JP2014010315A - Sensor film for touch panel and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor film for a touch panel, the sensor film being able to extremely accurately restrict irregular occurrence of different colors on a liquid crystal display image.SOLUTION: A sensor film 3 for a touch panel is formed such that conductive pattern layers 311 and 312 are laid over a multi-layer transparent substrate 30 formed by arranging a plurality of transparent base materials 301 and 302 in layers, laid or between the layers of the multi-layer transparent substrate 30. In the sensor film 3, the transparent base materials 301 and 302 composing the multi-layer transparent substrate 30 have a retardation of 3000 nm or greater.

Description

  The present invention relates to a sensor film for a touch panel and a display device using the same.

  In recent years, a display device equipped with a touch panel has been rapidly spread, and in particular, a demand for a device capable of multi-touch such as a capacitance method is increasing. There is also a high demand for lighter and smaller touch panels and larger touch panels. As a transparent electrode used for a touch panel, a transparent conductive material such as ITO is generally used. However, in recent years, a type in which a metal is patterned has been studied. As a base material, a type using glass or a transparent film is used. Things are used.

  By the way, when a film is used as a transparent substrate for a touch panel sensor for a liquid crystal display device, unevenness of different colors (hereinafter also referred to as “Nizimura”) occurs in the liquid crystal display device, particularly when the display screen is observed obliquely. It has been found that there is a problem that the display quality of the liquid crystal display device is impaired. This phenomenon is caused by the birefringence of the film base material, and it is necessary to improve it in order to meet the strict demand for display quality in recent years. For this reason, a film made of cellulose ester represented by general triacetyl cellulose as a base material having no birefringence has been used as the transparent base material used for this type of film. However, cellulose esters are generally expensive, and the problem of dimensional change and curling due to moisture absorption remains.

  From the problem of such a cellulose ester film, it is desired to use a versatile film that is easily available in the market or that can be produced by a simple method as a transparent substrate. Attempts have been made to use polyester films such as polyethylene terephthalate (PET) as an alternative film (see Patent Document 1).

  However, according to the researches of the present inventors, when a polyester film such as PET is used as a cellulose ester film substitute film, Nijimura appears in the liquid crystal display device, particularly when the display screen is observed obliquely. It has been found that there is a problem that display quality is impaired.

JP 2010-204630 A

  The present invention has been made in view of such a situation, and in view of the above-described situation, a sensor film for a touch panel capable of extremely highly suppressing the occurrence of nitrile in a touch panel type liquid crystal display device is provided. With the goal.

  The present inventor conducted extensive research to solve the above-mentioned problems, and further examined the problem of the sensor film for touch panel using such a polyester film. By using a multilayer transparent substrate formed by laminating a plurality of polyester films having a value, it was found that the problem of Nizimura can be improved compared to the case of using a transparent substrate made of a conventional polyester film, and the present invention It came to be completed. More specifically, the present invention provides the following.

  (1) A sensor film for a touch panel in which a conductive pattern layer is laminated on a multilayer transparent substrate obtained by laminating a plurality of transparent substrates, or between layers of the multilayer transparent substrate, the multilayer transparent substrate The said transparent base material which comprises is what has a retardation of 3000 nm or more, The sensor film for touchscreens characterized by the above-mentioned.

  (2) The transparent base material has a refractive index (nx) in the slow axis direction that is the direction having the largest refractive index in the plane, and a refractive index in the fast axis direction that is a direction orthogonal to the slow axis direction. The difference (nx−ny) with respect to (ny) is 0.05 or more, and the sensor film for a touch panel as described in (1).

  (3) The transparent substrate is made of polyester resin, polyolefin resin, (meth) acrylic resin, polyurethane resin, polyether sulfone resin, polycarbonate resin, polysulfone resin, polyether resin, polyether. The sensor film for a touch panel according to (1) or (2), which is made of any one material selected from the group consisting of a ketone-based resin, a (meth) acrylonitrile-based resin, and a cycloolefin-based resin.

  (4) The display apparatus provided with the sensor film for touchscreens in any one of (1) to (3), and a polarizing plate.

  (5) A display device comprising the touch-panel sensor film according to any one of (1) to (3), a polarizing plate, and a liquid crystal panel.

  (6) In the display device according to (5), an angle formed between the absorption axis of the polarizing plate and the slow axis direction of the multilayer transparent base material of the sensor film for the touch panel is 0 ° ± 30 ° or 90 °. A display device, wherein the display device is arranged to be ± 30 °.

  (7) The display device according to (5) or (6), wherein the liquid crystal panel is provided with a backlight whose primary light source is a white light emitting diode.

  (8) A display device including a touch panel sensor film in which a conductive pattern layer is laminated on a transparent substrate, and a polarizing plate, the display device including the transparent substrate. The display device is further provided with a functional layer, and the touch panel sensor film and the transparent substrate constituting the functional layer both have a retardation of 3000 nm or more.

  (9) The display device according to (8), wherein the functional layer is a protective film disposed on an outermost surface on a display surface side of the display device.

  (10) The display device according to (8), wherein the functional layer is a scattering prevention film disposed on an outermost surface on a display surface side of the display device.

  Since this invention consists of an above-mentioned structure, it can provide the sensor film for touch panels which can suppress very much that a display image arises in a display image, and a display apparatus provided with the same.

It is sectional drawing which shows typically the touchscreen apparatus which is an example of the display apparatus of this invention.

  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”.

  As shown in FIG. 1, a touch panel device 1, which is an example of a display device using a touch panel sensor film 3 of the present invention, includes a transparent surface substrate 2, a touch panel sensor film 3, a polarizing plate 4, a color filter 5, and a liquid crystal panel. 6 has a configuration arranged in this order. The touch panel device 1 has a backlight 8 on the side opposite to the color filter 5 of the liquid crystal panel 6 and may have a structure in which the liquid crystal panel 6 is sandwiched between two polarizing plates. A polarizing plate 7 having the same configuration as that of the polarizing plate 4 is provided on the side surface opposite to the color filter 5 of the liquid crystal panel 6. The two polarizing plates 4 and 7 usually have an absorption axis of 90 °. Is arranged (crossed Nicols).

<Sensor film for touch panel>
As shown in FIG. 1, the touch panel sensor film 3 includes a multilayer transparent base material 30 formed by laminating a transparent base material 301 and a transparent base material 302 from the surface side facing the transparent surface substrate 2 in the touch panel device 1. A base material 33 is laminated via a transparent adhesive layer 34. As will be described in detail later, conductive pattern layers 311 (X direction) and 312 (Y direction) are formed on the back surfaces of the transparent base material 301 and the transparent base material 302, respectively.

  The multilayer transparent substrate 30 is a multilayer resin substrate formed by laminating transparent substrates 301 and 302. The number of transparent substrates to be laminated may be two or more, and the number of layers is not particularly limited, but in general from the viewpoint of necessary performance, preferable thickness, desirable cost, etc., transparent substrates are generally used. A multilayer transparent substrate obtained by laminating 2 to 3 layers can be preferably used. Each of the transparent base materials 301 and 302 can be formed as a multilayer transparent base material 30 by being laminated via the transparent adhesive layer 34.

  In addition, the multilayer transparent base material 30 is a range other than the transparent base materials 301 and 302 as long as necessary light transmittance can be maintained so that the conductive pattern layers 311 (X direction) and 312 can be exemplified. Other layers and members may be further laminated thereon or disposed between the layers.

  The transparent substrates 301 and 302 constituting the multilayer transparent substrate 30 have a retardation of 3000 nm or more. If the retardation of the transparent base materials 301 and 302 is less than 3000 nm, for example, even when the multilayer transparent base material 30 in which these two layers are stacked is used, a display image of the touch panel device 1 is distorted. On the other hand, the upper limit of the retardation of the transparent substrates 301 and 302 is not particularly limited, but is preferably 30000 nm or less, 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.

  In addition, in order to produce the effect of the present invention that suppresses the occurrence of nitrite in the touch panel device, for example, a transparent substrate disposed using a material such as the cellulose ester described above or a film by a special manufacturing method. There were means such as limiting the retardation range, but as mentioned above, the product itself is expensive, and there are various restrictions on the material strength, so that it can be used for general use in a usage environment such as a touch panel. Was not appropriate (here, the range of retardation of the transparent substrate unsuitable for use is 400 nm ≦ Re <3000 nm as a result of our study). As another method for suppressing the occurrence of nitrite, a single-layer transparent substrate having a high retardation of 6000 nm or more may be disposed, but a substrate having such a high retardation value is generally used. This is not preferable, and is not preferable in terms of increasing procurement or manufacturing costs. The sensor film 3 for a touch panel of the present invention can be manufactured by a combination of general-purpose transparent base materials having an arbitrary range of 3000 nm or more, which is a general range of retardation values, and the base material itself is determined from the manufacturing conditions. The thickness can be reduced. As a result, in the touch panel device, it is possible to increase the touch detection sensitivity, thereby contributing to the component reliability by improving the adhesion between members, the design by improving the body design freedom, and the weight reduction. Further, these functions have a sufficient effect by stacking at least two sheets. As mentioned above, the sensor film 3 for touch panels of this invention using the multilayer transparent base material 30 which can be manufactured with the combination of general purpose transparent base materials 301, 302 etc. is preferable in both performance improvement and cost reduction.

  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 substrates 301 and 302 is not particularly limited as long as the above-described retardation is satisfied. For example, a polyester resin, a polyolefin resin, a (meth) acrylic resin, a polyurethane resin, a polyresin Preferred is one selected from the group consisting of ether sulfone resins, polycarbonate resins, polysulfone resins, polyether resins, polyether ketone resins, (meth) acrylonitrile resins, and cycloolefin resins. Used for. Especially, it is preferable that the said transparent base material consists of polyethylene terephthalate (PET). This is because polyethylene terephthalate is highly versatile and easily available. In the present invention, a sensor film for a touch panel capable of producing a touch panel device having a high display quality can be obtained even with a highly versatile film such as PET. Furthermore, PET is excellent in transparency, heat or mechanical properties, can control the retardation by stretching, has a large intrinsic birefringence, and can obtain a large retardation relatively easily even when the film thickness is small.

  The method for obtaining the transparent base materials 301 and 302 is not particularly limited as long as the above-described retardation is satisfied. For example, when the material is made of polyester such as PET, the material polyester is melted and extruded into a sheet. A method may be mentioned in which the unstretched polyester is subjected to 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. If the transverse draw ratio exceeds 6.0 times, the transparency of the resulting transparent substrate made of polyester tends to be lowered, and if the draw ratio is less than 2.5 times, the draw tension becomes small. In some cases, the birefringence of the transparent base material to be obtained becomes small, and the retardation cannot be increased to 3000 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). Also good. 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 produced by the above-described method to 3000 nm or more include a method of appropriately setting the draw ratio, the draw temperature, and the film thickness of the produced transparent substrate. 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 base materials 301 and 302 is appropriately determined according to the constituent materials and the like, but is preferably in the range of 20 μm to 500 μm. When the thickness is less than 20 μm, the retardation of the transparent base materials 301 and 302 may not be 3000 nm or more, and the anisotropy of the mechanical properties becomes remarkable, and tearing, tearing, and the like are likely to occur. May be significantly reduced. 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. The more preferable lower limit of the thickness of the transparent substrate is 30 μm, the more preferable upper limit is 400 μm, and the still more preferable upper limit is 300 μm.

  The transparent base materials 301 and 302 preferably have 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).

  The transparent base materials 301 and 302 are made into the multilayer transparent base material 30 by laminating | stacking the slow axis along either the X direction or the Y direction of a base material in the same direction. In the present specification, the direction of the slow axis of each of the transparent base materials 301 and 302 that are overlapped with each other is defined as the slow axis of the multilayer transparent base material 30 constituted by the transparent base materials 301 and 302. The direction.

  In the actual production of the multilayer transparent substrate, the combination of the directions of the slow axes is not limited to the above, and other combinations can provide the same effects as those of the present invention. For example, even if the slow axis direction is not exactly superimposed in the same direction, if the substantial retardation as a multilayer transparent substrate is in the same range as the present invention, such Multilayer transparent substrates are also within the equivalent scope of the present invention. Here, as a preferable feasible example in which the direction of the slow axis can be easily determined from the stretching direction of the resin material, the direction of the slow axis is determined as described above.

  The transparent base materials 301 and 302 preferably have an orientation angle difference in the slow axis direction of 6 ° or less, more preferably 4 ° or less, and still more preferably 2 ° or less. As the polarization angle difference between the transparent substrates 301 and 302 is within 6 °, as will be described later, in the touch panel device 1, the absorption axis of the polarizing plate 4 and the slow axis direction of the multilayer transparent substrate 30 are formed. It is possible to particularly prevent the occurrence of nitrite when the angle is set to 0 ° or 90 °. This is because if the transparent base materials 301 and 302 have a large orientation angle difference exceeding 6 °, the light transmittance is increased and interference colors are generated.

  The conductive pattern layers 311 and 312 may be formed by patterning a transparent conductive material layer formed on the multilayer transparent substrate 30 or the transparent substrates 301 and 302, and patterning an opaque metal layer. Depending on the presence, it may appear transparent.

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

  As the metal layer, any metal having conductivity 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 pattern layers 311 and 312, photolithography (etching), transfer, self-assembly, and the like can be applied after pattern printing and formation of the conductive foil on the surface. From the viewpoint of improving cost performance, it is particularly preferable to form 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 pattern-forming a conductive pattern layer with a conductive composition containing metal particles and a binder resin by pattern printing, the metal particles can be used as long as they have conductivity, as exemplified above. The conductive pattern layers 311 and 312 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 sensor film 3 for a touch panel, a primer layer (between the transparent base materials 301 and 302 and the conductive pattern layers 311 and 312 is provided in order to improve the adhesion between the transparent base materials 301 and 302 and the conductive pattern layers 311 and 312. (Not shown) is preferably provided. The primer layer has good adhesion to both the transparent base materials 301 and 302 and the conductive pattern layers 311 and 312, and is a transparent layer for ensuring light transmission of the opening (conductive pattern layer non-formed portion). is there. Furthermore, when the conductive pattern layers 311 and 312 are formed by a specific intaglio printing method as will be described later, the primer layer is provided on the transparent base materials 301 and 302 in a state where fluidity can be maintained. It is a layer formed as a layer to be solidified from a liquid while in contact with the intaglio, and is a layer solidified when the final conductive pattern layers 311 and 312 are formed.

  The conductive pattern layers 311 and 312 may be appropriately formed or treated with other layers 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.

  The conductive pattern layers 311 and 312 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, on the multilayer transparent substrate 30 or the transparent substrates 301 and 302, a copper foil is dry-laminated via a primer layer to form a continuous strip-shaped copper foil laminated sheet, Conductive pattern layers 311 and 312 can be formed by performing a chemical etching process using a photolithography method on the copper foil of the copper foil laminated sheet. In particular, when a line width of less than 10 μm is required, it can be achieved by preferably processing using a metal foil having a thickness corresponding to the line width. A thin metal layer having a thickness of 2 μm or less is formed on the multilayer transparent substrate 30. Or what formed by vapor deposition, sputtering, etc. on the transparent base materials 301 and 302 may be similarly patterned by photolithography.

<Touch panel device>
The touch panel device 1 using the touch panel sensor film 3 described above is also one aspect of the present invention. Hereinafter, a touch panel device 1 will be described as a preferred embodiment of the display device of the present invention.

  In the touch panel device 1, the polarizing plates 4 and 7 are not particularly limited as long as they have desired polarization characteristics, and those generally used for polarizing plates of liquid crystal display devices can be used. Specifically, for example, a polyvinyl alcohol film is stretched, and a polarizing plate containing iodine is preferably used.

  In addition, the structure which integrated the touch panel unit comprised including the sensor film 3 for touch panels, and a polarizing plate can be mentioned as another preferable example which concerns on a polarizing plate. According to such an integrated configuration, the multilayer transparent substrate 30 of the present invention can also serve as a polarizing plate protective film, thereby simplifying the overall layer configuration of the touch panel device, transparency, and interface reflectivity. Can be improved.

  The color filter 5 is not particularly limited, and for example, a generally known color filter for a liquid crystal display device 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.

  The liquid crystal panel 6 is not particularly limited, and generally known liquid crystal panels for liquid crystal display devices can be used. For example, as shown in FIG. 1, a liquid crystal panel having a general structure in which a liquid crystal layer 61 is sandwiched between glass plates 62, specifically, a display method such as TN, STN, VA, IPS and OCB. Can be used.

  The primary light source of the backlight 8 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 1 is displayed in color when light emitted from the primary light source of the backlight 8 passes through the color filter 5. However, when the light transmitted through the color filter 5 is controlled so as to be displayed in a single color, if a conventionally used oriented polyester film is used as the transparent substrate of the touch panel sensor film 3, Nizimura may be generated more strongly. is there. On the other hand, since the touch panel device 1 has the multilayer transparent base material 30 described above, even when such a monochromatic display is used, it is possible to suitably suppress the occurrence of nitrite.

  In the touch panel device 1, the touch panel sheet is formed so that the angle formed between the slow axis direction of the multilayer transparent substrate 30 and the absorption axis of the polarizing plate 4 is in a range of 0 ° ± 30 ° or 90 ° ± 30 °. 3 and the polarizing plate 4 are preferably disposed, more preferably in the range of 0 ° ± 10 ° or 90 ° ± 10 °, and in the range of 0 ° ± 7 ° or 90 ° ± 7 °. The touch panel sheet 3 and the polarizing plate 4 are preferably disposed so that the angle is 0 ° or 90 °, more preferably in the range of 0 ° ± 3 ° or 90 ° ± 3 °. Most preferred. Since the angle formed between the direction of the slow axis of the multilayer transparent substrate 30 and the absorption axis of the polarizing plate 4 is within the above range, it is extremely highly possible that the display image of the touch panel device 1 is not distorted. Can do. 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, this environment is also referred to as “dark place”), the retardation of the transparent base materials 301 and 302 is set to 3000 nm or more, thereby enabling the touch panel device 1. The occurrence of azimuth irregularities can be suppressed at any angle between the slow axis direction of the multilayer transparent substrate 30 and the absorption axis of the polarizing plate. 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 between the slow axis direction of the multilayer transparent substrate 30 and the absorption axis of the polarizing plate 4 is not within the above range, azimuth is generated and display quality is deteriorated. Further, since the light of the backlight 8 transmitted through the color filter 5 is not limited to one having a continuous wide spectrum, the angle formed between the slow axis direction of the multilayer transparent substrate 30 and the absorption axis of the polarizing plate 4. If it is not within the above-mentioned range, it is estimated that the image quality is deteriorated and the display quality is deteriorated. In addition, when using and laminating | stacking several sensor films 3 for touch panels, and also laminating | stacking a transparent base material on the outermost surface as a protective film, it is preferable to enter into the said angle range about all the layers.

  Here, the transmittance of light transmitted through the two polarizing plates placed in the crossed Nicols state is expressed by the following formula (Equation 2). In the following formula 2, I / I0 represents the transmittance of light transmitted through the 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) formed by the slow axis direction of the multilayer transparent substrate 30 with respect to the absorption axis of the polarizing plate 4 is 45 °, the light transmittance becomes maximum, but the transmittance Changes depending on the retardation of the multi-layer transparent substrate 30 and the wavelength of transmitted light, and therefore, interference colors peculiar to the retardation value (Nizimura etc.) are observed. Here, when the angle (θ) is set to 0 ° or 90 °, the light transmittance is zero, so that no interference color is observed.

    (Expression 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).

  Further, the touch panel device 1 may have a structure in which an arbitrary layer is formed on the touch panel sensor film 3 as a single layer and / or a plurality of 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 electromagnetic wave shielding layer. And an adhesive layer.

  In addition to the touch panel device 1 using the touch panel sensor film 3 described above, a conductive pattern is formed on a single-layer transparent base material having a retardation of 3000 nm or more like the transparent base materials 301 and 302 instead of the touch panel sensor film 3. A touch panel device using a sensor film for a touch panel in which layers are laminated and further including another functional layer including a single-layer transparent substrate having a retardation of 3000 nm or more is also within the scope of the present invention. . This invention is not only in the case where a single layer transparent substrate having a retardation of 3000 nm or more is integrated in a sensor film for a touch panel in a form that constitutes a multilayer transparent substrate, but has a retardation of 3000 nm or more. Even if the single-layer transparent substrate has a separate touch panel sensor film as part of the other functional layers in the touch panel device, the effect of the present invention can be achieved. Some are based on knowledge.

  In the touch panel device having the above configuration, the single-layer transparent substrate having a retardation of 3000 nm or more preferably has an orientation angle difference in the slow axis direction of 6 ° or less, more preferably 4 ° or less. More preferably, it is within 2 °. When the difference in polarization angle of the transparent base material is within 6 °, the occurrence of ND when the angle between the absorption axis of the polarizing plate and the direction of the slow axis of the transparent base material is set to 0 ° or 90 ° Can be prevented in particular.

  As a preferable example of the touch panel device having the above-described configuration, a touch panel device in which the other functional layer is a protective film disposed on the surface of the touch panel sensor film or the transparent surface substrate can be exemplified. This protective film comprises a transparent substrate having a retardation of 3000 nm or more, and the sensor film for the touch panel is formed by laminating a conductive pattern layer on a single-layer transparent substrate having a retardation of 3000 nm or more. Even in the case of a sensor film for a touch panel, a touch panel device having these structural requirements can suppress the occurrence of nitrile as with the touch panel device 1.

  Moreover, as another preferred example, a touch panel device in which the other functional layer is a scattering prevention film disposed on the surface of the touch panel sensor film can be exemplified. This scattering prevention film comprises a transparent substrate having a retardation of 3000 nm or more, and the sensor film for the touch panel has a conductive pattern layer laminated on a single-layer transparent substrate having a retardation of 3000 nm or more. Even in the case of a sensor film for a touch panel, the touch panel device provided with these constituent requirements can suppress the occurrence of nitrile as with the touch panel device 1. The anti-scattering film is mainly disposed in close contact with the outermost surface of the touch panel device, and is particularly suitable for the PET material described above. Its function is a lower glass due to the adhesion of the film and its own ductility when the screen is damaged. Suppresses deterioration of screen visibility and operability due to injuries of users and surrounding people due to splashes, etc., loss of water resistance and sealing resistance, damage to the screen, and falling off of fragments. In the meantime, it can be used for the time being.

  By providing flexibility to the arrangement of the transparent base material in the touch panel device as in the above configuration, the composite function of each layer (for example, a protective film) is maintained while maintaining the same effect as the touch panel device 1 in preventing the occurrence of nitriles. And a touch panel, a touch panel and a polarizing plate protective film, and other anti-reflection, etc.), and the thickness of the sensor film for the touch panel can be further reduced.

  As a preferred embodiment of the present invention, the touch panel device 10 in which the touch panel sensor film 3 is arranged in a touch panel type display device including a liquid crystal display (LCD) has been described. The sensor film 3 for a touch panel of the present invention can be particularly preferably used for a transparent antenna or the like provided in a transparent electrode of a touch panel device or a mobile phone. By providing the touch panel sensor film 3, in the touch panel device 1, it is possible to prevent touch misidentification and malfunction due to touch recognition lock due to abnormality detection, and image noise and image disturbance due to malfunction of the LCD drive circuit. Can be prevented.

  Moreover, the sensor film 3 for touch panels is not restricted to the said use, It can be used also for other various uses. 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. In addition, it can also be used for electromagnetic wave shielding filter applications such as building windows, vehicles, ships, aircraft, or microwave oven windows.

  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 sensor film for touch panel>
The sensor film for touch panels used for the touch panel device of Example 1 was created by the following steps.
[Create transparent substrate]
The polyethylene terephthalate material was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely adhered onto a water-cooled and cooled rotating quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute with a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), and then stretched at 120 ° C. at a stretch ratio of 4.5 times. The film was stretched in the direction of the degree at a stretching ratio of 1.5 times to obtain a transparent substrate having retardation = 3300 nm, film thickness = 33 μm, and Δn = 0.099.
Three sheets (three layers) of the obtained transparent substrates were laminated through a transparent adhesive layer to obtain a multilayer transparent substrate. As the transparent adhesive, an acrylic transparent adhesive containing a conventionally known antioxidant was used.
[Conductive pattern layer forming step]
First, as a metal foil for the conductive pattern layer, a continuous strip-shaped electrolytic copper foil having a thickness of 10 μm was prepared. 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, the touch panel sensor pattern including the opening and the line portion is similarly 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 pattern layer forming step. Formed. 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 adjustment is performed so that the direction of each line portion formed on both surfaces of the multilayer transparent substrate is perpendicular to each other in plan view. Part was formed.
<Create sensor for touch panel>
The above touch panel sensor film is laminated on a glass plate having a thickness of 3 mm through a transparent adhesive layer having a thickness of 25 microns, and the transparent base material of Example 1 is punched to a predetermined size to protect the sensor film. For this reason, a touch panel sensor was laminated.
<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 produced. . 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 touch panel device is manufactured in the same manner as in Example 1 except that the angle formed between the slow axis direction of the multilayer transparent substrate of the touch panel sensor and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor is 30 °. Was made.

(Example 3)
The touch panel device is manufactured in the same manner as in Example 1 except that the angle formed by the slow axis direction of the multilayer transparent substrate of the touch panel sensor and the absorption axis of the polarizing plate on the viewer side of the liquid crystal monitor is 60 °. Was made.

Example 4
The touch panel device is manufactured in the same manner as in Example 1 except that the angle formed by the slow axis direction of the multilayer transparent substrate of the touch panel sensor and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor is 90 °. Was made.

(Example 5)
The touch panel device is manufactured in the same manner as in Example 1 except that the angle formed between the slow axis direction of the multilayer transparent substrate of the touch panel sensor and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor is 45 °. Was made.

(Example 6)
A touch panel device was produced in the same manner as in Example 1 except that the number of laminated transparent substrates obtained in the same manner as in Example 1 was 2 (2 layers).

(Example 7)
A touch panel device was produced in the same manner as in Example 1 except that the number of transparent substrates obtained in the same manner as in Example 1 was 6 (6 layers).
(Example 8)
A sensor film for a touch panel is prepared using the single-layer transparent substrate obtained in Example 1 instead of the multilayer transparent substrate in Example 1, and further examples are provided on the glass plate of the touch panel sensor. A touch panel device was produced in the same manner as in Example 1 except that the single-layer transparent substrate obtained in 1 was laminated as a protective film.

(Comparative Example 1)
Instead of the multilayer transparent substrate in Example 1, the following single-layer transparent substrate was used. About the others, the touchscreen apparatus was produced by the method similar to Example 1. FIG. The single-layer transparent substrate used in Comparative Example 1 was obtained by adjusting the stretching ratio in the production of the transparent substrate in Example 1, and had a retardation = 2800 nm, a film thickness = 100 μm, and Δn = 0.028. It is a substrate.

(Comparative Example 2)
Instead of the multilayer transparent substrate in Example 1, the following single-layer transparent substrate was used. About the others, the touchscreen apparatus was produced by the method similar to Example 1. FIG. The single-layer transparent substrate used in Comparative Example 2 was obtained by adjusting the stretching ratio in the production of the transparent substrate in Example 1, and had a retardation = 930 nm, a film thickness = 33 μm, and Δn = 0.028. It is a substrate.

(Comparative Example 3)
The draw ratio in the production of the transparent substrate in Example 1 was adjusted to obtain a transparent substrate having retardation = 2000 nm, film thickness = 33 μm, and Δn = 0.061. A touch panel device was produced in the same manner as in Example 6 except that this transparent substrate was used.

(Reference example)
Instead of the multilayer transparent substrate in Example 1, the following single-layer transparent substrate was used. About the others, the touchscreen apparatus was produced by the method similar to Example 1. FIG. The single-layer transparent substrate used in this reference example was obtained by adjusting the stretching ratio in the production of the transparent substrate in Example 1, and was obtained by adjusting the retardation = 9900 nm, the film thickness = 100 μm, and Δn = 0.099. It is a material.

<Nizimura evaluation>
The touch panel devices produced in Examples 1 to 8, Comparative Examples 1 to 3, and Reference Example were used in a dark place and a bright place (liquid crystal monitor peripheral illuminance of 400 lux). 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 multi-layer transparent substrate constituting the sensor film for touch panel is a laminate of a plurality of transparent substrates having a retardation of 3000 nm or more, and the slow phase of the multi-layer transparent substrate of the sensor film for touch panel The touch panel devices according to Examples 1 to 4 and 6 to 7 in which the direction of the axis and the absorption axis of the polarizing plate are in the range of 0 ° ± 30 ° or 90 ° ± 30 ° are visually observed in bright and dark places. It was excellent in evaluation. On the other hand, the touch panel device according to Example 5 in which the angle formed between the slow axis direction of the multilayer transparent substrate of the touch panel sensor film and the absorption axis of the polarizing plate was 45 ° is polarized light in a bright place. Although it was inferior to Nizimura evaluation through sunglasses, Nizimura evaluation in the dark is good and Nizimura can be suppressed to a practically preferable range. Moreover, it turns out that the effect similar to another Example can be acquired also in Example 8 which isolate | separated the transparent base material whose retardation is 3000 nm or more, and has arrange | positioned in several layers (2 places). In addition, although a reference example is an example about the case where the non-universal transparent base material which has a particularly high retardation value is used by single layer use, all the Examples of this invention are general-purpose transparent base materials. It can be seen that the same effect can be obtained regardless of whether these are used in combination.

(Modification)
The angle formed by the direction of the slow axis of the multilayer transparent substrate of the touch panel sensor 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 embodiments, the sensor film for a touch panel of the present invention and the touch panel device using the sensor film can extremely highly suppress the occurrence of nitrile on the screen, and can be applied to a touch panel device that requires high quality. I understand.

DESCRIPTION OF SYMBOLS 1 Touch panel apparatus 2 Transparent surface board 3 Sensor film for touch panels 30 Multilayer transparent base materials 301, 302 Transparent base materials 311, 312 Conductive pattern layer 33 Protective base material 34 Transparent adhesive layer 4 Polarizing plate 5 Color filter 6 Liquid crystal panel 61 Liquid crystal layer 62 Glass plate 7 Polarizing plate 8 Backlight

Claims (10)

A sensor film for a touch panel in which a conductive pattern layer is laminated on a multilayer transparent substrate formed by laminating a plurality of transparent substrates or between the layers of the multilayer transparent substrate,
The said transparent base material which comprises the said multilayer transparent base material is what has a retardation of 3000 nm or more, The sensor film for touchscreens characterized by the above-mentioned.   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 sensor film for a touch panel according to claim 1, wherein a difference (nx−ny) with respect to 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 sensor film for a touch panel according to claim 1 or 2, comprising any one material selected from the group consisting of, (meth) acrylonitrile resins, and cycloolefin resins. A sensor film for a touch panel according to any one of claims 1 to 3,
And a polarizing plate. A sensor film for a touch panel according to any one of claims 1 to 3,
A polarizing plate;
And a liquid crystal panel. The display device according to claim 5,
The angle formed between the absorption axis of the polarizing plate and the slow axis direction of the multilayer transparent substrate of the touch panel sensor film is arranged to be 0 ° ± 30 ° or 90 ° ± 30 °. A display device characterized by that.   The display device according to claim 5, wherein the liquid crystal panel is provided with a backlight whose primary light source is a white light emitting diode. A sensor film for a touch panel in which a conductive pattern layer is laminated on a transparent substrate,
A display device comprising a polarizing plate,
The display device further includes a functional layer configured to include the transparent substrate,
The display device, wherein both the sensor film for touch panel and the transparent substrate constituting the functional layer have a retardation of 3000 nm or more.   The display device according to claim 8, wherein the functional layer is a protective film disposed on an outermost surface on a display surface side of the display device.   The display device according to claim 8, wherein the functional layer is a scattering prevention film disposed on an outermost surface on a display surface side of the display device.

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