JP2002316378A - Transparent conductive laminated body and touch panel using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive laminated body improved in its transparency and scratch resistance and flex resistance of the conductive thin film and improved in a pen input durability as a touch panel use in the transparent conductive thin film using a film substrate. SOLUTION: The transparent conductive laminated body is provided wherein a transparent first dielectric thin film, a transparent second dielectric thin film and a transparent conductive thin film are laminated in this order on one side surface of a transparent film substrate of 2-120 μm in thickness, and a transparent substrate is stuck to the other surface of the film substrate via a transparent pressure sensitive adhesive layer. When a refractivity of light of the film substrate is n1 , a refractivity of light of the first dielectric thin film is n1 , a refractivity of light of the second dielectric thin film is n3 and a refractivity of light of the electrical conductive thin film is n4 , the transparent conductive laminated body satisfies a relation of n3 <n2 <=n1 <n4 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent conductive laminate having a film substrate and a touch panel using the same.

[0002]

2. Description of the Related Art In general, thin films that are transparent in the visible light region and have electrical conductivity include transparent electrodes in new display systems such as liquid crystal displays and electroluminescence displays, touch panels, etc., as well as for preventing static electricity in transparent articles and preventing electromagnetic waves. It is used for blocking.

Conventionally, as such a transparent conductive thin film,
A so-called conductive glass in which an indium oxide thin film is formed on glass is well known, but is inferior in flexibility and workability because the base material is glass, and may not be used depending on the application.

[0004] For this reason, in recent years, in addition to flexibility and workability, it has excellent advantages such as excellent impact resistance and light weight. Therefore, a transparent conductive film made of various plastic films such as a polyethylene terephthalate film is used as a base material. A conductive thin film is used.

[0005]

However, the conventional transparent conductive thin film using such a film substrate has a problem that it is inferior in transparency due to a large light reflectance on the surface of the thin film. There is a problem that the scratch resistance and bending resistance of the conductive thin film are inferior, and the film is scratched during use, increasing the electric resistance and causing disconnection.

In a conductive thin film particularly for a touch panel, a pair of thin films opposed to each other via a spacer come into strong contact with each other at a pressing point from one of the panel plates. It is desired to have good durability characteristics, that is, hitting characteristics, but the above-mentioned conventional transparent conductive thin film is inferior in such characteristics, and there is a problem that the life of the touch panel is shortened accordingly.

[0007] In order to solve the above-mentioned conventional problems, the present invention relates to a transparent conductive thin film using a film substrate such as a polyethylene terephthalate film, which has improved transparency, scratch resistance and bending resistance of the conductive thin film. It is intended to improve the pen input durability for touch panels as well as to improve it.

[0008]

In order to achieve the above object, the transparent conductive laminate of the present invention has a thickness of 2 to 120 μm.
m, a transparent first dielectric thin film, a transparent second dielectric thin film, and a transparent conductive thin film are laminated in this order on one surface of a transparent film substrate of A transparent conductive laminate obtained by laminating a transparent substrate on a surface of the first dielectric thin film with a transparent adhesive layer interposed therebetween, wherein the film substrate has a refractive index of light n ₁ , and a light refractive index of the first dielectric thin film. The refractive index is n ₂ ,
When the refractive index of light of the second dielectric thin film is n ₃ and the refractive index of light of the conductive thin film is n ₄ , n ₃ <n ₂ ≦ n ₁ <n
The relationship of ₄ is satisfied.

In the transparent conductive laminate of the present invention, it is preferable that the first dielectric thin film is an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance.

[0010] In the transparent conductive laminate of the present invention, the second dielectric thin film is preferably an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance.

Further, the touch panel of the present invention is a touch panel in which a pair of panel plates having a conductive thin film are arranged to face each other via a spacer so that the conductive thin films face each other. At least one is made of the transparent conductive laminate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The film substrate used in the present invention is not particularly limited, and an appropriate one can be used.
For example, polyester resins and acetate resins, polyethersulfone resins and polycarbonate resins, polyamide resins and polyimide resins, polyolefin resins and acrylic resins, polyvinyl chloride resins and polystyrene resins, polyolefin resins and A polyvinyl alcohol-based resin, a polyarylate-based resin, a polyphenylene sulfide-based resin, a polyvinylidene chloride-based resin, a (meth) acryl-based resin, or the like can be used. Among them, particularly preferred are polyester-based resins, polycarbonate-based resins, and polyolefin-based resins.

The thickness of these film substrates is 2 to 120
μm, particularly preferably 6 to 10 μm.
It is preferably in the range of 0 μm. When the thickness is less than 2 μm, the mechanical strength of the film base material is insufficient, and it is difficult to continuously form a dielectric thin film, a conductive thin film, and a pressure-sensitive adhesive layer by using the base material as a roll. On the other hand, if it exceeds 120 μm, it becomes impossible to improve the abrasion resistance of the conductive thin film based on the cushioning effect of the pressure-sensitive adhesive layer described later and the pen input durability for touch panels.

This film substrate is subjected to an etching treatment or undercoat treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation or the like on the surface in advance. You may make it improve the adhesiveness with respect to a base material. Before providing the dielectric thin film, dust removal and cleaning may be performed by solvent cleaning, ultrasonic cleaning, or the like, as necessary.

In the present invention, transparent first and second dielectric thin films are formed on one surface of such a film substrate. The refractive indices n ₂ and n ₃ of the light of the dielectric thin film need to be smaller than the refractive index n ₄ of the light of the conductive thin film provided on the dielectric thin film. since the refractive index n ₄ is about 2, the refractive index n _2, n ₃ of the optical dielectric thin film, it is preferable is usually about 1.3 to 1.9. By the formation of the dielectric thin film, the scratch resistance and the bending resistance of the transparent and conductive thin films are largely improved, and good results are also obtained in the improvement of the hitting characteristic for touch panels.

As a material of such a dielectric thin film, for example, NaF (1.3), Na ₃ A1F ₆ (1.35),
LiF (1.36), MgF ₂ (1.38), CaF
₂ (1.4), BaF ₂ (1.3), SiO ₂ (1.4
6), LaF ₃ (1.55), CeF ₃ (1.63), A
Numbers in inorganic [above the material (), such as 1 ₂ O ₃ (1.63) is the refractive index of the light. ] And the refractive index of light is 1.4.
There are organic substances such as acrylic resins, urethane resins, siloxane-based polymers, etc. of about 1.6 or a mixture of the above-mentioned inorganic substances and the above-mentioned organic substances, and among these, the refractive indices n ₂ and n _{3 of} light satisfy the above relation. Is selected and used. In this,
Organic substances, MgF ₂ , SiO ₂ , Al ₂ O _{3 and the} like are particularly preferably used.

The total thickness of the dielectric thin film is not particularly limited. The thickness of the first dielectric thin film is preferably 10 nm or more, and more preferably 10 to 3000 nm. If it is less than 10 nm, it is difficult to form a continuous film, and it is 3000
If it is more than nm, a problem occurs in the bending resistance. The thickness of the second dielectric thin film is preferably 10 nm or more, preferably 10 to 300 nm, particularly preferably 20 to 12 nm.
The range is preferably 0 nm. If it is less than 10 nm, it is difficult to form a continuous film, and the improvement in transparency and scratch resistance cannot be expected much. If the thickness is too large, improvement in transparency cannot be expected, and cracks may occur, which is not preferable.

As a method of forming a dielectric thin film, for example,
There are a vacuum deposition method, a sputtering method, an ion plating method, a coating method, and the like, and an appropriate method can be adopted according to the type of the above-described material and the required film thickness.

In the present invention, after forming a transparent dielectric thin film as described above, a transparent conductive thin film is further formed on this thin film. As a method for forming the conductive thin film, the same technique as that for the dielectric thin film can be adopted. The thin film material to be used is not particularly limited. For example, indium oxide containing tin oxide, tin oxide containing antimony, and the like are preferably used.

As described above, the refractive index n ₄ of the conductive thin film made of these materials is usually about 2, and the refractive index n ₁ of the light of the film substrate is usually 1.4 to 1.7. For this reason, the refractive index is larger than n ₁ . Therefore, the relationship between these and the refractive indices n ₂ and n ₃ of light of the dielectric thin film is n ₃
<N ₂ ≦ n ₁ <n ₄ .

The thickness of the conductive thin film is preferably at least 10 nm.
^It is difficult to form a continuous film having good conductivity of ³ (Ω / □) or less. Further, if the thickness is too large, the transparency is lowered.
The thickness is preferably about 00 nm.

On the other surface of the film substrate on which such a transparent dielectric thin film and a transparent conductive thin film are sequentially formed, a transparent substrate is bonded via a transparent adhesive layer. For this bonding, the above-mentioned pressure-sensitive adhesive layer may be provided on the transparent substrate, and the above-mentioned film substrate may be bonded thereto, or conversely, the above-mentioned pressure-sensitive adhesive layer may be formed on the film substrate. May be provided, and a transparent substrate may be attached to this. The latter method is more advantageous in terms of productivity because the pressure-sensitive adhesive layer can be formed continuously by rolling the film substrate.

The pressure-sensitive adhesive layer can be used without any particular limitation as long as it has transparency. For example, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives and the like are used. The pressure-sensitive adhesive layer has a function of improving the abrasion resistance of the conductive thin film provided on one surface of the film substrate and the hitting characteristic for a touch panel by the cushion effect after bonding the transparent substrate. From the viewpoint of better exhibiting this function, the elastic modulus of the pressure-sensitive adhesive layer is set to 1 × 10 ⁵ to 1 × 1.
0. ⁷ dyn / cm ² , thickness of 1 μm or more, usually 5 to 5 dyn / cm ²
It is desirable to set it in the range of 100 μm.

When the elastic modulus is less than 1 × 10 ⁵ dyn / cm ² , the pressure-sensitive adhesive layer becomes inelastic, so that the pressure-sensitive adhesive layer is easily deformed by pressurization and causes irregularities in the film base material and thus the conductive thin film, In addition, the pressure-sensitive adhesive is likely to protrude from the cut surface to be processed, and the effect of improving the scratch resistance of the conductive thin film and the hitting characteristics for touch panels is reduced.
On the other hand, when the elastic modulus exceeds 1 × 10 ⁷ dyn / cm ² ,
Since the pressure-sensitive adhesive layer becomes hard and its cushion effect cannot be expected, the scratch resistance of the conductive thin film and the hitting characteristics for touch panels cannot be improved.

When the thickness of the pressure-sensitive adhesive layer is less than 1 μm, the cushioning effect cannot be expected, so that the scratch resistance of the conductive thin film and the improvement of the hitting characteristic for touch panels cannot be expected. On the other hand, if the thickness is too large, transparency is impaired, and it is difficult to obtain good results in terms of the formation of the pressure-sensitive adhesive layer, the workability of bonding the transparent substrate, and the cost.

The transparent substrate bonded through the pressure-sensitive adhesive layer imparts good mechanical strength to the film substrate, and particularly contributes to the prevention of curling and the like. When flexibility is required even after the combination, a plastic film of about 6 to 300 μm is usually used, and when flexibility is not particularly required, a glass plate of about 0.05 to 10 mm is usually used. Or a plastic in the form of a film or a plate. Examples of the plastic material include the same materials as those of the above-mentioned film substrate.

If necessary, an anti-glare treatment layer or an anti-reflection treatment layer for improving visibility may be provided on the outer surface of the transparent substrate (the surface opposite to the pressure-sensitive adhesive layer). A hard coat treatment layer for protecting the outer surface may be provided. As the latter hard coat treatment layer, for example, a cured film made of a curable resin such as a melanin resin, a urethane resin, an alkyd resin, an acrylic resin, and a silicon resin is preferably used.

FIG. 1 shows an example of the transparent conductive laminate of the present invention. A transparent film substrate 1 has a transparent first dielectric thin film 2 and a second dielectric thin film on one surface thereof. 3 and a transparent conductive thin film 4 are further laminated thereon, and a transparent substrate 6 is bonded to the other surface via a transparent adhesive layer 5. FIG. 2 shows another example of the transparent conductive laminate of the present invention, in which a hard coat treatment layer 7 is provided on the outer surface of the transparent substrate 6. It is exactly the same as FIG.

FIG. 3 shows an example of a touch panel using the transparent conductive laminate of the present invention.
In a touch panel in which a pair of panel boards P1 and P2 having a pair of conductive boards 4a and 4b are disposed so as to face each other via a spacer 8 so that conductive thin films 4a and 4b formed perpendicular to each other face each other, In this case, the transparent conductive laminate shown in FIG. 2 is used.

In the touch panel, when the input pen 10 presses and presses against the elastic force of the spacer 8 from the panel plate P1, the conductive thin films 4a and 4b come into contact with each other.
When the electric circuit is turned on and the pressing is released, the circuit returns to the original off state and functions as a transparent switch assembly. At that time, since the panel plate P1 is made of the above-described transparent conductive laminate, the conductive thin film has excellent scratch resistance, hitting characteristics, bending resistance, and the like, and can stably maintain the above function for a long period of time.

In FIG. 3, the panel plate P1 may be the transparent conductive laminate shown in FIG. The panel plate P2 is formed by providing a conductive thin film 4b on a transparent substrate 9 made of a plastic film, a glass plate, or the like. The transparent conductive laminate shown in FIG. 1 or FIG. A body may be used.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. In the following, “parts” means “parts by mass”.

Example 1 A melamine resin: alkyd resin: organic was applied to one surface of a film substrate (light refractive index n ₁ = 1.66) made of a polyethylene terephthalate film (PET film) having a thickness of 25 μm. A thermosetting resin having a ratio of 2: 2: 1 of silane condensate (light refractive index n
₂ = 1.54) to a thickness of 180 nm and then SiO ₂
(Refractive index of light n ₃ = 1.46) is vacuum-deposited at a degree of vacuum of (1-2) × 10 ⁻⁴ Torr by an electron beam heating method to form a transparent dielectric thin film (SiO 2) having a thickness of 40 nm. _Two
A thin film).

Next, on the SiO ₂ thin film, 4 × 10 ³ To composed of 80% of argon gas and 20% of oxygen gas.
In a rr atmosphere, a composite oxide of indium oxide and tin oxide (refractive index of light n ₃ = 2.10 nm) having a thickness of 20 nm was formed by a reactive sputtering method using an indium-tin alloy.
00) to form a transparent conductive thin film (ITO thin film).

Next, on the other surface of the PET film, an acrylic transparent pressure-sensitive adhesive layer (elastic coefficient adjusted to 1 × 10 ⁶ dyn / cm ² ) (mass of butyl acrylate, acrylic acid and vinyl acetate) 100 parts of an acrylic copolymer having a ratio of 100: 2: 5 and one part of an isocyanate-based cross-linking agent) is formed to a thickness of about 20 μm, and a PET film having a thickness of 125 μm is formed thereon. The resulting transparent base material was laminated to produce a transparent conductive laminated film having the structure shown in FIG.

The transparent conductive laminated film was used as one panel plate and the other panel plate was formed on a glass plate with a thickness of 3 mm.
A thin film having a thickness of 0 nm was formed in the same manner as above, and the two panel plates were arranged to face each other via a spacer having a thickness of 100 μm so that the ITO thin films faced each other. Produced. In addition, each ITO thin film of both panel boards was previously formed so as to be orthogonal to each other, prior to the above-described facing arrangement.

(Example 2) An acrylic / urethane resin [Unidick 17-806 manufactured by Dainippon Ink and Chemicals, Inc.] 1 was applied to one surface of a PET film having a thickness of 125 μm.
A toluene solution prepared by adding 5 parts of hydroxycyclohexyl phenyl ketone [Irgacure 184 manufactured by Ciba Geigy Co., Ltd.] as a photopolymerization initiator to 00 parts and diluting the mixture to a concentration of 50% by mass was applied thereto, and then heated at 100 ° C. for 3 minutes. Immediately after drying, an ozone-type high-pressure mercury lamp (80 W / cm, 1
UV irradiation with 2 lamps, 5μm thick
Was formed.

PET having the hard coat layer formed thereon
2 in the same manner as in Example 1 except that the film was used as a transparent substrate and the transparent substrate was bonded via an adhesive layer from the side opposite to the hard coat treatment layer.
A transparent conductive laminated film having the structure shown in was prepared. Further, a touch panel having the structure shown in FIG. 3 was produced in the same manner as in Example 1 using this laminated film.

(Example 3) A thermosetting resin (light refractive index n ₂ = 1.54) having a ratio of 2: 2: 1 of melamine resin: alkyd resin: organosilane condensate was formed to a thickness of 2 μm. A transparent conductive laminated film and a touch panel using the same were prepared in the same manner as in Example 1 except for the above.

Example 4 A thermosetting resin (refractive index n = 1.54) of melamine resin: alkyd resin: organosilane condensate in a ratio of 2: 2: 1 was applied to TiO ₂ (light refraction). The refractive index n ₂ =
A transparent conductive laminated film and a touch panel using the same were produced in the same manner as in Example 1 except that a dielectric thin film having a thickness of 2 μm was formed by adjusting the compounding ratio so as to be 1.66.

Comparative Example 1 A transparent conductive laminated film and the same were used in the same manner as in Example 1 except that the dielectric thin film was changed to Al ₂ O ₃ (refractive index of light n ₃ = 1.63). A touch panel was manufactured.

Comparative Example 2 A transparent conductive laminated film and a transparent conductive laminated film were used in the same manner as in Example 1 except that a 175 μm-thick polyester film was used as a film substrate, and an adhesive and a transparent substrate were laminated. The touch panel was made.

Comparative Example 3 A transparent conductive laminated film was prepared in the same manner as in Example 3 except that a 175 μm-thick polyester film was used as a film substrate, and an adhesive and a transparent substrate were bonded. Using this film, a touch panel was produced in the same manner as in Example 1.

For each of the transparent conductive laminated films of Examples 1 to 4 and Comparative Examples 1 to 3, the film resistance, light transmittance, and abrasion resistance of the conductive thin film were measured by the following methods. In addition, the hitting point characteristics and the bending resistance of the touch panels of Examples 1 to 4 and Comparative Examples 1 to 3 were measured by the following methods. Table 1 shows the results.

<Film Resistance> The surface electric resistance (Ω / □) of the film was measured by a two-terminal method.

<Light Transmittance> The visible light transmittance at a light wavelength of 550 nm was measured using a spectrophotometer UV-240 manufactured by Shimadzu Corporation.

<Scratch Resistance of Conductive Thin Film> Using a Haydon surface property measuring device TYPE-HEIDON14 manufactured by Shinto Kagaku Co., Ltd., scratches: gauze (Japanese Pharmacopoeia type I), load: 100 g / cm ² , scratch Speed: 30cm / min,
The number of abrasions: 100 times (50 reciprocations), the film resistance (Rs) was measured after rubbing the conductive thin film surface, and the rate of change (Rs / R) with respect to the initial film resistance (Ro) was measured.
For o), the scratch resistance was evaluated.

<Dotting Characteristics> From the side of the panel plate made of a transparent conductive laminated film, a rod (key tip 7R) made of urethane rubber having a hardness of 40 degrees was used to apply a load of 100 g at a load of 100 g.
Film resistance (Rd)
Was measured, and the rate of change (Rd / Ro) with respect to the initial film resistance (Ro) was determined to evaluate the hitting point characteristics. In addition,
The measurement of the film resistance is performed on the contact resistance of the conductive thin films arranged opposite to each other at the time of hitting, and is expressed by an average value.

<Bending resistance> Using a Gardner-type mandrel bending tester manufactured by Taisuke Kiki Co., Ltd., the diameter was 7.93 m.
m. The sample prepared on the rod is bent 180 ° with the conductive surface outside for about 1 second. This was repeated 10 times, the film resistance (Rd) was measured, and the rate of change (Rd / Ro) with respect to the initial film resistance (Ro) was determined to evaluate the bending resistance.

[0050]

[Table 1]

As is clear from Table 1, Examples 1 to 4 of the present invention are almost superior to Comparative Examples 1 to 3 in light transmittance, scratch resistance, hitting point characteristics and bending resistance. You can see that.

[0052]

As described above, according to the present invention, the scratch resistance of the conductive thin film and the hitting characteristics as a touch panel are improved based on the hard effect of the dielectric thin film and the cushion effect of the pressure-sensitive adhesive layer, and A transparent conductive laminate having significantly improved transparency can be provided by an antireflection effect based on a combination of a dielectric thin film and a conductive thin film, and a touch panel using the same can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a transparent conductive laminate of the present invention.

FIG. 2 is a cross-sectional view of the transparent conductive laminate of the present invention.

FIG. 3 is a cross-sectional view of a touch panel using the transparent conductive laminate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film base material 2 1st dielectric thin film 3 2nd dielectric thin film 4 Conductive thin film 5 Adhesive layer 6 Transparent substrate 7 Hard coat processing layer 8 Spacer 9 Transparent substrate 10 Input pen

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01H 13/70 H01H 13/70 E (72) Inventor Takehiko Ando 1-1-1, Shimohozumi, Ibaraki-shi, Osaka No.2 Nitto Denko Corporation F-term (reference) 4F100 AA00B AA00C AA20C AA33E AH00B AH00C AK25D AK35B AK36B AK42A AL05B AR00A AR00D AR00E BA05 BA07 BA10D BA10E BA26 CA02D EH66 J41 JD08 JG01 J01 J02 J01 JN18A JN18B JN18C JN18E 5B087 AA02 BC03 CC02 CC14 CC37 DJ03 5G006 AA01 BB07 FB14 JA01 JB06 JC01 JD01 JF02 5G046 AA07 AB02 AC35 AD02 5G307 FA02 FB01 FC02 FC08 FC09 FC10

Claims (4)

[Claims] 1. A transparent first dielectric thin film, a transparent second dielectric thin film, and a transparent conductive thin film are formed on one surface of a transparent film substrate having a thickness of 2 to 120 μm in this order. A transparent conductive laminate obtained by laminating a transparent substrate on the other surface of the film substrate via a transparent pressure-sensitive adhesive layer, wherein the film substrate has a light refractive index of n ₁ , When the refractive index of light of the first dielectric thin film is n ₂ , the refractive index of light of the second dielectric thin film is n ₃ , and the refractive index of light of the conductive thin film is n ₄ , n ₃ A transparent conductive laminate characterized by satisfying a relationship of <n ₂ ≦ n ₁ <n ₄ . 2. The transparent conductive laminate according to claim 1, wherein the first dielectric thin film is an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance. 3. The transparent conductive laminate according to claim 1, wherein the second dielectric thin film is an organic substance, an inorganic substance, or a mixture of an organic substance and an inorganic substance. 4. A pair of panel plates having a conductive thin film,
A touch panel in which the conductive thin films are opposed to each other via a spacer so as to face each other, and at least one of the panel plates is formed of the transparent conductive laminate according to claim 1. A touch panel, characterized in that: