KR101364632B1 - Electrophoretic display deivce and method of fabrication thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing an electrophoretic display device having a reduced manufacturing cost and a simplified manufacturing process, comprising: providing a first substrate and a second substrate including an image display unit and a non-image display unit including a plurality of pixels; Forming a thin film transistor on the first substrate, forming a protective layer on the first substrate on which the thin film transistor is formed, and forming a first pixel electrode in an image display area on the protective layer; And forming a partition wall defining a plurality of pixels in an image non-display area above the passivation layer, forming a second pixel electrode on the first pixel electrode and on sidewalls of the partition wall; The method includes filling an electrophoretic material in a unit pixel in a partition wall of the barrier rib, forming a common electrode on the second substrate, and bonding the first substrate and the second substrate to each other.

Description

Electrophoretic display device and its manufacturing method {ELECTROPHORETIC DISPLAY DEIVCE AND METHOD OF FABRICATION THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device and a method of manufacturing the same, and more particularly, to an electrophoretic display device and a method of manufacturing the same, which directly reduce an electrophoretic material on a substrate on which a thin film transistor is formed, thereby reducing manufacturing cost. It is about.

In general, an electrophoretic display device is an image display device using a phenomenon in which a pair of electrodes to which a voltage is applied is immersed in a colloid solution to move the colloid particles to either one of polarities. The electrophoretic display device has a wide viewing angle, a high reflectance, Power and the like, all kinds of electronic devices are attracting attention as electronic devices such as electric paper.

The electrophoretic display device has a structure in which an electrophoretic layer is interposed between two substrates, one of the two substrates is made of a transparent substrate and the other is made up of an array substrate on which a driving device is formed, An image can be displayed in the reflective mode.

1 is a view showing a structure of a conventional electrophoretic display element 1. Fig. 1, the electrophoretic display element 1 includes a first substrate 20 and a second substrate 40, a thin film transistor and a pixel electrode 18 formed on the first substrate 20, A common electrode 42 formed on the second substrate 40 and an electrophoretic layer 60 formed between the first substrate 20 and the second substrate 40. The electrophoretic layer 60 and the pixel And an adhesive layer (56) formed between the electrodes (18).

The thin film transistor includes a gate electrode 11 formed on the first substrate 2, a gate insulating layer 22 formed on the entire first substrate 20 on which the gate electrode 11 is formed, And a source electrode 15 and a drain electrode 16 formed on the semiconductor layer 13. The source electrode 15 and the drain electrode 16 are formed on the semiconductor layer 13, A protective layer 24 is formed on the source electrode 15 and the drain electrode 16 of the thin film transistor.

On the protective layer 24, a pixel electrode 18 for applying a signal to the electrophoretic layer 60 is formed. A contact hole 28 is formed in the passivation layer 24 so that the pixel electrode 18 on the passivation layer 24 is connected to the drain electrode 16 of the thin film transistor through the contact hole.

A common electrode 42 is formed on the second substrate 40 and an electrophoretic layer 60 is formed on the common electrode 42. At this time, an adhesive layer 56 is formed on the electrophoretic layer 60 to bond the second substrate 40 including the electrophoretic layer 60 to the first substrate 20. The electrophoretic layer 60 includes a capsule 70 filled with white particles 74 and black particles 76 having electrophoretic characteristics therein. When a signal is applied to the pixel electrode 18, an electric field is generated between the common electrode 42 and the pixel electrode 18, and white particles 74 and black particles 76 are moved to implement an image.

For example, when a negative (-) voltage is applied to the pixel electrode 18, the common electrode 42 of the second substrate 40 has a relatively positive potential, and white particles (+ 74 move toward the first substrate 20 and the black particles 76 having a negative charge move toward the second substrate 40. In this state, when light is input from the outside, that is, from the upper portion of the second substrate 40, since the input light is reflected by the black particles 76, black is realized in the electrophoretic display element.

On the other hand, when a positive voltage is applied to the pixel electrode 18, the common electrode 42 of the second substrate 40 has a negative potential, and white particles 74 having a positive charge The black particles 76 moving to the second substrate 40 and having a negative charge move to the first substrate 20. In this state, when light is input from the outside, that is, from the upper portion of the second substrate 40, since the input light is reflected by the white particles 74, white is realized in the electrophoretic display element.

However, in the conventional electrophoretic display element 1 having the above-described structure, the following problems arise.

In the conventional electrophoretic display device 1, the first substrate 20 and the second substrate 40 are separately manufactured, and then the first substrate 20 and the second substrate 40 are attached to each other by an adhesive layer 56 . That is, a thin film transistor for driving unit pixels on the first substrate 20 and a pixel electrode 18 for applying an electric field to the electrophoretic layer 60 are formed on the second substrate 40 in a separate process After the electrode 42, the electrophoretic layer 60 and the adhesive layer 56 are formed, the first substrate 20 and the second substrate 40 are bonded together.

However, since the unit pixel of the electrophoretic display element is formed to have a small size such as a width and a length of less than 150 micrometers, it becomes very difficult to align the electrophoresis layer exactly to this size. If the first substrate on which the electrophoretic layer and the thin film transistor are formed is not aligned correctly, the electric field can not be accurately transferred to the electrophoretic particles, which causes a driving error.

In addition, since the first substrate 20 and the second substrate 40 are manufactured in different processes, they must be transferred by the transfer means and adhered to each other in the adhesion process, so that the fabrication process can not be performed in-line.

On the other hand, the common electrode 42 is formed on the second substrate 40, and the electrophoretic layer 60 is coated and then the adhesive layer 56 is applied. In order to prevent the adhesive force of the adhesive layer 56 from being lowered or adhesion of foreign matter to the adhesive layer 56 in order to bond the first substrate 20 to the second substrate 40 by transferring the second substrate 40 to the adhesion process, 56) with a protective film attached thereto. In order to attach the transferred second substrate 40 to the first substrate 20, the protective film must be peeled from the second substrate 40. In the peeling process of the protective film, static electricity is generated, Which causes misalignment in the initial arrangement of the electrophoretic particles, which causes a comb-like moire in the operation of the electrophoretic display device.

As described above, in the conventional electrophoretic display device, since the first substrate 20 and the second substrate 40 are manufactured by different processes, the first substrate 20 and the second substrate 40 ) Or the process becomes complicated, static electricity is generated when the adhesive layer is peeled off, and the image quality is poor.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide a method of manufacturing a thin film transistor, in which an electrophoretic layer is formed directly on a substrate on which a thin film transistor is formed to prevent misalignment between the electrophoretic layer and the first substrate, And a method for producing the same.

Another object of the present invention is to form a first pixel electrode in an image display area of a pixel, and to form a second pixel electrode on a first pixel electrode and a partition wall, thereby degrading image quality due to electric field distortion in an area where a partition wall and a protective layer below the partition wall meet. It is to provide an electrophoretic display device and a method of manufacturing the same that can be prevented.

In order to achieve the above object, the electrophoretic display device manufacturing method according to the present invention comprises an image display region in which a plurality of pixels are arranged and a non-display region outside the image display region. Providing a first substrate comprising a second substrate corresponding to the first substrate; Forming a thin film transistor for each pixel on the first substrate; Forming a protective layer on the first substrate on which the thin film transistor is formed; Forming a first pixel electrode for each pixel on the passivation layer; Forming a partition wall derived from the protective layer between each pixel on the protective layer; Forming a second pixel electrode disposed on a sidewall of the partition wall protruding from the protective layer and connected to the first pixel electrode; Forming an electrophoretic layer by filling an electrophoretic material for each pixel defined by the barrier rib; Forming a common electrode on the second substrate; And bonding the first substrate and the second substrate together.

The electrophoretic material may include white particles and black particles having charge characteristics or color particles having charge characteristics.

The forming of the barrier layer may include forming an insulating layer on the protective layer on which the first pixel electrode is formed, and removing a part of the insulating layer by one of a photolithography process, a mold process, and an imprint process. . In addition, the step of forming the electrophoretic layer is a step of filling the electrophoretic material in the partition wall using one of the dropping method, squeeze method, casting printing method, bar coating printing method, screen printing method, mold printing method It includes.

The electrophoretic display device according to the present invention includes a first substrate and a second substrate including an image display area and a non-image display area including a plurality of pixels; A thin film transistor formed on the first substrate; A protective layer on the first substrate on which the thin film transistor is formed; Barrier ribs formed on the passivation layer to protrude above the passivation layer to define a unit pixel; A first pixel electrode formed on the image display portion on the protective layer; A second pixel electrode formed on a sidewall of the partition wall protruding from the protective layer and connected to the first pixel electrode; An electrophoretic material formed on the unit pixel between the barrier ribs and in contact with the first pixel electrode and the second pixel electrode; And a common electrode formed on the second substrate.

Since the electrophoretic layer is formed by directly applying the electrophoretic layer on the array substrate on which the thin film transistor is formed, the electrophoretic layer is formed on a separate substrate, The manufacturing cost can be reduced and the manufacturing process can be simplified because the electrophoresis layer can be formed in the in-line electrophoresis layer on the existing thin film transistor manufacturing line. In addition, since the electrophoretic layer is formed directly on the array substrate, an alignment process for accurately aligning the electrophoretic layer and the array substrate is not necessary, and thus the problem of misalignment between the first substrate and the electrophoretic layer can be fundamentally solved.

In addition, in the present invention, not only the first pixel electrode is formed in the protective layer, but also the second pixel electrode is formed on the protective layer and on the barrier rib to electrically connect the first pixel electrode and the second pixel electrode, The pixel electrode is also formed at the point where the protective layer meets to prevent the electric field of the region from being distorted when a voltage is applied, thereby preventing the image quality from being deteriorated.

1 is a view showing a conventional electrophoretic display device.
2A-2H illustrate a method of manufacturing an electrophoretic display device according to a first embodiment of the present invention.
3A and 3B illustrate a method of forming an electrophoretic layer of an electrophoretic display device according to the present invention, respectively.
4 is a diagram illustrating a structure of an electrophoretic display device according to a second exemplary embodiment of the present invention.

Hereinafter, an electrophoretic display device according to the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the electrophoretic layer is formed on the first substrate on which the thin film transistor is formed. That is, in the present invention, the electrophoretic layer is formed following the thin film transistor manufacturing process. Therefore, by forming the electrophoretic layer on the second substrate in another process and then bonding the second substrate to the first substrate, the manufacturing process can be greatly simplified compared to the conventional method of completing the electrophoretic display device.

In a conventional electrophoretic display device manufacturing process of forming an electrophoretic layer on a second substrate, the electrophoretic layer is supplied from another factory or even another part supplier and transferred to a manufacturing factory where the thin film transistor is formed, There is a problem that the manufacturing process is delayed and troublesome, and the second substrate is damaged in the process of transferring the second substrate by the transfer means such as a vehicle.

2A to 2G illustrate a method of manufacturing an electrophoretic display device according to a first exemplary embodiment of the present invention. Although the electrophoretic display device is substantially composed of a plurality of unit pixels, only one pixel is shown in the drawing for convenience of description.
Terms used in the present embodiment are defined. An area in which pixels are arranged on the first substrate is called an image display area, and an outer portion of the image display area, that is, an area where no pixel is formed, is called an image non-display area.

delete

First, as shown in FIG. 2A, a Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is formed on the first substrate 120 including an image display area and an image non-display area and made of a transparent material such as glass or plastic. After laminating a highly conductive opaque metal by a sputtering process, such as by etching by a photolithography process to form a gate electrode 111, the first gate electrode 111 is formed The gate insulating layer 122 is formed by stacking an inorganic insulating material such as SiO ₂ or SiNx by the CVD (Chemicla Vapor Deposition) method over the entire substrate 120.

Subsequently, as illustrated in FIG. 2B, a semiconductor material such as amorphous silicon (a-Si) is deposited on the entire first substrate 120 by CVD and then etched to form a semiconductor layer 113. Although not shown in the drawing, an amorphous silicon doped with impurities or doped with impurities is doped in a part of the semiconductor layer 113, and the ohmic contact (not shown) in which a source electrode and a drain electrode, which will be formed later, Thereby forming an ohmic contact layer.

Thereafter, as shown in FIG. 2C, an opaque metal having good conductivity such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is laminated on the first substrate 120 by sputtering and then etched to form a semiconductor. On the layer 113, strictly speaking, the source electrode 115 and the drain electrode 116 are formed on the ohmic contact layer, and then the entire first substrate 120 having the source electrode 115 and the drain electrode 116 formed thereon. A protective layer 124 is formed by stacking an organic insulating material such as BCB (Benzo Cyclo Butene) or photo acryl.

Also, although not shown in the figure, the protective layer 124 may be formed of a plurality of layers. For example, the protective layer 124 may be formed as a double layer of the inorganic insulating layer made of an inorganic insulating material such as a layer of organic insulation made of an organic insulating material such as BCB or the picture acrylic and SiO _2, or SiNx, inorganic An insulating layer, an organic insulating layer, and an inorganic insulating layer. As the organic insulating layer is formed, the surface of the protective layer 124 is formed flat and the interface characteristic with the protective layer 124 is improved by applying the inorganic insulating layer.

In addition, a contact hole 117 is formed in the protective layer 124 to expose the drain electrode 116 of the thin film transistor to the outside.

Subsequently, as illustrated in FIG. 2D, a first pixel electrode 118 is formed in each pixel of the image display area on the passivation layer 124. In this case, the first pixel electrode 118 is electrically connected to the drain electrode 116 of the thin film transistor through the contact hole 117.

The first pixel electrode 118 may be formed by stacking a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) or a metal such as Mo or AlNd, and then etching the same by a photolithography method. do. In addition, the first pixel electrode 118 may be formed of a plurality of metal layers. That is, it may be formed by successively stacking a plurality of metal layers, such as Cu and MoTi, and then etching by a photolithography method. The first pixel electrode 118 may be formed using carbon nanotubes or water-soluble conductive polymers.

Thereafter, as shown in FIG. 2E, the partition wall 180 is formed on the protective layer 124. The partition wall 180 is formed between the pixel and the pixel in the image display area, so that the pixel is substantially defined by the partition wall. The barrier ribs 180 are also formed on the first substrate 120 in the form of a matrix on the first substrate 120 so that the barrier ribs 180 are formed on the first substrate 120 along the boundary regions of the pixels arranged in a matrix, .

The barrier ribs 180 may be formed by laminating an insulating layer made of resin or the like and then etching them by a photolithography method using a photoresist. Alternatively, the barrier ribs 180 may be formed by laminating a photosensitive resin and etching them by a photolithography method. In addition, the partition wall 180 may be formed by printing the partition wall 180 patterned by a printing method such as a printing roll, and after manufacturing a mold having grooves corresponding to the partition wall, the insulating material of the mold is formed. It may be formed by transferring to the first substrate 120. The barrier ribs 180 may be formed in an imprint manner.

The formation of such a partition wall 180 is not limited by a specific method. The above description of specific methods is for convenience of explanation and is not intended to limit the present invention. The partition 180 may be formed by various known methods.

Thereafter, as illustrated in FIG. 2F, a second pixel electrode 118b is formed on the first pixel electrode 118a and on the sidewall of the barrier 180. In this case, since the first pixel electrode 118a and the second pixel electrode 118b are in direct contact with each other, the first pixel electrode 118a is electrically connected to each other. Thus, the second pixel electrode 118b is connected to the first pixel electrode 118a and the contact hole 117. It is electrically connected to the drain electrode 116 through the image signal is transmitted to the second pixel electrode 118b through the drain electrode 116.

Like the first pixel electrode 118a, the second pixel electrode 118b is formed by stacking a transparent conductive material such as ITO or IZO, a metal such as Mo and AlNd on the first pixel electrode 118a and the partition wall 180. After that, it can be formed by etching by a photolithography method, or can be formed by laminating carbon nanotubes or water-soluble conductive polymers. In addition, the second pixel electrode 118b may be formed as a double metal layer by sequentially stacking a plurality of metal layers such as Cu and MoTi and then etching.

The second pixel electrode 118b is formed not only on the first pixel electrode 118a formed in the unit pixel but also on the sidewall of the partition wall 180.

As described above, the second pixel electrode 118b is not formed only on the first pixel electrode 118a but extends to the sidewall of the partition wall 180 for the following reasons.

First, the image quality is improved by extending the second pixel electrode 118b to the sidewall of the partition wall 180. When only the first pixel electrode 118a is formed on the protective layer 124, the first pixel electrode 118a at the bottom of the partition wall 180, that is, in the corner regions of the partition 180 and the protection layer 124, is formed. When the first pixel electrode 118a is not normally formed and an electric field is applied, this area becomes a dead area where an electric field is abnormally applied. Such a warp region lowers the aperture ratio of the liquid crystal display element and causes many problems such as a decrease in contrast.

However, when the second pixel electrode 118b is formed on the sidewall of the partition wall 180 as in the present invention, since the second pixel electrode 118b is formed up to the corner region between the partition wall 180 and the protective layer 124. The dead zone does not occur, and as a result, the aperture ratio is improved, the contrast is improved, and the response speed is improved.

Second, as the second pixel electrode 118b is formed on the sidewall of the partition wall 180, the process is easy.

As will be mentioned later in the process, the electrophoretic material is filled in the upper region of the first substrate 120 defined by the partition wall 180 and the protective layer 124. When only the first pixel electrode 118a is formed on the passivation layer 124 and no other pixel electrode is formed on the sidewall of the partition wall 180, the first pixel electrode on the passivation layer 124 is filled when the electrophoretic material is filled. Since the surface characteristics of 118a and the barrier 180 are different from each other, the electrophoretic material is hardly applied to the surface of the barrier 180 when filling the electrophoretic material, so that the electrophoretic material is not easily injected. do. In order to prevent this, the surface of the barrier rib can be plasma-treated or chemically treated to improve the surface characteristics, but in this case, the process becomes complicated and the cost increases.

However, when the second pixel electrode 118b extends not only on the first pixel electrode 118a formed on the protective layer 124 but also to the sidewall of the partition wall 180 as in the present invention, the partition wall 180 does not need any surface treatment. Since the electrophoretic material is easily applied to the side surface of the sidewall, that is, the sidewall on which the second pixel electrode 118b is formed, the electrophoretic material can be smoothly filled into the partition 180.

Meanwhile, the second pixel electrode 118b is not formed on the partition wall 180. When the second pixel electrode 118b is formed on the partition 180, since the second pixel electrodes 118b formed in the pixels adjacent to each other are electrically connected to each other, they are electrically shorted between the adjacent pixels. When the second pixel electrode 118b is formed, the second pixel electrode 118b on the partition 180 may be removed.

In this regard, the second pixel electrode 118b may be formed to a part of the upper portion of the partition wall 180. That is, the second pixel electrode 118b is partitioned if the second pixel electrode 118b is removed from the upper portion of the partition 180 so that the second pixel electrode 118b of the adjacent pixel can be electrically separated. It may extend to the top of 180.

Thereafter, as shown in FIG. 2G, the electrophoretic material is filled in the pixels between the partition walls 180 to form the electrophoretic layer 160.

The electrophoretic material is composed of particles having positive and negative charge characteristics. The particles may be white particles 164 and black particles 165 or may be color particles such as cyan, magenta and yellow or red (R), green (G), and blue (Blue). ≪ / RTI >

In the case of white particles 164, particles having good reflectance such as TiO ₂ are used. In the case of black particles 165, particles having black characteristics such as carbon black are used. At this time, the white particles 164 may have a negative charge characteristic, the black particles 165 may have a positive charge characteristic, the white particles 164 may have a positive charge characteristic, and the black particles 165 may have positive and negative charge characteristics.

Also, in the case of color particles, coloring matter having charge characteristics, color particles may have a negative charge or a negative charge.

The electrophoretic material may include a dispersion medium such as a liquid polymer. This dispersion medium is a black particle, a white particle, or a colored particle, and may be a liquid such as a liquid polymer or air itself. As described above, when the dispersion medium is the air itself, it means that the particles move in the air as the voltage is applied without the dispersion medium.

When a liquid polymer is used as the dispersion medium, a black dispersion medium or a color dispersion medium may be used as the dispersion medium. In the case of using the black dispersion medium, since the light incident from the outside is absorbed, a clear black is displayed in the black implementation, and the contrast can be improved. In addition, the color dispersion medium is used when the electrophoretic material realizes color, and each color pixel includes a dispersion medium of a corresponding color, so that it becomes possible to express a clearer color in a color implementation.

In addition, the electrophoretic material may be a material in which capsules filled with a polymer binder are filled with an electronic ink. At this time, the electronic ink distributed in the capsule is composed of white particles (or white ink) and black particles (or black ink). At this time, the white particles and the black particles have positive and negative charge characteristics, respectively.

On the other hand, white particles, black particles, and color particles may not be used for only specific materials, but all known particles may be used.

The filling of the electrophoretic material into the barrier ribs 180 may be performed by various methods. A method of filling the electrophoretic material will be described below.

3A and 3B illustrate a method of forming an electrophoretic layer 160 by filling an electrophoretic material into the partition wall 180 formed on the first substrate 120.

The method illustrated in FIG. 3A relates to an inkjet method or a nozzle method. As shown in FIG. 3A, an electrophoretic material 160a is filled in a syringe (or nozzle) 185 and then the first substrate ( 120) The syringe 185 is positioned on the top. Thereafter, the partition wall 180 is moved by moving the syringe 185 on the first substrate 120 in a state where pressure is applied to the syringe 185 by an external air supply device (not shown). The electrophoretic material 160a is dropped on the pixels therebetween to form the electrophoretic layer 160 on the first substrate 120.

The method illustrated in FIG. 3B relates to a squeeze method, and as shown in FIG. 3B, after the electrophoretic material 160a is applied to an upper portion of the first substrate 120 on which the plurality of partition walls 180 are formed, a squeeze bar ( By moving on the first substrate 120 by 187, the electrophoretic material 160a is filled with pixels between the partition walls 180 in the unit pixel by the pressure of the squeeze bar 187 to form the electrophoretic layer 160. Will be.

Of course, the present invention is not limited to the above-described method. The above-described method shows an example of a process of forming the electrophoretic layer 160 that can be used in the present invention, and the present invention is not limited to this specific process. For example, various electrophoresis layer forming processes such as cast printing, bar coating printing, screen printing, and mold printing may be applied to the present invention.

Subsequently, as shown in FIG. 2H, a sealing material is coated on the electrophoretic layer 160 as described above to form a sealing layer 168 to seal the electrophoretic layer 160, and then the first substrate 120. Is bonded to the second substrate 140 to complete the electrophoretic display device. In this case, a color filter layer 169 may be formed on the sealing layer 168.

The sealing layer 168 is intended to prevent the electrophoretic layer 160 made of a dye having a low viscosity flows so that the dye overflows to an external or adjacent pixel. In addition, the sealing layer 168 prevents moisture from penetrating into the electrophoretic layer 160 and the electrophoretic layer 160 becomes defective.
The sealing layer 168 may be formed on both an upper surface of the electrophoretic layer 160 and an upper end of the sealing layer 168. However, in this case, some of the charged electrophoretic particles may be electrically attached to the silicide layer 168 to cause an error in the initial arrangement of the electrophoretic particles, so that the sealing layer 168 may be the electrophoretic layer 160. It may not be formed over the entire upper surface of the partition wall 160 may be formed only on the top.
On the other hand, in order to solve the problem that the electrophoretic particles are electrically stuck to the sealing layer 168, after the electrophoretic layer is filled in each subpixel, an interlayer is further formed on the electrophoretic layer to directly contact the electrophoretic particles with the silicide layer. Can be prevented. In this case, the electrophoretic particles do not stick to the silicide layer, thereby reducing the occurrence of defective pixels.
The interlayer may be a photosensitive organic material such as a partition wall, and in particular, Methyl Ethyl Ketone. The interlayer is formed by coating a nanometer thickness on top of the electrophoretic layer and the partition wall. The interlayer not only allows the formation of the silicide layer by temporarily sealing the electrophoretic layer temporarily, but also solves the problem of the electrophoretic particles sticking to the sealing layer.

delete

Although the first substrate 120 and the second substrate 140 are bonded together by the sealing layer 168 in order to improve the bonding strength between the first substrate 120 and the second substrate 140, May be formed. The adhesive layer may be formed only on the outer region of the electrophoretic display device, that is, on the sealing layer 168 above the barrier ribs 180, or on the entire sealing layer 168 above the electrophoretic layer 160.

The common electrode 142 is formed on the second substrate 140 made of a transparent material such as glass or plastic. The common electrode 142 is formed by stacking a transparent conductive material such as ITO or IZO.

Although not shown in the drawings, a color filter layer may be formed on the second substrate 140. This color filter layer is composed of R (Red), G (Green), B (Blue) color filter, and the color is realized when the electrophoretic material is composed of black particles and white particles.

The structure of the electrophoretic display device manufactured by the above method will be described in detail with reference to FIG. 2H.

As shown in FIG. 2H, in the electrophoretic display device according to the present invention, the barrier rib 180 is directly formed on the first substrate 120 and the electrophoretic layer 160 is also the barrier rib of the first substrate 120. Filled between 180, the electrophoretic layer 160 is directly formed on the pixel electrode 118 to directly contact the pixel electrode 118. Therefore, unlike the conventional electrophoretic display device, a separate adhesive layer for attaching the electrophoretic layer 160 between the electrophoretic layer 160, the pixel electrode 118, and the protective layer 124 is not required.

In the electrophoretic display device according to the present invention, the pixel electrode is formed of a double layer of the first pixel electrode 118a and the second pixel electrode 118b, and the first pixel electrode 118a is formed only in the unit pixel. The second pixel electrode 118b is also formed on the sidewalls of the unit pixel and the partition wall 180. Since the first pixel electrode 118a and the second pixel electrode 118b are electrically connected to each other in contact with each other on the passivation layer 124, the voltage applied to the first pixel electrode 118a through the thin film transistor is applied. Since it is also transmitted to the two pixel electrode 118b, a voltage is also applied to the second pixel electrode 118b between the partition wall 180 and the protective layer 124 so that the area becomes a dead area so that the image quality can be prevented from being degraded. do.

The driving of the electrophoretic display device having such a structure will be described below. When the electrophoretic material is composed of the white particles 164 and the black particles 165, since the white particles 164 have a positive charge or negative charge characteristics, a thin film transistor formed on the first substrate 120 by receiving a signal from the outside When a signal is applied to the pixel electrode 118 through the pixel electrode 118, the white particles 164 and the electrophoretic layer 160 are moved by an electric field generated between the pixel electrode 118 and the common electrode 142.

For example, when the white particles 164 have a positive charge, when a positive voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode of the second substrate 140 is applied. Since 142 has a relatively negative potential, the white particles 164 having a positive charge are moved toward the second substrate 140. Therefore, when light is input from the outside, that is, from the upper portion of the second substrate 140, the inputted light is mostly reflected by the white particles 164, so that white is realized in the electrophoretic display element.

At this time, according to the intensity of the voltage applied to the first pixel electrode 118a and the second pixel electrode 118b, the density of the white particles 164 moving toward the second substrate 140 or the second substrate 140 Since the interval is different, the intensity of the light input from the outside and reflected by the white particles 164 is also changed, it is possible to achieve the desired brightness.

On the contrary, when a negative voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode 142 of the second substrate 140 has a positive potential. The charged white particles 164 are moved to the first substrate 120 so that when the light is input from the outside, the input light is hardly reflected, thereby realizing black.

On the other hand, when the white particles 164 have a negative charge, when a positive voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode 142 of the second substrate 140 is applied. ) Has a relatively (-) potential, so that the white particles 164 having a (-) charge are moved toward the first substrate 120. Therefore, when light is input from the outside, that is, from the upper part of the second substrate 140, most of the input light is not reflected, so that black is implemented in the electrophoretic display device.

On the contrary, when a negative voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode 142 of the second substrate 140 has a positive potential. The charged white particles 164 are moved to the second substrate 140 so that when the light is input from the outside, the input light is reflected by the white particles 164, thereby implementing white.

When the electrophoretic material is formed of color particles, R, G, B color particles, cyan, magenta, magenta, yellow, etc., are applied to the first pixel electrode 118a and the second pixel electrode 118b. Color particles such as yellow may move the second substrate 140 to implement a color mixed with the corresponding color or other pixels.

When the electrophoretic material is composed of a polymer filled with white particles and a capsule filled with black particles, since the white particles and the black particles included in the electron ink distributed in the capsule have positive and negative charge characteristics, signals from outside When a signal is applied to the first pixel electrode 118a and the second pixel electrode 118b, an electric field generated between the first pixel electrode 118a and the second pixel electrode 118b and the common electrode 142 is input. White particles and black particles are separated by the capsule. For example, when a negative voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode 142 of the second substrate 140 has a relatively positive potential. The white particles with (+) charge move toward the first substrate 120, and the black particles with (−) charge move toward the second substrate 140. In this state, when light is input from the outside, that is, from the upper portion of the second substrate 140, since the inputted light is reflected by the black particles, black is realized in the electrophoretic display element.

On the contrary, when a positive voltage is applied to the first pixel electrode 118a and the second pixel electrode 118b, the common electrode 142 of the second substrate 140 has a negative potential, The charged white particles move to the second substrate 140, and the black particles carrying the negative charge move to the first substrate 140.

In this state, when light is input from the outside, that is, from the upper part of the second substrate 140, since the input light is reflected by the white particles, white is realized.

At this time, when the white particles and the black particles in the capsule have negative charge and positive charge characteristics, white and black can be realized by the opposite operation.

4 is a diagram illustrating a structure of an electrophoretic display device according to a second exemplary embodiment of the present invention. As shown in FIG. 4, the electrophoretic display device of this embodiment differs from the electrophoretic display device shown in FIG. 2H only in the shape of the pixel electrode, and the other structure is the same. Therefore, in the following description, different structures will mainly be described.

As shown in FIG. 4, the first pixel electrode 218a is formed on the passivation layer 224, and the second pixel electrode 218b is formed only on the sidewall of the partition wall 280. In the structure shown in FIG. 2H, the second pixel electrode is formed on the first pixel electrode and extends up to the sidewall of the partition wall. In this embodiment, the second pixel electrode 218b is not formed on the first pixel electrode 218a. It is formed only on the partition 280. However, even in this structure, the first pixel electrode 218a and the second pixel electrode 218b overlap each other at the lower portion of the partition wall 280 to be electrically connected to each other, thereby preventing the area from becoming a dead area.

The first pixel electrode 218a may be formed before or after the formation of the barrier rib 280. When the first pixel electrode 218a is formed before the partition wall 280 is formed, the transparent conductive layer or the metal layer is stacked and etched to form the first pixel electrode 218a, and then, in the image non-display area of the protective layer 224. The partition wall 280 is formed, and then the second pixel electrode 218b is formed on the sidewall of the partition wall 280 by laminating and etching the transparent conductive layer or the metal layer.

When the first pixel electrode 218a is formed after the formation of the barrier rib 280, the barrier rib 280 is formed in the image non-display area of the protective layer 224, and then the transparent conductive layer or the metal layer is laminated and etched to protect the protective layer. After forming the first pixel electrode 218a in the image display area on the upper side of the image display panel 224, the second pixel electrode 218b is formed on the sidewall of the partition wall 280 by laminating and etching the transparent conductive layer or the metal layer.

As described above, in the present invention, since the electrophoretic layer is directly formed on the first substrate, the electrophoretic layer is formed on the second substrate to protect the adhesive layer or the adhesive layer for attaching the electrophoretic layer to the second substrate. There is no need for a protective film. In addition, in the present invention, since the electrophoretic layer can be formed in a process line such as an existing thin film transistor forming process line, for example, an insulation layer, etc., a separate process line is not required, thereby further reducing manufacturing costs. do.

In addition, compared with the prior art in which an electrophoresis layer is manufactured by a separate factory or a manufacturer, and the electrophoresis layer is transported and attached to the second substrate and the second substrate is bonded to the first substrate again, It is possible to simplify the manufacturing process since the process such as adhesion of layers is not required.

In the above description, the structure of the electrophoretic display device is limited to a specific structure, but the electrophoretic display device of the present invention is not limited to the specific structure. In particular, various electrophoretic layers currently used as electrophoretic layers may be applied. That is, it may be applied to the electrophoretic layer of any structure that can be formed on the first substrate.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Therefore, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention.

120, 140: substrate 111: gate electrode
113: semiconductor layer 115: source electrode
116: drain electrode 118a, 118b: pixel electrode
124: protective layer 142: common electrode
160: electrophoresis layer 164: white particles
165 black particles 168 sealing layer

Claims (20)

A first substrate including a display region in which a plurality of pixels are arranged and a non display region outside the image display region, and a second substrate corresponding to the first substrate are provided. step;
Forming a thin film transistor for each pixel on the first substrate;
Forming a protective layer on the first substrate on which the thin film transistor is formed;
Forming a first pixel electrode for each pixel on the passivation layer;
Forming a partition wall derived from the protective layer between each pixel on the protective layer;
Forming a second pixel electrode disposed on a sidewall of the partition wall protruding from the protective layer and connected to the first pixel electrode;
Forming an electrophoretic layer by filling an electrophoretic material for each pixel defined by the barrier rib;
Forming a common electrode on the second substrate; And
And bonding the first substrate and the second substrate to each other. The method of claim 1, further comprising forming a sealing layer for sealing the electrophoretic layer. The method of claim 2, wherein the sealing layer is formed over the entire image display area. The method of claim 2, wherein the sealing layer is formed on the partition wall. The method of claim 1, wherein the bonding of the first substrate to the second substrate comprises forming an adhesive layer on at least one of the first substrate and the second substrate. The method of claim 1, wherein the electrophoretic material comprises charged white particles and black particles. The method of claim 1, wherein the electrophoretic material comprises charged color particles. The method of claim 6, wherein the electrophoretic material further comprises a dispersion medium. The method of claim 1, wherein the forming of the partition wall comprises:
Forming an insulating layer on the protective layer on which the first pixel electrode is formed; And
And removing a portion of the insulating layer by one of a photolithography process, a mold process, and an imprint process. The method of claim 1, wherein the forming of the electrophoretic layer is performed by using one of a dropping method, a squeeze method, a casting printing method, a bar coating printing method, a screen printing method, and a mold printing method. Electrophoretic display device manufacturing method comprising the step of filling the electrophoretic material. The method of claim 1, wherein the second pixel electrode extends over the first pixel electrode. The method of claim 1, wherein the forming of the thin film transistor comprises:
Forming a gate electrode on the first substrate;
Forming a semiconductor layer on the gate electrode;
Forming a source electrode and a drain electrode on the semiconductor layer. A first substrate and a second substrate including an image display area including a plurality of pixels and an image non-display area;
A thin film transistor formed on the first substrate;
A protective layer on the first substrate on which the thin film transistor is formed;
Barrier ribs formed on the passivation layer to protrude above the passivation layer to define a unit pixel;
A first pixel electrode formed on the image display portion on the protective layer;
A second pixel electrode formed on a sidewall of the partition wall protruding from the protective layer and connected to the first pixel electrode;
An electrophoretic material formed on the unit pixel between the barrier ribs and in contact with the first pixel electrode and the second pixel electrode; And
An electrophoretic display device comprising a common electrode formed on a second substrate. The method of claim 13, wherein the thin film transistor,
A gate electrode formed on the first substrate;
A semiconductor layer formed on the gate electrode; And
And a source electrode and a drain electrode formed on the semiconductor layer. The electrophoretic display device of claim 13, wherein the electrophoretic material comprises charged white particles and black particles. The electrophoretic display device of claim 13, wherein the electrophoretic material comprises charged color particles. 17. The electrophoretic display device of claim 15 or 16, wherein the electrophoretic material further comprises a dispersion medium. 18. The electrophoretic display device of claim 17, further comprising a sealing layer formed on the electrophoretic material to seal the electrophoretic material. The electrophoretic display device of claim 13, wherein the second pixel electrode extends over the first pixel electrode. The electrophoretic display device of claim 13, wherein the second pixel electrode extends to an upper portion of the partition wall.

Images