KR100667497B1 - Electrical Paper Display Having The Third Electrode and Manufacturing Method Thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic paper display device having a three-pole structure and a method of manufacturing the same. In particular, an electronic paper display having a three-pole structure capable of moving charged particles to a low driving voltage by forming a third electrode separately from the counter electrode is provided. An element and a method of manufacturing the same. This configuration solves the problem of applying the high resolution of the conventional three-pole structure, and it is possible to implement the image even at a low voltage to obtain a high contrast ratio with low power consumption and to remove cross-talk between pixels. To provide.

Electronic paper, 3-pole structure, third electrode

Description

Electronic paper display device having a three-pole structure and a manufacturing method thereof {Electrical Paper Display Having The Third Electrode and Manufacturing Method Thereof}

1 is a cross-sectional view of an electronic paper display device using a conventional electrophoresis phenomenon,

2 is a cross-sectional view of a dry electronic paper display element;

3 is a cross-sectional view of a conventional three-pole electronic paper display device;

4 is a cross-sectional view of an electronic paper display device having a three-pole structure according to an embodiment of the present invention;

5 is a cross-sectional view of an electronic paper display device having a three-pole structure according to another embodiment of the present invention;

6 is a diagram of electric field analysis of one pixel of a conventional electronic paper display element;

7 is a diagram illustrating an electric field analysis of one pixel of the electronic paper display device of the present invention.

※ Explanation of the main symbols in the drawing

10: lower substrate 20: upper substrate

11: data electrode 21: scan electrode 16a, 16b: third electrode

12a, b: charged particles 13: pixel space 14: partition wall

15: insulation layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus involving movement of particles using electrophoresis, and particularly, to form a third electrode separately from the counter electrode, to display a three-pole structure of electronic paper capable of moving charged particles at a low driving voltage. An element and a method of manufacturing the same.

In recent years, with the spread of the network, documents distributed in the form of conventional printed matter have been replaced by so-called electronic documents. Moreover, books and magazines are often provided in the form of so-called electronic publishing.

In order to read these information, what is conventionally performed is reading from the CRT of a computer, a liquid crystal display, etc. However, it has been pointed out that such light emitting displays suffer from ergonomic reasons and cannot withstand long periods of reading. In addition, there is a difficulty in that the reading place is limited to an installation place such as a computer and an LCD.

In recent years, notebook computers can be used as portable displays because of the widespread use of notebook computers. However, due to the light emission type of the backlight, it cannot be used for reading for several hours or more due to power consumption problems. In recent years, reflective liquid crystal displays have also been developed, which can be driven with low power consumption. It is bad, and fatigue is easy to occur, and this also cannot endure long time reading.

In order to solve these problems, what is called the electronic paper is developed recently. Electronic paper is much cheaper to produce than conventional flat panel displays, and since it does not require background lighting or continuous recharging like a normal screen, it can be driven with very little energy, leading to energy efficiency. In addition, the electronic paper is very sharp, has a wide viewing angle, and has a memory function that does not completely disappear even in the absence of power.

This great advantage makes electronic paper a great candidate for a wide range of applications, such as e-books with paper-like sides and moving illustrations, self-renewable newspapers, reusable paper displays for mobile phones, disposable TV screens and electronic wallpaper. It has a huge potential market.

The technical approaches to electronic paper implementation include liquid crystal method, organic EL, reflective film reflective display, electrophoresis, twist ball, and mechanical reflective light. Electronic paper display device using the phenomenon.

Electrophoresis is a phenomenon in which when a particle is suspended in a medium (dispersion medium), the particles are electrically charged, and when an electric field is applied to the charged particles, they move through a dispersion medium to electrodes having opposite charges. A representative diagram of the electrophoretic display device using this phenomenon is shown in FIG. 1 and briefly described as follows.

As shown in FIG. 1, an electrophoretic display includes an upper substrate 101 and a lower substrate 102 positioned in a predetermined gap, and an insulating liquid 103 filled between the substrates 101 and 102. And a plurality of colored charged particles 104 dispersed in the insulating liquid 103 and upper and lower display electrodes 105 and 106 positioned in each pixel so as to be placed on the respective substrates 101 and 102. . A partition wall 107 is formed between the pixels to prevent the colored charged particles 104 from moving to other pixels.

1A and 1B are sectional views showing a single pixel, and the actual electrophoretic display device is constructed by arranging such a plurality of pixels. In such a device, since the colored charged particles 104 are charged with the positive electrode or the negative electrode, the upper display electrode 105 or the lower display electrode (depending on the polarity of the voltage applied to the upper and lower display electrodes 105 and 106). 106). On the other hand, the insulating liquid 103 and the colored charged particles 104 are colored in different colors, respectively. As a result, when the colored electrophoretic particles 104 are biased toward the upper display electrode 105 on the observer's side, the color of the particles 104 is observed (see FIG. 1B), and the colored electrophoretic particles 104 are observed. When the color is biased toward the lower display electrode 106, the color of the insulating liquid 103 is observed (see FIG. 1A). Therefore, various images can be displayed by controlling the polarity of the applied voltage for each pixel. The electrophoretic display device has advantages such as a wide viewing angle close to that of a normal printed matter, low power consumption, and a memory function.

However, there is a problem in that clustering and aggregation of ink fine particles due to dispersion instability over time are formed. In addition, the response speed is slow due to the viscous resistance of the liquid has a lot of problems in the video implementation. In addition, the viscous resistance of the liquid causes a high driving voltage.

As one of techniques for solving this problem, a dry electronic paper display device is illustrated in FIG. 2. As shown in FIG. 2, in the dry electronic paper display device, transparent substrates 111 and 112 having electrodes 114 and 115 formed in a pixel space region on one surface thereof are disposed to face each other, and are separated from each other by a partition wall 113. By enclosing two types of particle groups 86 of different dry, color and charging characteristics without liquid viscous characteristics and applying voltage to the electrodes 114 and 115 of the upper and lower plates, the particles collide with each other. An electric paper display element which displays an image by moving an electric field to a group of charged particles from two kinds of electrodes 114 and 115 having different electric potentials after forming a charged particle by applying a charge due to a collision.

Since the dry electronic paper device does not have a material having a high viscosity such as liquid in the pixel space, the response speed is considerably fast, and the driving voltage increase caused by the viscosity resistance of the liquid is solved. However, such a dry electronic paper device has a disadvantage of still requiring a high driving voltage and having a relatively high power consumption in order to obtain a high contrast ratio.

In order to overcome this disadvantage, as shown in FIG. As shown in FIG. 3, the electronic paper display device having a three-pole structure type is disposed on the upper and lower substrates 121 and 122 spaced apart from each other at predetermined intervals, the partition wall 123 dividing the pixels, and coated on the substrate. The upper and lower counter electrodes 124 are positioned in specific center regions of the top and bottom of the pixel, and are coated on the substrate, and are positioned at edges of the top and bottom of the pixel, respectively, and on both sides of the upper and lower electrodes 124. The third electrode 125 is positioned to be spaced apart by a predetermined distance in the direction, it is characterized by consisting of charged particles 126 encapsulated in the pixel space.

Through this three-pole structure, the driving voltage can be lowered more effectively and a high contrast ratio can be obtained.

However, the conventional three-pole structure has a problem that the size of the pixel is relatively large because the third electrode 125 is positioned in the pixel in the same layer as the upper or lower electrode 124, and the pixel size is larger than the two-pole structure. There is a limit that cannot be reduced, which makes it difficult to apply high resolution.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and realizes a high contrast ratio with a low driving voltage, and has a higher space utilization in the pixel and more effectively reduces the size of the pixel than a conventional three-pole electronic paper display element. An object of the present invention is to provide an electronic paper display device capable of achieving high resolution and a manufacturing method thereof.

In order to achieve the above object, the present invention derives an electronic paper display device using a three-pole structure in which the third electrode is positioned on a different layer from the other electrode.

That is, the present invention is in contact with the lower substrate 10 and the upper substrate 20, the third electrode (16a, 16b) and the third electrode which are inscribed in the lower substrate and the upper substrate, respectively, at predetermined intervals. Insulating the insulating film 15, the insulating film 15, and the data electrode 11, the scan electrode 21, and the pixels formed in the lower and upper portions of the pixel space 13, respectively, and the pixel space 13 is formed. The present invention provides a three-pole electronic paper display device including a plurality of partition walls 14 and a plurality of charged particles 12 enclosed in the pixel space 13.

In addition, the third electrode 16 provides an electronic paper display device having a three-pole structure, which is located on the entire upper and lower substrates.

In addition, the third electrode 16 is patterned in the same shape as the scan electrode 21 and the data electrode 11 to provide an electronic paper display device having a three-pole structure characterized in that located on the vertical extension line of the pixel space. do.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

4 is a cross-sectional view of an electronic paper display device having a three-pole structure according to an embodiment of the present invention.

That is, the third and second electrodes 16a and 16b in contact with the lower substrate 10 and the upper substrate 20, the lower and upper substrates, respectively disposed at predetermined intervals, and the insulating layer in contact with and insulate the third electrode. 15 and a plurality of data electrodes 11 and scan electrodes 21 formed in the lower and upper portions of the pixel space 13 and in the pixel in the pixel space 13. An electronic paper display device having a three-pole structure according to the present invention including a partition wall 14 and a plurality of charged particles 12 enclosed in the pixel space 13 is shown.

The configuration of the above-described three-pole electronic paper display device will be described in more detail.

The upper and lower substrates 10 and 20 are both made of a flexible material of a general glass substrate or flexible plastic type. Preferably, it may be selected from polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone (PES) or polyimide film (Kapton, Upilex), but is not limited thereto.

The thickness of the substrate is most preferably about 0.05 to 0.5 mm in order to achieve a thin film while giving a predetermined strength.

The upper and lower third electrodes 16a and 16b positioned on the substrates 10 and 20 are conductive materials, and electrode materials commonly used in the art of the present invention may be used, and polythiopine or polyaniline Printers such as printed conductors such as conductive polymers, such as polymer films containing metal particles such as silver or nickel, graphite or conductive carbon materials, or polymer films containing conductive oxides such as tin oxide or indium tin oxide Conductor may be included, and indium tin oxide (ITO) may be selected, and it is preferable to use a transparent electrode.

The third electrode 16 may be located on the entire surface of the upper and lower substrates. In this case, the manufacturing process is simple because it is located over the front of the substrate.

The data electrode 11 and the scan electrode 21 are positioned in contact with the insulating film 15, and are specifically positioned at the lower and upper portions of the pixel space, respectively.

The material used is a conductive material, any electrode material commonly used in the technical field of the present invention can be used, and conductive polymers such as polythiopine or polyaniline, polymer films containing metal particles such as silver or nickel, and the like. Printed conductors such as printed conductors, graphite or conductive carbon materials, or polymer films containing conductive oxides such as tin oxide or indium tin oxide, and the like, and indium tin oxide (ITO) may be selected. .

The scan electrode 21 is preferably a transparent electrode such as indium tin oxide (ITO) in order to increase light efficiency.

As the material of the partition wall 14 of the present invention, a flexible material is preferable, and a polymer such as polycarbonate (PC), polyethylene terephthalate (PET), polyether sulfone (PES) or polyimide film (Kapton, Upilex) Can be selected. Further, a photoresist for thick film photoresist or film may be used.

The thickness of the partition wall 14 is determined in consideration of the required adhesive strength of the upper and lower plates, but the thickness of the partition wall is preferably about 10 to 500 μm in consideration of the opening ratio.

The particles 12 are for image representation, and enclose two kinds of particles having different colors and charging characteristics. Non-charged particles may also be injected.

The kind of particles is not particularly limited and any particles used for image expression in the art may be used. That is, not only solids, but also particles of electrolyte solutions, suspensions, sol, gels, capsules, twist balls, and the like may be included.

Preferably, dry particles which do not use a viscous liquid, suspension or the like are preferred. That is, after injecting uncharged particles, it is preferable to inject dry collision-charged particles in which charged particles are formed by applying a voltage to the upper and lower electrodes to collide with each other to form charges due to collision. In the case of black and white particles, it is preferable to use white titanium oxide (TiO ₂ ) and black carbon black.

The insulating film 15 insulates the third electrodes 16a and 16b from the data electrodes 11 or the scan electrodes 21. As the material of the insulating film, polycarbonate, polyethylene terephthalate, and polyether sulfone, which are substrate materials such as various ceramics and liquid polymers, can be used.

In addition, as the insulating material 15, silicon oxide, silicon nitride, silicon carbide, aluminum oxide, tantalum oxide (Ta 2 O 3), or the like may be selected.

5 shows an electronic paper display device according to another embodiment of the present invention. As shown in FIG. 5, the third electrode 16 may be formed by patterning the same shape as the scan electrode 21 and the data electrode 11. That is, the third electrode 16 may be formed on the vertical extension line of the pixel space 13 by patterning the same shape as the scan electrode 21 and the data electrode 11.

This configuration prevents unwanted image cross-talk between adjacent pixels which may occur when one pixel is displayed by scan and data voltage when forming an image. That is, since the third electrode 16 is formed in the form of a pattern, voltage can be applied separately, which is very effective in removing non-uniformity between adjacent pixels.

In addition, since the third electrode 16 is formed only on the vertical extension line of the pixel space 13, the electrode material is saved, thereby reducing the unit cost. The pattern mask used when the scan electrode 21 and the data electrode 11 are formed By using it as it is, the manufacturing process can be simplified.

Hereinafter, a method of manufacturing the electronic paper display device of the present invention will be described with reference to FIGS. 4 to 5.

Since the method of forming the entire surface of the third electrode 15 on the substrates 10 and 20 is well known in the art, it may be selected from the conventional method. That is, the electrode is coated on the substrate by vapor deposition or spraying.

As a method of forming the third electrode 15 patterned as shown in FIG. 5, a photolithography method or the like may be used. In particular, if the resolution is not large, it can be formed by screen printing liquid ITO.

Next, an insulating film 15 is formed on the third electrode 16. As a method of coating, it is coated by vapor deposition or spray method. The deposition may be selected by sputtering, vacuum deposition, chemical vapor deposition, or the like, and may spray or spin coat an insulating material having a liquid form in addition to the vapor phase.

Next, the data electrode 11 and the scan electrode 21 are formed on the formed insulating film 15. The formation method of the data electrode 11 and the scan electrode 21 uses the same method. That is, the photolithography method etc. can be used as a formation method. In particular, since the patterned third electrode 16 has the same shape, the photomask used for forming the patterned third electrode may be used as it is.

Next, a plurality of partition walls 13 are formed on a region where the data electrode 11 is not positioned on the insulating layer 15 formed on the lower substrate 10. The partition wall can be formed by screen printing or photolithography, but the use of pixel-sized holes or bowl-shaped membranes can avoid the photolithography semiconductor process for the cost of the manufacturing process.

Alternatively, the partition wall 13 material film may be evenly applied, and then pressed into a mold having a shape of the pixel space 13. In this case, the partition wall is first formed, and then the data electrode 11 is formed using the above-described method. The compression molding method is preferable because it can mass-produce partition walls and reduce the manufacturing process.

Next, when the pixel space is formed by the inclined partition wall 14, particles 12 for image expression are injected and applied. That is, the particles may be injected and applied by spraying, screen printing, roll coating or spin coating, but are not limited thereto. Any method may be used as long as the particles can be injected into the pixel space.

Next, when all of the particles 12 are injected, the UV curable adhesive is coated on the partition wall 14, the upper substrate 20 having the third electrode formed thereon is laminated, and the upper substrate 20 is bonded by irradiating ultraviolet rays. . Thus, the charged particles 12 are enclosed in the pixel, thereby completing the electronic paper display device of the present invention.

In the case where the injected particles are collision-charged particles, they are generally injected into the pixel space without being charged. Therefore, after bonding of the upper substrate, a voltage is applied to the scan electrode 21 and the data electrode 11 so that the particles collide with each other. As a result, the charged particles are formed due to the collision to form charged particles.

The voltage applied to the third electrode 16 of the electronic paper display device manufactured as described above applies a voltage lower than the voltage applied to the scan electrode 21 and the data electrode 11. It may be applied at about half of the driving voltage. The magnitude of the voltage applied should also be within the limits allowed by the breakdown voltage characteristics of the insulating layer.

In the electronic paper display device manufactured as described above, since the third electrode 16 is disposed on a different layer from the other electrodes 11 and 21, the pixel size is reduced compared to the conventional structure in which the third electrode is arranged in parallel in one pixel. Can be expressed.

FIG. 6 is a diagram illustrating an electric field analysis of one pixel of a conventional structure, and FIG. 7 is a diagram illustrating an electric field analysis of one pixel of the present invention.

The effect of the tripolar structure of the present invention is shown by electric field simulation. Comparing the electric field analysis results of the conventional two-pole structure shown in FIG. 6 with the electric field analysis results of the three-pole structure shown in FIG. 7, it can be seen that the electric field strength of the three-pole structure of the present invention is large.

That is, in the tripolar structure of the present invention, the intensity of both edges of the data electrode of the lower substrate is higher than the edge of the electrode shown in Fig. 6 and the interval of the contour is narrow. In addition, it can be seen that the magnitude of the electric field strength on the data electrode is directed toward the lower side of the electrode than the conventional one.

Therefore, if the voltage applied between the scan electrode and the data electrode is the same, the structure of the present invention exhibits the effect of taking a larger electric field than the conventional structure, which means that it is driven by a low driving voltage, and thus a high contrast ratio can be realized even when a low voltage is applied. Can be.

As described above, the electronic paper display device having a three-pole structure of the present invention includes a third electrode formed on a different layer from the data electrode, the scan electrode, and solves the problem of applying the high resolution of the conventional three-pole structure and lowering the voltage. In addition, it is possible to implement an image so that a high contrast ratio can be obtained with low power consumption, and the effect of removing cross-talk between pixels is eliminated.

Claims (12)

A lower substrate and an upper substrate disposed to face each other at a predetermined interval; Third electrodes inscribed in the lower and upper substrates, respectively; An insulating film in contact with and insulated from each of the third electrodes; A scan electrode and a data electrode in contact with each of the insulating layers and formed at upper and lower portions of the pixel space, respectively; A plurality of partition walls contacting a predetermined region of each of the insulating films and dividing the pixels to form a pixel space; and An electronic paper display device having a three-pole structure comprising a plurality of charged particles enclosed in the pixel space. The electronic paper display device of claim 1, wherein the third electrode is disposed on an entire surface of the upper substrate and the lower substrate. The electronic paper display device of claim 1, wherein the third electrode is patterned in the same shape as the scan electrode and the data electrode and positioned on a vertical extension line of the pixel space. The electronic paper display device according to any one of claims 1 to 3, wherein the charged particles are dry type charged particles. The electronic paper display device according to claim 4, wherein the charged particles are carbon black and titanium oxide. The method of claim 1, wherein the third electrode, the data electrode, and the scan electrode have a thickness of 50 nm to 1000 nm, and the insulating layer has a thickness of 100 nm to 10000 nm. Electronic paper display element. The electronic paper display device according to any one of claims 1 to 3, wherein a voltage smaller than a voltage applied to the scan electrode and the data electrode is applied to the third electrode. The electronic paper display device according to any one of claims 1 to 3, wherein a voltage smaller than the breakdown voltage of the insulating layer is applied to the third electrode. The charged particle according to any one of claims 1 to 3, wherein the charged particles are charged in a charged state or charged particles enclosed in the pixel space and charged by mutual collisions after being charged in the pixel space. An electronic paper display device having a three-pole structure. Forming third electrodes on one surface of the upper and lower substrates, respectively; Forming an insulating film in contact with the third electrode; Forming a data electrode and a scan electrode in contact with the insulating film; Forming a plurality of partition walls on the insulating layer inscribed to the lower third electrode to divide the pixels and to provide a plurality of pixel spaces; Injecting one or more particles of charged and non-charged particles for image representation into the pixel space; And stacking an upper substrate on which the third electrode, the insulating film, and the scan electrode are formed, and bonding the upper substrate on the partition wall. 11. The method of claim 10, wherein when the non-charged particles are injected into the pixel space, the electronic paper having a three-pole structure further comprises the step of charging the non-charged particles by mutual collision by forming an electric field in the pixel space after the bonding step. Manufacturing method of display element. The tripolar structure of claim 10, wherein the third electrode is formed to be positioned in a specific region on a vertical extension line of the pixel space using a photomask patterned in the same manner as the data electrode and the scan electrode. Method of manufacturing an electronic paper display element.

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