KR20080063194A - Method of forming a touch panel and a conductive layer of the touch panel - Google Patents

Abstract

The present invention discloses a touch panel. The touch panel according to the present invention includes a first substrate and a second substrate disposed to face each other up and down, a first conductive layer formed on a lower surface of the first substrate, and a second conductive layer formed on an upper surface of the second substrate. At least one of the first conductive layer and the second conductive layer comprises a carbon nanotube layer, the weight per unit area of the carbon nanotube layer is 0.1 to 10 ㎍ / ㎠ and the carbon nanotube layer The carbon nanotubes occupy an area ratio of 10 to 40%.

Description

Touch panel and method for forming electric conduction layers of there of}

The present invention relates to a touch panel, and more particularly, to a touch panel in which the transparent conductive layer is made of carbon nanotubes, which are conductive nanomaterials.

The touch panel is located on the screen of displays such as liquid crystal display (LCD), plasma display panel (PDP), organic light emitting diodes (OLED), cathode-ray tube (CRT), and when a command appears on the screen of the display, A signal input device in which a position signal is input by pressing or touching a command with a pen or a pen.

Indium tin oxide (ITO), which is a conductive metal oxide, is mainly used as a conductive material of a transparent conductive layer constituting a conventional touch panel. ITO exhibits excellent conductivity even when coated with a thin film of 100 nm or less, and has excellent optical properties such as light transmittance in the visible region and environmental resistance.

However, the ITO transparent conductive layer has a weak property of ITO itself. Therefore, when the ITO transparent conductive layer is repeatedly pressed by the user, there is a problem that it is difficult to restore the original state.

In addition, the price of ITO is rising due to the shortage of indium used as a material of ITO. Therefore, since the price of the ITO transparent conductive layer using ITO is also rising, manufacturing cost of a touchscreen will rise.

In addition, since the ITO transparent conductive layer uses expensive equipment such as vacuum deposition and etching in the manufacturing process, it is economically low, and there is a problem such as environmental pollution because it has to use corrosive chemicals.

In order to solve the above problems, a method of forming a transparent conductive layer with a metal oxide such as ITO, IZO, ITZO, ATO, AZO, ZnO, or the like can be considered. However, this method suffers from problems such as high surface resistance, crystallization and etching difficulties.

Recently, organic conductive polymers, which are highly flexible conductive materials, have been used to overcome the low curvature limit of the ITO transparent conductive layer. However, the organic conductive polymer conductive film has a high surface resistance, low light transmittance, and low thermal stability, which makes it difficult to apply to an actual touch panel.

An object of the present invention is to provide a touch panel having a transparent conductive layer having high flexibility, low surface resistance, and high light transmittance.

Therefore, the touch panel according to the embodiment of the present invention includes a first substrate and a second substrate disposed to face each other up and down, a first conductive layer formed on a lower surface of the first substrate, and an upper surface of the second substrate. And a second conductive layer formed on the substrate, wherein at least one of the first conductive layer and the second conductive layer is formed of a carbon nanotube layer, and the weight per unit area of the carbon nanotube layer is 0.1 to 10 µg / cm 2. In addition, the carbon nanotubes occupy an area ratio of 10 to 40% in the carbon nanotube layer.

A first substrate; First and second conductive layers formed on the bottom and top surfaces of the first substrate, respectively; An electrode layer formed on an upper surface of the first substrate and configured to apply a voltage to the first conductive layer or the second conductive layer; And a signal transmission member for transmitting an electrical signal generated from the electrode layer to the outside, wherein at least one of the first conductive layer and the second conductive layer is formed of a carbon nanotube layer.

A method of forming a conductive layer on at least the first substrate constituting the touch panel, the method comprising preparing a carbon nanotube dispersion aqueous solution, and coating the carbon nanotube dispersion aqueous solution on an intermediate base plate having a plurality of pores formed up and down And vacuuming the intermediate base plate to which the carbon nanotube dispersion aqueous solution is applied, so that only carbon nanotubes in the carbon nanotube dispersion aqueous solution remain on the intermediate base plate, and the carbon nanotubes formed of carbon nanotubes on the intermediate base plate. Forming a tube layer and transferring a carbon nanotube layer disposed on the intermediate base plate onto at least the first substrate.

As described above, the touch panel according to the present invention forms the first conductive layer or the second conductive layer as a carbon nanotube layer having high flexibility, so that the touch panel can be easily restored to its original state even if repeatedly pressed by the user. .

In addition, the touch panel is formed of a carbon nanotube layer having high light transmittance and excellent conductivity by forming the first conductive layer or the second conductive layer, thereby providing a touch panel having excellent optical specificity and excellent operating performance.

In addition, the portable device provided with the touch panel of the present invention has the effect of increasing the active area than the portable device provided with the conventional touch panel.

In addition, the carbon nanotube layer constituting the first conductive layer or the second conductive layer of the touch panel does not use expensive equipment such as vacuum deposition or etching during the manufacturing process, and thus is economical and does not use corrosive chemicals. There is an effect of not causing contamination or the like.

In addition, the touch panel uses a carbon nanotube layer instead of ITO as the first conductive layer or the second conductive layer, so that the manufacturing cost of the touch panel does not have to increase even if the ITO price increases due to the lack of indium, which is a raw material of the ITO. There is.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a touch panel according to an embodiment of the present invention, Figure 2 is a side view of the touch panel shown in FIG. 1 is an exploded perspective view of a three-wire resistive touch panel among touch panels. 1 and 2, the touch panel 100 includes a first substrate 120, a second substrate 130, a first conductive layer 121, and a second conductive layer 131. .

The first substrate 120 and the second substrate 130 are disposed to face each other up and down. The first substrate 120 is where the user is pressed by a hand or a stylus pen. Therefore, the first substrate 120 should be a material restored to its original state, and it is preferable to use a material having a predetermined or more elastic force. For example, the first substrate 120 may be made of a transparent PET film.

Hard coating, anti-glare coating, anti-reflection coating, or the like may be used alone or in combination on the upper surface of the first substrate 120 to cope with abrasion or impact due to contact. It can be formed as.

The second substrate 130 is disposed on the display panel, not shown, and the image output from the display panel passes through the second substrate 130. The second substrate 130 for this purpose is preferably formed of a material that can pass through the image without passing through the display panel without loss. Accordingly, the second substrate 130 may be formed of a glass substrate or a transparent plastic substrate having a thickness of 100 μm˜5 mm.

On the other hand, the upper direction is defined in the Z-axis direction for convenience of description, the lower direction is defined in the -Z axis direction.

Meanwhile, the first substrate 120 is defined as a substrate located above the second substrate 130 for convenience of description, but a substrate located above the two substrates may be defined as the second substrate 120. .

The first conductive layer 121 is formed on the lower surface of the first substrate 120, and the second conductive layer 131 is formed on the upper surface of the second substrate 130. The first conductive layer 121 or the second conductive layer 131 may be coated with a uniform thickness on the entire surface of the first substrate 120 or the second substrate 130 or may be patterned in a specific shape. The first conductive layer 121 and the second conductive layer 131 are in contact with each other by the pressure applied to the first substrate 120, and the first conductive layer 121 and the second conductive layer 131 are contacted by the contact. The resistance value between) changes.

At least one of the first conductive layer 121 and the second conductive layer 131 for this purpose is made of a carbon nanotube layer. Since the first conductive layer 121 is mostly pressed by the pressure applied to the first substrate 120, the first conductive layer 121 is restored to its original position after being deformed without being deformed by pressing. It must be resilient to do so. Therefore, it is advantageous to make the first conductive layer 121 made of a carbon nanotube layer having excellent flexibility.

Meanwhile, when the first conductive layer 121 is formed of a carbon nanotube layer, the second conductive layer 131 may be formed of any one selected from the group consisting of metal oxides such as ITO, IZO, ITZO, ATO, and AZO.

The touch panel 100 may further include an adhesive layer 140. The adhesion layer 140 is formed between the carbon nanotube layer and the first substrate 120 or the second substrate 130 on which the carbon nanotube layer is formed, and the carbon nanotube layer is formed on the first substrate 120 or Couple to the second substrate 130.

The material of the adhesive layer 140 for this may be any one selected from acrylic based, silicone based, urethane based materials. The adhesive layer 140 may be spray coated, spin-oated, roll coated, knife coated, or knife coated on the first substrate 120 or the second substrate 130. It may be formed by any one method selected from dip coating and bar coating.

On the other hand, it is preferable that the thickness of the adhesive layer 140 is formed to be 1 nm to 500 nm so as to obtain a suitable adhesive force desired by the manufacturer.

In addition, since the adhesive layer 140 is formed between the carbon nanotube layer and the first substrate 120 or the second substrate 130 on which the carbon nanotube layer is formed, the user repeatedly uses the touch panel with a stylus pen. Even if the carbon nanotube layer is not separated from the first substrate 120 or the second substrate 130.

In addition, the adhesive layer 140 has a greater adhesive force between the carbon nanotube layer and the first substrate 120 or the second substrate 130 on which the carbon nanotube layer is formed, than the touch panel on which the adhesive layer is not formed. To improve the durability of the touch panel 100 according to an embodiment of the present invention.

In addition, the adhesion layer 140 allows the carbon nanotube layer to be uniformly formed on the first substrate 120 or the second substrate 130.

In addition, the adhesive layer 140 having excellent flexibility acts as a shock absorber between the carbon nanotube layer and the first substrate 120 or the second substrate 130 on which the carbon nanotube layer is formed. Allows you to feel your handwriting.

Carbon nanotube layer is a plurality of carbon nanotube strands are tangled with each other to form a thin film. In this case, the carbon nanotube layer is spray coated, spin-oated or rolled carbon nanotubes of the carbon nanotube dispersion solution or powder on the first substrate 120 or the second substrate 130. Roll coating, Knife coating, Dip coating, Bar coating, Inkjet printing, Screen printing, Gravure printing, Heat to It can be formed through transfer coating and vacuum coating.

Meanwhile, another method of forming the carbon nanotube layer of the touch panel is formed by forming a carbon nanotube layer on a separate base plate and transferring the carbon nanotube layer to the first substrate 120 or the second substrate 120. can do. A detailed description of the method of forming the carbon nanotube layer of the touch panel in this manner will be described later.

In order to lower the surface resistance of the touch panel and to increase the light transmittance according to the preferred embodiment of the present invention, the weight per unit area of the carbon nanotube layer is 0.1 to 10 µg / cm 2, and the carbon nanotubes in the carbon nanotube layer. It is preferable that the area ratio which they occupy consists of 10 to 40%.

The weight per unit area of the carbon nanotube layer is defined as the amount of carbon nanotubes contained in the dispersion solution divided by the filtering area of the membrane material. The filtering area corresponds to the area of the carbon nanotube layer obtained by filtering the dispersion solution containing carbon nanotubes to the membrane material.

For example, the process of calculating the weight per unit area of the carbon nanotube layer, the amount of dispersion solution supplied to the membrane material is 1ml, the amount of carbon nanotubes contained in 1ml dispersion solution is 15㎍, If the membrane material has a filtering area of 11.3411 cm 2, the weight per unit area of the carbon nanotube layer is 1.32 μg / cm 2 divided by 15 μg divided by 11.3411 cm 2.

The area ratio (hereinafter referred to as "area ratio") of the carbon nanotubes in the carbon nanotube layer is measured by looking at the surface of the touch panel with an atomic force microscope (AFM).

The reason for setting the area ratio to 10 to 40% can be more clearly understood by the data shown in Table 1 below.

Table 1 is a table measuring how the permeability of the carbon nanotube layer and the sheet resistance of the carbon nanotube layer become different at each area ratio.

As shown in Table 1, as the area ratio increases from 10% to 40%, the transmittance decreases from 85% to 75%, and the sheet resistance decreases from 900 Ω / sq to 200 Ω / sq. If the area ratio exceeds 40%, the permeability of the carbon nanotube layer is too low, which may be disadvantageous for application to a general touch panel.

The reason is that the touch panel is located on the screen of a display such as a liquid crystal display (LCD), a plasma display panel (PDP), organic light emitting diodes (OLED), a cathode-ray tube (CRT), and the like. Is a signal input device that inputs a position signal by pressing or touching a command with a finger or a pen.

When the transmittance of the carbon nanotube layer is less than 70%, the brightness of the image output from the screen of the display is transmitted to the user with a considerable amount of attenuation so that users cannot enjoy the bright image.

If the area ratio is less than 10%, the surface resistance value becomes too high, which may be disadvantageous for application to a general touch panel. This is because the higher the surface resistance value, the higher the driving voltage must be.

For the above reasons, the area ratio of carbon nanotubes in the carbon nanotube layer is preferably 10 to 40%.

Area ratio of carbon nanotubes to carbon nanotube layer (%) Permeability of Carbon Nanotube Layer in Visible Light 550nm (%) Sheet Resistance of Carbon Nanotube Layer (Ω / sq) 10% 85% 900 Ω / sq 20% 82% 500 Ω / sq 30% 79% 350 Ω / sq 40% 75% 200 Ω / sq

The change in permeability of the carbon nanotube layer according to the area ratio can be confirmed from the photographs shown in FIGS. 3 to 6. 3 to 6 is a photograph taken by enlarging the carbon nanotube layer prepared after manufacturing by changing the area ratio to 40%, 30%, 20%, 10%. Here, the gray strands are carbon nanotubes 15.

As shown in FIGS. 3 to 6, when the area ratio is reduced from 40% to 10%, the carbon nanotube layer has more empty space than the area filled with carbon nanotubes. Accordingly, the permeability of the carbon nanotube layer can be increased.

On the other hand, the carbon nanotube layer preferably has a haze of 5% or less. Since the touch panel 100 is disposed on the display panel, when the turbidity of the touch panel 100 is high, an image transmitted from the display panel may not be clearly seen by the user.

In addition, the carbon nanotube layer preferably has a sheet resistance uniformity of 10% or less. The sheet resistance uniformity is the value of the sheet resistance divided by the average of the sheet resistances, and the sheet resistance uniformity of 10% or more means that the sheet resistance is not uniform. Therefore, when the surface resistance uniformity is 10% or more, when the first conductive layer and the second conductive layer are in contact with each other, the error range of the resistance value increases when the control unit not shown measures the changed resistance value. It requires a wider measuring range.

In addition, the carbon nanotube layer may be formed to have a thickness of 10 nm to 300 nm. If the thickness of the carbon nanotube layer is less than 2nm is insufficient to obtain the desired conductivity, if it exceeds 300nm there is a problem that the light transmittance of the electrode is lowered. However, the carbon nanotube layer according to an embodiment of the present invention is made of a thickness of 2nm to 300nm, it has a high conductivity and excellent light transmittance.

Carbon nanotubes are materials in which one carbon atom is bonded to three different carbon atoms to form a hexagonal honeycomb graphene sheet (graphene sheet) wound in a tube shape. Carbon nanotubes have an excellent resistivity of about 10 ⁻⁴ Ω㎝ to 10 ^-3 Ω㎝, and are 100 times stronger than steel, chemically stable, and have a large surface area.

On the other hand, the carbon nanotubes constituting the carbon nanotube layer can be used both single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, but preferably made of single-walled carbon nanotubes with excellent electrical conductivity. .

The touch panel 100 may further include an electrode layer 151, an insulating layer 152, and a spacer 160 together with the first conductive layer 121 and the second conductive layer 131.

The electrode layer 151 is formed on the bottom surface of the first conductive layer 121 or the top surface of the second conductive layer 131, respectively. The electrode layer 151 generates an electric field in the first conductive layer 121 or the second conductive layer 131.

The insulating layer 152 is interposed between the first conductive layer 121 and the second conductive layer 131 to prevent conduction between the first conductive layer 121 and the second conductive layer 131, The insulating layer 152 combines the first conductive layer 121 and the second conductive layer 131. The insulating layer 152 may be made of an insulating double-sided tape.

The signal transmission member 153 serves to transmit the electrical signal generated from the electrode layer 151 to the controller not shown. The controller, which is not shown, analyzes an electrical signal transmitted from the signal transmission member 153 to detect at which point the contact occurs between the first conductive layer 121 and the second conductive layer 131.

The spacers 160 are formed on one surface of the lower surface of the first conductive layer 121 and the upper surface of the second conductive layer 131. When the spacers 160 are in contact with a region of the first conductive layer 121 and the second conductive layer 131 by the pressing of the first substrate 120, the user inputs the pressing of the first substrate 120. Function to improve accuracy.

The driving process of the resistive touch panel as described above is as follows.

A current having a predetermined voltage is supplied to the first electrode layer 151a and the second electrode layer 151b so that a current flows in the first conductive layer 151a and the second conductive layer 151b. In this state, when a certain area on the first substrate 120 is pressed with a finger, the first conductive layer 151a and the second conductive layer 151b come into contact with each other. In the region where the first conductive layer 151a and the second conductive layer 151b are pressed, the resistance value is changed, and the current value or the voltage value is changed according to the changed resistance value. Next, the electric signal having the changed current value or voltage value is transmitted to the outside of the touch panel 100 through the signal transmission member. The controller, not shown, recognizes the position where the finger touched the electric signal.

FIG. 7 is a side view illustrating a state in which a bezel is added to the touch panel shown in FIG. 2.

As shown in FIG. 7, a bezel 170 is provided in a general mobile device in which the touch panel 100 is installed. The bezel 170 is for performing the following functions.

The touch panel 100 operates as the user presses the first substrate 120 with a finger as described above. However, when the user presses the first substrate 120, the boundary region between the portion supported by the insulating layer 152 and the portion not supported may be pressed. As a result, stress is concentrated in the boundary region, which may damage the first conductive layer 121 located above the insulating layer 152. To prevent this, the bezel 170 is installed to cover the upper portion of the boundary region. The boundary region is called a dead zone because it cannot be used in the touch panel 100.

Since the bezel 170 is installed to cover the dead zone D of the touch panel 100, the touch panel 100 has a viewing area V and an active area A. FIG. The active area A corresponds to an area that a user can actually input.

As described above, the first conductive layer 121 is made of a carbon nanotube layer having superior flexibility and durability than the ITO transparent conductive layer. Accordingly, the first conductive layer 121 can make the installation area of the bezel smaller than that of the ITO transparent conductive layer. As a result, the active area A can be increased.

Hereinafter, the results of experiments using the touch panel 100 according to the exemplary embodiment of the present invention shown in FIG. 1 will be described. The experiment measured light transmittance, surface resistance, adhesion stability, operation error rate, durability of hard coating layer, impact resistance test of touch panel, environmental durability test of touch panel, contact reaction speed, and resistance value change rate by folding.

The light transmittance of the carbon nanotube layer is 70% or more in visible light (550 nm) measured using an ultraviolet-visible light spectrometer. The surface resistance of the carbon nanotube layer measured using a surface resistance meter is 2000 kW / sq or less. In addition, the uniformity (surface resistance standard deviation / average) of surface resistance is 10% or less.

The adhesion stability of the carbon nanotube layer is 5B (there is no carbon nanotube layer removed at all) as measured by a tape test (ASTM D 3359-02).

The motion error rate experiment was conducted assuming a 110g load corresponding to the weight of a human finger as the operating pressure of the touch panel. In order to measure the linear accuracy, the test software was used to confirm the error rate of the touch coordinates of the X to Y axes, and the results were within 2%.

The durability of the hard coating layer is for measuring the hardness of the hard coating layer formed on the upper surface of the first substrate 120. The durability of the hard coating layer was measured using a pencil hardness tester (ISO-15184), and the hardness of 3H was measured. Surface durability measurements were performed 10,000 linear reciprocating movement of the hard coating layer at a speed of 100 ± 15 mm / s using a stylus pen having a load of 250gf, the wear did not occur on the surface of the hard coating layer.

In order to measure the reliability of the touch panel 100, the letter writing test and the rubber stroke test were repeatedly performed 30 million times in a 20 mm × 20 mm grid. Test conditions were performed using a pen plotter at a speed of 100 mm / s to 2 times / second, respectively, and the test results showed no change on the surface of the touch panel.

In the impact resistance test of the touch panel 100, a free fall of a steel sphere having a radius of 10 mm over the fixed touch panel 100 at a height of 15 cm did not show breakage and electrical characteristics of the touch panel 100. .

Environmental durability test of the touch panel 100 was carried out high temperature test, low temperature test, humidity test, thermal shock test, chemical resistance test.

In the high temperature test, the touch panel 100 was placed in a device maintaining a temperature of 70 ± 2 ° C. and a relative humidity of 40 to 50% for 120 hours, and then the touch panel 100 sample was measured after standing at room temperature for 4 hours. As a result of the measurement, the appearance and electrical characteristics of the touch panel 100 were not changed. In the low temperature test, the panel of the touch pad 100 was put into a device maintaining -25 ± 2 ° C. for 120 hours, and then the sample of the touch panel 100 was measured after standing at room temperature for 4 hours. Got.

In the humidity test, the touch panel 100 sample was put into a device maintaining 60 ± 2 ° C. and a relative humidity of 90 to 95% for 96 hours, and the touch panel 100 sample was measured after being left at room temperature for 4 hours to prevent moisture. It was. The thermal shock test was performed for 10 minutes in a device having a temperature change of 30 minutes at -40 ± 2 ° C. and 30 minutes at 80 ± 2 ° C., and then maintained at room temperature for 4 hours or more, and then sampled the touch panel 100. Was measured. The test results of the humidity test and the thermal shock test did not show the change in appearance and electrical properties in the same way as the results of the high temperature test and the low temperature test.

The chemical resistance test of the surface hard coating layer of the touch panel 100 wiped the surface lightly with methyl alcohol, breathing, and a glass cleaner, and then confirmed that there was no change in the appearance of hard coating.

The contact reaction speed of the touch panel 100 did not exceed 15 ms after the touch.

Signal transmission members 153a and 153b of the touch panel 100 are connected to an external control unit (not shown). With respect to the operation of the touch panel 100, the presence or absence of a touch input and the coordinate detection at the time of the touch input were confirmed, and an excellent operation result was confirmed.

The change rate of the resistance value due to folding compared to the initial resistance value of the first conductive layer 151a or the second conductive layer 151b made of carbon nanotubes was measured to be 0.3% or less.

8 to 13 illustrate a resistive touch panel and a capacitive touch panel to which a touch panel according to an embodiment of the present invention can be applied. The structures of the various touch panels 200, 300, and 400 are merely examples for structurally describing the method of implementing the present invention, and the present invention is not limited to these embodiments.

8 and 9 illustrate a 5-wire resistive touch panel 200. 8 and 9, the upper layer structure of the touch panel 200 may be formed on the first conductive layer 221 formed on the lower surface of the first substrate 220 and the Y-axis end of the first substrate 220. The first electrode layer 251a and the signal transmission member 253a are provided for the formed signal output.

The lower layer structure of the touch panel 200 includes a second substrate 230, a second conductive layer 231 formed on an upper surface of the second substrate 230, and an X axis and a Y axis of the second conductive layer 231. A second electrode layer 251b formed at an edge and a signal transmission member 253b connected to the second electrode layer 251b are provided.

Here, the signal transmission member 253a of the first electrode layer 251a is disposed so as not to conduct electricity with the signal transmission member 253b of the second electrode layer 251b formed at the X and Y axis edges of the second substrate 230. It is preferable.

10 and 11 illustrate a five-wire resistive touch panel 300 having a changed structure in the 5-wire resistive touch panel 200 of FIG. 8. Referring to FIGS. 10 and 11, the touch panel 300 illustrated in FIG. 10 is identical to the touch panel 200 illustrated in FIG. 8 in that a first conductive layer (not shown) is formed on the bottom surface of the first substrate 320. 351a is disposed, and the second conductive layer 351b is disposed on the upper surface of the second substrate 330. On the other hand, the touch panel 300 of FIG. 10 differs from the touch panel 200 of FIG. 8 in that both the first electrode layer 351a and the second electrode layer 351b are disposed on the second substrate 330.

12 is an exploded perspective view of the capacitive touch panel 400, and FIG. 13 is a side view of the capacitive touch panel 400 of FIG. 12. 12 and 13, the capacitive touch panel 400 includes a first substrate 430, an adhesive layer 440 formed on an upper surface of the first substrate 430, and the adhesive layer 440. And a hard coating layer 470 formed on the first conductive layer 421, an electrode layer 451 formed at an edge of the carbon nanotube transparent conductive layer 421, and a first conductive layer 421 formed on the first conductive layer 421.

The capacitive touch panel 400 distributes a uniform electric field to the touch panel 400 by applying a voltage to the electrode layer 451 of the touch panel 400, and when touching the first substrate 430 with a finger, It works on the principle of recognizing the change in voltage distribution in each current sensor shown.

14 is a perspective view showing a mobile communication terminal having a touch sensor made of a carbon nanotube layer according to an embodiment of the present invention.

Referring to FIG. 14, a keypad 510 is used as a means for inputting a command to the mobile communication terminal 500. The keypad 510 of the mobile communication terminal 500 illustrated in FIG. 14 is provided with a conductive layer not shown therein. When a user's finger contacts the keypad 510, a current change or an electric field is generated in the keypad 510. Electrical changes such as The electrical change is a circuit board (not shown) in the mobile communication terminal 500 analyzes the electrical change, and recognizes that the finger touches the keypad.

Here, in the mobile communication terminal 500 illustrated in FIG. 14, the conductive layer not shown is made of the carbon nanotube layer according to the embodiment of the present invention, so that the carbon nanotube layer may be used as a conductor of the touch sensor.

Meanwhile, the touch panel 200 of FIG. 8 and the touch panels 300 and 400 illustrated in FIGS. 10 and 12 performed the same experiment as the touch panel 100 of FIG. 1. The experiment measured light transmittance, surface resistance, adhesion stability, operation error rate, durability of hard coating layer, impact resistance test of touch panel, environmental durability test of touch panel, contact reaction speed, and resistance value change rate by folding. Experimental results were similar to the touch panel 100 of FIG. 1.

Next, a method of forming a carbon nanotube layer on a first substrate or a second substrate provided in a touch panel according to an embodiment of the present invention will be described in detail. 15 is a flowchart illustrating a method of forming a carbon nanotube layer of a touch panel according to an embodiment of the present invention.

Referring to Figure 15, the method for forming a carbon nanotube layer of the touch panel according to an embodiment of the present invention, the step of preparing a carbon nanotube dispersion aqueous solution (S10), and the middle of the plurality of pores formed up and down Applying the carbon nanotube dispersion aqueous solution on the base plate (S20) and applying a vacuum to the intermediate base plate to which the carbon nanotube dispersion aqueous solution is applied so that only carbon nanotubes in the carbon nanotube dispersion aqueous solution remain on the intermediate base plate. Filtering to form a carbon nanotube layer made of carbon nanotubes on the intermediate base plate (S30) and transferring the carbon nanotube layer disposed on the intermediate baseplate onto a first substrate or a second substrate ( S40).

16 to 18 are diagrams illustrating respective steps of a method of forming a carbon nanotube layer of a touch panel, respectively. Hereinafter, respective steps of the method of forming the carbon nanotube layer of the touch panel according to the exemplary embodiment of the present invention will be described in detail with reference to FIGS. 16 to 18.

On the other hand, the method of forming the carbon nanotube layer of the touch panel is merely for the purpose of illustrating the embodiment of the present invention in detail. The present invention is not limited to those produced by these methods.

First, a carbon nanotube dispersion aqueous solution 14 is prepared. The carbon nanotube dispersion aqueous solution 14 may be triton X-100, sodium salt of dodecylbenzenesulfonic acid (Na-DDBS), cetyl trimethyl ammonium bromide (CTAB), or sodium dodecyl sulfate ( It can be prepared by adding carbon nanotubes to an aqueous solution in which dispersing agents such as SDS and Sodium Dodecyl Sulfate are dissolved and applying ultrasonic waves for 1 to 120 minutes.

In addition, a carbon nanotube organic dispersion solution may be used instead of the carbon nanotube dispersion aqueous solution 14. Carbon nanotube organic dispersion solution, N-methylpyrrolidone (NMP, N-Methylpyrrolidone), o-dichlorobenzene (o-dichlorobenzene), dichloroethane (dimethyl chloride), dimethylformamide (DMF), chloroform (chloroform), etc. Carbon nanotubes may be added to the organic solvent and then prepared by applying ultrasonic waves for 1 to 120 minutes. However, the present invention is not limited to a method of preparing a carbon nanotube dispersion solution or a carbon nanotube organic dispersion solution, and various other methods may be used.

Next, as illustrated in FIGS. 16 and 17, the carbon nanotube dispersion aqueous solution 14 is coated on the intermediate base plate on which the plurality of pores 13 are formed up and down, and the carbon nanotube dispersion aqueous solution 14. The vacuum is applied to the coated intermediate base plate 11 so that only the carbon nanotubes 15 of the carbon nanotube dispersion aqueous solution 14 remain on the intermediate base plate 11.

The intermediate base plate 11 is made of a polymer membrane 12 material, the polymer membrane 12 material preferably has a pore 13 diameter of 0.01㎛ 10㎛. If the diameter of the pores 13 of the polymer membrane 12 is 10 μm or more, the aqueous solution and the carbon nanotubes 15 are removed to the outside through the pores 13. In addition, when the pore 13 of the polymer membrane 12 has a diameter of 0.01 μm or less, it is difficult for the aqueous solution to pass through the pores 13 of the polymer membrane 12.

As such, the polymer membrane 12 serves to remove all or almost all of the material except the carbon nanotubes through the pores of the polymer membrane 12 in the process of forming the carbon nanotube layer. Examples of polymer membranes for this purpose include polycarbonate, polyethylene terephtalate (PET), polyamides, cellulose esters, regenerated cellulose, nylon, polypropylene, polyacrylics. It may be any one selected from the group consisting of ronitrile (Polyacrylonitrile), polysulfone (Polysulfone), polyester sulfone (Polyethersulfone) and polyvinylidene fluoride (Polyvinylidenfluoride).

When the large-area vacuum filtration device 17 is attached to the lower surface of the intermediate base plate 11 as described above, and the carbon nanotube dispersion aqueous solution 14 is vacuum filtered, at least some of the materials except for the carbon nanotubes 15 are preferable. All are removed through the pores 13 of the polymer membrane 12. Thereafter, only the carbon nanotubes 15 strands remain on the intermediate base plate 11, and the carbon nanotubes 15 strands are entangled with each other to form a uniform carbon nanotube layer 16. At this time, the thickness of the carbon nanotube layer 16 formed can be easily adjusted by adjusting the amount of the carbon nanotube dispersion solution to be filtered.

Next, as shown in FIG. 18, the carbon nanotube layer 16 disposed on the intermediate base plate 11 is transferred to the first substrate 120 or the second substrate 130.

The carbon nanotube layer 16 is well dispersed and formed on the intermediate base plate 11, and thereafter, a predetermined number of rows or more are disposed on the front surface of the first substrate 120 or the portion where the pattern of the second substrate 130 needs to be formed. In the state in which the intermediate base plate 11 and the first substrate 120 or the second substrate 130 are in close contact with each other and then separated. Then, the carbon nanotube layer 16 may be formed along a predetermined pattern on the entire surface of the first substrate 120 or on the second substrate 130.

On the other hand, before the carbon nanotube layer 16 is transferred to the first substrate 120 or the second substrate 130, the carbon nanotube layer 16 is first bonded to the adhesive layer, and then the first substrate 120 Alternatively, it may be coupled to the second substrate 130. The adhesive layer is well bonded to the carbon nanotube layer 16 and is also well bonded to the first substrate 120. Thus, the carbon nanotube layer 16 is strongly bonded to the first substrate 120 or the second substrate 130.

The carbon nanotube layer 16 manufacturing method as described above is an easy method for adjusting the area ratio required for the touch panel of the present invention to be used as a general touch panel in the range of 10% to 40%. The area ratio is the area ratio occupied by the carbon nanotubes in the carbon nanotube layer 16 as described above.

To explain the reason, the amount of carbon nanotubes 15 remaining on the intermediate base plate 11 increases or decreases the amount of the carbon nanotube dispersion aqueous solution 14 filtered by the vacuum filtration device 17. It can be controlled by the process of making it. Therefore, the area ratio occupied by the carbon nanotubes in the carbon nanotube layer 16 can be easily adjusted to a predetermined range.

1 is an exploded perspective view of a touch panel according to an embodiment of the present invention.

FIG. 2 is a side view of the touch panel of FIG. 1.

3 to 6 is a carbon nanotube layer prepared by varying the area ratio occupied by carbon nanotubes in the carbon nanotube layer provided in the touch panel of the present invention to 40%, 30%, 20%, 10%, This is a picture taken by magnifying.

FIG. 7 is a side view illustrating a state in which a bezel is added to the touch panel shown in FIG. 2.

8 is an exploded perspective view of a 5-wire resistive touch panel according to another embodiment of the present invention.

9 is a side view of the touch panel of FIG. 8.

FIG. 10 is an exploded perspective view of a 5-wire resistive touch panel in which the structure of the touch panel of FIG. 8 is changed.

FIG. 11 is a side view of the touch panel of FIG. 10.

12 is a perspective view of a capacitive touch panel according to another embodiment of the present invention.

FIG. 13 is a side view of the capacitive touch panel of FIG. 12.

14 is a perspective view showing a mobile communication terminal having a touch sensor made of a carbon nanotube layer according to an embodiment of the present invention.

15 is a flowchart illustrating a method of forming a carbon nanotube layer of a touch panel according to an embodiment of the present invention.

FIG. 16 is a diagram illustrating a step of arranging conductive carbon nanotubes on an intermediate base plate according to an exemplary embodiment of the present invention.

17 and 18 are cross-sectional views illustrating a step of moving a carbon nanotube layer onto a first substrate.

<Description of the code | symbol about the principal part of drawing>

15. Carbon Nanotubes 16. Carbon Nanotubes Layers

120. First substrate 121. First conductive layer

130. Second substrate 131 Second conductive layer

140. Adhesive layer 151. Electrode layer

152. Insulation layer 153 Signal transmission member

160..Spacer

Claims (8)

A first substrate and a second substrate disposed to face each other up and down; And A first conductive layer formed on the lower surface of the first substrate and a second conductive layer formed on the upper surface of the second substrate; At least one of the first conductive layer and the second conductive layer is made of a carbon nanotube layer, the weight per unit area of the carbon nanotube layer is 0.1 to 10 ㎍ / ㎠, carbon nanotubes in the carbon nanotube layer Occupy an area ratio of 10 to 40%. The method of claim 1, An electrode layer formed on a lower surface of the first conductive layer or an upper surface of the second conductive layer and generating an electric field in the first conductive layer or the second conductive layer; An insulating layer disposed between the first conductive layer and the second conductive layer; A signal transmitting member transmitting an electrical signal generated from the electrode layer to the outside; And And a plurality of spacers formed on any one surface of the lower surface of the first conductive layer and the upper surface of the second conductive layer. A first substrate; A first conductive layer and a second conductive layer formed on the bottom surface and the top surface of the first substrate, respectively; An electrode layer formed on an upper surface of the first substrate and configured to apply a voltage to the first conductive layer or the second conductive layer; And And a signal transmission member for transmitting the electrical signal generated from the electrode layer to the outside. At least one of the first conductive layer and the second conductive layer is a touch panel, characterized in that made of a carbon nanotube layer. The method of claim 3, wherein The carbon nanotube layer has a weight per unit area of 0.1 to 10 ㎍ / ㎠, the area ratio occupied by the carbon nanotubes in the carbon nanotube layer is 10 to 40%. The method according to claim 1 or 4, The carbon nanotube layer has a light transmittance of 70% or more and a surface resistance of 2,000 Ω / sq or less. A method of forming a conductive layer on at least a first substrate constituting a touch panel having the structure of claim 1, Preparing a carbon nanotube dispersion aqueous solution; Applying the carbon nanotube dispersion aqueous solution to an intermediate base plate having a plurality of pores formed therethrough; A vacuum was applied to the intermediate base plate to which the carbon nanotube dispersion aqueous solution was applied, and filtered so that only carbon nanotubes in the carbon nanotube dispersion aqueous solution remained on the intermediate base plate, thereby forming a carbon nanotube layer made of carbon nanotubes on the intermediate base plate. Forming; And And transferring the carbon nanotube layer disposed on the intermediate base plate onto at least a first substrate. The method of claim 6, The intermediate base plate is made of a polymer membrane material, the diameter of the pores formed in the polymer membrane is a method for forming a conductive layer of the touch panel, characterized in that 0.01㎛ to 10㎛. The method of claim 7, wherein The polymer membrane may be polycarbonate, polyethylene terephtalate (PET), polyamides, cellulose esters, regenerated cellulose, nylon, polypropylene, polyacrylonitrile Polyacrylonitrile), polysulfone (Polysulfone), polyester sulfone (Polyethersulfone) and polyvinylidene fluoride (Polyvinylidenfluoride) is a method for forming a conductive layer of the touch panel, characterized in that any one selected from the group consisting of.

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