KR20070051031A - Electronic paper display device having multi-layer electrode and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electronic paper display device having a multilayer electrode and a method for manufacturing the same, and in particular, a lower substrate and an upper substrate disposed to face each other at a predetermined interval; A lower electrode and an upper electrode inscribed to the lower substrate and the upper substrate, respectively, to form a pixel space; And particles encapsulated in a pixel space formed between the lower electrode and the upper electrode. The electronic paper display device of the present invention includes at least one of the lower electrode and the upper electrode including a silver (Ag) electrode layer and an indium tin oxide (ITO). The electrode layer has a multilayer electrode in which alternating layers are stacked, and in this case, an electrode having high transparency and a small surface resistance of 10 μs / square or less can be manufactured, which is particularly useful for an electronic paper display device having a large area of 40 inches or more. .

Electronic paper display device, silver electrode, multilayer electrode

Description

Electronic paper display device having a multi-layer electrode and a manufacturing method thereof {Electronic Paper Display Apparatus Having Multi-Electrode and Manufacturing Process Thereof}

1 is a cross-sectional view showing a cell structure of an electronic paper display device according to the prior art,

2 is a cross-sectional view and a perspective view showing a step of forming an electrode on the substrate of the electronic paper display device according to the prior art,

3 is a cross-sectional view illustrating an electronic paper display device having a multilayer electrode according to an embodiment of the present invention.

4 to 7 are flowcharts illustrating a method of manufacturing an electronic paper display device according to an embodiment of the present invention.

** Description of Symbols for Main Parts of Drawings **

1: Substrate 2: Lower ITO Electrode

3: silver (Ag) electrode 4: upper ITO electrode

5: multilayer electrode 6: photoresist

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic paper, and more particularly, to an electronic paper display device having a multilayer electrode and a manufacturing method thereof. More specifically, at least one of the lower electrode and the upper electrode which are inscribed to the lower substrate and the upper substrate which are disposed to face each other at predetermined intervals to form a pixel space, the silver electrode layer and the indium tin oxide (ITO) electrode layer may be formed. It is characterized in that the multi-layer electrode alternately stacked.

Due to the need for a transformation into a way of communicating and sharing information that corresponds to the information society that requires a new paradigm today, the development of electronic paper technology, which has the advantage of being able to bend as a flexible display, is entering the commercial development stage. . Electronic paper is a flexible display device that can display text or images by millions of beads scattered between flexible substrates such as thin plastics, and can be used to reproduce millions of times. It is expected to be a material to replace the print media.

The technical approach for implementing such a flexible display device is a method using a liquid crystal, an organic EL, a reflective film reflective display, a twisted ball, a mechanical reflective display, etc., in addition to the electrophoretic phenomenon. Most notable are display display devices using an electrophoretic phenomenon. It is based on electrophoresis, which applies electromagnetic fields to conductive materials to make it moveable. It distributes conductive particles between thin flexible substrates and then collides the particles by changing the polarity of the electromagnetic field. The data is represented by a change in the arrangement of the charged particles in the direction of the arrow.

The cell structure of the collision charged electronic paper display device is shown in FIG. 1 and briefly described as follows. As shown, the structure includes upper and lower substrates 70 and 10 formed of plastic or glass, and upper and lower electrodes formed of transparent electrode ITO to apply a driving voltage of the device on the upper and lower substrates. 80 and 20, upper and lower insulating layers 90 and 30 selectively coated on the upper and lower electrodes, a partition wall 40 separating the cell and the cell, and a white tablet formed between the two electrodes. It consists of the positive charged particle 50 and the black negative charged particle 60. In addition, although the upper and lower insulating layers 90 and 30 are omitted, there is no problem in driving, but it is preferable that the upper and lower insulating layers 90 and 30 are selected to reduce the movement of the charged particles attached to the electrode.

In the electronic paper display device having the above structure, when sufficient voltage is applied to the upper electrode 80 and the lower electrode 20, charged particles 50 and 60 charged according to the applied electrode polarity are attracted to each electrode. . For example, when-voltage is applied to the upper electrode 80 and + voltage is applied to the lower electrode 20, the white charged particles 50 positively charged by the coulomb force move toward the upper substrate 70. The charged black charged particles 60 move toward the lower substrate 10. Since the white charged particles 50 are located on the upper substrate 70 side, the white charged particles 50 appear to be white when viewed from the outside. On the contrary, when + voltage is applied to the upper electrode 80 and-voltage is applied to the lower electrode 20, the negatively charged black charged particles 60 move toward the upper substrate 70, and the positively charged white charged particles ( 50 is moved toward the lower substrate 10 to be displayed in black. Therefore, after applying a voltage so that all the cells appear white at first, only the desired cell is applied with the opposite voltage so that the cells appear black.

In order to manufacture the electronic paper display device according to the related art, first, a lower substrate 10 and an upper substrate (not shown) which are arranged to be disposed at predetermined intervals are prepared. Figure 2 is a cross-sectional view and perspective view showing a substrate manufacturing step of the electronic paper display device according to the prior art, the substrate disclosed herein can also be used as the lower substrate 10 or the upper substrate.

After the lower substrate 10 is prepared, as shown in FIG. 2, the lower electrode 20 is formed on the lower substrate 10, and the upper electrode is formed below the upper substrate. Since the basic electrode structure of a conventional general electronic paper display device is a matrix structure, the lower electrode 20 has a shape as shown in the right side of FIG. In addition, since the lower electrode 20 is for displaying an image of a pixel space in the display device, the lower electrode 20 or the upper electrode is generally transparent.

In addition, the lower electrode 20 and the upper electrode are for applying a driving voltage to the pixel space, and should be made of a conductive material. The transparent lower electrode 20 is generally an ITO electrode. The formation of the upper electrode on the upper substrate is the same as the method of forming the lower electrode 20 on the lower substrate 10. Here, the method of forming the lower electrode 20 on the lower substrate 10 will be described. And description of the upper electrode.

The conventional electronic paper display device manufactured according to the above method is a reflective display device that displays an image by moving particles in the pixel space. For this purpose, the lower electrode and the upper electrode are used for the movement of the particles in the pixel space. Since light must be projected, at least one of the lower electrode and the upper electrode used as the display unit must be transparent.

In addition, since the image is formed by the mutual movement of the charged particles by the voltage applied to the lower electrode and the upper electrode, the lower electrode and the upper electrode should be made of a conductive material. As described above, a transparent and conductive electrode material, conventionally a conductive polymer such as polythiopin or polyaniline, a printed conductor such as a polymer film containing metal particles such as silver or nickel, graphite or conductive carbon material, Or printed conductors such as polymer films containing conductive oxides such as tin oxide or indium tin oxide. Most commonly, indium tin oxide (ITO) is used to form electrodes by deposition or coating or printing.

However, when the ITO electrode is applied to a flexible electronic paper display device, there is a problem in that fine cracks occur due to repeated bending, and thus short-circuit of the electrode occurs, resulting in a serious decrease in product quality and lifespan. The problem appeared. In addition, when the ITO electrode is applied to a large display device of 40 inches or more, there is a serious problem in that the surface resistance (100 kPa / square to 500 kPa / square) of the ITO electrode is much higher than the reference requirement (10 kPa / square or less) and thus the transmittance is poor. Therefore, in addition to the conventional ITO electrode, it is urgent to develop an electrode material having excellent elasticity even in a flexible display device and high transmittance even in a large display.

The present invention has been made to solve the above problems, in the electronic paper, a new type of electronic paper display device and a manufacturing method of the multi-layer structure in which the electrode formed on the substrate comprises a silver (Ag) electrode It is to provide. Particularly, according to the present invention, at least one of the lower electrode and the upper electrode which are internally in contact with the lower substrate and the upper substrate disposed at predetermined intervals to form a pixel space is a multilayer in which a silver electrode layer and an ITO electrode layer are alternately stacked. An object of the present invention is to provide an electronic paper display device, which is an electrode.

By manufacturing the electronic paper display device having a multi-layer electrode according to the present invention, it is to solve the problem of the occurrence of small cracks and high surface resistance by indium tin oxide (ITO) electrode as in the prior art. That is, according to the present invention, a multilayer electrode having a silver electrode layer and an ITO electrode layer alternately stacked is intended to produce an electrode having a high transmittance and a small surface resistance of 10 kW / square or less. In particular, by applying the electrode having a high transmittance and low surface resistance to a large display device of 40 inches or more, it is to provide an electronic paper display device that can obtain excellent image quality with high transmittance.

In addition, by using an electrode having a multi-layered structure in which silver electrodes and ITO electrodes are alternately stacked, defects such as pinholes generated in conventional indium tin oxide (ITO) electrodes and the like can be filled, and fineness due to bending of the flexible substrate can be achieved. An object of the present invention is to provide an electronic paper display device capable of suppressing the occurrence of cracks or radio waves.

The present invention for achieving this object is the lower substrate and the upper substrate which is disposed facing at a predetermined interval; A lower electrode and an upper electrode inscribed to the lower substrate and the upper substrate, respectively, to form a pixel space; And particles encapsulated in a pixel space formed between the lower electrode and the upper electrode, wherein at least one of the lower electrode and the upper electrode is a multilayer in which an silver (Ag) electrode layer and an indium tin oxide (ITO) electrode layer are alternately stacked. An electronic paper display device having an electrode.

Here, the partition wall for dividing the pixel space between the lower electrode and the upper electrode may be further included, wherein the multilayer electrode, that is, the silver electrode layer and the ITO electrode layer is alternately stacked, the silver metal layer is stacked on the ITO electrode layer, the silver metal layer It is preferable that an ITO electrode layer be laminated on it, and such a multilayer electrode is more preferably a three-layer film.

In the present invention having a multilayer electrode in which a silver electrode layer and an ITO electrode layer are alternately stacked, the thickness of the silver electrode layer may be in the range of 10 nm to 20 nm, and the thickness of the ITO electrode layer is in the range of 40 nm to 50 nm. The thickness of the multilayer electrode may be in the range of 100nm to 150nm.

In addition, in the electronic paper display apparatus having a multilayer electrode according to the present invention, it is preferable that the multilayer electrode has a surface resistance within a range of 1 Ω / □ to 10 Ω / □, wherein the multilayer electrode is 85% to 95 at a wavelength of 550 nm. It is more preferable to have a transparency in the range of%, and the present invention is an electronic paper display device having a multilayer electrode which is most preferably applied to a display device having a large area of 40 inches or more.

In addition, the present invention may be characterized in that it further comprises a lower insulating layer and an upper insulating layer inscribed in the lower electrode and the upper electrode, respectively, the particles enclosed in the pixel space formed between the lower electrode and the upper electrode Electronic paper display devices having multilayer electrodes characterized in that the chargeable or charged dry particles are also possible.

Another embodiment of the present invention for achieving the above object relates to a method for manufacturing an electronic paper display device having a multilayer electrode as described above. Specifically, forming a multilayer electrode by sputtering the silver (Ag) electrode film and the indium tin oxide (ITO) electrode film alternately on the substrate; Patterning a photoresist on a portion of the region where the electrode on the multilayer electrode is to be formed; Etching the multi-layer electrode on which the photoresist is not patterned; And removing the photoresist; and a method of manufacturing an electronic paper display device having a multilayer electrode to form an electrode.

The forming of the multi-layer electrode may include forming a multi-layered electrode having a three-layer stacked structure by sputtering a silver metal film on the ITO electrode film and sputtering the ITO electrode film on the silver metal film. A method of manufacturing an electronic paper display device is also possible.

Hereinafter, one preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

In the electronic paper display device having a multilayer electrode according to the present invention, at least one of the lower electrode and the upper electrode which are internally inscribed on the lower substrate and the upper substrate to form a pixel space is a multilayer electrode in which silver electrode layers and ITO electrode layers are alternately stacked. It characterized in that, the lower substrate and the upper substrate which is arranged facing at a predetermined interval; A lower electrode and an upper electrode inscribed to the lower substrate and the upper substrate, respectively, to form a pixel space; And particles encapsulated in the pixel space formed between the lower electrode and the upper electrode may be the same as the components of the electronic paper that can be commonly used in the art to which the present invention pertains. Such a lower substrate and an upper substrate; A lower electrode and an upper electrode; And particles may exemplify those described in the prior art.

If the electronic species having such a structure, it may be characterized in that it further comprises a partition wall partitioning the pixel space between the lower electrode and the upper electrode. Electronic paper generally has a form in which the pixel space is divided into a plurality of cells by a partition between the lower electrode and the upper electrode, but the electronic paper using some microcapsules may be imaged by the movement of black or white particles. Therefore, the electronic paper display device to which the present invention can be applied can be applied not only to electronic paper not including a partition, but also to electronic paper having a partition. This is because the upper electrode or the lower electrode is a multilayer electrode in which a silver electrode layer and an ITO electrode layer are alternately stacked.

Then, in detail with respect to the multilayer electrode in which the silver electrode layer and the ITO electrode layer is alternately stacked according to the present invention as follows. The multilayer electrode according to the present invention may correspond to a lower electrode or an upper electrode, and both the lower electrode and the upper electrode may be formed of the multilayer electrode according to the present invention.

The multilayer electrode used in the present invention has a structure in which a silver electrode layer and an ITO electrode layer are alternately stacked. Here, the ITO electrode layer is stacked on the alternately stacked silver electrode layer, and the silver electrode layer is stacked on the ITO electrode layer. More preferably, the form of the stack is 'alternatively' laminated, the multi-layer electrode according to the invention is a form in which the ITO electrode layer is laminated on both sides with the silver electrode layer between or the silver on both sides with the ITO electrode layer between The form in which the electrode layers are stacked is suitable. As long as it is laminated | stacked alternately like this, there is no restriction | limiting in particular in the laminated | stacked frequency and height.

The present invention is characterized by having a multi-layered electrode in which a silver electrode layer and an ITO electrode layer are alternately stacked. According to the electronic paper display device having a multilayer electrode according to the present invention, it is possible to produce an electrode having a high transparency and a small surface resistance of 10 kW / square or less. The conventional ITO electrode has a thickness of 50 nm to 500 nm, and has a surface resistance of about 100 μs / □ to 500 μs / □, which causes a problem of poor transmittance in a large display of 40 inches or more requiring a surface resistance of 10 μs / □ or less. However, according to the present invention, the multilayer electrode in which the silver electrode and the ITO electrode are alternately laminated is particularly useful for electronic paper display devices having a large area of 40 inches or more because of low surface resistance.

When a silver (Ag) metal thin film is used in the form of a single layer as an electrode of an electronic paper, an electrode having a very low specific resistance can be produced. However, when the thickness of the silver metal thin film is 50 nm or less, it is difficult to grow into a continuous film, and the scattering phenomenon of incident light increases, so that the transmittance is remarkably decreased. Therefore, it is not suitable to use only a silver metal thin film as an electrode of an electronic paper, and in the present invention, in order to compensate for this, a multi-layered structure in which a silver metal thin film and an ITO electrode are alternately stacked through a multilayer electrode structure while maintaining a low resistance to be a continuous film It is proposed.

In the present invention, the silver electrode layer and the ITO electrode layer is alternately stacked, as shown in Figure 3, the silver metal (3) layer is laminated on the lower ITO electrode (2) layer, the silver metal (3) layer It is preferable that the upper ITO electrode 4 layer is stacked thereon. 3 is a cross-sectional view illustrating an electronic paper display device having a multilayer electrode according to an embodiment of the present invention. That is, as shown here, the multi-layer electrode 5 according to the present invention is located on the substrate 1, the multi-layer electrode 5 having a silver metal 3 layer in the center and below the silver metal 3 layer. A structure in which the lower ITO electrode 2 layer is located and the upper ITO electrode 4 layer is stacked on the silver metal 3 layer is suitable.

The reason why the structure of the multilayer electrode 5 in which the silver metal 3 is inserted between the upper and lower ITO electrodes 2 and 4 is suitable is to insert the silver metal 3 layer having a low resistance in the center. In order to make the multilayer electrode 5 according to the present invention have a low resistance size, the surface of the silver metal 3 layer is difficult to grow into a continuous film and light transmittance is reduced to compensate for this. The ITO electrodes 2 and 4 layers which are possible and excellent in transparency are arranged on both sides of the silver metal 3 layer.

Since the present invention has a laminated structure of three layers, there is an effect that it is possible to fill up defects such as pinholes that are common in conventional ITO monolayer electrodes. Herein, the pinhole refers to a very small hole or a gap of several nm to several μm. When an electrode (metal) is formed in a state where there are many pinholes, a short occurs in the metal through the hole. In order to avoid this, conventionally, the film thickness had to be made thicker than predetermined. However, the thicker the film, the higher the voltage must be, so the current does not flow well. Moreover, until now, even at high voltages of tens of volts and hundreds of volts, the film thickness has hindered almost no light.

Accordingly, in the present invention, through the multilayer electrode structure in which the silver metal layer and the ITO electrode layer are alternately stacked, in particular, the multilayer electrode structure in which the ITO electrode layer is disposed on both sides of the silver metal layer, such defects such as pinholes can be easily solved. There is an effect that can suppress the occurrence of microcracks and radio waves due to bending.

As described above, the present invention is characterized by a multilayer electrode in which a silver metal layer and an ITO electrode layer are alternately stacked, and this multilayer electrode ultimately becomes an electrode that serves to apply a voltage to the pixel space of the electronic paper. In such a flexible display device, the thinner the electrode, the thinner the ultra-lightweight super-integration can be achieved, and even if the flexible substrate is bent, the gap may not be widened or cracked. Accordingly, the multilayer electrode structure according to the present invention may be a three-layer film structure in which silver electrode layers are stacked on both sides of the ITO electrode layer, and a three-layer film structure in which the ITO electrode layers are stacked on both sides of the silver electrode layer is more preferable.

To this end, the thickness of the silver electrode layer may be in the range of 10nm to 20nm, the thickness of the ITO electrode layer may be in the range of 40nm to 50nm. This is because when the thickness of the silver electrode layer is 10 nm or less, the low resistance effect of the silver electrode layer cannot be properly utilized, and when the thickness of the silver electrode layer is 20 nm or more, there is a problem in that the transmittance is poor due to the particle film characteristics. In addition, when the thickness of the ITO electrode layer is 40nm or less, it is difficult to produce a continuous film, and when the thickness of the ITO electrode layer is 50nm or more, there is a problem of poor transmittance.

Accordingly, the thickness of the multilayer electrode in which the silver metal layer and the ITO electrode layer are alternately stacked may be within a range of 100 nm to 150 nm. The lower electrode and the upper electrode having such a multi-layered electrode structure may be more preferably selected from transparent electrodes, and when bent, the strain does not change even when the strain is about 1.5%, and the adhesion force with the substrate is 100 nm to 150 nm. It is desirable to have a thickness.

As described above, the multilayer electrode according to the present invention may be a transparent electrode having a low surface resistance because a silver electrode layer having a low resistance size and an ITO electrode layer having a high transmittance are alternately stacked and thinly coated. In addition, since the multilayer electrode structure according to the present invention has excellent elasticity, even when the electronic paper is applied to the display device, due to repeated bending, cracks do not occur and short-circuit phenomenon of the electrode does not occur. This is an excellent and durable effect.

Moreover, until now, the electrode which can be applied to the electronic paper of about A4 size should have sufficient surface resistance about 5000 kPa / square or less. Thus, conventionally, ITO was deposited on a substrate using a transparent electrode, or used in a thickness of 50 nm to 500 nm by spray coating or printing. At this time, the surface resistance of the electrode is about 100 kW / □ to 500 kW / □. However, this size of surface resistance has been limited in large screens larger than 40 inches. In order to apply to large wall papers larger than 40 inches, a low surface resistance of less than about 10 mW / □ was required.

Accordingly, the present inventors studied an electrode structure capable of maintaining a high transmittance while having a lower surface resistance, and by stacking the silver electrode layer and the ITO electrode layer alternately according to the present invention, it is possible to maintain low surface resistance and high transmittance. The electrode layer was developed. It has been confirmed that the surface resistance of the multilayer electrode according to the present invention is in the range of 1 kV / □ to 10 kV / □, and more preferably, the surface resistance of the multilayer electrode is as small as 4 kV / □.

The size of the surface resistance can be adjusted by varying the thickness of the silver electrode layer and the ITO electrode layer, the surface resistance is preferably at least 1Ω / □ or more for the skin effect to flow the current toward the skin of the lower electrode or the upper electrode. In addition, although the surface resistance may be 10 Ω / □ or more, it is more preferable to have a surface resistance of 10 Ω / □ or less in particular to be applied to a display having a large area of 40 inches or more.

Accordingly, the multilayer electrode according to the present invention can have a surface resistance of 10 kW / square or less, and in this case, high transmittance can be maintained even in a large display device of 40 inches or more. The multilayer electrode according to the present invention, in particular the three-layer transparent electrode is applicable to both the upper and lower plates of the electronic paper, it was confirmed that exhibits a transparency of 85% to 95%, more specifically about 90% at 550nm wavelength, It is almost the same value as the transmittance of the single-layer ITO transparent electrode.

Subsequently, a lower insulating layer or an upper insulating layer may be further formed on the lower electrode or the upper electrode according to the present invention. That is, the electronic paper display device having a multilayer electrode according to the present invention may further comprise a lower insulating layer and an upper insulating layer inscribed in the lower electrode and the upper electrode, respectively.

The lower insulating layer or the upper insulating layer may be formed to prevent electrophoretic particles from adhering to the electrode and being discharged. Although the lower insulating layer or the upper insulating layer applied on the lower electrode or the upper electrode is omitted, there is no problem in driving. However, when the charged particles are in close contact with the electrode and the electron movement occurs, the memory effect is reduced and the image is applied without applying new power. It may be difficult to preserve for a long time, so it is preferable to apply.

In the formation of such an insulating layer, it is formed to a thickness of 0.01 µm to 10 µm by a method such as sputtering, chemical vapor deposition (CVD), or vacuum deposition. The material is preferably a transparent material, and silicon oxide, silicon nitride, silicon carbide, aluminum oxide, tantalum oxide (Ta ₂ O ₃ ), and the like may be selected, and a polymer resin may be selected.

Meanwhile, particles for expressing an image are injected into the pixel space formed between the lower electrode and the upper electrode, and the particles may be charged or charged dry particles.

In the electronic paper display device according to the present invention, the particles are used for image expression, and any electrophoretic particles used for image expression in the technical field of the present invention may be used. Among these, dry particles may be preferably selected. Electrophoretic particles having different colors and charging characteristics are selected, and in order to display monochrome, it is preferable to use carbon black as black particles and titanium oxide as white particles. The charged particles may be injected, or may be applied while charging by using a corona discharge at the time of coating.

As described above, the present invention provides a flexible electronic paper display device, in which an electric field is imparted to the particles by a lower electrode and an upper electrode made of a multilayer electrode, which can be applied to all electronic papers having electrodes. It is also applicable to wet electronic paper using a microcapsule without a partition wall. Preferably, after injecting uncharged particles, a voltage is applied to the upper and lower electrodes, and the particles collide with each other to generate a charge due to a collision. It is suitable for an electronic paper display device having a dry collision charging type electrophoretic particles to form electrophoretic particles.

Another preferred embodiment of the present invention for achieving another object of the present invention relates to a method for manufacturing an electronic paper display device having a multilayer electrode as described above.

Specifically, forming a multilayer electrode by sputtering the silver (Ag) electrode film and the indium tin oxide (ITO) electrode film alternately on the substrate; Patterning a photoresist on a portion of the region where the electrode on the multilayer electrode is to be formed; Etching the multi-layer electrode on which the photoresist is not patterned; And removing the photoresist; and a method of manufacturing an electronic paper display device having a multilayer electrode to form an electrode. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic paper. In particular, in an electronic paper display device, a method of manufacturing a multilayer electrode in which a silver electrode layer and an ITO electrode layer are alternately stacked is provided.

In the present invention, the method of forming the multilayer electrode is preferably a photolithography method using a photoresist. In addition, an inkjet printing method, a method using a photosensitive polymer, a laminating method using a cut of a pre-made material, and the like are possible. Hereinafter, a photolithography method using a photoresist will be described in detail with reference to FIGS. 4 to 7.

First, as shown in FIG. 4, the multilayer electrode 5 is formed by alternately sputtering the silver (Ag) electrode 3 film and the indium tin oxide (ITO) electrode 2, 4 film on the substrate 1. Go through the steps The substrate 1 may also be used as a lower substrate or an upper substrate of the electronic paper display device. The lower substrate and the upper substrate are preferably made of a flexible material. Flexible materials of the general glass substrate or flexible plastic type can be selected. Preferably, it may be selected from polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone (PES) or polyimide film (Kapton, Upilex), but is not limited thereto. It is most preferable that the thickness of the substrate 1 be about 0.05 mm to 0.5 mm in order to realize a thin film while giving a predetermined strength.

In the forming of the multilayer electrode 5, the silver metal 3 film is sputtered on the lower ITO electrode 2 film, and the upper ITO electrode film 4 is sputtered on the silver metal 3 film. It is also possible to form a multilayer electrode 5 having a stacked structure of. The present invention is characterized by a three-layer film electrode having an ITO electrode (2, 4) layer disposed on both sides of the silver electrode (3) layer in the center of the silver electrode (3) layer, the lower ITO electrode (2) film on the substrate It is preferable to sequentially stack the silver metal 3 film and the upper ITO electrode 4 film.

Here, as the method for laminating the silver electrode 3 film and the ITO electrode 2, 4 film, it is most preferable to sputtering, in particular, to sputter and stack in a vacuum continuously. It is also possible to stack the silver electrode 3 film or the ITO electrode 2, 4 film by this.

Next, as shown in FIG. 5, the photoresist 6 is patterned on a part of the region where the electrode on the multilayer electrode 5 is to be formed. Patterning the photoresist 6 allows the photoresist 6 to be coated only on the desired portion where the electrode is to be formed using a photomask or the like. Here, the photoresist 6 to be used is applied only to a part of the area where the electrode is to be formed, and later, only the part of the area is left and other areas are etched and removed. The photoresist 6 has a negative form and a passive form, and the fact that it can be freely selected to form an electrode as required is obvious to those skilled in the art. After coating the photoresist 6 is subjected to an exposure and development process.

Subsequently, as shown in FIG. 6, the photoresist 6 is subjected to the etching of the multilayer electrode 5 in the unpatterned region. The etching method is not particularly limited, and a dry etching method or a wet etching method may be used, and more preferably, wet etching is possible. Through the etching process, an electrode having a desired size can be formed from the multilayer electrode 5 thin film material.

Finally, as shown in FIG. 7, the step of removing the photoresist 6 is performed. That is, after etching the region to which the photoresist 6 is not applied as described above, the photoresist 6 which is not exposed to the electrode formation site is removed. By going through such a step, according to the present invention, an electrode having a multi-layer electrode 5 structure in which the silver electrode 3 layer and the ITO electrode layers 2 and 4 are alternately stacked can be completed.

In addition, after removing the photoresist 6, the electronic paper display device having the multilayer electrode 5 further comprising the step of cleaning and drying the substrate 1 on which the multilayer electrode 5 is formed. Manufacturing methods are also possible.

In the above description, it should be understood that those skilled in the present invention can only make modifications and changes to the present invention without changing the gist of the present invention as merely illustrative of a preferred embodiment of the present invention.

As described above, according to the present invention, a lower substrate and an upper substrate are disposed to face each other at a predetermined interval; A lower electrode and an upper electrode inscribed to the lower substrate and the upper substrate, respectively, to form a pixel space; And particles encapsulated in a pixel space formed between the lower electrode and the upper electrode, wherein at least one of the lower electrode and the upper electrode is a multilayer in which an silver (Ag) electrode layer and an indium tin oxide (ITO) electrode layer are alternately stacked. An electronic paper display device having an electrode can be provided.

According to the electronic paper display device having a multilayer electrode according to the present invention, it is possible to produce an electrode having a high transparency and a small surface resistance of 10 kW / square or less. The conventional ITO electrode has a thickness of 50 nm to 500 nm, and has a surface resistance of about 100 μs / □ to 500 μs / □, which causes a problem of poor transmittance in a large display of 40 inches or more requiring a surface resistance of 10 μs / □ or less. However, according to the present invention, in the case of the multilayer electrode in which the silver electrode and the ITO electrode are alternately stacked, the electronic paper having a large area of 40 inches or more can be usefully applied.

In addition, the multilayer electrode structure in which the silver electrode and the ITO electrode are alternately stacked may fill defects such as pinholes generated in the conventional indium tin oxide (ITO) electrode, and the like, and may be used for micro cracks due to bending of the flexible substrate. There is an effect that can suppress the occurrence of radio waves.

Claims (12)

A lower substrate and an upper substrate disposed to face each other at a predetermined interval; A lower electrode and an upper electrode inscribed to the lower substrate and the upper substrate, respectively, to form a pixel space; And Includes particles enclosed in the pixel space formed between the lower electrode and the upper electrode, And at least one of the lower electrode and the upper electrode has a multilayer electrode in which a silver (Ag) electrode layer and an indium tin oxide (ITO) electrode layer are alternately stacked. The electronic paper display apparatus of claim 1, further comprising a partition wall partitioning the pixel space between the lower electrode and the upper electrode. The electronic paper display apparatus according to claim 1, wherein the multilayer electrode has a silver metal layer stacked on the ITO electrode layer, and an ITO electrode layer stacked on the silver metal layer. The electronic paper display apparatus of claim 1, wherein the silver electrode layer has a thickness in a range of 10 nm to 20 nm. The electronic paper display apparatus of claim 1, wherein the thickness of the ITO electrode layer is in a range of 40 nm to 50 nm. The electronic paper display apparatus of claim 1, wherein the multilayer electrode has a thickness in a range of 100 nm to 150 nm. The electronic paper display apparatus of claim 1, wherein the multilayer electrode has a surface resistance within a range of 1 μs / □ to 10 μs / □. The electronic paper display apparatus of claim 1, wherein the multilayer electrode has a transparency within a range of 85% to 95% at a wavelength of 550 nm. The electronic paper display apparatus of claim 1, further comprising a lower insulating layer and an upper insulating layer inscribed to the lower electrode and the upper electrode, respectively. The electronic paper display device of claim 1, wherein the particles are chargeable or charged dry particles. Forming a multilayer electrode by alternately sputtering a silver (Ag) electrode film and an indium tin oxide (ITO) electrode film on a substrate; Patterning a photoresist on a portion of the region where the electrode on the multilayer electrode is to be formed; Etching the multi-layer electrode on which the photoresist is not patterned; And Removing the photoresist; and a method of manufacturing an electronic paper display device having a multi-layer electrode including electrodes. 12. The method of claim 11, wherein the forming of the multi-layer electrode comprises: sputtering a silver metal film on the ITO electrode film and sputtering the ITO electrode film on the silver metal film to form a multi-layer electrode having a three-layer stack structure. A method of manufacturing an electronic paper display device having a multilayer electrode.

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