JP2014013264A - Functional film for improving image quality and display device using the same - Google Patents

Abstract

An anti-reflection film with ultra-low reflectivity, which not only reduces reflected light that lowers visibility, but also reduces the occurrence of Nizimura and Newton rings in a display device. To provide a functional film for improving image quality having an effect of improving image quality.
An antireflection layer having a so-called moth-eye structure, in which microprotrusions are closely arranged on a transparent substrate 11, and an interval between the adjacent microprotrusions is equal to or less than a shortest wavelength of a wavelength band for antireflection. In the functional film 1 for improving image quality provided, the retardation of the transparent substrate 11 is set to 6000 nm or more.
[Selection] Figure 5

Description

  The present invention relates to a functional film for improving image quality and a display device using the functional film.

  In a display device that displays an image or the like on a monitor screen such as a television, a personal computer, or a smartphone, an antireflection film is generally disposed to reduce reflected light from the screen that reduces visibility. is there.

  As such an antireflection film, a method for preventing reflection by arranging a large number of minute protrusions in close contact with the surface of a transparent substrate (transparent film) has been proposed (see Patent Documents 1 to 3). This method utilizes the principle of a so-called moth-eye structure, and the refractive index for incident light is continuously changed in the thickness direction of the substrate, whereby a discontinuous interface of refractive index is obtained. Is eliminated to prevent reflection.

  In order to construct this antireflection film, a transparent substrate capable of transmitting light is required. As this transparent base material, triacetyl cellulose (TAC) having a low birefringence is used in order to reduce unevenness of different colors generated on the screen due to the birefringence of the base material (hereinafter also referred to as “Nizimura”). A film made of a cellulose ester represented by a typical method has been generally used. However, cellulose esters are generally expensive, and the problem of dimensional change and curling due to moisture absorption remains.

  On the other hand, as a base material for the functional film for improving the image quality to be arranged in the display device, a transparent resin capable of reducing Nizimura by using polyester film such as polyethylene terephthalate (PET) that can be manufactured at a lower cost instead of TAC. Attempts to use it as a substrate have been made (see Patent Document 4).

  However, in recent years, especially in a display device including a touch panel, not only mere jersey, but also a disturbance of an image called Newton ring that occurs when a finger pressure is applied to the screen has been regarded as a problem. About the problem of this Newton ring, there are many cases where it is inevitable in the structure of the display device, and even when the cellulose ester film or the polyester film disclosed in Patent Document 4 is used as the transparent resin base material, It cannot be prevented.

  On the other hand, it is often not desirable to arrange a new function enhancement layer in the situation surrounding recent display devices where the demand for cost reduction and the trend of thinning and miniaturization are progressing at the same time. The current situation is that no improvement means have been found.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 JP 2010-204630 A

  The present invention has been made in view of such a situation, and is an anti-reflection film with ultra-low reflectivity, which not only reduces reflected light that lowers visibility, but also at the same time Nizimura and Newton in display devices. An object of the present invention is to provide a functional film for improving image quality having an effect of improving the image quality of a display device even by reducing the occurrence of rings.

  The present inventor has conducted extensive research to solve the above-mentioned problems, and manufactured an antireflection film having a moth eye structure using a polyester film having a predetermined high retardation value. The idea has been reached and the present invention has been completed.

  Specifically, the present invention provides the following.

(1) In the functional film for improving image quality, in which microprotrusions are closely arranged on a resin substrate, and the interval between adjacent microprotrusions is equal to or less than the shortest wavelength of a wavelength band for preventing reflection,
The resin base material is a transparent base material having a retardation of 6000 nm or more.

  According to (1), the occurrence of azimuth in a display device in general can be suppressed to a high degree by the reflected light reduction effect and the transparent substrate having high retardation due to the moth-eye structure. Furthermore, by arranging this moth-eye structure under the touch panel, an effect of preventing Newton's ring in a touch panel type display device is also achieved.

  (2) In (1), conductive layers arranged in the same direction at a constant pitch are formed on at least one surface of the transparent substrate.

  According to (2), by providing the conductive layers arranged in the same direction at a constant pitch, the function film for improving image quality can also function as a sensor film of a touch panel. By disposing this on the touch panel display device, the factors that degrade the display quality of images, etc. in the touch panel display device, such as reflected light, Nizimura, and Newton rings, can be reduced without adding new members. Can do.

  (3) In (1) or (2), the transparent substrate has a refractive index (nx) in the slow axis direction which is the direction having the largest refractive index in the plane, and a direction orthogonal to the slow axis direction. The difference (nx−ny) from the refractive index (ny) in the fast axis direction is 0.05 or more.

  According to (3), generation | occurrence | production of the wiggle of a display apparatus can be suppressed more highly. In addition, the above-mentioned predetermined retardation value can be obtained within a preferable film thickness range without unnecessarily increasing the film thickness of the transparent substrate.

  (4) In any one of (1) to (3), the transparent base material is a polyester resin, a polyolefin resin, a (meth) acrylic resin, a polyurethane resin, a polyethersulfone resin, or a polycarbonate resin. , A polysulfone resin, a polyether resin, a polyether ketone resin, a (meth) acrylonitrile resin, and a cycloolefin resin.

  According to (4), while maintaining the preferable light transmittance of the transparent base material, the above-mentioned predetermined retardation value can be obtained, and the occurrence of nitrite can be sufficiently suppressed.

  (5) In any one of (1) to (4), the transparent substrate is polyethylene terephthalate.

  According to (5), while maintaining the preferable light transmittance of a transparent base material, a more preferable retardation value can be obtained and generation | occurrence | production of a nidimla can be suppressed further highly. In addition, since polyethylene terephthalate is excellent in heat resistance, the range of selection of heating conditions accompanying the production and processing of a functional film for improving image quality is widened.

  (6) The display device includes the functional film for improving image quality according to any one of (1) to (5), a touch panel unit, and an image display panel.

  According to (6), it is possible to provide a display device in which factors such as reflected light, Nizimura, and Newton rings that reduce display quality of images and the like are reduced.

  (7) In (6), a polarizing plate is provided on a light exit surface side of the image display panel, and the image display panel is a liquid crystal panel.

  According to (7), it is possible to provide a liquid crystal display device in which factors such as reflected light, Nizimura, and Newton rings that reduce display quality of images and the like are reduced.

  (8) In (7), the angle formed by the absorption axis of the polarizing plate and the slow axis of the transparent substrate of the functional film for improving image quality is 0 ° ± 30 ° or 90 ° ± 30 °. It is arranged to become.

  According to (8), it is possible to provide a display device capable of extremely highly suppressing the occurrence of nitrile in the display image.

  (9) In (7) or (8), the functional film for improving image quality is laminated on the surface of the polarizing plate on the touch panel unit side.

  According to (9), the effect of preventing the occurrence of Newton rings becomes significant.

  (10) In (7) or (8), the functional film for improving image quality is laminated on the back side of the touch panel unit.

  According to (10), by laminating a functional film for improving image quality directly on the touch panel unit, the antireflection effect on the touch panel screen and the Newton ring prevention effect are improved in a balanced manner, and at the same time, in particular, the conductive layer By using a functional film for improving image quality comprising the above, it is possible to use the functional film for improving image quality as a sensor film for a touch panel, whereby the required performance can be obtained with a simpler layer configuration.

  (11) In any one of (6) to (10), the functional film for improving image quality is laminated on the surface side of the touch panel unit.

  According to (11), the antireflection effect by the microprojection layer 12 on the touch panel screen can be most effectively exhibited, and the visibility of the image or the like of the touch panel device 10 can be significantly improved.

  Since the present invention is composed of the above-described configuration, it is an ultra-low-reflective functional film for improving image quality, and not only reduces reflected light that lowers visibility, but at the same time, Even by reducing the occurrence of Newton's rings, it is possible to provide a functional film for improving image quality that has the effect of improving the image quality of the display device.

It is a perspective view which shows typically the functional film for image quality improvement which is one Example of this invention. It is sectional drawing which shows typically the functional film for image quality improvement provided with the electrode which is the other Example of this invention. It is a figure which shows the manufacturing process of the functional film for image quality improvement of FIG. It is a figure which shows the roll plate which concerns on the functional film for image quality improvement of FIG. It is sectional drawing which shows typically a touchscreen apparatus provided with the functional film for image quality improvement of this invention. It is sectional drawing which shows typically an example of arrangement | positioning in the touchscreen apparatus of the functional film for image quality improvement of this invention. It is a figure explaining the measuring method of an average orientation angle and an orientation angle difference.

  The present invention is described in detail below. In the present specification, unless otherwise specified, curable resin precursors such as monomers, oligomers, and prepolymers are also referred to as “resins”. In each drawing, the ratio of the vertical and horizontal scales is increased or decreased from the actual size for convenience of explanation.

<Functional Film for Improving Image Quality (First Embodiment)>
FIG. 1 is a diagram (conceptual perspective view) showing a functional film 1 for improving image quality according to the first embodiment of the present invention. The functional film 1 for improving image quality is a functional film whose overall shape is formed by a film shape. The functional film for improving image quality is not limited to a flat film shape, but a flat sheet shape and a flat plate shape (referred to as a film, a sheet, and a plate in order of relatively small thickness). Also, instead of a flat shape, a curved shape, a three-dimensional film shape, a sheet shape, or a plate shape can be used, and an appropriate shape can be appropriately employed depending on the application. .

  As shown in FIG. 1, the functional film 1 for improving image quality includes a transparent substrate 11 and a microprojection layer 12 composed of a large number of microprojections arranged in close contact with the surface of the transparent substrate 11.

  The transparent substrate 11 has a retardation of 6000 nm or more, preferably 10,000 nm or more. If the retardation is less than 6000 nm, the display image of the display device will be distorted. On the other hand, the upper limit of the retardation of the transparent substrate is not particularly limited, but is preferably about 30000 nm, and more preferably about 20000 nm. If the thickness exceeds 30000 nm, no further improvement in the effect of improving the display image is observed, and the film thickness becomes considerably thick.

  The retardation is the refractive index (nx) in the direction with the highest refractive index (slow axis direction) in the plane of the transparent substrate, and the refraction in the direction (fast axis direction) perpendicular to the slow axis direction. The ratio (ny) and the thickness (d) of the transparent substrate are represented by the following formula (Equation 1).

(Equation 1)
Retardation (Re) = (nx−ny) × d

    The retardation can be measured, for example, by KOBRA-WR manufactured by Oji Scientific Instruments (measurement angle 0 °, measurement wavelength 548.2 nm).

  In the present invention, the nx-ny (hereinafter also referred to as Δn) is preferably 0.05 or more. If the above Δn is less than 0.05, there may be a case where a sufficient effect of suppressing azimuth cannot be obtained. Moreover, since the film thickness required in order to obtain the retardation value mentioned above becomes thick, it is not preferable. A more preferable lower limit of the Δn is 0.07.

  The material constituting the transparent substrate 11 is not particularly limited as long as it satisfies the above-mentioned retardation. For example, polyester resin, polyolefin resin, (meth) acrylic resin, polyurethane resin, polyether sal One type selected from the group consisting of a phon resin, a polycarbonate resin, a polysulfone resin, a polyether resin, a polyether ketone resin, a (meth) acrylonitrile resin, and a cycloolefin resin is preferably used. It is done.

  The transparent substrate 11 is particularly preferably made of polyethylene terephthalate (PET). This is because polyethylene terephthalate is highly versatile and easily available. Also, PET is excellent in light transmittance, heat or mechanical properties, can be controlled by stretching, has a large intrinsic birefringence, and can easily obtain a large retardation even when the film thickness is small. It is.

  Furthermore, since PET has a small heat shrinkage ratio due to heating, there are few restrictions on heating conditions during processing. Therefore, it is also preferable in that the degree of freedom in selecting the method for producing the functional film 1 for improving image quality can be increased. For example, when the conductive layer 13 is formed, a printing process using a thermosetting resin as a binder can be employed under a wide range of heating conditions. Thereby, the selection for forming the conductive layer 13 having excellent conductive performance at a lower cost becomes possible.

  The method for obtaining the transparent substrate 11 is not particularly limited as long as the above-described retardation is satisfied. For example, when the material is polyester such as PET, unstretched polyester formed by melt extrusion of the material polyester. A method of performing heat treatment after transverse stretching using a tenter or the like at a temperature equal to or higher than the glass transition temperature. The transverse stretching temperature is preferably 80 to 130 ° C, more preferably 90 to 120 ° C. The transverse draw ratio is preferably 2.5 to 6.0 times, more preferably 3.0 to 5.5 times. When the transverse draw ratio exceeds 6.0 times, the light transmittance of the transparent base material 11 made of the polyester is likely to be lowered. When the draw ratio is less than 2.5 times, the draw tension is also reduced. In some cases, the birefringence of the obtained transparent substrate 11 becomes small, and the retardation cannot be made 6000 nm or more.

  In the present invention, the unstretched polyester is subjected to transverse stretching under the above conditions using a biaxial stretching test apparatus, and then stretched in the flow direction with respect to the transverse stretching (hereinafter also referred to as “longitudinal stretching”). You may go. In this case, the longitudinal stretching preferably has a stretching ratio of 2 times or less. When the draw ratio of the above-mentioned longitudinal stretching exceeds twice, the value of Δn may not be within the preferred range described above. The treatment temperature during the heat treatment is preferably 100 to 250 ° C, more preferably 180 to 245 ° C.

  Examples of the method for controlling the retardation of the transparent substrate 11 formed by the above-described method to 6000 nm or more include a method of appropriately setting the stretching ratio, the stretching temperature, and the film thickness of the transparent substrate to be formed. Specifically, for example, the higher the stretching ratio, the lower the stretching temperature, and the thicker the film, the easier it is to obtain high retardation. The lower the stretching ratio, the higher the stretching temperature, and the film thickness. The thinner, the easier it is to obtain low retardation.

  The thickness of the transparent substrate 11 is appropriately determined according to the constituent material and the like, but is preferably in the range of 20 to 500 μm. If the thickness is less than 20 μm, the retardation of the transparent substrate 11 may not be 6000 nm or more, and the anisotropy of mechanical properties becomes remarkable, and tearing, tearing, etc. are likely to occur, and the practicality as an industrial material is remarkable. May decrease. On the other hand, if it exceeds 500 μm, the transparent substrate is very rigid, the flexibility specific to the polymer film is lowered, and the practicality as an industrial material is also lowered, which is not preferable. A more preferable lower limit of the thickness of the transparent substrate 11 is 30 μm, a more preferable upper limit is 400 μm, and an even more preferable upper limit is 300 μm.

  The transparent substrate 11 preferably has a transmittance in the visible light region of 80% or more, and more preferably 84% or more. In addition, the said transmittance | permeability can be measured by JISK7361-1 (The test method of the total light transmittance of a plastic-transparent material).

  Next, the microprojection layer 12 composed of a large number of microprojections will be described. The microprojection layer 12 is formed on the surface of the transparent substrate 11 with an ultraviolet curable resin, which is a molding resin used for forming a micro uneven shape, using a mold for molding. . The functional film 1 for improving image quality is formed so that the refractive index gradually changes in the thickness direction due to the uneven shape of the microprojection layer 12, and reduces the reflection of incident light in a wide wavelength range by the principle of the moth-eye structure.

  In addition, each microprotrusion of the microprotrusion layer 12 formed on the surface of the transparent substrate 11 thereby has an interval d between adjacent microprotrusions that is equal to or less than the shortest wavelength λmin (d ≦ λmin) of the wavelength band for preventing reflection. Are closely arranged. For example, in order to improve visibility by arranging the image display device panel, the shortest wavelength is set to the shortest wavelength (380 nm) in the visible light region in consideration of individual differences and viewing conditions, and the interval d varies. In consideration of the thickness, it is set to 100 to 300 nm. The adjacent minute protrusions related to the distance d are so-called adjacent minute protrusions, which are in contact with the hem portion of the minute protrusion, which is the base portion on the transparent substrate 11 side. When the microprojection layer 12 is formed so that the microprojections are closely arranged so that a line segment is created so as to sequentially follow the valleys between the microprojections, a large number of polygonal regions surrounding each microprojection are obtained in plan view. A net-like pattern formed by connection is formed. The adjacent minute protrusions related to the distance d are protrusions that share a part of the line segments constituting the mesh pattern.

  The minute protrusions are defined in more detail as follows. In the antireflection by the moth-eye structure, the effective refractive index at the interface between the transparent substrate surface and the adjacent medium is continuously changed in the thickness direction to prevent reflection. It is necessary to satisfy the following conditions. With respect to the protrusion spacing, which is one of these conditions, when the minute protrusions are regularly arranged at a constant period, as disclosed in, for example, Japanese Patent Application Laid-Open No. 50-70040 and Japanese Patent No. 4632589, they are adjacent to each other. The interval d between the minute protrusions is a period P (d = P) of the protrusion arrangement. As a result, when the longest wavelength in the visible light band is λmax and the shortest wavelength is λmin, the minimum necessary condition that can exhibit an antireflection effect at the longest wavelength is P ≦ λmax. Necessary and sufficient conditions capable of exhibiting the antireflection effect with respect to the wavelength are P ≦ λmin.

  The wavelengths λmax and λmin may have some width depending on observation conditions, light intensity (luminance), individual differences, and the like, but are typically λmax = 780 nm and λmin = 380 nm. A preferable condition that can more reliably exhibit the antireflection effect for all wavelengths in the visible light band is d ≦ 300 nm, and a more preferable condition is d ≦ 200 nm. Note that the lower limit value of the period d is usually d ≧ 50 nm, preferably d ≧ 100 nm, for reasons such as the expression of the antireflection effect and ensuring the isotropic (low angle dependency) of the reflectance. On the other hand, the height H of the protrusion is set to H ≧ 0.2 × λmax = 156 nm (assuming λmax = 780 nm) from the viewpoint of exhibiting a sufficient antireflection effect.

<Functional Film for Improving Image Quality (Second Embodiment)>
Next, a functional film for improving image quality provided with a conductive layer according to a second embodiment of the present invention will be described. FIG. 4 is a diagram (conceptual perspective view) showing a functional film 1A for improving image quality provided with a conductive layer. The functional film 1A for improving image quality is characterized in that a conductive layer 13 (13a, 13b) is formed on at least one surface of the transparent substrate 11, and the other configurations are the images according to the first embodiment. This is a functional film having the same configuration as the functional film 1 for improving quality. Hereinafter, regarding the functional film 1A for improving image quality, the description of the same components as those of the functional film 1 for improving image quality of the first embodiment will be omitted, and the structure of the conductive layer 13 will be mainly described.

  In the functional film 1A for improving image quality, the conductive layer 13 is formed on at least one surface of the transparent substrate 11. Further, as shown in FIG. 4, conductive layers 13 a and 13 b may be formed on both surfaces of the transparent substrate 11, respectively.

  The pattern shape of the conductive layer 13 in plan view is preferably a stripe shape (parallel line group or stripe pattern) arranged in the same direction at a constant pitch. By providing the stripe-shaped (parallel line group thru | or stripe pattern) -shaped conductive layer 13, the functional film 1A for image quality improvement can be used very suitably for a touch panel type display device. That is, the functional film 1A for improving image quality provided with such a stripe-shaped conductive layer 13 can also exhibit a function as a touch panel sensor film by being appropriately disposed in the touch panel unit. Specifically, as shown in FIG. 4, the conductive layer 13 a is formed in one direction (x direction) on one surface of the transparent substrate 11, and the direction orthogonal to the conductive layer 13 a on the other surface (y Direction) and two image quality improving functional films 1A each having a stripe-shaped conductive layer 13 are stacked so that the directions of the conductive layer 13 are orthogonal to each other in plan view. Can also be used as a touch panel sensor film. Thereby, in addition to antireflection, it is possible to prevent Nizimura and Newton ring, and it is possible to improve the visibility of the display device without adding a new member to the touch panel unit.

  In addition, the pattern shape of the conductive layer 13 may be a mesh (mesh or lattice) shape, a spiral shape, or the like. Further, for the purpose of reducing moire, a random mesh pattern or a pseudo-random mesh pattern can be used.

  Regarding the pattern shape of the conductive layer 13, for example, the line width and the line pitch can be 5 to 50 μm, and the line pitch can be 100 to 500 μm. The aperture ratio (ratio of the total area of the openings in the total area of the predetermined pattern) is usually about 50 to 95%. In addition to the predetermined pattern, there may be a ground pattern such as all solids (no openings) adjacent to the periphery of the peripheral part or a part of the peripheral part while maintaining electrical continuity therewith. Incidentally, the line width is required to be further refined in order to obtain a more highly transparent line. From this viewpoint, it is preferably 30 μm or less, particularly 20 μm or less.

  The thickness of the conductive layer 13 varies depending on the resistance value provided in the conductive layer 13, but at the center portion (the top portion of the projection pattern) due to the balance between the conductive performance and the suitability of adhesion of other members onto the conductive layer 13. In the measurement, it is usually 2 μm or more and 50 μm or less, preferably 5 μm or more and 20 μm or less.

  The conductive layer 13 may be a pattern obtained by patterning a transparent conductive material layer formed on the transparent substrate 11, or may be formed by patterning an opaque metal layer and appearing transparent due to the presence of an opening. Further, when the function similar to the pattern can be replaced by the main circuit side, it may be a set of fine rectangular frame shapes having mere invisibility regardless of the pattern shape.

  As the transparent conductive material, ITO, silver nanowire, carbon nanotube, conductive polymer, or the like can be used.

  As the opaque metal layer, any conductive metal can be used, and silver, copper, gold, aluminum, and the like are preferably used. The metal layer may be a single metal or alloy, or may be one in which metal particles are bound by a binder. Further, blackening treatment or rust prevention treatment is applied to the metal surface as necessary.

  As a pattern forming method for the conductive layer 13, pattern printing, photolithography (etching), transfer, self-organization, and the like are applicable. From the viewpoint of improving cost performance, the functional film 1 for improving image quality is particularly preferably formed by pattern printing. Pattern printing methods include a method of printing a conductive composition in a predetermined pattern, a method of printing a material having a catalytic function of electroless plating on a predetermined pattern, and electroless plating of a conductive metal, and electroless plating. Examples include a method of adding a catalyst and performing electroless plating after printing a material forming the catalyst and the adduct.

  Any method can be applied as the pattern printing method depending on the required pattern accuracy, but screen printing, intaglio offset printing, or a method of transferring from the intaglio using a UV curing primer is preferably used.

  When patterning the conductive layer 13 with a conductive composition containing metal particles and a binder resin by pattern printing, the metal particles can be used as long as they are conductive metals, as exemplified above. The conductive layer 13 may be a single metal or alloy, or may be formed by binding metal particles with a binder. As the binder resin, any of thermosetting resins, ionizing radiation curable resins, and thermoplastic resins can be used. In addition, when performing the below-mentioned electrical resistance reduction process, the water-insoluble resin which does not melt | dissolve with an acid or warm water is used.

  Examples of binder resins that can be used for pattern printing include thermosetting resins such as melamine resins, polyester-melamine resins, epoxy-melamine resins, phenol resins, polyimide resins, thermosetting acrylic resins, thermosetting resins. Examples of the resin include polyurethane resins and thermosetting polyester resins. Examples of the ionizing radiation curable resin include those described later as a primer material. These may be used alone or in combination of two or more. And use. Examples of the thermoplastic resin include thermoplastic polyester resins, polyvinyl butyral resins, thermoplastic acrylic resins, thermoplastic polyurethane resins, vinyl chloride-vinyl acetate copolymers, and the like. A mixture of two or more types is used. In addition, when using a thermosetting resin, you may add a curing catalyst as needed. When an ultraviolet (or visible light) curable ionizing radiation curable resin is used, a photopolymerization initiator may be added as necessary. Further, in order to obtain fluidity suitable for filling the concave portion of the plate, these resins are usually used as a varnish dissolved in a solvent. There is no particular limitation on the type of solvent used as the conductive paste, and it can be used by appropriately selecting from the solvents generally used for printing inks. However, when a primer layer is provided, the stable hardening of the primer layer is inhibited. And those that do not swell, whiten or dissolve the cured primer layer. The content of the solvent is usually about 10 to 70% by mass, but is preferably as small as possible within a range where necessary fluidity can be obtained. In addition, when an ionizing radiation curable resin is used, it does not necessarily require a solvent because it is inherently fluid.

  In the functional film 1 for improving image quality, a primer layer (not shown) may be provided between the transparent substrate 11 and the conductive layer 13 in order to improve the adhesion between the transparent substrate 11 and the conductive layer 13. preferable. The primer layer has good adhesion to both the transparent base material 11 and the conductive layer 13, and is a transparent layer for ensuring light transmission of the opening (conductive pattern layer non-formed part). Further, when the conductive layer 13 is formed by a specific intaglio printing method as described later, the primer layer is provided on the transparent substrate 11 in a state where fluidity can be maintained, and is in contact with the intaglio at the time of intaglio printing. During this time, the layer is formed as a layer to be solidified from the liquid state, and is a layer solidified when the final conductive layer 13 is formed.

  In the functional film 1 for improving image quality, other layers may be appropriately formed or processed as necessary. For example, when the durability against rust is insufficient, a rust prevention layer may be provided. The rust preventive layer can be provided by a conventionally known material and method.

<Method for producing functional film for improving image quality>
Hereinafter, a preferable embodiment of the method for producing the functional film 1 for improving image quality according to the first embodiment of the present invention and the functional film 1A for improving image quality according to the second embodiment will be described.

  First, the manufacturing method of the functional film 1 for improving image quality according to the first embodiment of the present invention will be described. In the production of the functional film 1 for improving image quality, a transparent base material forming step for obtaining a transparent base material 11 by forming a base resin into a film shape, and a micro projection layer 12 on the transparent base material 11 are formed. A protruding layer forming step is performed. Prior to the microprojection forming step, it is necessary to manufacture the roll plate 102 which is a mold for molding, and the steps for performing it will also be described.

[Transparent substrate forming step]
In this step, first, a material resin such as polyethylene terephthalate is melted, and an unstretched film is formed by a known extrusion method. Then, the unstretched film is stretched sequentially at different magnifications in the X and Y directions by a biaxial stretching test apparatus. About each draw ratio, what is necessary is just to adjust suitably in the range demonstrated above. By the above operation, the transparent substrate 11 having a retardation of 6000 nm or more can be obtained.

[Microprojection layer forming process]
FIG. 2 is a diagram showing a process of forming the fine protrusion layer 12 on the functional film 1 for improving image quality. In the manufacturing process 100, in the resin supply process, the ultraviolet curable resin 120 is applied to the substrate 110 in the form of a belt-shaped film by the die 101. The application of the ultraviolet curable resin 120 is not limited to the case using the die 101, and various methods can be applied. Subsequently, in this manufacturing process 100, the pressing roller 103 presses and presses the substrate 110 on the peripheral side surface of the roll plate 102 which is a mold for forming an image quality improving functional film, whereby the substrate 110 is acrylated. The ultraviolet curable resin 120 of the system is brought into close contact, and the ultraviolet curable resin 120 is sufficiently filled in a concave portion having a minute concavo-convex shape formed on the peripheral side surface of the roll plate 102. In this state, the manufacturing process cures the ultraviolet curable resin 120 by irradiating with ultraviolet rays, thereby forming minute protrusions on the surface of the substrate 110. In this manufacturing process, the substrate 110 is subsequently peeled off from the roll plate 102 via the peeling roller 104 together with the cured ultraviolet curable resin 120. In the manufacturing process 100, an adhesive layer or the like is formed on the substrate 110 as necessary, and then cut into a desired size to create the functional film 1 for improving image quality. As a result, the functional film 1 for improving the image quality can be efficiently molded by sequentially molding the minute shape formed on the peripheral side surface of the roll plate 102 which is a mold for molding on a long base material 110 made of a roll material. Mass production.

  FIG. 3 is a perspective view showing the configuration of the roll plate 102. The roll plate 102 is formed with minute irregularities on the peripheral side surface of the base material, which is a cylindrical metal material, by repeating anodization and etching, and the minute irregularities are formed on the substrate 110 as described above. It is shaped. For this reason, a columnar or cylindrical member in which a high-purity aluminum layer is provided at least on the peripheral side surface is used as the base material. More specifically, in this embodiment, a stainless steel pipe is applied to the base material, and a high-purity aluminum layer is provided directly or via various intermediate layers. In addition, it may replace with a stainless steel pipe and may apply pipe materials, such as copper and aluminum. The roll plate 102 is formed such that minute holes are densely formed on the peripheral side surface of the base material by repeating the anodizing treatment and the etching treatment, and the diameter of the roll plate 102 becomes larger as it approaches the opening. An uneven shape is formed by gradually increasing the diameter of the minute holes. As a result, the roll plate 102 is densely formed with minute holes that gradually decrease in diameter in the depth direction, and the functional film 1 for improving image quality has minute irregularities due to minute protrusions corresponding to the minute holes. Then, the microprojection layer 12 is formed.

[Anodic oxidation treatment, etching treatment]
The roll plate 102 can be manufactured by the following steps. In the manufacture of the roll plate 102, first, the peripheral side surface of the base material is made into a super mirror surface by an electrolytic composite polishing method that combines electrolytic elution action and abrasion action by abrasive grains (electrolytic polishing). Subsequently, aluminum is sputtered on the peripheral side surface of the base material to form a high-purity aluminum layer. Subsequently, the base material is processed by alternately repeating the anodizing step and the etching step a plurality of times, and the roll plate 102 is formed.

  In the anodizing step, a minute hole is formed on the peripheral side surface of the base material by an anodic oxidation method, and the formed minute hole is further dug. Here, in the anodic oxidation step, various methods applied to the anodic oxidation of aluminum can be widely applied, for example, when a carbon rod, a stainless steel plate, or the like is used for the negative electrode. Moreover, various neutral and acidic solution can also be used also about a solution, More specifically, sulfuric acid aqueous solution, oxalic acid aqueous solution, phosphoric acid aqueous solution etc. can be used, for example. In this anodizing step, minute holes are formed into shapes corresponding to target depths and minute protrusion shapes, respectively, by managing the liquid temperature, the voltage to be applied, the time for anodizing, and the like.

  In the subsequent etching process, the mold is immersed in an etching solution, the hole diameter of the minute hole formed and dug through the anodizing process is expanded by etching, and the hole diameter is gradually and gradually reduced in the depth direction. These small holes are shaped to be small. As the etching solution, various etching solutions applied to this type of treatment can be widely applied. More specifically, for example, an aqueous sulfuric acid solution, an aqueous oxalic acid solution, an aqueous phosphoric acid solution, or the like can be used. . Accordingly, in this manufacturing process, the anodizing process and the etching process are alternately performed a plurality of times, thereby forming micro holes for shaping on the peripheral side surface of the base material.

  As described above, the functional film 1 for improving image quality according to the first embodiment of the present invention can be manufactured. Then, the functional film 1 A for improving image quality according to the second embodiment of the present invention is manufactured by further forming a conductive layer 13 on the functional film 1 for improving image quality by a conductive layer forming step described below. can do.

[Conductive layer forming step]
In this step, the conductive layer 13 is formed on one surface of the transparent substrate 11 using a conductive composition (conductive paste) containing metal particles and a binder resin.

  The predetermined pattern of the conductive layer 13 can be formed by various known printing methods such as silk screen printing, flexographic printing, and offset printing.

  Moreover, in order to improve the adhesiveness of the transparent base material 11 and the conductive layer 13, when providing a primer layer between the transparent base material 11 and the conductive layer 13, as a manufacturing method of the said conductive member, for example, Intaglio printing using a specific primer described in a published patent document (WO2008 / 149969 pamphlet) is recommended. The outline of this intaglio printing method will be described below.

  In the intaglio printing method, after applying a conductive composition to a plate surface formed in a predetermined pattern, the conductive composition adhering to other than the inside of the concave portion is scraped to fill the concave portion with the conductive composition. The transparent base material 11 having a liquid primer layer already formed on one side thereof is pressure-bonded in such a direction that the primer layer is in contact with the intaglio, and the conductive composition in the recess and the primer layer are brought into close contact with each other without any gap. After solidifying the primer layer from a liquid state to a solid state, the transparent substrate 11 is separated from the intaglio to release the plate, thereby transferring the conductive composition onto the solidified primer layer on the transparent substrate and printing. Is.

A conductive member in which the conductive layer 13 is formed on the transparent substrate 11 can be obtained by such intaglio printing. This conductive member is further treated (i) in the presence of moisture as a hot water treatment and at a relatively high temperature, and / or (ii) in contact with an acid as an acid treatment, thereby forming the conductive layer 13. The volume resistivity and the surface resistivity are reduced, and the conductive performance is improved.
The hot water treatment (i) is performed by immersing the conductive member in hot water having a water temperature of 30 to 100 ° C., flowing hot water over the conductive member, or in an atmosphere having a relative humidity of 60% or more at an air temperature of 30 to 100 ° C. The method of exposing to is preferable, and the treatment time is about 5 minutes to 20 seconds.
In the acid treatment of (ii), the acid is not particularly limited and can be selected from various inorganic acids and organic acids, but is preferably hydrochloric acid, sulfuric acid, citric acid or an aqueous solution thereof, and the treatment time with the acid is several minutes. The following is sufficient, and the processing temperature is sufficient at room temperature. The method of treating with an acid is not particularly limited, but the method of immersing in an acid solution is preferable because of its excellent conductivity improving effect, and the acid concentration is preferably 1 mol / L or less, more preferably 0.1 mol / L. L or more.
Among these electrical resistance reduction treatments, it is preferable to perform the hot water treatment (i) subsequently after the acid treatment (ii) from the viewpoint of the electrical resistance reduction effect and workability.
By this electrical resistance reduction treatment, the surface resistivity of the entire conductive pattern layer is reduced to about 80 to 30% before the treatment (the apparent volume resistivity is also about 80 to 30% before the treatment).

  The conductive layer 13 can also be formed by a method of patterning a metal foil by an etching process. In this case, a copper foil can be preferably used as the metal foil. As a specific manufacturing method, after a copper foil is dry-laminated on a transparent substrate 11 through a primer layer to form a continuous strip-shaped copper foil laminated sheet, photolithography is performed on the copper foil of the copper foil laminated sheet. The conductive layer 13 can be formed by performing a chemical etching process using a method.

<Touch panel type display device>
Next, the touch panel device 10 in which the functional film 1 for improving image quality is arranged will be described with reference to FIGS. The touch panel device of the present invention includes the functional film 1 for improving image quality, the touch panel unit, and the image display panel as essential constituent elements, and other constituent members are not necessarily essential, but are preferably one below. As an embodiment, a functional film 1 for improving image quality, a liquid crystal panel unit 4 as an image display panel, and a touch panel device 10 including other constituent members will be described.

  As shown in FIG. 5, the touch panel device 10 includes a touch panel unit 2, an image quality improving functional film 1 </ b> A, an image quality improving functional film 1, in order from the upper surface side on which the user recognizes an image or the like. A polarizing plate 3 and a liquid crystal panel unit 4 are stacked in this order, and a backlight 5 is disposed below the liquid crystal panel unit 4. However, the lamination position of the image quality improvement functional film 1 is not limited to this, and for example, as another arrangement mode, it may be arranged on the upper surface side of the touch panel unit 2 as shown in FIG.

  In addition, the touch panel device 10 is a single layer and / or multiple layers having any other function as long as the image quality improvement performance of the functional film 1 for improving image quality and the display function of the touch panel device 10 are not impaired. The formed structure may be sufficient. The optional layer is not particularly limited, and examples thereof include a hard coat layer, an antistatic layer, a low refractive layer, a high refractive index layer, an antiglare layer, an antifouling layer, an antireflection layer, a high dielectric layer, and an electromagnetic wave shielding layer. And an adhesive layer.

  In the touch panel device 10, the functional film 1 for improving image quality is arranged in a single layer or two layers on an arbitrary surface between the surface of the touch panel unit 2 and the upper surface of the polarizing plate 3 (surface on the touch panel unit side).

  When laminating the functional film for improving image quality on the back surface of the touch panel unit 2, the functional film for improving image quality 1 </ b> A is arranged by placing the functional film for improving image quality 1 </ b> A provided with the conductive layer 13 here. It can be used as a film sensor film for a touch panel while maintaining the effect of improving the quality. In addition, as shown in FIG. 5, an image quality improving functional film 1 and an image quality improving functional film 1 </ b> A may be laminated on both the upper surface of the polarizing plate 3 and the back surface of the touch panel unit 2, respectively.

  When the functional film 1 for improving image quality is disposed below the touch panel unit 2, the rapid refraction of incident light due to the distortion of the interface shape between layers formed by the pressure from the touch panel surface side is minute. Since the projection layer 12 relaxes and prevents reflection near the interface, the occurrence of Newton rings due to pressure from the touch panel surface side can be suppressed.

  Moreover, when the functional film 1 for image quality improvement is laminated | stacked on the upper surface (surface by the side of a touch panel unit) of the polarizing plate 3, it is preferable at the point which the generation | occurrence | production prevention effect of a Newton ring is remarkable. “The functional film 1 for improving image quality is laminated on the upper surface of the polarizing plate 3” means, for example, other layers not shown between the touch panel unit 2 and the polarizing plate 3 in FIG. In the case where the image quality improving functional film 1 is disposed, the image quality improving functional film 1 is laminated directly on the polarizing plate 3 without the other layers.

  Further, when the functional film 1 for improving image quality is laminated on the back side of the touch panel unit, it is easy to achieve an effective antireflection effect in the touch panel unit 2, and the image quality improving function including the conductive layer 13 in particular. By using the film 1A, it can also be used as a sensor film for a touch panel.

  Further, when the image quality improving functional films 1 and 1A are laminated on both the upper surface of the polarizing plate 3 and the back surface of the touch panel unit 2, respectively, as shown in FIG. The manifestation of the prevention effect is particularly remarkable.

  When the functional film 1 for improving image quality is laminated on the upper surface of the touch panel unit 2 as shown in FIG. 6, the antireflection effect by the fine protrusion layer 12 is most effectively exhibited, and the touch panel device 10. The visibility of the image and the like can be significantly improved.

  In the functional film 1 for improving image quality, in the touch panel device 10, the angle formed between the slow axis of each transparent substrate 11 and the absorption axis of the polarizing plate 3 described in detail below is 0 ° ± 30 ° or It arrange | positions so that it may become 90 degrees +/- 30 degrees. When the angle formed by the slow axis of the transparent substrate 11 and the absorption axis of the polarizing plate 3 is within the above range, it is possible to extremely highly prevent the occurrence of nitridation in the display image of the touch panel device 10. The reason for this is not clear, but is thought to be due to the following reasons.

  That is, in an environment where there is no external light or fluorescent light (hereinafter, such an environment is also referred to as “dark place”), the retardation of the transparent base material is set to 6000 nm or more, whereby the touch panel device 10 can display an image. The occurrence of azimuth irregularities can be suppressed regardless of the angle between the slow axis of the transparent substrate 11 of the functional film for improving quality 1 and the absorption axis of the polarizing plate 3. However, in an environment where there is ambient light or fluorescent light (hereinafter, this environment is also referred to as “light”), external light and fluorescent light have only a continuous wide spectrum. Therefore, if the angle formed by the slow axis of the transparent substrate 11 and the absorption axis of the polarizing plate 3 is not within the above-described range, azimuth is generated and display quality is deteriorated. Furthermore, since the light of the backlight 5 transmitted through the color filter 43 is not limited to the light having a continuous wide spectrum, the angle formed by the slow axis of the transparent substrate 11 and the absorption axis of the polarizing plate 3 is set as described above. If it is not within the range, it is presumed that the discoloration will occur and the display quality will deteriorate. In the case where a plurality of image quality improving functional films 1 are laminated in the touch panel device 10 or when a transparent base material is further laminated on the outermost surface as a protective film, all the layers fall within the above angle range. Is preferred.

  Here, the transmittance of light transmitted through the two polarizing plates placed in the crossed Nicols state is expressed by the following equation (Equation 2). In the following equation 1, I / I0 represents the transmittance of light transmitted through two polarizing plates placed in the crossed Nicols state, and I represents the two polarizing plates placed in the crossed Nicols state. The intensity of transmitted light, I0, indicates the intensity of light incident on two polarizing plates placed in a crossed Nicols state.

(Equation 2)
I / I0 = sin22θ · sin2 (πRe / λ)

  Further, the transmittance of light transmitted between the polarizing plates when the polarizing plates are arranged at a certain angle θ with respect to the polarizing plates arranged in crossed Nicols is expressed by the following formula (Equation 3). In Equation 2, I represents the intensity of light transmitted between polarizing plates arranged in crossed Nicols, and I0 represents the intensity of light incident between polarizing plates arranged in crossed Nicols. In this case, when the angle (θ) made by the direction of the slow axis of the transparent substrate 11 with respect to the absorption axis of the polarizing plate 3 is 45 °, the light transmittance is maximum, but the transmittance is Since it changes depending on the retardation of the transparent substrate 11 and the wavelength of transmitted light, an interference color (such as Nizimura) peculiar to the retardation value is observed. Here, when the angle (θ) is set to 0 ° or 90 °, the light transmittance is zero, so that no interference color is observed.

(Equation 3)
I / I0 = sin22θ · sin2 (πRe / λ)

  In addition, said orientation angle difference is calculated | required as a value which subtracted the minimum value from the maximum value of the orientation angle measured, for example using the molecular orientation meter (MOA; Molecular Orientation Analyzer) by Oji Scientific Instruments. Moreover, said slow axis direction is a direction of the average orientation angle | corner of the slow axis direction of the said polarizing plate protective film calculated | required using the said molecular orientation meter (MOA; Molecular Orientation Analyzer).

  As the touch panel unit 2, a known touch panel unit can be used. Generally, the touch panel unit has a configuration in which a sensor film in which a conductive pattern in the x direction or a conductive pattern in the y direction is formed on a film such as PET is sequentially laminated on a glass plate. This can also be used in the present invention. However, the touch panel unit 2 of this example is used as a sensor film by disposing an image quality improving functional film 1 </ b> A including the conductive layer 13 on the lower surface of the touch panel unit 2. The touch panel unit 2 may have a configuration in which other arbitrary layers are formed as a single layer and / or multiple layers. The optional layer is not particularly limited, and examples thereof include a hard coat layer, an antistatic layer, a low refractive layer, a high refractive index layer, an antiglare layer, an antifouling layer, an antireflection layer, a high dielectric layer, and an adhesive layer. Etc.

  The polarizing plate 3 is not particularly limited as long as it has desired polarization characteristics, and those generally used for a polarizing plate of a liquid crystal display device can be used. Specifically, for example, a polyvinyl alcohol film is stretched, and a polarizing plate containing iodine is preferably used.

  The liquid crystal panel unit 4 is not particularly limited, and generally known liquid crystal panel units for liquid crystal display devices can be used. For example, as shown in FIG. 1, a liquid crystal panel unit 4 having a general structure in which a liquid crystal layer 41 is sandwiched between glass plates 42 and a color filter 43 is disposed on the upper surface thereof, specifically, TN, STN, Display systems such as VA, IPS, and OCB can be used.

  The color filter 43 is not particularly limited, and for example, generally known color filters for liquid crystal display devices can be used. Such a color filter is usually composed of transparent colored patterns of red, green and blue, and each transparent colored pattern is made of a resin composition in which a colorant is dissolved or dispersed, preferably pigment fine particles are dispersed. Composed. The color filter may be formed by adjusting an ink composition colored in a predetermined color and printing it for each colored pattern. However, a paint type photosensitive material containing a colorant of a predetermined color may be used. It is more preferable to carry out by a photolithography method using a conductive resin composition.

  Further, the liquid crystal panel unit 4 may have a structure in which the upper and lower surfaces of the liquid crystal panel unit 4 are sandwiched between two polarizing plates. In this case, a polarizing plate 3a having the same configuration as that of the polarizing plate 3 is provided on the side surface opposite to the color filter 43 of the liquid crystal panel unit 4, but these two polarizing plates 3, 3a usually have mutual absorption axes. It arrange | positions so that it may become 90 degrees (cross Nicol).

  The primary light source of the backlight 5 is not particularly limited, but is preferably a white light emitting diode (white LED). The white LED is an element that emits white by combining a phosphor with a phosphor type, that is, a light emitting diode that emits blue light or ultraviolet light using a compound semiconductor. Above all, white light-emitting diodes, which consist of light-emitting elements that combine blue light-emitting diodes using compound semiconductors with yttrium, aluminum, and garnet yellow phosphors, have a continuous and broad emission spectrum. Therefore, it is suitable as a primary light source of the backlight in the present invention. Further, since white LEDs with low power consumption can be widely used, it is possible to achieve an energy saving effect.

  The display image of the touch panel device 10 is displayed in color as light emitted from the primary light source of the backlight 5 passes through the color filter 43. However, when the light transmitted through the color filter 43 is controlled so as to display a single color, if a conventionally used oriented polyester film is used as the transparent substrate 11 of the functional film 1 for improving image quality, Nizimura is stronger. May occur. On the other hand, since the touch panel device 10 includes the transparent base material 11 described above, even when such a single color display is used, it is possible to suitably suppress the occurrence of nitrile.

  As a preferred embodiment of the present invention described above, the touch panel device 10 in which the functional film 1 for improving image quality is arranged in a touch panel type display device having a liquid crystal display (LCD) has been described. The present invention is not limited to the above applications, and can be used for various other applications. Plasma used in various television receivers, display units for measuring instruments and instruments, display units for office equipment and computers, display units for telephones, display units for game machines, lighting signs (lighting advertisements), etc. It can be preferably used for a front-installed electromagnetic wave shielding filter of an image display device such as a display (PDP), a cathode ray tube display (CRT), a liquid crystal display (LCD), an electroluminescent display (EL) or the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example. In this specification, “part” and “%” are based on mass unless otherwise specified.

Example 1
<Create functional film for improving image quality>
[Conductive layer forming step]
First, a continuous strip-shaped electrolytic copper foil having a thickness of 10 μm was prepared as a metal foil for the conductive layer. Blackening layers made of copper-cobalt alloy fine particles were formed on both sides of the copper foil.
Moreover, the polyester resin-type primer layer was formed in one side of the multilayer transparent base material obtained at the said process.
Next, one surface of the multilayer transparent substrate and the glossy surface of the metal foil are bonded to a transparent two-component curable urethane resin adhesive (12 parts by mass of a polyester polyurethane polyol having an average molecular weight of 30,000 as a main component). (Including 1 part by mass of a xylylene diisocyanate-based prepolymer as a curing agent), followed by curing at 50 ° C. for 3 days, and a continuous adhesive layer having a thickness of 7 μm between the metal foil and the multilayer transparent substrate. A strip-shaped copper foil laminated sheet was obtained.
Next, a chemical etching treatment using a photolithography method was performed on the copper foil of the copper foil laminated sheet to form a touch panel sensor pattern including an opening portion and a line portion.
Specifically, the etching was consistently performed from masking to etching on the continuous belt-like laminated sheet using a production line for a color TV shadow mask. That is, after applying a photosensitive etching resist to the entire copper foil surface of the laminated sheet, a desired wiring pattern is closely exposed, developed, hardened, and baked, and a resist is formed on a region corresponding to the pattern opening. After forming the resist pattern in which the layer is not formed, the copper foil of the resist layer non-formed part is removed by etching with an acid aqueous etchant containing ferric chloride to have a copper pattern having an opening Then, water washing, resist peeling, washing, and drying were sequentially performed.
The pattern shape of the active area (image display region) was a shape in which a lattice pattern was arranged in a band shape, the line width was 10 microns, and the opening pitch was 300 microns. Further, an electrode pattern was formed around the periphery.
Furthermore, a sensor pattern for a touch panel including an opening and a line portion is formed on the other surface of the multilayer transparent substrate by performing the same process for preparing the electrolytic copper foil performed in the conductive layer forming step. did. However, the surface that has already been formed is masked by appropriately using the above-mentioned dry lamination technique to prevent corrosion in the etching process. Also, during pattern formation, alignment is adjusted so that the line directions of the respective line portions formed on both surfaces of the multilayer transparent substrate are orthogonal to each other in plan view. Part was formed.

[Microprojection layer forming process]
The transparent substrate resin obtained in the conductive layer forming step was processed as follows to form a microprojection layer on the surface where the conductive layer was not formed.
An acrylate-based ultraviolet curable resin generally used by a die was applied to a transparent substrate that was continuously transported under tension by the roll-to-roll method. Subsequently, the surface on which the ultraviolet curable resin of the transparent substrate resin is applied is pressed and pressed on the peripheral side surface of the roll plate, which is a mold for molding, whereby the ultraviolet curable resin is applied to the transparent substrate resin. At the same time, it was filled with an ultraviolet curable resin in a concave portion having a minute uneven shape. Subsequently, the ultraviolet curable resin is cured by irradiation with ultraviolet rays (1000 mJ / cm 2) to form minute protrusions on the surface of the transparent substrate resin. Subsequently, the transparent substrate resin was peeled off from the roll plate integrally with the cured ultraviolet curable resin via a peeling roller.
After peeling, the transparent substrate resin was cut into a size of 480 mm × 280 mm to obtain functional films for improving image quality in Examples and Comparative Examples.
Moreover, about the roll plate, it produced by performing the anodizing process and the etching process on the following conditions with the method mentioned above.
Anodizing treatment: An oxalic acid solution (water temperature 10 ° C., concentration 5%) was applied, and anodizing treatment was performed at an applied voltage of 10 to 70V.
Etching treatment: A phosphoric acid solution (water temperature 30 ° C., concentration 20%) was applied.
The above process was repeated a total of 6 times.

<Create sensor for touch panel>
The above-mentioned functional film for improving image quality, on which a conductive layer and a fine protrusion layer are formed, is laminated on a glass plate having a thickness of 3 mm via a transparent adhesive layer having a thickness of 25 μm. A touch panel sensor was prepared by stacking a punched base material for protection.
<Create touch panel device>
Next, the obtained touch panel sensor was placed above the polarizing plate on the observer side of the liquid crystal monitor (FLATRON IPS226V (manufactured by LG Electronics Japan)) so that the glass plate came to the observer side, and a touch panel device was created. . The touch panel sensor was arranged so that the angle formed by the slow axis of the transparent substrate of the touch panel sensor and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Example 2)
The same method as in Example 1 except that the angle formed by the slow axis of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 30 °. A touch panel device was produced.

(Example 3)
The same method as in Example 1 except that the angle formed by the slow axis of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 60 °. A touch panel device was produced.

Example 4
The same method as in Example 1 except that the angle formed by the slow axis of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 90 °. A touch panel device was produced.

(Example 5)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 8200 nm, film thickness = 92 μm, and Δn = 0.089. A touch panel device was produced in the same manner as in Example 1 except that the obtained transparent substrate was used.

(Example 6)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 19000 nm, film thickness = 190 μm, and Δn = 0.10. A touch panel device was produced in the same manner as in Example 1 except that the obtained transparent substrate was used.

(Example 7)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 7500 nm, film thickness = 75 μm, and Δn = 0.10. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Example 8)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 7500 nm, film thickness = 94 μm, and Δn = 0.08. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

Example 9
The draw ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a polarizing plate transparent substrate having retardation = 6100 nm, film thickness = 61 μm, and Δn = 0.10. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Example 10)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 6100 nm, film thickness = 81 μm, and Δn = 0.075. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Example 11)
Example 9 except that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 45 °. A touch panel device was produced in the same manner as described above.

(Example 12)
The same method as in Example 1 except that the angle formed between the slow axis of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was set to 45 °. A touch panel device was produced.

(Comparative example)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having a retardation of 2750 nm, a film thickness of 45 μm, and Δn = 0.061. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Reference Example 1)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 6100 nm, film thickness = 160 μm, and Δn = 0.038. They were arranged so that the angle formed by the slow axis (average orientation angle) of the transparent substrate constituting the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °. The orientation angle difference of this transparent substrate was 6.6 degrees.

(Reference Example 2)
The stretch ratio of the unstretched film obtained in the same manner as in Example 1 was adjusted to obtain a transparent substrate having retardation = 7500 nm, film thickness = 188 μm, and Δn = 0.040. A touch panel device was produced in the same manner as in Example 1 except that the obtained transparent substrate was used.

(Measurement of average orientation angle and orientation angle difference)
For the touch panel devices according to Examples 7 to 11 and Reference Examples 1 and 2, the average orientation angle and the orientation angle difference in the slow axis direction of the transparent substrate were measured. For the measurement, a molecular orientation analyzer (MOA) manufactured by Oji Scientific Instruments was used, and as shown in FIG. 2, on a liquid crystal monitor (21.5 inches, monitor vertical direction 27 cm, horizontal direction 48 cm) A total of 40 orientation angles were measured at 5 cm intervals in both the direction and the left-right direction, the average value was the average orientation angle, and the orientation angle difference was a value obtained by subtracting the minimum value from the maximum value of the measured orientation angles. The measurement results of the orientation angle difference are as described in Table 1. In addition, about the orientation angle difference of the transparent base material of a comparative example, naturally it is estimated that it is a value close | similar to the orientation angle difference of the multilayer transparent base material of Examples 7-11 from the draw ratio, film thickness, etc. .

<Nizimura evaluation>
In the dark place and the bright place (liquid crystal monitor peripheral illuminance 400 lux), the five people in the front and oblique directions (about The display image was observed visually and in a bright place through polarized sunglasses, and the presence or absence of nidimra was evaluated according to the following criteria.
A: Nizimura is not observed.
B: Nizimura is observed, but it is thin and has no problem in practical use.
C: Nizimura is observed.
D: Nizimura is strongly observed.

  As shown in Table 1, the retardation of the transparent substrate of the functional film for improving image quality is 6000 nm or more, and the slow axis of the transparent substrate of the functional film for improving image quality and the absorption axis of the polarizing plate are The touch panel device according to the example in the range of 0 ° ± 30 ° or 90 ° ± 30 ° was excellent in the visual evaluation of the bright spot in the bright place and the dark place. On the other hand, the touch panel device according to Examples 11 to 12 in which the angle formed between the slow axis of the transparent substrate of the functional film for improving image quality and the absorption axis of the polarizing plate was 45 ° Although it was inferior to the evaluation of Nizimura over polarized sunglasses, the evaluation of Nizimura in the dark is good, and Nizimura can be suppressed within a practically preferable range.

(Modification 1)
The angle formed by the slow axis of the transparent substrate of the functional film for improving image quality and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor is an arbitrary angle, and the other methods are the same as in Example 1. About the created touch panel apparatus, it is a thing which can suppress a nidimra to the practically preferable range in the use in a dark place.

  As described above, from the examples, the functional film for improving image quality according to the present invention and the touch panel device using the functional film can be applied to touch panel devices that can extremely highly suppress the occurrence of nitrile on the screen and require high quality. I understand what I can do.

<Evaluation of newton ring prevention effect>
As Comparative Example 2, a touch panel device having the same material, configuration, and manufacturing method as in Example 1 was prepared except that no fine protrusion layer was formed on any surface of the transparent base material of the functional film for improving image quality. When the same level of finger pressure was applied to the touch panel screen, Newton's ring was visually confirmed in Comparative Example 2, but no Newton's ring was observed in Example 1.

(Modification 2)
A functional film for improving image quality, in which no conductive layer was provided on the transparent substrate and only a fine protrusion layer was provided, was prepared as a film of Modification 2. The film of Modification 1 was placed between the touch panel sensor and the polarizing plate in the touch panel device of Comparative Example 2 to obtain the touch panel device of Modification 2. When the effect of preventing the occurrence of Newton rings was verified in the same manner as described above, in the touch panel device of Modification Example 2, the occurrence of Newton rings was reduced to such an extent that visual confirmation was difficult.

  As described above, the functional film for improving image quality according to the present invention reduces reflected light that lowers visibility, and at the same time, can extremely prevent the occurrence of Nizimura and Newton rings, and is suitable for touch panel devices that require high quality. It can be understood that it can be used for the following.

DESCRIPTION OF SYMBOLS 1, 1A Image quality improvement functional film 11 Transparent base material 110 Base material 12 Micro projection layer 120 UV curable resin 13 Conductive layer 2 Touch panel unit 3 Polarizing plate 4 Liquid crystal panel unit 41 Liquid crystal layer 42 Glass plate 43 Color filter 5 Backlight 100 Manufacturing Process 101 Die 102 Roll Plate 103, 104 Roller

Claims (11)

In the functional film for improving image quality, the minute protrusions are closely arranged on the resin substrate, and the interval between the adjacent minute protrusions is equal to or less than the shortest wavelength of the wavelength band for preventing reflection.
The functional film for improving image quality, wherein the resin substrate is a transparent substrate having a retardation of 6000 nm or more.   The functional film for improving image quality according to claim 1, wherein conductive layers arranged in the same direction at a constant pitch are formed on at least one surface of the transparent substrate.   The transparent substrate has a refractive index (nx) in the slow axis direction that is the direction with the highest refractive index in the plane and a refractive index (ny) in the fast axis direction that is orthogonal to the slow axis direction. The functional film for improving image quality according to claim 1, wherein the difference (nx−ny) is 0.05 or more.   The transparent base material is a polyester resin, a polyolefin resin, a (meth) acrylic resin, a polyurethane resin, a polyether sulfone resin, a polycarbonate resin, a polysulfone resin, a polyether resin, or a polyether ketone resin. The functional film for improving image quality according to any one of claims 1 to 3, comprising any one material selected from the group consisting of: a (meth) acrylonitrile resin and a cycloolefin resin.   The functional film for improving image quality according to claim 4, wherein the transparent substrate is polyethylene terephthalate. A functional film for improving image quality according to any one of claims 1 to 5,
A touch panel unit;
An image display panel. A polarizing plate disposed on the light exit surface side of the image display panel;
The display device according to claim 6, wherein the image display panel is a liquid crystal panel.   The angle formed by the absorption axis of the polarizing plate and the slow axis of the transparent substrate of the functional film for improving image quality is arranged to be 0 ° ± 30 ° or 90 ° ± 30 °. The display device according to claim 7.   The display device according to claim 7 or 8, wherein the functional film for improving image quality is laminated on a surface of the polarizing plate on the touch panel unit side.   The display device according to claim 6, wherein the functional film for improving image quality is laminated on a back surface side of the touch panel unit. The display device according to claim 6, wherein the functional film for improving image quality is laminated on a surface side of the touch panel unit.
The display device according to claim 7, wherein the functional film for improving image quality is laminated on a surface of the polarizing plate on the touch panel unit side.

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