JP5673615B2 - Sensor film for touch panel and display device using the same - Google Patents

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. Transparent conductive materials such as ITO are generally used as transparent electrodes for touch panels, but in recent years, metal-patterned types have been studied, and substrates such as glass and transparent films are used. ing.

  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. This becomes more prominent especially when a plurality of sheets are laminated as the transparent base material of the sensor for touch panel.

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 a touch panel using such a polyester film. As a transparent substrate, the inventors obtained a relatively high retardation value. As a result of using the polyester film, the present inventors have found that the problem of Nizimura can be improved as compared with the case where a transparent substrate made of a conventional polyester film is used, and the present invention has been completed. More specifically, the present invention provides the following.

(1) on a transparent substrate, a touch panel sensor film conductive pattern layer is formed by laminating the transparent substrate all SANYO having the above retardation 6000 nm, wherein the transparent substrate is in the plane The difference (nx−ny) between the refractive index (nx) in the slow axis direction that is the direction with the largest refractive index and the refractive index (ny) in the fast axis direction that is orthogonal to the slow axis direction. , 0.05 or more, a sensor film for a touch panel.

( 2 ) 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) , 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.

( 3 ) The sensor film for a touch panel according to any one of (1) and (2) ,
And a polarizing plate.

( 4 ) The display apparatus provided with the sensor film for touchscreens as described in (1) or (2) , a polarizing plate, and a liquid crystal panel.

( 5 ) In the display device according to ( 4 ), an angle formed between the absorption axis of the polarizing plate and the slow axis of the transparent substrate of the sensor film for the touch panel is 0 ° ± 30 ° or 90 ° ±. A display device, wherein the display device is disposed at 30 °.

( 6 ) The display device according to ( 4 ) or ( 5 ), wherein the liquid crystal panel is provided with a backlight whose primary light source is a white light emitting diode.

  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. 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”.

  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 ° (cross). Nicole).

  As shown in FIG. 1, the touch-sensitive sensor film 3 includes a transparent base material 31, a transparent base material 32, and a protective base material 33, each of which is transparent adhesive from the surface side facing the transparent surface substrate 2 in the touch panel device 1. They are stacked via layers. As will be described in detail later, conductive pattern layers 311 (X direction) and 321 (Y direction) are formed on the back surfaces of the transparent base material 31 and the transparent base material 32, respectively.

  The transparent base materials 31 and 32 have a retardation of 6000 nm or more. If the retardation is less than 6000 nm, the display image of the touch panel device 1 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. 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.

  It is preferable that the retardation of the transparent base materials 31 and 32 is 10000-20000 nm from a viewpoint of nitrile prevention property and thin film formation.

  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).

  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 base materials 31 and 32 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 31 and 32 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 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). 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 a method for controlling the retardation of the transparent substrate produced by the above-described method to 6000 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 31 and 32 is appropriately determined according to the constituent materials 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 base materials 31 and 32 may not be 6000 nm or more, and the anisotropy of the mechanical properties becomes remarkable, and it is easy to cause tearing, tearing, etc., and practicality as an industrial material. 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 31 and 32 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 touch panel device 1 using such a touch panel sensor film 3 is also one aspect of the present invention.

  In the touch panel device 1, 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 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.

  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.

  Further, 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 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 transparent base materials 31 and 32 described above, even when such a monochromatic display is used, it is possible to suitably suppress the occurrence of nitjira.

  The touch panel device 1 may have a configuration in which a single layer and / or a plurality of layers are formed on the touch sensor film 3. 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.

  The conductive pattern layers 311 and 321 used for the sensor film 3 for the touch panel may be obtained by patterning a transparent conductive material layer formed on the transparent base materials 31 and 32. By patterning an opaque metal layer, the presence of openings 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 formation method, photolithography (etching), pattern printing, transfer, self-organization, and the like are applicable. As an example of the conductive pattern layer using etching, the transparent base materials 31 and 32 with copper foil laminated with an adhesive, or the transparent base materials 31 and 32 with ITO sputtered were etched into a predetermined pattern. Things. As a method of forming a conductive pattern layer by pattern printing, a method of printing a conductive ink in a predetermined pattern, a method of printing a material having a catalytic function of electroless plating in a predetermined pattern, and electroless plating of a conductive metal And a method of performing electroless plating treatment by adding a catalyst after printing a material for forming an adduct with an electroless plating catalyst. Examples of the conductive ink include silver paste, copper paste, and conductive polymer. Examples of the material having a catalytic function include ink containing catalyst particles such as palladium and particles having catalyst particles supported on the surface. Examples of the material that forms the adduct with the catalyst include ink containing silver or a conductive polymer. Examples of the metal forming the electroless plating layer include conductive metals such as copper, nickel, and silver. Although any method can be applied as the pattern printing method depending on the required pattern accuracy, screen printing, intaglio offset printing, a method of transferring from the intaglio using a UV curing primer, or the like is preferably used.

  In the touch panel device 1, the touch panel sensor is such that the angle formed by the slow axis of the transparent base materials 31 and 32 and the absorption axis of the polarizing plate 4 is in the range of 0 ° ± 30 ° or 90 ° ± 30 °. The film 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 °. More preferably, it is more preferably in the range of 0 ° ± 3 ° or 90 ° ± 3 °, and the sensor film 3 for the touch panel and the polarizing plate 4 are disposed so that the angle is 0 ° or 90 °. Most preferably. When the angle formed by the slow axis of the transparent base materials 31 and 32 and the absorption axis of the polarizing plate 4 is within the above range, it is possible to extremely highly suppress the occurrence of azimuth in the display image of the touch panel device 1. it can. 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 materials 31 and 32 is set to 6000 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 of the transparent substrates 31 and 32 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 of the transparent base materials 31 and 32 and the absorption axis of the polarizing plate 4 is not within the above range, nitrile occurs and the display quality deteriorates. Furthermore, 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 by the slow axis of the transparent base materials 31 and 32 and the absorption axis of the polarizing plate 4 is set. If it is not within the above-mentioned range, it is presumed that a discoloration will occur and the display quality will deteriorate. 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 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.

  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 direction of the slow axis of the transparent base materials 31 and 32 with respect to the absorption axis of the polarizing plate 4 is 45 °, the light transmittance is maximum, but the transmission Since the rate changes depending on the retardation of the transparent base materials 31 and 32 and the wavelength of transmitted light, an interference color (Nijimura etc.) 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.

  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.

  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>
[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 = 9900 nm, film thickness = 100 μm, and Δn = 0.099.
[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 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.
<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)
A touch panel device was produced in the same manner as in Example 1 except 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 30 °. .

Example 3
A touch panel device was produced in the same manner as in Example 1 except that the angle formed between 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 60 °. .

Example 4
A touch panel device was produced in the same manner as in Example 1 except 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 90 °. .

(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 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 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 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 and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(Example 11)
A touch panel device was produced in the same manner as in Example 9 except that the angle formed by the slow axis (average orientation angle) of the transparent substrate and the absorption axis of the polarizing plate on the viewer side of the liquid crystal monitor was 45 °. did.

(Example 12)
A touch panel device was produced in the same manner as in Example 1 except that the angle formed by the slow axis of the transparent substrate and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 45 °.

(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 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 and the absorption axis of the polarizing plate on the observer side of the liquid crystal monitor was 0 °.

(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 sensor film for touch panel is 6000 nm or more, and the slow axis of the transparent substrate of the sensor film for touch panel and the absorption axis of the polarizing plate are 0 ° ± 30. The touch panel device according to the example in the range of ° 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 and 12 in which the angle formed by the slow axis of the transparent substrate of the sensor film for the touch panel and the absorption axis of the polarizing plate was 45 ° is polarized sunglasses in a bright place. Although it was inferior to the evaluation of Nizimura over the night, the evaluation of Nizimura in the dark is good, and Nizimura can be suppressed to a practically preferable range.

  On the other hand, the touch panel device of the comparative example in which the retardation of the transparent base material of the sensor film for touch panel is less than 6000 was inferior to the visual evaluation of Nizimura in a bright place and a dark place.

  In addition, as for the transparent base material of the sensor film for touchscreens of the reference examples 1-2, all become 6.4 degrees or more in which the orientation angle difference of the slow axis direction of a transparent base material greatly exceeds a general value. In this case, it has been found that the effects of the present invention cannot always be achieved.

(Modification)
A touch panel prepared by the same method as in Example 1 except 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 is an arbitrary angle. As for the apparatus, it is possible to suppress Nizimura within a practically preferable range when used in a dark place.

  As described above, it can be understood from the examples that the sensor film for a touch panel of the present invention and the touch panel device using the same can be applied to a touch panel device that requires a very high quality and can prevent the occurrence of nitrile on the screen.

DESCRIPTION OF SYMBOLS 1 Touch panel apparatus 2 Transparent surface board 3 Sensor film for touch panels 31, 32 Transparent base material 311, 321 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 (6)

A sensor film for a touch panel in which a conductive pattern layer is laminated on a transparent substrate,
The transparent substrate may all SANYO having the above retardation 6000 nm,
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 touch panels , 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 sensor film for a touch panel according to claim 1, comprising any one material selected from the group consisting of: a (meth) acrylonitrile-based resin, and a cycloolefin-based resin. The sensor film for a touch panel according to claim 1 or 2 ,
And a polarizing plate. A sensor film for a touch panel according to any one of claims 1 and 2 ,
A polarizing plate;
And a liquid crystal panel. The display device according to claim 4 ,
The angle between the absorption axis of the polarizing plate and the slow axis of the transparent substrate of the sensor film for touch panel is set to be 0 ° ± 30 ° or 90 ° ± 30 °. Characteristic display device. Wherein the liquid crystal panel display device according to claim 4 or 5 backlight is provided a primary light source is a white light emitting diode.

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