KR20130025564A

KR20130025564A - Transparent conductive layer and manufacturing method thereof

Info

Publication number: KR20130025564A
Application number: KR1020110088941A
Authority: KR
Inventors: 이영일
Original assignee: 주식회사 아모그린텍
Priority date: 2011-09-02
Filing date: 2011-09-02
Publication date: 2013-03-12

Abstract

PURPOSE: A transparent conductive layer and a manufacturing method thereof are provided to simplify a manufacturing process by properly controlling a thickness and a linewidth of a conductive pattern. CONSTITUTION: A conductive pattern(12) is formed by controlling a linewidth and a thickness using conductive ink or conductive paste. The conductive pattern is formed on a transparent substrate(10). The linewidth of the conductive pattern is 30 um or less. The thickness of the conductive pattern is 1 um or more.

Description

Transparent conductive film and manufacturing method thereof

The present invention relates to a transparent conductive film and a method for manufacturing the same, and more particularly, to a transparent conductive film and a method for manufacturing the same, in which the manufacturing process is very simple and inexpensive while satisfying the transparency and conductivity requirements even when using a non-transparent low cost material. It is about.

In general, the transparent conductive film is an essential component of electrical and electronic equipment such as transparent electrodes in various display fields such as application of power for display elements, electromagnetic shielding film of home appliances, LCD, OLED, FED, PDP, flexible display, electronic paper, and touch panel. In addition, inorganic oxide conductive materials such as indium-tin oxide (ITO), antimony-tin oxide (ATO) and antimony-zinc oxide (AZO) are used as the transparent conductive film material which is mainly used.

When the transparent conductive film is manufactured by the sputtering method, ion beam method, or vacuum deposition method, which is commonly used, a conductive film having excellent high conductivity and transmittance can be manufactured, but it is difficult to mass-produce and large-scale the equipment investment cost by vacuum equipment. In particular, there is a limit to a transparent substrate requiring a low temperature process such as a plastic film. In the sputtering process, the transmittance and resistance of the thin film rapidly change as the composition of the transparent conductive film changes according to conditions such as oxygen partial pressure and temperature during deposition.

Accordingly, a method of coating a transparent conductive film by using a wet coating method such as spin coating, spray coating, dip coating, printing, etc., which is suitable for low cost and large size, and then fires is proposed. Korean Patent No. 1999-011487 discloses a transparent conductive film using metal fine particles and a binder. Korean Patent Publication No. 1999-064113 discloses a composition for a transparent conductive film in which hollow microfine fibers are added to tin oxide. Patent No. 2000-009405 discloses a coating solution for forming a transparent conductive light-selective absorption film in which neodymium oxide is added to tin oxide or indium oxide. In addition, Japanese Laid-Open Patent Publication No. 2003-213441 discloses a method for producing a transparent conductive layer forming liquid containing metal fine particles such as gold and silver.

The surface resistance of the transparent conductive film prepared according to the above method is 10 ³ -10 ⁴ Ω / □, the resistance is high, and the surface resistance increases with time due to the change of the surrounding environment. There is a problem that cannot be used as a transparent conductive film has a limit.

In view of this, Korean Patent No. 856508 proposes a transparent conductive film composed of at least one composite multilayer film including a transparent layer using an organic acid metal salt and a conductive layer using a conductive layer forming solution containing a silver complex compound, and a method of forming the same. have.

On the other hand, in recent years, with the rapid increase in the spread of wireless communication terminals such as mobile phones, especially smart phones and note pads, ITO is used as a transparent conductive material for various drive lines and the like for the touch screen used as a display thereof.

The ITO is a recycled metal, and the price is increasing. Since ITO conductive films are formed on the substrate by sputtering or deposition to form desired electrodes and wires, many pollutants are emitted during the patterning process. There is.

In view of this, a silver salt type conductive film produced by pattern exposure of an applied silver halide emulsion to form conductive silver portions to ensure conductivity and openings to ensure transparency is, for example, Japan Japanese Patent Laid-Open Publication Nos. 2004-221564 and 2004-221565.

In order to solve the problem, the conductive film according to the related art includes a moire, and in order to solve the problem, Korean Patent Application Publication No. 2010-129230 discloses a technique of forming a metal mesh pattern by forming a photosensitive silver salt layer on a transparent film substrate and performing an exposure and development process. Proposed.

In addition, Korean Unexamined Patent Publication No. 2010-48931 also discloses a conductive film for a touch panel and a method of manufacturing the same, which can reduce moiré by forming a conductive layer having a silver mesh pattern by exposing and developing a silver salt emulsion layer. .

As described above, since the ITO conductive film or the photosensitive silver salt layer is mainly patterned to form transparent electrodes and wirings, expensive material loss is large, and manufacturing processes such as exposure and development processes are complicated, Excessive amounts of pollutants are emitted during etching or development, or expensive manufacturing equipment such as deposition or sputtering equipment and vacuum rooms are required. Therefore, it is a problem of the present invention to solve these problems of the prior art.

The present inventors have endeavored to solve this problem, and thus, even when a conductive pattern is formed using electrodes and wiring materials that are not transparent, the present invention does not use expensive materials such as ITO by appropriately controlling the line width and thickness of the conductive pattern. While removing the patterning process, a technology for forming a transparent conductive film for a display or a touch screen has been developed.

An object of the present invention is transparent by appropriately controlling the line width and thickness of a conductive pattern printed by a noncontact or contact printing method on a transparent substrate using a conductive ink or conductive paste containing metal nanoparticles as a conductive pattern forming material. Even if a material that is not used is used, a transparent conductive film and a method of manufacturing the same, which satisfies the requirements of transparency (transmittance) and conductivity, are manufactured at a very simple and low cost.

According to an embodiment of the present invention for achieving the above object, the present invention is a transparent substrate; And a conductive pattern formed by adjusting a line width and a thickness of the pattern by a non-contact or contact printing method using a conductive ink or a conductive paste on the transparent substrate, wherein the line width of the conductive pattern is set to 30 μm or less and has a thickness. A transparent conductive film is set to 1 µm or more.

The conductive ink or conductive paste includes nanoparticles made of any one or two or more alloys selected from the group consisting of Ag, Pt, Au, Mg, Al, Zn, Fe, Cu, Ni, and Pd.

Forming the conductive pattern on the transparent substrate by a non-contact or contact printing method using a conductive ink or a conductive paste; And heat treating the printed conductive pattern, wherein the line width of the conductive pattern is set to 30 μm or less, and the thickness is set to 1 μm or more.

In this case, it is preferable that the pitch of the said conductive pattern is set to 400 micrometers or less.

As described above, in the present invention, using a conductive ink or conductive paste containing metal nanoparticles as the conductive pattern forming material, the line width and thickness of the conductive pattern printed on the transparent substrate by a noncontact or contact printing method are appropriately controlled. As a result, a transparent conductive film that satisfies the transparency and conductivity requirements can be formed.

In the present invention, after the conductive pattern is printed, it can be sintered by a batch treatment method. As a result of eliminating the conventional patterning process, the manufacturing process is very simple and the emission of pollutants can be minimized. Can be minimized and can be manufactured at low cost.

Also, in the present invention, the conductive film can be used for LCD, touch screen (touch panel), inorganic EL device, organic EL device, solar cell electrode and wiring.

1 is a cross-sectional view showing a transparent conductive film having a conductive pattern according to an embodiment of the present invention.

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

Referring to FIG. 1, the transparent conductive film 1 according to the exemplary embodiment of the present invention has, for example, a plurality of conductive patterns 12 arranged at intervals.

However, the present invention is used to form any shape of wiring and electrodes for pixels such as displays, touch screens, and the like, and is not limited to any particular shape.

The transparent conductive film according to the present invention can be used in LCDs, touch screens (touch panels), inorganic EL devices, organic EL devices, solar cells, wirings, and the like.

The transparent conductive film 1 includes a substrate 10 made of a transparent polymer film or transparent glass and at least one conductive pattern 12 formed on the transparent film substrate 10. An opening 14 is disposed between the conductive patterns 12.

The transparent substrate 10 may use a variety of substrates that can easily form a thin film or pattern through a printing process. The transparent substrate 10 is, for example, polyethylene terephthalate (PET), polyethernaphthalate (PEN), polyether sulfone (PES), nylon (Nylon), polytetrafluoroethylene (PTFE), polyether ether Transparent plastic films such as ketones (PEEK), polycarbonates (PCs), polyarylates (PARs), or glass substrates can be used.

The conductive pattern 12 may be formed on the transparent substrate 10 by using a non-contact printing method such as inkjet printing using a conductive ink containing metal nanoparticles, or by using a conductive paste containing metal nanoparticles. Contact printing methods such as printing, gravure printing, offset printing, pad printing can be used.

At this time, when the conductive pattern 12 is formed by the inkjet printing method, the laminated thickness of the printed ink is determined by the size of the opening of the nozzle, the opening / closing degree of the valve, the viscosity of the conductive ink, the traveling speed of the print head, and the like. By appropriately controlling these elements, the conductive pattern 12 of desired thickness and line width (size) can be formed.

In addition, when using a contact printing method such as screen printing, the conductive pattern 12 may be formed by using a screen having a slot having a desired pattern and a conductive paste having a high viscosity.

When the conductive pattern is formed by the screen printing method, a fine recess structure having a desired width and height corresponding to the shape of the conductive pattern is formed on the transparent substrate 10 using photoresist PR, and a conductive paste is applied to the photoresist recess. It is also possible to form the conductive pattern 12 having a desired structure by filling, sintering and removing the photoresist.

In addition, in the present invention, a seed layer may be primarily formed by filling a conductive paste in a part of the photoresist groove, and a conductive film may be formed by electroless plating or electrolytic plating using the seed layer.

In this case, the line width w of the conductive pattern 12 is preferably set to 30 μm or less, which is not recognized by the human eye. When the line width is too narrow, there is a limit in implementing a desired conductivity. ), The line width w depends on the thickness d of the conductive pattern 12.

In addition, the thickness d of the conductive pattern 12 is preferably set in the range of 1 to 30 μm in consideration of conductivity. When the thickness of the conductive pattern 12 is less than 1 μm, it is difficult to realize the desired conductivity at the line width w, and the thicker the thickness of the conductive pattern 12 is, the easier it is to implement the required conductivity, but the process time is longer. There is a problem that the cost rises and the manufacturing cost is limited to 30㎛ that can satisfy the required conductivity.

The line width and thickness of the conductive pattern 12 may vary depending on the printing method used to form the conductive pattern and the characteristics of the paste. In this case, the conductive pattern 12, i.e., a method of increasing the thickness d instead of reducing the line width w within this range while maintaining a constant volume (width * height) of the electrode to maintain a constant resistivity of the conductor. Can be changed.

Therefore, if the line width is reduced to the minimum and the height is increased to the maximum, even if the pitch between adjacent conductive patterns is set to 300 to 400 µm or less, the resistivity of the conductor can be secured while securing a desired aperture ratio, that is, transmittance.

In addition, the thickness of the conductive pattern 12 may be set to have an appropriate specific resistance in consideration of the current value flowing through the conductive pattern 12.

In addition, it is preferable that the pitch between the conductive patterns 12 is set to 400 μm or less in consideration of transparency (transmittance).

The conductive pattern 12 printed on the transparent substrate 10 with a conductive ink or a conductive paste is heat treated to impart conductivity. In general, the higher the heat treatment temperature is, the lower the specific resistance of the conductive pattern is.

That is, heat treatment is performed to remove the solvent component in the printed conductive pattern 12 and to sinter the nano metal powder. The heat treatment is usually performed by heating or irradiating light, wherein the amount of heat or light applied is determined by the sintering characteristics of the nano ink and paste in the conductive pattern 12 and the thickness of the printed conductive pattern 12. By the heat treatment, the conductive pattern 12 is deposited on the substrate 10 with the solvent component removed.

The heat treatment temperature depends on the substrate 10 used, and is usually set between 80 to 400 ° C. For example, when the substrate is glass, it is possible to heat-treat at a high temperature up to 300-400 ° C, and in the case of polyethylene terephthalate (PET), heat-treatment is required at 150 ° C or less. The heat treatment time is changed depending on the heat treatment temperature.

In addition, in the case of polymethylmethacrylate (PMMA) used in touch screens, touch modules, RFID, and flexible PCB (FPCB), low-temperature sintering is required at 150 ° C or lower.

In order to perform the heat treatment at 150 ° C. or lower, printing is performed using conductive metal nanoparticle ink or paste capable of low temperature sintering at 150 ° C.

The conductive metal nanoparticle ink or paste may be made of any one or two or more alloys selected from the group consisting of, for example, Ag, Pt, Au, Mg, Al, Zn, Fe, Cu, Ni and Pd. . The metal nanoparticles are preferably silver (Ag) nanoparticles in consideration of the material cost and electrical conductivity and the degree of oxidation.

As described above, in the present invention, the width of the conductive pattern 12 formed on the transparent substrate 10 is set to 30 µm or less invisible, and the thickness is set to 1 µm or more to use a non-transparent material. Even when formed, it is possible to have the desired transparency (transmittance) and conductivity.

Further, in the present invention, it is possible to realize a transparent conductive film for a display or a touch screen without removing a patterning process without using an expensive material such as ITO.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. Various changes and modifications may be made by those skilled in the art.

The transparent conductive film of the present invention and the method of manufacturing the transparent conductive film which satisfies the transparency and conductivity requirements by setting the line width and thickness of the conductive pattern in an appropriate range even if a non-transparent low cost material is used is a very simple and inexpensive manufacturing process. It can be used for the preparation of the membrane.

1: transparent conductive film 10: transparent substrate
12: conductive pattern 14: opening

Claims

Transparent substrate; And
Conductive patterns formed by adjusting the line width and thickness of the pattern by a non-contact or contact printing method using a conductive ink or a conductive paste on the transparent substrate,
The line width of the said conductive pattern is set to 30 micrometers or less, and the transparent conductive film is set to 1 micrometer or more in thickness.

The method of claim 1,
The conductive ink or conductive paste is transparent including metal nanoparticles made of any one or two or more alloys selected from the group consisting of Ag, Pt, Au, Mg, Al, Zn, Fe, Cu, Ni, and Pd. Conductive film.

Forming a conductive pattern on the transparent substrate by a non-contact or contact printing method using a conductive ink or a conductive paste; And
And heat treating the printed conductive pattern,
The line width of the said conductive pattern is set to 30 micrometers or less, and the manufacturing method of the transparent conductive film whose thickness is set to 1 micrometer or more.

The method of claim 3,
The pitch of the said conductive pattern is a manufacturing method of the transparent conductive film set to 400 micrometers or less.

The method of claim 3,
The transparent substrate is a method for producing a transparent conductive film made of a transparent polymer film or transparent glass.