JP2003196029A - Touch panel and liquid crystal display device with touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel capable of being easily manufactured and effectively preventing the diffused reflection to the incident light in a wide wavelength area, and to provide a liquid crystal display device with the touch panel capable of effectively preventing the diffused reflection to the incident light in the wide wavelength to improve the visibility. <P>SOLUTION: A first transparent board and a second transparent board having transparent conductive films on their surfaces are mounted at a constant interval in a state that the transparent conductive films are opposite to each other. The first transparent board includes a polymer having a positive inherent double refraction value and a polymer having a negative inherent double refraction value, and the touch panel satisfies Re(450)<Re(550)<Re(650) when the retardation values (Re) in wavelengths of 450 nm, 550 nm and 650 nm are respectively Re(450), Re(550), Re(650). The liquid crystal display device has the touch panel on the liquid crystal display. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a touch panel that effectively suppresses diffused reflection of incident light in a wide wavelength range, and a touch panel that effectively suppresses diffused reflection of incident light in a wide wavelength range. The present invention relates to a liquid crystal display device with a touch panel having excellent visibility.

[0002]

2. Description of the Related Art Touch panels are used for word processors, personal computers,
It has been used for liquid crystal displays of various devices such as mobile phones, digital cameras, video cameras, ticket vending machines, and the like. In a touch panel, two transparent conductive films provided on a transparent substrate are arranged to face each other via a spacer, and normally, the two transparent conductive films are insulated from each other. When a part of the surface is pressed, the two transparent conductive films come into contact with each other at the pressed position and a current flows, enabling image display, recording and the like.

By the way, conventionally, as a material of the transparent conductive film in the touch panel, a metal oxide represented by tin oxide / indium (ITO) or the like has been generally used. However, since the metal oxide or the like has a large refractive index, the surface of the touch panel on which the transparent conductive film is formed of the metal oxide or the like is easily reflected,
There is a serious problem that the visibility is poor due to the irregular reflection of light by the transparent conductive film.

Therefore, for example, Japanese Patent Laid-Open No. 2000-250
In Japanese Patent Laid-Open No. 016 etc., a touch panel in which a quarter wave plate is arranged on a transparent conductive film is proposed. In this touch panel, outside light of a certain specific wavelength is first transmitted through a polarizing plate to be linearly polarized light, then transmitted through a quarter wavelength plate to be circularly polarized light, and then reflected by a transparent conductive film, After passing through the / 4 wavelength plate, it becomes linearly polarized light again,
Since it is emitted from the polarizing plate to the outside, irregular reflection of incident light is effectively suppressed. However, in this case, diffuse reflection cannot be effectively suppressed for incident light in a wide wavelength range, that is, diffuse reflection cannot be suppressed for incident light of a wavelength other than the specific wavelength, and further, There is a problem that the structure is complicated and the manufacture is not easy.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and achieve the following objects. That is, the present invention is easy to manufacture, a touch panel that effectively suppresses diffused reflection of incident light in a wide wavelength range, and a touch panel that effectively suppresses diffused reflection of incident light in a wide wavelength range. An object of the present invention is to provide a liquid crystal display device with a touch panel having excellent visibility.

[0006]

Means for solving the above-mentioned problems are as follows. That is, <1> a first transparent substrate having a transparent conductive film on its surface and a second transparent substrate are arranged such that the transparent conductive films face each other with a constant space therebetween, and the first transparent substrate is A polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, and having a wavelength of 450 nm or 550
retardation value (R
e) is Re (450), Re (550), Re
If (650), then Re (450) <Re (550)
<Re (650), which is a touch panel. <2> The touch panel according to <1>, which has a polarizing plate on a surface of the first transparent substrate opposite to the transparent conductive film. <3> The first transparent substrate is 0.2 ≦ Re (450) / 4
50 (nm) ≦ 0.3, 0.2 ≦ Re (550) / 55
0 (nm) ≤ 0.3 and 0.2 ≤ Re (650) /
<1> or <2, which satisfies 650 (nm) ≦ 0.3
> Is the touch panel. <4> The first transparent substrate according to any one of <1> to <3>, wherein the first transparent substrate is formed of a polymer blend of a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value. It is a touch panel. <5> Any one of the above <1> to <3>, wherein the first transparent substrate is formed by laminating a layer made of a polymer having a positive intrinsic birefringence value and a layer made of a polymer having a negative intrinsic birefringence value. The touch panel described in 1. <6> The touch panel according to <5>, wherein a slow axis of a layer made of a polymer having a positive intrinsic birefringence value and a slow axis of a layer made of a polymer having a negative intrinsic birefringence value are orthogonal to each other. . <7> The touch panel according to any one of <1> to <6>, wherein the polymer having a positive intrinsic birefringence value is a cycloolefin resin. <8> The touch panel according to any one of <1> to <7>, wherein the polymer having a negative intrinsic birefringence value is a styrene resin. <9> A first transparent substrate, a first layer formed of norbornene resin having a positive intrinsic birefringence value, and a second layer formed of styrene maleic anhydride resin having a negative intrinsic birefringence value, A third layer formed of a norbornene resin having a positive intrinsic birefringence value is laminated in this order so that the orientation directions thereof coincide with each other, and between the first layer and the second layer and Formed between the second layer and the third layer with a hot-melt resin having a softening point lower than the glass transition point (Tg) of the norbornene resin and the glass transition point (Tg) of the styrene maleic anhydride resin. The touch panel according to the above items <5> to <8>, which includes the adhered adhesive layer. <10> The above <1>, wherein the second transparent substrate is a glass substrate.
To <9>. <11> A liquid crystal display device with a touch panel, comprising the touch panel according to any one of <1> to <10> above on a liquid crystal display.

In the present invention, the following means are preferable. <12> The touch panel according to any one of <1> to <10>, in which the first transparent substrate and the second transparent substrate are arranged via a spacer. <13> The touch panel according to <5>, wherein the lamination is performed by coextrusion. <14> The touch panel according to <7>, wherein the cycloolefin resin is a norbornene resin. <15> The touch panel according to <8>, wherein the styrene resin is a styrene maleic anhydride resin. <16> The above-mentioned <15> in which the mass composition ratio of styrene constituting the styrene-maleic anhydride resin and maleic anhydride (styrene: maleic anhydride) is 95: 5 to 50:50.
> Is the touch panel. <17> Glass transition point of norbornene resin (NB (T
g)) and the glass transition point (St (Tg)) of the styrene-maleic anhydride resin is NB (Tg) -10 ° C ≤ S
<9 satisfying t (Tg) ≦ NB (Tg) + 10 ° C.
> And the touch panel according to any one of <12> to <13>. <18> The touch panel according to any one of <1> to <9> and <12> to <17>, wherein the photoelasticity of the first transparent substrate is 10 Brewster or less. <19> The three-axis direction refractive indexes of the first layer and the third layer are Nx, Ny, and Nz, respectively, and 3 in the second layer is used.
Assuming that the axial refractive indices are nx, ny, and nz, respectively, the following equation: 0.5 <(Nx-Nz) / (Nx-Ny) <
1.5, 0.5 <(nx-ny) / (nx-ny) <
<9> and <12> to <18> satisfying 1.5
The touch panel according to any one of 1. <20> Retardation value (R of the first layer and the third layer at a wavelength of 550 nm based on the stretching axis direction (R
e) is 400 to 800 nm in total, and the retardation value (Re) in the second layer is -660 to -260n.
The touch panel according to any one of <9> and <12> to <19>, which has a retardation value (Re) of 100 to 160 nm in the first transparent substrate. <21> The touch panel according to <9>, wherein the adhesion layer is formed of a hot melt resin. <22> The softening point of the hot melt resin is lower than the glass transition point (Tg) of the polymer having a positive intrinsic birefringence value and the glass transition point (Tg) of the polymer having a negative intrinsic birefringence value. It is the touch panel according to <21>.

In the touch panel according to <1>, the first transparent substrate and the second transparent substrate having the transparent conductive film on the surface are arranged so that the transparent conductive films face each other with a constant gap. Normally, the two transparent conductive films are insulated from each other, and when a part of the touch panel surface is pressed, the two transparent conductive films come into contact with each other at the pressed position and can be energized. Becomes In the touch panel, the first transparent substrate is Re (450) <Re (55
0) <Re (650), which is a wideband wavelength plate, so that even if external light of an arbitrary wavelength is incident on the touch panel, the external light passes through the first transparent substrate that is the wideband wavelength plate. Then, it becomes circularly polarized light, etc., is reflected by the transparent conductive film, is transmitted through the broadband wavelength plate, becomes linearly polarized light, etc., and is emitted to the outside. Therefore, diffused reflection is effectively suppressed regardless of the wavelength of incident light. .

In the touch panel according to <2>, since the polarizing plate is provided on the surface of the first transparent substrate opposite to the transparent conductive film in <1>, the touch panel has an arbitrary wavelength. Even when external light of the above is incident, the external light is first converted into linearly polarized light by the polarizing plate, the linearly polarized light is transmitted through the first transparent substrate that is the broadband wavelength plate to become circularly polarized light, and the transparent light is transmitted. Since the light is reflected by the conductive film, passes through the broadband wavelength plate, becomes linearly polarized light, and is emitted from the polarizing plate to the outside as linearly polarized light, diffused reflection is effectively suppressed regardless of the wavelength of incident light.

In the touch panel according to <3>, in the <1> or <2>, the first transparent substrate has 0.2 ≦
Re (450) / 450 (nm) ≦ 0.3, 0.2 ≦ R
e (550) / 550 (nm) ≦ 0.3 and 0.2
Since it is a wideband quarter-wave plate satisfying ≦ Re (650) / 650 (nm) ≦ 0.3, even if external light of an arbitrary wavelength is incident on the touch panel, the external light is first converted into the polarized light. It is converted into linearly polarized light by the plate, and the linearly polarized light is
Circularly polarized light through the first transparent substrate, which is a four-wave plate,
Then, the light is reflected by the transparent conductive film, passes through the broadband quarter-wave plate, becomes linearly polarized light, and is emitted as linearly polarized light to the outside from the polarizing plate. Therefore, irregular reflection is effectively suppressed regardless of the wavelength of incident light. To be done.

In the touch panel according to <4> above, in any one of <1> to <3>, the first transparent substrate is a polymer having a positive intrinsic birefringence value and a negative intrinsic birefringence value. Since it is formed of a polymer blend with a polymer, the first transparent substrate functions as a broadband wave plate even if it has a single layer structure.

In the touch panel according to <5> above, in any one of <1> to <3>, the first transparent substrate has a layer made of a polymer having a positive intrinsic birefringence value and an intrinsic birefringence value. The first transparent substrate functions as a broadband wave plate due to the laminated structure because it is laminated with a layer made of a negative polymer.

The touch panel according to <6> is the touch panel according to <5>, in which the slow axis of the layer made of a polymer having a positive intrinsic birefringence value and the polymer having a negative intrinsic birefringence value. Since the slow axes of the layers are orthogonal to each other, the wavelength dispersion of the retardation (Re) that the two layers independently exhibit is reduced, the retardation (Re) on the short wavelength side is small, and the long wavelength is long. The retardation (Re) on the side can be increased, and as a result,
In the first transparent substrate, the ratio of the retardation Re (λ) at the wavelength λ to the wavelength (Re (λ) / λ) can be made substantially constant over the entire visible light range, and as a result, the first transparent substrate can be obtained. The substrate effectively functions as a broadband wave plate having substantially uniform retardation characteristics with respect to incident light in the entire visible light range. Further, the two layers can inevitably have their slow axes orthogonal to each other if the stretching directions are made coincident with each other, and in this case, the production is easy.

In the touch panel according to <7>, in any one of <1> to <6>, the polymer having a positive intrinsic birefringence value is a cycloolefin resin, and the touch panel according to <8>. Is from <1> to <7>
In any one of the above, since the polymer having a negative intrinsic birefringence value is a styrene resin, the first transparent substrate has excellent light transmittance characteristics, heat resistance, dimensional stability, photoelastic characteristics, and the like,
Effectively functions as a broadband wave plate.

In the touch panel according to <9> above, in any one of <5> to <8>, the first transparent substrate has a first layer, a second layer, and a third layer in this order in the alignment direction. Since the three layers are laminated so that they coincide with each other, the wavelength dispersion of the retardation (Re) shown by each of the three layers is mutually reduced, and as a result, the first transparent substrate is applied to incident light in the entire visible light range. As a result, it effectively functions as a broadband wave plate having a substantially uniform phase difference characteristic. Further, since the adhesion layer is provided between the first layer and the second layer and between the second layer and the third layer, the first transparent substrate can be handled as one member. Yes, it is convenient.

In the touch panel according to <10>, since the second transparent substrate is a glass substrate in any one of <1> to <9>, when the first transparent substrate is pressed,
Following the pressing, the second transparent substrate does not bend and malfunctions are small.

The liquid crystal display device with a touch panel according to <11> has the touch panel according to any one of <1> to <10> on a liquid crystal display.
Normally, there is insulation between the two transparent conductive films,
When a part of the surface of the touch panel is pressed, the two transparent conductive films come into contact with each other at the pressed position and a current flows, and image display / recording or the like becomes possible. Even when external light having an arbitrary wavelength is incident on the liquid crystal display device with a touch panel, the external light is transmitted through the first transparent substrate to become circularly polarized light or the like, and then reflected by the transparent conductive film to form the first transparent substrate. Since it is transmitted to the outside and becomes linearly polarized light or the like and is emitted to the outside, irregular reflection is effectively suppressed regardless of the wavelength of incident light. Therefore, in the liquid crystal display device with a touch panel, diffused reflection from the screen is effectively suppressed, and the visibility is excellent.

In the touch panel according to <12>, in any one of the above <1> to <10>, a first transparent substrate and a second transparent substrate are arranged via a spacer. Since the second transparent substrate and the second transparent substrate are always arranged at a constant interval, there is little malfunction.

In the touch panel according to <13> above, in <5> above, the lamination is performed by coextrusion, so that operations such as delicate and complicated angle adjustment at the time of chip cutting of the stretched film and bonding of the chips can be performed. It is unnecessary and can be manufactured by a simple process.

In the touch panel according to <14>, the cycloolefin resin is norbornene resin in <7>, and the touch panel according to <15> is
In the above <8>, since the styrene-based resin is a styrene-maleic anhydride resin, the first transparent substrate is excellent in light transmittance characteristics, heat resistance, dimensional stability, photoelastic characteristics, etc. It works effectively.

In the touch panel according to <16>, the mass composition ratio of styrene and maleic anhydride (styrene: maleic anhydride) constituting the styrene-maleic anhydride resin is 95: 5 to 50 in <15>. : 50, the glass transition point (Tg) of the styrene-maleic anhydride resin can be adjusted to about 108 ° C. or higher, and the glass transition point (Tg) of the norbornene resin and the adhesive layer forming the adhesive layer can be adjusted. Can reduce the difference from the softening point of hot melt resins

In the touch panel according to <17> above, in any of <9> and <12> to <13>, the glass transition point (NB (Tg)) of the norbornene resin.
And glass transition points of styrene maleic anhydride resin (St
(Tg)) is expressed by the following equation: NB (Tg) −10 ° C. ≦ St (T
Since g) ≦ NB (Tg) + 10 ° C. is satisfied, manufacturing is easy.

In the touch panel according to <18>, the photoelasticity of the first transparent substrate is 10 Brewster or less in any one of <1> to <9> and <12> to <17>. There is no decrease in contrast due to birefringence.

In the touch panel described in <19>, in any one of <9> and <12> to <18>, the triaxial direction refractive indexes of the first layer and the third layer are respectively Nx, Ny, and When Nz and the three-axis direction refractive indices in the second layer are nx, ny, and nz, respectively,
0.5 <(Nx-Nz) / (Nx-Ny) <1.5,
Since 0.5 <(nx-nz) / (nx-ny) <1.5 is satisfied, the viewing angle dependency is small. That is, the retardation (Re) is represented by the product of birefringence (Δn) and thickness (d), and the optical waveguide length of incident light in the normal direction to the layer is d.
On the other hand, the optical waveguide length of the incident light in the direction inclined by the angle θ from the normal direction is longer than d, and the latter case has a larger retardation (Re) than the former case. . However, in the touch panel, the above formula is satisfied, and as the angle θ increases, the birefringence (Δ
Since n) becomes small, the retardation (Re) is maintained constant regardless of the angle of incident light, the viewing angle dependency is small, and the visibility is excellent.

In the touch panel according to <20>, in any one of the above <9> and <12> to <19>, the wavelengths of the first layer and the third layer at a wavelength of 550 nm are based on the stretching axis direction. The total retardation value (Re) is 400 to 800 nm, the retardation value (Re) in the second layer is −660 to −260 nm, and the retardation value (R in the first transparent substrate is
Since e) is 100 to 160 nm, the wavelength dispersion of the retardation (Re) shown by each of the three layers is mutually reduced, and as a result, the first transparent substrate is effective for incident light in the entire visible light range. Wide band 1 / with nearly uniform phase difference
Effectively functions as a four-wave plate.

In the touch panel according to <21> above, in <9> above, since the adhesion layer is formed of the hot-melt resin, the layers can be easily laminated by heating without delamination. .

In the touch panel according to <22>, the softening point of the hot melt resin is the same as in <21>.
Since the glass transition point (Tg) of the polymer having a positive intrinsic birefringence value and the glass transition point (Tg) of the polymer having a negative intrinsic birefringence value are lower, the retardation (Re ) Is suppressed and it is easy to optimize chromatic dispersion characteristics.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION (Touch panel) In a touch panel of the present invention, a first transparent substrate and a second transparent substrate having a transparent conductive film on the surface thereof are arranged with a certain space therebetween so that the transparent conductive films face each other. The first transparent substrate contains a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, and the wavelength is 450 nm, 55
Retardation value at 0 nm and 650 nm (R
e) is Re (450), Re (550), Re
If (650), then Re (450) <Re (550)
<Re (650) is satisfied. That is, the touch panel of the present invention is not particularly limited in the known touch panel configuration, except that one of the two transparent substrates on which the transparent conductive film is formed is the first transparent substrate satisfying the above conditions. The same structure as the touch panel of can be adopted.

-First transparent substrate- The first transparent substrate has a transparent conductive film on its surface.

The material of the transparent conductive film is not particularly limited and may be appropriately selected from known conductive materials, and examples thereof include metal oxides or oxide semiconductors and conductive polymers. .

Examples of the metal oxide or oxide semiconductor include tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO) and the like. Examples of the conductive polymer include polyaniline, polythiophene, polypyrrole, and the like. The material of the transparent conductive film may be used alone or in combination of two or more. Among these, metal oxides or oxide semiconductors are preferable, and indium tin oxide (ITO) is particularly preferable in terms of productivity, high conductivity, transparency, and the like.

The thickness of the transparent conductive film is not particularly limited and can be appropriately selected depending on the materials and the like, but is usually 10 nm to 5 μm.

The method for forming the transparent conductive film is not particularly limited and may be appropriately selected depending on the material. For example, electron beam method, sputtering method, resistance heating vapor deposition method, chemical reaction method (sol-method). Gel method, etc., and the like.

The first transparent substrate contains a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value.

The polymer having a positive intrinsic birefringence value is
When light is incident on a layer formed by taking molecules in a uniaxial orientation, it means a polymer in which the refractive index of light in the orientation direction is larger than the refractive index of light in the direction orthogonal to the orientation direction, The polymer having a positive intrinsic birefringence value is not particularly limited as long as it is a material having the property of exhibiting optically positive uniaxiality when a uniaxial orientation rule is given to the molecule, and is appropriately selected according to the purpose. For example, a resin, a rod-shaped liquid crystal, a rod-shaped liquid crystal polymer or the like can be used. They are,
They may be used alone or in combination of two or more. Of these, resins are preferable.

Examples of the resin include cycloolefin resin, polyolefin resin (eg, polyethylene, polypropylene, norbornene-based polymer), polyester resin (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyarylene sulfide resin (eg, Polyphenylene sulfide, etc.), polyvinyl alcohol resin, polycarbonate resin, polyarylate resin, cellulose ester resin,
Examples thereof include polyether sulfone resin, polysulfone resin, polyallyl sulfone resin, polyvinyl chloride resin, and multi-component (binary, ternary, etc.) copolymers thereof. Among these, cycloolefin resins are preferable in terms of light transmittance characteristics, heat resistance, dimensional stability, photoelastic characteristics and the like.

Suitable examples of the cycloolefin resin include norbornene resin. Among these, norbornene resin is particularly preferable because it is excellent in light transmittance characteristics, heat resistance, dimensional stability, and photoelastic characteristics.

The norbornene resin is not particularly limited and may be appropriately selected depending on the purpose. However, the thermoplastic norbornene resin is excellent in transparency, low water absorption, heat resistance and suitable for optical applications. Is preferred.

The above-mentioned thermoplastic norbornene resin has a norbornane skeleton as a repeating unit, and specific examples thereof include JP-A-60-168708, JP-A-62-252406 and JP-A-62-62. 252407
JP-A No. 2-133413, JP-A No. 63-
145324, JP-A-63-264626, JP-A-1-240517, and JP-B-57-88.
No. 15, JP-A-5-39403, and JP-A-5-39403.
No. 43663, No. 5-43834, No. 5-70655, No. 5-279554, No. 6-206985, No. 7-620.
28, JP-A-8-176411, JP-A-9
Those described in, for example, JP-A-241484. These may be used alone or in combination of two or more.

In the present invention, among the above-mentioned thermoplastic norbornene resins, those having a repeating unit represented by any of the following structural formulas (I) to (IV) are preferable.

[0041]

[Chemical 1]

In the above structural formulas (I) to (IV), A,
B, C and D represent a hydrogen atom or a monovalent organic group.

Further, among the above-mentioned thermoplastic norbornene resins, at least one tetracyclododecene represented by the following structural formula (V) or (VI) and an unsaturated cyclic compound copolymerizable therewith are used. A hydrogenated polymer obtained by hydrogenating a polymer obtained by metathesis polymerization is also preferable.

[0044]

[Chemical 2]

In the structural formula (V) or (VI),
A, B, C and D represent a hydrogen atom or a monovalent organic group.

The weight average molecular weight of the norbornene resin is about 5,000 to 1,000,000,
8,000 to 200,000 is preferable.

The norbornene resin may be appropriately synthesized or may be a commercially available product, and examples of the commercially available product include "Arton" manufactured by JRS Co., Ltd. and Zeon Corporation. "Zeonex" and "Zeonor", and "APO" manufactured by Mitsui Petrochemical.

When the norbornene resin is used as the polymer having a positive intrinsic birefringence value, the polymer having a negative intrinsic birefringence value is preferably one having a large wavelength dispersion of its intrinsic birefringence value. Wavelength 4
When the intrinsic birefringence values (Δn) at 50 nm and wavelength 550 nm are Δn (450) and Δn (550), respectively, the following equation: | Δn (450) / Δn (550) | ≧ 1.02,
Satisfying the following formula, | Δn (450) / Δ
Those satisfying n (550) | ≧ 1.05 are more preferable. The upper limit of | Δn (450) / Δn (550) | is preferably large, but in the case of resin, it is generally 2.0 or less.

As the rod-shaped liquid crystal, a liquid crystal exhibiting a rod-shaped nematic orientation is preferably mentioned, and it may be a low-molecular liquid crystal or a high-molecular liquid crystal. Examples of the low-molecular liquid crystal include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenylesters, cyanophenylcyclohexanes, cyano-substituted phenylpyridines, phenyldioxanes. , Tolans, alkenylcyclohexylbenzonitriles, and the like are preferable.

The polymer having a negative intrinsic birefringence value is
When light is incident on a layer formed by taking a uniaxial orientation of molecules, it means a polymer in which the refractive index of light in the orientation direction is smaller than the refractive index of light in the direction orthogonal to the orientation direction, The polymer having a negative intrinsic birefringence value is not particularly limited as long as the optical properties of the molecule exhibit a negative uniaxial property when the molecules are oriented in a uniaxial order, and may be appropriately selected according to the purpose. Examples thereof include styrene resins, acrylonitrile resins, methyl methacrylate resins, and cellulose ester resins. These may be used alone or in combination of two or more. Of these, styrene resins are preferable.

Preferred examples of the styrene-based resin include polystyrene resins and styrene copolymers of styrene or a styrene derivative and at least one selected from acrylonitrile, maleic anhydride, methyl methacrylate and butadiene. To be Examples of the styrene copolymer include styrene maleic anhydride resin, styrene / acrylonitrile resin, and styrene / methyl methacrylate resin. Among these, styrene maleic anhydride resin is particularly preferable. Incidentally, as a commercial product of the styrene maleic anhydride resin,
For example, "Dylark D332" manufactured by Nova Chemicals
And so on.

The mass composition ratio of styrene and maleic anhydride constituting the styrene maleic anhydride resin (styrene: maleic anhydride) is 95: 5 to 50:50.
Is preferred, and 90:10 to 70:30 is more preferred.
When the mass composition ratio is within the above numerical range, the glass transition point (Tg) of the styrene maleic anhydride resin is about 108.
This is advantageous in that the temperature can be adjusted to not lower than 0 ° C., and the difference between the glass transition point (Tg) of the norbornene resin and the softening point of the hot melt resin forming the adhesion layer can be reduced.

The glass transition point "Tg" of a polymer having a positive intrinsic birefringence value and the glass transition point (Tg) of a polymer having a negative intrinsic birefringence value are represented by the following equation: "Tg"-
It is preferable to satisfy 10 ° C. ≦ (Tg) ≦ “Tg” + 10 ° C., and the following equation, “Tg” −5 ° C. ≦ (Tg) ≦ “Tg” +
It is more preferable that the temperature is 5 ° C., and “Tg” and (Tg)
It is particularly preferable that and are substantially the same.

The first transparent substrate contains a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, but its mode is not particularly limited and may be selected depending on the purpose. Can be appropriately selected, for example, a mode in which a polymer blend of a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, a polymer having a positive intrinsic birefringence value And a layer made of a polymer having a negative intrinsic birefringence value.

In the case where the first transparent substrate is formed of the polymer blend, the blending ratio of the polymer having a positive intrinsic birefringence value and the polymer having a negative intrinsic birefringence value is both polymers. The absolute value of the intrinsic birefringence value in, and the expression of birefringence at the molding temperature, and the like cannot be specified unconditionally. The polymer having a negative value) is preferably 5: 5 to 9: 1, more preferably 7: 3 to 8: 2.

In the case where the first transparent substrate is formed by the lamination, the lamination method is not particularly limited and can be appropriately selected according to the purpose. For example, the intrinsic birefringence value is A method of separately preparing and laminating a layer made of a polymer having a positive value and a layer made of a polymer having a negative value of the intrinsic birefringence value, the polymer having a positive value of the intrinsic birefringence value and the negative value of the intrinsic birefringence value A method of coextruding with a polymer,
And so on.

Of these, the coextrusion method is particularly preferable because it is not necessary to consider the compatibility of the materials, the range of material selection is wide, the cost is low, and the manufacturing work is simple and efficient. The method of coextrusion is, for example,
It can be performed by introducing a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value into one die and extruding the die.

In the case where the first transparent substrate is formed by the lamination, a layer made of a polymer having a positive intrinsic birefringence value and a layer made of a polymer having a negative intrinsic birefringence value are mutually delayed. It is preferable that the phase axes are orthogonal to each other. The retardation (Re) of the first transparent substrate is
Retardation (Re) between the polymer having a positive intrinsic birefringence value and the polymer having a negative intrinsic birefringence value
Therefore, by laminating a layer made of a polymer having a positive intrinsic birefringence value and a layer made of a polymer having a negative intrinsic birefringence value with their slow axes orthogonal to each other, The wavelength dispersions of the retardations (Re) that the layers independently show can be mutually reduced, the retardation (Re) on the short wavelength side of the first transparent substrate can be made small, and the retardation (Re) on the long wavelength side can be reduced. As a result, the ratio of the retardation Re (λ) at the wavelength λ of the first transparent substrate to the wavelength (Re (λ) /
λ) is kept almost uniform with respect to the incident light in the entire visible light,
The first transparent substrate can effectively function as a broadband wavelength plate having a substantially uniform retardation property in the entire visible light range.

The method of making the slow axes of the two layers orthogonal to each other is not particularly limited, but in the case of the coextrusion method, the two layers are coextruded and laminated and then stretched. Since the slow axes can easily be made orthogonal to each other just by performing (just matching the stretching directions), it is necessary to perform operations such as chip cutting of the stretched film and subtle and complicated angle adjustment when bonding the chips. It can be manufactured by a simple process.

The retardation (Re) in the first transparent substrate is a mass ratio of a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, a stretching temperature and a stretching rate. It can be adjusted to a desired range by appropriately selecting the stretching conditions such as the above and performing the stretching using a stretching machine. As the stretching machine, for example, a longitudinal uniaxial stretching machine that stretches in the mechanical flow direction, a tenter stretching machine that stretches in the direction orthogonal to the mechanical flow direction, a biaxial stretching machine that can control the thickness direction, and the like are preferable. Are listed in. The stretching temperature is (Tg _min −20) ° C., where Tg _min is the minimum glass transition temperature of the basic material (the polymer having the positive intrinsic birefringence value and the polymer having the negative intrinsic birefringence value).
It is preferable to set the temperature to (Tg _min ) ° C.

In the case where the first transparent substrate is formed by the layered structure, it has one layer of a polymer having the positive intrinsic birefringence value and one layer of a polymer having the negative intrinsic birefringence value. However, it may have another layer for the purpose of improving the physical properties of the first transparent substrate.

The other layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the layer in which the first transparent substrate has symmetry in its cross section is preferable. As such a layer, the first transparent substrate,
When the layer formed of a polymer having a positive intrinsic birefringence value, a layer made of a polymer having a negative intrinsic birefringence value, and a layer made of a polymer having a positive intrinsic birefringence value Corresponds to a layer of a polymer having a positive intrinsic birefringence value, and is formed of a polymer having the same sign as the intrinsic birefringence value of the polymer forming the layer at a symmetrical position in the cross section of the first transparent substrate. Preferred layers are preferred.

In a preferred specific example in the case where the first transparent substrate is formed by the above-mentioned lamination, a first layer formed of the norbornene resin and a second layer formed of the styrene-maleic anhydride resin are preferred. And a third layer formed of the norbornene resin are laminated in this order in such a manner that the orientation directions thereof are aligned with each other, and between the first layer and the second layer and between the second layer and the second layer. Preferable examples are those having a three-kind five-layer structure having an adhesion layer between the third layer and the third layer.

The adhesion layer is not limited to the case of the three-kind five-layer structure, but can be appropriately formed in each mode in which the first transparent substrate is formed by the lamination. As the material of the adhesion layer, a layer made of a polymer having the positive intrinsic birefringence value, a layer having good adhesion to the polymer layer having a negative intrinsic birefringence value, or the like may be used, and hot melt Suitable examples include resin.

The hot melt resin is not particularly limited and may be appropriately selected according to the purpose.
Those having a softening point lower than the glass transition point (Tg) of the norbornene resin and the glass transition point (Tg) of the styrene-maleic anhydride resin are preferable, and those having a softening point lower by 10 ° C. or less are more preferable. Those having a low softening point of not higher than 0 ° C. are particularly preferable, and specifically, a polyolefin resin is more preferable. When the softening point is higher than the glass transition point (Tg) of the norbornene resin and the glass transition point (Tg) of the styrene-maleic anhydride resin, retardation (Re) develops in the adhesion layer during stretching, and the wavelength While it may be difficult to optimize the dispersion characteristics, if it is within the above range, such a situation does not occur. The softening point can be measured, for example, by a Bigatt softening point according to ASTM D1525.

The hot melt resin may be appropriately synthesized or may be a commercially available product. Examples of the commercially available products include "Admer", Mitsui. "CMP" made by DuPont Polychemical
S "," Asahi Melt "manufactured by Asahi Melt, A.C.
"Hot Melt" made by i Limited, "EC Series" made by Sumitomo 3M, "Esdyne" made by Sekisui Chemical, "Meltron" made by Diabond, "Nittite" made by Nitta Gelatin, Nogawa Examples include "Diabond" manufactured by Chemical Co., Ltd., and "Hirodine" manufactured by Hirodyne Industry Co., Ltd.

In the case of the above-mentioned three-kind five-layer structure, the triaxial refractive indexes of the first layer and the third layer are respectively Nx,
When Ny and Nz are set and the triaxial directions of the second layer are set to nx, ny and nz, respectively, from the viewpoint of reducing the viewing angle dependence, the following formula: 0.5 <(Nx-N
z) / (Nx-Ny) <1.5, 0.5 <(nx-n
It is preferable that y) / (nx-ny) <1.5 is satisfied, and 0.7 <(Nx-Nz) / (Nx-Ny) <
1.3, 0.7 <(nx-nz) / (nx-ny) <
It is preferable to satisfy 1.3.

In the case of the three-kind five-layer structure, the sum of the retardation values (Re) at the wavelength of 550 nm of the first layer and the third layer is 400 to 800 nm with reference to the stretching axis direction. Preferably, the retardation value (Re) in the second layer is -660 to -260 nm, and the retardation value (Re) in the first transparent substrate is 100 to 160 nm.

The first transparent substrate of the three-kind five-layer structure is
For example, it can be obtained as follows. That is, in an extruder having a die, a norbornene resin, a styrene-maleic anhydride resin, and a resin that forms the adhesion layer are respectively stored, and these are heated and pressurized to bring them into a fluidized state, respectively, and then from the die. It is obtained by continuously extruding each of them into a laminated body and continuously inserting the laminated body into a nip portion of a nip roll to perform pressure bonding. In addition, a plurality of flow paths are provided between the storage position of each resin in the extruder and the die, these flow paths are united immediately before the die, and a laminate having a three-kind five-layer structure is extruded at one time. To be

In the first type transparent substrate having the three-kind five-layer structure, Ts <Tn, where Ts and Tn are the melting and softening temperatures of the styrene maleic anhydride resin and the norbornene resin, respectively. When a laminate of a layer made of the norbornene resin and a layer made of the styrene-maleic anhydride resin is stretched at a temperature, orientation relaxation of molecules in the styrene-maleic anhydride resin is fast, so that molecules in the layer made of the styrene-maleic anhydride resin are Almost no orientation, and the layer of styrene maleic anhydride resin has no birefringence. As a result, the first transparent substrate, which is a laminate of the norbornene resin layer and the styrene-maleic anhydride resin layer, has a retardation (Re) substantially equal to that of the norbornene resin layer. However, as the stretching temperature is lowered, the styrene-maleic anhydride resin is oriented, and the layer of the styrene-maleic anhydride resin has birefringence. Since the layer retardation (Re) of the styrene-maleic anhydride resin is negative, the positive retardation (Re) of the norbornene resin layer is
Is reduced. The rate of decrease in the retardation (Re) is greatly decreased on the short wavelength side due to the wavelength dispersion of the styrene maleic anhydride resin,
As a result, Re (450) <Re (550) <Re
The characteristic of (650) is obtained. Therefore, by controlling the stretching temperature, the Re
(Λ) / λ is constant, and it is possible to obtain the first transparent substrate having a uniform retardation property in a wavelength region of a wide band, and by appropriately adjusting the stretching ratio, The said 1st transparent substrate which shows a characteristic can be obtained.

The first transparent substrate has wavelengths of 450 nm and 5
Retardation value at 50 nm and 650 nm (R
e) is Re (450), Re (550), Re
Assuming that (650), Re (450) <Re (5
It is necessary to satisfy 50) <Re (650).
For satisfying the above formula, as a preferable combination of the polymer having a positive intrinsic birefringence value and the polymer having a negative intrinsic birefringence value, a wavelength dispersion of the intrinsic refraction value is small intrinsic birefringence value is positive. A combination of a polymer and a polymer having a large intrinsic birefringence value with a large wavelength dispersion and a negative intrinsic birefringence value, a polymer having a large intrinsic birefringence value with a large wavelength dispersion, and a polymer having a large intrinsic birefringence value Preferable examples include a combination with a polymer having a small chromatic dispersion and a negative intrinsic birefringence value.

Among such first transparent substrates, 0.2
≤ Re (450) / 450 (nm) ≤ 0.3, 0.2 ≤
Re (550) / 550 (nm) ≦ 0.3 and 0.
Those satisfying 2 ≦ Re (650) / 650 (nm) ≦ 0.3 are preferable, and 0.23 ≦ Re (450) / 450.
(Nm) ≦ 0.27, 0.23 ≦ Re (550) / 55
0 (nm) ≤ 0.27 and 0.23 ≤ Re (65
0) / 650 (nm) ≦ 0.27 is more preferable, and 0.24 ≦ Re (450) / 450 (nm)
≤0.26, 0.24≤Re (550) / 550 (n
m) ≤ 0.26 and 0.24 ≤ Re (650) / 6
A material satisfying 50 (nm) ≦ 0.26 is more preferable, and a broadband quarter-wave plate is particularly preferable.

The photoelasticity of the first transparent substrate is appropriately selected depending on the intended purpose without any restriction, but it is preferably 10 Brewster or less.
It is more preferably 5 Brewster or less. When the photoelasticity of the first transparent substrate is 10 Brewster or less, a retardation difference may partially occur in the first transparent substrate even if stress is applied to the first transparent substrate unevenly. It can be effectively suppressed.

The thickness of the first transparent substrate is not particularly limited and can be appropriately selected according to the purpose.

It is preferable that a polarizing plate is provided on the surface of the first transparent substrate opposite to the transparent conductive film. The polarizing plate is appropriately selected depending on the intended purpose without any limitation.

The second transparent substrate is not particularly limited except that it has the transparent conductive film on the surface, and can be appropriately selected according to the purpose. For example, a glass substrate is preferable.

It is preferable that the first transparent substrate and the second transparent substrate are arranged at a constant interval via a spacer. The spacer is appropriately selected depending on the intended purpose without any limitation, and examples of the method for providing the spacer include a method by photolithography and a printing method.

The touch panel of the present invention can be suitably used for liquid crystal displays of various devices such as word processors, personal computers, mobile phones, digital cameras, video cameras, ticket vending machines, and the like. It can be used particularly suitably for a display device.

(Liquid crystal display device with a touch panel) The liquid crystal display device with a touch panel of the present invention is not particularly limited except that the touch panel of the present invention is provided on the liquid crystal display, and it is a publicly known one appropriately selected according to the purpose. The configuration described above can be adopted, and for example, a lead wire for bias application is appropriately provided. The liquid crystal display is not particularly limited and may be appropriately selected depending on the intended purpose. For example, in addition to the liquid crystal layer, a back light or the like is appropriately provided.

The liquid crystal display device with a touch panel of the present invention can be suitably used as, for example, a word processor, a personal computer, a mobile phone, a digital camera, a video camera, a ticket vending machine, or the like.

[0081]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to the following examples.

Example 1 A norbornene resin (Arton, manufactured by JRS) was used as the polymer having a positive intrinsic birefringence value, and a styrene maleic anhydride resin was used as a polymer having a negative intrinsic birefringence value. (Nova Chemical Co., Ltd., Dailark D332, Tg = 131 ° C.), and the two are mixed in a mass ratio of norbornene resin: polystyrene = 77: 23 to dissolve a polymer blend in a methylene chloride solution to obtain a coating solution. Was prepared.

The viscosity of the coating solution is 9.8 Pa · s (9
8 poise), and the coating solution was cast on a glass plate using a doctor blade and dried to a thickness of 107 μm.
To form a transparent film. This transparent film is 1
A birefringent film was obtained by uniaxially stretching 13% at 50 ° C. The wavelength dispersion of the Re value of the birefringent film was measured using a retardation measuring device (KOBRA21DH manufactured by Oji Scientific Co., Ltd.). As a result, the birefringent film was Re (450) <Re (550) <Re. (650)
The Re value (Re / wavelength) value is about 0.25 in the entire visible light range, and is 1 / wide band.
It was a retardation plate showing a four-wave plate characteristic. Further, the photoelastic modulus of this birefringent film was 13 Brewster as measured by M-150 manufactured by JASCO Corporation. The birefringent film obtained as described above was used as the first transparent substrate.

On the first transparent substrate, indium tin oxide (ITO) having a thickness of 500 n was formed by a sputtering method.
Then, a transparent conductive film was formed by depositing and forming the transparent conductive film.

A transparent glass substrate is used as the second transparent substrate, and indium tin oxide (IT
O) was deposited by sputtering to a thickness of 500 nm to form a transparent conductive film. Further, dot-shaped conductive portions were formed on the transparent conductive film.

A liquid crystal display device with a touch panel shown in FIG. 1 was manufactured using the first transparent substrate and the second transparent substrate obtained as described above. That is, first, the first transparent substrate 10 having the transparent conductive film 12 formed as described above on the surface thereof,
Second transparent substrate 22 having transparent conductive film 22 formed on its surface
And the transparent conductive film 12 and the transparent conductive film 22 are arranged so as to face each other via the spacer 30.
The transparent conductive film 12 and the transparent conductive film 22 are adapted to conduct electricity when they come into contact with each other. Whether the electricity is conducted or not is determined by a detector connected to the transparent conductive film 12 and the transparent conductive film 22. It can be detected by 32. Next, the polarizing plate 14 is disposed on the side of the first transparent substrate 10 opposite to the side on which the transparent conductive film 12 is formed, and the second transparent substrate 20
The liquid crystal display 40 was arranged on the side opposite to the side on which the transparent conductive film 22 was formed, and a liquid crystal display device with a touch panel was manufactured.

In this liquid crystal display device with a touch panel, the touch panel 1 is provided on the liquid crystal display 40. The touch panel 1 includes a second transparent substrate 20, a transparent conductive film 22, and a dot-shaped conductive portion 32 in this order from the liquid crystal display 40 side, and further includes a spacer 30 and a first transparent substrate 10 and a transparent conductive film. 12 and a polarizing plate 14 are provided in this order.

Therefore, in this liquid crystal display device with a touch panel, when a part of the surface of the touch panel 1 is pressed, the transparent conductive film 12 and the transparent conductive film 22 come into contact with each other at the pressed position. At this time, the transparent conductive film 1
A pair of electrodes and a lead wire (not shown) are connected to both ends of the transparent conductive film 22, and a pair of electrodes and a lead wire (not shown) connected to both ends of the transparent conductive film 12 in the transparent conductive film 22. A pair of electrodes and lead wires (not shown) are also connected to both ends in the orthogonal direction. A bias is applied to one of the pair of lead wires, and the other is connected to GND. As a result, the transparent conductive film 12
When the transparent conductive film 22 and the transparent conductive film 22 contact each other, the current value flowing between the pair of electrodes changes, and the detector 32 detects the change and the contact point position is specified.

First transparent substrate 10 in touch panel 1
Is Re (450) <Re (550) <Re (650)
Since it is a wideband quarter-wave plate having the characteristic, even if external light having an arbitrary wavelength is incident on the touch panel 1, the external light passes through the polarizing plate 14 to become linearly polarized light, and then the wideband 1/4 wavelength plate. Circularly polarized light is transmitted through the first transparent substrate 10 which is a four-wave plate, is reflected by the transparent conductive film 12, is transmitted through the first transparent substrate 10 to be linearly polarized light, is transmitted through the polarizing plate 14, and is linearly polarized light. Is emitted to the outside again. Therefore, the diffused reflection by the transparent conductive film 12 with respect to the incident light of any wavelength in the wide band is small, and thus the touch panel 1 has excellent visibility.

(Comparative Example 1) In Example 1, the norbornene resin was not used and the viscosity of the coating solution was 8.9 Pa · s.
And a birefringent film was produced in the same manner as in Example 1 except that the transparent film was uniaxially stretched at 140 ° C. by 5%, and the wavelength dispersion of the retardation (Re) value was measured in the same manner as in Example 1. The birefringent film has (Re / wavelength)
The value was out of 0.2 to 0.3. A liquid crystal display with a touch panel was manufactured in the same manner as in Example 1 except that this birefringent film was used as the first transparent substrate 10. In this liquid crystal display with a touch panel, incident light is diffusely reflected by the transparent conductive film 12, and the touch panel 1 has poor visibility.

(Comparative Example 2) In Example 1, the styrene-maleic anhydride resin was not used, and the viscosity of the coating solution was 1
3.2 Pa · s, transparent film 25% at 155 ° C
A birefringent film was produced in the same manner as in Example 1 except that it was uniaxially stretched, and the retardation (R
As a result of measuring the wavelength dispersion of the value e), the (Re / wavelength) value of the birefringent film was out of the range of 0.2 to 0.3. A liquid crystal display with a touch panel was manufactured in the same manner as in Example 1 except that this birefringent film was used as the first transparent substrate 10. In this liquid crystal display with a touch panel, incident light is diffusely reflected by the transparent conductive film 12, and the touch panel 1 has poor visibility.

(Example 2) In Example 1, a norbornene resin and a styrene-maleic anhydride resin were coextruded using an extruder without using a polymer blend to obtain a laminate, and then, in a 132 ° C. atmosphere. 32%, and a birefringent film having a two-layer structure in which a layer 16 made of norbornene resin and a layer 18 made of styrene-maleic anhydride resin were laminated was obtained, as shown in FIG. This birefringent film was produced by the same method as in Example 1 with Re (450)
It was a broadband quarter-wave plate having the characteristics of <Re (550) <Re (650). In the liquid crystal display with a touch panel of Example 2 using this birefringent film as the first transparent substrate 10, the incident light is transparent to the conductive film 1.
2 did not cause irregular reflection, and the touch panel 1 had excellent visibility.

(Example 3) Norbornene resin (Zeonor 1420; manufactured by Nippon Zeon Co .; Tg = 136 ° C.) as a polymer having a positive intrinsic birefringence value, and styrene maleic anhydride resin as a polymer having a negative intrinsic birefringence value. (Nova Chemical Co., Dailark D332, Tg = 131 ° C.),
A coextruded film of three-kind five-layer structure as shown in FIG. 3, using a hot melt resin (Mitsui Chemicals, Inc., Admer, type SE800; Bigat softening point measured according to ASTM D1525 of 59 ° C.) as the adhesion layer. The first transparent substrate 10 made of (birefringent film) was produced using the production apparatus shown in FIG.

In the manufacturing apparatus of FIG. 4, three extruders 62, 64 and 65 are integrally combined with an extrusion die 66. The extrusion flow paths from the respective extruders 52, 54 and 55 for extruding the norbornene resin, the styrene maleic anhydride resin and the hot melt resin for forming the adhesion layer are merged into one inside the extrusion die 56, From the extrusion die 56, a laminated film 58 having a five-layer structure made of three kinds of resins,
That is, as shown in FIG. 4, the layer 1 made of norbornene resin is used.
6, adhesion layer 19, styrene maleic anhydride resin layer 18, adhesion layer 19, and norbornene resin layer 1
A laminated film 58 having a three-kind five-layer structure formed by laminating in the order of 6 is extrusion formed.

Next, the laminated film 58 formed by extrusion.
Moves sequentially following the rotation of the rolls 60, 62 and 64. Since the rolls 60, 62 and 64 rotate at different peripheral speeds, the laminated film 58 is cooled and adjusted to a desired thickness while moving.
Then, the laminated film 58 is a stretching roll (heat roll).
The nip portion of 66 and 68 stretches the film to a stretching ratio of 32% to obtain a stretched film 58a exhibiting birefringence. The thickness of each layer in the stretched film 58a is as follows: the layer 16a made of norbornene resin, the adhesion layer 19, the layer 18a made of styrene-maleic anhydride resin, the adhesion layer 1
9, 44 μm in order of the layer 16a made of norbornene resin
/1.8 μm / 63 μm / 1.8 μm / 42 μm. A heater (not shown) is built in the cores of the stretching rolls (heat rolls) 66 and 68, and the temperature of each heater can be controlled by a controller 70. Stretching temperature is 132 ℃
Is controlled so that

Then, the optical measuring instrument 72 measures the retardation (Re) of the stretched film 58a immediately after stretching. The detection data of the measurement wavelength and the retardation is input from the optical measuring device 72 to the controller 70. Ideal standard wavelength-retardation (Re) correlation standard data is input to the controller 70 in advance, and a program is input to increase or decrease the stretching temperature based on the deviation of the input data from the standard data. There is. Thus, by measuring the retardation of the stretched film at the wavelength and controlling the stretching temperature based on this data, the stretched film 58a functioning as a broadband quarter-wave plate with uniform wavelength dispersion can be obtained. Here, 5
The thickness ratio of each layer also affects the wavelength dispersion of the retardation (Re), and therefore the stretched film 58 on the line
Based on the measured value of the retardation (Re) of a, the extrusion amounts of the three resins from the extruders 52, 54 and 55 per unit time can also be controlled. afterwards,
The first transparent substrate 10 was obtained by cutting the stretched film 58a into a desired size with a cutting machine (not shown) arranged downstream.

The wavelength dependency of the retardation (Re) of the obtained first transparent substrate 10 was KO manufactured by Oji Scientific Co., Ltd.
When measured using BRA 21DH, as shown in FIG. 4, the first transparent substrate 10 (32% stretched film) was
It had a broadband ¼ wavelength plate characteristic in which the retardation (Re) was ¼ of the wavelength over the entire visible light range.
The photoelasticity was 3 Brewster as measured by M-150 manufactured by JASCO Corporation.

In the liquid crystal display with a touch panel of Example 3 used as the first transparent substrate 10, incident light was not diffusely reflected by the transparent conductive film 12, and the touch panel 1 had excellent visibility.

Comparative Example 3 A single layer film having a thickness of 103 μm was obtained by using a norbornene resin (Zeonor 1420, manufactured by Nippon Zeon Co., Ltd .; Tg = 136 ° C.). The obtained monolayer film was stretched 28% at 130 ° C. to obtain a stretched film. When the wavelength dependence of the retardation (Re) of this stretched film was measured, it did not show the characteristics of a broadband quarter-wave plate as shown in FIG. Example 1 except that this stretched film was used as the first transparent substrate 10.
A liquid crystal display with a touch panel was manufactured in the same manner as in. In this liquid crystal display with a touch panel, incident light is diffusely reflected by the transparent conductive film 12, and the touch panel 1 has poor visibility.

Comparative Example 4 Styrene Maleic Anhydride Resin (Nova Chemical Co., Dailark D332; Tg = 13)
(1 ° C.) was used to obtain a monolayer film having a thickness of 101 μm. The obtained monolayer film was stretched at 100 ° C. by 18% to obtain a stretched film. When the wavelength dependence of the retardation (Re) of this stretched film was measured, it did not show the characteristics of a broadband quarter-wave plate as shown in FIG. A liquid crystal display with a touch panel was manufactured in the same manner as in Example 1 except that this stretched film was used as the first transparent substrate 10. In this liquid crystal display with a touch panel, incident light is diffusely reflected by the transparent conductive film 12, and the touch panel 1 has poor visibility.

[0101]

According to the present invention, a touch panel which solves the above problems in the related art, is easy to manufacture, and effectively suppresses diffused reflection of incident light in a wide wavelength range, and a touch panel having the wide wavelength range is provided. It is possible to provide a liquid crystal display device with a touch panel that effectively suppresses irregular reflection of incident light and has excellent visibility.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional explanatory view for explaining a liquid crystal display device with a touch panel including the touch panel of the present invention.

FIG. 2 is a schematic cross-sectional explanatory view showing an example of a first transparent substrate in the liquid crystal display device with a touch panel shown in FIG.

3 is a schematic cross-sectional explanatory view showing another example of the first transparent substrate in the liquid crystal display device with a touch panel shown in FIG.

FIG. 4 is a schematic view for explaining an example of manufacturing a first transparent substrate in the liquid crystal display device with a touch panel shown in FIG.

FIG. 5 is a graph showing wavelength dispersion of retardation of the first transparent substrate in Example 3.

FIG. 6 is a graph showing the wavelength dispersion of retardation of the first transparent substrate in Comparative Examples 3 and 4.

[Explanation of symbols] 1 touch panel 10 First transparent substrate 12 Transparent conductive film 14 Polarizer 16 Layers of polymers having a positive intrinsic birefringence 16a layer of norbornene resin 18 Layer made of polymer having negative intrinsic birefringence value 18a Layer made of styrene maleic anhydride resin 19 Adhesion layer 20 Second transparent substrate 22 Transparent conductive film 30 spacer 32 dot conductive parts 34 detector 40 LCD display 50 Manufacturing equipment 52 Extruder 53 extruder 54 extruder 56 Extrusion die 58 laminated film 58a stretched film 60 rolls 62 rolls 64 rolls 66 Drawing roll 68 Drawing roll 70 controller 72 Optical measuring instrument

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01H 13/02 H01H 13/02 B 13/70 13/70 C F term (reference) 2H089 HA18 QA12 QA16 SA02 SA17 TA02 5B087 AA09 CC02 CC14 CC37 5C094 AA11 BA43 DA06 EA02 EB02 ED14 JA11 5G006 AA01 BB07 CD03 CD04 FB01 FB03 FB14 FB17 FB24 FB30 FB31 FB39 JA01 JB05 JC01 JD01 JF27 5G435 AEE02 BB12 A0802BB12

Claims (11)

[Claims] 1. A first transparent substrate and a second transparent substrate having a transparent conductive film on a surface thereof are arranged such that the transparent conductive films face each other with a constant space therebetween, and the first transparent substrate comprises It contains a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value, and the retardation values (Re) at wavelengths of 450 nm, 550 nm and 650 nm are Re (450) and
If Re (550) and Re (650), then Re (45
0) <Re (550) <Re (650). 2. The touch panel according to claim 1, further comprising a polarizing plate on a surface of the first transparent substrate opposite to the transparent conductive film. 3. The first transparent substrate is 0.2 ≦ Re (45
0) / 450 (nm) ≦ 0.3, 0.2 ≦ Re (55
0) / 550 (nm) ≦ 0.3 and 0.2 ≦ Re
The touch panel according to claim 1, wherein (650) / 650 (nm) ≦ 0.3 is satisfied. 4. The touch panel according to claim 1, wherein the first transparent substrate is formed of a polymer blend of a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value. . 5. The first transparent substrate according to claim 1, wherein a layer made of a polymer having a positive intrinsic birefringence value and a layer made of a polymer having a negative intrinsic birefringence value are laminated. The touch panel described. 6. The touch panel according to claim 5, wherein a slow axis of a layer made of a polymer having a positive intrinsic birefringence value and a slow axis of a layer made of a polymer having a negative intrinsic birefringence value are orthogonal to each other. 7. The touch panel according to claim 1, wherein the polymer having a positive intrinsic birefringence value is a cycloolefin resin. 8. The touch panel according to claim 1, wherein the polymer having a negative intrinsic birefringence value is a styrene resin. 9. The first transparent substrate comprises a first layer formed of norbornene resin having a positive intrinsic birefringence value, and a second layer formed of styrene maleic anhydride resin having a negative intrinsic birefringence value. And a third layer formed of a norbornene resin having a positive intrinsic birefringence value, which are laminated in this order so that the orientation directions thereof coincide with each other, and between the first layer and the second layer. And a hot melt resin having a softening point lower than the glass transition point (Tg) of the norbornene resin and the glass transition point (Tg) of the styrene maleic anhydride resin between the second layer and the third layer. The touch panel according to claim 5, further comprising an adhesive layer formed in. 10. The touch panel according to claim 1, wherein the second transparent substrate is a glass substrate. 11. A liquid crystal display device with a touch panel, comprising the touch panel according to claim 1 on a liquid crystal display.