KR20120033681A - Electrophoretic display device and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An electrophoretic display device and a manufacturing method thereof are provided to include dispersing liquid and charging particles in a lower substrate, thereby omitting a separate bonding layer. CONSTITUTION: A lower substrate(200) includes a plurality of pixel electrodes. A partition wall(314) is formed on the lower substrate. The partition wall defines a plurality of sub pixels. A partition electrode(316) is formed in the partition wall. An electrophoretic dispersion solution(310) is included in each sub pixel. The electrophoretic dispersion solution has a color. Charged particles are filled with the electrophoretic dispersion solution. The charged particles have light reflecting features and are white.

Description

Electrophoretic display device and manufacturing method therefor {ELECTROPHORETIC DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to an electrophoretic display device, and more particularly, to an electrophoretic display device having an electrophoretic dispersion embedded in a lower substrate and a method of manufacturing the same.

The electrophoretic display device refers to a device for displaying an image by using an electrophoresis phenomenon in which colored charged particles move by an electric field applied from the outside. The electrophoretic phenomenon herein refers to a phenomenon in which charged particles move in a liquid by a Coulomb force when an electric field is applied to an electrophoretic dispersion liquid (electrophoretic ink) in which charged particles are dispersed in a liquid.

The electrophoretic display using the electrophoretic phenomenon has a feature of bistable, so that the original image can be displayed for a long time even if the applied voltage is removed. In other words, the electrophoretic display is a display device suitable for the field of e-books that does not require the rapid replacement of the screen because it can maintain a constant screen for a long time without applying a voltage continuously.

In addition, unlike a liquid crystal display, an electrophoretic display device has an advantage of not only having a dependency on a viewing angle, but also providing an image that is comfortable to the eye as much as paper, and thus demand is increasing.

1 is a view showing the structure of an electrophoretic display device according to the prior art.

As shown in FIG. 1, an electrophoretic display device according to the related art includes an electric substrate interposed between an oppositely bonded lower substrate 10 and an upper substrate 20 and between the lower substrate 10 and the upper substrate 20. It includes a electrophoretic film (30).

The electrophoretic film 30 may include the first and second adhesive layers 34 and 36 made of a transparent material, and the common electrode 38 made of a transparent conductive material positioned between the first and second adhesive layers 34 and 36. And a plurality of microcapsules 32 having an electrophoretic dispersion. Although not shown in FIG. 1, on the lower substrate 10, a plurality of pixel electrodes facing the common electrode 38 and a plurality of thin film transistors TFTs that apply voltages to the plurality of pixel electrodes are provided. Is formed.

Here, the electrophoretic dispersion (electrophoretic ink) includes positively charged particles and negatively charged particles, and the charged particles contained in the microcapsule 32 are moved by electrophoresis. By doing so, an image is realized.

The electrophoretic display device according to the related art manufactures the upper substrate, the lower substrate, and the lamination electrophoretic film 30, respectively, and then the electrophoretic film 30 is formed on the lower substrate 10 and the upper substrate 20. FIG. It is manufactured by interposing).

Therefore, since each of the upper substrate, the lower substrate, and the electrophoretic film to be produced separately, the manufacturing process is complicated and the manufacturing time takes a lot of disadvantages in efficiency decrease. In addition, there is a problem in that the manufacturing cost is increased by applying an electrophoretic film prepared separately.

In addition, the electrophoretic display device according to the related art has an adhesive layer for a special purpose in consideration of the contact between the lower substrate 10 and the microcapsule 32 in which the plurality of TFTs are formed. (34) needs to be formed, which causes a problem in that the process is complicated and expensive material costs are required.

In addition, the electrophoretic display device according to the related art needs to form a color filter on the upper substrate 20 for color display. In this case, a misalignment and a color filter between the lower substrate and the upper substrate are required. Due to the birefringence problem due to the thickness of the mixed color may occur, and thus, there is a problem that the color primary color is difficult to express.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an electrophoretic display device and a method of manufacturing the same, in which an electrophoretic dispersion having a color and charged particles are internalized on a lower substrate.

An electrophoretic display device according to the present invention for achieving the above technical problem, the upper substrate; A lower substrate including a plurality of pixel electrodes; Barrier ribs formed on the lower substrate to define a plurality of sub-pixels; Barrier rib electrodes formed on the barrier ribs; An electrophoretic dispersion inherent in each of the plurality of sub-pixels defined by the barrier rib and having a color; And charged particles filled in the electrophoretic dispersion, wherein the charged particles are white charged particles having a property of reflecting light.

Another electrophoretic display device according to the present invention for achieving the above technical problem, the upper substrate; A lower substrate including a plurality of pixel electrodes; Barrier ribs formed on the lower substrate to define a plurality of sub-pixels; Barrier rib electrodes formed on the barrier ribs; An electrophoretic dispersion inherent in each of the plurality of sub-pixels defined by the barrier rib and having a color; And charged particles charged with different polarities filled in the electrophoretic dispersion.

According to an aspect of the present invention, there is provided a method of manufacturing an electrophoretic display device, including: forming an upper substrate by forming a common electrode on a transparent upper base substrate; Forming a lower substrate by forming a thin film transistor and a pixel electrode on the lower base substrate; Forming a partition wall defining a sub pixel on the lower substrate; Forming a partition electrode on the partition wall; Filling the subpixels with an electrophoretic dispersion having a color and charged particles; And bonding the upper substrate and the lower substrate with the partition therebetween.

According to the above solution, the present invention provides the following effects.

First, the present invention does not require a separate adhesive layer by internalizing the electrophoretic dispersion and the charged particles having a color on the lower substrate, thus, the process can be simplified, and the manufacturing cost can be reduced.

Second, the present invention can improve productivity due to the simplification of the process.

Third, the present invention internalizes the electrophoretic dispersion having a color and the charged particles on the lower substrate, thereby preventing misalignment and mixed color defects that may occur when using the color filter.

1 is a view showing the structure of an electrophoretic display device according to the prior art.
2 is a schematic view of an electrophoretic display device according to a first embodiment of the present invention;
3 is an exemplary view showing various methods of forming a black layer applied to an electrophoretic display device according to a first embodiment of the present invention.
4 is an exemplary view for explaining a method of displaying various colors using the electrophoretic display device according to the first embodiment of the present invention.
5A to 5G illustrate a method of manufacturing an electrophoretic display device according to a first embodiment of the present invention.
6 is a schematic view of an electrophoretic display device according to a second embodiment of the present invention.
7 is an exemplary view for explaining a method of displaying various colors using an electrophoretic display device according to a second embodiment of the present invention.

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

FIG. 2 is a schematic view of an electrophoretic display device according to a first exemplary embodiment of the present invention, and shows sub pixels for displaying red, green, and blue colors.

As shown in FIG. 2, the electrophoretic display device according to the first embodiment of the present invention includes an upper substrate 100 including a common electrode 110 and a lower substrate 200 including a plurality of pixel electrodes 210. And a plurality of sub-pixels defined by partition walls 314 in which partition electrodes 316 are formed between the upper substrate 100 and the lower substrate 200, and defined by the partition walls 314. The electrophoretic layer 300 is filled with the electrophoretic dispersion 310 and the white charged particles 312 in the defined sub-pixel.

The upper substrate 100 may include an upper base substrate (film) 130 made of transparent glass or plastic, a common electrode 110 formed on the upper base substrate, and a top sealant formed on the common electrode 110. 120. Here, the upper base substrate 130 and the common electrode 110 of the upper substrate 100 should be transparent to display an image. Accordingly, the upper base substrate is formed of a flexible transparent material, and the common electrode 110 is a conductive transparent material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Is formed. The top sealant 120 is formed to planarize the upper substrate 100, to protect the common electrode 110, and to smoothly bond the electrophoretic layer 300 and the upper substrate 100. .

The lower substrate 200 includes a plurality of gate lines (not shown) and data lines (not shown) formed on the lower base substrate 230, and a plurality of sub pixels (color subs) defined by the partition wall 314. A thin film transistor (TFT) 220 formed at an intersection of the plurality of gate lines and the data lines so as to correspond to the pixels) and a pixel electrode 210 for applying a voltage to the plurality of sub pixels by switching the thin film transistors. It includes.

The lower base substrate 230 may be a glass substrate made of a transparent material, or a plastic substrate or a metal substrate may be used as the base substrate (film) in order to have flexibility. Here, the lower base substrate 230 is not necessarily transparent because it is located on the opposite side of the screen on which the image is displayed.

The gate line and the data line may be formed of a single layer made of silver (Ag), aluminum (Al), or an alloy thereof (Alloy) having a low resistivity, or in addition to such a single layer, chromium ( It may be formed as a multilayer film further comprising a film made of Cr), titanium (Ti), or tantalum (Ta).

A gate insulating layer formed of a nitride film (SiNx) may be positioned between the gate line and the data line, and a thin film transistor (TFT) 220 is formed at each intersection of the gate line and the data line. Here, the gate electrode of the thin film transistor TFT is connected to the gate line, the source electrode is connected to the data line, and the drain electrode is connected to the pixel electrode 210.

On the other hand, the electrophoretic display device according to the first embodiment of the present invention can implement a black (Black) by the black layer 240 that can absorb light, the black layer 240 is a lower substrate 200 ) May exist in various forms, and in FIG. 2, an example in which a protective layer for protecting the TFT 220 is used as the black layer 240 is illustrated. The black layer 240 will be described in detail with reference to FIG. 3.

The electrophoretic layer 300 includes electrophoresis embedded in each of a plurality of sub pixels defined by the partition wall 314 defining the plurality of sub pixels, the partition electrode 316 formed on the partition wall, and the partition wall 314. Dispersion 310 and white charged particles 312.

The partition wall 314 is formed on the upper substrate 100 or the lower substrate 200 to define a plurality of sub pixels. That is, the partition wall is formed on the lower substrate 200 to surround the pixel electrode 210 to define a plurality of sub pixels on which an image is displayed. An electrophoretic dispersion 310 including a plurality of white charged particles 312 charged with a positive (+) or negative (−) polarity is internalized in the sub-pixel defined by the partition 314.

Here, the electrophoretic dispersion 310 is a die coating method, casting method, bar coating method, slit coating method, dispensing method, squeezing (squeezing) ), A screen printing method, an inkjet printing method, a photo lithography method, and the like, may be internalized in the sub-pixel on the lower substrate 200.

On the other hand, the electrophoretic dispersion color liquid phase is embodied in red (R) electrophoretic dispersion 310a, green (G) electrophoretic dispersion 310b, blue (B) electrophoretic dispersion 310c, or yellow (yellow) ), Cyan, magenta electrophoretic dispersion, and the like. That is, the sub-pixels applied to the present invention may implement various colors according to the color of the electrophoretic dispersion 310 embedded therein.

The partition wall 314 is formed on the lower substrate 200. Specifically, the partition wall 314 is formed vertically on the lower substrate 200 in the direction of the upper substrate 100 so that the electrophoretic dispersion 310 may have the same physical properties. It may be formed of an organic material including an insulating polymer. The barrier rib 314 may be formed through a photo lithography or mold printing process, and formed to have a height of 1 μm to 100 μm.

The electrophoretic dispersion 310 includes a plurality of white charged particles 312 charged with positive (+) or negative (-) polarity.

On the other hand, the partition wall contacting the electrophoretic dispersion liquid is formed partition electrode 316 from the upper end to the lower end of the partition wall to form a transverse electric field in the electrophoretic dispersion.

The partition electrode 316 may be formed only on the partition surface in a flat plate shape as shown in FIG. 2A (hereinafter, such a partition electrode is simply referred to as a 'border wall electrode'), and FIG. As shown in FIG. 5, the lower electrode may be formed to be in contact with the lower substrate to be parallel to the pixel electrode (hereinafter, the barrier electrode is simply referred to as a 'bottom barrier electrode'), and the barrier electrode 316a and the barrier electrode below. It may be formed in a shape including all of the (316b). The partition electrode as described above may be equally applied to the electrophoretic display device according to the second exemplary embodiment of the present invention described below with reference to FIGS. 6 and 7.

The first embodiment of the present invention as described above is characterized in that the electrophoretic dispersion having a color directly formed on the lower substrate, comprising a charged particle 312 having one charge (Charge) characteristics Through the movement of charged particles in an electrophoretic dispersion composed of fluids of different colors, color, black, and white are realized. Particularly, color filters (C / F) Color can be implemented without).

In addition, in the first embodiment of the present invention, the partition wall may be formed on the upper plate, but it is advantageous in terms of alignment to be formed on the lower substrate rather than being formed on the upper plate.

In addition, the first embodiment of the present invention has the characteristic that white charged particles are used as the charged particles 312 having charging characteristics, and the white charged particles have a reflectivity as in TiO2. Good particles can be used.

On the other hand, the electrophoretic display device according to the first embodiment of the present invention configured as described above, the electrophoretic dispersion filled in the sub-pixels by the voltage applied to the partition electrode 316 or the pixel electrodes 210 ( As the white charged particles 312 in 310 are moved to the pixel electrode 210 or the partition electrode 316 in the electrophoretic dispersion, color, white, or black of the electrophoretic dispersion is realized. The implemented image is displayed through the upper substrate 100. This detailed operation method will be described in detail with reference to FIG. 4 below. First, with reference to FIG. 3, a method of forming a black layer required for implementing the black is described.

3 is an exemplary view illustrating various methods of forming a black layer applied to an electrophoretic display device according to a first embodiment of the present invention.

As described above, the electrophoretic display device according to the first embodiment of the present invention may be colored, white, or white depending on the position of the white charged particles due to the voltage applied to the partition electrode 316 or the plurality of pixel electrodes 210. Alternatively, black is implemented. Particularly, black is implemented in a form in which light incident through the upper substrate is absorbed by the lower substrate in a state in which charged particles are collected in the partition electrode 316. The black layer 240 capable of absorbing light should be formed.

That is, according to the first embodiment of the present invention, in order to realize black, a black layer is formed before or after the TFT process or a conventional passivation layer is used as the black layer. It may be formed.

Here, as a material for forming the black layer, a material containing black dye or pigment may be applied to an insulating organic material such as carbon black PR and photo acryl. That is, as the black layer, an insulating organic material having a black color may be used, and as such organic material, resin BM PR, Photo acryl material containing Black Dye / Pigment, or other Black organic insulating material may be applied.

On the other hand, the black layer may be formed by a method of coating on the entire surface of the lower substrate, the following three methods can be applied as a large forming method.

The first method is a method of forming a black layer before the process of forming a TFT. As shown in FIG. 3A, a black organic insulating material is coated on the entire lower base substrate 230 in an initial state. This is a method of forming a black layer 240a. This method has an advantage in that an inorganic film can be formed on a black organic film (black layer) formed for process stability and outgas prevention.

The second method is a method of forming a black layer during the process of forming a TFT. As shown in FIG. 3B, when the gate insulating layer or the passivation layer is formed, the black organic insulating material is completely coated. (Coating) to form the black layer 240b. In order to improve the black characteristic, it is preferable to form the protective layer as the black layer, as in the second method.

The third method is a method of forming a black layer after completion of the process of forming the TFT. As shown in FIG. 3C, the black layer 240c is coated on the entire surface of the pixel electrode 210 thinly. This is a method of preventing a voltage drop from occurring when an electric field is formed. At this time, the formation thickness of the black layer is preferably 30 μm or less, and the optimum thickness is preferably 5 μm or less.

On the other hand, of the three methods described above, the second method of forming the protective layer as the black layer during the process of forming the TFT is most preferred in terms of process simplification.

4 is an exemplary diagram for describing a method of displaying various colors using an electrophoretic display device according to a first embodiment of the present invention. Meanwhile, the white charged particles 312 included in the electrophoretic dispersion 310 applied to the electrophoretic display device according to the first embodiment of the present invention may be charged with positive (+) or negative (-) polarity. Hereinafter, for convenience of explanation, various color display methods of the first embodiment of the present invention will be described with an example in which the white charged particles 312 are charged with negative polarity.

First, when the electrophoretic display device according to the first embodiment of the present invention implements color, the pixel electrode 210 has a polarity opposite to that of the white charged particles 312 as shown in FIG. A positive polarity voltage is applied. At this time, the white charged particles 312 charged with the negative polarity move toward the pixel electrode and collect on the upper surface of the pixel electrode. Therefore, the light flowing into the sub pixel through the upper substrate is reflected back to the upper substrate by white charged particles collected on the upper surface of the pixel electrode, and the reflected light is red electrophoretic inside the sub pixel. Since the dispersion 310a penetrates and is released to the outside, a color (red) corresponding to the color liquid of the electrophoretic dispersion is realized.

Next, when the electrophoretic display device according to the first embodiment of the present invention implements white, the pixel electrode 210 has a negative polarity having the same polarity as that of the charged particles, as shown in FIG. -) Polarity is applied. At this time, the white charged particles charged with the negative polarity are moved in the opposite direction to the pixel electrode, that is, in the direction of the common electrode formed on the upper substrate, and collect on the surface of the upper substrate. Therefore, the light that is to be introduced into the sub pixel through the upper substrate is reflected back to the outside by the white charged particles 312 disposed at the boundary between the sub pixel and the upper substrate, thereby realizing white.

Finally, FIGS. 4C and 4D illustrate a method of implementing black using an electrophoretic display device according to a first embodiment of the present invention.

That is, when the electrophoretic display device according to the first embodiment of the present invention implements black, as a first method, as shown in FIG. 4C, the sidewall electrode is formed in a flat shape on the surface of the sidewall. A voltage of a positive polarity having a polarity opposite to that of the charged particles is applied to the (side wall electrode) 316a, or as shown in (d) of FIG. 4 as a second method, horizontal with the pixel at the lower end of the side wall. A voltage having a positive polarity having a polarity opposite to that of the charged particles may be applied to the sidewall electrode (side wall lower electrode) 316b, which is formed so as to be formed. At this time, the white charged particles charged with the negative polarity move toward the sidewall electrodes 316a or 316b formed on the left and right sides of the sub-pixels and collect on the sidewall electrodes. Therefore, the light introduced into the sub-pixel through the upper substrate may be introduced into the lower substrate without being disturbed by the white charged particles, and the light introduced into the lower substrate may be a black layer formed on the lower substrate. As it is absorbed by the 240, it implements black. On the other hand, in the second method using the sidewall lower electrode 316b, some of the light introduced into the sub-pixel are not absorbed by the black layer and are collected by the white charged particles 312 that are collected in the lower sidewall electrode. The black efficiency may be lowered because it may be reflected, but the sidewall bottom electrode needs to be considered when considering circuit implementation problems.

Hereinafter, a method of manufacturing an electrophoretic display device according to a first embodiment of the present invention will be described with reference to FIG. 5.

5A through 5G illustrate a method of manufacturing an electrophoretic display device according to a first exemplary embodiment of the present invention.

First, as shown in Figure 5a, such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the upper base substrate (film) 130 of transparent glass or flexible transparent plastic material The common electrode 110 is formed of a conductive transparent material.

Thereafter, as shown in FIG. 5B, the upper substrate is completed by forming the top sealant 120 on the common electrode 110 for bonding to the lower substrate or the electrophoretic layer. Here, the upper substrate 100 uses a glass or plastic substrate as the upper base substrate 130, and forms the common electrode 110 by depositing ITO. Meanwhile, when forming the common electrode, an alignment key for bonding in the final process and a scribing key for cutting later may be formed, or the top plate may be aligned using edge alignment without a separate alignment key.

Next, as shown in FIG. 5C, a material of copper, aluminum, and ITO is coated on the lower base substrate 230 on which the thin film transistor (TFT) 220 is formed so as to correspond to each of the sub-pixels. The pixel electrode 210 is formed to correspond to each of the sub-pixels by patterning through a graphing process. The pixel electrode 210 may be formed by further stacking nickel and / or gold on the above-described materials of copper, aluminum, and indium tin oxide (ITO). A gate line and a data line are formed on the lower base substrate, and the thin film transistor is formed in an area where the gate line and the data line cross each other. The data line is connected to the source electrode of the thin film transistor, the gate line is connected to the gate electrode of the thin film transistor, and the pixel electrode 210 is electrically connected to the drain electrode of the thin film transistor through a contact hole. On the other hand, since the electrophoretic dispersion should be directly coated on the lower substrate, the passivation layer 240 is preferably an organic film in terms of planarization. In addition, the passivation structure may be applied to a variety of structures, such as organic insulator single or inorganic / organic, inorganic / organic / inorganic. In addition, in the present invention, in order to implement a black (black), the black layer 240 must be formed on the lower substrate. In this case, the black layer may be formed in the three forms as described above, in particular, the conventional passivation It may be formed in the form of a protective layer as shown in Figure 5c using an organic insulator having a black color instead of a material. On the other hand, when the partition bottom electrode 316b formed to correspond to the pixel electrode among the partition electrodes, in particular, the partition bottom electrode may be formed together with the formation of the pixel electrode in FIG. 5C.

Next, as shown in FIG. 5D, the partition wall 314 is formed on the lower substrate on which the pixel electrode is formed. The barrier rib 314 may be formed through a photo lithography or mold printing process, and is formed to have a height of about 1 μm to about 100 μm to fill the electrophoretic dispersion 310 described below. Define the pixel. That is, the partition wall is formed to prevent color mixing of each color area of each sub-pixel, and various methods such as an imprinting method, a photolithography method, and a mold printing method may be applied as the partition wall forming method. The partition wall is formed to an appropriate thickness in accordance with the material properties. On the other hand, a method of forming a partition on the upper substrate is also possible, but it is advantageous in terms of alignment to form a partition on the lower substrate rather than forming on the upper substrate.

Next, as shown in FIG. 5E, the partition electrode 316 is formed on the inclined plane of the partition wall for driving the transverse electric field. Here, in FIG. 5E, only the partition surface electrode 316a is formed as the partition electrode 316, but as described above, the partition electrode may be formed only by the partition bottom electrode 316b described with reference to FIG. 2. In addition, the barrier rib electrode 316a and the barrier rib lower end electrode 316b may be formed in a form including both, and the barrier rib electrode may be formed through various processes according to its shape.

That is, the partition electrode 316 is to be formed together with the partition using a green sheet, as described, for example, in Publication No. 10-2001-0046458 (a plasma display element having the partition electrode and a method of manufacturing the same). Alternatively, the barrier rib may be formed directly on the barrier rib by a deposition process using a mask after the barrier rib is formed, and the barrier electrode material is filled in the sub-pixel space after the barrier rib is formed, and as shown in FIG. 5E by an etching process using a mask. It may be formed as. In this case, the line connected to each of the partition electrodes may be formed on the lower substrate together with the pixel electrode in the process of forming the pixel electrode in FIG. 5C, and then connected to the partition electrode through the process of FIG. 5E. In addition, each of the barrier electrodes may be configured to be switched by another thin film transistor (not shown) formed by the gate line and the data line. That is, the formation method and the driving method of the partition electrode may be configured in various ways.

Next, as illustrated in FIG. 5F, an electrophoretic dispersion 310 including a plurality of white charged particles 312 charged with positive (+) or negative (−) polarity is defined by the partition 314. The electrophoretic dispersion 310 is internalized in the lower substrate 200 by filling the sub pixel. Here, the electrophoretic dispersion 310 is a die coating method, casting method, bar coating method, slit coating method, dispensing method, squeezing (squeezing) ), A screen printing method, an inkjet printing method, a photo lithography method, and the like, may be internalized in a sub pixel on the lower substrate 200. A process of filling the subpixels with the electrophoretic dispersion 310 using the dispenser 400 is illustrated. On the other hand, the filling method of the electrophoretic dispersion may be applied to the various techniques disclosed as described above, but after the alignment using the TFT Align Key like the inkjet method, the electrophoretic dispersion can be dropped on each sub-pixel May also be applied. Meanwhile, white electrophoretic particles and electrophoretic dispersions having color may be separately injected, or white electrophoretic particles and electrophoretic dispersions having color may be injected in the form of a fluid. .

Lastly, as shown in FIG. 5G, the upper substrate 100 and the lower substrate 200 are bonded through the sealant with the electrophoretic layer 300 formed through the above-described process interposed therebetween. To this end, the present invention uses a method of coating and forming a top sealant 120 on the upper substrate, as mentioned in the description of Figure 5b. On the other hand, in the bonding of the upper substrate and the lower substrate, when the substrate is a plastic (Plastic), may be bonded in a laminating manner. Meanwhile, after the process as described above, a scribing process, a module process, and the like, which are not shown, may be performed. Accordingly, the electrophoretic display device is finally completed.

That is, in the electrophoretic display device according to the first exemplary embodiment of the present invention, the electrophoretic dispersion 310 filled in the sub-pixels through the processes described above is divided into the partition wall 314, the upper substrate 100, and the lower substrate ( The white charged particles contained in the electrophoretic dispersion are moved according to the driving voltage of the pixel electrode or the partition wall electrode, thereby realizing color, white, or black.

FIG. 6 is a diagram schematically illustrating an electrophoretic display device according to a second exemplary embodiment of the present invention, and shows sub-pixels for displaying red, green, and blue.

As shown in FIG. 6, the electrophoretic display device according to the second embodiment of the present invention includes an upper substrate 100 including a common electrode 110 and a lower substrate 200 including a plurality of pixel electrodes 210. And a plurality of sub-pixels defined by partition walls 314 in which partition electrodes 316 are formed between the upper substrate 100 and the lower substrate 200, and defined by the partition walls 314. The electrophoretic layer 300 is filled with the electrophoretic dispersion 310, the white charged particles 312, and the black charged particles 318 in the defined sub-pixel.

On the other hand, the electrophoretic display device according to the second embodiment of the present invention has a similar point in structure with the electrophoretic display device according to the first embodiment of the present invention shown in FIG. Therefore, the description of the same components as the structure and function of the electrophoretic display device according to the first embodiment of the present invention will be omitted, and hereinafter, among the configurations of the electrophoretic display device according to the second embodiment of the present invention Only components having structures and functions different from those of the electrophoretic display device according to the first embodiment will be described.

First, in the first embodiment of the present invention, only the white charged particles 312 charged with one and the same polarity are included in the electrophoretic dispersion 310 having color, but in the second embodiment of the present invention, the white charging In addition to the particles 312, black charged particles 318 having excellent light absorbing properties are further included, and the white charged particles and the black charged particles are charged with different polarities.

That is, if the white charged particles are charged with the negative (-) polarity, the black charged particles are charged with the positive (+) polarity. If the white charged particles are charged with the positive (+) polarity, the black charged particles are negative (-). It is charged with polarity.

Here, the white charged particles 312 may be a particle having excellent reflectivity, such as TiO 2 as described above, the black charged particles 318 are excellent in black properties that can absorb light, such as carbon black (Carbon Black) Particles can be used.

Second, although a black layer is required to implement black in the first embodiment of the present invention, since the black is implemented by using the black charged particles 318 in the second embodiment of the present invention, the first embodiment of the present invention. It is not necessary to be provided with the black layer as in the embodiment.

That is, the electrophoretic display according to the second exemplary embodiment of the present invention is the first exemplary embodiment of the present invention except that the electrophoretic display includes black charged particles in addition to the white charged particles and no black layer is provided. And structurally the same.

Therefore, the electrophoretic display device according to the second exemplary embodiment of the present invention does not require a drawing for explaining the black layer as shown in FIG. 3. In addition, the electrophoretic display device according to the second embodiment of the present invention may be manufactured through the same process as shown in FIG. 5, except that the forming of the black layer may be omitted and may be internalized on the lower substrate. The electrophoretic dispersion 310 to be added further includes black charged particles in addition to the white charged particles.

Meanwhile, since the electrophoretic display device according to the second embodiment of the present invention includes black charged particles in addition to the white charged particles, the electrophoretic display device according to the first embodiment of the present invention has a method of expressing color, white and black. There is a difference from the electrophoretic display device. Therefore, hereinafter, a method of expressing color, white, and black by the electrophoretic display according to the second exemplary embodiment of the present invention will be described in detail with reference to FIG. 7.

7 is an exemplary diagram for describing a method of displaying various colors using an electrophoretic display device according to a second exemplary embodiment of the present invention. In the following description, the white charged particles 312 are charged with negative polarity and the black charged particles 318 are charged with positive polarity for the convenience of description. An embodiment is described.

First, when the electrophoretic display device according to the second embodiment of the present invention implements black, the pixel electrode 210 has a positive polarity opposite to that of the black charged particles as shown in FIG. +) A polarity voltage is applied. At this time, the white charged particles 312 charged with the negative polarity move toward the pixel electrode and collect on the upper surface of the pixel electrode, and the black charged particles 318 charged with the positive polarity are upper part. It moves in the direction of the substrate and collects on the surface of the upper substrate. Therefore, the light that is to be introduced into the sub pixel through the upper substrate is absorbed by the black charged particles 318 disposed at the boundary between the sub pixel and the upper substrate, thereby implementing black.

Next, FIG. 7B illustrates a method of implementing white by using an electrophoretic display device according to a second embodiment of the present invention.

That is, when the electrophoretic display device according to the second embodiment of the present invention implements white, the pixel electrode 210 has a negative polarity having the same polarity as that of the white charged particles, as shown in FIG. -) A polarity voltage is applied. At this time, the white charged particles charged with negative polarity move in the opposite direction to the pixel electrode, that is, in the direction of the common electrode formed on the upper substrate, and collect on the surface of the upper substrate. The black charged particles charged with are collected on the surface of the pixel electrode. Therefore, the light that is to be introduced into the sub pixel through the upper substrate is reflected back to the outside by the white charged particles 312 disposed at the boundary between the sub pixel and the upper substrate, thereby realizing white.

Lastly, FIGS. 7C and 7D illustrate a method of implementing color using an electrophoretic display device according to a second exemplary embodiment of the present invention.

That is, when the electrophoretic display device according to the second embodiment of the present invention implements color, the sidewall electrode is formed in a flat plate shape on the surface of the sidewall, as shown in FIG. A negative (-) polarity having a polarity opposite to that of the black charged particles 318 is applied to the side wall electrode 316a, and a positive (+) polarity having a polarity opposite to the white charged particles 312 is applied to the pixel electrode. Alternatively, as a second method, as shown in FIG. 7D, a negative electrode having a polarity opposite to that of the black charged particles is formed on the sidewall electrode (lower sidewall electrode) 316b formed horizontally with the pixel at the lower end of the sidewall. Polarity may be applied and a positive polarity having a polarity opposite to that of the white charged particles may be applied to the pixel electrode. In this case, the white charged particles charged with the negative polarity are collected on the pixel electrode, and the black charged particles charged with the positive polarity are formed on the left and right sidewall electrodes 316a or 316b of the sub-pixel. It moves in the direction and collects on the sidewall electrode. Therefore, the light introduced into the sub-pixels through the upper substrate is reflected back to the upper substrate by the white charged particles on the upper surface of the pixel electrode formed on the bottom surface of the sub-pixel. Since the electrophoretic dispersion 310a inside the pixel is transmitted to the outside, the color corresponding to the color liquid (red) of the electrophoretic dispersion is realized. On the other hand, in the second method using the sidewall lower electrode 316b, some of the light flowing into the sub-pixels are not reflected by the white charged particles and are collected in the lower sidewall electrode. The color efficiency may be lowered because it can be absorbed by, but the sidewall bottom electrode needs to be considered in consideration of circuit implementation problems.

As described above, the electrophoretic display device according to the second embodiment of the present invention is different from the electrophoretic display device according to the first embodiment of the present invention, in particular, the method for implementing color, white and black. The electrophoretic display device according to the second embodiment of the present invention is characterized in that two power sources having two different polarities must be applied to the partition electrode and the pixel electrode, respectively, in order to express color. That is, as shown in FIG. 4, the electrophoretic display device according to the first embodiment of the present invention could express color, white, and black only by applying a power having one polarity. As can be seen from FIG. 7, the electrophoretic display device according to the second embodiment of the present invention has a feature that colors can be expressed only when two power sources having different polarities are applied.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

100: upper substrate 200: lower substrate
300: electrophoretic layer 310: electrophoretic dispersion
312: white charged particles 314: bulkhead
316: partition electrode 318: black charged particles

Claims (14)

Upper substrate;
A lower substrate including a plurality of pixel electrodes;
Barrier ribs formed on the lower substrate to define a plurality of sub-pixels;
Barrier rib electrodes formed on the barrier ribs;
An electrophoretic dispersion inherent in each of the plurality of sub-pixels defined by the barrier rib and having a color; And
It includes charged particles filled in the electrophoretic dispersion,
And the charged particles are white charged particles having a property of reflecting light. The method of claim 1,
The lower substrate,
And a black layer for absorbing light introduced through the sub-pixel through the upper substrate to realize black. The method of claim 1,
When a voltage having a polarity opposite to that of the charged particles is applied to the pixel electrode, the charged particles are disposed on the pixel electrode, and the light reflected by the charged particles reflects the color of the electrophoretic dispersion liquid in the sub-pixel. Electrophoretic display device, characterized in that implemented. The method of claim 1,
When a voltage having the same polarity as that of the charged particles is applied to the pixel electrode, the charged particles are disposed at a boundary between the sub pixel and the upper substrate, and light that is to flow into the sub pixel through the upper substrate is The electrophoretic display device, characterized in that the white reflected by the charged particles to implement the white. The method of claim 2,
When a voltage having a polarity opposite to that of the charged particles is applied to the partition electrode, the charged particles are disposed on the partition electrode, and the black layer absorbs light introduced through the sub pixel through the upper substrate. Electrophoretic display device, characterized in that the black. Upper substrate;
A lower substrate including a plurality of pixel electrodes;
Barrier ribs formed on the lower substrate to define a plurality of sub-pixels;
Barrier rib electrodes formed on the barrier ribs;
An electrophoretic dispersion inherent in each of the plurality of sub-pixels defined by the barrier rib and having a color; And
An electrophoretic display device comprising charged particles charged with different polarities filled in the electrophoretic dispersion. The method according to claim 6,
The charged particles,
Electrophoretic display device characterized in that the white charged particles having any one polarity, and the black charged particles having a polarity opposite to the polarity of the white charged particles. The method of claim 7, wherein
When a voltage having the same polarity as that of the black charged particles is applied to the pixel electrode, the black charged particles are disposed at a boundary between the sub pixel and the upper substrate, and are introduced into the sub pixel through the upper substrate. An electrophoretic display device, wherein light is absorbed by the black charged particles to implement black. The method of claim 7, wherein
When a voltage having the same polarity as that of the white charged particles is applied to the pixel electrode, the white charged particles are disposed at a boundary between the sub pixel and the upper substrate, and are introduced into the sub pixel through the upper substrate. Electrophoretic display device characterized in that the light is reflected by the white charged particles to the outside to implement white. The method of claim 7, wherein
When a voltage having a polarity opposite to that of the black charged particles is applied to the partition electrode and a polarity opposite to that of the white charged particles is applied to the pixel electrode, the white charged particles are disposed on the pixel electrode, and the white Electrophoretic display device characterized in that the light reflected by the charged particles implements the color of the electrophoretic dispersion in the sub-pixel. Forming an upper substrate by forming a common electrode on the transparent upper base substrate;
Forming a lower substrate by forming a thin film transistor and a pixel electrode on the lower base substrate;
Forming a partition wall defining a sub pixel on the lower substrate;
Forming a partition electrode on the partition wall;
Filling the subpixels with an electrophoretic dispersion having a color and charged particles; And
And bonding the upper substrate and the lower substrate with the partition therebetween. The method of claim 11,
The charged particles,
Electrophoresis comprising only white charged particles having one polarity, or white charged particles having one polarity and black charged particles having a polarity opposite to that of the white charged particles. Display device manufacturing method. The method of claim 11,
And forming a black layer capable of absorbing the light introduced through the upper substrate. The method of claim 13,
The black layer,
Or a protective layer for protecting the thin film transistor, or a front surface of the pixel electrode.

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