JP4826007B2 - Touch panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminate having an antireflection function for the purpose of reducing reflection of light, an optical functional laminate using the laminate, and a display device such as a touch panel using the laminate.
[0002]
[Prior art]
Conventionally, in a CRT or the like, a multilayer film is coated by a vacuum deposition method or the like as a means for preventing reflection of the surface and a means for preventing the display screen from being charged. Furthermore, in the liquid crystal screen, irregular reflection is provided by providing irregularities on the surfaces thereof.
[0003]
As described in JP-A-11-224539, it has been proposed to provide a hard coat between the base material and the transparent conductive thin film as a countermeasure against cracks and peeling of the transparent conductive thin film caused by pen input on the touch panel. Yes.
[0004]
In recent years, portable terminals that are widely used are often used outdoors, and the need to provide an antireflection function is increasing. However, in general, the structure of the formed antireflection film has a slightly yellowish transmission color, the pen input type touch panel has poor pen input resistance of the antireflection laminate, and the acupressure input type is the best. There were problems such as poor surface antifouling properties.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and the object of the present invention is to prevent scratches due to pen input, etc., have sufficient mechanical strength characteristics, and provide anti-reflection function and fingerprints. An object of the present invention is to provide an antireflection laminate, an optical functional laminate, and a display device using the same, in which the transmission color for a display device such as a touch panel having excellent antifouling properties is colorless and transparent.
[0006]
[Means for Solving the Problems]
In order to solve these problems, the present invention provides a transparent conductive thin film having a pair of laminated bodies having a transparent conductive thin film layer and a transparent conductive thin film at a predetermined interval through a spacer. In the touch panel in which the layers are arranged to face each other, at least one panel has at least a base material and a TiO ₂ layer (optical film thickness = 67 nm) and an SiO ₂ layer (optical film ) on one surface on the base material. An antireflection laminate comprising an antireflection film in which a thickness = 32 nm), a TiO ₂ layer (optical thickness = 110 nm), and an SiO ₂ layer (optical thickness = 140 nm) are sequentially laminated from the substrate side ; A transparent conductive thin film layer provided on the surface of the base material on which the antireflection film is not provided, and the transmission color of the antireflection laminate in a standard light source C is represented by an L * a * b * system. When the value of b * is 1.5 or more 3 The touch panel is characterized by the following.
[0008]
The invention of claim 2 is the touch panel according to claim 1 , wherein the b * value when the transmitted color of the antireflection laminate in the standard light source C is expressed in the L * a * b * system is 1.5 or more and 2 .5 or less.
[0009]
According to a third aspect of the present invention, in the touch panel according to the first or second aspect , the substrate is a plastic film.
[0010]
The invention of claim 4 is the touch panel according to any one of claims 1 to 3 , wherein the antireflection laminate has a haze value of 1 or less formed between the base material and the antireflection film. It is characterized by having a clear hard coat layer and having a luminous reflectance Y value of 0.75 or less in the standard light source C.
[0011]
The invention according to claim 5 is the touch panel according to any one of claims 1 to 3 , wherein the antireflection laminate has a haze value of 5 or more formed between the base material and the antireflection film. has an antiglare hard coat layer is, luminous reflectance Y value in the standard light source C is equal to or more than 0.5.
[0012]
A sixth aspect of the present invention is the touch panel according to any one of the first to fifth aspects, wherein a corona treatment or a plasma treatment is performed on the surface of the substrate on which the antireflection film is formed or on the hard coat layer surface. and said that you have been subjected.
[0013]
A seventh aspect of the present invention is the touch panel according to any one of the first to fifth aspects, wherein a metal suboxide is formed on the surface of the base material on which the antireflection film is formed or the hard coat layer surface. Alternatively, a glue layer made of subnitride is formed.
[0014]
The invention of claim 8 is the touch panel according to any one of claims 1 to 7 , wherein an antifouling layer is formed on the outermost surface of the antireflection film.
[0015]
A ninth aspect of the invention is the touch panel according to any one of the first to eighth aspects, wherein a clear hard coat having a haze value of 1 or less is formed on the surface of the base material on which the antireflection film is not formed. A layer is formed .
[0017]
A tenth aspect of the present invention is the touch panel according to any one of the first to ninth aspects, wherein a corona treatment or a plasma is applied to the surface of the substrate on which the antireflection film is not formed or the hard coat layer surface. process is characterized in that characterized that you have been subjected.
[0018]
A thirteenth aspect of the present invention is the touch panel according to any one of the first to tenth aspects, wherein a metal suboxide is formed on the surface of the base material on which the antireflection film is not formed or on the hard coat layer surface . Alternatively, a glue layer made of subnitride is formed .
[0020]
<Action>
In the present invention, an antireflective film in which a high refractive index thin film layer and a low refractive index thin film layer made of a transparent ceramic or the like are alternately laminated is provided on one side of a substrate, and the transmitted color in the standard light source C is L *. When the value of b * when expressed in the a * b * system is 3 or less, more preferably 2.5 or less, it is possible to provide an antireflection laminate having a transparent transparent color.
[0021]
In the present invention, when the base material is a plastic film, an antireflection laminate that can be attached to a quadric surface can be provided.
[0022]
In the present invention, by forming a hard coat layer and / or a glue layer between a substrate and an antireflection film, an antireflection laminate having sufficient mechanical strength characteristics that can withstand daily use such as pen input is provided. Can be provided.
[0023]
In the present invention, by forming an antifouling layer on the outermost surface of the antireflection film, it is possible to provide an antireflection laminate that exhibits an antifouling effect, is unlikely to adhere fingerprints, and is easy to wipe off even if attached.
[0024]
In the present invention, by forming a transparent conductive thin film layer on the side opposite to the antireflection film of the antireflection laminate, an optical functional laminate that can be used for a member of a display device such as a touch panel having the above functions is provided. It is possible to provide a display device such as a touch panel using the optical functional laminate having the same function as described above.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of the layer structure of an antireflection laminate as one embodiment of the present invention. The antireflection laminate 10 of the present invention is a layer in which an antireflection film 13 formed by alternately laminating transparent high refractive index ceramic thin film layers 11 a and low refractive index ceramic thin film layers 11 b is laminated on one side of a substrate 12. Consists of configuration.
[0026]
Antireflection stack 10 of the present invention, the transmission color of the standard light source C, JIS Z8729 ^-1994 has been the L * a * b * b * values of 3 or less more preferably less when expressed in systems according to 2 By setting the thickness to 0.5 or less, it is possible to provide an antireflection laminate having a transparent transparent color.
[0027]
When the transmitted color is expressed in the L * a * b * system, b * increases when the transmittance near the wavelength of 550 nm is high, and b * decreases when the transmittance near the wavelength of 450 nm is high. In the antireflection laminate using a general ceramic thin film such as TiO ₂ or SiO _2, the transmittance in the long wavelength region of visible light is hardly attenuated. Therefore, when the b * value is large, the transmitted color becomes yellow.
By setting b * to 3 or less, the transmitted light of the antireflection laminate approaches colorless (transparent), and when it is further set to 2.5 or less, almost no yellowness is felt.
[0028]
As the base material 12 used in the present invention, it is only necessary to have transparency and a smooth surface. For example, polymethyl methacrylate, polycarbonate, polystyrene, polyethylene sulfide, polyethersulfone, polyolefin, polyethylene terephthalate, Examples thereof include polymer films such as polyethylene naphthalate and triacetyl cellulose, glass, and the like, which are appropriately selected according to the purpose and application.
[0029]
The material constituting the antireflection film 13 in the present invention is not particularly limited as long as it satisfies the relationship of the refractive index, whether it is an organic material or an inorganic material, but a ceramic thin film is preferable, and an oxide, sulfide, Materials such as fluoride and nitride can be used. The thin film made of the above-mentioned inorganic compound has a different refractive index depending on the material, and a plurality of ceramic thin films having different refractive indexes can be laminated to have a specific film thickness to form an antireflection film.
[0030]
Materials having a low refractive index include magnesium oxide (1.6), silicon dioxide (1.5), magnesium fluoride (1.4), calcium fluoride (1.3 to 1.4), cerium fluoride ( 1.6), aluminum fluoride (1.3), and the like.
Moreover, as a material with a high refractive index, titanium dioxide (2.4), zirconium dioxide (2.0), zinc sulfide (2.3), tantalum oxide (2.1), zinc oxide (2.1), Indium oxide (2.0) is mentioned. However, the numerical value in the parenthesis represents the refractive index.
[0031]
As a method for producing the ceramic thin film layer in the present invention, any film forming method may be used as long as the film thickness can be controlled. In particular, the dry method is excellent for producing a thin film. For this, a physical vapor deposition method such as a vacuum deposition method or a chemical vapor deposition method such as a CVD method can be used.
[0032]
FIG. 2 is a cross-sectional view showing the layer structure of another example of the antireflection laminate of the present invention. As shown in FIG. 2, the hard coat layer 24 and the glue layer 25 are sequentially laminated on the base material 22, and the transparent high refractive index ceramic thin film layer and the low refractive index ceramic thin film layer are alternately laminated on the glue layer 25. The antireflection film 23 is provided, and the antifouling layer 26 is provided on the outermost surface. The anti-reflection laminate of the present invention is not limited to the above layer configuration, and any one of the hard coat layer 24, the glue layer 25, the antifouling layer 26, or 2 thereof, depending on the purpose and application. For example, base material / hard coat layer / antireflection film, base material / hard coat layer / glue layer / antireflection film, base material / hard coat layer / antireflection film / antifouling layer, etc. It may be configured as follows.
[0033]
As the hard coat layer 24, there are two types, an anti-glare type, which can be roughly classified and can scatter reflected light by providing irregularities on the surface, etc., and can reduce the reflectance to some extent by itself. It is properly used depending on the application. A material that is transparent to the extent that it does not hinder the overall transparency can be used. For example, ultraviolet curable acrylic and the like can be mentioned. If the film thickness is 3 μm or more, sufficient strength is obtained, but a range of 5 to 20 μm is preferable from the viewpoint of transparency, coating accuracy and handling.
[0034]
In the antireflection laminate of the present invention, the clear hard coat layer having a haze value of 1 or less is formed between the substrate and the ceramic thin film layer, and the luminous reflectance Y value in the standard light source C is 0. 75 or less.
[0035]
The unevenness of the antiglare hard coat layer can be formed by mixing and dispersing transparent inorganic or organic ultrafine particles having an average particle diameter of about 0.01 to 3 μm. Alternatively, unevenness can be formed on the surface by embossing or the like. The ultrafine particles are not particularly limited as long as they are transparent, but a low refractive index material is preferable, and inorganic silicon oxide and magnesium fluoride are suitable in terms of stability, heat resistance, and the like. If the said hard-coat layer is apply | coated uniformly, it will not specifically limit as a coating method.
[0036]
In the antireflection laminate of the present invention, the antiglare hard coat layer having a haze value of 5 or more is formed between the substrate and the ceramic thin film layer, and the luminous reflectance Y value in the standard light source C is It is 0.5 or less.
[0037]
When the antireflection laminate of the present invention is used as a display device such as a touch panel, in order to improve the mechanical strength characteristics of the antireflection laminate for pen input, the adhesion between the base material or the hard coat and the ceramic thin film layer is improved. Therefore, it is preferable to subject the substrate or hard coat surface to corona treatment or plasma treatment.
[0038]
The glue layer 25 enhances the adhesion between the base material 22 or the hard coat layer 24 and the ceramic thin film layer of the antireflection film 23, and the material is particularly limited as long as it satisfies the adhesion specifications. is not. For example, a material made of a metal sub-oxide or sub-nitride is used, and a typical example is a material made of a metal sub-oxide such as chromium or silicon. The film thickness must be set so as not to disturb the transparency, and is preferably in the range of 5 to 20 nm.
[0039]
The antifouling layer 26 has water repellency and / or oil repellency, protects the surface of the ceramic thin film layer of the antireflection film 23, further enhances the antifouling property, and satisfies the required performance. In particular, the material is not limited. As a typical example, an organic compound, preferably a fluorine-containing organic compound is suitable. As a compound exhibiting water repellency, for example, a compound having a hydrophobic group is preferable, and fluorocarbon, perfluorosilane, and the like, and these polymer compounds are suitable. In order to improve antifouling by wiping off fingerprints, a polymer compound having oil repellency such as a methyl group is suitable.
[0040]
With these materials, the antifouling layer 26 can be formed by using various coating methods such as a vacuum film forming process such as a vacuum deposition method and a plasma CVD method, or a wet process such as a microgravure and a screen. . The film thickness must be set so as not to impair the function as the antireflection laminate, and is preferably 50 nm or less, more preferably 10 nm or less.
[0041]
FIG. 3 is a cross-sectional view showing a configuration of an example of the optical functional laminate of the present invention. The optical functional laminate 30 in which the transparent conductive thin film layer 37 is formed on the side opposite to the antireflection film 23 of the antireflection laminate 20 can be used as a member of a display device such as a touch panel. At this time, the structure in which the hard coat layer 34 and the glue layer 35 are formed between the base material 22 and the transparent conductive thin film layer 37 in order to prevent cracks in the transparent conductive thin film layer 37 is shown.
[0042]
Any one of the hard coat layer 34 and the glue layer 35, or both of them may be formed between the base material 22 and the transparent conductive thin film layer 37. When the glue layer 35 is not provided, it is preferable to perform corona treatment or plasma treatment on the surface of the base material 22 or the hard coat 34 on which the transparent conductive thin film layer 37 is laminated.
[0043]
The transparent conductive thin film layer 37 may be any one of indium oxide, zinc oxide, tin oxide, or two or three kinds of mixed oxides thereof, but various materials can be used depending on the purpose and application. It is not limited.
[0044]
FIG. 4 is a cross-sectional view illustrating a configuration of a touch panel as an example of the display device of the present invention. A panel composed of a pair of laminated bodies 30 and 50 each having a transparent conductive thin film layer is arranged with a predetermined interval therebetween with a predetermined interval therebetween via a spacer S so that the transparent conductive thin film layers 37 and 57 face each other. In the touch panel, one of the panels is the optical functional laminate 30 of the present invention.
[0045]
The touch panel is difficult to be damaged by pen input, has sufficient mechanical strength characteristics, and has excellent antifouling properties against reflection and fingerprints.
[0046]
【Example】
Next, the present invention will be described in detail with reference to FIG.
<Example 1>
UV curable clear acrylic hard coat layers 24 and 34 are applied to both sides of the PET film 75 μm of the transparent plastic substrate 22 in a thickness of 5 μm, and SiOx (x <2) is used as the glue layers 25 and 35. After forming the film with a thickness of 10 nm, TiO ₂ and SiO ₂ were laminated as the antireflection film 23, and further, 7 nm of fluoroalkylsilane was applied as the antifouling layer 26. The refractive index n and the optical film thickness nd of each layer of the ceramic thin film are:
First layer: TiO ₂ (n = 2.05 nd = 67 nm)
Second layer: SiO ₂ (n = 1.46 nd = 32 nm)
Third layer: TiO ₂ (n = 2.05 nd = 110 nm)
Fourth layer: SiO ₂ (n = 1.46 nd = 140 nm)
It was.
[0047]
The laminated body had optical characteristics of b * and luminous reflectance Y of the standard light source C of 1.5 and 0.7, respectively. Moreover, as a result of conducting a test of writing 100,000 characters in a 2 cm × 2 cm range with a load of 250 g using a touch pen, almost no scratches were observed and good results were obtained. Moreover, although the fingerprint was attached to the surface of the antireflection laminate, it was easily wiped off with a tissue paper.
[0048]
<Example 2>
UV curable clear acrylic hard coat layers 24 and 34 are applied to both sides of a 75 μm PET film of a transparent plastic substrate 22 in a film thickness of 5 μm, and the hard coat surface is 1 cm in an oxygen atmosphere of 1 Pa. after processing by rf plasma ² per 1W, the TiO ₂ and SiO ₂ are laminated as an anti-reflection film 23, further fluoroalkylsilane 7nm is formed by coating as an antifouling layer 26. The refractive index n and the optical film thickness nd of each layer of the ceramic thin film are:
First layer: TiO ₂ (n = 2.05 nd = 67 nm)
Second layer: SiO ₂ (n = 1.46 nd = 32 nm)
Third layer: TiO ₂ (n = 2.05 nd = 110 nm)
Fourth layer: SiO ₂ (n = 1.46 nd = 140 nm)
It was.
[0049]
The laminated body had optical characteristics of b * and luminous reflectance Y of the standard light source C of 1.5 and 0.7, respectively. Moreover, as a result of conducting a test of writing 50,000 characters in a 2 cm × 2 cm range with a load of 250 g using a touch pen, almost no scratches were observed, and good results were obtained. Moreover, although the fingerprint was attached to the surface of the antireflection laminate, it was easily wiped off with a tissue paper.
[0050]
<Example 3>
An ultraviolet curable antiglare type (haze 7) acrylic hard coat layer 24 is provided on one side of a 75 μm PET film of the transparent plastic substrate 22, and a clear acrylic hard coat layer 34 is provided on the opposite side of the base. Each of them is applied with a film thickness of 5 μm, and SiOx (x <2) is formed as a glue layer 25, 35 with a film thickness of 10 nm. Then, TiO ₂ and SiO ₂ are laminated as an antireflection film 23, and an antifouling layer 26 is formed. As a coating, 7 nm of fluoroalkylsilane was applied. The refractive index n and the optical film thickness nd of each layer of the ceramic thin film are:
First layer: TiO ₂ (n = 2.05 nd = 67 nm)
Second layer: SiO ₂ (n = 1.46 nd = 32 nm)
Third layer: TiO ₂ (n = 2.05 nd = 110 nm)
Fourth layer: SiO ₂ (n = 1.46 nd = 140 nm)
It was.
[0051]
The laminated body obtained optical characteristics with b * of the transmitted color and the luminous reflectance Y of 2.5 and 0.5 in the standard light source C, respectively. Moreover, as a result of conducting a test of writing 100,000 characters in a 2 cm × 2 cm range with a load of 250 g using a touch pen, almost no scratches were observed and good results were obtained. Moreover, although the fingerprint was attached to the surface of the antireflection laminate, it was easily wiped off with a tissue paper.
[0052]
Furthermore, a touch panel is prepared using an optical functional laminate in which a 500 Ω / □ ITO thin film is formed as a transparent conductive thin film 37 on the side opposite to the antireflection film of the base material, and a range of 2 cm × 2 cm using a touch pen. As a result of conducting a test of writing 100,000 characters under a load of 250 g, almost no scratches were observed as in the antireflection laminate, and good results were obtained.
[0053]
<Comparative Example 1>
UV curable clear acrylic hard coat layers 24 and 34 are applied to both sides of a 75 μm PET film of a transparent plastic substrate 22 to a thickness of 5 μm, and TiO ₂ and SiO ₂ are laminated as an antireflection film 23. Further, 7 nm of fluoroalkylsilane was applied and formed as the antifouling layer 26. The refractive index n and the optical film thickness nd of each layer of the ceramic thin film are:
First layer: TiO ₂ (n = 2.05 nd = 65 nm)
Second layer: SiO ₂ (n = 1.46 nd = 43 nm)
Third layer: TiO ₂ (n = 2.05 nd = 95 nm)
Fourth layer: SiO ₂ (n = 1.46 nd = 139 nm)
It was.
[0054]
The laminated body had optical characteristics with b * and luminous reflectance Y of 3.5 and 0.7 for the standard light source C, respectively, and the transmitted color was slightly yellow. Moreover, as a result of conducting a test of writing 100,000 characters in a 2 cm × 2 cm range with a load of 250 g using a touch pen, remarkable scratches due to peeling of the antireflection film were observed.
[0055]
【The invention's effect】
As described above, in the antireflection laminate provided with the antireflection film formed by alternately laminating the transparent high refractive index thin film layer and the low refractive index thin film layer on one side on the base material, the transmission color of the standard light source C is changed. By setting the value of b * when expressed in the L * a * b * system to be 3 or less, more preferably 2.5 or less, it becomes possible to provide an antireflection laminate having a transparent transparent color. .
[0056]
Moreover, it became possible to provide the antireflection laminated body which can be affixed on a secondary curved surface because a base material is a plastic film.
[0057]
In addition, by providing a hard coat layer and / or glue layer between the base material and the antireflection film, or by applying corona treatment / plasma treatment, sufficient mechanical strength characteristics to withstand daily use such as pen input It was possible to provide an antireflection laminate having the following.
[0058]
Further, by forming an antifouling layer on the outermost surface of the antireflection film, it has become possible to provide an antireflection laminate that is difficult to attach fingerprints and the like and that can be easily wiped off even if attached.
[0059]
In addition, a transparent conductive thin film is formed on the side opposite to the antireflection film of the antireflection laminate to form an optical functional laminate, and a display device such as a touch panel having the same function as described above is provided using the transparent conductive thin film. It became possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an example of an antireflection laminate of the present invention.
FIG. 2 is a cross-sectional view showing the structure of another example of the antireflection laminate of the present invention.
FIG. 3 is a cross-sectional view showing a configuration of an example of an optical functional laminate according to the present invention.
FIG. 4 is a cross-sectional view illustrating a configuration of an example of a touch panel as a display device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 20 ... Antireflection laminated body 11a, 21a ... High refractive index thin film layer 11b, 21b ... Low refractive index thin film layer 12, 22 ... Base material 13, 23 ... Antireflection film 24, 34 ... Hard coat layer 11
25, 35 ... glue layer 26 ... antifouling layer 30 ... optical functional laminate (panel)
37, 57 ... Transparent conductive thin film layer 40 ... Touch panel 50 ... Panel S ... Spacer

Claims (11)

In a touch panel in which a panel made of a pair of laminated bodies having a transparent conductive thin film layer is arranged so that the transparent conductive thin film layers face each other at a predetermined interval via a spacer,
At least one panel has at least a TiO ₂ layer (optical film thickness = 67 nm), an SiO ₂ layer (optical film thickness = 32 nm), and a TiO ₂ layer (optical film thickness = 110 nm) on one surface of the base material and the base material. ) And an SiO ₂ layer (optical film thickness = 140 nm) in order from the base material side, an antireflection laminate comprising the antireflection film, and a side of the base material on which the antireflection film is not provided It consists of a transparent conductive thin film layer provided on the surface,
The touch panel, wherein a b * value is 1.5 or more and 3 or less when a transmission color of the antireflection laminate in a standard light source C is represented by L * a * b * system. According to claim 1, wherein the value of b * of when the transparent color expressed in the L * a * b * system in the standard light source C of the antireflection laminate is 1.5 to 2.5 Touch panel . It said substrate, according to claim 1 or 2 The touch panel according to characterized in that it is a plastic film. The antireflection laminate has a clear hard coat layer having a haze value of 1 or less formed between the substrate and the antireflection film , and the luminous reflectance Y value of the standard light source C is 0. The touch panel according to any one of claims 1 to 3 , wherein the touch panel is 75 or less. The antireflection laminate has an antiglare hard coat layer having a haze value of 5 or more formed between the substrate and the antireflection film , and the luminous reflectance Y value in the standard light source C is the touch panel according to any one of claims 1 to 3, characterized in that more than 0.5. On the side surface or the hard coat layer surface forming the anti-reflection film of the substrate, according to claims 1, characterized that you corona treatment or plasma treatment is applied to any one of the 5 Touch panel . On the side surface or the hard coat layer surface forming the anti-reflection film of the substrate, from claim 1, wherein a glue layer made of a nitrous oxide or nitrous nitride of a metal is formed 5 The touch panel according to any one of the above. The touch panel according to any one of claims 1 7, characterized in that it antifouling layer is formed on the outermost surface of the antireflection film. On the side of the surface not to form an antireflection film of the base material, according to any one of claims 1 to 8, the value of the haze which is characterized in that 1 or less clear hard coat layer is formed Touch panel . On the side surface or the hard coat layer surface not to form an antireflection film of the substrate, from claim 1, characterized in that characterized that you corona treatment or plasma treatment is applied 9 The touch panel according to any one of the above items . On the side surface or the hard coat layer surface not to form an antireflection film of the substrate, from claim 1, wherein a glue layer made of a nitrous oxide or nitrous nitride of a metal is formed 10 The touch panel according to any one of the above .

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