KR20130126097A - Touch screen panel comprising noise shield using conductive polymer - Google Patents

Abstract

The present invention relates to an input device with a touch screen including a noise protection film unit conductive polymer, more specifically, having excellent noise protection effect by using the conductive polymer using a new dopant as the noise protection film.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch screen input device having a noise prevention film using a conductive polymer,

The present invention relates to a touch screen input device having a noise prevention film using a conductive polymer, and more particularly, to a touch screen input device having a noise prevention effect by using a conductive polymer using a novel dopant as a noise prevention film.

The touch screen is a tool installed on a display surface of an image display apparatus such as an electronic organizer, a liquid crystal display apparatus, a flat panel display apparatus such as a PDP or an El, and a CRT or the like, and allows a user to select desired information while viewing the image display apparatus.

Such a touch screen is not limited to the signal amplification problem, the difference in resolution, the difficulty of the design and fabrication technology, and the complexity of each individual touch screen in consideration of the optical characteristics, electrical characteristics, mechanical characteristics, environmental characteristics, input characteristics, durability, And in particular, resistance film type and capacitance type are widely used in electronic notebooks, PDAs, portable PCs, mobile phones and the like.

Among these touch screens, in particular, liquid crystal displays of a capacitive coupling type all become noise, and therefore, a technique of providing a transparent conductive film as a shield on the bottom surface (liquid crystal display side) of the touch screen has been known.

However, a transparent conductive film such as ITO has to be formed in multiple layers in order to sufficiently reduce the noise, and as a result, the sensitivity of the touch decreases.

Therefore, it was necessary to develop a noise prevention film using a conductive film that can replace the existing ITO.

A possible example is a film using a conductive polymer. The doping process is necessary for the conducting polymer to have conductivity. They are usually prepared in the form of a powder or a film and then chemically doped or mixed with a conductive powder and a dopant and dissolved in an organic solvent so as to have conductivity.

Of the various conductive polymers, poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate) (PEDOT / PSS) is stable in air and has a higher room temperature electrical conductivity than other polymers and has been applied in various fields.

In particular, samples doped with poly (4-styrenesulfonate) (PSS) as a dopant to poly (3,4-ethylenedioxythiophene) are coated with electrodes or antistatic materials, It has excellent applicability.

Accordingly, the inventors of the present invention have studied a technique for designing a noise prevention film using a conductive polymer doped with a novel dopant instead of a conventionally well-known conductive polymer doped with a dopant. Thus, the present invention has been completed.

An object of the present invention is to provide a touch screen input device having an excellent noise preventing effect, and more specifically, to provide a touch screen input device having a noise preventing effect by using a conductive polymer using a novel dopant as a noise preventing film .

The touch screen input device according to the present invention includes a noise preventing film, and the sheet resistance of the noise preventing film is 150 to 500? / Sq.

The touch screen input device according to the present invention includes a noise prevention film using a conductive polymer having a low sheet resistance, thereby providing excellent noise reduction effect, excellent visibility, and enhanced sensitivity of a touch screen.

1 to 4 are sectional views of a touch screen input device according to a preferred embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, a touch screen input device according to the present invention will be described in detail.

The touch screen input device of the present invention includes a noise preventing film, and the noise preventing film includes a conductive polymer using a novel dopant, so that the sheet resistance is 150 to 500? / Sq.

That is, the conductive polymer used in the present invention is a random copolymer having a unit structure represented by the following formula (1) and is doped with a polycellulose sulfonate having at least one sulfonate group in the copolymer.

[Formula 1]

Here, where R is _{-H, - (CH 2 CH 2} ) -OH, -CH 2 CH 2 OCH 2 CH (OH) CH 2 SO 3 H, -CH 2 CH 2 OCH 2 CH (OH) CH 2 O -aC ₁₈ H ₃₇ , and a is one or more.

The conductive polymer included in the noise preventing film of the present invention uses the poly cellulose sulfonate as the dopant, thereby increasing the crosslinking density of the conductive polymer and improving the electrical conductivity and thermal stability. Hereinafter, the constituent elements of the conductive polymer composition of the present invention will be described in detail.

First, the conductive polymer of the present invention is an electrically conductive polymer having one π-electron per carbon atom, and generally has a molecular weight of about 10,000 or more. The conductive polymer is advantageous in that it is lightweight and has high flexibility as compared with ITO, which is generally used as a conventional transparent electrode.

The dopant refers to a substance which acts as a charge carrier by adding or removing a charge to a part of the? Orbitals of the conductive polymer of the present invention. The dopant is generally added to impart conductivity to the conductive polymer. The doping of a conducting polymer to form a charge carrier is thus referred to as doping. More specifically, when charge is provided to the conductive polymer, it is referred to as n-type doping. When charge is removed from the conductive polymer, it is referred to as p-type doping.

That is, the conductive polymer included in the noise preventing film used in the present invention is a random copolymer having a unit structure represented by the following formula (1), and is doped by using a polycellulose sulfonate having at least one sulfonate group in the copolymer, The electrical conductivity is high and the thermal stability is increased.

[Formula 1]

Here, where R is _{-H, - (CH 2 CH 2} ) -OH, -CH 2 CH 2 OCH 2 CH (OH) CH 2 SO 3 H, -CH 2 CH 2 OCH 2 CH (OH) CH 2 O -aC ₁₈ H ₃₇ , and a is one or more.

The specific structure of the polycellulose sulfonate represented by Formula 1 is shown in Formula 1-1.

[Formula 1-1]

When the poly-cellulose sulfonate of Formula 1 (or Formula 1-1) dissolves in water, Na + ions are dissociated as shown in Reaction Scheme 1 below, and H + ions are covalently bonded to sulfonate groups to form sulfonic acid groups.

[Reaction Scheme 1]

Hereinafter, the principles of the improvement of the electrical conductivity and the thermal stability of the conductive polymer according to the doping of the poly cellulose sulphonate will be described in detail by way of example.

As shown in the following Reaction Scheme 2, when the conductive polymeric monomer ethylenedioxythiophene (EDOT) is oxidatively polymerized, the sulfonate group anion of the poly (3,4-ethylenedioxythiophene) and the sulfonate group anion of the poly- They are attracted to each other by manpower and form a long chain.

[Reaction Scheme 2]

At this time, since the poly-cellulose sulfonate contains a hydroxyl group (-OH), hydrogen bonds are generated between the poly-cellulose sulfonate molecules, thereby increasing the cross-linking density of the conductive polymer chains.

Accordingly, the distance between the poly (3,4-ethylenedioxythiophene) conductive polymers is shortened, and the electrical conductivity of the conductive polymer composition is improved.

In addition, since the cross-linking density between the conductive polymer chains is high, the stability of the molecular structure is increased, so that even when heat is applied, the polymer chain is less deformed and electrical characteristics can be maintained. This effect occurs not only in the exemplified poly (3,4-ethylenedioxythiophene) conductive polymer but also in other conductive polymers.

Here, the conductive polymer doped with the polycellulose sulfonate of the present invention may be any one of polythiophene type, polypyrrole type, polynetylene type, polyaniline type, and polyacetylene type.

In this case, the polythiophene conductive polymer is preferably poly (3,4-ethylenedioxythiophene). Poly (3,4-ethylenedioxythiophene) / polycellulose sulfonate has an advantage of high electrical conductivity, excellent thermal stability, and good transparency.

The transmittance of the noise preventive film of the present invention including the above-described dopant-doped conductive polymer is 88% or more.

Meanwhile, the touch screen input device including the noise prevention film of the present invention may have various embodiments. Among them, FIGS. 1 to 3 are sectional views of a touch screen input device according to a preferred embodiment of the present invention.

1, a touch screen input device 100 according to the present invention includes a window panel 10 receiving a signal, a first adhesive layer 20 applied to one surface of the window panel 10, A conductive layer 30 applied to one surface of the adhesive layer 20, a second adhesive layer 40 applied to one surface of the conductive layer 30, and a noise preventive layer (not shown) coated on one surface of the second adhesive layer 50).

Here, the conductive layer 30 and the second adhesive layer 40 may be plurally formed according to requirements of the touch panel.

2, the touch screen input device according to the present invention includes a third adhesive layer 60 applied to one side of the noise prevention film 50 and an image display device (not shown) attached to one side of the third adhesive layer 60 70).

Meanwhile, the present invention includes a case where the window panel is an electrode-integrated type, in which case a separate conductive film is not required. 3 is a cross-sectional view of a touch screen input device according to a preferred embodiment of the present invention when the window panel is an electrode-integrated type. A first adhesive layer 20 applied to one surface of the electrode-integrated window panel 11, and a noise prevention film 50 applied to one surface of the first adhesive layer, using the conductive polymer, have.

4, the touch screen input device according to the present invention includes a second adhesive layer 40 applied to one side of the noise prevention film 50, an image display device 70 attached to one side of the second adhesive layer, As shown in FIG.

The window panel 10 receives a signal from a user's body or a specific object and is disposed at an outermost position of the touch screen input devices 100, 200, 300, and 400.

Since the window panel 10 is disposed at the outermost periphery, the window panel 10 must have durability to protect the touch screen input devices 100, 200, 300, and 400 from external mechanical impact. In addition, the window panel 10 must have transparency so that the user can recognize the image provided by the image display device 70.

The window panel 10 may be an electrode-integrated type. As shown in FIG. 3, the electrode-integrated window panel 11 does not require a separate conductive film.

In consideration of the above-mentioned points, the window panel 10 may be made of polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone Type olefin polymer (COC), glass or tempered glass.

The first adhesive layer 20 serves as a spacer for bonding the window panel 10 and the conductive film 30 and insulating the conductive film and is applied to one side of the window panel 10. In addition, a transparent material must be interposed so that the user can recognize the image provided by the image display device 70. [ In consideration of such insulating properties and transparency, it is preferable to use an optical transparent adhesive (OCA) as the first adhesive layer.

The conductive layer 30 serves to recognize a signal received from the window panel 10 and is coated on one side of the first adhesive layer 20.

In the present invention, the conductive film 30 uses an ITO film or a conductive polymer film. The method for forming the conductive film 30 is not particularly limited, but it is preferable to coat the conductive film 30 by inkjet printing, gravure printing, offset printing, or silk screen printing.

The second adhesive layer 40 is applied to one side of the conductive film 30 by bonding the conductive film 30 and the noise prevention film 50 together and serving as a spacer for insulating the conductive film.

A transparent material must be interposed so that the user can recognize the image provided by the image display device 70 like the first adhesive layer. In consideration of such insulating properties and transparency, it is preferable to use an optical transparent adhesive (OCA) as the second adhesive layer 40.

As described above, the noise preventing film 50 includes a conductive polymer using a novel dopant, and thus has a sheet resistance of 150 to 500? / Sq.

When the sheet resistance is less than the above range, there is a problem of malfunction due to a sensitive response to the touch sensor portion, and when the sheet resistance is more than the above range, there is a problem that the noise prevention efficiency is inferior.

In order to satisfy the sheet resistance value, it is preferable that the conductive polymer included in the noise prevention film 50 of the present invention is poly-3,4-ethylenedioxythiophene (PEDOT) doped with poly-cellulose sulfonate.

On the other hand, the transmittance of the noise prevention film 50 is 88% or more, which is excellent in visibility.

The third adhesive layer 60 serves to attach the image display device 70 to the noise prevention film 50. Here, the third adhesive layer 60 should be provided with a transparent material so that the user can recognize the image provided by the image display device 70 like the first and second adhesive layers. In consideration of such insulating properties and transparency, it is preferable to use an optical transparent adhesive (OCA) as the third adhesive layer 60.

The image display device 70 provides an image that can be recognized by a user, and may be any liquid crystal display device that can be generally used in a touch-screen input device.

Example

Example 1

Water, 3,4-ethylenedioxythiophene, and polycellulose sulfonate were placed in a round 100 ml reaction vessel, and the mixture was stirred and sonicated for 30 minutes to prepare a conductive polymer monomer solution. At this time, the composition ratio of the conductive polymer monomer solution was 97 parts by weight of water, 1 part by weight of 3,4-ethylenedioxythiophene and 2 parts by weight of polycellulose sulfonate based on 100 parts by weight of the conductive polymer monomer solution.

Next, 14.08 mmol of an oxidizing agent Fe ₂ (SO ₄ ) ₃ 5H ₂ O was added to the conductive polymer monomer solution, and the mixture was oxidatively polymerized at 25 ° C for 3 hours to obtain poly (3,4-ethylenedioxythiophene) / poly Cellulose sulfonate (PEDOT / PCS) conductive polymer composition was prepared. The conductive polymer composition was coated on a base member and dried in an oven at 100 ° C for 2 minutes to prepare a conductive film, which was used as a noise prevention film.

Comparative Example 1

The same procedure as in Example 1 was carried out except that polystyrene sulfonate was added instead of poly cellulose sulfonate as a dopant. The composition ratio of the conductive polymer monomer solution was 96.5 parts by weight of water, 1 part by weight of 3,4-ethylenedioxythiophene and 2.5 parts by weight of polystyrene sulfonate based on 100 parts by weight of the conductive polymer monomer solution.

The conductive polymer composition was coated on a base member and dried in an oven at 100 ° C for 2 minutes to prepare a conductive film, which was used as a noise preventing film.

Comparative Example 2

A conventional ITO film was used as a noise preventing film.

evaluation

The touch screen input device including the noise preventing film manufactured according to the above embodiments and the comparative example was manufactured according to a conventional method and the noise preventing efficiency according to the sheet resistance was measured and shown in Table 1 below.

Example 1 Comparative Example 1 Comparative Example 2 Sheet resistance 270 Ω / sq 350 Ω / sq 345 Ω / sq Noise reduction efficiency [dB] 75 60 65

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Accordingly, the true scope of the present invention should be determined by the following claims.

Claims (14)

A touch screen input device comprising a noise prevention film,
The sheet resistance of the anti-noise film is a touch screen input device, characterized in that 150 ~ 500 Ω / sq.
A window panel for receiving a signal;
A first adhesive layer applied to one surface of the window panel;
A conductive film coated on one surface of the first adhesive layer;
A second adhesive layer applied to one surface of the conductive film; And
A touch screen input device comprising a noise prevention film using a conductive polymer applied to one surface of a second adhesive layer,
The sheet resistance of the anti-noise film is a touch screen input device, characterized in that 150 ~ 500 Ω / sq.
An electrode-integrated window panel for receiving a signal;
A first adhesive layer applied to one surface of the window panel;
A touch screen input device comprising a noise prevention film using a conductive polymer applied to one surface of the first adhesive layer,
The sheet resistance of the anti-noise film is a touch screen input device, characterized in that 150 ~ 500 Ω / sq.
4. The method according to any one of claims 1 to 3,
Wherein a transmittance of the noise prevention film is 88% or more.
4. The method according to any one of claims 1 to 3,
Wherein the conductive polymer included in the noise barrier layer is a random copolymer having a unit structure represented by the following formula (1), and is doped with a polycellulose sulfonate having at least one sulfonate group in the copolymer.

[Formula 1]

Here, where R is _{-H, - (CH 2 CH 2} ) -OH, -CH 2 CH 2 OCH 2 CH (OH) CH 2 SO 3 H, -CH 2 CH 2 OCH 2 CH (OH) CH 2 O -aC ₁₈ H ₃₇ , and a is one or more.
4. The method according to any one of claims 1 to 3,
The conductive polymer included in the anti-noise film is a poly-3,4-ethylenedioxythiophene (PEDOT) doped with polycellulose sulfonate.
The method of claim 2,
A third adhesive layer applied to one surface of the noise prevention film; And
An image display device attached to one surface of the third adhesive layer;
The touch screen input device further comprising:
The method of claim 2,
The window panel may be formed of a material selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES), cyclic olefin polymer And the reinforcing glass.
The method of claim 2,
Wherein the first adhesive layer and the second adhesive layer are optical transparent adhesives.
8. The method of claim 7,
Wherein the third adhesive layer is an optical transparent adhesive.
The method of claim 3, wherein
A second adhesive layer applied to one surface of the noise prevention film; And
An image display device attached to one surface of the second adhesive layer;
The touch screen input device further comprising:
The method of claim 3, wherein
The window panel may be formed of a material selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES), cyclic olefin polymer And the reinforcing glass.
The method of claim 3, wherein
Wherein the first adhesive layer is an optical transparent adhesive.
12. The method of claim 11,
Wherein the second adhesive layer is an optical transparent adhesive.

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