an antireflection film, a polarizing plate, and a display device. More specifically, various displays such as a word processor, a computer, and a television, a surface of a polarizing plate used for a liquid crystal display device, and transparent plastic sunglasses. Used for lenses, prescription eyeglass lenses, optical lenses such as viewfinder lenses for cameras, covers for various instruments, windows for automobiles, trains, etc. The present invention relates to an optically functional film and an antireflection film which are excellent in flexibility and optical functionality.
[0002]
[Prior art]
BACKGROUND ART Conventionally, transparent substrates such as glass and plastic have been used for displays such as curve mirrors, rearview mirrors, goggles, window glasses, televisions, personal computers and word processors, and various other commercial displays.
The transparent base material is provided with an anti-reflection function in order to read characters, figures, and other information through the base material and to prevent light from being reflected on the surface of the base material. .
In order to impart an antireflection function to a transparent substrate, for example, an optical functional film made of an inorganic compound such as silicon oxide (hereinafter sometimes referred to as “silica”) or zirconium oxide is applied to the transparent substrate. It is known to form.
For example, as a technique for providing an anti-reflection film for a plastic optical component, a three-layer deposition film of a first layer, a second layer, and a third layer is formed in order from the surface side to the air side to form the anti-reflection film. The plastic optical component according to claim 1, wherein the first layer is made of a mixture of silicon monoxide and zirconium oxide, the second layer is made of zirconium oxide, and the third layer is made of silicon dioxide. An antireflection film has been proposed (for example, see Patent Document 1).
Further, as a technique for providing a silica layer composed of an organosilicon compound and an antireflection film using the silica layer, it is 1.40 to 1.46 (λ = 550 nm), and the composition of the layer is SiOxCy: H (x = 1.6-1.9, y = 0.2-1.0), and an antireflection film in which the silica layer is the outermost layer of the antireflection laminate is proposed. (For example, see Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 6-87081
[Patent Document 2]
JP-A-2002-103507
[0004]
On the other hand, the demand for thin, inexpensive, and portable IT devices has been increasing, and for example, new displays such as bendable flexible displays have been proposed.
[0005]
[Problems to be solved by the invention]
However, the conventional anti-reflection film cannot follow the flexible base material even when formed and used on the flexible base material of the flexible display, and as a result, the film cracks and peels off. There is a drawback that the occurrence thereof causes a significant decrease in optical functionality such as antireflection.
[0006]
[Means for Solving the Problems]
Therefore, the present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the present invention has disclosed a light-transmitting film directly on a flexible substrate or at least one layer through another layer. When formed and subjected to a bending test using a cylindrical mandrel method based on JIS K 5600-5-1, no cracking or peeling of the light-transmitting film is observed, and the optical functionality is improved. The optical functional film is characterized in that the optical functional film is maintained and has a flexibility in which the rate of change of the maximum height difference of the light-transmitting film is 30% or less. When an optically functional film such as an anti-reflection film is formed on the substrate, the optically functional film can be maintained even if it is strongly bent. Therefore, a liquid crystal display device, an organic electroluminescence (hereinafter, also referred to as “EL”) which is generally used. )) Display device, inorganic EL display device, PDP Even if it is used not only on the surface of various display devices such as a plasma display) and a polarizing plate, but also on the surface of a flexible various display device, it can flexibly follow and maintain optical functionality such as anti-reflection. It is.
Further, according to the present invention, in the optical transmission film before and after the bending test, the color difference (ΔE *) in the L * a * b * color system is 0.5 or less. A functional membrane can be provided.
The optical functional film has a refractive index of 1.5 to 2.4 (wavelength λ = 550 nm), a film thickness of 30 to 200 nm, and SiNxCyOz (x is 0.2 ≦ x ≦ 2.0). , Y is a silica film represented by a composition formula of 0.5 ≦ y ≦ 1.5 and z is 0.05 ≦ z ≦ 1.5). it can.
Further, the optical functional film is represented by a Si-R bond (R represents an alkyl group, an allyl group, a vinyl group, a phenyl group, a ketone group, a cyano group, or an organic group containing these groups). An optically functional film characterized by using an organosilicon compound containing a bond as a starting material can be provided.
Further, the above-mentioned optical functional film has a Si—O bond (Si represents a silicon atom and O represents an oxygen atom) or a Si—N bond (Si represents a silicon atom and N represents a nitrogen atom). An optical functional film characterized by using an organosilicon compound containing a bond represented as a starting material can be provided.
Further, it is possible to provide an antireflection film characterized in that the optical functional film is formed on a flexible base material directly or via another layer.
In addition, on the flexible base film, directly or through another layer, having a light transmittance, and a middle refractive index layer having a different refractive index from each other, a high refractive index layer, and, An antireflection film in which a low refractive index layer and a low refractive index layer are sequentially laminated, wherein the middle refractive index layer has a refractive index of 1.5 or more and 1.8 or less (wavelength λ = 550 nm), a film thickness of 30 nm or more and 200 nm or less, The high refractive index layer has a refractive index of 1.8 to 2.4 (wavelength λ = 550 nm), a film thickness of 30 to 200 nm, and a low refractive index layer has a refractive index of 1.3 to 1.5. (Wavelength λ = 550 nm), a film thickness of 30 nm or more and 200 nm or less, and wherein the middle refractive index layer or the high refractive index layer is the above-mentioned optical functional film. can do.
Further, on the flexible base film, directly or through another layer, a layer having light transmittance and having different refractive indices, a high refractive index layer and a low refractive index layer Or laminated in the order of a high refractive index layer, a low refractive index layer, a high refractive index layer and a low refractive index layer, the high refractive index layer, the refractive index of the optical functional film 1.8 to 2.4 (wavelength λ = 550 nm), and the low refractive index layer has a refractive index of 1.3 to 1.5 (wavelength λ = 550 nm), a film thickness, and 30 nm to 200 nm. It is possible to provide an antireflection film characterized by being a silicon oxide film.
In addition, it is possible to provide an antireflection film, wherein the other layer is a hard coat layer.
Further, it is possible to provide an antireflection film characterized in that an antifouling layer is laminated on the uppermost layer.
Further, it is possible to provide a polarizing plate, wherein the antireflection film is laminated on a polarizing element.
In addition, the antireflection film, or the polarizing plate is laminated or arranged on the viewing side of the display unit, or a liquid crystal display device, an electroluminescence display device, A display device can be provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in more detail below.
First, an antireflection film for forming the optical functional film according to the present invention on a flexible substrate, and a polarizing plate using the same, and a few examples of the configuration of a display device will be described with reference to the drawings. To explain, FIG. 1 is a schematic cross-sectional view showing a layer configuration which is an embodiment of an optical functional film in which an optical functional film according to the present invention is formed on a flexible base material. FIG. 4 is a schematic cross-sectional view showing a layer configuration which is an embodiment of an antireflection film for forming a multilayer antireflection film including the optical functional film according to the present invention, and FIG. FIG. 5 schematically shows a cross section of a polarizing plate attached to an outer surface of a substrate. FIG. 5 shows a liquid crystal display device in which a display surface is covered with a multilayer antireflection film including an optical functional film according to the present invention. FIG. 6 and FIG. 7 are schematic sectional views showing an example of the present invention. Method of manufacturing the anti-reflection film for forming an optical functional film on a flexible substrate according to a schematic view for explaining the.
[0008]
As shown in FIGS. 1 to 3, the optical functional film 12 according to the present invention has a single layer or a plurality of layers formed on a flexible substrate 30.
After the optical functional film 12 according to the present invention is formed on the flexible base material 30, the film is used as a measurement sample so that the film surface can be bent outward based on JIS K 5600-5-1. After bending at 180 degrees evenly at the same speed for 2 seconds at the same speed for 2 seconds and conducting a bending test by the cylindrical mandrel method, the film surface was visually observed. It is necessary that peeling from the material is not recognized.
In the light-transmitting films before and after the bending test, the color difference (ΔE *) in the L * a * b * color system needs to be 0.5 or less.
The color coordinates and brightness of the L * a * b * color system are based on the XYZ color system defined in JIS Z8701 or X. ₁₀ Y ₁₀ Z ₁₀ Tristimulus value X, Y, Z, or X in color system ₁₀ , Y ₁₀ , Z ₁₀ Can be used to determine L *, a *, and b * according to JIS Z8729. The color is measured by a spectrophotometer based on JIS Z8722.
The color difference (ΔE *) of the optical functional film before and after the bending test according to the present invention can be quantitatively displayed by a spectrophotometer, and the following formula is obtained from L *, a *, and b * of the sample. To calculate ΔE *.
ΔE * ab = [(ΔL *) ² + (Δa *) ² + (Δb *) ² ] ^1/2 However
(ΔL *) i, j = (L *) i− (L *) j
(Δa *) i, j = (a *) i- (a *) j
(Δb *) i, j = (b *) i− (b *) j
i = after bending test
j = Before bending test
Further, the optical functional film according to the present invention was subjected to spectral reflection measurement using a spectrophotometer (model number UV-3100PC manufactured by Shimadzu Corporation).
That ΔE * is 0.5 or less means that the change in the spectral characteristics is small, and the optically functional film can be formed by applying stress or bending to the flexible base material forming the optically functional film. It means that there is no change in the optical characteristics of the flexible polarizing plate, the liquid crystal display device, even if it is used for an electroluminescent display device, the smaller the better, because the optical functions such as anti-reflection are stable. Things.
On the other hand, when the color difference ΔE * value exceeds 0.5, a change in spectral characteristics is large when a stress is applied to the flexible base material. Is undesirably changed.
Furthermore, in a portion where a stress is applied to the flexible base material on which the optical functional film is formed, the rate of change of the maximum height difference of the light-transmitting film before and after the stress can be 30% or less.
The rate of change of the maximum height difference of the light-transmitting film was measured by applying a stress between two points of a maximum height convex portion and a minimum height concave portion on the surface of the film surface using a scanning probe microscope. The maximum height change rate of the film surface before and after the bending test was determined from the following equation, using the values obtained by measuring 10 points at different portions and calculating the average value of the height differences.
E = {([Delta] a- [Delta] b) / [Delta] b} * 100 E: maximum height difference change rate (%)
Δa: height difference (nm) between two points on the film surface after bending test
Δb: height difference between two points on the film surface before bending test (nm)
In the present invention, by forming the above-mentioned flexible optical functional film on a flexible base material, even if the flexible base material forming the optical functional film is strongly bent, it is reflected. This has the advantage that optical functionality such as prevention can be maintained.
On the other hand, if the rate of change of the maximum height difference exceeds 30%, it is not preferable because the unevenness of the surface causes distortion in the reflection characteristics of visible light.
[0009]
As such an optical functional film, for example, the composition is SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1). .5) can be used.
The silica film according to the present invention is not a layer simply composed of silicon oxide (SiOx), but a silicon compound (organic silicon compound) containing organic substances (carbon (C), nitrogen (N), and hydrogen (H)). It consists of.
As described above, by using a silicon compound (organosilicon compound), even when used as a material for the surface of various flexible displays, film cracking or peeling does not occur, and optical characteristics (antireflection function) can be maintained. In terms of handling of the antireflection film, it is preferable because it has favorable flexibility and can have excellent adhesiveness with the lower layer, and the silica film can have a desired refractive index. It is.
On the other hand, if the silica film according to the present invention has a simple composition of silicon oxide (SiOx), it is inferior in flexibility, cannot follow a flexible base material, causes film cracking, peeling, and reflection. This is not preferable because the prevention function is reduced.
Here, the number x of nitrogen atoms (N) bonded to silicon atoms (Si) constituting the silica film of the present invention is preferably 0.2 to 2.0, and more preferably 0.2 to 1.5. .
If the number x of the bonded nitrogen atoms is less than 0.2, it is not preferable because the heat and humidity environment or sunlight causes a change with time and the stability is poor.
On the other hand, when the number x of the nitrogen atoms bonded to the silicon atoms is more than 2.0, the whole silica film becomes hard and the film lacks flexibility, which is not preferable.
The number y of carbon atoms (C) bonded to silicon atoms (Si) constituting the silica film of the present invention is 0.5 to 1.0.
If the number of bonded carbon atoms is less than 0.5, the refractive index (1.46 to 1.55) is the same as that of a mere silica layer (SiOx), and the medium refractive index layer or the high refractive index layer has a high refractive index. It is not preferable because it cannot be suitably used as a refractive index layer.
On the other hand, when the number y of carbon atoms bonded to silicon atoms is more than 1.0, the silica film is colored yellow or the transparency of the silica film is reduced, and the antireflection film of the antireflection film has an antireflection function. And the internal stress of the silica film increases, the whole multilayer film becomes brittle, and the film is easily undesirably cracked or peeled off.
The number z of oxygen atoms (O) bonded to silicon atoms (Si) constituting the silica film according to the present invention is 0.05 to 1.5.
This is because if the number of bound oxygen atoms is less than 0.05, it changes with time due to a moist heat environment or sunlight and lacks stability, which is not preferable.
On the other hand, when the number z of oxygen atoms bonded to silicon atoms exceeds 1.5, the refractive index (1.46 to 1.55) is the same as that of a simple silica layer (SiOx), and the antireflection is prevented. It is not preferable because it cannot be suitably used as a medium or high refractive index layer constituting a film.
[0010]
The optical characteristics (anti-reflection function) required for the optical functional film according to the present invention are a refractive index of 1.5 or more and 2.4 or less (wavelength λ = 550 nm).
The reason why the refractive index at the wavelength of 550 nm is shown is that the wavelength has the highest human sensitivity.
Since the silica film of the present invention is mainly used as a single layer in the antireflection multilayer film constituting the antireflection film, more specifically as a medium refractive index layer or a high refractive index layer, its refractive index Is preferably in the above range.
If the refractive index is less than 1.5, it is suitable as a middle refractive index layer (refractive index is 1.5 to 1.8) or a high refractive index layer (refractive index is 1.8 to 2.4). It is not preferred because it cannot be used for
Further, when the refractive index of the silica film exceeds 2.4 (wavelength λ = 550 nm), the antireflection effect decreases. Therefore, the upper limit of the refractive index of the silica film in the present invention is set to 2.4.
With respect to the thickness of the silica layer, the antireflection film of the present invention is not particularly limited and is not particularly limited as long as it has an antireflection effect, but is preferably 30 nm to 200 nm, and 50 nm. More preferably, it is within the range of 150 nm.
When the layer thickness is less than 30 nm, even if a film is formed on a flexible base material, the anti-reflection effect may not be exhibited in some cases, and it is not preferable. Is not preferred.
[0011]
The middle refractive index layer of the multilayer film constituting the antireflection film according to the present invention has a refractive index of 1.5 or more and less than 1.8 (λ = 550 nm) and has a composition of SiNxCyOz (x is It is preferable that 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5).
[0012]
Further, the high refractive index layer of the multilayer film constituting the antireflection film according to the present invention preferably has a refractive index of 1.8 or more and 2.4 or less (λ = 550 nm), and has a refractive index of 1.9 or more and 2 or less. 0.3 or less, and the composition of the layer is SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5). Is preferred.
[0013]
Here, the medium refractive index layer and the high refractive index layer are names for distinguishing the respective thin layers when the antireflection multilayer films are relatively compared by their respective refractive indices. The layer having a high refractive index is a high refractive index layer, the layer having a relatively low refractive index is a low refractive index layer, and the layer having an intermediate refractive index between the high refractive index layer and the low refractive index layer is a medium refractive index layer. Generally, a refractive index of 1.80 or more is often referred to as a high refractive index layer;
[0014]
Here, as the antireflection film according to the present invention, the outermost layer may be made of silicon oxide, and at least one organosilicon compound may be formed inside the silicon oxide. For example, SiN, An organosilicon compound containing an SiO bond can also be used.
[0015]
Next, the substrate 30 of the antireflection film according to the present invention is located on the opposite surface of the silica film, and is a portion serving as a base of the antireflection film.
The flexible substrate is not particularly limited as long as it is a polymer film that is transparent in the visible light region, and specifically, for example, a triacetyl cellulose film, a diacetyl cellulose film, an acetate butyrate cellulose film, a polyether Sulfone film, polystyrene resin film, polyacrylic resin film, polyurethane resin film, polyester film, polycarbonate resin film, polysulfone film, cyclic olefin resin film, polyether film, trimethylpentene film, polyetherketone film , Polyethersulfone-based film, acrylonitrile film, acrylonitrile-styrene copolymer resin (AS resin) film, acrylonitrile-butadiene-styrene copolymer Fat (ABS resin) film, polyamide resin film, fluororesin film, acetal resin film, a cellulose-based resin film or the like can be used.
Above all, a colorless and transparent stretched film is preferable, and a uniaxial or biaxially stretched polyester film is more preferable because of excellent transparency and heat resistance.
Further, triacetyl cellulose is also preferable in that it has no optical anisotropy.
Usually, the thickness of the flexible substrate is preferably about 6 μm to 188 μm.
The flexible substrate of the present invention may be colored as long as it is essentially transparent, and may be provided with a pattern or character by printing or the like.
[0016]
FIG. 2 is a schematic cross-sectional view showing a layer configuration which is one embodiment of the antireflection film 36 forming the multilayer antireflection film including the optical functional film according to the present invention.
As the antireflection film 36 of the present invention, the outermost layer (the layer on the side opposite to the layer in contact with the base material) is a low refractive index layer 34, and the low refractive index layer 34 has a low refractive index toward the base material 30. The refractive index layer 34, the high refractive index layer 33, the middle refractive index layer 32, the hard coat layer 31, and the substrate 30 are sequentially laminated.
[0017]
Thus, the high refractive index layer in the multilayer antireflection film shown in FIG. 2 has a refractive index of 1.6 or more and 2.4 or less (λ = 550 nm) and a refractive index of 1.8 or more and 2.4. The following is preferred.
The composition of the high refractive index layer is expressed as SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5). Silica layer, titanium oxide layer or silicon oxide layer, ITO (indium / tin oxide) layer, IZO layer, IXO layer, Nb ₂ O ₅ Layer, Ta ₂ O ₅ , A ZnS layer or the like can be used.
[0018]
By using the above silica layer as a high refractive index layer, in the antireflection multilayer film, each is combined with a low refractive index layer provided above the high refractive index layer (in the direction opposite to the base material side). , The reflection of light can be efficiently prevented.
Here, when the silica layer of the present invention is used as the high refractive index layer, when forming the antireflection film, the refractive index of the high refractive index layer is relative to other laminated layers. It is preferable that the refractive index of the high-refractive-index layer is 1.8 to 2.4 (in general, the high-refractive-index layer has a refractive index of 1.8 to 2.4). (λ = 550 nm) is more preferable.
[0019]
The thickness of the high refractive index layer formed by the silica layer of the present invention is not particularly limited, and may be any thickness as long as it can exhibit an anti-reflection effect, and is particularly preferably 30 nm to 200 nm. 50 nm to 150 nm is more preferable. When the thickness of the layer is less than 30 nm, the antireflection effect can hardly be expected, so that it is not preferable. On the other hand, when the thickness of the layer is more than 200 nm, the visible light transmittance is unpreferably reduced.
[0020]
The middle refractive index layer in the antireflection multilayer film shown in FIG. 2 has a refractive index of 1.5 or more and less than 2.4 (λ = 550 nm), and a refractive index of 1.5 or more and less than 1.8. preferable.
The composition of the middle refractive index layer is represented by SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5). Silica layer is used.
[0021]
By using the above silica layer as the middle refractive index layer, the antireflection function can be enhanced in the antireflection multilayer film with a synergistic effect with other thin layers (for example, the low refractive index layer and the like). it can.
[0022]
Here, the position at which the intermediate refractive index layer is provided is not particularly limited in the present invention, and may be provided at any position as long as the antireflection function is improved as the whole antireflection. As shown in FIG. 2, when the high-refractive-index layer and the low-refractive-index layer are in contact, the reflection of light can be more efficiently prevented. Is preferred.
[0023]
The thickness of the middle refractive index layer formed by the silica film of the present invention is not particularly limited, and may be any thickness as long as it can exhibit an antireflection effect. Similarly, 30 nm to 200 nm is particularly preferable, and 50 nm to 150 nm is more preferable. When the thickness of the layer is less than 30 nm, the antireflection effect can hardly be expected, so that it is not preferable. On the other hand, when the thickness of the layer is more than 200 nm, the visible light transmittance is unpreferably reduced.
[0024]
Next, the low refractive index layer provided on the outermost layer (surface opposite to the substrate) of the antireflection multilayer film shown in FIG. 2 is provided to improve the optical characteristics (antireflection function) of the antireflection film. By providing the low refractive index layer as the outermost layer, light can be transmitted efficiently.
[0025]
In the present invention, the low refractive index layer preferably has a refractive index of 1.3 or more and less than 1.5 (λ = 550 nm).
Further, in the antireflection film of the present invention, as described above, since a silica layer having a different refractive index is used as the middle refractive index layer and the high refractive index layer, a silica layer is used as the low refractive index layer. Thus, an antireflection multilayer film is formed, and a thin layer having optical characteristics can be formed only by the silica layer.
Further, instead of the silica layer, magnesium fluoride or silicon oxyfluoride may be used.
By forming the thin film for forming the anti-reflection multilayer film using only the silica layer in this way, the yield can be improved, and not only is the cost favorable, but also the adhesion of each thin layer is improved. Is preferred because
[0026]
The thickness of the low refractive index layer of the present invention is not particularly limited, and may be any thickness as long as it can exhibit an antireflection effect. Similarly, 30 nm to 200 nm is particularly preferable, and 50 nm to 150 nm is more preferable. If the thickness of the layer is less than 30 nm, the antireflection effect can hardly be expected, which is not preferable. On the other hand, if the thickness of the layer is more than 200 nm, the visible light transmittance is undesirably reduced.
[0027]
Further, a hard coat layer 31 can be provided as the antireflection film shown in FIG.
The hard coat layer 31 used in the present invention is a layer formed for the purpose of imparting strength to the antireflection film of the present invention. Therefore, it is not an essential layer depending on the use of the antireflection film.
[0028]
The material for forming the hard coat layer 31 is not particularly limited as long as it is a material that is similarly transparent in the visible light range and can give the antireflection film strength. It is preferable that a pencil hardness test shown in JIS K5600-5-4 shows a hardness of "H" or more.
Specifically, it is preferable to use a thermosetting resin and / or an ionizing radiation-curable resin, and more specifically, a resin having an acrylate-based functional group, for example, a relatively low molecular weight polyester, poly (Meth) acrylates of polyfunctional compounds such as ethers, acrylic resins, epoxy resins, polyurethanes, alkyd resins, spiroacetal resins, polybutadienes, polythiolpolyene resins, and polyhydric alcohols (hereinafter, acrylate and methacrylate are referred to as (meth) And monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, vinyltoluene, and N-vinylpyrrolidone, which are reactive diluents; and polyfunctional monomers. Monomers, such as trimethylol Lopantri (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 hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate and the like are preferably used.
The thickness of the hard coat layer is usually preferably in the range of 1 to 30 μm.
The forming method can use a usual coating method, and is not particularly limited.
[0029]
In addition, although the position where the hard coat layer 31 is provided, the purpose of providing the hard coat is to increase the strength of the antireflection film, and not to improve the antireflection function. It is preferable to set it at a remote position and directly above the substrate.
Further, it is preferable that the layers between the hard coat layer and the base material layer are laminated via an adhesive layer.
[0030]
As the antireflection film of the present invention, an antifouling layer 35 may be provided further on the uppermost silica layer.
The antifouling layer is formed to prevent dust and dirt from adhering to the antireflection film disposed on the front surface of the display panel, or to make it easy to remove even if it adheres. Specifically, a surfactant such as a fluorine-based surfactant, a paint containing a fluorine-based resin, a release agent such as silicone oil, or a wax or the like is applied very thinly within a range that does not lower the antireflection function, and the surplus is applied. Remove by wiping. The antifouling layer may be formed as a permanent layer, or may be applied and formed as needed. The thickness of the antifouling layer 35 is preferably 1 to 30 nm.
When the thickness exceeds 30 nm, an optical effect is generated, and the optical characteristics as an antireflection film are deteriorated.
[0031]
FIG. 3 is a schematic cross-sectional view showing a layer configuration as another embodiment of the antireflection film for forming the multilayer antireflection film including the optical functional film according to the present invention.
As the antireflection film 36 of the present invention, the outermost layer (the layer on the side opposite to the layer in contact with the base material) is a low refractive index layer 34, and the low refractive index layer 34 has a low refractive index toward the base material 30. The refractive index layer 34, the high refractive index layer 33, the low refractive index layer 34, the high refractive index layer 33, the hard coat layer 31, and the substrate 30 are sequentially laminated.
[0032]
The high refractive index layer in the multilayer antireflection film shown in FIG. 3 preferably has a refractive index of 1.8 to 2.4 (λ = 550 nm), and has a refractive index of 1.9 to 2.3 (λ = 550). 550 nm).
The composition of the high refractive index layer is represented by SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5). Silica layer can be used.
Further, as the low refractive index layer, a silica layer having a refractive index of 1.3 or more and less than 1.5 (λ = 550 nm) and having a layer composition represented by SiOx can be used.
In addition, the thickness of each layer formed by the silica film of the present invention is not particularly limited, and may be any thickness as long as it can exhibit an antireflection effect. Similarly to the rate layer, 30 nm to 200 nm is particularly preferable, and 50 nm to 150 nm is more preferable. If the thickness of the layer is less than 30 nm, the antireflection effect can hardly be expected, which is not preferable. On the other hand, if the thickness of the layer is more than 200 nm, the visible light transmittance is undesirably reduced.
[0033]
A method for forming a high refractive index layer, a medium refractive index layer, and a low refractive index layer constituting a single-layer optical functional film or an optical functional multilayer film according to the present invention on a flexible substrate For example, the above materials are formed or laminated by a plasma chemical vapor deposition (CVD) method, a thermal CVD method, a vacuum deposition method, a sputtering method, a wet coating method such as a sol-gel method, or a thin film forming method such as an ion plating method. be able to.
Above all, by using a plasma CVD method, conditions such as a film thickness and a refractive index when forming a silica layer can be relatively easily controlled, and the silica layer of the present invention is formed by an organosilicon compound. When forming a raw material containing an organic substance as described above, a stable thin film can be formed by a plasma CVD method or a sputtering method using the raw material in a gaseous state. This is preferable because it has the advantage that the productivity can be improved because the thin layers can be formed at the same time.
[0034]
FIG. 6 is a schematic diagram for explaining a method of manufacturing an antireflection film for forming an optical functional film on a flexible substrate according to the present invention by a plasma CVD method.
As shown in FIG. 6, as a method for producing a film in which an optical functional film is formed on a flexible substrate using a plasma CVD apparatus, first, a web-like polymer film (flexible substrate) 1 Is unwound from the base material unwinding section 2 and is introduced into the plasma CVD reaction chamber 4 in the vacuum chamber 3.
The whole reaction vessel 3 is evacuated by a vacuum pump 5. At the same time, an organic titanium compound gas and an oxygen gas at specified flow rates are supplied to the reaction chamber 4 from the raw material gas inlet 6, and the inside of the reaction chamber 4 is always filled with these gases at a constant pressure.
[0035]
Next, the polymer film 1 unwound from the substrate unwinding unit 2 and introduced into the reaction chamber 4 is wound around the film forming drum 8 via the reversing roll 7 and is synchronized with the rotation of the film forming drum 8. While being fed in the direction of the reversing roll 7 '.
Next, an RF voltage is applied between the electrode 9 and the film forming drum 8 by the power supply 10.
At this time, the frequency of the power supply is not limited to the radio wave, and an appropriate frequency from DC to microwave can be used.
When an RF voltage is applied between the electrode 9 and the film forming drum 8, a plasma 11 is generated around the two electrodes.
Then, the organosilicon compound gas and the nitrogen gas react in the plasma 11 to generate a compound having a composition formula represented by SiNxCyOz, and the compound is deposited on the polymer film 1 wound around the film forming drum 8, and the SiNxCyOz is used. The silica film 12 shown is formed.
Thereafter, the polymer film 1 having the silica film 12 represented by SiNxCyOz formed on the surface thereof is wound by the base material winding unit 2 'via the reversing roll 7'.
In the plasma CVD method of the present invention, the refractive index, the film thickness, etc. of the formed silica film 12 represented by SiNxCyOz can be controlled in a wide range by controlling the temperature, the flow rate and pressure of the material gas, the discharge conditions, and the speed of feeding the polymer film 1. Thus, a film having desired optical characteristics can be obtained without changing the material.
[0036]
In the present invention, a starting material for forming a silica film includes a Si—R bond (R is an alkyl group, an allyl group, a vinyl group, a phenyl group, a ketone group, a cyano group, or an organic group containing these groups. An organic silicon compound containing a bond represented by the following formula: can be used.
In addition, in addition to the above-mentioned bond, a Si—O bond (Si represents a silicon atom and O represents an oxygen atom) or a Si—N bond (Si represents a silicon atom and N represents a nitrogen atom) is represented by a table. The starting material may be an organosilicon compound containing the bond shown below.
Examples of starting materials for forming a silica film in the present invention include silane, disilane, tetramethylsilane (TMS), hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), and methyltrimethoxysilane. (MTMOS), tetraethylorthosilicate (TEOS), hexamethyldisilane (HMDS), tetramethylcyclotetrasiloxane (TOMCATS), methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, tetramethoxysilane, octamethyl Cyclotetrasiloxane (OMCTS), tetraethoxysilane hexamethyldisilazane (HMDSN), hexamethyldisiloxane (HMDSO), allyldimethyl (diisopropylamino) Silane, allylaminotrimethylsilane, ammonium silicofluoride, anilinotrimethylsilane, 1,3-bis (chloromethyl) tetramethyldisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) diethylsilane, bis (dimethylamino) ) Dimethylsilane, bis (dimethylaminodimethylsilyl) ethane, bis (dimethylamino) diphenylsilane, bis (dimethylamino) methylsilane, bis (dimethylamino) vinylethylsilane, bis (dimethylamino) vinylmethylsilane, bis (ethylamino) ) Dimethylsilane, bis (ethylmethylketoxime) methylisopropoxysilane, bis (methyldiethoxysilylpropyl) amine, N, O-bis (trimethylsilyl) acetamide, N-6,9-bis (tri Tylsilyl) adenine, N, N′-bis (trimethylsilyl) -1,4-butanediamine, bis (trimethylsilyl) carbodiimide, bis (trimethylsilyl) cytosine, N, O-bis (trimethylsilyl) hydroxylamine, 3-cyanopropyl (diisopropyl) ) Dimethylaminosilane, di-n-butyltetramethyldisilazane, (diethylamino) trimethylsilane, (diisopropylamino) trimethylsilane, (N, N′-dimethyl) trimethylsilane, 1,3-divinyltetramethyldisilazane, heptamethyl Disilazane, 1,1,3,3,5,5-hexamethylcyclotrisilazane, 1,2,3,4,5,6-hexamethylcyclotrisilazane, hexamethyldisilazane, nonamethyltrisilazane, octa Methylcyclotet Silazane, n-octyldiisopropyl (dimethylamino) silane, phenethyldimethyl (dimethylamino) silane, phenylbis (dimethylamino) silane, phenylmethylbis (dimethylamino) silane, 1,3,5,7-tetraethyl-2,4 , 6,8-Tetramethylcyclotetrasilazane, tetrakis (diethylamino) silane, tetrakis (dimethylamino) silane, 1,1,3,3-tetramethyldisilazane, 2,2,5,5-tetramethyl-2, 5-dila-1-azacyclopentane, 1,1,3,3-tetraphenyldimethyldisilazane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasilazane, , 2,3-Triethyl-2,4,6-trimethylcyclotrisilazane, tri-n-hexylshi Triethanolamine, N- (trimethylsilyl) acetamide, trimethylsilyl azide, N- (trimethylsilyl) imidazole, triphenyl aminosilane, can be used Si-based compounds such as 1-trimethylsilyl-1,2,4-triazole.
In forming the silica film according to the present invention, in order to easily control the composition ratio, nitrogen gas, oxygen gas, N ₂ O gas, NO ₂ Gas, N ₂ O ₄ Gas, NO gas, or the like may be added.
In addition, an inert gas (for example, an argon gas, a helium gas, or the like) may be added to stabilize a plasma discharge or control a film density.
Further, a reducing gas (for example, hydrogen gas) may be introduced for breaking the Si—C bond.
[0037]
FIG. 7 is a schematic view of another embodiment for explaining a method of manufacturing an antireflection film for forming an optical functional film on a flexible substrate according to the present invention by a plasma CVD method.
For the production of the optical functional film, a plasma CVD apparatus as shown in FIG. 7 can be used.
The plasma CVD apparatus is a capacitively coupled plasma CVD apparatus, and its basic structure and principle are the same as those of the apparatus shown in FIG.
Therefore, also in this apparatus, the web-like polymer film 21 is unwound from the base material unwinding part 22 and introduced into the reaction chambers (a, b, c) in the vacuum vessel 23. Then, a predetermined film is formed on the film forming drum 24 in the reaction chamber, and is wound by the substrate winding unit 26.
[0038]
The difference between the apparatus shown in FIG. 7 and the apparatus shown in FIG. 6 is that in the apparatus shown in FIG. 6, only one reaction chamber for forming an optically functional film on a film is provided. Is characterized in that it has a plurality (three) of reaction chambers. Each of the reaction chambers (a, b, c) is formed by being isolated by an isolation wall 25. 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. Each of the reaction chambers is provided with an electrode plate a1, b1, c1 and a source gas inlet a2, b2, c2.
[0039]
Each reaction chamber (a, b, c) is provided along the outer periphery of the film forming drum 24. This is because the plastic film on which the laminated film is formed is inserted into the reaction chamber synchronously with the film forming drum 24 as described in the example shown in FIG. 6, and forms a multilayer film on the film forming drum. This is because, by arranging in this manner, each film can be continuously laminated.
Although the number of reaction chambers is three in the apparatus shown in FIG. 7, the plasma CVD apparatus used in the method for producing an antireflection film of the present invention is not limited to this, and may be changed as necessary. be able to.
[0040]
According to the plasma CVD apparatus as described above, the film can be formed independently in each reaction chamber by changing the source gas introduced into each reaction chamber. When forming a multilayer film of a silica film and a plastic film on a plastic film, by introducing a gas containing an organic titanium compound into the reaction chamber a, by introducing a gas containing silicon into the reaction chamber b and the reaction chamber c, By the time the plastic film 21 is wound around the substrate winding section 26 via the film forming drum 25, an antireflection film having a titanium oxide film and a silica film formed on the plastic film 21 can be formed.
[0041]
Further, in the above case, the gas introduced into the reaction chamber b and the reaction chamber c is a gas containing silicon, but it is necessary to change the conditions in each reaction chamber, for example, the gas flow rate, the pressure, the discharge conditions, and the like. Thereby, the characteristics of the silica film formed in the reaction chamber b and the reaction chamber c can be changed. The titanium oxide film, the silica film, and the thickness and the refractive index of these films can be freely combined by the device.
[0042]
Further, it is not always necessary to introduce different source gases into the respective reaction chambers. For example, a titanium oxide film is formed by introducing a gas containing an organic titanium compound into all of the reaction chambers a, b, and c shown in FIG. Thereafter, all gases once introduced into the reaction chambers a, b, and c are extracted, and a gas containing silicon is introduced again into the reaction chambers a, b, and c to form a silica film on the titanium oxide film. It is possible.
[0043]
In the present invention, a laminated film in which a titanium oxide film and a silica film are formed on a plastic film may be formed by treating the plastic film a plurality of times with the apparatus shown in FIG. 6 described above. However, as described above, the antireflection film in which the titanium oxide film and the silica film are formed on the plastic film by processing the plastic film at one time using the apparatus shown in FIG. Good. Further, by treating the plastic film a plurality of times using the apparatus shown in FIG. 7, it is possible to obtain a laminated film in which a plurality of titanium oxide films and a plurality of silica films are alternately laminated.
[0044]
FIG. 4 schematically illustrates a cross section of a polarizing plate attached to an outer surface of a flexible substrate on a display surface side.
As shown in FIG. 4, the polarizing plate 40 according to the present invention uses the outermost layer (the layer opposite to the layer in contact with the base material) as the antireflection film layer shown in FIGS. In the direction of the material, an antireflection film layer, for example, in the case of the layer configuration of FIG. An anti-reflection film layer 36 having a layer configuration composed of the base layer 30, a polarizing element 38, and a triacetyl cellulose film 37 (hereinafter referred to as “TAC film”) as a base layer are sequentially laminated via an adhesive. The layers are laminated to form an antireflection film layer 36 / a polarizing element 38 / TAC film layer 37.
Another example of the polarizing plate using the antireflection film of the present invention may be a polarizing element in which the antireflection film of the present invention is laminated on both surfaces of a polarizing element.
The lower surface of the antireflection film of the present invention may be coated with a pressure-sensitive adhesive. In this case, the antireflection film can be used by attaching it to an object to be antireflection, for example, a polarizing element.
[0045]
As the polarizing plate 40 according to the present invention, a polarizing plate with improved antireflection properties can be obtained by laminating the antireflection film 36 of the present invention on the polarizing element 38.
As the polarizing element 38, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, a saponified ethylene-vinyl acetate copolymer film, or the like obtained by dyeing and stretching with iodine or a dye can be used.
When the transparent substrate film of the antireflection film is, for example, a TAC film, the TAC film is subjected to a saponification treatment in order to increase adhesiveness and prevent static electricity in the lamination process. This saponification treatment may be performed before or after applying the hard coat layer to the TAC film.
[0046]
FIG. 5 is a schematic cross-sectional view showing an example of a liquid crystal display device having a display surface covered with a multilayer antireflection film including an optical functional film according to the present invention.
As shown in FIG. 5, in the liquid crystal display device according to the present invention, a polarizing plate shown in FIG. 4, that is, a layer composed of an antireflection film layer 36 / a polarizing element 38 / a TAC film layer 37 is provided on a liquid crystal display element. A polarizing plate having a structure of a TAC film 37 / a polarizing element 38 / a TAC film 37 is laminated on the other surface of the liquid crystal display device. The backlight is illuminated from the lower side in FIG.
The anti-reflection film of the present invention is usually arranged on the emission side of the backlight, but the anti-reflection film of the present invention may be further used instead of the TAC film on the lowermost surface.
In the STN type liquid crystal display device, a retardation plate is inserted between the liquid crystal display element and the polarizing plate. An adhesive layer is provided between each layer of the liquid crystal display device as needed.
[0047]
In addition to the above-mentioned liquid crystal display device using the antireflection film or the polarizing plate according to the present invention, it is used for an organic EL (electroluminescence) display device, an inorganic EL display device, a plasma display, etc. Even when used as a material for the surface of various flexible displays, it does not cause film cracking or peeling, can maintain optical characteristics (anti-reflection function), has favorable flexibility, and has high productivity. Is also excellent.
[0048]
【Example】
Next, the present invention will be specifically described with reference to examples.
(Example 1)
Using the apparatus of FIG. 6, SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5) is placed on a 75 μm-thick polyethylene terephthalate (PET) film, which is a flexible base plastic film. ≦ y ≦ 1.5 and z is 0.05 ≦ z ≦ 1.5) to form a silica film.
As the organic silica compound gas, tetramethylsilane Si (CH) vaporized at 150 ° C. using a liquid vaporizer is used. ₃ ) ₄ And mixed with argon gas and nitrogen gas, and introduced into the reaction chamber from the raw material gas inlet.
The flow rates of the organic silica compound gas, argon gas, and nitrogen gas are shown below.
The plasma CVD apparatus of FIG. 6 used this time is a capacitive coupling type, and a 13.56 MHz RF power supply is used as a high frequency power supply. The feed speed of the plastic film of the flexible base material during continuous film formation is 10 m / min. Other conditions are described below.
<Deposition conditions>
Applied power 1kW
Nitrogen gas flow rate 200sccm
Oxygen gas flow rate 10sccm
Tetramethylsilane gas flow rate 150sccm
Film formation pressure 10Pa
[0050]
The gas flow unit sccm described above is a standard cubic cm per minute.
[0051]
SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y is 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5) formed on a polyethylene terephthalate film under the above conditions. The measurement results of the expressed silica film are shown below.
(Results of Measurement of Silica Film According to the Present Invention)
Thickness 100nm
Film composition (Atomic%) Si: N: C: O = 32.9: 47.4: 16.5: 3.2
Refractive index (λ = 550 nm) 1.71
Thickness average height difference 8nm
<Apparatus Used for Silica Film Measurement>
Ellipsometer for film thickness measurement
Model number UVISELTM Manufacturer JOBIN YVON
Spectral reflection measurement spectrophotometer
Model number UV-3100PC Manufacturer Shimadzu Corporation
Thickness measurement Scanning probe microscope
Model number NPX100 Manufacturer Seiko Instruments
Composition analysis Photoelectron spectrometer
Model number ESCALAB220i-XL Manufacturer VG Scient
Bending test Mandrel bending tester
REF802 maker SEPRO
[0054]
As shown in the result of the formation of the silica film represented by SiNxCyOz (x is 1.4, y is 0.5, and z is 0.1), the homogeneous silica film having a refractive index of 1.71 is made of polyethylene. It could be formed on a terephthalate film.
Further, based on JIS K 5600-5-1 (type 1 test apparatus), the silica film formed above is sandwiched between sample stands so that the silica film on which the sample is formed is on the outside, and the cylindrical mandrel method is used. (Mandrel diameter: 8 mm, bending time: 2 seconds), and the surface of the formed film was visually observed. As a result, no film cracking or peeling was observed in the silica film, and uniform and good film quality was obtained. No difference was observed in the spectral characteristics, and the color difference (ΔE *) in the L * a * b * color system before and after the bending test was 0.08, which was 0.5 or less. And the optical characteristics are maintained.
The maximum height difference of the light transmitting film after the bending test was 11 nm, and the change rate of the maximum height difference of the light transmitting film before and after the bending test was 10%, which was 30% or less. It had flexibility.
(Example 2)
Using the apparatus shown in FIG. 7, a hard coat (ultraviolet curable resin, manufactured by Dainichi Seika Kogyo Co., Ltd.) on a 80 μm-thick triacetyl cellulose (TAC) film which is a plastic film of a flexible base material -D31 ") that was sequentially coated with 6 μm and a middle refractive index layer of 90 nm was used.
Further, a medium refractive index layer was formed in the reaction chamber a shown in FIG. 7, a high refractive index layer was formed in the reaction chamber b, and a low refractive index layer was formed in the reaction chamber c.
A 13.56 MHz RF power supply was used as a high-frequency power supply, and the feed rate of the polymer film as the base material during continuous film formation was 10 m / min. Other conditions are as shown below.
<Medium Refractive Index Layer Deposition Conditions (Reaction Chamber a)>
Applied power 1kW
Argon gas flow rate 100sccm
Nitrogen gas flow rate 500sccm
Oxygen gas flow rate 10sccm
Tetramethylsilane gas flow rate 150sccm
Film formation pressure 10Pa
<High-refractive-index layer deposition conditions (reaction chamber b)>
Applied power 1kW
Hydrogen gas flow rate 100sccm
Oxygen gas flow rate 100sccm
Titanium tetraisopropoxide gas flow rate 150sccm
Film formation pressure 10Pa
<Low Refractive Index Layer Deposition Conditions (Reaction Chamber c)>
Applied power 1kW
Oxygen gas flow rate 100sccm
Tetramethoxysilane gas flow rate 100sccm
Film formation pressure 10Pa
[0059]
The gas flow unit sccm described above is a standard cubic cm per minute.
[0060]
The measurement results of a silica film having an antireflection function as shown in the spectral reflection characteristic diagram of FIG. 8 composed of a low refractive index layer / high refractive index layer / medium refractive index layer structure formed on a TAC film under the above conditions are shown. It is shown below.
The apparatus used for the measurement of the silica film of Example 2 was the same as that of Example 1.
(Results of Measurement of Multilayer Silica Film According to the Present Invention)
Film composition of the middle refractive index layer (Atomic%) Si: N: C: O = 32.2: 46.8: 17.3: 3.7
Composition formula of middle refractive index layer SiNxCyOz (x = 1.45, y = 0.5, z = 0.1)
Film composition of the high refractive index layer (Atomic%) Ti: C: O = 33.4: 40.1: 26.5
Film composition of the low refractive index layer (Atomic%) Si: C: O = 38.3: 8.9: 52.8
Thickness average height difference 15nm
Fig. 8
[0062]
Based on JIS K 5600-5-1, the silica film formed above was sandwiched between sample stands so that the formed silica film was on the outside, and a bending test was performed by a cylindrical mandrel method (mandrel). (Diameter: 8 mm, bending time: 2 seconds), no cracking or peeling was observed in the silica film, uniform and good film quality, and differences in spectral characteristics before and after the bending test were observed. The color difference (ΔE *) in the L * a * b * color system before and after the bending test was 0.1, which was 0.5 or less, and the optical characteristics were maintained. The maximum height difference of the light-transmitting film after the bending test was 17 mm, and the rate of change of the maximum height difference before and after the bending test was 13%. Has flexibility and excellent anti-reflection film properties It was the. The luminous reflectance of the antireflection film was 0.5%.
Further, as a result of actually laminating the obtained antireflection film on the surface of the display, it was found that there was no reflection and the antireflection property was excellent.
(Comparative Example 1)
A silica film was formed under the same conditions as in Example 1 except that the thickness of the silica film was 100 nm and no nitrogen gas was supplied. The device used for the measurement of the silica film was the same as in Example 1. The results are described below.
<Deposition conditions>
Applied power 1kW
Nitrogen gas flow rate 800sccm
Tetramethylsilane gas flow rate 150sccm
Film formation pressure 10Pa
(Results of Measurement of Silica Film According to the Present Invention)
Thickness 100nm
Film composition (Atomic%) Si: N: C = 22.5: 48.7: 28.8
Refractive index (λ = 550 nm) 1.67
Thickness average height difference 12nm
[0066]
As shown in the results of the formation of the silica film represented by SiNxCyOz (x is 2.2, y is 1.28, z is 0), the silica film having a refractive index of 1.67 is formed on the polyethylene terephthalate film. Could be formed.
Further, based on JIS K 5600-5-1, the silica film formed above was sandwiched between sample stands so that the formed silica film was on the outside, and a bending test was performed by a cylindrical mandrel method. (Mandrel diameter, 8 mm, bending time, 2 seconds), the surface of the formed film was visually observed. As a result, the silica film cracked and peeled off from the substrate, and L * a * before and after the bending test. The color difference (ΔE *) in the b * color system was 0.64, which was the optical difference was not maintained because the color difference (ΔE *) exceeded 0.5. The height difference was 35 nm, and the rate of change of the maximum height difference before and after the bending test was 191%, which exceeded 30%, was inferior in flexibility, and was inferior as an antireflection film.
(Comparative Example 2)
A silica film having an antireflection function as shown in the spectral reflection characteristic diagram of FIG. 9 was formed under the same conditions as in Example 2 except for the conditions for forming the medium refractive index layer. The apparatus used for the measurement of the silica film was the same as in Example 2. The results are described below.
(Measurement Result of Silica Film According to the Present Invention)
Film composition of the middle refractive index layer (Atomic%) Si: N: C = 25.1: 53.6: 21.3
Composition formula of middle refractive index layer SiNxCyOz (x is 2.1, y is 0.8, z is 0)
Film composition (Atomic%) of high refractive index layer Ti: C: O = 32: 42.2: 25.8
Film composition (Atomic%) of low refractive index layer Si: C: O = 40.1: 7.5: 52
18nm average height difference
Fig. 9
[0069]
Based on JIS K 5600-5-1, the silica film formed above was sandwiched between sample stands so that the formed silica film was on the outside, and a bending test was performed by a cylindrical mandrel method (mandrel). (Diameter of 8 mm, bending time: 2 seconds), and visually observing the surface of the formed film, no cracking of the silica film and no peeling from the substrate were visually observed, but L * before and after the bending test. The color difference (ΔE *) in the a * b * color system is 0.77, which means that the color difference (ΔE *) exceeds 0.5, the optical characteristics are not maintained, and the light transmission after the bending test is performed. The maximum height difference of the conductive film was 47 nm, and the rate of change of the maximum height difference before and after the bending test was 161%, which exceeded 30%, which was inferior in flexibility and inferior as an antireflection film. Was. Further, the luminous reflectance was 0.4%.
[0070]
【The invention's effect】
As is apparent from the above description, the present invention provides a light-transmitting film formed on a flexible base material directly or at least one layer via another layer, based on JIS K 5600-5-1. Therefore, when the bending test of the cylindrical mandrel method was performed, the light-transmitting film was not cracked or peeled off, and the optical functionality was maintained, and the maximum height of the light-transmitting film was maintained. When an optically functional film characterized by having a flexibility in which the rate of change of the difference is 30% or less, an antireflection film, a polarizing plate, and a display device using the same are produced, the optical characteristics are obtained even when stress is applied. (Anti-reflection function) can be maintained, so it can be used not only for various display devices such as liquid crystal display devices, organic EL display devices, and inorganic EL display devices, but also for flexible display devices as well as the surface of polarizing plates. It ’s good to do That.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a layer configuration which is one embodiment of an optical functional film in which an optical functional film according to the present invention is formed on a flexible substrate.
FIG. 2 is a schematic cross-sectional view showing a layer configuration which is an embodiment of an antireflection film for forming a multilayer antireflection film including an optical functional film according to the present invention.
FIG. 3 is a schematic cross-sectional view showing a layer configuration which is one embodiment of an antireflection film for forming a multilayer antireflection film including an optical functional film according to the present invention.
FIG. 4 schematically illustrates a cross section of a polarizing plate attached to an outer surface of a flexible substrate on a display surface side.
FIG. 5 is a schematic cross-sectional view showing an example of a liquid crystal display device having a display surface covered with a multilayer antireflection film including an optical functional film according to the present invention.
FIG. 6 is a schematic diagram for explaining a method for producing an antireflection film for forming an optically functional film on a flexible substrate according to the present invention by a plasma CVD method.
FIG. 7 is a schematic diagram for explaining a method for producing an antireflection film for forming an optically functional film on a flexible substrate according to the present invention by a plasma CVD method.
FIG. 8 is a spectral reflection characteristic diagram of a multilayer silica film according to Example 2.
FIG. 9 is a spectral reflection characteristic diagram of a multilayer silica film according to Comparative Example 2.
[Explanation of symbols]
1,21,30 Plastic film
2,22 Unwinding part of substrate
2 ', 26 Substrate winding section
3,23 Vacuum container
4, a, b, c reaction chamber
5, 27 vacuum pump
6, a2, b2, c2 Source gas inlet
7, 7 'reversing roll
8, 24 Drum for film formation
9, a1, b1, c1 electrodes
10 Power supply
11 Plasma
12 Optical functional film
25 Isolation Wall
31 Hard coat layer
32 Medium refractive index layer
33 High refractive index layer
34 Low refractive index layer
35 Antifouling layer
36 Anti-reflection film
37 TAC base film
38 Polarizing element
39 LCD device
40 Polarizing plate
41 Backlight unit

Claims (15)

When a light-transmitting film is formed directly on a flexible base material or at least one layer via another layer, and a bending test of a cylindrical mandrel method is performed based on JIS K 5600-5-1. Flexible, in which no cracking or peeling of the light-transmitting film is observed, the optical functionality is maintained, and the rate of change of the maximum height difference of the light-transmitting film is 30% or less. An optical functional film comprising: The color difference (ΔE *) in the L * a * b * color system shown in JIS Z8730 of the light transmitting film before and after the bending test is 0.5 or less. Optical functional film. The optical functional film has a refractive index, 1.5 or more and 2.4 or less (wavelength λ = 550 nm), a film thickness, 30 nm or more and 200 nm or less, SiNxCyOz (x is 0.2 ≦ x ≦ 2.0, y Is a silica film represented by a composition formula of 0.5 ≦ y ≦ 1.5, and z is 0.05 ≦ z ≦ 1.5). Optical functional film. The above-mentioned optical functional film is represented by a Si—R bond (R represents an alkyl group, an allyl group, a vinyl group, a phenyl group, a ketone group, a cyano group, or an organic group containing these groups). The optical functional film according to claim 1, wherein an organic silicon compound containing a bond is used as a starting material. The above-mentioned optical functional film is represented by a Si—O bond (Si represents a silicon atom, O represents an oxygen atom) or a Si—N bond (Si represents a silicon atom, and N represents a nitrogen atom). The optical functional film according to any one of claims 1 to 4, wherein an organic silicon compound containing a bond is used as a starting material. An antireflection film, wherein the optical functional film according to any one of claims 1 to 5 is formed directly or via another layer on a flexible substrate. On the above-mentioned flexible substrate film, directly or through another layer, has a light-transmitting property, and has a middle refractive index layer, a high refractive index layer, and a low refractive index having different refractive indexes from each other. And a refractive index layer having a refractive index of 1.5 to 1.8 (wavelength λ = 550 nm), a film thickness of 30 to 200 nm, and a high refractive index. The refractive index layer has a refractive index of 1.8 to 2.4 (wavelength λ = 550 nm), a film thickness of 30 nm to 200 nm, and a low refractive index layer has a refractive index of 1.3 to 1.5 (wavelength). λ = 550 nm), a film thickness of 30 nm or more and 200 nm or less, and wherein the middle refractive index layer or the high refractive index layer is the optical functional film according to claim 1. Anti-reflection film. On the above-mentioned flexible base film, directly or through another layer, having light transmittance, and a layer having a different refractive index from each other, a high refractive index layer and a low refractive index layer in order. 6. The optical function according to claim 1, wherein the high refractive index layer, the low refractive index layer, the high refractive index layer, and the low refractive index layer are laminated in this order. Among the conductive films, the low refractive index layer has a refractive index of 1.8 or more and 2.4 or less (wavelength λ = 550 nm), and the low refractive index layer has a refractive index of 1.3 or more and 1.5 or less (wavelength λ = 550 nm); An antireflection film, which is a silicon oxide film having a thickness of 30 nm or more and 200 nm or less. The anti-reflection film according to any one of claims 6 to 8, further comprising a hard coat layer. The antireflection film according to any one of claims 6 to 9, wherein an antifouling layer is laminated on the uppermost layer. A polarizing plate, wherein the antireflection film according to claim 6 is laminated on a polarizing element. A liquid crystal display device, wherein the antireflection film according to any one of claims 6 to 10 or the polarizing plate according to claim 10 is laminated or arranged on a viewing side of a display unit. An electroluminescent display device, wherein the antireflection film according to any one of claims 6 to 10 or the polarizing plate according to claim 11 is laminated or arranged on a viewing side of a display unit. A liquid crystal display, wherein the antireflection film according to any one of claims 6 to 10 or the polarizing plate according to claim 11 is laminated or arranged on the observation side of a flexible display unit. apparatus. Electroluminescence, wherein the antireflection film according to any one of claims 6 to 10 or the polarizing plate according to claim 11 is laminated or arranged on the observation side of a flexible display unit. Display device.

Images